WO2020241511A1

WO2020241511A1 - Head-up display, method for manufacturing same, and method for manufacturing illuminating device

Info

Publication number: WO2020241511A1
Application number: PCT/JP2020/020370
Authority: WO
Inventors: 裕輝春山; 千秋渋谷
Original assignee: 日本精機株式会社
Priority date: 2019-05-24
Filing date: 2020-05-22
Publication date: 2020-12-03
Also published as: JPWO2020241511A1

Abstract

The purpose of the present invention is to provide an illuminating device that satisfies required quality and can be efficiently manufactured, and efficiently manufacture an illuminating device and the like that satisfy required quality. Disclosed is a head-up display provided with: an illuminating device that has a blue light-emitting diode chip and a phosphor covering the chip, and generates white light; and a display instrument that emits display light by being illuminated by the illuminating device, wherein the wavelength of light emitted from the blue light-emitting diode chip is 452-468 nm inclusive.

Description

Head-up display, its manufacturing method, and lighting equipment manufacturing method

The present disclosure relates to a head-up display, a method for manufacturing a head-up display, and a method for manufacturing a lighting device.

A lighting device that generates white light is used as the light source for the backlight of the display of the head-up display. In such a lighting device, white light is formed by passing blue light emitted by a chip of a blue light emitting diode through a yellow phosphor.

Japanese Unexamined Patent Publication No. 2013-214008

However, in the conventional technology as described above, since the quality is controlled by the required quality in the state of the lighting device, it is difficult to efficiently manufacture the lighting device satisfying the required quality.

Therefore, it is an object of the present disclosure to provide a lighting device that satisfies the required quality and can be efficiently manufactured, and to efficiently manufacture a lighting device or the like that meets the required quality.

On one side, a luminaire having a blue light emitting diode chip and a phosphor covering the chip to generate white light.
It is provided with a display that emits display light when illuminated by the lighting device.
A head-up display is provided in which the wavelength of light output from the chip is 452 nm or more and 468 nm or less.

According to the present disclosure, it is possible to provide a lighting device that satisfies the required quality and can be efficiently manufactured, and to efficiently manufacture a lighting device or the like that meets the required quality.

It is a perspective view which shows the internal structure of the head-up display by one Example from the upper side. It is a figure which shows roughly the vehicle-mounted state of the head-up display in the vehicle side view. It is a perspective view of the TFT panel unit as a single item. It is an exploded perspective view of the TFT panel unit. It is a perspective view of the backlight unit in a single item state. It is an exploded perspective view of the backlight unit. It is a top view which shows an example of one light emitting element body. It is sectional drawing which follows the line AA of FIG. It is a figure which shows the characteristic which concerns on the spectrum of the white light generated by a light emitting element body. It is a figure which shows the characteristic of the color filter of a TFT panel unit. It is a schematic flowchart which shows the outline of the manufacturing method of a light emitting element body. It is a schematic flowchart which shows the outline of the manufacturing method of a head-up display.

Hereinafter, each embodiment will be described in detail with reference to the attached drawings. In addition, in FIG. 1A and the like, for the sake of easy viewing, there are cases where a reference reference numeral is only partially attached to a plurality of parts having the same attribute.

[Head-up display configuration]
FIG. 1A is a perspective view showing the internal configuration of the head-up display 1 according to the embodiment from above. FIG. 1B is a diagram schematically showing a vehicle-mounted state of the head-up display 1 when viewed from the side of the vehicle. Note that in FIG. 1A, the illustration of some components of the head-up display 1 is omitted. In FIG. 1A, the X direction (second direction), the Y direction, and the Z direction (first direction), which are three directions orthogonal to each other, are defined in the right-handed system. In the following, formally, the Z direction is the vertical direction, the positive side is the upper side, and the negative side is the lower side.

The head-up display 1 is mounted in the instrument panel 9 of the vehicle. The head-up display 1 may be mounted in a direction in which the Y direction of FIG. 1A substantially corresponds to the vehicle width direction.

The head-up display 1 includes a case 2, a TFT (Thin Film Transistor) panel unit 3,

mirrors

4 and 5, and a backlight unit 6.

The case 2 forms the housing of the head-up display 1. The case 2 is a lower case that forms the lower part of the housing of the head-up display 1. The case 2 is combined with an upper case (not shown in FIG. 1A).

Case 2 is formed of a highly heat-conducting material such as aluminum. Case 2 includes a heat dissipation portion 21 as shown in FIG. 1A. The heat radiating portion 21 is formed on the outer surface of the case 2 (the surface exposed to the outside). The heat radiating portion 21 has a function of radiating heat generated from the backlight unit 6. The heat radiating portion 21 releases heat to the air flowing outside the case 2.

The TFT panel unit 3 is a display device that uses the light from the backlight unit 6 as a backlight and emits image light according to the display image. The TFT panel unit 3 has a color filter (not shown). The display image is arbitrary, and may be, for example, an image representing navigation information, various vehicle information, and the like.

The TFT panel unit 3 is fixed to the case 2. For example, as shown in FIG. 1A, the TFT panel unit 3 is fastened with screws 90 at two locations on both sides in the X direction.

FIG. 2 is a perspective view of the TFT panel unit 3 in a single item state, and FIG. 3 is an exploded perspective view of the TFT panel unit 3.

The TFT panel unit 3 includes a TFT holder 31, a TFT panel 32, a diffusion sheet 33, and a TFT cover 34. The TFT holder 31 is fixed to the case 2 as described above. The TFT holder 31 holds the TFT panel 32. The TFT panel 32 is a dot matrix type TFT (Thin Film Transistor) panel or the like. The TFT panel 32 is provided so that the long side direction corresponds to the X direction. The TFT cover 34 is fitted and coupled to the TFT holder 31. The TFT panel 32 and the diffusion sheet 33 are held between the TFT cover 34 and the TFT holder 31 in the Y direction.

The

mirrors

4 and 5 reflect the image light emitted from the TFT panel unit 3 and emit the image light (display light) from the outlet provided in the upper case (not shown), and windshield the vehicle VC. Direct to glass WS (an example of a transmission / reflection part). In this embodiment, two

mirrors

4 and 5 are provided, but the number of mirrors is arbitrary. In this embodiment, as an example, the mirror 4 is a flat mirror and the mirror 5 is a concave mirror. The mirror 5 may be rotatably supported with respect to the case 2 so that the vertical position of the area exposed to the image light on the windshield glass WS can be adjusted.

When the windshield glass WS is irradiated with image light, as shown in FIG. 1B, for the driver who drives the vehicle VC, the display image obtained by the irradiation is in front of the windshield glass WS. Virtual image display) VI can be seen. As a result, the driver can visually recognize the display image VI by superimposing it on the front scenery, and can grasp the vehicle information and the like in a mode in which the line of sight movement is small, and the convenience and safety are improved.

The backlight unit 6 is provided behind the TFT panel unit 3 (negative side in the Y direction). The backlight unit 6 cooperates with the TFT panel unit 3 to generate image light. The backlight unit 6 is fixed to the case 2.

[Backlight unit configuration]
FIG. 4 is a perspective view of the backlight unit 6 in a single item state, and FIG. 5 is an exploded perspective view of the backlight unit 6.

The backlight unit 6 includes a light emitting element body 8 (an example of a lighting device). The backlight unit 6 has a function of emitting light from the light emitting element body 8 to the TFT panel unit 3 and transferring the heat generated by the light emitting element body 8 to the heat radiating portion 21.

The backlight unit 6 includes a lens cover 61, a first lens spring 62, a condenser lens 63 (an example of a lens), a diffuser plate 64 (an example of a lens), a lens holder 65, and a second lens spring 66. , A lens array 67 (an example of a lens), a light emitting substrate 68, and a control substrate 69.

The lens cover 61 covers the front surface (positive side in the Y direction) of the backlight unit 6. The lens cover 61 has an opening 611 from which the condenser lens 63 is exposed. The lens cover 61 is fitted and coupled to the lens holder 65. In this embodiment, as an example, the lens cover 61 has claws 612 extending in the negative direction in the Y direction at four corners, and is fitted and coupled to the lens holder 65 by the claws 612.

The first lens spring 62 is in the form of a leaf spring, and is provided between the lens cover 61 and the condenser lens 63 in the Y direction. The first lens springs 62 are provided in pairs in the vertical direction. Each of the first lens springs 62 is fixed to the upper side and the lower side side surfaces of the lens cover 61. Each of the first lens springs 62 urges the condenser lens 63 together with the diffuser plate 64 toward the lens holder 65. As described above, the first lens spring 62 has a function of defining the positions of the condenser lens 63 and the diffuser plate 64 in the Y direction with respect to the lens holder 65.

The diffuser plate 64 and the condenser lens 63 diffuse and collect the light from the light emitting element body 8 that is incident through the lens array 67 toward the front surface (positive side in the Y direction) of the backlight unit 6. It has a function of emitting light. The diffusion plate 64 is, for example, a plate shape formed of a translucent resin material and having at least one surface subjected to fine unevenness processing.

The diffuser plate 64 and the condenser lens 63 are held on the positive side of the lens holder 65 in the Y direction. For example, the diffuser plate 64 and the condenser lens 63 each have through holes 641,631 through which the pin portion 650 of the lens holder 65 passes, and the positions in the Z direction and the X direction with respect to the lens holder 65 are defined.

The lens holder 65 holds the diffuser plate 64 and the condenser lens 63, and also holds the lens array 67. The lens holder 65 is fixed to the case 2. The backlight unit 6 is fixed to the case 2 by fixing the lens holder 65 to the case 2.

The second lens spring 66 is in the form of a leaf spring and is fixed to the lens holder 65. The second lens spring 66 has a function of urging the lens array 67 toward the light emitting substrate 68.

The lens array 67 is formed of a translucent resin material and is arranged so as to cover the positive side of the light emitting substrate 68 in the Y direction. The lens array 67 includes a collimator portion 671 having a conical convex outer peripheral surface obtained by rotating a substantially parabolic disconnection. The lens array 67 is located so as to face the light emitting element 8 mounted on the light emitting substrate 68, and transmits the light radiated from the light emitting element 8 to the positive side in the Y direction. The outer shape of the lens array 67 is a rectangle (a rectangle whose long side is in the X direction) that is substantially the same as the outer shape of the TFT panel unit 3 (and the TFT panel 32).

The light emitting substrate 68 is provided behind the lens array 67 (on the negative side in the Y direction). A plurality of light emitting element bodies 8 are mounted in an array on the surface of the light emitting substrate 68 on the side facing the lens array 67. Each light emitting element 8 is one or a plurality of LEDs (Light Emitting Diodes). The arrangement method and number of the light emitting element bodies 8 are arbitrary. The light emitting element body 8 is provided so that the optical axis direction (Y direction) is perpendicular to the light emitting substrate 68.

The control board 69 is electrically connected to the light emitting board 68 and controls the lighting of a plurality of light emitting element bodies 8 provided on the light emitting board 68.

Although the head-up display 1 having a specific configuration is shown above, the present embodiment can be applied to a head-up display having an arbitrary structure as long as the light emitting element body 8 is provided. For example, in the above description, the

mirrors

4 and 5 are provided, but one or both of the

mirrors

4 and 5 may be omitted.

[Structure of light emitting element body]
FIG. 6 is a plan view showing an example of one light emitting device body 8, and FIG. 7 is a cross-sectional view taken along the line AA of FIG. Hereinafter, unless otherwise specified, one light emitting device 8 will be described.

As shown in FIGS. 6 and 7, the light emitting device 8 includes a chip 80 and a phosphor 82. The chip 80 is a blue light emitting diode chip (die). The phosphor 82 is, for example, a YAG (Yttrium aluminum garnet) -based yellow phosphor that covers the chip 80. The phosphor 82 may be formed of a resin containing the phosphor. Further, the phosphor 82 is a β-sialon (SiAlON) -based green phosphor and a CASN (or SCASSN or 1113 phosphor) or KSF-based red phosphor instead of the yellow phosphor. And may be mixed. The light emitting element body 8 also has a substrate 81, a reflective material 84, and the like.

According to such a light emitting element body 8, the blue light emitted from the chip 80 becomes white when passing through the phosphor 82, and white light is emitted.

FIG. 8 is a diagram showing the characteristics related to the spectrum of the white light generated by the light emitting device 8, and the horizontal axis represents the wavelength and the vertical axis represents the relative emission intensity, and the characteristics are shown.

In this embodiment, the white light generated by the light emitting element body 8, that is, the white light output from the chip 80 of the blue light emitting diode via the phosphor 82, preferably has a wavelength of 444 nm, as shown in FIG. It is 460 nm or less. In this case, high-quality white light with less yellowness is obtained, and the display quality of the head-up display 1 can be improved.

In addition, in the relationship between one light emitting element body 8 and another light emitting element body 8, the phosphor 82 for converting the blue light from the chip 80 of the blue light emitting diode into white light is the same individual. If this is the case, the relationship between the wavelength of blue light from the chip 80 of the blue light emitting diode and the wavelength of white light obtained through the phosphor 82 is the same. That is, if the phosphor 82 is the same, the wavelength of blue light from the chip 80 of the blue light emitting diode and the wavelength of white light obtained through the phosphor 82 are in a proportional relationship.

FIG. 9 is a diagram showing the characteristics of the color filter of the TFT panel unit 3. In FIG. 9, the horizontal axis represents the wavelength and the vertical axis represents the transmittance, and the characteristics are shown.

The color filter has a characteristic of transmittance with respect to the wavelength of light, that is, the transmittance increases monotonically as the wavelength increases from 450 nm to 500 nm. The color filter shown in FIG. 9 has a characteristic that the transmittance monotonically increases by at least 3% or more as the wavelength increases from 450 nm to 500 nm.

When such a color filter is used, the transmittance changes relatively significantly within the wavelength range of 444 nm or more and 460 nm, so that the change in the blue transmittance with respect to the change in the wavelength of white light becomes large. Therefore, even if the wavelength of the white light deviates slightly from the desired range, the white light tends to be yellowish.

By the way, each light emitting element body 8 of the backlight unit 6 adjusts a white point (hereinafter, also referred to as “white point adjustment”) so as to realize a desired white light with respect to the light passed through the above-mentioned color filter. And the brightness adjustment (hereinafter, also referred to as "brightness adjustment") are received in order.

The white point adjustment is a process of adjusting the tone of RGB to a desired white color by lowering the tone. The brightness adjustment is a process of raising the brightness reduced due to the white point adjustment to a required level.

By performing such white point adjustment and brightness adjustment, even if the chromaticity in the initial state (before adjustment) is slightly out of the desired chromaticity range, the chromaticity is desired while ensuring the required brightness. It can be kept within the chromaticity range.

However, if the chromaticity in the initial state (before adjustment) deviates relatively greatly from the desired chromaticity range, the brightness decrease after the white point adjustment becomes large. As a result, even if the reduced brightness can be raised to a required level by adjusting the brightness, the current value becomes higher than the specified value, resulting in a defective product.

In this regard, according to the present embodiment, as described above, by limiting the wavelength of the white light generated by the light emitting element 8 to 444 nm or more and 460 nm or less, the decrease in brightness caused by the White point adjustment is suppressed. be able to. As a result, the incidence of defective products can be appropriately reduced.

By the way, in this embodiment, as described above, the white light generated by the light emitting element 8 is generated by passing the blue light emitted from the chip 80 of the blue light emitting diode through the phosphor 82. Therefore, when the white light output from the blue light emitting diode chip 80 via the phosphor 82 has a wavelength of 444 nm or more and 460 nm or less for a certain light emitting element body 8, the cause is only the chip 80. However, there may be other factors such as the phosphor 82 and the like. In general, it is difficult to take out only the chip 80 after covering the phosphor 82 and measure the wavelength of the blue light output from the chip 80.

In view of this point, in this embodiment, the wavelength of blue light output from the chip 80 of the blue light emitting diode is limited to 452 nm or more and 468 nm or less. As a result, the quality control of the light emitting device 8 can be performed in a manner in which other factors (for example, the phosphor 82) are excluded, as compared with the case where the wavelength of the white light obtained through the phosphor 82 is limited. As a result, the backlight unit 6 satisfying the required quality can be efficiently manufactured.

However, also in this embodiment, as a required quality, in addition to limiting the wavelength of blue light output from the blue light emitting diode chip 80 to 452 nm or more and 468 nm or less, the blue light emitting diode chip 80 to the phosphor 82 It may be specified that the wavelength of the white light output via the LED is limited to 444 nm or more and 460 nm or less.

Next, the manufacturing method of the light emitting element body 8 and the manufacturing method of the head-up display 1 will be outlined.

FIG. 10 is a schematic flowchart showing an outline of a method for manufacturing the light emitting element body 8.

The method for manufacturing the light emitting element body 8 includes a first inspection step S1, an assembly step S2, and a second inspection step S3. The first inspection step S1 and the assembly step S2 do not have to be executed in parallel, and may be executed at different places. This also applies to the assembly process S2 and the second inspection process S3, and also applies to the first inspection process S1 and the second inspection process S3.

The first inspection step S1 includes steps from step S100 to step S112.

In step S100, a chip of a blue light emitting diode to be inspected is prepared, and one of them is selected. For example, a plurality of blue light emitting diode chips to be inspected are prepared.

In step S102, blue light is generated from the selected chip, and the wavelength of the blue light is measured.

In step S104, it is determined whether or not the measured value of the wavelength is 452 nm or more and 468 nm or less based on the measurement result obtained in step S102. For example, it is determined whether or not the wavelength at which the peak of the spectrum is 452 nm or more and 468 nm or less. If the determination result is "YES", the process proceeds to step S106, and if not, the process proceeds to step S108.

In step S106, the chip selected in step S102 is determined as a non-defective product.

In step S108, the chip selected in step S102 is determined as a defective product.

In step S110, it is determined whether or not all the chips of the blue light emitting diode to be inspected have been selected. If the determination result is "YES", the process ends, and if not, the process proceeds to step S112.
In step S112, the next one chip is selected from the chips of the blue light emitting diode to be inspected, and the process is repeated from step S104.

The assembly step S2 includes the steps from step S200 to step S202.

In step S200, a chip judged to be a non-defective product in the first inspection step S1 is selected.

In step S202, the light emitting element body 8 is manufactured using the chip selected in step S200. At this time, the chip selected in step S200 becomes a chip 80 that is sealed with a resin containing a phosphor and is covered with the phosphor 82.

The second inspection step S3 includes the steps from step S300 to step S302.

In step S300, another inspection regarding the chromaticity range and the like is performed on the light emitting element body 8 obtained in step S202.

In step S302, only the light emitting element 8 that satisfies the regulation in step S300 is ready to be shipped as a product of a predetermined model number.

According to the manufacturing method shown in FIG. 10, only the blue light emitting diode chip 80 whose measured value of the wavelength of the emitted light is 452 nm or more and 468 nm or less is used as a good product, and the good product chip 80 is used. Only the light emitting element 8 covered with the phosphor 82 can be shipped.

Therefore, if the light emitting device 8 manufactured by the manufacturing method shown in FIG. 10 (that is, the light emitting device 8 to which a predetermined model number is assigned) is used, the measured value of the wavelength of light is 452 nm or more and 468 nm or less. The head-up display 1 can be manufactured by using the light emitting element body 8 which has been inspected before shipment.

FIG. 11 is a schematic flowchart showing an outline of the manufacturing method of the head-up display 1.

In step S400, the light emitting element body 8 to which a predetermined model number is assigned is prepared. That is, the light emitting element 8 manufactured from the chip 80 of the blue light emitting diode whose measured value of the wavelength of the emitted light is 452 nm or more and 468 nm or less is prepared.

In step S402, the backlight unit 6 is assembled using the light emitting element body 8 prepared in step S400.

In step S404, the head-up display 1 is assembled using the backlight unit 6 obtained in step S402.

In step S406, the white point adjustment and the brightness adjustment described above are executed.

In step S408, other necessary inspections and the like are performed, and only the head-up display 1 that meets the regulations can be shipped as a product of a predetermined model number.

According to the manufacturing method shown in FIG. 11, only the chip 80 of the blue light emitting diode whose measured value of the wavelength of the emitted light is 452 nm or more and 468 nm or less can be used for the backlight unit 6. As a result, in the backlight unit 6, the possibility that the decrease in brightness after adjusting the white point becomes large can be reduced, and the yield is improved. Further, even if the current value becomes higher than the specified value as a result of the brightness adjustment and the product becomes defective, the possibility that the blue light emitting diode chip 80 itself is defective can be substantially eliminated, so that it is easy to take measures against defects. Become.

Although each embodiment has been described in detail above, it is not limited to a specific embodiment, and various modifications and changes can be made within the scope described in the claims. It is also possible to combine all or a plurality of the components of the above-described embodiment.

1 Head-up display 2 Case 3 TFT panel unit 4 Mirror 5 Mirror 6 Backlight unit 8 Light emitting element body 9 Instrument panel 21 Heat dissipation part 31 TFT holder 32 TFT panel 33 Diffusion sheet 34 TFT cover 61 Lens cover 62 First lens spring 63 Condensing lens 64 Diffusing plate 65 Lens holder 66 Second lens spring 67 Lens array 68 Light emitting substrate 69 Control substrate 80 Chip 82 Fluorescent film

Claims

A lighting device that has a blue light emitting diode chip and a phosphor that covers the chip and generates white light.
It is provided with a display that emits display light when illuminated by the lighting device.
A head-up display in which the wavelength of light output from the chip is 452 nm or more and 468 nm or less.
The display has a color filter and
The head-up display according to claim 1, wherein the color filter has a characteristic that the transmittance with respect to a wavelength of light increases monotonically by at least 3% or more as the wavelength increases from 450 nm to 500 nm.
The head-up display according to claim 1 or 2, wherein the wavelength of white light output from the chip via the phosphor is 444 nm or more and 460 nm or less.
A lighting device that has a blue light emitting diode chip and a phosphor that covers the chip and generates white light.
It is provided with a display that emits display light when illuminated by the lighting device.
The chip is a head-up display that has been inspected before shipment for a measured value of wavelength of light of 452 nm or more and 468 nm or less.
A lighting device in which the chip of the blue light emitting diode, which has been inspected for the measured value of the wavelength of light of 452 nm or more and 468 nm or less, is covered with a phosphor is prepared.
A method of manufacturing a head-up display, which comprises assembling the lighting device.
The blue light emitting diode chip is inspected to see if the measured value of the wavelength of light is 452 nm or more and 468 nm or less.
The chip of the blue light emitting diode whose measured value of the wavelength of light was confirmed to be 452 nm or more and 468 nm or less by inspection was covered with a phosphor.
A method for manufacturing a lighting device, which comprises classifying the chip covered with the phosphor as a predetermined model number.