JP2009032535A - Linear light source device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear light source device capable of emission with high efficiency and locational uniformity without attenuating radiation light of an LED light source with a light guide member. <P>SOLUTION: The light guide member 10 guides incident light from the LED light source into a longitudinal direction X of the light guide member 10, and also has openings 20 in a plurality of numbers to reflect this guided light to an upper face 14, and a plurality of these openings 20 are respectively aligned and arranged dividedly in the longitudinal direction X of the light guide member 10 so that reflected light Lo becomes to have an incident angle of 42° or more on the upper face 14. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a linear light source device. In particular, the present invention relates to a linear light source device for illumination of an image reading device used for a facsimile, a copying machine, an image reader, a bar code lead or the like.

  Conventionally, an external electrode type fluorescent lamp (EEFL) enclosing xenon gas or the like has been used as a light source of an image reading apparatus used for a facsimile, a copying machine, an image reader, a barcode read and the like. This image reading apparatus has a scanning unit including a fluorescent lamp below an image reading surface on which an original is placed, and the fluorescent lamp is arranged such that the direction perpendicular to the direction in which the scanning unit moves is the longitudinal direction. It is mounted in the scanning unit. At the time of image reading when the scanning unit moves, the image reading surface is irradiated with light from a fluorescent lamp, and reflected light from the image reading surface is read by a light receiving element such as a CCD sensor via an optical system. .

  However, the external electrode fluorescent lamp has a cylindrical glass as a whole body, and there is a limit to downsizing. On the other hand, in recent years, light-emitting diodes (hereinafter also referred to as “LEDs”) have increased in output. In addition, the CCD sensor as a light receiving element is also becoming highly sensitive, and has reached a level at which an image can be read sufficiently even when the amount of light is lower than in the past. In other words, combined with the technological advances of higher output of LEDs and higher sensitivity of CCD sensors, attention has been paid to the technology that uses LEDs instead of fluorescent lamps as the light source of image reading devices, which was previously considered impossible. It's getting on.

FIG. 11 shows a schematic configuration of a conventional linear light source device.
The linear light source device includes a light guide member 100 and LEDs. The light guide member 100 has a straight shape extending in the longitudinal direction X as a whole, and an LED as a light source is in close contact with the lower side in the height direction Y. The light guide member 100 has side surfaces 110 and 120 opposed to the thickness direction Z, a lower surface 130 (left lower surface 130a, right lower surface 130b) opposed to the height direction Y, an upper surface (output surface) 140, and opposed to the longitudinal direction X. The end face 150 and end face 160 are configured as a seven-sided body. An inverted trapezoidal hole 170 (parallel light generating means) is formed in the vicinity of the center of the light guide member 100.

  In this structure, the radiated light from the LED is incident from the lower surface 130 of the light guide member 100 and travels in the height direction Y, and is reflected (refracted) by the holes 170 so as to be dispersed in the left-right direction. Change the course to X respectively. The light whose path has changed is re-reflected at the incident surface sides 130a and 130b, travels in the height direction Y, and the light incident at an angle smaller than the critical angle with respect to the output surface 140 is output to the outside. Light incident at an angle greater than the critical angle re-reflects inside the light guide member and travels toward the lower surface. Thereafter, a part of the light transmitted (advanced) in the light guide member is output from the emission surface 140 while being repeatedly reflected between the lower surface 130 and the emission surface 140 in relation to the critical angle.

Here, an arc-shaped concave groove 180 is formed on the lower surface 130 (130a, 130b), and most of the light incident (collised) on the surface of the concave groove 180 is radially reflected and reflected. For this reason, by appropriately setting the dimensions and intervals of the concave grooves 180, the light emitted to the outside from the emission surface 140 can be made uniform in place. Further, since the light incident on the surface of the groove 180 has various incident angles, the total reflection film 190 is usually provided. This is because if the total reflection film is not provided when the dimension in the longitudinal direction X is large, the light reflected by the lower surface 130 (130a, 130b) is less likely to be output from the emission surface 140 in relation to the critical angle.
Such a linear light source device is disclosed in, for example, Japanese Patent Application Laid-Open Nos. 10-276298 and 2000-307807.

However, when the total reflection film is provided, there is a problem that light is attenuated inside the light guide member in the process of repeating reflection between the lower surface 130 and the emission surface 140. The attenuation factor is approximately Ie × R ^N (= light intensity Ie × reflectance R to the Nth power) if the emitted light intensity Ie from the LED, the reflectance R of the reflective film, and the number of reflections are N times, Taking an apparatus in practical use as an example, the reflectance R = 0.92 and the number of reflections N = 3, which is 0.78 (0.92 ³ ) for Ie. Further, for example, an aluminum film is used as the reflective film 190, but the operation of applying the film to the concave groove 180 is complicated and may increase the cost.
JP-A-10-276298 JP 2000-307807 A

  The problem to be solved by the present invention is to provide a linear light source device that can emit light with high efficiency and local uniformity without attenuating the emitted light of the LED light source with a light guide member. .

  In order to solve the above-described problems, a linear light source device according to the present invention includes a long light guide member that emits illumination light from an upper surface, and makes light incident on the light guide member and disposed on any side surface. LED light source. The light guide member guides incident light from the LED light source in the longitudinal direction of the light guide member and has a plurality of openings for reflecting the guided light toward the upper surface. Are characterized by being arranged in a divided manner in the longitudinal direction of the light guide member so that the reflected light has an incident angle of 42 ° or less on the upper surface.

  Further, the light guide member is characterized in that incident light from the LED light source is reflected on the lower surface of the light guide member and then incident on the plurality of openings.

  In addition, the LED light source is disposed at the center position in the longitudinal direction of the light guide member and on the lower surface facing the upper surface, and the light guide member guides light incident from the LED light source to the light guide. A central reflection hole that divides and reflects at both ends in the longitudinal direction of the member, and a plurality of openings that reflect the light reflected by the central reflection hole toward the upper surface extends over almost the entire area in the longitudinal direction. It is characterized by being divided and divided.

  Since the linear light source device according to the present invention is provided with a plurality of openings instead of using a reflection film, attenuation during light transmission can be avoided and the problem of work of applying the reflection film and an increase in cost can be solved.

FIG. 1 is an overall external view of a linear light source device (hereinafter also referred to as “light source device”) according to the present invention, and is a schematic diagram for explaining an optical principle.
The light source device includes a light guide member 10 and LEDs. The light guide member 10 has a long shape extending in the longitudinal direction X, and an LED serving as a light source is disposed at the center in the longitudinal direction X and below the height direction Y. The light guide member 10 has a side surface 11 and a side surface 12 that face each other in the thickness direction Z, a lower surface 13 in the height direction Y, and an emission surface (upper surface) 14 that faces the lower surface 13. It has an end face 15 and an end face 16 that face each other in the longitudinal direction X, and the whole forms a long shape having a hexagonal cross section. Further, a substantially inverted mountain-shaped parallel light generating means 17 (hole 171) extending from the side surface 11 to the side surface 12 is formed at the center of the light guide member 10, and the center in the longitudinal direction X of the hole 171 corresponds to the LED. ing. The light guide member 10 is made of a transparent plastic member such as an acrylic resin such as PMMA, and has a function of transmitting the emitted light of the LED.

  In the light guide member 10, a plurality of openings 20 are arranged in a line in the longitudinal direction X of the light guide member and to the left and right from the hole 171. The opening 20 is, for example, a rectangular cross section and is an opening extending from the side surface 11 to the side surface 12 like the hole 171, and is smaller than the hole 171.

  FIG. 2 is a schematic diagram for explaining the optical principle of the optical apparatus of FIG. 1 is a perspective view, whereas FIG. 2 shows a front view. The emitted light from the LED is reflected in the left-right direction by the paraboloid 17a and the paraboloid 17b, which are the interfaces of the holes 171. In the drawing, the light reflected in the left direction is indicated as light La, and the light reflected in the right direction is indicated as light Lb. Note that the light Lc that has passed through the center lower interface 17c of the hole 171 goes straight through the hole 171 and is transmitted again into the light guide member 10 above. Thus, by devising the incident surface shape (angle) of the hole 171 depending on the relationship between the refractive index of the light guide member 10 and the refractive index of air, the emitted light from the LED is reflected by the hole 171 or It can be transmitted. Hereinafter, the light La reflected to the left side by the hole 171 and the light Lb reflected to the right side basically have the same optical principle. Therefore, in this embodiment, the light Lb reflected to the right side will be described. .

  The light Lb travels substantially parallel to the emission surface 14 toward the right end surface 16 of the light guide member 10. And when it collides with one of the openings 20, the light Lb is reflected (refracted) toward the exit surface 14 due to the refractive index of the light guide member 10, the refractive index of air, and the shape of the opening 20. .

  FIG. 3 is a diagram for optically explaining the progress of incident light in the opening 20. The light Li that enters the opening 20 from the acrylic portion that is the light guide member is totally reflected by the incident surface 201 of the opening 20 and proceeds as reflected light Lo. Since the opening 20 is a hole provided in the light guide member, the entrance surface and the exit surface become the inner peripheral surface of the hole. Here, the expressions “incident light Li” and “emitted light Lo” mean that light passes from the acrylic part, which is the light guide member, to the air, which is the opening, between substances having different refractive indexes. The expression “incident” and “exit” is used from the meaning of

  Here, when the incident angle A formed by the incident light Li and the incident surface 201 is larger than the critical angle, the incident light Li is totally reflected by the incident surface 201. When the incident angle A is smaller than the critical angle, a part of the incident light Li is reflected by the incident surface 201, but a part of the incident light Li passes through the incident surface 201 and travels in the air. At this time, most of the light traveling in the air is transmitted through the exit surface 204 of the opening 20 and travels as light Lop. Therefore, in order to reflect the incident light by using the opening provided in the light guide member 10, the incident angle on the incident surface of the opening must be designed to be larger than the critical angle.

  Since the incident light Li (Li1, Li2) with respect to the opening 20 is light reflected in parallel from the hole 17 as described with reference to FIG. 2, the light Lo (Lo1, Lo2) reflected by the incident surface 201 of the opening 20 Will basically reflect all at the same angle. That is, in the figure, for convenience of explanation, the light beam is shown as an arrow, but it actually travels as a light beam. Here, as a numerical example of the critical angle, the refractive index of acrylic is approximately 1.5, and the critical angle when exiting from the light guide member into the air is approximately 42 °. Therefore, if the angle A in the figure is larger than 42 °, almost all of the incident light Li can be reflected as the reflected light Lo. Further, by setting the angle A to 45 °, it can be reflected as light perpendicular to the emission surface.

  Returning to FIG. 2, the openings 20 (20 a, 20 b, 20 c, 20 d, 20 e, 20 f, 20 g, 20 h, 20 i, 20 j, 20 k, 20 l) are aligned from the vicinity of the center of the light guide member 10 toward the end surface 16. Therefore, the reflected light at each opening radiates almost uniformly from the exit surface 14 of the light guide member 10. For convenience of explanation, twelve openings 20 are shown, but in actuality, the light guide members 10 are arranged in almost the entire region in the longitudinal direction X. Specifically, the rightmost end 203 of the opening 20a and the leftmost end 202 of the opening 20b are almost in the same position in the longitudinal direction X (displaced in the height direction Y). They are aligned as if the leftmost and rightmost edges coincide.

  FIG. 4 is a diagram for optically explaining how the reflected light Lo from the opening 20 travels with respect to the upper surface 14 of the light guide member 10. In order for the light Lo traveling through the light guide member 10 to penetrate through the upper surface 14 of the light guide member 10 into the external space (light Lo ′), the critical angle B of the light Lo on the upper surface 14 must be 42 ° or less. This is because the light Lo is reflected on the upper surface 14 when the critical angle is 42 ° or less. For this reason, as light is transmitted through the light guide member, the light intensity is reduced. Therefore, the inclination angle of the opening 20 or the shape of the incident surface 201 must be designed so that the reflected light Lo collides with the upper surface at a critical angle of 42 ° or less.

  As described above, the light source device of the present invention uses the lower surface 13 of the light guide member 10 to guide the incident light from the LED to the exit surface of the light guide member (structure shown in FIG. 11). The optical system in terms of light travel is completely different. As a result, in the conventional structure shown in FIG. 11, the inclination angle of the lower surface 13 is limited by the relationship between the dimension in the longitudinal direction X of the light guide member 10 and the dimension in the height direction Y. Therefore, it is difficult to design the critical angle necessary for reflecting light only by the inclination angle of the lower surface. Therefore, in the structure shown in FIG. 11, a groove or a reflective film is provided on the lower surface of the light guide member 10. There was a need. On the other hand, the light source device of the present invention can set the inclination angle of the incident surface 201 of the opening 20 without being limited to the overall size of the light guide member 10, and thus restricts the reflection direction only by the inclination angle of the opening 20. Therefore, it is not necessary to provide the opening 20 in a concave groove or a reflection film, and therefore, it is possible to solve problems such as attenuation associated with light transmission, complication of reflection film application, and cost increase.

  The present invention has an emission surface 14 as an upper surface, and an LED is disposed in proximity to any of the other side surfaces, that is, the lower surface 13, the end surface 15, the end surface 16, the side surface 12, or the side surface 13. . The openings 20 are aligned in a divided manner along the longitudinal direction X of the light guide member 10.

  FIG. 5 shows another embodiment of the light source device according to the present invention. (A) The position where the LED is installed is one of the ends of the long light guide member 10, and (b) is the position where the LED is installed at both ends of the long light guide member 10. This point is different from the light source device shown in FIGS. In (a), LED is arrange | positioned at the lower surface 13 by the side of the end of the light guide member 10 (end surface 15 in FIG. 1). In this embodiment, instead of the end face 15, a deformed end face 172 as the parallel light generating means 17 is formed. The end surface 172 plays the same role as the hole 171 in FIG. 1 and reflects the emitted light from the LED toward the end surface 16 on the opposite side of the light guide member 10 in parallel with the emission surface 14. Therefore, the shape of the end face 171 is devised so that the radiated light of the LED is totally reflected in relation to the critical angle, and the reflected light is parallel to the emission face 14. Then, the parallel light reflected by the end face 17 1 is sequentially totally reflected at the interface of the opening 20 and is output (radiated) from the emission surface 14. This is the same as the optical principle described with reference to FIG. The advantage of this structure compared to the structure shown in FIG. 1 is that the LED is disposed at the end of the light guide member 10, so that, for example, when incorporated in an image reading apparatus, The arrangement relationship can be designed easily, or the cooling member can be arranged easily.

In (b), LEDs are both ends of the light guide member 10 (end surface 15 and end surface 16 in FIG. 1), and are disposed on the lower surface 13, respectively. In this embodiment, instead of the end face 15 and the end face 16, a deformed end face 173 and end face 174 are formed. The end surface 173 and the end surface 174 play the same role as the hole 171 in FIG. 1 and reflect the emitted light from the LED toward the center of the light guide member 10 and in parallel with the emission surface 14. is there. Specifically, the light reflected by the end surface 173 travels from the end surface 173 toward the center of the light guide member 10, and the light reflected by the end surface 174 travels from the end surface 174 toward the center of the light guide member 10. The shapes of the end surface 173 and the end surface 174 are devised so that the emitted light of the LED is totally reflected in relation to the critical angle, and the reflected light is parallel to the emission surface 14. Then, the parallel light reflected by the end face 173 and the end face 174 is sequentially totally reflected at the interface of the opening 20 and is output (radiated) from the emission surface 14. This is the same as the optical principle described with reference to FIG. The advantage of this structure compared to the structure shown in FIG. 1 is that the LED is arranged at the end of the light guide member 10 as in (a) above. The arrangement relationship with other components can be easily designed. Moreover, although the number of LED components increases, the light output from the exit surface 14 can be made more uniform in the longitudinal direction of the light guide member 10.

  Note that the number of LEDs is not limited to one or two, and three or more LEDs may be arranged. Further, the position of the LED is not limited to the end portion or the center portion of the long light guide member 10, and can be arranged at other locations.

  FIG. 6 shows another embodiment of the light source device according to the present invention. FIG. 6 describes the structure of one embodiment viewed from three directions as shown in (a), (b) and (c). The difference between this embodiment and the light source device described in FIG. 1, FIG. 2, and FIG. 5 is that the light source device of FIG. 1, FIG. 2, and FIG. The LED is disposed on the side surface 11 of the light guide member. (A) is drawing (front view) seen from the side surface 11 of the light guide member 10, and shows the same direction as FIG. 2 or FIG. (B) is sectional drawing which looked at the bb cross section of (a) in the arrow direction, and shows only the vicinity of LED. (C) is sectional drawing which looked at the cc cross section of (a) in the arrow direction.

  The LED is disposed on the side surface 11 of the light guide member 10 at the center in the longitudinal direction X and the center in the height direction Y. Therefore, the emitted light of the LED is emitted toward the opposite side surface 12 of the light guide member 10. Parallel light generating means 17 that reflects the emitted light of the LED in the longitudinal direction of the light guide member 10 is formed on the side surface 12 that faces the LED. In this embodiment, the parallel light generating means 17 is a concave portion 175 having a substantially ant hell shape. The interface of the recess 175 is formed so as to totally reflect the emitted light of the LED in relation to the critical angle and to proceed in parallel with the emission surface 13 in the longitudinal direction of the light guide member 10. This point is different in shape, but the optical concept is the same as the hole 171 shown in FIG. 1 and the end face 172, end face 173, and end face 174 shown in FIG.

  The advantage of this embodiment is that the LED is in close contact with the light guide member 10, so that the emitted light of the LED can be guided into the light guide member with a higher probability. Supplementally, in the structure shown in FIG. 1 and the like, the dimension of the light guide member 10 in the thickness direction Z is generally smaller than the dimension of the LED, so that all of the emitted light of the LED is guided to the light guide member 10. I'm not.

  The embodiment shown in FIG. 6, that is, the embodiment in which LEDs are arranged on the side surface of the light guide member 10, and the embodiment shown in FIG. 5, that is, the LEDs are arranged at the end in the longitudinal direction X of the light guide member 10. It is also possible to arrange LEDs at the end portions in the longitudinal direction X by combining the forms, that is, on the side surface 11 of the light guide member 10.

  The LED is not limited to the lower surface 13, the side surface 11, or the side surface 12 of the light guide member 10, but can be provided on the end surface 15 or the end surface 16. In this case, a means for guiding the emitted light in the longitudinal direction of the light guide member 10 is not necessary. However, when the emission region of the LED is smaller than the size of the end face of the light guide member, the emitted light of the LED is not In order to spread in the light guide member, means for generating parallel light is required. For this reason, the LED can be provided on any side surface other than the emission surface 14 of the light guide member 10. The side surface referred to here is not the narrow side surface 11 and the side surface 12 described in the above embodiment, but a wide side surface including the end surface 15, the end surface 16, and the lower surface 13. When the longitudinal direction X of the light guide member 10 is longer than the emission area, it is possible to place an LED at the end of the emission surface 14 (upper surface), but the document is above the emission surface 14. Since the table and the like are arranged close to each other, it is practically impossible to arrange the LEDs on the emission surface 14 side.

  FIG. 7 is a light source device according to the present invention, and shows a valuation of the opening 20. As shown in the figure, the light emitted from the exit surface can be made more uniform by making the entrance surface into a finer step shape.

  The light guide member is a transparent plastic member, and acrylic is shown in the above embodiment. However, the property required of the light guide member is that it can withstand the heat generation of the internal electronic components when incorporated in the image reading apparatus. It is required from the viewpoint that the critical angle can be selected from a certain range in relation to the heat resistance, the long shape, and the workability to the extent that the opening can be processed with high accuracy, the strength resistance, and the refractive index of air. Specifically, polycarbonate and the like are applied in addition to acrylic. However, acrylic is superior to other materials in that it has high transparency, high refractive index and high impact resistance, and can easily form a complicated shape by thermoplastic formation.

  FIG. 8 shows LEDs used in the light source device according to the present invention. The LED has a blue LED element 31 inside a package 30 made of resin, and a phosphor layer 32 is disposed on the front side of the blue LED element 31 in the radial direction. The blue LED element 31 and the phosphor layer 32 are fixed inside the package 30 by the molding agent 33 and are blocked from the outside of the package 30. A bonding agent 34 with the light guide member 10 is provided on the front surface in the radial direction of the phosphor layer 32. In such a configuration, when light having a wavelength of 400 to 415 nm is emitted from the blue LED element 31, the phosphor layer 32 converts the light into visible light having a wavelength of 420 to 640 nm. Is transmitted to. The bonding agent 34 is a translucent and adhesive substance, and for example, silicone is used. Only one blue LED element 31 may be arranged inside the package 30, or a plurality of blue LED elements 31 may be arranged. In this case, not only the amount of light increases, but if there is only one, there will be variations in the amount of light emission, so a design with a margin is required. Can be produced. As the blue LED element 31, for example, an InGaN high-power ultraviolet light emitting diode is used. In the above embodiment, the “LED” is not a blue LED element but includes a package, a phosphor layer, a bonding agent, and the like, but is not necessarily limited to having all the configurations shown in FIG.

  Here, as an example of the dimensions of the light guide member 10, the dimension in the length direction X is 300 mm, the dimension in the height direction Y is 25 mm, and the dimension in the thickness direction is 3 mm. These numerical values are examples, and normally, the dimension in the length direction X is 325 ± 25 mm (A4 size), the dimension in the height direction Y is 30 ± 10 mm, and the dimension in the thickness direction is 3 ± 3 mm. However, this numerical range is also an example, and the present invention does not exclude designs outside the range of the numerical range. In addition, in the case of the rectangle shown in FIG. 3, the dimension in the longitudinal direction is selected from the range of 3 to 7 mm, for example, 5 mm, and the dimension in the lateral direction is 0.5 to 1.0 mm. For example, 0.8 mm. Further, about 40 to 60 openings are arranged in the longitudinal direction X of the light guide member 10. In particular, although the dimension of the longitudinal direction of the opening 20 is mentioned later, it is changing also in the same light guide member by the position. An example of LED dimensions is 10 mm in length and width and 2 mm in height. For example, white light of 160 lumens is output.

  FIG. 9 shows a perspective view of another embodiment of the light source device according to the present invention. This embodiment is different from the embodiment described with reference to FIG. 1 and the like in that the light source device of FIG. 1 transmits the light emitted from the LED toward the end face of the light guide member and in parallel with the emission surface. In contrast, in the present invention, the radiated light from the LED travels toward the lower surface 13 of the light guide member 10 and is reflected using the interface of the lower surface 13, and then the interface of the opening 20 is used. Thus, the light is totally reflected toward the emission surface 14 and output from the emission surface. The light source device shown in FIG. 9 arranges LEDs on the side surface of the light guide member, and is not shown in the figure, but on the opposite side surface of the light guide member, as in the light source device shown in FIG. A substantially ant hell-shaped recess is formed at the opposing position. An opening 18 having a shape different from that of the rectangular opening 20 is formed in the vicinity of the LED. This opening 18 is used to satisfactorily emit light emitted in the vicinity of the light guide member. The optical action of the opening 18 will be described later.

  In FIG. 9, the light source device includes a light guide member 10 and LEDs. The light guide member 10 has a long shape extending in the longitudinal direction X, is the center of the longitudinal direction X, and the LED is disposed on one side surface 11. The light guide member 10 has a side surface 12 facing the side surface 11 in the thickness direction Z, and has a lower surface 13 and an output surface 14 facing the lower surface 13 in the height direction Y. Furthermore, the longitudinal direction X has an end face 16 that faces the end face 15, and the whole forms a long shape with a rectangular cross section.

  In the center of the light guide member 10, a plurality of aperture groups 18 extending from the side surface 11 to the side surface 12 are formed, and in the center of the lower surface 13 of the light guide member 10, a concave portion 131 that draws a gentle paraboloid is formed. Further, a slope 151 and a slope 161 are formed on the end face 15 and the lower face 13 side of the end face 16, respectively. The light guide member 10 is made of, for example, a transparent plastic member made of an acrylic resin such as PMMA, and has a function of transmitting the emitted light of the LED while reflecting it using an interface. The interface here refers to the lower surface 13 (including the recess 131), the end surface 15, the inclined surface 151, the end surface 16, the inclined surface 161, the opening 20, the opening group 18, and the emission surface 14.

  FIG. 10 is a drawing for explaining the optical locus of the light source device shown in FIG. 9, that is, the path of light emitted from the LED, and shows a front view of the light source device shown in FIG. . The drawing illustrates the right half of the light guide member 10 for convenience of explanation, and shows typical light L (L1 to L9) as a course pattern. This is because it is difficult to decipher if the optical trajectory is expressed in a complicated manner.

  The opening 18 formed in the center of the light guide member 10 is mainly an opening for changing the light emitted from the LED in the longitudinal direction of the light guide member. In this embodiment, the opening 18 is directly above the LED. A V-shaped opening 181 is formed, a rectangular opening 182 formed on both sides of the LED, a deer horn-shaped opening 183 disposed obliquely above the LED, and a branch from the opening 183. A branch-shaped opening 184 is formed. These openings 18 are also for efficiently using the emitted light of the LED. Incidentally, the opening 20 is an opening formed in an end region of the opening 18 and basically has a function of totally reflecting incident light and emitting it from the emission surface 14. Since all the openings 20 have the same function, they are expressed by the same number.

  The light L <b> 1 is light emitted toward the upper region of the light guide member, that is, the emission surface 14. The light L1 emitted from the LED collides with the V-shaped opening 181, but travels straight through the opening 181 with almost no reflection at the incident surface (interface) of the opening 181. This is because the incident angle of the light L1 with respect to the incident surface of the opening 181 is smaller than the critical angle when passing through the interface between the acrylic portion of the light guide member 10 and the air of the opening 181. Further, even when the light L1 enters the acrylic portion from the exit surface of the opening 181, the light L1 passes through the acrylic portion with almost no reflection and is output from the upper surface (exit surface 14) of the light guide member. In other words, it may be considered that the light L1 is radiated from the LED substantially straightly above.

  Note that the principle of reflection and transmission of incident light in the opening 181 can be referred to FIG. 3 and the explanation thereof. Further, although the entrance surface and the exit surface of the opening 181 are not shown in FIG. 10, this point can also be referred to FIG. Furthermore, the emitted light of the LED is originally radiated from the side surface 11 toward the opposite side surface (thickness direction Z in FIG. 9). As described above, a substantially ant hell-shaped recess is formed, and the path of the radiated light is changed in the upward direction in the figure by this recess. Thereafter, also in the light L2 to the light L9, the light radiated from the LED is originally radiated from the side surface 11 to the side surface 12 of the light guide member 10 (direction Z in FIG. 9). The course is changed in the two-dimensional direction of the paper (two-dimensionally formed by the direction X and the direction Y in FIG. 9).

  The light L2 is also light emitted toward the upper region of the light guide member, that is, the emission surface 14, but the difference from the light L1 is that the light L2 is emitted slightly diagonally upward rather than directly above the LED. is there. Specifically, the emitted light of the LED collides with the opening 181, but hardly reflects on the incident surface of the opening 181, travels straight like the light L <b> 1, and is finally emitted from the emitting surface 14. . However, due to the V shape of the opening 181, the light L <b> 2 is incident at an angle (from an oblique direction) with respect to the incident surface of the opening 181 compared to the light L <b> 1. The light emitted from the light is also output in a refracted form. Thus, the light radiated from the LED toward the upper side of the light guide member is radiated from the region S <b> 1 so as to spread on the emission surface 14 due to refraction by the V shape.

  The light L3 is light emitted toward the right side of the light guide member, that is, toward the end surface 16 and collides with the opening 182. When the light L <b> 3 passes through the incident surface of the opening 182 from the acrylic portion of the light guide member 10, almost all of the light L <b> 3 is reflected and changes its path toward the upper side of the light guide member 10. This is because the incident angle of the light L3 with respect to the incident surface of the opening 182 is larger than the critical angle. The light whose path has been changed travels straight through the opening 183 with almost no reflection and is output from the exit surface 14. This is because, in the opening 183, the incident angle of the light L3 with respect to the incident surface is smaller than the critical angle. As described above, the light L3 is representatively described as light totally reflected by the opening 182 and is emitted from the region S2 of the emission surface 14 of the light guide member 10.

  Similarly to the light L1 and the light L2, the light L4 is light emitted toward the upper side of the light guide member, and the emitted light from the LED first collides with the opening 181. Here, unlike the light L1 and the light L2, the light L4 is totally reflected on the incident surface of the opening 181 and changes its course in the right direction in the drawing. This is because the incident angle with respect to the incident surface when the light L4 passes through the opening 181 is larger than the critical angle. The light L4 whose path has been changed then collides with the opening 184. The collided light L4 is also totally reflected at the incident surface of the opening 184 and is changed in the upward direction at the opening 184, and finally outputted from the emitting surface 14. This is because the incident angle of the light L4 on the incident surface is larger than the critical angle. In this way, the light L4 is representative of the light that is totally reflected at the opening 181 and the opening 184 and is emitted to the outside, and is emitted from the region S3 of the emission surface 14 of the light guide member 10.

  The light L5 is light radiated toward the right region of the light guide member, that is, the end face 16, like the light L3. However, the point different from the light L 3 does not collide with the opening 182 but collides with the opening 20. The collided light L5 is totally reflected at the incident surface of the opening 20, changes its path toward the upper side of the light guide member 10, and is finally output from the output surface 14. This is because when the light L5 passes through the incident surface of the opening 20, the incident angle with respect to the incident surface is larger than the critical angle. As described above, the light L5 does not collide with the other openings (opening 18, lower surface 13, and slope 161), and the light L5 first strikes the opening 20 and is totally reflected at the opening 20. Is representative of the light emitted outside, and is emitted from the region S43 of the exit surface 14 of the light guide member 10.

  The light L6 is light emitted toward the lower region of the light guide member, that is, the lower surface 13. The light L6 radiated from the LED is totally reflected by the recess 131 on the lower surface 13 and changes its path upward. The light L <b> 6 whose path has been changed collides with the opening 20, is totally reflected by the opening 20, changes its path toward the upper side of the light guide member 10, and is output from the emission surface 14. This is because the angle at which the light L6 is incident on the acrylic surface in the recess 131 is larger than the critical angle, and the incident angle on the incident surface is also larger than the critical angle in the opening 20. In this way, the light L6 is a light emitted from the LED as a result of the total reflection of the emitted light from the LED at the concave portion 131 of the lower surface 13 and then the collision of the light with the opening 20 to be totally reflected. And is emitted from the region S5 of the exit surface 14 of the light guide member 10.

  The light L <b> 7 is light emitted toward the lower region of the light guide member, that is, the lower surface 13. The light L7 emitted from the LED is totally reflected by the lower surface 13 (not the recess 131) and changes its path upward. The light L7 whose path has been changed collides with the opening 20 and is totally reflected by the opening 20, thereby changing the path toward the upper side of the light guide member 10, and is finally output from the emission surface 14. This is because the angle at which the light L7 is incident on the lower surface 13 is larger than the critical angle, and the incident angle on the incident surface of the opening 20 is larger than the critical angle. In this way, the light L7 represents the light radiated to the outside by the total reflection of the radiated light from the LED on the lower surface 13 to change the course, and the collision with the opening 20 and the total reflection. It is emitted from the region S6 of the light exit surface 14 of the light guide member 10.

  The light L8 is light emitted toward the upper region of the light guide member, that is, the upper surface 14. The light L8 emitted from the LED collides with the opening 183. The collided light L8 is totally reflected on the incident surface of the opening 183 and changes its path toward the lower side of the light guide member. The light whose path has been changed collides with the lower surface 13, is totally reflected by the lower surface 13, and changes its direction toward the upper side. The light whose path has been changed collides with the opening 20, is totally reflected at the incident surface of the opening 20, and is finally emitted from the emission surface 14. This is because the incident angle with respect to the incident surface is larger than the critical angle when colliding with the incident surface of the opening 183, colliding with the lower surface 13, and colliding with the incident surface of the opening 20. In this way, the light L8 is totally reflected by the reflected light from the LED at the opening 183 and the lower surface 13, and then changes the course by colliding with the opening 20 to be totally reflected. This is representative of emitted light, and is emitted from the region S7 of the exit surface 14 of the light guide member 10.

  The light L9 is light emitted toward the right region of the light guide member, that is, toward the end surface 16, and light emitted toward the lower region of the light guide member, that is, toward the concave portion 131 of the lower surface 13, The former directly shines on the slope 161 of the end face 16, and the latter collides with the slope 161 of the end face 16 after being totally reflected by the recess 131. The light L <b> 9 is totally reflected on the inclined surface 161, changes its path toward the upper side of the light guide member 10, and is output from the emission surface 14. As described above, the light L9 is representative of the light emitted from the LED and totally reflected by the inclined surface 161 to change the course and radiated to the outside. The light L9 represents the region S8 of the light exit surface 14 of the light guide member 10. Is emitted as uniform light.

  As described above, the structure of the present embodiment guides incident light from the LED light source to the lower surface 13 of the light guide member 10 and reflects the light reflected by the lower surface 13 at the plurality of openings 20. It advances toward the emission surface 13 which is the upper surface. The advantage of this structure is that it is not necessary to align the openings 20 along the longitudinal direction of the light guide member 10 and that the openings can be provided at positions where the reflected light from the lower surface 13 can be received.

  Furthermore, as the best mode, the LED light source is disposed at the lower surface 13 at the center position in the longitudinal direction X of the light guide member 10, and the light guide member 10 guides light incident from the LED light source. A plurality of apertures 20 for reflecting the light reflected by the central reflection hole 18 toward the emission surface 14 are provided in the longitudinal direction X. The central reflection holes 18 are divided and reflected at both ends in the longitudinal direction X of the optical member. They are divided and aligned so as to cover almost the whole area in the direction X.

  The fact that the plurality of openings are aligned substantially in the entire region of X in the longitudinal direction of the light guide member 10 is substantially the entire region in relation to the function and effect of the present invention, and not all in a strict sense. Absent.

  The shape, size, arrangement state, and the like of the opening 18 (181, 182, 183, 184) and the opening 20 shown in FIGS. 9 and 10 are only one design example, and various modifications are possible. Here, “total reflection” means light that reflects most of the incident light, and does not reflect 100% in a strict sense.

  In all the embodiments described above, the drawings are expressed to explain the present invention and the optical principle, and the configuration (dimensions and arrangement) on the drawings is not necessarily a design drawing of an actual optical locus. It is not shown. For example, in the drawing, if there is a part where the incident angle is smaller than the critical angle in dimension, the figure explains that the incident angle is larger than the critical angle, if any. For example, it should be interpreted as such, and strict dimensional relation and arrangement relation on the drawing should not be considered.

  In all the above-described embodiments, the light emitted from the LED is described on the assumption that the LED is a point light source. However, in practice, the emission surface of the LED has a finite size. , The emitted light of the LED should not be interpreted as a point light source, but as a surface light source emitted from a finite size.

  As described above, the linear light source device according to the present invention is a long light guide member that emits illumination light from the upper surface, and makes light incident on the light guide member and is disposed on any side surface. The light guide member has a plurality of openings for guiding incident light from the LED light source in the longitudinal direction of the light guide member and reflecting the guided light toward the upper surface. The plurality of openings are arranged in a divided manner in the longitudinal direction of the light guide member so that the reflected light has an incident angle of 42 ° or less on the upper surface. Can be avoided.

  In addition, the light guide member reflects the incident light from the LED light source on the lower surface of the light guide member, and then enters the plurality of openings, thereby regularly aligning the openings 20 in the longitudinal direction of the light guide member. There is no need to be done.

  In addition, the LED light source is arranged at the center position in the longitudinal direction of the light guide member, and is disposed on the lower surface facing the upper surface, and the light guide member transmits light incident from the LED light source in the longitudinal direction of the light guide member. A central reflection hole that divides and reflects at both ends of the direction, and a plurality of openings that reflect the light reflected by the central reflection hole toward the upper surface are divided so as to cover almost the entire area in the longitudinal direction. Therefore, the efficiency of taking in light from the LED light source to the light guide member is high, leading to an increase in the amount of light.

1 shows a linear light source device according to the present invention. The figure for demonstrating the optical principle of the linear light source device which concerns on this invention is shown. The figure for demonstrating the optical principle of the linear light source device which concerns on this invention is shown. The figure for demonstrating the optical principle of the linear light source device which concerns on this invention is shown. 4 shows another embodiment of a linear light source device according to the present invention. 4 shows another embodiment of a linear light source device according to the present invention. The Example of opening of the linear light source device which concerns on this invention is shown. The LED light source of the linear light source device which concerns on this invention is shown. 4 shows another embodiment of a linear light source device according to the present invention. The figure for demonstrating the optical principle of the linear light source device which concerns on this invention is shown. 1 shows a conventional linear light source device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Light guide member 11 Side surface 12 Side surface 13 Lower surface 14 Upper surface 15 End surface 16 End surface 17 Parallel light generation means 20 Opening 201 Opening incident surface 204 Opening exit surface

Claims (3)

In a linear light source device comprising a long light guide member that emits illumination light from the upper surface, an LED light source that is incident on the light guide member and disposed on any side surface of the light guide member, and
The light guide member has a plurality of openings for guiding incident light from the LED light source in the longitudinal direction of the light guide member and reflecting the guided light toward the upper surface,
Each of the plurality of openings is arranged in a line in a divided manner in the longitudinal direction of the light guide member so that the reflected light has an incident angle of 42 ° or less on the upper surface. Light source device.   The linear light source device according to claim 1, wherein the light guide member reflects incident light from the LED light source on a lower surface of the light guide member and then enters the plurality of openings. The LED light source is located at the center position in the longitudinal direction of the light guide member, and is disposed on the lower surface facing the upper surface,
The light guide member has a central reflection hole that divides and reflects light incident from the LED light source at both ends in the longitudinal direction of the light guide member;
2. The linear shape according to claim 1, wherein a plurality of openings for reflecting the light reflected by the central reflection hole toward the upper surface are divided and aligned so as to cover substantially the entire region in the longitudinal direction. Light source device.

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