JP3427559B2 - Display device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device having a semi-transparent display screen such as a head-up display of an automobile for visually recognizing a display image on a background.

[0002]

2. Description of the Related Art In ordinary driving of a vehicle, in order to confirm a speed display or the like, it is necessary to temporarily shift the line of sight from an outside scene to instruments on an instrument panel. Although this operation is indispensable for driving, it is a very troublesome operation. It is also said that frequent movements of the line of sight cause considerable fatigue to the driver. Therefore,
In recent years, there has been proposed a head-up display that has been conventionally used in a fighter aircraft or the like, which is capable of simultaneously checking information necessary for driving such as speed and the external scene by using a holographic optical element at the same time.

In this head-up display,
A holographic image combiner using a reflection hologram is used as a combiner for superposing a plurality of pieces of information. The holographic combiner is provided with a diffraction characteristic that efficiently reflects only light in a specific selected wavelength band. As a result, the hologram combiner reflects the light emitted from the display (information light source) with high efficiency, while having a high transmittance for the light other than the above specific wavelength range, the light coming from the background is Most can be transmitted.

As a result, the brightness of the scene viewed through the hologram combiner and the display of the speed reflected by the hologram combiner are not impaired. However, the light transmitted through the combiner does not include the light in the selected wavelength band, so that the background seen through the combiner appears to be tinted to the complementary color of the light in the selected wavelength band. In order to solve this problem, JP-A-4-291221 and JP-A-3-17941
Japanese Patent Laid-Open No. 8 and Japanese Patent Laid-Open No. 3-103816 are proposed.

That is, Japanese Patent Application Laid-Open No. 4-291221 proposes that, in the hologram combiner, an optical member whose transmittance depends on the wavelength is superposed on the hologram combiner to remove the tint of the background light. ing. In addition, in Japanese Patent Laid-Open No. 3-179418, it is proposed to dispose an optical element that reflects or attenuates light having a wavelength that is a complementary color of the selected wavelength band, in addition to the hologram. Further, in Japanese Patent Laid-Open No. 3-103816,
A method using a hologram having two or more types of selected wavelength bands having a complementary color relationship has been proposed.

Further, as another problem, there are the following problems. This is because outside light such as sunlight is diffracted and reflected as visible light by the hologram from a person or a pedestrian in another vehicle (an oncoming vehicle, etc.), and in particular, it is specified in the selected wavelength band. When the colored light is diffracted, it is recognized as a glaring and unpleasant color. This is not preferable in terms of safety in oncoming vehicles. In order to solve this, it is proposed in Japanese Patent Laid-Open No. 4-110984 to superimpose a second hologram that reflects a second wavelength that weakens the stimulus on the first hologram. Further, Japanese Patent Application Laid-Open No. 5-124456 proposes a method in which a plurality of selected wavelength bands of the hologram are provided and a neutral color is obtained when the lights of the plurality of selected wavelength bands are mixed. .

[0007]

[Problems to be Solved] As described above, since the light transmitted through the hologram combiner of the head-up display does not include the light in the selected wavelength band, the background visible through the combiner is colored with a complementary color of the light in the selected wavelength band. There is a first problem that is caused. On the other hand, the measures taken by the three publications (Japanese Patent Laid-Open No. 4-291221, etc.) for solving this problem are to reduce the intensity of the background light to remove the tint, and the brightness of the background is impaired. However, it is not a complete countermeasure.

Further, as described above, for a person or a pedestrian in an oncoming vehicle or the like, external light such as sunlight is diffracted and reflected as visible light by the hologram, and information is displayed. The second problem is that a particular color that is conspicuous such as in the selected wavelength band is reflected, and a glistening and unpleasant color with strong stimulation is visually recognized, which is not preferable from a safety point of view.

In order to solve this second problem, Japanese Laid-Open Patent Publication No. 4-110984 proposes superimposing holograms reflecting a second wavelength that weakens the stimulus. Japanese Patent Laid-Open No. 5-124456 proposes to provide a plurality of selected wavelength bands for forming a neutral color.

However, according to this countermeasure, although there is an effect of suppressing unpleasant reflected light when viewed from an angle within a certain range, the angle selectivity of the light of the hologram makes it possible to obtain an intermediate light at other angles. There is a problem that the color does not become a sexual color and the color becomes more conspicuous because there are a plurality of selected wavelength bands. The present invention has been made in view of such conventional problems, and an improved display device or a viewer capable of suppressing the stimulating reflection of external light of a hologram to an external person in a wide angle range. It is an object of the present invention to provide an improved display device that can provide a display that is even easier to see.

[0011]

According to a first aspect of the present invention, a back side scene of a screen is visually recognized by light transmitted from the back side of the screen, and a display image is visually recognized on the background by light reflected from the front side of the screen. A configured display device, wherein the display device includes an information light source that emits the display image, and a light-transmissive reflective hologram optical element that diffracts the light emitted from the information light source, The hologram optical element has at least four or more selected wavelength bands, and the selected wavelength bands have a chromaticity relationship of forming approximately an intermediate color at an incident angle at which a viewer visually recognizes information light.
Characterized by comprising at least one visible light band and at least one of a short-wavelength band between the ultraviolet light band and a visible light band near the ultraviolet band or a long-wavelength band in the near-infrared band. On the display.

What is most noticeable in the first invention is that
The hologram optical element has four or more selected wavelength bands,
This selected wavelength band consists of a visible light band having a chromaticity relationship that forms an intermediate color due to color mixing and a visually impaired band. This visually impaired band is a short wavelength band between the visible light band and the visible light band near the ultraviolet region. Alternatively, at least one of the long wavelength bands in the near infrared region is included.

The visible light band having a chromaticity relationship for forming an intermediate color is selected, for example, from 400 to 500 nm (red), 50
It can be easily obtained by combining the three primary colors in the range of 0 to 570 nm (green) and 570 to 760 nm (blue). In addition, the blind zone is a short wavelength band,
0 nm to 400 nm, more preferably 360 nm to
It is preferably within the range of 380 nm. The reason is as described below.

As will be described later in detail in embodiments, in a head-up display, generally, the position of the outside human eyes is about several tens clockwise from the position where the ground angle θ of the line of sight with respect to the hologram is about 0 °. It is distributed in the positions that are gradually increased. On the other hand, in a general head-up display, when the selected wavelength band and the mounting angle of the hologram are set so that the tint is removed from the background, the angle of the line of sight θ of the line of sight is set by the selectivity of the angle of the hologram. As the wavelength increases from 0 ° in the clockwise direction, the wavelength of the selected wavelength band normally changes to become longer (see Tables 1 and 2).
As a result, the light in the above-mentioned difficult-to-see band becomes tinged with color and can be visually recognized, and it acts to catch the change in tinge in other visible light selection wavelength bands, and the line-of-sight angle θ of the outside person changes. This is also because it suppresses the hologram reflected light from being a stimulating reflected light from a neutral color.

The hologram optical element having a plurality of selected wavelength bands as described above is manufactured by, for example, stacking a plurality of hologram elements and using a photosensitive material having a high sensitivity over a wide area. It can be realized by one hologram element. The above-mentioned photosensitive materials exhibiting high sensitivity over a wide range include dichromated gelatin and photopolymers.

On the other hand, the second invention of the present application is configured such that the scene on the back side is visually recognized by the light transmitted from the back side of the screen, and the display image is visually recognized on the background by the light reflected from the front side of the screen. In the above display device, the display device includes an information light source that emits the display image, and a light-transmissive reflective hologram optical element that diffracts the light emitted from the information light source. The hologram optical element includes a hologram and a light emitting means, and the hologram has the following characteristics at an incident angle at which a viewer visually recognizes the information light.
The light emitting means has three or more selected wavelength bands in the visible light region having a chromaticity relationship that forms an approximately neutral color, and the light emitting means emits light near the shortest wavelength band or near the longest wavelength band in the selected wavelength band. A display device characterized by emitting light.

What is most noticeable in the second invention is that
The hologram has three or more selected wavelength bands in the visible light region having a chromaticity relationship that mixes colors to form an intermediate color, and the light emitting means has light in the vicinity of the shortest wavelength band in the selected wavelength band or in the vicinity of the longest wavelength band. Is to emit light. The selected wavelength bands having a chromaticity relationship for forming an intermediate color are, for example, 400 to 500 nm, 500 to 570 nm, 570 to 7
It can be obtained by combining primary colors in the range of 60 nm.

In the above, it is preferable that the light emitting means emits light in the vicinity of the shortest wavelength band in the selected wavelength band of the hologram. As will be described later in detail in the embodiments, in the head-up display, the ground angle θ of the line of sight of the person outside the vehicle with respect to the hologram is generally 0.
Often in the vicinity of °, the probability that the line of sight exists decreases as the value of θ increases in the clockwise direction. According to the usual arrangement of the head-up display, as the ground angle θ of the line of sight increases clockwise as described above, the wavelength of the selected wavelength band of the hologram changes in the direction of increasing. Therefore, by making the emission wavelength band of the light emitting means, which has a constant wavelength and does not change, toward the short wavelength band side, the effect of alleviating the change of the selected wavelength band in the red (long wavelength) direction can be exerted. Because you can

According to a third aspect of the present invention, a display configured to visually recognize a scene on the back side by the light transmitted from the back side of the screen and visually recognize a display image on the background by the light reflected from the front side of the screen. The display device includes an information light source that emits the display image and a light-transmissive reflective hologram optical element that diffracts the light emitted from the information light source. The element is
The display device is provided with a hologram and a light emitting means, and the light emitting means emits light within a selected wavelength band of the hologram. What is most noticeable in the third invention is that the hologram element includes a hologram and a light emitting means, and the light emitting means emits light within the selected wavelength band.

The light emitting means in the second and third inventions includes, for example, an active element such as electroluminescence (EL) driven by electric energy or the like, and a passive element containing a luminescent dye such as a fluorescent dye. There is a typical light emitting element. The holograms in the second and third inventions include, for example, a multilayer hologram device formed by stacking a plurality of hologram elements, and a single hologram element manufactured using a photosensitive material having high sensitivity over a wide area. There is. The display device according to the first to third inventions is
It is suitable for use as a head-up display (see Examples for details).

[0021]

In the display device according to the first aspect of the present invention, the selected wavelength band in the visible light region of the hologram optical element has a chromaticity relationship that forms an intermediate color. Therefore, the complementary color light in the selected wavelength band which reaches the viewer through the hologram becomes colorless, and the viewer can visually recognize the scene on the back side of the screen as a natural scene without tint (the first problem described above). Resolution of points).

On the other hand, with respect to an external person on the back side of the display device, the light reflected by the hologram optical element has a predetermined incident angle such that the incident angle of the white external light is the same as the incident angle of the information light on the hologram. If it is α, the reflected light also becomes an intermediate color, and the hologram optical element is not visually recognized as a color by an external person, and the irritation is small. However, when the incident angle of outside light deviates from the predetermined incident angle α, the selected wavelength band shifts in a certain direction according to the Bragg's conditional expression, and even if mixed colors do not become an intermediate color and gradually It will be colored.

However, in the hologram optical element of the present invention, there is a visually impaired band as another selected wavelength band. Due to the action of this obtrusive band, the above-mentioned coloring due to the change of the angle is caused as described below. You can try to offset the changes. That is, when the selected wavelength band is shifted to the long wavelength side (reddish) due to the shift of the incident angle α, the invisible zone in the short wavelength band is similarly shifted to the visible light side to compensate for the bluish color. If the selected wavelength band shifts to the short wavelength side (being bluish), the invisible zone in the near-infrared region is also shifted to the visible light side and the redness is compensated to add a tint. Can be suppressed (solution of the second problem).

At this time, if the direction in which the band shifts due to the change in the incident angle α is one of the long wavelength band side and the short wavelength band side, the inadvertent band is correspondingly the short wavelength band. Alternatively, it may be on either one of the long wavelength band side. Needless to say, the information light emitted from the information light source in the above may be one that includes one of the selected wavelength bands in the visible light region, and the display image is displayed in the color of the information light. It As mentioned above, the first
According to the invention, it is possible to provide a good display device in which the background visually recognized by the viewer has no tint and the hologram visually recognized by an outsider does not have an exciting color.

On the other hand, in the display device according to the second aspect of the invention, the hologram optical element is provided with the light emitting means. Then, as described above, when the angle of the line of sight of an external person changes and the incident angle α of external light on the hologram optical element changes, the selected wavelength band of the hologram shifts. However, the light emitted by the light emitting means does not change. Therefore, it is possible to suppress the color change due to the shift of the selected wavelength band to a low level by setting the emission color of the light emitting means to the color lost by the shift of the selected wavelength band (shortest wavelength band or longest wavelength band). it can.

For example, when the line of sight of an external person changes and the selected wavelength band shifts to the long wavelength side, the red light in the selected wavelength band shifts to the near-infrared invisible zone side, and Although the blue light is shifted to the green side, the change in the color tone as a whole is weakened by setting the emission color of the light emitting means to the shortest wavelength band because the blue light of the light emitting means remains. Therefore, the color viewed by the external person from the hologram optical element remains close to the intermediate color and does not change to a stimulating color (solution of the second problem). In the display device of the second invention, the background viewed by the viewer may be a neutral color or a tint depending on the intensity of the emission color of the light emitting means. As described above, according to the second aspect of the present invention, it is possible to provide a display device capable of suppressing the stimulating external reflection of a hologram to an external person and making a color close to an intermediate color.

On the other hand, the display device according to the third aspect of the invention is provided with the light emitting means for emitting the light within the selected wavelength band of the hologram. Therefore, the light transmitted from the back side of the hologram optical element can compensate the band of the light not transmitted through the hologram (the selected wavelength band of the hologram) by the light emitted from the light emitting means. Therefore, the background visually recognized by the viewer due to the light transmitted through the screen becomes natural without any tint (the solution to the first problem).

When the hologram has a plurality of selected wavelength bands, it is preferable that the light emitting means normally emits light within the band of all the selected wavelength bands. This is because the viewer can visually recognize a background without color. In this case, when the light emitting means does not emit light within all the selected wavelength bands, the selected wavelength bands not emitted by the light emitting means are mixed to form a neutral color, Similarly, the viewer will be able to see the background without color. As described above, according to the third aspect of the invention, it is possible to provide a display device capable of providing a display (background) that is easy for a viewer to see.

[0029]

【Example】

Example 1 In this example, as shown in FIG. 1 and FIG. 2, the scene 31 of the back side is visually recognized by the light 31 transmitted from the back side of the screen 10 and the light 33 reflected from the front side of the screen is superimposed on the background. 1 is a head-up display as a display device 1 configured to visually recognize a display image. The display device 1 includes an information light source 21 that emits the display image and a semitransparent reflective hologram optical element 11 that diffracts the light 32 emitted from the information light source 21.

The hologram optical element 11 has four selection wavelength bands, and the selection wavelength bands are as shown in FIG. 3 at an incident angle (50 °) at which the viewer 81 or the information light 33 visually recognizes. Selected wavelength bands 41 to 43 of three visible lights having a chromaticity relationship that form an intermediate color (maximum wavelength = 448n
m, 543 nm, 630 nm) and an invisible selective wavelength band in the ultraviolet region (maximum wavelength = 360 nm). That is, in the visible light selection wavelength bands 41 to 43, 400 to 500 n
m, 500 to 570 nm, and one belonging to each of the ranges of 570 to 760 nm are included.

The wavelength range for selection of the visually impaired is 360 nm, which is in the range of 360 nm to 380 nm. Then, the hologram optical element 11 includes a plurality of hologram elements 11
It is a multilayer hologram device in which 1,112 are laminated.
As shown in FIG. 2, the display device 1 of this example is a head-up display in which a hologram optical element 11 is arranged on a windshield of a vehicle to form a display screen 10.

The display screen 10 of the display device 1 is mounted on the windshield at an angle φ (FIG. 1) with the horizontal plane H. In the screen 10, the plate glasses 191 and 192 are bonded together by an intermediate layer 193 such as polyvinyl butyral, and the intermediate layer 19
The hologram optical element 11 as a combiner is enclosed between the plate 3 and the plate glass 192. The hologram optical element 11 includes a pair of hologram elements 111, 11
2, and the hologram elements 111 and 112 are manufactured by the method described below.

In the hologram elements 111 and 112, a hologram original plate 51, which is obtained by coating and drying, for example, dichromated gelatin on a polyester film as a photosensitive material, is exposed by the optical system shown in FIG. That is, the laser light 71 emitted from the laser light source 61 is split into two by the beam splitter 62, and one light 721 is reflected by the reflecting mirror 631 and the convex lens 641.
The hologram original plate 51 is irradiated with the spherical wave 723 via the light source 722 and the other light 722 is reflected by the reflecting mirror 632 and the convex lens 642.
It is irradiated from the other side of the hologram original plate 51 as a spherical wave 724 via the. After exposing as above, normal development,
The hologram elements 111 and 112 are completed through a fixing process.

The wavelength of the laser light 71 in FIG.
The incident angles of the spherical waves 723 and 724 with respect to the hologram original plate 51 depend on the optical system during reproduction (the information light source 21 and the position of the eyes of the viewer 81, the characteristics of the information light source 21) shown in FIG. It is determined by the Bragg conditional expression in consideration of the shrinkage ratio and the like.

The two hologram elements 111 and 112 are
Each has two different selection wavelength bands in the four selection wavelength bands. Then, as shown in FIGS. 1 and 2, when the information light 32 emitted from the information light source 21 enters the hologram element 11 at approximately 50 °, the hologram optical element 11 has a predetermined reflection angle of approximately 62.5 °. Reflected into the eyes of the viewer 81. The information light 32 may include any one of the three visible light selection wavelength bands 41 to 43.

On the other hand, when the outside person 82 reflects the external light to visually recognize the hologram optical element 11, as shown in FIG. 2, the angle between the line of sight 83 and the hologram optical element 11 varies depending on the position. Change. Normally, the range of the angle γ is −5 when the line of sight S corresponding to the predetermined reflection angle of 62.5 ° is set to the reference position (0 °), as shown in FIG.
It is sufficient to cover the angular range from ° to + 64 °. When the angle γ is 0 °, the external light reflected from the hologram optical element 11 has the spectrum of the selected wavelength band shown in Table 1 (A). And the outsider 8
2 visually recognizes the hologram optical element 11 as a neutral color due to the color mixture of the selected wavelength bands 41 to 43 of visible light shown in FIG.

Next, when the angle γ is -5 °, the wavelength of the selected wavelength band shifts to the spectrum shown in Table 1 (B) due to the angle selectivity of the hologram. Then, the selected wavelength band of the visible light has the chromaticity relationship (selected wavelength bands 411, 421, 422) shown in FIG.
The hologram optical element 11 seen by 2 can maintain almost an intermediate color.

On the other hand, when the angle γ becomes + 64 °, the selected wavelength band is largely shifted to the spectrum shown in Table 1 (C). Then, when γ = 0, the visually impaired selection wavelength band that was 360 nm is newly changed to the visible light selection wavelength band 44 (FIG. 5) of 428 nm. As a result, as shown in FIG. 5, four selected wavelength bands 412, 422, 43
2, 44 can show an almost intermediate color due to the color mixture, and the hologram optical element 11 seen by an outsider remains almost an intermediate color.

Further, the external scene (background) visually recognized by the viewer 81 is tinted to the complementary colors of the four selected wavelength bands 41 to 43 shown in FIG. Become. As described above, according to this example, the outside person 8
It is possible to provide the display device 1 in which the viewer 2 cannot see the background in an exciting color and the viewer 81 can see the background in a natural color.

[0040]

[Table 1]

Embodiment 2 This embodiment is another embodiment in which the visually impaired selection wavelength band is changed from Embodiment 1. As shown in Table 2, the maximum wavelength of the inadvertently selected wavelength band of the hologram optical element 11 of the display device 1 of this example is 390 nm at the predetermined incident angle (62.5 °).

[0042]

[Table 2]

Then, the angle γ at which the external person 82 visually recognizes the hologram optical element 11 is changed from 0 ° to −5 °, +64.
When changed to °, from Table 2 (D) to (E),
As shown in (F), the chromaticity relationships of the four selected wavelength bands are as shown by the circles in FIGS. 7 to 9. As can be seen from FIGS. 7 to 9, when the four selected wavelength bands are mixed, the colors are all close to the neutral color, and the same effect as that of the first embodiment can be obtained. Others are the same as those in the first embodiment.

In the first and second embodiments, the hologram optical element 11 has two hologram elements (layers).
It is not limited to 3 pieces (layers) or 4 pieces (layers)
Or a single multiple hologram element.

Example 3 In this example, as shown in FIG. 10, the hologram optical element 12 in Example 1 is replaced with the hologram element 121 and the light emitting means 1.
22 is another embodiment of the present invention. Then, the light emitting means 122 emits blue light of 380 nm to 500 nm. The hologram element 121 has three selected wavelength bands at a predetermined incident angle (62.5, γ = 0 °), and their maximum wavelengths are 448 nm, 543 nm, 6
It is 30 nm (namely, the invisible zone of Table 1 and Table 2 is excluded).

When the angle of incidence of light on the hologram element 121 changes, it changes as shown in Tables 1 and 2 except for the invisible zone (γ = 0 °, 360 nm, 390 nm) which does not exist in this example. As a result, the reflected light due to the external light caused only by the hologram element 121 seen by the outsider 82 becomes reddish. However, the hologram optical element 12 of the present example is additionally provided with the light emitting means 122, and since the light emitting means 122 emits blue light, the reflected light of the hologram element 121 and the colored light of the light emitting means 122 are mixed. Are held near the neutral color.

Therefore, the hologram optical element 12 visually recognized by the outside person 82 by the external light does not have a stimulating color. The external scene (background) seen by the viewer 81 of the display device 1 is slightly bluish in correspondence with the strength of the light emitting means 122, but does not cause much discomfort. Others are the same as those in the first embodiment.

Example 4 In this example, as shown in FIG. 11, in Example 3, the light emitting means 132 of the hologram optical element 13 emits light within the selected wavelength band of the hologram element 131.
Two examples. For example, if the selected wavelength band of the hologram element 131 is blue, the light emitting means 132 also emits blue light. Then, the external scene seen by the viewer 81 becomes a neutral color by mixing the complementary color (without blue) of the selected wavelength band transmitted through the hologram element 131 and the blue color of the light emitting means 132, and the viewer 81 sees the background naturally. It will be visible in various colors.

However, in the case of this example, an outside person 8
2, the hologram optical element 13 is visually recognized as blue. Others are the same as in the first embodiment.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of a display device according to a first embodiment.

FIG. 2 is a diagram showing the arrangement of the display device of the first embodiment in a vehicle and the position of the line of sight of an external person looking at the hologram optical element.

FIG. 3 is a chromaticity diagram of an XYZ color system in a selected wavelength band of the hologram optical element of Example 1 (angle γ of the line of sight of an external person is 0 °).
When).

FIG. 4 is a chromaticity diagram of an XYZ color system in a selected wavelength band of the hologram optical element of Example 1 (the angle γ of the line of sight of an external person is −5).
°)).

FIG. 5 is a chromaticity diagram of an XYZ color system in a selected wavelength band of the hologram optical element of Example 1 (the angle γ of the line of sight of an external person is +6).
At 4 °).

FIG. 6 is an optical system in the exposure process of the hologram element of Example 1.

FIG. 7 is an XYZ color system chromaticity diagram of the hologram optical element of Example 2 (when the angle γ of the line of sight of an external person is 0 °).

FIG. 8 is an XYZ color system chromaticity diagram of the hologram optical element of Example 2 (when the line of sight of an external person is −5 °).

FIG. 9 is an XYZ color system chromaticity diagram of the hologram optical element of Example 2 (when the angle of the line of sight of an external person is + 64 °).

FIG. 10 is a system configuration diagram of a display device according to a third embodiment.

FIG. 11 is a system configuration diagram of a display device according to a fourth embodiment.

[Explanation of symbols]

1. ． ． Display device, 11. ． ． Hologram optics, 21. ． ． Information light source,

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-6-95575 (JP, A) JP-A-4-291221 (JP, A) JP-A-5-2359 (JP, A) Actual development Sho-58- 180522 (JP, U) Tokumei Hyo 8-506772 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G03H 1/26 G02B 5/32

Claims (14)

(57) [Claims] 1. A display device configured to visually recognize a scene on the back side by light transmitted from the back side of the screen, and visually recognize a display image on the background by light reflected from the front side of the screen, The display device includes an information light source that emits the display image and a light-transmitting reflective hologram optical element that diffracts the light emitted from the information light source, and the hologram optical element is at least 4 Has one or more selected wavelength bands, and this selected wavelength band is
At the incident angle at which the viewer visually recognizes the information light, there are three or more visible light bands in a chromaticity relationship that form approximately a neutral color, and a short wavelength band or near the visible light band between the ultraviolet region and the ultraviolet region. A display device, comprising: a visually impaired band including at least one of long wavelength bands in the infrared region. 2. The method according to claim 1, wherein the plurality of visible light selection wavelength bands include 400 to 500 nm and 500 to 570.
nm, and at least one or more belonging to the respective ranges of 570 to 760 nm are included. 3. The display device according to claim 1 or 2, wherein the visually impaired selective wavelength band is a selective wavelength band in a range of 350 nm to 400 nm. 4. The display device according to claim 3, wherein the selection wavelength band for the visually impaired is in a range of 360 nm to 380 nm. 5. A display device configured to visually recognize a scene on the back side by light transmitted from the back side of the screen and visually recognize a display image on the background by light reflected from the front side of the screen, The display device includes an information light source that emits the display image and a light-transmitting reflective hologram optical element that diffracts the light emitted from the information light source. The hologram optical element is a hologram. The hologram has three or more selected wavelength bands in the visible light region that have a chromaticity relationship of forming approximately an intermediate color at an incident angle at which a viewer visually recognizes the information light. The display device, wherein the light emitting means emits light in the vicinity of the shortest wavelength band or in the vicinity of the longest wavelength band in the selected wavelength band. 6. The selected wavelength band according to claim 5, wherein the selected wavelength band is 380 to 500 nm, 500 to 570 nm, and 570.
A display device comprising at least one selected wavelength band belonging to each range of ˜760 nm. 7. The display device according to claim 5, wherein the light emitting means emits light in the vicinity of the shortest wavelength band in the selected wavelength band of the hologram. 8. A display device configured to visually recognize a scene on the back side by light transmitted from the back side of the screen, and visually recognize a display image on the background by the light reflected from the front side of the screen, The display device includes an information light source that emits the display image and a light-transmitting reflective hologram optical element that diffracts the light emitted from the information light source. The hologram optical element is a hologram. A display device comprising: a light emitting means, the light emitting means emitting light within a selected wavelength band of the hologram. 9. The hologram according to claim 8, wherein the hologram has a plurality of selected wavelength bands, and the light emitting means is a multicolored light emitting means for emitting light within all the selected wavelength bands. A display device characterized by. 10. The display device according to claim 5, wherein the light emitting means is an active element driven by electric energy or the like. 11. The passive light emitting device according to claim 5, wherein the light emitting device includes a light emitting dye such as a fluorescent dye, a phosphorescent dye, and a phosphorescent dye that emits light upon receiving light. A display device characterized by being. 12. The display device according to claim 1, wherein the hologram optical element includes a multilayer hologram device formed by stacking a plurality of hologram elements. 13. The hologram optical element according to any one of claims 1 to 11, wherein the hologram optical element includes a single-layer hologram element, and the hologram element covers both a visible light region and an ultraviolet region. A display device, which is manufactured by using a light-sensitive material having high sensitivity, or a light-sensitive material having high sensitivity in both visible light region and near-infrared region. 14. A head-up display device according to any one of claims 1 to 13, wherein the hologram optical element is arranged on a windshield of a vehicle to form a display screen.