JPH07251653A - Display device for vehicle - Google Patents

Abstract

PURPOSE:To provide a display device for a vehicle whereby necessary display brightness can be easily attained by using a fluorescent display tube. CONSTITUTION:Relating to a display device for a vehicle, display light from a virtual image light source 2 is turned back in a reflecting surface (meter cover 3) to obtain a distant virtual image display 5, and further an actual image display by a display pattern on the reflecting surface, irradiated by an actual image use light source 6 set up in the inside of the reflecting surface, is overlapped to make the display visible by providing a depth feeling. Accordingly, the display device for a vehicle is characterized by changing display color into white color, by arranging a hologram color filter 7 (reflecting or penetrating hologram), removing by diffraction a green region from a wavelength band of light emitted from a fluorescent character display tube which is the virtual image use light source 2, between the virtual image use light source 2 and the reflecting surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle display device for presenting various numerical values such as vehicle speed and engine speed and various warning lights to an occupant, and more particularly to a vehicle display device using a hologram element as a color filter. Regarding

[0002]

2. Description of the Related Art Recently, display light from a light source is reflected by a reflecting surface to display a distant virtual image, and is superimposed on a real image display by a display pattern on a reflecting surface illuminated by another light source installed inside the reflecting surface. 2. Description of the Related Art Display devices for vehicles have been developed that allow visual recognition with a sense of depth. An example of such a vehicle display device is shown in FIG. Figure 1
In FIG. 4, 1 is a meter visor, 2 is a fluorescent display tube that serves as a virtual image light source, 3 is a meter cover, 4 is the driver's eyes, 5 is a virtual image display, 6 is a real image light source, and 9 is an acrylic color filter. The virtual image light source 2 installed downward in the meter visor 1 is a fluorescent display tube, and has an emission color having a peak of green due to the fluorescent composition of ZnO: Zn. The display light emitted from the virtual image light source 2 is reflected by the surface of the meter cover 3 and reaches the eyes 4 of the driver to display a virtual image display 5 in the distance.
Becomes The virtual image display 5 is recognized with a depth, overlapping the real image display of the display pattern on the meter cover 3 illuminated by the real image light source 6. However, since the fluorescent display tube has an emission color having a peak of green, it is necessary to change this to white. The acrylic filter 9, which also serves as a cover for the virtual image light source 2, is a filter for changing the color tone from green to white, and is a grape-based filter that has a high transmittance of blue and red and suppresses the transmission of green. Change the green display light to a white tone.

The reason why the color tone of the green generated by the fluorescent display tube is changed to white and the meter display is changed to white as described above is as follows. Improvement of visibility By making the display image white against the black meter panel background, a higher contrast can be obtained compared to the green display, and the driver's display visibility is improved. Improvement of display quality By changing the color from green to white, the stimulus value of the color is reduced, and the display is soft to the eyes of the driver, so that the feeling of luxury is increased and the display quality is improved.

[0004]

As described above, in the conventional vehicular display device, the green light emitting fluorescent display tube is used, and the color tone is changed from green to white by the acrylic filter 9. There is. However, since the acrylic filter 9 has a gradual change in spectral transmission characteristics, it also blocks transmission of blue and red, which is not necessary for color tone change in order to remove a necessary green region. Therefore, as a result, a large reduction in brightness is caused. This was an unavoidable phenomenon as long as it has the current composition. The fluorescent display tube has characteristics such as small size, thinness, low power consumption, and small heat generation amount suitable for a vehicle display device. However, for the above reasons, a light source is required to achieve the required display brightness. Therefore, it is required to increase the brightness of the fluorescent display tube side. Therefore, there is a problem that the cost is increased because a cooling means such as a heat sink is required, and there is also a problem that the life of the fluorescent display tube is shortened due to the ultra-high brightness. It should be noted that if a white light source such as a halogen lamp or an incandescent lamp is used, there is no problem in terms of color tone and brightness, but due to its large size, large power consumption, and large calorific value, it is difficult to use for the vehicle display device as described above. is there.

The present invention has been made in order to solve the problems of the prior art as described above, and provides a fluorescent display tube having characteristics suitable as a light source for a vehicle display device in terms of color tone and brightness. An object of the present invention is to provide a vehicular display device that can easily achieve a required display brightness by using the display device.

[0006]

In order to achieve the above object, the present invention is constructed as described in the claims. That is, in the invention according to claim 1, the display light from the virtual image light source is reflected by the reflecting surface to form a distant virtual image display, and the display on the reflecting surface illuminated by another light source installed inside the reflecting surface. In a vehicular display device that is visually recognized with a sense of depth by overlapping with a real image display by a pattern, a green range is provided between a virtual image light source and a reflecting surface from a wavelength band of light emitted by a fluorescent display tube that is a virtual image light source. A reflective hologram to be removed by diffraction is arranged and the display color is changed to white. The above configuration corresponds to, for example, the embodiment shown in FIG. 1 described later.

Further, in the invention described in claim 2,
A transmissive hologram is placed between the virtual image light source and the reflecting surface to separate the green region from the wavelength band of the light emitted by the fluorescent display tube, which is the virtual image light source, in the other direction and remove it from the optical path of the display light. It is configured to change the color to white. The above configuration corresponds to, for example, the embodiment shown in FIG. 11 described later. Further, in the invention according to claim 3, as the virtual image light source, a multi-color light emitting light source including at least one color of red, blue, and orange and green is used to display a virtual image of a plurality of colors. It is configured in. As the multi-color light source, one light source may emit a plurality of colors, or a plurality of light sources that emit different colors may be provided. In addition, the above-described configuration has, for example, FIG.
Corresponding to the embodiment.

Further, in the invention described in claim 4,
As a virtual image light source, a liquid crystal display element and an incandescent lamp that serves as its back lighting are used, and reflection between the virtual image light source and the reflection surface is performed by diffraction to remove the yellow-red region from the wavelength band of light emitted by the virtual image light source. A type hologram is arranged so as to suppress a change in chromaticity in the reddish direction when the light is dimmed. In the invention according to claim 5,
As a virtual image light source, a liquid crystal display element and an incandescent light bulb that serves as its back illumination are used, and between the virtual image light source and the reflecting surface, the yellow-red region is diffracted in another direction from the wavelength band of the light emitted by the virtual image light source. A transmissive hologram that is removed from the optical path of the display light is arranged so as to suppress the change in chromaticity in the reddish direction when the light is dimmed. The configurations described in claims 4 and 5 correspond to, for example, a fourth embodiment described below. The incandescent lamp includes a halogen lamp and an incandescent lamp.

[0009]

As described above, in the present invention, a hologram having a high wavelength selectivity is used so that only a specific wavelength band necessary for changing the color tone of the green light emitted from the fluorescent display tube to white is removed by diffraction. It is composed. By using the hologram as a color filter in this way,
High-quality white display is possible with a minimum reduction in display brightness. Therefore, since high brightness is not required on the light source side, heat measures such as a heat sink are not required, and the life is not shortened, so that the cost can be reduced. Further, the color filter using the hologram in the present invention,
When the optical characteristics are matched with the whitening of green, the spectral characteristics of other colors are hardly affected. Therefore, with respect to red, blue, orange, and the like, there is almost no decrease in luminance or change in color due to transmission. Therefore, a virtual image display of a plurality of colors can be performed by installing a virtual image light source for emitting a plurality of colors including a light source of a color other than green in the hologram color filter. Further, as described in claims 4 and 5, when a liquid crystal display element and an incandescent light bulb which is the back lighting thereof are used as the virtual image light source, arbitrary display by dot matrix formation becomes possible. At the same time, there is an advantage that it can be constructed at low cost as long as the problems of large size and large heat generation can be solved. However, when an incandescent light bulb is simply used as a virtual image light source, when the light is dimmed according to the surrounding environment (such as at night), the color tone shifts to the yellow-red region as the brightness is lowered, and the display color changes. There is a problem that it ends up. Therefore, in claims 4 and 5, a chromaticity change in the reddish direction at the time of dimming is achieved by excluding the yellow-red region from the wavelength band of the light emitted by the virtual image light source using a reflection hologram or a transmission hologram. Is suppressed.

[0010]

EXAMPLES The present invention will be described below based on examples.
FIG. 1 is a sectional view showing a first embodiment of the present invention. In FIG. 1, 1 is a meter visor, 2 is a virtual image light source, 3 is a meter cover, 4 is a driver's eyes, 5 is a virtual image display, 6 is a real image light source, 7 is a hologram color filter composed of a reflection hologram, 8 Is diffracted light diffracted by the hologram color filter 7. For convenience of illustration, the virtual image display 5 and the real image and the eyes 4 of the driver are refracted and displayed.
In reality, they are connected in a straight line. The hologram color filter 7, which is a main constituent element of the present invention, is composed of a reflection hologram attached to a transparent member that covers the virtual image light source 2. The display light emitted from the virtual image light source 2 enters the reflection hologram of the hologram color filter 7 at an incident angle θin, and rotates according to the optical characteristics (diffraction center wavelength λc, diffraction efficiency η, half-value width Δλ) of the reflection hologram. Break angle θ
It is diffracted at out and becomes diffracted light 8. The diffracted light 8 is emitted in a direction opposite to that of the meter cover 3 as shown in the figure and is excluded from the display light. The display light from which the diffracted light 8 has been removed as described above is reflected by the surface of the meter cover 3 and is recognized by the driver as the virtual image display 5. Although the incident angle θin and the diffraction angle θout are shown equal in FIG. 1, θin ≠ θout may be satisfied unless the diffracted light 8 is incident on the eyes 4 of the driver even after being reflected several times. .

Next, the operation will be described. The display light of the virtual image display 5 that is incident on the eyes 4 of the driver is the light that has passed through the reflection type hologram among the spectral distribution characteristics of the virtual image light source 2,
This is the light from which the diffracted light 8 has been removed. In this case, if only the green region necessary for whitening the virtual image light source 2 which is originally green can be removed by diffraction, it is considered possible to change the color tone while minimizing the decrease in brightness. This can be done by using highly selective hologram diffraction. Here, as the color display method, "XYZ color system" and "X ₁₀ Y ₁₀ Z ₁₀ color system" shown in "JIS Z 8701" are used.
The field of view from the observer is applied so that the correlation can be obtained for the fields of view of 1 to 4 ° and those exceeding 4 °, respectively. In this case, from the display image size of the vehicle display device, "XYZ
"Color system" is used. The "chromaticity coordinates x, y, z" can be obtained from the above "XYZ color system" and the color can be displayed as the chromaticity coordinate value on the chromaticity diagram shown in FIG. In FIG. 2, a curve with a wavelength scale is a spectrum locus, and a straight line connecting both ends of the spectrum locus is a pure purple locus. Also, points A, B, C and D ₆₅ represent the chromaticity coordinates of standard lights A, B, C and D ₆₅ . Virtual light source 2
Let S (λ) be the spectral distribution characteristic of η, the diffraction efficiency for each wavelength of the reflection hologram be η (λ), and neglect the attenuation during light transmission, the approximate value of the chromaticity of each light can be calculated. I can. First, from the spectral distribution S (λ) of the light source, the tristimulus values XYZ of the light source color are represented by the following (Equation 1).

[0012]

[Equation 1]

In the equation (1), the numeral 780 at the upper end and the numeral 380 at the lower end of the integral symbol indicate the wavelength (nm) of light, respectively. Further, the light source color after passing through the hologram is the original light source color multiplied by the spectral transmittance τ (λ) of the hologram, and τ (λ) = 1-η (λ). From the equation, it becomes as shown in the following (Equation 2).

[0014]

[Equation 2]

The chromaticity coordinates x, y, z are as shown in the following (Equation 3) from each tristimulus value XYZ.

[0016]

[Equation 3]

Further, what color the chromaticity coordinate value obtained by calculation will be, in "JIS Z 8110, light source color-color name", is a general chromaticity classification of systematic color names shown in FIG. Can be classified by. In FIG. 3, the abscissa x
The ordinate y indicates the "JIS Z 8701" (XYZ color system and X ₁₀ Y ₁₀ Z ₁₀ color display method according to color system) XYZ colorimetric system chromaticity coordinates by. FIG. 4 is a characteristic diagram showing the spectral distribution characteristic S (λ) of a typical green fluorescent display tube. When the chromaticity calculation is performed from FIG. 4, the chromaticity coordinate value x =
It becomes 0.24, y = 0.43, and if this is applied to the chromaticity classification of FIG. 3, it is classified as "green". The diffraction efficiency of the hologram required to change this into the display colors of "white" and "purple, bluish, greenish, and yellowish white" is as follows. First, in FIG. 5, the diffraction center wavelength λ is obtained by combining the actual diffraction efficiency η of the hologram and the half width Δλ.
It is the figure which plotted the chromaticity coordinate change at the time of changing c on a chromaticity diagram. Further, in FIG. 6, the chromaticity coordinate values are “white” and “purple, bluish, greenish, and yellowish white”.
4 is a chart showing a diffraction center wavelength region that becomes This is the desired hologram characteristic. In the above case, the transmittance with respect to the light source is about 59% at the minimum and about 74% at the maximum, and the transmittance with the conventional grape-color acrylic filter is about 2%.
It is possible to obtain a display brightness which is 2-3 times as high as that of 4%.
7 and 8 are spectral transmission characteristic diagrams. FIG. 7 shows the characteristic of the hologram color filter used for the above calculation, and FIG. 8 shows the spectral transmission characteristic of the acrylic color filter. As can be seen from FIGS. 7 and 8, the transmittance of the acrylic color filter is reduced in a wide range, whereas the transmittance of the hologram color filter is reduced only in the green region of 480 to 550 nm, and the other portions. Shows good transmission characteristics.

Next, a method of manufacturing a reflection hologram having the above characteristics will be described. FIG. 9 is a cross-sectional view showing a method of manufacturing a reflection hologram. In FIG. 9, 1
Reference numeral 0 is a hologram photosensitive material (more precisely, a volume hologram photosensitive material), 11 is a plane mirror, 12 is a laser oscillator, 13 is a spatial filter, and 14 is a collimating lens. The laser light emitted from the laser oscillator 12 becomes divergent light by the spatial filter 13, and is collimated by the collimator lens 14,
It enters the hologram photosensitive material 10 as signal light 15.
The signal light 15 reflected by the plane mirror 11 becomes the reference light 16,
The interference fringes 17 are formed inside the hologram photosensitive material 10 due to the interference between the signal light 15 and the reference light 16. Hereinafter, a method for realizing desired exposure / reproduction conditions will be described.

FIG. 10 is a diagram showing hologram exposure / reproduction conditions. In FIG. 10, λo is the oscillation wavelength of the exposure laser, λc is the diffraction center wavelength of the desired hologram under the reproduction angle condition, θr is the angle condition of the reference light in the hologram photosensitive material, and θo is the signal light of the hologram photosensitive material. , Θc is the angle condition of the display light in the hologram photosensitive material, and θi is the angle condition of the diffracted light in the hologram photosensitive material. Here, if the average refractive index of the hologram at the time of exposure is no and the average refractive index of the hologram at the time of reproduction is nc, the following equation (4) is established.

[0020]

[Equation 4]

In the case of the reflection hologram used in this embodiment, no = 1.5 nm, nc = 1.51 nm, λo = 514.5 nm using the laser oscillator 12 as an Ar ion laser, and the desired λc = required for whitening. When it is set to 521 nm,
If incident angle θin = diffraction angle θout = 10 ° in FIG. 1, θc and θi are calculated as θc = 6.6 ° and θi = 173.4 °, respectively, from the refractive index difference between the air and the hologram photosensitive material. To be Therefore, from equation (4), θr = 9.1 ° and θo = 1
70.9 ° is required. By using the apparatus of FIG. 9 so as to satisfy the above conditions, it is possible to realize a reflection hologram that changes the color tone from green to white as described above.

Next, FIG. 11 is a sectional view of the second embodiment of the present invention. In this embodiment, the hologram color filter 7'is composed of a transmission hologram, and the other structures are the same as those in FIG. In this embodiment, the diffracted light in the partial wavelength range (green range) passes through the hologram and travels toward the meter cover 3. However, since the optical path is different from that of the display light, after being reflected by the meter cover 3, The driver's eyes 4 are never reached. Therefore, it is perceived by the driver as white light excluding the green range. Comparing such a transmissive hologram with the above-mentioned reflective hologram has the following characteristics. That is, when the change in the diffraction wavelength with respect to the change in the incident angle is calculated with the average refractive index of the hologram being 1.51, the diffraction center wavelength is 550 nm.
In the case of the reflective type, the incident angle: the diffraction angle is 15 °: 15 ° to 2 °
It changes to 2.5 °: 22.5 °, and in the transmission type, the incident angle: diffraction angle changes from 15 °: -165 ° to 14.7 °: -165.3 °. As mentioned above, in the reflection type, both the incident angle and the reflection angle are 7.
In contrast to the change of 5 °, in the transmission type, both the incident angle and the reflection angle change only 0.3 °, which shows that the change in the transmission type angle is significantly small. This indicates that the change in the color tone of the display color is extremely small with respect to the change in the driver's posture. Therefore, since the display color does not change even when the driver changes his / her posture, the display quality can be improved.

Next, a method of manufacturing a transmission hologram having the above characteristics will be described. FIG. 12 is a cross-sectional view showing a method of manufacturing a transmission hologram. In FIG. 12, 10 is a hologram photosensitive material (more precisely, a volume hologram photosensitive material), 12 is a laser oscillator, 13 is a spatial filter, 14 is a collimating lens, 18 is a half mirror,
19 is a mirror. The laser light emitted from the laser oscillator is branched by the half mirror 18, part of which becomes divergent light by the spatial filter 13 and becomes parallel light by the collimator lens 14 and becomes signal light 15. Further, the other part branched by the half mirror 18 becomes divergent light by the spatial filter 13 ',
The collimator lens 14 ′ collimates the light into the reference light 16. The signal light 15 and the reference light 16 are incident on the hologram photosensitive material 10 from the same surface side. Due to the interference between the signal light 15 and the reference light 16, an interference fringe 17 is formed inside the hologram photosensitive material 10. As for the method for realizing the desired exposure / reproduction conditions, no. = 1.0 by using FIG. 10 and the equation (4) as in the first embodiment.
5 nm, nc = 1.51 nm, the laser oscillator 12 is an Ar ion laser having λo = 514.5 nm, and the desired λc = 521 nm required for whitening is set, the incident angle θin = diffraction angle θout = 10 ° of FIG. Then, θc = 6.6
°, θi = -6.6 °, θr = 6.56 °, θo = -6.56
° is required. As shown in FIG.
By using the apparatus described above, it is possible to realize a transmission hologram that changes the color tone from green to white as described above.

Next, the effect range of the hologram color filter for colors other than green will be described. Representative colors other than green used for vehicle meter displays include red, blue, and orange. For example, a red display representing the red zone in the engine speed display can be made to emit light in the vicinity of the main display green by changing the fluorescent body in the same fluorescent display tube. In the color filter using the hologram according to the present invention, when the optical characteristics of the color filter are matched with whitening of green, the spectral characteristics of other colors are hardly affected. Therefore red, blue,
With respect to orange and the like, there is almost no decrease in brightness or change in color due to transmission. Therefore, by installing a light source that emits a color other than green in the hologram color filter, it is possible to display a virtual image of another color together with the white display. The light source may be one that emits a plurality of colors, or a plurality of light sources that emit different colors may be provided.

FIG. 13 is a diagram showing a third embodiment of the present invention, and shows a case where the multicolor display as described above is applied to a meter for a vehicle. In FIG. 13, white display (vehicle speed display and rotation speed display portion), red display (revolution speed display red zone), and red, blue, green, and orange mixed display (various warning lights and blinkers) Etc.). All of the above displays may be real image displays,
The vehicle speeds, rotational speeds, and red zones of and may be displayed in a virtual image, and may be displayed in various combinations so as to be displayed in a real image. However, regarding the green display,
It is necessary not to pass the hologram color filter.

Next, a fourth embodiment of the present invention will be described.

In the first to third embodiments, a fluorescent display tube is used as the virtual image light source. However, when a liquid crystal display element and an incandescent light bulb that serves as its back lighting are used as the light source for the virtual image, arbitrary display by dot matrix formation is possible, and even the problems of large size and large heat generation are solved. If possible, there is an advantage that the configuration can be inexpensive. However, when an incandescent light bulb is simply used as a virtual image light source, when the display device is dimmed according to the surrounding environment (nighttime, etc.), the color tone shifts to the yellow-red region as the brightness is lowered, and the display color changes. There is a problem that it will change. That is, the incandescent light bulb heats the filament and emits light by its thermal radiation. When the filament temperature T is changed by adjusting the brightness, the spectral distribution also changes. In addition,
The locus of chromaticity points from T = 0 to ∞ is called a perfect radiator locus. For example, when T = 3200K with an incandescent light bulb, the chromaticity is x = 0.423, y = 0.399, and it is located almost on the white area, but when the brightness is about 1/10, T = 2475K, The chromaticity changes to a yellow-red region with x = 0.479 and y = 0.414. Therefore, when the display device is dimmed according to the brightness of the surroundings at night or the like, the color tone will change. Therefore, in this embodiment,
By placing a reflection hologram or a transmission hologram between the virtual image light source consisting of the liquid crystal display element and the incandescent light bulb and the reflecting surface, and removing the yellow-red region from the wavelength band of the light emitted from the virtual image light source of the incandescent light bulb, It suppresses the change in chromaticity in the reddish direction when light is applied. As a specific configuration, in FIG. 1 or FIG. 11, as the virtual image light source 2, a light source in which an incandescent lamp is installed on the back surface of the liquid crystal display element may be used. The optical characteristics of the hologram color filter 7 or 7'in this case are, for example, T =
When changing from 3200K to about 1/10 T = 2475K, λc = 595 nm, η = 95%, Δλ
= 50 nm, chromaticity x = 0.407, y
It can stay in the white area of 0.418.

[0028]

As described above, according to the present invention, the color filter is composed of a hologram having a high wavelength selectivity, and the specific wavelength band necessary for changing the color tone of the green light emitted from the fluorescent display tube to white. By only removing only the light by diffraction, high quality white display can be achieved with a minimum decrease in display brightness. Therefore, since high brightness is not required on the light source side, heat measures such as a heat sink are not required, and the life is not shortened, so that the cost can be reduced. Further, when the hologram color filter is composed of a transmission hologram, the change of the diffraction center wavelength with respect to the change of the incident angle is significantly smaller than that of the reflection hologram, and therefore the influence of the posture movement of the driver on the change of the color tone is Since the display color is reduced even when the driver changes his posture, the display quality can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view of a first embodiment of the present invention.

FIG. 2 is a chromaticity diagram.

FIG. 3 is a general chromaticity classification diagram of systematic color names.

FIG. 4 Spectral distribution characteristic S of a typical green fluorescent display tube
The characteristic view which shows ((lambda)).

FIG. 5 is a diagram in which a change in chromaticity coordinates is plotted on a chromaticity diagram when the diffraction center wavelength λc is changed by a combination of the actual diffraction efficiency η of the hologram and the half width Δλ.

FIG. 6 shows chromaticity coordinate values of “white” and “purple, bluish,
FIG. 6 is a chart showing the diffraction center wavelength range of “greenish and yellowish white”.

FIG. 7 is a characteristic diagram showing the spectral transmittance of a hologram color filter.

FIG. 8 is a characteristic diagram showing the spectral transmittance of an acrylic color filter.

FIG. 9 is a cross-sectional view showing a method of manufacturing a reflection hologram.

FIG. 10 is a diagram showing exposure / reproduction conditions for a hologram.

FIG. 11 is a cross-sectional view of the second embodiment of the present invention.

FIG. 12 is a sectional view showing a method of manufacturing a transmission hologram.

FIG. 13 is an embodiment diagram showing a multicolor display example of a vehicle meter.

FIG. 14 is a cross-sectional view of an example of a conventional device.

[Explanation of Codes] 1 ... Meter visor 4 ... Driver's eyes 2 ... Virtual image light source 5 ... Virtual image display 3 ... Meter cover 6 ... Real image light source 7 ... Hologram color filter composed of reflection hologram 7 '... Transmission hologram Constructed hologram color filter 8 ... Diffracted light diffracted by the hologram color filter 10 ... Hologram photosensitive material 15 ... Signal light 11 ... Plane mirror 16 ... Reference light 12 ... Laser oscillator 17 ... Interference fringes 13 ... Spatial filter 18 ... Half mirror 14 ... Collimating lens 19 ... Mirror

Claims (5)

[Claims] 1. A display light from a virtual image light source is reflected by a reflecting surface to form a distant virtual image, and is superimposed on a real image display by a display pattern on a reflecting surface illuminated by another light source installed inside the reflecting surface. In a display device for a vehicle that is visually recognized with a sense of depth, a reflection type that removes a green region from a wavelength band of light emitted by a fluorescent display tube that is a virtual image light source by diffraction between the virtual image light source and the reflection surface. A display device for a vehicle, wherein a hologram is arranged and a display color is changed to white. 2. Display light from a virtual image light source is reflected by a reflecting surface to form a distant virtual image, and is superimposed on a real image display by a display pattern on the reflecting surface illuminated by another light source installed inside the reflecting surface. In a display device for a vehicle to be viewed with a sense of depth, between the virtual image light source and the reflecting surface, a green region is diffracted in another direction from a wavelength band of light emitted by a fluorescent display tube that is a virtual image light source. A display device for a vehicle, characterized in that a transmission hologram is arranged to be removed from the optical path of the display light by changing the display color to white. 3. The vehicle display device according to claim 1, wherein the virtual image light source is a multicolor light emitting light source including at least one of red, blue, and orange and green. A vehicle display device characterized by displaying virtual images of a plurality of colors. 4. The vehicle display device according to claim 1 or 2, wherein a liquid crystal display element and an incandescent light bulb that serves as a back illumination thereof are used as the virtual image light source, and the virtual image light source and the reflection are used. A vehicle display device characterized in that a reflection hologram for removing the yellow-red region from the wavelength band of the light emitted from the virtual image light source by diffraction is arranged between the surface and the surface to suppress the chromaticity change in the reddish direction at the time of dimming. . 5. The vehicle display device according to claim 1 or 2, wherein a liquid crystal display element and an incandescent light bulb that serves as a back lighting thereof are used as the virtual image light source, and the virtual image light source and the reflection are used. A transmissive hologram that diffracts the yellow-red region from the wavelength band of the light emitted by the virtual image light source in a different direction and removes it from the optical path of the display light is placed between the surface and the surface to suppress chromaticity change in the reddish direction during dimming. A vehicle display device characterized by the above.