JPH07117525A - Head-up display - Google Patents

Abstract

PURPOSE:To provide a head-up display where the color easy to be recognized and the color difficult to be recognized by an observer such as a driver are not present, the information of the color difficult to be recognized is not made further difficult to be recognized by the information of the color easy to be recognized, and the display of a plurality of colors is possible. CONSTITUTION:A head-up display is provided where in a light-emitting and display means 14 to generate the information to be displayed as a plurality a color beams, a combiner 12 consisting of a hologram generates the beams of various colors with the intensity according to the respective diffraction efficiency of the beams of a plurality of colors to make an observer 11 recognize the driving information by the hologram 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a head-up display for vehicles, such as a head-up display (hereinafter referred to as HUD), which is capable of color display and is used for various displays.

[0002]

2. Description of the Related Art HUD has recently been used as a method of displaying information to a driver in a vehicle. In this system, optical information projected from display means such as a liquid crystal display device is displayed on a combiner composed of a half mirror or the like so that the driver can read the information from the driving state with almost no movement of the line of sight.

Recently, holograms have been attracting attention as the above combiner because of their simplicity as an optical element and the abundance of added functions. Since this holographic combiner can have not only the reflection function (diffraction function) but also the lens function etc.,
Optical information can be diffracted in the driver's visual field direction, or an image can be formed at an arbitrary position without using an optical system such as a lens. Another feature is that a large-screen display image can be obtained with high brightness without impairing the foreground brightness.

FIG. 8 is a conceptual diagram showing the structure of such a vehicle-mounted HUD. Here, 81 is a driver's observation position, 82 is a combiner by a hologram, 83 is light including information,
Reference numeral 84 is a lens system, 85 is a transmissive liquid crystal display element as a display, 86 is a light source including a halogen lamp, 87 is a windshield, and 88 is a display image (virtual image) formed in a distance.

Light emitted from a light source 86 passes through a lens system 84, which is a collimator, and a transmissive liquid crystal display element 85, and is applied to a hologram combiner 82 formed on a windshield 87 of a vehicle, diffracted and diffracted by a driver. It is visually recognized by the barrel viewer at the observation position 81. At this time, the display information is recognized by the driver as a virtual image at the position 88.

[0006]

When a hologram is used as a combiner, due to the wavelength selectivity of the hologram, external light transmitted through the hologram into the vehicle may be transmitted in a color tone unfavorable to the driver. Outside light reflected by the hologram outside the vehicle becomes light of a specific color and is visually recognized by a person outside the vehicle, a driver of an oncoming vehicle, or the like, and gives a glare feeling.

Therefore, by using a hologram that is exposed so as to diffract light of a plurality of colors, it is possible to make the light transmitted through the vehicle closer to white light and the light reflected outside the vehicle closer to white light. Proposed. In addition, considering the attachment angle of the windshield on which the hologram is placed and the incident angle of sunlight shining toward the windshield, the diffraction efficiency of diffracting light of each color in the hologram is adjusted to each color. According to the determination, the transmitted light and the reflected light can be made closer to white light.

Further, in the above case, by using the color CRT or the color liquid crystal as the light emitting display means, the information visually recognized by the driver can be displayed in color and a head-up display capable of transmitting a wide range of information is constructed. it can.

However, when a hologram whose diffraction efficiency is adjusted according to each color is used as a combiner as described above, the light of a certain color has a large luminance of the display virtual image, and the light of a certain color has a small luminance of the display virtual image. However, there is a drawback in that the display virtual image is poorly balanced depending on the respective colors, and good color display cannot be performed.

An object of the present invention is to solve the above-mentioned drawbacks of the prior art, and to provide a new head-up display capable of excellent display according to the displayed color. Especially.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and includes a light emitting display means for generating information to be displayed as light of a plurality of colors, and a display device which receives the plurality of lights. In a head-up display including at least a combiner that diffracts toward a viewer, the combiner is a hologram that is exposed to diffract light of a plurality of colors emitted from the light emitting display means, and the light emitting display means is , So that the light of each color is generated with an intensity according to the diffraction efficiency of each of the lights of multiple colors diffracted by the hologram so that the intensities of the lights of multiple colors viewed by the viewer are substantially uniform. And a head-up display.

[0012]

When the hologram is arranged on the windshield, the white light from the outside of the vehicle will pass through the complementary color of the light diffracted by the hologram, so that it will be visually perceived by the driver as light with an unfavorable safety. Will be. Similarly, the light reflected outside the vehicle does not have a desirable appearance for people outside the vehicle.

Therefore, for example, by using a hologram exposed by light of three colors of red, blue, and green, the transmitted light and the reflected light of the white light can be made white light. However, in this case, in order to obtain the above-mentioned white transmitted light and reflected light, the diffraction efficiency is adjusted according to each color, and the information visually recognized by the driver or the like is
The display varies depending on the color, resulting in an unbalanced information display.

In the head-up display of the present invention, the intensity of light of each color emitted by the light emitting display means is determined according to the diffraction efficiency of the hologram adjusted to make the transmitted light and the reflected light white. As the display information, the way of visually recognizing does not differ depending on the color, and in particular, when visually recognizing a plurality of colors at the same time, the information of the color that is difficult to visually recognize does not become more difficult to visually recognize due to the information of the easily recognizable color.

Specifically, for a hologram having different diffraction efficiencies depending on the light of a plurality of colors, the intensity of light emitted from the light emitting display means is increased for a color having a small diffraction efficiency, and conversely the diffraction efficiency is high. Regarding the color, by reducing the intensity of the light emitted from the light emitting display means, the intensity of the light of a plurality of colors visually recognized by the viewer can be made substantially uniform.

[0016]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a conceptual diagram showing the basic structure of the HUD in the present invention. 11 is a driver's observation position, 12 is a combiner made of a hologram, 13 is light including information, 14 is a light emitting display unit, 17 is a windshield, 18
Is a display image (virtual image) formed at a distance.

The light containing the information emitted from the light emitting display means 14 is diffracted by the combiner 12 formed of the hologram formed on the windshield 17 of the vehicle and is visually recognized at the observation position 11 by the viewer as a driver. At this time, the display information is visually recognized by the driver as a virtual image at position 18.

FIG. 2 is an example of a spectrum diagram showing the diffraction efficiency of the hologram in the present invention. In this example, a hologram was used as a combiner, which was subjected to multiple exposure so that the light after the white external light from the outside of the vehicle passed through the hologram and the light after the white external light was reflected by the hologram became white light. . Specifically, a hologram photosensitive material having a thickness of 20 μm is irradiated with light of three colors to be exposed,
Center wavelength 437 nm, half width 7 nm, diffraction efficiency 35% and center wavelength 543 nm, half width 9 nm, diffraction efficiency 55% and center wavelength 613 nm, half width 12 nm, diffraction efficiency 38%
I got a hologram. The diffraction efficiency of this hologram is shown in FIG.

The configuration of this hologram is not limited to the one obtained by multiple exposure on one sheet of the light-sensitive material as described above, but a plurality of holograms separately exposed by light of different colors may be laminated. It is preferable to perform multiple exposure on one sheet of light-sensitive material from the viewpoint that there is little image shift and decrease in the transmittance of the combiner.

FIG. 3 is a conceptual diagram showing an example of the light emitting display means in the present invention, 31 is a hot cathode tube as a light source and a jig for holding the hot cathode tube, 32 is a diffusion plate, and 33 is a transmissive display element. It is a TFT / LCD.

In this embodiment, four hot cathode tubes 31 having a high color rendering tube diameter of 8 mm and tube length of 119 mm are used. Further, in order to prevent unevenness in the illuminance of the light source, a diffusion plate 32 made by processing a white acrylic plate (Opal No. 422 manufactured by Mitsubishi Rayon) was installed between the hot cathode tube 31 and the TFT / LCD 33. The light source may be a hot cathode tube, a cold cathode tube, or a semiconductor laser, and a light source having a narrow half width is desirable in order to improve the quality of a displayed image, and a so-called bright line spectrum is preferable.

The TFT / LCD 33 has a screen size with a color filter of 4.6 cm in length, 6.2 cm in width and 240 in height.
This is a transmissive TN liquid crystal panel of a thin film transistor (TFT) active matrix drive system having pixels and 384 pixels in the horizontal direction.

As described above, the light emitted from the hot cathode ray tube is transmitted through the diffusion plate, and then transmitted through the TFT / LCD as the light emitted from the light emitting display means.
-The transmission spectrum which permeate | transmitted LCD is shown in FIGS. The transmission spectrum of the red part has a transmission spectrum as shown in FIG. 4, the transmission spectrum of the green part has a transmission spectrum as shown in FIG. 5, and the transmission spectrum of the blue part has a transmission spectrum as shown in FIG. .

When a light source having no bright line spectrum such as a halogen lamp is used, a color filter having a narrow half width can be used, but the light source energy is efficiently used, the heat generation countermeasure is complicated, and the total volume is reduced. Considering the size and the price of the color filter, the light source in this embodiment is preferable.

As shown in FIG. 2, the efficiency of light diffracted by the hologram varies depending on its color.
Under this condition, the main wavelength is 543 nm, that is, the green light is more visually recognized by the viewer than other colors such as red and blue. Therefore, by using the light emitting display means having the light intensity as shown in FIGS. 4, 5, and 6, the difference in the diffraction efficiency of the hologram depending on the color is alleviated.

FIG. 7 shows the chromaticity of red, green, and blue of the image displayed by the color holographic head-up display in the embodiment of the present invention.

In the present invention, the information to be displayed is appropriately selected according to its display application, and is particularly applicable to navigation map information which requires a high level of color display. , A tachometer, a warning display, etc. are given as examples.

The viewer is mainly the driver of the vehicle,
In addition, passengers such as the passenger seat and all passengers can be included.

The holograms in the examples of the present invention were acrylic photopolymers, and were Lippmann type volume / phase type holograms of 100 mm square. In addition to the above, various photosensitive materials such as polyvinylcarbazole-based photopolymers, dichromated gelatin, photoresists, and silver salts can be used as the hologram material, and as the hologram, volume / phase type such as Lippmann type can be used. However, the holograms such as emboss type holograms and rainbow type holograms can be widely used. The size of the hologram varies depending on the size of the display image to be obtained, the magnification, etc., but is usually an area of about several tens of mm to several hundreds of mm square, and the thickness is about several μm to several tens of μm. It is selected appropriately.

Such a hologram is usually arranged on the windshield, and may be provided on the surface of the windshield (the outer surface of the vehicle) or the inner surface of the vehicle, for example. It is preferably used by being enclosed inside a windshield which is glass.
Therefore, it is preferable that the hologram has a small thickness and excellent weather resistance, and the photopolymer used in the examples of the present invention is preferable.

The hologram in the present invention is not limited to the reflection hologram as described above, but a transmission hologram may be used.

As the light emitting display means, the light receiving type display element and the light source are used in combination even if the light source itself is patterned and arranged to generate specific information as light without using the light receiving type display element. In the case where the light receiving type display element is also used with a light source, an appropriate light collimating means such as a lens system or a curved reflecting mirror, a light guide plate or the like may be provided between the light receiving type display element and the light source. Appropriate light guide means may be provided. Furthermore, in the light path until the light is projected on the hologram,
If necessary, a light polarization means or a non-linear optical element such as KNO ₃ may be arranged.

[0034]

According to the present invention, for holograms having different diffraction efficiencies according to respective colors, the intensity of light of each color emitted from the light emitting display means is set according to the diffraction efficiency. Therefore, specifically, the intensity of light emitted from the light emitting display means is set so that the intensity of light of a color having a high diffraction efficiency is low and the intensity of light of a color having a low diffraction efficiency is high. Is set to.
Therefore, a driver or other viewer does not have a color that is easy to see and a color that is difficult to see, and when viewing multiple colors at the same time, the information of the color that is difficult to see is of a color that is easy to see. It is possible to obtain a head-up display capable of displaying a plurality of colors without making the information more difficult to visually recognize.

In particular, in the case of full color display by in-plane division of minute partial filters as seen in color display using a color CRT or liquid crystal, the intensity of light of each displayed color is substantially uniform. Therefore, it is possible to obtain a good color display in which each color is well balanced.

Further, the hologram of the present invention is exposed so as to diffract light of a plurality of colors, and the plurality of colors are diffracted by the light that is transmitted when the white light is irradiated onto the hologram. By selecting the light to be white light, it is possible to prevent the driver from visually perceiving light with a color tone that is unfavorable to safety when the hologram is placed on the windshield, and the light is reflected outside the vehicle. This is also the case for the light that illuminates, and it is possible to improve the appearance that is annoying to people outside the vehicle.

[Brief description of drawings]

FIG. 1 is a diagram conceptually showing the basic structure of a HUD in the present invention.

FIG. 2 is a spectrum diagram showing an example of diffraction efficiency of a hologram in the present invention.

FIG. 3 is a conceptual diagram showing an example of a light emitting display means in the present invention.

FIG. 4 is a spectrum diagram of light emitted from the light emitting display means in the embodiment of the present invention.

FIG. 5 is a spectrum diagram of light emitted from the light emitting display means in the embodiment of the present invention.

FIG. 6 is a spectrum diagram of light emitted from the light emitting display means in the embodiment of the present invention.

FIG. 7 is a chromaticity diagram of HUD in an example of the present invention.

FIG. 8 is a conceptual diagram showing a conventional HUD.

[Explanation of symbols]

 11, 81: Driver's observation position 12, 82: Hologram 13, 83: Information-containing light 14: Light emitting display means 17, 87: Windshield 18, 88: Display image (virtual image) 21: Diffraction of blue part of hologram Spectrum 22: Diffraction spectrum of green part of hologram 23: Diffraction spectrum of red part of hologram 31: Hot cathode tube 32: Diffusion plate 33: TFT / LCD 84: Lens system 85: Display 86: Light source

Claims (2)

[Claims] 1. A head-up display comprising at least a light-emitting display means for generating information to be displayed as light of a plurality of colors and a combiner for receiving the plurality of lights and diffracting the light toward a viewer. Is a hologram that is exposed so as to diffract light of a plurality of colors emitted from the light emitting display means, and the light emitting display means is configured to make the intensities of the light of a plurality of colors visually recognized by a viewer substantially uniform. ,
A head-up display, which generates light of each color with an intensity according to the diffraction efficiency of each of the lights of multiple colors diffracted by the hologram. 2. The head-up display according to claim 1, wherein the hologram is exposed with a plurality of colors of light so that the white light is diffracted by the white light.