JP6061209B2 - Vehicle headlamp - Google Patents

Description

  The present invention relates to a vehicular headlamp, and more particularly to a vehicular headlamp capable of speeding up awareness in peripheral vision in a dark environment during night driving.

  Conventionally, in the field of vehicle headlamps, it has been required to improve the brightness so that it can be driven at night as well as in the daytime. To meet this demand, high luminous flux light sources such as halogen lamps and HID lamps are used. Various headlamps have been proposed to improve brightness (luminance, luminous flux, luminous efficiency, etc.) such as by improving the optical system (see, for example, Patent Document 1).

  In consideration of the characteristics of the human eye, which is more sensitive to blue light than red light in a dark environment during night driving, as shown in FIGS. 28 (a) and 28 (b), during night driving, From the viewpoint of improving visibility, the front area A1 is irradiated with light having a greater amount of blue component light than the red component light, and light having a greater amount of red component light is centered in the area A1 from the viewpoint of enhancing the color and shape recognition. A headlamp has also been proposed that irradiates a nearby area A2 (and an area A3 above a horizontal plane by a predetermined angle) (see, for example, Patent Document 2).

JP 2007-59162 A JP 2008-204727 A

  However, heretofore, it has not been known at all how blue light affects the perception of peripheral vision in a dark environment during night driving.

  29A is an explanatory diagram of the driver's central vision and peripheral vision, FIG. 29B is a diagram for explaining the relationship between the driver's central vision, peripheral vision, cones, rods, and the like, FIG. FIG. 6 is a flowchart for explaining a flow until the driver recognizes an object (such as a pedestrian or an obstacle) existing in the peripheral vision.

  A driver who is gazing at a distant place (see, for example, the three circles in FIG. 29A and the arrow in FIG. 29B) recognizes an object (such as a pedestrian or an obstacle) present in the peripheral vision. Considering in detail the flow up to, as shown in FIG. 30, the driver first notices the object in the peripheral vision (housing) (step S1: Yes), and then turns his eyes to that direction (step S2) After that, the object (color, shape, etc.) is recognized by the central view (cone) (step S3). When it is not noticed by peripheral vision (case) (step S1: No), it is overlooked (step S4). That is, in order to recognize an object existing in the peripheral visual field, it is important to notice first, and unless it is noticed, the target object existing in the peripheral visual field cannot be recognized.

  Especially in dark environments when driving at night, there are many situations that require awareness of peripheral vision (= body = dark vision sensitivity) (for example, turning left and right at an intersection, branching, changing lanes, lane keeping) It is important to speed up awareness in peripheral vision. For example, in front of the vehicle as viewed from the driver, the light from the vehicle headlamp is not sufficiently irradiated, so that the object present in the peripheral visual field is not noticeable. In addition, the wider the road width, the worse the awareness in front of the vehicle.

  Cones and rods are distributed on the retina of the human eye. FIG. 31 is a table summarizing the features of peripheral vision and central vision. As shown in FIG. 31, cones and rods are greatly different in location, number, function, role, and activity environment in which they are distributed. A rod cell is a cell for detecting an object such as a moving object to which a line of sight should be directed, and is distributed around the visual field (peripheral vision). Rod cells work in dark environments (dark vision). On the other hand, pyramidal cells are cells for judging detailed information and identifying and recognizing objects, and are distributed at the center of the visual field (central vision). Cone cells work in a bright environment (photopic vision). In other words, the human eye feels light from a bright place to a dark place as both photoreceptor cells (cones and rods) complement each other.

  The environment during night driving is not as bright as daytime (not photopic). In addition, the front lamp irradiates the front, so it is not dark (not a dark place). That is, the environment during night driving is a state of twilight vision between the photopic vision and the scotopic vision (a state where both the cone and the rod are activated). The adaptation illuminance is about 1 [lx].

  FIG. 32 shows the relative visual sensitivity V (λ) in photopic vision and the specific visual sensitivity V ′ (λ) in scotopic vision. The visual sensitivity changes from photopic vision to scotopic vision through dim vision. It represents that the peak of the curve shifts to the short wavelength side. This peak shift occurs due to the difference in spectral sensitivity between the cone and the rod.

  The inventors of the present application have conducted studies in consideration of the visual characteristics of the human eye, and as a result, if the energy component on the short wavelength side (blue light) is increased in a dark environment during night driving, We thought that somatic cells could be stimulated efficiently, and it would be possible to speed up awareness in peripheral vision.

  As a result of various experiments and repeated examinations, in the dark environment during night driving, as the short wavelength side energy component (blue light) increases, the perception in peripheral vision becomes faster (reaction) Based on this finding, the present invention has been completed.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a vehicular headlamp that can speed up awareness in peripheral vision in a dark environment during night driving.

  In order to solve the above-mentioned problem, the invention described in claim 1 is directed to a vehicle headlamp that forms a predetermined light distribution pattern on a virtual vertical screen facing the front surface of the vehicle. The first light source, the second light source, , A first optical system, a second optical system, a third light source, and a third optical system, and the predetermined light distribution pattern is an intersection of at least a horizontal line and a vertical line on the virtual vertical screen. A central region including: a peripheral region disposed on both sides of the central region on the virtual vertical screen; and a central region on the virtual vertical screen between the central region and the peripheral region. An intermediate region through which a sign moving to the center passes, and the first optical system is configured to irradiate the central region with light emitted from the first light source, and the second optical system. The system emits from the second light source Are configured to irradiate the peripheral region disposed on both sides of the central region, and the third optical system is configured to irradiate the intermediate region with light emitted from the third light source. The first light source is a light source having a lower S / P ratio than the second light source, the S / P ratio of the first light source is 1.5 or more, and the S / P of the second light source is The ratio is 2.0 or more, and the S / P ratio of the third light source is 1.8 or more.

  When the central region is irradiated with light emitted from a light source having the same S / P ratio as that of the second light source, a feeling of glare (glare) is given to the oncoming vehicle.

  According to the first aspect of the present invention, the central region is irradiated with light emitted from the first light source having a lower S / P ratio than that of the second light source. Compared with the case where the central region is irradiated with light emitted from the light source, it is possible to suppress the oncoming vehicle from being dazzled (glare).

  Further, according to the first aspect of the present invention, the light emitted from the second light source having a higher S / P ratio than that of the first light source is applied to the peripheral region, and thus the same S / P as that of the first light source. Compared to the case where the light emitted from the light source of the ratio is irradiated to the peripheral region, it is possible to speed up the awareness in the peripheral vision in the dark environment during night driving.

  As described above, according to the first aspect of the present invention, it is possible to suppress the oncoming vehicle from being dazzled (glare) and to be noticed in peripheral vision in a dark environment during night driving. Can be accelerated.

  According to the first aspect of the present invention, the peripheral area is irradiated with light emitted from the second light source having an S / P ratio of 2.0 or more in a dark environment during night driving. It becomes possible to speed up the notice in the.

  According to the first aspect of the present invention, the light is emitted from the first light source (S / P ratio of 1.5 or more) having a lower S / P ratio than the second light source (S / P ratio of 2.0 or more). Since it is the structure which irradiates light to a center area | region, compared with the case where the light radiated | emitted from the light source (S / P ratio 2.0 or more) of the same S / P ratio as a 2nd light source is irradiated to a center area | region It is possible to suppress the appearance of glare.

  According to the first aspect of the present invention, the intermediate region through which the relatively moving sign passes while traveling is irradiated with the third light source having a different S / P ratio from the first light source and the second light source. Is possible.

  According to the first aspect of the present invention, the light emitted from the third light source having an S / P ratio of 1.8 or more is irradiated to the intermediate region through which the relatively moving sign passes. This makes it possible to clearly show signs (particularly white, blue, and green) in a dark environment during night driving.

  According to a second aspect of the present invention, in the first aspect of the invention, the predetermined light distribution pattern further includes a front region disposed below a horizontal line on the virtual vertical screen, and the second optical system. Is configured to irradiate the peripheral region and the near region with light emitted from the second light source.

  According to the second aspect of the present invention, the light emitted from the second light source (for example, the second light source having an S / P ratio of 2.0 or more) is disposed before the horizontal line on the virtual vertical screen. By irradiating the area, it is possible to increase the brightness of the area in front of the vehicle without increasing the illuminance.

  As described above, according to the present invention, it is possible to provide a vehicular headlamp that can speed up awareness in peripheral vision in a dark environment during night driving.

It is a block diagram of the apparatus used for Experiment 1. FIG. 6 is a graph showing the S / P ratio of the light source used in Experiment 1. It is a spectral distribution of each light source used in Experiment 1. (A) Configuration example of light source having S / P ratio of 2.0 or more, (b) Configuration example (modification example) of light source having S / P ratio of 2.0 or more. It is a spectral distribution of LED5500K (new1) used for Experiment 1. FIG. It is a spectral distribution of LED5500K (new2) used for Experiment 1. FIG. It is an example of the spectral distribution of a light source with high awareness in peripheral vision predicted from the shape of visibility. It is the graph which plotted the measurement result (average value) of Experiment 2 on the coordinate system of S / P ratio on a horizontal axis and reaction time RT and an overlook rate on a vertical axis. The horizontal axis is an S / P ratio, and the vertical axis is a graph in which the measurement results of Experiment 2 (the average value of the reaction time RT and the average value of the miss rate) are drawn in the coordinate system of the reaction time RT and the miss rate. It is a figure for demonstrating the environment where the experiment 2 was performed. It is a figure for demonstrating the environment where the experiment 3 was performed. (A) The horizontal axis is the S / P ratio, the vertical axis is the coordinate system of the evaluation scale, and the evaluation value (average value) of Japanese in Experiment 3 is plotted. (B) The horizontal axis is the S / P ratio, the vertical axis. It is the graph which plotted the evaluation value (average value) of the American of Experiment 3 on the coordinate system whose axis is the evaluation scale. It is a block diagram of the apparatus used for Experiment 4. FIG. It is the graph which plotted the measurement result (average value) of Experiment 4 in the coordinate system of a horizontal axis on S / P ratio and a vertical axis | shaft on a feeling of brightness. It is the graph which plotted the measurement result (average value) of Experiment 5 in the coordinate system of the horizontal direction distance from the vehicle center in the left-right direction, and the vertical axis in the front distance from the vehicle front. It is the graph which plotted the measurement result (average value) of Experiment 5 in the coordinate system of the horizontal direction from the vehicle center in the left-right direction and the vertical axis in the illuminance. It is an example of a light distribution pattern (screen light distribution) that is noticed faster in peripheral vision. It is an example of a light distribution pattern (road surface light distribution) that is noticed faster in peripheral vision. It is an example of the light distribution pattern (driver | operator's viewpoint) which notices quickly by peripheral vision. It is the figure which measured the driver | operator's eyes | visual_axis position (eye point). It is a figure for demonstrating relationships, such as central vision, peripheral vision, a cone, and a rod. It is a figure for demonstrating that it becomes possible to accelerate | stimulate the recognition with respect to objects, such as a pedestrian who exists in a peripheral visual field, at the time of the right turn (or at the time of a left turn) in an intersection in the dark environment at the time of night driving. FIG. 20 is a front view of a vehicle V equipped with a vehicle headlamp 100 for forming a light distribution pattern that is quickly noticed in the peripheral view shown in FIGS. 17 to 19. (A) A cross-sectional view of the lamp unit 10 cut along a vertical plane including its optical axis, (b) a cross-sectional view of the lamp unit 20 cut along a vertical plane including its optical axis, (c) a lamp unit 30 It is sectional drawing cut | disconnected by the vertical surface containing the optical axis. (A) The front view of the shade 14 of the lamp unit 10, (b) The front view of the shade 24 of the lamp unit 20, (c) The front view of the shade 34 of the lamp unit 30. (A) It is sectional drawing of the reflector type lamp unit 40, (b) It is sectional drawing of a direct projection type lamp unit. This is an example of a light source 52 in which a plurality of white LEDs having different S / P ratios are arranged in a matrix. It is an example of the light distribution pattern (screen light distribution) of the conventional vehicle headlamp, (a) The light distribution pattern (road surface light distribution) of the conventional vehicle headlamp. (A) It is explanatory drawing of a driver | operator's central vision and peripheral vision, (b) It is a figure for demonstrating the relationship of a driver | operator's central vision, peripheral vision, a cone, a rod, etc. It is a flowchart for demonstrating the flow until a driver | operator recognizes the target object (pedestrian, obstacle, etc.) which exists in a peripheral visual field. It is the table | surface which summarized and contrasted the characteristics of peripheral vision and central vision. Specific luminous sensitivity V (λ) in photopic vision and specific luminous sensitivity V ′ (λ) in dark vision.

  Hereinafter, a vehicle headlamp according to an embodiment of the present invention will be described with reference to the drawings.

  The inventors of the present application have examined the visual characteristics of the human eye, and as a result, if the energy component on the short wavelength side (blue light) is increased in a dark environment during night driving, We thought that cells could be stimulated efficiently, and it would be possible to speed up awareness in peripheral vision.

  As a result of various experiments and repeated examinations, in the dark environment during night driving, as the short wavelength side energy component (blue light) increases, the perception in peripheral vision becomes faster (reaction) Based on this finding, the present invention has been completed.

  First, Experiments 1 to 5 performed by the inventors of the present application will be described.

  In the following experiment, the S / P ratio was used as an index representing the ratio of the energy component (blue color light) on the short wavelength side. The S / P ratio is expressed by the following equation. However, S (λ) is the spectrum of the light source, V (λ) is the specific luminous sensitivity in photopic vision, and V ′ (λ) is the specific luminous sensitivity in dark vision.

  The S / P ratio is obtained by measuring a spectrum of light emitted from a light source to be measured using a known measuring device (for example, a spectral radiance meter) and calculating using the above equation.

  Conventionally, in a vehicle headlamp, a light source having an S / P ratio of 2.0 or higher has not been used, and light from a light source having an S / P ratio of 2.0 or higher is detected in a dark environment during night driving. It has not been known at all how it affects the visual perception (= rod = scotopic sensitivity).

  Table 1 below shows the S / P ratio of a light source of a general vehicle headlamp measured by the inventors of the present application. A light source having a higher S / P ratio indicates that there are more energy components on the short wavelength side (light of blue color).

  Each light source in Table 1 is a light source used as a light source for a vehicle headlamp that is actually mounted on a commercially available vehicle. Referring to Table 1, it can be seen that the S / P ratio of the light source of a general vehicle headlamp is about 1.5 to 1.8.

  Halogen bulbs and HID bulbs are difficult to change the S / P ratio due to their structures, and the S / P ratios are approximately 1.46 and 1.75 shown in Table 1, respectively.

  Each LED in Table 1 is a white LED having a structure in which a blue LED element and a yellow phosphor such as YAG are combined. The white LED of this structure is adjusted in the concentration of the yellow phosphor so that the emission color meets the white range on the CIE chromaticity diagram specified by the law and looks natural to the driver's eyes. ing. In addition, the white range on the CIE chromaticity diagram specified by law is the coordinate value (0.31,0.28), (0.44, 0.38), (0.50, 0.38), (0.50, 0.44), (0.455, 0.44), ( It is the range surrounded by the straight line connecting 0.31,0.35).

  When the S / P ratio is less than 1.5, it is difficult for the white LED having the above structure to satisfy the white range on the CIE chromaticity diagram defined by law. Therefore, the lower limit of the S / P ratio is around 1.5. On the other hand, if the S / P ratio is up to about 2 (about 1.95), it is possible to satisfy the white range on the CIE chromaticity diagram specified by the law, but the S / P ratio is 1.8. If it approaches 2 and the yellow light is reduced, it becomes a bluish light and looks unnatural to the driver's eyes. Further, when the S / P ratio exceeds 1.8 and approaches 2, the efficiency decreases (the luminous flux decreases), and the brightness required for the light source of the vehicle headlamp cannot be secured. Therefore, the upper limit of the S / P ratio of the white LED having the above structure is about 1.8 from the viewpoint of constructing a highly efficient vehicle headlamp that looks natural to the driver's eyes.

  As described above, the S / P ratio of the light source of a general vehicle headlamp is conventionally about 1.5 to 1.8, and a light source having an S / P ratio of 2.0 or more is not used. Knowing how light from a light source with an S / P ratio of 2.0 or higher affects the awareness of peripheral vision (= enclosure = dark vision sensitivity) in a dark environment during night driving It was not done.

[Experiment 1]
The inventors of the present application have noticed that the S / P ratio (especially S / P ratio of 2.0 or more) is noticed in peripheral vision (= enclosure = dark vision sensitivity) in a dark environment during night driving. The following experiment was conducted in order to confirm the influence.

  FIG. 1 is a configuration diagram of the apparatus used in Experiment 1, and FIG. 2 is a graph showing the S / P ratio of the light source used in Experiment 1.

  In the experiment, an apparatus having the configuration shown in FIG. 1 was used, and a total of seven light sources having different correlated color temperatures and different S / P ratios as shown in Table 2 and FIG.

  FIG. 3 shows the spectral distribution of each light source used in Experiment 1. TH represents a halogen bulb, and HID represents a HID bulb. A number (for example, 4500K) attached to the side of the LED represents the correlated color temperature.

  LED4500K, LED5500K, and LED6500K are white LEDs with a combination of blue LED elements and yellow phosphors, and the correlated color temperature and S / P ratio are adjusted as shown in Table 2 by adjusting the concentration of yellow phosphors. did.

  FIG. 4A is a structural example of a light source (LED5500K (new1), LED5500K (new2)) having an S / P ratio of 2.0 or more.

  As shown in FIG. 4A, the LEDs 5500K (new1) and LED5500K (new2) are white LEDs having a structure in which a blue LED element B, a red LED element R, and a green phosphor G are combined. The S / P ratio was adjusted as shown in Table 2 by adjusting the green light to increase green light. The green phosphor G covers the blue LED element B and the red LED element R, and is excited by the blue light emitted from the blue LED element B to emit green light. When green light increases, the emission color becomes blue-green, which deviates from the white range on the CIE chromaticity diagram defined by law. Therefore, by adjusting the output by adding the red LED element R, the emission color was adjusted to be within the white range on the CIE chromaticity diagram defined by the law.

  The LED 5500K (new1) and the LED 5500K (new2) were adjusted so that the spectral distribution had a shape close to the spectral distribution of the light source that is predicted to be highly noticeable in peripheral vision.

  FIG. 5 shows the spectral distribution of the LED 5500K (new1), and FIG. 6 shows the spectral distribution of the LED 5500K (new2). FIG. 7 is an example of a spectral distribution of a light source with high awareness in peripheral vision predicted from the shape of visibility. According to the light source shown in FIG. 7, the green phosphor excited by blue light from the blue LED element (see numeral 1 in FIG. 7) and blue light from the blue LED element (see numeral 1 in FIG. 7). The white light is realized by the green light (see circle numeral 2 in FIG. 7) and the red light from the red LED element (see circle numeral 3 in FIG. 7). According to the spectral distribution shown in FIG. 7, the circle number 2 in FIG. 7 matches the visibility curve, so that it is possible to feel the brightness efficiently.

  5 and 6, the spectral distributions of the LEDs 5500K (new1) and the LED 5500K (new2) have a shape close to the spectral distribution of the light source predicted to be highly noticeable in the peripheral vision shown in FIG. I understand.

The experiment was performed according to the following procedure. First, as shown in FIG. 1, while the subject is gazing at the display (in which hiragana is displayed) installed at a position 2 m in front and reading the displayed characters, the left (or right) with respect to the front. Randomly presented gray color material irradiated by light source adjusted to constant brightness (1, 0.1, 0.01 [cd / m ² ]) at 30 °, 45 °, 60 ° and 75 ° positions did.

  The time from when the light source is turned on (after white light is presented) until the subject who notices the presentation light (the reflected light from the gray color material) presses the button at hand (reaction time RT) Was measured. The above was measured for each light source.

Note that the luminance setting values of the light source used in the experiment are 1, 0.1, and 0.01 [cd / m ² ], and the background luminance is 1 [cd / m ² ]. There are 4 subjects under 45 years old and 4 people over 45 years old.

  As a result of analyzing the measurement results, the inventors of the present application have found that the reaction rate decreases as the S / P ratio increases at the age of 45 years or older, and the miss rate decreases, that is, the S / P ratio at the age of 45 years or older. It has been found that as the P ratio increases, awareness in peripheral vision becomes faster.

  8 and 9 show the measurement results. FIG. 8 is a graph in which the measurement result (average value) is plotted in the coordinate system of the S / P ratio on the horizontal axis and the reaction time RT and the miss rate on the vertical axis. Note that the miss rate is the rate at which 2 seconds or more have passed since the subject noticed the presentation light after turning on the light source. The numbers in FIG. 8 are the coefficient of determination for each data group. FIG. 9 is a graph in which the measurement result (average value of reaction time RT, average value of miss rate) is drawn in the coordinate system of the S / P ratio on the horizontal axis and the reaction time RT and the miss rate on the vertical axis.

  Referring to FIG. 8, the reaction rate decreases as the S / P ratio increases to 2.0 or more at the age of 45 years or older, and the miss rate decreases, that is, the S / P ratio is 2 at the age of 45 years or older. It can be seen that the perception in peripheral vision becomes faster as the value increases to 0 or more.

  Based on this knowledge, light emitted from a light source having a S / P ratio of 2.0 or more is irradiated to the peripheral area in front of the vehicle, thereby speeding up awareness in peripheral vision in a dark environment during night driving. It becomes possible to configure a vehicular headlamp (the reaction speed RT is shortened and the miss rate is reduced). Under the age of 45 years, even when the S / P ratio increases, the reaction time and the miss rate are almost flat, and no correlation is seen between the two.

  Also, referring to FIG. 8, it can be seen from the correlation between the S / P ratio and the miss rate that the difference in awareness due to age is eliminated when the S / P ratio is 2.5 (or 2.5 or more).

  Based on this knowledge, light emitted from a light source with a S / P ratio of 2.5 (or more than 2.5) is irradiated on the surrounding area in front of the vehicle, so that it depends on age in a dark environment during night driving. It is possible to configure a vehicle headlamp that has no noticeable difference.

  In addition, comparing LED 5500K (new1) and LED5500K (new2) in FIG. 9 with other light sources, LED5500K (new1) and LED5500K (new2) have a reaction time RT under 45 years old and a reaction time RT over 45 years old. (And the difference between the missed rate under 45 years old and the missed rate above 45 years old) is small.

  In addition, comparing LED 5500K (new1) and LED5500K (new2) in FIG. 9 with other light sources, LED5500K (new1) and LED5500K (new2) have a short reaction time RT over 45 years old and a low oversight rate. I understand.

[Experiment 2]
The inventors of the present application have noticed that the S / P ratio (especially an S / P ratio of 2.0 or more) is noticed in peripheral vision (= enclosure = dark vision sensitivity) in a dark environment during actual night driving. The following experiment was conducted in order to confirm the influence.

  FIG. 10 is a diagram for explaining the environment in which Experiment 2 was performed.

  In the experiment, as shown in FIG. 10, assuming a vehicle turning right at the intersection, the vehicle V was stopped in the intersection. And the pedestrian M was located in front of the pedestrian crossing in the advancing direction of the vehicle V which turns right at the intersection (the blind spot position of the driver D). A total of three light sources having different S / P ratios (S / P ratios: 1.5, 2.0, and 2.5) were used as light sources for the vehicle headlamp.

  A light source having an S / P ratio of 1.5 and 2.0 is a white LED having a structure in which a blue LED element and a yellow phosphor are combined. By adjusting the concentration of the yellow phosphor, the S / P ratio is set to 1. Adjusted to 5, 2.0.

  The light source having an S / P ratio of 2.5 is a white LED having a structure in which a blue LED element, a red LED element, and a green phosphor are combined. By adjusting the concentration of the green phosphor, the S / P ratio is set to 2. Adjusted to 5.

  The experiment was performed according to the following procedure. The time until the driver D notices the pedestrian M after the pedestrian M starts walking from the front of the pedestrian crossing to the opposite side was measured. The above was measured for each light source. There are 4 subjects under 45 years old and 4 people over 45 years old.

  The measurement results are shown in Table 3 below.

  Referring to Table 3, it can be seen that the walking distance until the pedestrian is noticed becomes shorter as the S / P ratio increases, both under 45 and above 45.

  For example, when a light source with an S / P ratio of 1.5 and a light source with an S / P ratio of 2.5 are compared with a light source with an S / P ratio of 2.5, the light source with an S / P ratio of 2.5 may notice 26 cm faster. I understand. Assuming that the walking speed is 50 cm / second, a light source with an S / P ratio of 2.5 will be noticed 26/50 = 0.52 seconds faster. If the vehicle speed is assumed to be 1 m / s, the light source with an S / P ratio of 2.5 is stopped 52 cm before the pedestrian.

  Similarly, when comparing a light source with an S / P ratio of 1.5 and a light source with an S / P ratio of 2.0, the light source with an S / P ratio of 2.0 notices 13 cm faster for those under 45 years old. I understand. Assuming that the walking speed is 50 cm / second, a light source with an S / P ratio of 2.0 will be noticed 13/50 = 0.26 seconds faster. If the vehicle speed is assumed to be 1 m / s, the S / P ratio 2.0 light source will stop 26 cm before the pedestrian.

  On the other hand, when comparing a light source with an S / P ratio of 1.5 and a light source with an S / P ratio of 2.5, the light source with an S / P ratio of 2.5 notices 30 cm faster for those over 45 years old. I understand. Assuming that the walking speed is 50 cm / second, a light source with an S / P ratio of 2.5 will be noticed 30/50 = 0.6 seconds faster. If the vehicle speed is assumed to be 1 m / s, the light source with an S / P ratio of 2.5 is stopped 60 cm before the pedestrian.

  Similarly, when comparing a light source with an S / P ratio of 1.5 and a light source with an S / P ratio of 2.0 for a 45 year old or older, the light source with an S / P ratio of 2.0 notices 14 cm faster. I understand. Assuming that the walking speed is 50 cm / second, a light source with an S / P ratio of 2.0 will be noticed 14/50 = 0.28 seconds faster. Assuming that the vehicle speed is 1 m / s, the S / P ratio 2.0 light source is stopped 28 cm before the pedestrian.

  As described above, in the dark environment during actual night driving, the walking distance (until the pedestrian is noticed) as the S / P ratio increases, regardless of whether it is under 45 or older. It has been confirmed that the number of seconds) becomes shorter and the vehicle can stop before the pedestrian, that is, as the S / P ratio increases, the perception in the peripheral vision becomes faster.

  The following Table 4 is a table summarizing the reaction time RT and overlook rate of 45 years or older for halogen bulbs, HID bulbs, and white LEDs. The light source having an S / P ratio of 2.5 is a white LED having a structure in which a blue LED element, a red LED element, and a green phosphor are combined. By adjusting the concentration of the green phosphor, the S / P ratio is set to 2. Adjusted to 5. There are 4 subjects under 45 years old and 4 people over 45 years old.

  Comparing halogen light bulbs with S / P ratio 2.5 light sources, S / P ratio 2.5 light sources with a S / P ratio of 2.5 shorten reaction time RT by 0.12 seconds and overlook rate decreased by 8% I understand that Also, referring to Table 4, the reaction time RT of a light source having an S / P ratio of 2.5 is 0.79 seconds, which is a generally known reaction time during vehicle operation (determined as dangerous). It can be seen that the time from 0.7 to 0.9 seconds is sufficiently satisfied.

[Experiment 3]
Conventionally, it has not been known at all how the S / P ratio affects the appearance of the label color.

  The inventors of the present application conducted the following experiment in order to confirm how the S / P ratio affects the appearance of the marker color in a dark environment during night driving.

  FIG. 11 is a diagram for explaining an environment in which Experiment 3 was performed.

  In the experiment, as shown in FIG. 11, a five-color color chart S (a typical five-color chart used for signs, that is, a color chart including white, red, green, blue, and yellow) 50 m ahead of the stopped vehicle V. Arranged. A total of five light sources having different S / P ratios shown in Table 5 below were used as light sources for the vehicle headlamp.

  LED4500K, LED5500K, and LED6500K are white LEDs with a structure combining a blue LED element and a yellow phosphor, and the correlated color temperature and S / P ratio are adjusted as shown in Table 5 by adjusting the concentration of the yellow phosphor. did.

  The experiment was performed according to the following procedure. Irradiation with 5 color charts (white, red, green, blue, yellow) (illuminance: about 10 [lx]), subjective evaluation scale (3: how to see when illuminated with HID bulb, : Evaluate the appearance of the five-color color chart by using the following:: Visibility between 2: 1 and 3: 5: Clear clarity, 4: 3 and 5 did. The above was evaluated for each light source. The subjects were 16 Japanese and 43 Americans.

  As a result of analyzing the evaluation results, the inventors of the present application found that a light source with a high S / P ratio clearly appears regardless of race, and a light source with a high S / P ratio (especially the S / P ratio is 1.8 or more light sources) have found that white, blue and green are clear.

  FIG. 12A and FIG. 12B show the evaluation results. FIG. 12A is a graph in which the horizontal axis represents the S / P ratio, and the vertical axis represents the evaluation value (average value) of the Japanese in the coordinate system of the evaluation scale. FIG. The ratio and the vertical axis are graphs in which American evaluation values (average values) are plotted in the coordinate system of the evaluation scale.

  Referring to FIGS. 12 (a) and 12 (b), the evaluation value for the light source having a high S / P ratio is higher than the standard 3, and the light source having a high S / P ratio can be clearly seen regardless of race. It can also be seen that a light source having a high S / P ratio (particularly a light source having an S / P ratio of 1.8 or more) makes white, blue and green clear.

  Based on this knowledge, by irradiating the sign with light emitted from a light source with an S / P ratio of 1.8 or more, the sign can be clearly seen in a dark environment during night driving. An illumination lamp can be configured.

[Experiment 4]
Conventionally, it has not been known at all how the S / P ratio affects the feeling of brightness (luminance difference between the reference light source and the test light source).

  The inventors of the present application conducted the following experiment in order to confirm how the S / P ratio affects the feeling of brightness in a dark environment during night driving.

  FIG. 13 is a block diagram of the apparatus used in Experiment 4.

  In the experiment, an apparatus having the configuration shown in FIG. 13 was used, and a total of three white LEDs having different correlated color temperatures and S / P ratios shown in Table 6 below were used as test light sources.

  A total of two light sources having different S / P ratios shown in Table 7 below were used as reference light sources.

  LED3800K, LED5300K, and LED5800K are white LEDs with a combination of blue LED elements and yellow phosphors, and the correlated color temperature and S / P ratio are adjusted as shown in Table 6 by adjusting the concentration of yellow phosphors. did.

  The experiment was performed according to the following procedure. Look at the test light source with one eye and the reference light source with the other eye, and have the subject adjust the current value of the test light source so that the test light source has the same brightness as the reference light source. The spectral radiance of the light source was measured and the luminance difference between the reference light source and the test light source was calculated. The above was measured for each test light source and reference light source. There are 16 subjects.

  As a result of analyzing the measurement results, the inventors of the present application have found that the brightness of white LEDs increases as the S / P ratio increases.

  In FIG. 14, the horizontal axis represents the S / P ratio, and the vertical axis represents the brightness difference between the reference light source and the test light source as a measurement result in the coordinate system of the brightness difference when the brightness of the reference light source and the test light source are felt to be the same. It is the graph which plotted (average value).

  Referring to FIG. 14, the luminance difference is negative. This indicates that the test light source obtains the same brightness with a lower luminance value than the reference light source. Therefore, as shown in FIG. 14, the graph decreases to the right as the S / P ratio increases. As the S / P ratio of white LEDs increases, the feeling of brightness (brightness difference between the reference light source and the test light source) increases, and the white LEDs are about 13 to 26% for halogen bulbs and about 13% for HID bulbs. It can be seen that the brightness feeling of 3 to 17% (luminance difference between the reference light source and the test light source) increases.

[Experiment 5]
The inventors of the present application conducted the following experiment in order to confirm how the S / P ratio affects the feeling of brightness in a dark environment during actual night driving.

  In the experiment, a total of three light sources having different correlated color temperatures and different S / P ratios shown in Table 8 below were used as light sources for the vehicle headlamp.

  LED 4500K and LED 5500K are LEDs having a structure in which a blue LED element and a yellow phosphor are combined. By adjusting the concentration of the yellow phosphor, the correlated color temperature and the S / P ratio are adjusted as shown in Table 8. .

  The experiment was performed according to the following procedure. Irradiate the area in front of the vehicle (the area on the road surface in front of the vehicle in the own lane) with the same light distribution pattern, and report the area where the driver (subject) feels the brightest. It was measured. The above was measured for each light source. There are 5 subjects.

  As a result of analyzing the measurement results, the inventors of the present application do not widen the range in which the brightness is felt even if the illuminance increases, and the range in which the brightness is felt increases as the S / P ratio increases. It has been found that the brightness feeling of the area correlates with the S / P ratio, not the illuminance, and it is possible to increase the brightness feeling of the area in front of the vehicle by increasing the S / P ratio instead of the illuminance.

  15 and 16 show the measurement results. FIG. 15 is a graph in which measurement results (average values) are plotted in a coordinate system in which the horizontal axis is the distance in the left-right direction from the vehicle center and the vertical axis is the front distance from the front of the vehicle. FIG. 16 is a graph in which measurement results (average values) are plotted in a coordinate system in which the horizontal axis is the distance in the left-right direction from the vehicle center and the vertical axis is illuminance.

  Referring to FIGS. 15 and 16, the LED 5500K having a high S / P ratio has a wide range in which the LED 5500K feels brighter than other light sources, and the illuminance is equal or less than that. It can be seen that the range illuminated by the LED 5500K having a high P ratio is wider than the other light sources. That is, the feeling of brightness in the front area of the vehicle correlates with the S / P ratio, not the illuminance, and it becomes possible to increase the feeling of brightness in the front area of the vehicle by increasing the S / P ratio instead of the illuminance. I understand that.

  Based on this knowledge, the vehicle emits light emitted from a light source having an S / P ratio of 2.0 or more to the front front area of the vehicle without increasing the illuminance in a dark environment during night driving. It becomes possible to enhance the brightness of the front front area (area on the road surface in front of the vehicle in the own lane).

[Example of light distribution pattern that can be noticed faster in peripheral vision]
The inventors of the present application examined a light distribution pattern that is quickly noticed in peripheral vision based on the knowledge obtained from each of the experiments 1-5.

  Hereinafter, an example of a light distribution pattern that the inventors have noticed in peripheral vision will be described.

  FIG. 17 is an example of a light distribution pattern (screen light distribution) that is noticed quickly in peripheral vision, FIG. 18 is an example of a light distribution pattern (road surface light distribution) that is quickly noticed in peripheral vision, and FIG. It is an example of the light distribution pattern (driver | operator's viewpoint) which notices quickly.

  A light distribution pattern P shown in FIG. 17 is a light distribution pattern formed on a virtual vertical screen (disposed approximately 25 m ahead from the front of the vehicle) facing the front of the vehicle. The central region A1 and the peripheral region A2 , An intermediate area A3 and a front area A4. Each of the areas A1 to A4 is arranged at the position shown in FIG. 18 on the road surface, and is arranged at the position shown in FIG. 19 from the viewpoint of the driver.

  The center area A1 is an area corresponding to the central visual field (cone) of the driver who is gazing at a distant place (for example, the vanishing point).

  In this embodiment, as the center area A1, as shown in FIG. 17, a high light intensity area (referred to as a hot zone) including an intersection of a horizontal line and a vertical line on the virtual vertical screen, for example, on the virtual vertical screen Surrounded by a straight line connecting the left 5 ° up 2 ° position, the left 5 ° down 2 ° position, the right 5 ° down 2 ° position, the right 5 ° up 2 ° position, and the left 5 ° up 2 ° position. Selected areas.

  The reason why the central area A1 is set to 5 ° to the left and right is that the driver's line-of-sight position (eye point) is concentrated in a range of 5 ° to the left and right. FIG. 20 is a diagram in which the driver's line-of-sight position (eye point) is measured, and each black dot in FIG. 20 represents the line-of-sight position of the driver during driving. Referring to FIG. 20, it can be seen that the black spots are concentrated in the range of 5 ° to the left and the driver's line-of-sight position (eye point) is concentrated in the range of 5 ° to the left and right.

  The reason why the central area A1 is set to 2 ° in the vertical direction is to mainly satisfy the brightness required by the law and form a light distribution with high distant visibility.

  The center area A1 may be an area corresponding to the center visual field (cone) of the driver who is gazing at a distant place (for example, the vanishing point). It is not limited to the 2 ° region.

  The light source that irradiates the central region A1 is a light source having a lower S / P ratio than the light source that irradiates the peripheral region A2 (in this embodiment, a light source having an S / P ratio of 2.0 is exemplified) (in this embodiment). And a light source having an S / P ratio of 1.5). The reason is that if the central area A1 is irradiated with light emitted from a light source having the same S / P ratio as the light source that irradiates the peripheral area A2 (for example, a light source having an S / P ratio of 2.0), the oncoming vehicle is dazzled. This is to suppress a feeling of glare.

  The center area A1 is arranged on the road surface in an area 5 ° to the left and right with respect to the reference axis AX extending in the vehicle front-rear direction as shown in FIG. 18, and at the position shown in FIG. .

  As described above, the light source (in this embodiment, the S / P ratio is lower) than the light source that irradiates the peripheral area A2 (in this embodiment, a light source having an S / P ratio of 2.0 is exemplified). By irradiating the center area A1 in front of the vehicle with light emitted from a light source of 1.5), it is possible to suppress the oncoming vehicle from being dazzled (glare).

  The peripheral area A2 is an area corresponding to the peripheral visual field (housing) of the driver who is gazing at a distant place (for example, the vanishing point).

  In this embodiment, as the peripheral area A2, as shown in FIG. 17, both the left and right sides of the central area A1 on the virtual vertical screen, for example, a position 15 ° above 6 ° to the right and 6 ° above 80 ° to the right on the virtual vertical screen. Right region A2R surrounded by a straight line connecting a position of °, a position of 80 ° down to the right, 14 ° down to the right, 15 ° down to the right, 14 ° down to the right, and 15 ° up to the right. Select left region A2L surrounded by straight line connecting 6 ° position, left 80 ° up 6 ° position, left 80 ° down 14 ° position, left 15 ° down 14 °, left 15 ° up 6 ° position did.

  The reason why the right region A2R is set to the right 15 ° to the right 80 ° is that many rods are distributed in the range of 15 ° or more on the left and right, and this is stimulated. The reason why the left region A2L is set to 15 ° to 80 ° left is also the same. Referring to FIG. 21, it can be seen that the casings are widely distributed in a range of 15 ° or more on the left and right. FIG. 21 is a diagram for explaining the relationship between central vision, peripheral vision, cones, rods, and the like.

  The reason why the right region A2R is in the range of 6 ° to 14 ° is mainly to illuminate an object such as a pedestrian during a right turn at an intersection. The reason why the left region A2L is in the range of 6 ° to 14 ° is the same.

  The peripheral area A2 may be an area corresponding to the peripheral visual field (enclosure) of the driver who is gazing at a distant place (for example, the vanishing point). It is not limited to the region of 80 ° (left 15 ° to left 80 °), upper 6 ° to lower 14 °.

  The light source that irradiates the peripheral area A2 is a light source having an S / P ratio of 2.0 or more (in the present embodiment, a light source having an S / P ratio of 2.0 is exemplified). The reason why the light source has an S / P ratio of 2.0 or higher is that as the S / P ratio increases to 2.0 or higher, the perception in peripheral vision becomes faster (the reaction speed becomes shorter and the missed rate decreases). (See Experiment 1 and Experiment 2) to speed up awareness in peripheral vision in a dark environment during night driving (reduce the reaction rate and reduce the miss rate).

  The peripheral area A2 is arranged on the road surface in an area of 15 ° right to 80 ° and 15 ° left to 80 ° left with respect to the reference axis AX extending in the vehicle longitudinal direction as shown in FIG. From the point of view, they are arranged at the positions shown in FIG.

  As described above, the light emitted from the light source having an S / P ratio of 2.0 or more is irradiated on the peripheral area A2 (A2R, A2L) in front of the vehicle, for example, in a dark environment during night driving. As shown in FIG. 22, it becomes possible to speed up the awareness of an object such as a pedestrian M present in the peripheral visual field at the time of a right turn (or a left turn) at an intersection.

  The intermediate area A3 is an area that covers an area through which a sign that moves relatively during traveling passes.

  In the present embodiment, as shown in FIG. 17, as the intermediate area A3, between the central area A1 and the peripheral area A2, for example, a position of 5 ° above the right 5 ° on the virtual vertical screen, 5 ° below the right Right region A3R surrounded by a straight line connecting a position of 1 °, a position of 15 ° to the right and a position of 2 ° to the right, a position of 15 ° to the right and a position of 3 ° to the right, and a position of 5 ° to the right and 5 ° to the right. A straight line connecting the left 15 ° up 3 ° position, the left 15 ° down 2 ° position, the left 5 ° down 1 ° position, the left 5 ° up 0.5 ° position, and the left 15 ° up 3 ° position The left region A3L surrounded by is selected.

  The reason for arranging the two areas of the right area A3R and the left area A3L is to illuminate the signs installed on both sides of the road.

  The reason why the trapezoidal shape in which the vertical width of the right region A3R is increased from the center toward the outside (from the right 5 ° to the right 15 °) is that the apparent height changes from low to high during traveling. This is to illuminate only the sign. The reason for making the left region A3L trapezoidal shape whose vertical width increases as it goes outward from the center (from 5 ° to 15 ° to the left) is also the same.

  The intermediate area A3 is not limited to the trapezoidal shape as long as it covers an area through which a sign that moves relatively during traveling passes from the viewpoint of the driver. For example, the intermediate area A3 may have a rectangular shape including the trapezoidal shape.

  The light source that irradiates the intermediate area A3 is a light source having an S / P ratio of 1.8 or more (in this embodiment, a light source having an S / P ratio of 1.8 is exemplified). The reason why the light source having an S / P ratio of 1.8 or more is that a light source having a high S / P ratio (particularly a light source having an S / P ratio of 1.8 or more) clearly shows white, blue, and green. This is because signs (particularly white, blue, and green) can be clearly seen in a dark environment during night driving based on (Experiment 3).

  The intermediate area A3 is arranged on the road surface in areas of 5 ° to right 15 ° and 5 ° to left 15 ° with respect to the reference axis AX extending in the vehicle longitudinal direction as shown in FIG. From the point of view, they are arranged at the positions shown in FIG.

  As described above, by irradiating light emitted from a light source having an S / P ratio of 1.8 or more to the intermediate area A3 (A3R, A3L) in front of the vehicle, a sign ( In particular, white, blue and green) can be clearly seen.

  The front area A4 is an area that covers a front area in front of the vehicle (an area on the road surface in front of the vehicle in the own lane).

  In the present embodiment, as the front area A4, as shown in FIG. 17, it is below the horizontal line on the virtual vertical screen (in front of the driver's lane from the viewpoint of the driver), for example, 9.4 ° to the left on the virtual vertical screen A region surrounded by a straight line connecting a position of 3 °, a position of 17 ° to the left and 8 ° to the bottom, a position of 16.7 ° to the bottom and 8 ° to the right, and a position of 3 ° to the bottom of 8.3 ° to the right was selected.

  The reason why the front area A4 has a trapezoidal shape with its width expanding as it goes vertically downward on the virtual vertical screen (from 3 degrees below to 8 degrees below) is to illuminate only the area on the road surface in front of the vehicle in front (See FIG. 19).

  The foreground area A4 may be an area that covers an area in front of the vehicle (area on the road surface in front of the vehicle in the own lane), and is not limited to the trapezoidal shape. For example, the front area A4 may have a rectangular shape including the trapezoidal shape.

  The light source that irradiates the front area A4 is a light source having the same S / P ratio as 2.0 in the peripheral area A3 (in this embodiment, a light source having an S / P ratio of 2.0 is exemplified). The reason why the light source has an S / P ratio of 2.0 or more is that the brightness feeling in the front area of the vehicle correlates with the S / P ratio, not the illuminance, and the vehicle is increased by increasing the S / P ratio instead of the illuminance. Based on the knowledge that it is possible to increase the brightness of the front front area (see Experiments 4 and 5), the front front area of the vehicle is increased by increasing the S / P ratio instead of the illuminance in a dark environment during night driving. This is to increase the feeling of brightness.

  The front area A4 is arranged on the road surface in an area 5 to 15 m ahead of the vehicle and 3.5 m wide as shown in FIG. 18, and at the position shown in FIG. 19 from the viewpoint of the driver.

  As described above, by irradiating the front area A4 in front of the vehicle with light emitted from a light source having an S / P ratio of 2.0 or more, the vehicle does not increase in illuminance in a dark environment during night driving. It becomes possible to enhance the brightness of the front front area (area on the road surface in front of the vehicle in the own lane).

[Configuration example of vehicle headlamp]
Next, a configuration example of the vehicle headlamp for forming the light distribution pattern P that is quickly noticed in the peripheral view shown in FIGS. 17 to 19 will be described.

  FIG. 23 is a front view of a vehicle V equipped with a vehicle headlamp 100 for forming a light distribution pattern that is quickly noticed in the peripheral view shown in FIGS. 17 to 19, and FIGS. 24 (a) to 24. (C) is sectional drawing which cut | disconnected the lamp units 10-30 which comprise the vehicle headlamp 100 by the vertical surface containing the optical axis.

  As shown in FIG. 23, the vehicle headlamp 100 of the present embodiment is disposed on both the left and right sides of the front surface of a vehicle V such as an automobile, and includes three lamp units 10, 20, and 30 on one side. Each lamp unit 10-30 is connected to a known aiming mechanism (not shown) so that the optical axis can be adjusted.

[Lamp Unit 10]
The lamp unit 10 is a projector-type lamp unit that irradiates the central area A1, and as shown in FIG. 24A, the projection lens 11 and the projection lens 11 are arranged on an optical axis AX ₁₀ extending in the vehicle front-rear direction. rear focal point F ₁₁ rear side and the optical axis AX ₁₀ light source 12 arranged in the vicinity from the reflective surface 13 is disposed above the light source 12, so as to shield a part of light from the light source 12, a projection lens 11 and a shade 14 disposed between the light source 12 and the like.

The projection lens 11 is disposed on an optical axis AX ₁₀ that is held in a lens holder or the like (not shown) and extends in the vehicle front-rear direction. The projection lens 11 is, for example, a plano-convex aspherical projection lens having a convex front surface and a flat rear surface.

  The light source 12 is, for example, a white LED (for example, a 1 mm square light emitting surface × 4) having a structure in which a blue LED element and a yellow phosphor are combined. Known blue LED elements and yellow phosphors can be used.

  The light source 12 adjusts the density of the yellow phosphor so that the emission color satisfies the white range on the CIE chromaticity diagram defined by the law and the S / P ratio is adjusted to 1.5.

  The S / P ratio of the light source 12 is not limited to 1.5. The light source 12 satisfies the white range on the CIE chromaticity diagram specified by the law, and the light source 12 illuminates the peripheral area A2, which will be described later (in this embodiment, the S / P ratio is 2.0). Any light source having an S / P ratio lower than that of the light source (S / P ratio of 1.5 or more) may be used.

  The reason why a light source having a lower S / P ratio than a light source 22 described later (in this embodiment, a light source having an S / P ratio of 2.0) is used as the light source 12 is that the peripheral area A2 is When the central region A1 is irradiated with light emitted from a light source having the same S / P ratio as the light source 22 to be irradiated (for example, a light source having an S / P ratio of 2.0), a feeling of glare (glare) is given to the oncoming vehicle. This is to suppress this.

  The reason why a light source having an S / P ratio of 1.5 or more is used as the light source 12 is that it is difficult to satisfy the white range on the CIE chromaticity diagram defined by laws and regulations when the S / P ratio is smaller than 1.5. It is to become.

  The light source 12 is not limited to a white LED as long as the above conditions are satisfied. For example, the light source 12 may be a halogen bulb having an S / P ratio of about 1.46.

Light source 12 (white LED) has its light emitting surface is mounted on a substrate K in a state facing upward, is disposed at the rear side and the vicinity of the optical axis AX ₁₀ from the vehicle rear side focal point F ₁₁ of the projection lens 11 . White LED12 has its one side a line at predetermined intervals along a horizontal line perpendicular to the optical axis _{AX 10} plurality (e.g., four) (Fig. 24 (a) the direction perpendicular to the middle paper) and the optical axis _{AX 10} They are arranged symmetrically.

The reflecting surface 13, the first focal point F1 is set to the light source 12 near the like at the back focal F ₁₁ reflecting surface of the spheroid system set in the vicinity (spheroid or which after the second focal point F2 is the projection lens 11 A free-form surface).

  The reflection surface 13 extends from the side of the light source 12 (the side on the vehicle rear side in FIG. 24A) toward the projection lens 11 so that light radiated substantially upward from the light source 12 enters. The upper part of the light source 12 is covered.

  FIG. 25A is a front view of the shade 14.

As shown in FIG. 25A, the shade 14 is formed with an opening 14a having a shape corresponding to the central region A1. Side focal point _{F 11} of the projection lens 11 is positioned near the opening 14a.

According to the lamp unit 10 having the above structure, light emitted from the light source 12 is reflected by the reflecting surface 13 and converges at the side focal point F ₁₁ near the rear of the projection lens 14, passes through the opening 14a of the shade 14, further The light passes through the projection lens 14 and is irradiated forward. That is, the illuminance distribution formed by the light from the light source 12 that passes through the opening 14 a of the shade 14 is inverted and projected forward by the action of the projection lens 11. As a result, the central area A1 on the virtual vertical screen (located about 25 m ahead from the front of the vehicle) facing the front of the vehicle is irradiated.

  The lamp unit 10 has its optical axis adjusted by a known aiming mechanism (not shown) so as to irradiate the central area A1.

[Lamp unit 20]
The lamp unit 20 is a projector-type lamp unit that irradiates the peripheral area A2 and the front area A4. As shown in FIG. 24B, the projection lens 21 is disposed on the optical axis AX ₂₀ extending in the vehicle front-rear direction. , so as to shield the portion of the light from the projection lens light source 22 is arranged side focal point F ₂₁ on the rear side and the optical axis AX ₂₀ near the rear 21, the reflective surface 23 is arranged above the light source 22, light source 22 In addition, a shade 24 disposed between the projection lens 21 and the light source 22 is provided.

The projection lens 21 is disposed on an optical axis AX ₂₀ that is held in a lens holder or the like (not shown) and extends in the vehicle front-rear direction. The projection lens 21 is, for example, a plano-convex aspherical projection lens having a convex surface on the front side of the vehicle and a flat surface on the rear side of the vehicle.

  The light source 22 is, for example, a white LED (for example, 1 mm square light emitting surface × 4) having a structure in which a blue LED element B, a red LED element R, and a green phosphor G are combined as shown in FIG. . The green phosphor G covers the blue LED element B and the red LED element R, and is excited by the blue light emitted from the blue LED element B to emit green light. When green light increases, the emission color becomes blue-green, which deviates from the white range on the CIE chromaticity diagram defined by law. Therefore, by adjusting the output by adding the red LED element R, the emission color was adjusted to be within the white range on the CIE chromaticity diagram defined by the law. Known blue LED elements, red LED elements, and green phosphors can be used.

  The light source 22 adjusts the density and the like of the green phosphor so that the emission color satisfies the white range on the CIE chromaticity diagram defined by the law and the S / P ratio is adjusted to 2.0. .

  The S / P ratio of the light source 22 is not limited to 2.0. By irradiating the peripheral area in front of the vehicle with light emitted from a light source having an S / P ratio of 2.0 or more, the perception in the peripheral vision becomes faster in a dark environment during night driving (the reaction speed RT is short). Therefore, the light source 22 may be a light source having a S / P ratio in the range of 2.0 to 3.0. The reason why the S / P ratio 3.0 is set as the upper limit is that when the S / P ratio exceeds 3.0, it is difficult to satisfy the white range on the CIE chromaticity diagram defined by law.

  Based on the correlation between the S / P ratio and the miss rate, the S / P ratio is 2.5 (or 2.5 or more), and based on the knowledge that the difference in awareness due to age disappears (see Experiment 1), S / P By irradiating the surrounding area with light emitted from a light source having a P ratio of 2.5 or 2.5 to 3.0, the vehicle front has no noticeable difference due to age in a dark environment during night driving. An illumination lamp can be configured.

  The light source 22 only needs to be a light source whose emission color satisfies the white range on the CIE chromaticity diagram specified by law and has an S / P ratio of 2.0 or more, and includes a blue LED element, a red LED element, and a green LED element. It is not limited to white LED of the structure which combined the fluorescent substance.

  For example, as shown in FIG. 4B, the light source 22 may be a white LED having a structure in which a blue LED element B and green and red phosphors GR are combined. The green and red phosphors GR cover the blue LED element B, and are excited by blue light emitted from the blue LED element B to emit green and red light. The light source 22 may be a white LED having a structure in which a red LED element, a green LED element, and a blue LED element are combined, or a white LED having a structure in which an ultraviolet or near ultraviolet LED element is combined with an RGB phosphor. There may be. Even in a white LED having such a structure, by adjusting the phosphor concentration or the like, the emission color satisfies the white range on the CIE chromaticity diagram defined by the law, and the S / P ratio is 2. It is possible to configure zero or more light sources.

Light source 22 (white LED) has its light emitting surface is mounted on a substrate K in a state facing upward, is disposed at the rear side and the vicinity of the optical axis AX ₂₀ from the vehicle rear side focal point F ₂₁ of the projection lens 21 . A plurality of (for example, four) white LEDs 22 are arranged in a row (in a direction perpendicular to the inner surface of FIG. 24B) along a horizontal line perpendicular to the optical axis AX ₂₀ on one side thereof and on the optical axis AX ₂₀ . They are arranged symmetrically.

Reflecting surface 23, the first focal point F1 is set near the light source 22, similar to the rear focal point F ₂₁ configured spheroid system of the reflective surface near the (spheroid or which after the second focal point F2 is the projection lens 21 A free-form surface).

  The reflection surface 23 extends from the side of the light source 22 (the side on the vehicle rear side in FIG. 24B) toward the projection lens 21 so that light radiated substantially upward from the light source 22 enters. The upper part of the light source 22 is covered.

  FIG. 25B is a front view of the shade 24.

As shown in FIG. 25B, the shade 24 is formed with an opening 24a having a shape corresponding to the peripheral area A2 and the front area A4. Side focal point _{F 21} of the projection lens 21 is positioned near the opening 24a.

According to the lamp unit 20 having the above structure, light emitted from the light source 22 is reflected by the reflecting surface 23 and converges at the side focal point F ₂₁ near the rear of the projection lens 24, passes through the opening 24a of the shade 24, further The light is transmitted forward through the projection lens 21. That is, the illuminance distribution formed by the light from the light source 22 that passes through the opening 24 a of the shade 24 is inverted and projected forward by the action of the projection lens 21. Thereby, the peripheral area A2 and the front area A4 on the virtual vertical screen (located about 25 m ahead from the front of the vehicle) facing the front of the vehicle are irradiated.

  The lamp unit 20 has its optical axis adjusted by a known aiming mechanism (not shown) so as to irradiate the peripheral area A2 and the front area A4.

[Lamp unit 30]
The lamp unit 30 is a projector-type lamp unit that irradiates the intermediate area A3. As shown in FIG. 24C, the projection lens 31 and the projection lens 31 are arranged on an optical axis AX ₃₀ extending in the vehicle front-rear direction. The projection lens so as to block a part of the light from the light source 32 disposed behind the rear focal point F ₃₁ and in the vicinity of the optical axis AX ₃₀ , the reflecting surface 33 disposed above the light source 32, and the light source 32. A shade 34 disposed between 31 and the light source 32 is provided.

The projection lens 31 is disposed on an optical axis AX ₃₀ that is held in a lens holder or the like (not shown) and extends in the vehicle front-rear direction. The projection lens 31 is, for example, a planoconvex aspherical projection lens having a convex front surface and a flat rear surface.

  The light source 32 is, for example, a white LED (for example, 1 mm square light emitting surface × 4) having a structure in which a blue LED element and a yellow phosphor are combined. Known blue LED elements and yellow phosphors can be used.

  The light source 32 adjusts the density of the yellow phosphor so that the emission color satisfies the white range on the CIE chromaticity diagram defined by the law and the S / P ratio is adjusted to 1.8.

  The S / P ratio of the light source 32 is not limited to 1.8. Based on the knowledge that light sources with a high S / P ratio (especially those with an S / P ratio of 1.8 or more) clarify white, blue, and green (see Experiment 3), the light source 32 has an S / P ratio. May be any light source in the range of 1.8 to 3.0. The reason why the S / P ratio 3.0 is set as the upper limit is that when the S / P ratio exceeds 3.0, it is difficult to satisfy the white range on the CIE chromaticity diagram defined by law.

  The light source 32 only needs to be a light source whose emission color satisfies the white range on the CIE chromaticity diagram specified by law and has an S / P ratio of 1.8 or more, and is a combination of a blue LED element and a yellow phosphor. It is not limited to the white LED of the structure. For example, the light source 32 may be a white LED having another structure.

The light source 32 (white LED) is mounted on the substrate K with its light emitting surface facing upward, and is disposed behind the focal point F ₃₁ on the rear side of the projection lens 31 and in the vicinity of the optical axis AX ₃₀ . . White LED32 has its one side a line at predetermined intervals along a horizontal line perpendicular to the optical axis _{AX 30} plurality (e.g., four) (FIG. 24 (c) the direction perpendicular to the middle paper) and the optical axis _{AX 30} They are arranged symmetrically.

Reflecting surface 33, the first focal point F1 is set near the light source 32, similar to the rear focal point F ₃₁ is set in the vicinity rotational ellipsoidal reflecting surface (spheroid or which after the second focal point F2 is the projection lens 31 A free-form surface).

  The reflecting surface 33 extends from the side of the light source 32 (the side on the vehicle rear side in FIG. 24C) toward the projection lens 31 so that light radiated substantially upward from the light source 32 enters. The upper part of the light source 32 is covered.

  FIG. 25C is a front view of the shade 34.

As shown in FIG. 25C, the shade 34 has an opening 34a having a shape corresponding to the intermediate area A3. Side focal point F ₃₁ of the projection lens 31 is positioned between (substantially middle) between the opening 34a and the left of the opening 34a of the right.

According to the lamp unit 30 having the above structure, light emitted from the light source 32 is reflected by the reflecting surface 33 and converges at the side focal point F ₃₁ near the rear of the projection lens 31, passes through the opening 34a of the shade 34, further The light passes through the projection lens 31 and is irradiated forward. That is, the illuminance distribution formed by the light from the light source 32 that passes through the opening 34 a of the shade 34 is inverted and projected forward by the action of the projection lens 31. Thereby, the intermediate area A3 on the virtual vertical screen is irradiated.

  The lamp unit 30 has its optical axis adjusted by a known aiming mechanism (not shown) so as to irradiate the intermediate area A3.

  As described above, according to the vehicle headlamp 100 having the above-described configuration, the light emitted from the light source 22 having an S / P ratio of 2.0 or more is irradiated to the peripheral area A2 (A2R, A2L) in front of the vehicle. By doing so, it becomes possible to speed up awareness in peripheral vision in a dark environment during night driving.

  Moreover, according to the vehicle headlamp 100 having the above-described configuration, the light is emitted from the light source 12 (S / P ratio of 1.5 or more) having a lower S / P ratio than the light source 22 (S / P ratio of 2.0 or more). Compared with the case where light emitted from a light source having the same S / P ratio as that of the light source 22 (S / P ratio of 2.0 or more) is applied to the central area A1 because the light is applied to the central area A1. It becomes possible to suppress giving a dazzling feeling (glare) to the car.

  Moreover, according to the vehicle headlamp 100 having the above-described configuration, the light is emitted from the light source 22 (S / P ratio of 2.0 or more) having a higher S / P ratio than the light source 12 (S / P ratio of 1.5 or more). Since the light is emitted to the peripheral area A2 (A2R, A2L), the light emitted from the light source having the same S / P ratio as the light source 12 (S / P ratio of 1.5 or more) is transmitted to the peripheral area A2 (A2R, Compared with the case of irradiating to (A2L), it becomes possible to speed up awareness in peripheral vision in a dark environment during night driving.

  As described above, according to the vehicle headlamp 100 configured as described above, it is possible to prevent the oncoming vehicle from being dazzled (glare) and to be viewed in the dark environment during night driving. It becomes possible to speed up the notice.

  Moreover, according to the vehicle headlamp 100 having the above-described configuration, the light source 12 (S / P ratio of 1.5 or more) and the light source 22 (S / P) pass through the intermediate region A3 through which a relatively moving sign passes during traveling. It is possible to irradiate with a light source 33 (S / P ratio 1.8 or more) having an S / P ratio different from the ratio 2.0 or more.

  Moreover, according to the vehicle headlamp 100 having the above-described configuration, the light emitted from the light source 33 having an S / P ratio of 1.8 or more is passed to the intermediate region A3 through which a sign that moves relatively during traveling passes. Irradiation makes it possible to clearly show signs (especially white, blue, and green) in a dark environment during night driving.

  Moreover, according to the vehicle headlamp 100 having the above-described configuration, the light emitted from the light source 22 having an S / P ratio of 2.0 or more is irradiated to the near area A4 arranged below the horizontal line on the virtual vertical screen. By doing so, it is possible to increase the brightness of the front area of the vehicle (area on the road surface in front of the vehicle in the own lane) without increasing the illuminance in a dark environment during night driving.

  Next, a modified example will be described.

  In the above embodiment, the light distribution pattern including the central region A1, the peripheral region A2, the intermediate region A3, and the near region A4 has been described as the light distribution pattern that is quickly noticed in peripheral vision. Is not limited to this. That is, the light distribution pattern that can be noticed quickly in peripheral vision may be a light distribution pattern including at least the peripheral region A2, and the other regions A1, A3, and A4 can be omitted as appropriate. For example, the light distribution pattern that is quickly noticed in peripheral vision may be a light distribution pattern that includes the regions A1, A2, and A4 by omitting the region A3 (omitting the lamp unit 30). In this case, the size of the opening 24a of the shade 24 may be enlarged, and the light from the light source 22 may be irradiated onto the region A3.

  In the above embodiment, projector-type lamp units 10, 20, and 30 are used as optical systems that irradiate the areas A 1 to A 4 with light emitted from the light sources 12, 22, and 32 having different S / P ratios. However, the present invention is not limited to this.

  For example, the optical system that irradiates each of the areas A1 to A4 with light emitted from the light sources 12, 22, and 32 having different S / P ratios may be a reflector-type lamp unit, or a so-called direct projection. It may be a lamp unit of a type (also referred to as a direct-light type).

  FIG. 26A is a cross-sectional view of the reflector type lamp unit 40.

As shown in FIG. 26 (a), a reflector-type lamp unit 40 includes, for example, a parabolic reflecting surface 41 (a rotating paraboloid or a free curved surface similar thereto) including a plurality of small section reflecting surfaces. And the light source 12 disposed at the focal point F ₄₁ of the reflecting surface 41.

  In the reflector-type lamp unit 40, for example, the reflection surface is configured to reflect (distribute) light incident from the light source 12 (S / P ratio of 1.5 or more) in a predetermined direction and irradiate the central region A1. By designing 41 (individual small section reflecting surfaces), it is possible to configure a reflector-type lamp unit that irradiates the central area A1 in front of the vehicle with the light emitted from the light source 12.

  Similarly, a reflector-type lamp unit for irradiating light emitted from the light source 22 (S / P ratio of 2.0 or more) to the peripheral area A2 and the front area A4 in front of the vehicle, and the light source 32 (S / P ratio 1.. It is possible to configure a reflector-type lamp unit that irradiates the intermediate area A3 in front of the vehicle with the light emitted from 8 or more).

  FIG. 26B is a cross-sectional view of the direct projection type lamp unit 50.

As shown in FIG. 26B, the direct projection type lamp unit 50 includes, for example, a projection lens 51 and a light source 12 disposed at a rear focal point F ₅₁ of the projection lens 51.

  In the direct projection type lamp unit 50, for example, the light from the light source 12 emitted from the emission surface 51a of the projection lens 51 is refracted in a predetermined direction to irradiate the central region A1. By designing the emission surface 51a, it is possible to configure a direct projection type lamp unit that irradiates the central region A1 in front of the vehicle with light emitted from the light source 12 (S / P ratio of 1.5 or more). .

  Similarly, a direct projection type lamp unit for irradiating light emitted from the light source 22 (S / P ratio of 2.0 or more) to the peripheral area A2 and the front area A4 in front of the vehicle, and a light source 32 (S / P ratio of 1). .8 or more) can be configured as a direct projection type lamp unit that irradiates the intermediate area A3 in front of the vehicle.

  FIG. 27 shows an example of a light source 52 in which a plurality of white LEDs having different S / P ratios are arranged in a matrix.

  In the direct projection type lamp unit 50, instead of the light source 12 shown in FIG. 26B, a light source 52 in which a plurality of white LEDs having different S / P ratios are arranged in a matrix as shown in FIG. It may be used.

  In FIG. 27, □ is a light source 12 having an S / P ratio of 1.5 or more, Δ is a light source 32 having an S / P ratio of 1.8 or more, and x is a light source 22 having an S / P ratio of 2.0 or more. Each light source 12-32 is arrange | positioned in the position corresponding to each area | region A1-A4 shown in FIG.

  According to this modification, the light emitted from the matrix light source 52 passes through the projection lens 51 and is irradiated forward. That is, the images of the light sources 12 to 32 constituting the matrix are inverted and projected forward by the action of the projection lens 51. Thereby, each area | region A1-A4 (or area | region corresponding to each area | region A1-A4) on a virtual vertical screen is irradiated.

  Also according to this modification, it is possible to achieve the same effects as in the above embodiment.

  The above embodiment is merely an example in all respects. The present invention is not construed as being limited to these descriptions. The present invention can be implemented in various other forms without departing from the spirit or main features thereof.

  DESCRIPTION OF SYMBOLS 100 ... Vehicle headlamp, 10-30 ... Lamp unit, 11, 21, 22 ... Projection lens, 12, 22, 32 ... Light source, 13, 23, 33 ... Reflecting surface, 40 ... Reflector type lamp unit, 50 ... Direct projection type lamp unit, 52 ... Matrix type light source

Claims (3)

In a vehicle headlamp that forms a predetermined light distribution pattern on a virtual vertical screen facing the front of the vehicle,
A first light source, a second light source, a first optical system, a second optical system, a third light source, and a third optical system,
The predetermined light distribution pattern includes at least a central area including an intersection of a horizontal line and a vertical line on the virtual vertical screen, peripheral areas disposed on both sides of the central area on the virtual vertical screen, and the virtual vertical An intermediate region disposed between the central region on the screen and the peripheral region, through which a sign that moves relatively during travel passes,
The first optical system is configured to irradiate the central region with light emitted from the first light source,
The second optical system is configured to irradiate light emitted from the second light source to the peripheral regions respectively disposed on both sides of the central region,
The third optical system is configured to irradiate the intermediate region with light emitted from the third light source;
The first light source is a light source having a lower S / P ratio than the second light source,
The S / P ratio of the first light source is 1.5 or more,
The S / P ratio of the second light source is 2.0 or more;
The S / P ratio of the third light source is 1.8 or more,
The predetermined light distribution pattern further includes a front region arranged below a horizontal line on the virtual vertical screen,
The second optical system is configured to irradiate the peripheral region and the near region with light emitted from the second light source,
The front area is a position of 3 ° down 9.4 ° to the left, 8 ° down 17 ° to the left, 8 ° down 16.7 ° to the right, and 3 ° down 8.3 ° to the right. A vehicle headlamp which is a trapezoidal region surrounded by a straight line connecting the positions of the two or a rectangular region including the trapezoidal region . The vehicle headlamp according to claim 1, wherein the second light source is light emitted from a light source having a S / P ratio of 2.5 or 2.5 to 3.0 . The vehicle headlamp according to claim 1 or 2, wherein an S / P ratio of the third light source is an S / P ratio between the first light source and the second light source.