JP2003344801A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device which can prevent a display unit from being damaged even if the sunshine is incident and can use an inexpensive cold mirror. <P>SOLUTION: The display unit 11 has 1st pixels emitting red light, 2nd pixels emitting green light, and 3rd pixels emitting blue light. A reflecting member 12 reflects the red light, green light, and blue light. The reflecting member 12 has relatively high reflection factors in a 1st wavelength range including the wavelength of the red light, a 2nd wavelength range including the wavelength of the green light, and a 3rd wavelength range including the wavelength of the blue light and relatively low reflection factors in other wavelength ranges of visible light beams. The reflecting member 12 transmits infrared rays. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device in which display light emitted from a display device is reflected by a reflecting member, and more particularly to a display device using a cold mirror as a reflecting member for reflecting the display light. Is.

[0002]

2. Description of the Related Art Conventionally, a head-up display for displaying a virtual image V by reflecting display light L projected by a display device 2 arranged on a dashboard 1 of a vehicle toward a driver 4 by a windshield 3. Yes (see FIG. 6). The display device 2 has a display device 5, a reflecting mirror 6, and a concave mirror 7. The display device 5, the reflecting mirror 6 and the concave mirror 7 are housed in a housing 8 (see FIG. 7). The display light L emitted from the display 5 is reflected by the reflecting mirror 6, further reflected by the concave mirror 7, and projected on the windshield 3. Driver 4
Can be visually recognized by superimposing the virtual image V on the landscape.

In the above head-up display, sunlight may be reflected by the concave mirror 7 and the reflecting mirror 6 and enter the display 5, and the heat ray of the sunlight may damage the display 5. there were. Therefore, a cold mirror that transmits infrared rays is used as the reflecting mirror 6. The cold mirror is formed by forming a reflective layer (interference film) on a translucent substrate such as a glass substrate by a method such as vapor deposition, and as shown in FIG. 8, it reflects display light (visible light) and heat rays (visible light). Since it has a reflection characteristic of transmitting infrared rays, the infrared rays are not reflected toward the display 5 and the display 5 is not damaged by the heat rays of sunlight.

[0004]

However, the cold mirror has a visible light wavelength range (450 nm to 750 nm).
In order to reflect light of wavelength (nm), a multilayer interference film having a gradually different film thickness is formed by lamination, so that there is a problem that it is very expensive. The present invention has been made in view of this problem, and provides a display device capable of preventing damage to the display even when sunlight is incident and using an inexpensive cold mirror. .

[0005]

In order to solve the above-mentioned problems, the present invention is a display device having a display 11 for emitting display light L and a reflecting member 12 for reflecting the display light L, The reflection member 12 has a reflectance characteristic corresponding to the wavelength characteristic of the display light L. Further, the present invention is a display device including a display device 11 that emits the display light L and a reflection member 12 that reflects the display light L, wherein the reflection member 12 has a wavelength not emitted by the display device 11. The reflectance is low in the range.

Further, according to the present invention, there is provided a display device 11 having a first display portion for emitting a first display light and a second display portion for emitting a second display light, the first display light and the above display light. A display device, comprising: a reflection member 12 that reflects second display light, wherein the reflection member 12 has a first wavelength range including at least the wavelength of the first display light and the second display. The reflectance is relatively high in the second wavelength range including the wavelength of light.

The present invention also provides a display 11 having a first pixel 16R emitting red light, a second pixel 16G emitting green light and a third pixel 16B emitting blue light, and the red light. A display device having a reflective member 12 for reflecting the green light and the blue light, the reflective member 1 comprising:
2 has a high reflectance in the first wavelength range including the wavelength of the red light, the second wavelength range including the wavelength of the green light, and the third wavelength range including the wavelength of the blue light. In other wavelength ranges of visible light, the reflectance is relatively low.

Further, according to the present invention, the reflecting member 12 transmits infrared rays.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which the present invention is applied to a vehicle head-up display will be described below. The display device 10 includes a liquid crystal display 11 (display), a cold mirror 12 (reflecting member), and a reflector 13.
Liquid crystal display 11, cold mirror 12 and reflector 13
Are contained in the housing 14.

The liquid crystal display 11 displays the speed of the vehicle, the number of revolutions of the engine, etc., and has a TFT type liquid crystal display element 16, a reflector 17, a light emitting diode 18, and a hard wiring board 19 ( See FIG. 2). As shown in FIG. 3, the liquid crystal display element 16 includes a red pixel 16R (first pixel), a green pixel 16G (second pixel), and a blue pixel 16B.
It has a (third pixel) and displays the vehicle speed, engine speed, etc. digitally or in a bar graph.

The plurality of light emitting diodes 18 are arranged close to each other and connected to the hard wiring board 19, and emit light in white. The reflector 17 is made of white resin and has a rectangular tube shape. The reflecting member 17 reflects the light emitted from the light emitting diode 18 on the inner peripheral reflecting surface 17a to the liquid crystal display element 16.

The cold mirror 12 is a glass substrate 12a.
And the reflective layer 1 formed on the front surface of the glass substrate 12a.
2b (see FIG. 4). Reflective layer 12b
Is composed of multiple interference films having different film thicknesses and is formed by a method such as vapor deposition. Cold mirror 12
The liquid crystal display 11 is tilted at an angle of about 45 ° with respect to the optical axis of the liquid crystal display 11.

The reflector 13 comprises a concave mirror 21, a mirror holder 22, a gear 23 and a stepping motor 24. The concave mirror 21 reflects the display light L and projects it on the windshield of the vehicle. The concave mirror 21 is adhered to the mirror holder 22 with a double-sided adhesive tape. The concave mirror 21 is formed by depositing aluminum (Al) on a resin such as polycarbonate (PC) to form a reflective layer. The mirror holder 22 is made of resin such as PBT, and the gear portion 22a and the shaft portion 22b are integrally formed. The shaft portion 22b is axially supported by a bearing portion (not shown) provided in the housing 14.

The stepping motor 24 rotates the concave mirror 21 to adjust the projection direction of the display light L. The gear 23 is attached to the rotary shaft of the stepping motor 24,
It is meshed with the gear portion 22a. The driver operates a switch (not shown) to adjust the angle of the concave mirror 21 so that the display light L is reflected at the eye position.

Next, based on FIG. 5, the cold mirror 1
The reflectance characteristic of No. 2 will be described in detail. Cold mirror 12
Is the first wavelength range including red light 450 nm to 480 n
m, second wavelength range including green light 530 nm to 560 n
m, a third wavelength range including blue light 610 nm to 640 n
The reflectance is high at m and is low in other wavelength ranges. In particular, the reflectance is low in the infrared wavelength range, 1
It is below 5%.

The cold mirror 12 has a visible light wavelength range of 450 nm to 750 nm other than the first, second, and third wavelength ranges, that is, 480 nm to 530 nm, 56.
Since the reflectance may be low at 0 nm to 610 nm and 640 nm to 750 nm, the number of the reflection layer 12b interference films can be reduced, and the cold mirror 6 can be manufactured at a lower cost.

In the present embodiment, the cold mirror 12 is arranged in the optical path of the display device 10, so that the heat ray of sunlight does not enter the liquid crystal display 11, and the liquid crystal display 11 is exposed to the heat ray of sunlight. There is no risk of damage. In addition, since it is possible to increase the reflectance at the wavelengths of red light, green light, and blue light emitted from the red pixel 16R, the green pixel 16G, and the blue pixel 16B of the liquid crystal display element 16, respectively, 3
Since the color display light can be reflected efficiently and the reflectance is low in other wavelength ranges, the cold mirror 12 can be used at a low cost.

The present invention focuses on the fact that the cold mirror 12 does not necessarily have a high reflectance over the entire wavelength range of visible light, and the reflectance characteristic of the cold mirror 12 depends on the wavelength characteristic of display light. It has been set.

The liquid crystal display element 16 of this embodiment is
Although it has pixels 16R, 16G, and 16B of three colors, a display element that emits display light of two colors may be used, for example. Further, although the display of the present embodiment is the liquid crystal display 11, for example, an organic electroluminescent display element (organic EL) is used.
It is also possible to alleviate the deterioration of the organic layer due to ultraviolet rays. Further, although the present embodiment is a head-up display in which the display light L is reflected by the windshield to be visually recognized, it goes without saying that the present invention can also be applied to a display device that directly looks at the display light L.

[0020]

The present invention is a display device having a display device for emitting display light and a reflecting member for reflecting the display light, wherein the reflecting member is a reflection member corresponding to the wavelength characteristic of the display light. Since it has a rate characteristic, an inexpensive reflecting member can be used, and there is no risk of damage to the display even when sunlight is incident.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention.

FIG. 2 is a sectional view of a liquid crystal display showing the embodiment.

FIG. 3 is an enlarged view of a liquid crystal display element showing the embodiment.

FIG. 4 is a sectional view of a cold mirror showing the embodiment.

FIG. 5 is a reflectance characteristic diagram of the cold mirror according to the above embodiment.

FIG. 6 is an explanatory diagram of a head-up display showing a conventional example.

FIG. 7 is a schematic configuration diagram showing a conventional example of the above.

FIG. 8 is a reflectance characteristic diagram of a cold mirror showing the conventional example.

[Explanation of symbols]

11 Liquid crystal display (display) 12 Cold mirror (reflection member) 16R First pixel 16G second pixel 16B Third pixel

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H048 FA01 FA09 FA15 FA16 FA24                       GA01 GA12 GA32 GA61                 2H088 EA23 HA08 HA13 HA21 HA28                       MA02 MA04 MA06 MA16

Claims (5)

[Claims] 1. A display device comprising: a display device that emits display light; and a reflection member that reflects the display light, wherein the reflection member has a reflectance characteristic corresponding to a wavelength characteristic of the display light. A display device characterized by the above. 2. A display device comprising: a display device that emits display light; and a reflection member that reflects the display light, wherein the reflection member has a low reflectance in a wavelength range not emitted by the display device. A display device characterized by. 3. A display device having a first display portion which emits a first display light and a second display portion which emits a second display light,
A display device having a reflection member that reflects the first display light and the second display light, wherein the reflection member has a first wavelength range including at least the wavelength of the first display light. And a display device having a relatively high reflectance in a second wavelength range including the wavelength of the second display light. 4. A display having a first pixel that emits red light, a second pixel that emits green light, and a third pixel that emits blue light; and the red light, the green light, and the blue light. And a reflective member for reflecting, wherein the reflective member has a first wavelength range including the wavelength of the red light, a second wavelength range including the wavelength of the green light, and the blue color. A display device having high reflectance in a third wavelength range including the wavelength of light and relatively low reflectance in other wavelength ranges of visible light. 5. The display device according to claim 1, wherein the reflection member transmits infrared rays.