JPH1048562A - Holographic display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a small type display device allowing an observer to visually recognize a displayed picture without unnatural feeling. SOLUTION: Light emitted from an information display source provided on a main body part 51 is diffracted to an observer by a combiner 50 with hologram, and in order to make the observer visually recognize it, an angle to an optical axis from the observer to the displayed picture underastate of use of the combiner 50 is arranged to be from 70 to 110 degrees.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a holographic display device provided in a vehicle such as a vehicle, an aircraft, a ship, and the like, for projecting necessary information to an observer in the vehicle.

[0002]

2. Description of the Related Art In recent years, as a method of displaying information to a driver of a vehicle such as an automobile, a display device such as a head-up display (hereinafter, referred to as HUD) has been used. In this method, optical information projected from an information projection unit such as a liquid crystal display device is projected on a combiner including a half mirror or a hologram incorporated in a windshield of an automobile or the like, and a driver almost moves a viewpoint from a driving state. This allows information to be read without the need.

[0003] The above-mentioned HUD is based on specifications designed in advance before the production of automobiles and the like.
Since the information projection means including the light source is provided below the dashboard of the vehicle body and the combiner is provided on the windshield, the optical arrangement at the time of design becomes large. Also, it has been difficult to provide the HUD having the above configuration after the production of an automobile or the like.

Therefore, Japanese Patent Application Laid-Open No. HEI 8-11580 proposes a small HUD using a combiner provided separately from a vehicle body. This HUD is small in size even after production of an automobile or the like, and can exhibit the function of the HUD simply by being separately placed on a dashboard.

[0005] As such a HUD combiner,
Usually, a reflection type hologram is used. This is because the position of the information display source and the position of the observer are on the same plane side (inside the vehicle) with respect to the hologram.

[0006]

In an HUD in which a combiner is provided on a windshield of an automobile, the inclination angle of the combiner is the same as the inclination angle of the windshield, and falls in the direction of the driver. On the other hand, since the combiner is usually provided below the windshield, the display image is located slightly below the driver, and the driver's line of sight is looking down. Thus, the driver sees the combiner quite obliquely. In addition, the displayed image is often nearly perpendicular to the optical axis connecting the driver and the displayed image, or is rather inclined forward. Thus, when the direction of the line of sight is greatly inclined with respect to the combiner, or when the inclination of the combiner and the direction of the display image are reversed or the angle difference is large,
The observer may feel uncomfortable with the displayed image.

[0007] When the area is large like a windshield of an automobile, the inclination is not considered and the feeling of strangeness is not so large. However, in the case where a small combiner is separately provided as in the HUD disclosed in Japanese Patent Application Laid-Open No. H8-11580 and the like, a display image is viewed from a small opening, so that the angle difference between the combiner and the line of sight, Or,
The discomfort due to the difference between the inclination of the combiner and the inclination of the display image is further increased.

On the other hand, the use of a hologram as a combiner for these HUDs has been preferably proposed. That is, the hologram can diffract the light including the incident information in an arbitrary direction, and can add not only this diffraction function but also a lens function for displaying a display image at a long distance. In addition, since the half width of the diffraction spectrum is narrow, a display image with high luminance can be obtained without deteriorating the foreground luminance. Further, since the hologram has a wavelength selection function, an image of a desired color can be displayed at an arbitrary position. As described above, using a hologram as a combiner for a display device is preferable because the display function can be enhanced.

In the case where a hologram is used to enhance the display function, if the distance from the light source to the hologram cannot be sufficiently secured with respect to the size of the hologram, distortion or aberration will occur in the displayed image. Therefore, Japanese Patent Application Laid-Open No.
When a hologram is used for the combiner of the HUD disclosed in Japanese Patent Publication No. 580, there is a disadvantage that a display image with high visibility cannot be obtained.

An object of the present invention is to eliminate the above-mentioned disadvantages of the prior art, and to provide a holographic display device which has not been known.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and comprises a light source and a display for displaying information to be displayed, and generates information to be displayed as light. An information display source, and at least a combiner having a hologram arranged on a substrate and diffracting the light toward an observer and visually recognizing the observer as a virtual image; In a holographic display device having an end portion pivotally supported, the combiner is provided in an angle of 70 to 110 ° between an optical axis connecting an observer and a virtual image in a use state. A graphic display device is provided.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail with reference to the drawings. FIG. 1 is a schematic sectional view showing an example of the holographic display device of the present invention. This holographic display device illustrates a HUD mounted on a dashboard of an automobile. And, it mainly comprises a combiner 50, a main body 51, and a support 52. Body 51
Is held on a support table 52 mounted on a dashboard via a bottom surface having a shape similar to a ball joint often used for a camera platform as shown in the figure. Then, the spherical portion on the side of the main body 51 can be fixed by tightening it with a screw.
Therefore, the main body 51 is rotatable left and right, and is also movable in the vertical direction. The main body 51 can be installed regardless of the inclination of the installation surface such as the dashboard of the vehicle, and can be rotated in the direction desired by the viewer. Can be moved.

The combiner 50 includes a combiner holding component 5.
6, and is rotatably supported by the main body 51 via a combiner holding part 56 in the vicinity of the lower end thereof.

On the other hand, the information display source comprises a display 54 and a light source 53. Then, the light including the information emitted from the information display source is applied to the combiner 50 via the return mirror 55 provided in the main body 51. The light including the information incident on the combiner 50 at the incident angle θ ₁ is reflected and diffracted at the diffraction angle θ ₂ and emitted toward the observer (58: the optical axis direction connecting the observer and the virtual image). In this example, a plane mirror is used as the folding mirror. However, if a concave mirror is used, the displayed image can be enlarged.

FIG. 2 is a schematic sectional view (a) and a schematic front view (b) showing an example of a combiner according to the present invention. The combiner is formed by disposing a hologram 21 on a substrate 23 via an adhesive 24. Further, a cover film 26 is laminated on a surface of the hologram 21 opposite to the substrate 23 via a protective layer 25 and an adhesive 27.

In this embodiment, the substrate 23 has a thickness of 2.3 mm.
High heat-resistant transparent acrylic resin plate (Mitsubishi Rayon UT-1)
00), an acrylic adhesive as the adhesive 24, the protective layer 2
5 is a polyvinyl alcohol film, 5 is an ultraviolet curable adhesive as the adhesive 25, 2 is a cover film 26.
An acrylic film having a thickness of 00 μm was used.

The hologram 21 has a minimum width of 5 m
m ineffective areas 22 are provided. The non-effective area was formed by exposing only the non-effective area with non-coherent light prior to exposure of the hologram by the laser beam. The size of the substrate is about 85 mm in width and about 80 mm in height, and the size of the effective area of the hologram is about 75 mm in width,
It is about 70 mm long.

As described above, making the area of the effective region of the hologram smaller than the area of the substrate and providing an ineffective region having a width of, for example, 3 mm or more along the outer periphery of the substrate is required to prevent the entry of any substance from the outer periphery of the combiner. This is preferable because a change in the characteristics of the hologram due to the above can be minimized.

In the above hologram, light having a wavelength emitted from an information display source enters the hologram at an incident angle θ ₁ ,
Those that are exposed to diffracted by the diffraction angle theta _2. The combiner, the incident angle of the light emitted from the information display source is incident on the hologram to the theta _1, its use state are determined. Specifically, since the combiner is rotatably supported at its end by the main body, the combiner can be stored along the upper surface of the main body when not in use. Then, at the time of use, a combiner is raised to a position where the angle of incidence on the hologram becomes θ ₁ ,
It can be fixed by a stopper.

The position of the combiner at the time of use is set at an angle of 70 to 110 ° with respect to the optical axis (that is, the diffraction direction of the light from the information display source incident at θ ₁ by the hologram) connecting the observer and the virtual image. It is a position that forms an angle in the range.

The hologram used in this example has a thickness of 20 μm.
A reflection type hologram of a volume phase type was used, which was obtained by exposing a photosensitive material comprising an acrylic photopolymer. The exposure of the hologram is performed by dye laser light (wavelength 574.7 nm) using Rhodamine 6G and Kr laser light (wavelength 64).
(7.1 nm). The laser light is diverged by a spatial filter including an objective lens and a pinhole. Regarding the position of the divergence point, the distance from the divergence point to the hologram was 195 mm on the light source side (reference light side), and the distance from the divergence point to the hologram was 560 mm on the image side (object light side). Since the hologram of this example is of a reflection type, the two divergence points are arranged to face each other with the hologram photosensitive material interposed therebetween. The exposure angle is 37.9 ° on the light source side and −1.
8 °. After the laser exposure, ultraviolet irradiation and heat treatment were performed to produce a hologram.

The hologram thus obtained had diffraction peaks near 545 nm and 613 nm for incident light at 40 °, and the diffraction efficiencies were about 70% and 50%, respectively. The full width at half maximum of wavelength was about 10 nm. Further, as described above, when the distance from the center of the hologram to the center of the display body 54 was set to be 150 mm, a display image enlarged about twice was obtained.

In the display device of this embodiment, when the main body is held in a horizontal state, the combiner 50 having the holograms exposed as described above is displaced from the horizontal by θ ₃ = 80.
° is used. That is, in this setting, the combiner 50 is arranged so as to be inclined forward as viewed from the observer. The incident angle (θ ₁ ) of light on the optical axis from the center of the display body 54 to the center of the hologram of the combiner 50 is 40 °, and the diffraction angle (θ ₂ ) from the combiner to the observer is 0 °.

Accordingly, a holographic display device is obtained in which the combiner is perpendicular to the observer's line of sight, so that the holographic display device does not give a sense of discomfort when viewing the display. Also, since the difference between the incident angle to the combiner and the diffraction angle is as large as 40 °, a holographic display device with good visibility without unnecessary images such as surface reflection images without applying an anti-reflection coating on the surface of the combiner. Obtained.

The distance from the center of the display 54 to the center of the hologram combiner 50 was 150 mm. Also,
When the main body 51 is set horizontally, the direction from the observer to the center of the combiner is looking down at 10 ° from the horizontal.

In this embodiment, a DSTN-LCD having a two-layer structure of a display cell and a compensation cell is used as the display 54.
This display has a pitch of 0.45 mm, 64 dots × 32 dots, and has a polarizing plate attached so that light emitted in the combiner direction becomes S-polarized light. Further, a diffusion plate (not shown) is provided on the light source 53 side to reduce unevenness of the light source.

The light source 53 has a three-wavelength tube diameter of 2.6 mm,
There are two cold cathode tubes with a tube length of 60 mm. This cold cathode tube has 436 nm, 545 nm, 6
It has a thickness of 13 nm. And DSTN-LC
A green transmission filter considering the emission line spectrum of the cold-cathode tube is disposed at a portion corresponding to 48 dots × 32 dots between D and the diffusion plate, and a cold-cathode tube is disposed at a portion corresponding to 16 dots × 32 dots. In addition, a red transmission type filter that takes into account the emission line spectrum is arranged to enable color display in divided regions. In this way, a vivid two-color display was obtained in which the color tone of the display image was divided into a green region in a portion transmitted through the above-mentioned green transmission filter and a red region divided in a portion transmitted through the red transmission filter. If green and red diffracted light are mixed without using a filter, a yellow display image can be obtained with the hologram of this example.

FIG. 3 is a schematic sectional view showing another example of the holographic display device of the present invention. This example is a holographic display device constituted by a combiner using a transmission hologram. The configuration is almost the same as in the previous example except that the hologram is a transmission type.

The arrangement of the combiner 50 in the use state of the present embodiment is also set such that θ ₃ = 80 ° with respect to the horizontal when the main body is held in a horizontal state similarly to the previous embodiment. It was inclined forward as seen from the observer. The incident angle (θ ₁ ) of light on the optical axis from the center of the display body 54 to the center of the hologram of the combiner 50 is 30 °, and the transmission diffraction angle (θ ₂ ′) from the combiner to the observer is 0 °.

Accordingly, a holographic display device is obtained in which the combiner is perpendicular to the line of sight of the observer, so that the holographic display device does not cause any discomfort when viewing the display. Also, since the difference between the incident angle to the combiner and the diffraction angle is as large as 30 °, a holographic display device with good visibility without unnecessary images such as surface reflection images without applying an anti-reflection coating on the surface of the combiner. Obtained.

The distance from the center of the display 54 to the center of the hologram combiner 50 was 150 mm. Also,
When the main body 51 is installed horizontally, the direction from the viewer to the center of the combiner is 10 ° below the horizontal.

The hologram used in this example has a thickness of 10 μm.
Is a volume phase transmission hologram obtained by exposing a photosensitive material made of an acrylic photopolymer. The hologram was exposed by a dye laser beam (wavelength: 551 nm) using rhodamine 110. The laser light is diverged by a spatial filter including an objective lens and a pinhole. The position of the divergence point is 135 m on the light source side (reference light side) from the divergence point to the hologram.
m and the distance from the divergence point to the hologram on the image side (object light side) was 270 mm. Since the hologram of this example is of a transmission type, the two divergence points are arranged on the same side of the hologram photosensitive material. The exposure angle is 30 ° on the light source side and 0 ° on the light source side with respect to the center of the optical axis. After the laser exposure, ultraviolet irradiation and heat treatment were performed to produce a hologram.

The hologram thus obtained had a diffraction peak near 545 nm with respect to the incident light at 30 °, and the diffraction efficiency was about 80%. Further, as described above, the distance from the center of the hologram to the center of the display body 54 is 13
When arranged so as to be 5 mm, a display image enlarged about twice was obtained.

In the second example, since a monochromatic hologram is used, the color tone of the displayed image is a monochromatic green color. No filter for segmentation as in the previous example is used. As a matter of course, if the hologram is exposed in two colors and the above-described filter is used, two-color display is possible. In addition, by appropriately adjusting the relationship between the intensity of the emission line of the light source corresponding to green and red, the transmittance of the filter, and the diffraction efficiency of the hologram, display images of various colors such as green, yellow green, yellow, orange, and red can be obtained. Obtainable. Furthermore, if a hologram exposed by three wavelengths corresponding to three colors of blue, green and red is used, a full-color display image can be obtained similarly.

In the case of performing color display of the above-described display image, if the distance from the combiner to the display image is the same for each color, color display can be performed on the same plane. It is possible to obtain three-dimensional images having different viewing distances of the images.

The information display source of the holographic display device according to the present invention may be any device having a function of emitting light for display. The information display source used in the above example is a liquid crystal display device or the like comprising a so-called light receiving type display device. Cold cathode tube, hot cathode tube (H
CT), a fluorescent display tube (VF), a light emitted from a light source such as a halogen lamp, a light emitting diode, a semiconductor laser, or the like, or a combination of these functions.

In this case, the light source is either a light source having a bright line or a combination of a light source having a wide spectral width and a narrow band-pass filter. By making the diffraction wavelength of the light diffracted by the hologram in the direction of the person approximately equal to the wavelength of the emission line of the light source or the wavelength of the narrow band filter, the light containing information is efficiently diffracted by the hologram, and the foreground luminance , And a display image with high brightness can be obtained.

In particular, a transmissive liquid crystal display device can be preferably used as the display in the present invention. If a dot matrix type element is used as a transmissive liquid crystal display element,
Although the contrast and the transmittance are slightly inferior, various displays of free contents are possible. On the other hand, if a segment type transmissive liquid crystal display element is used, the display content is fixed to some extent, but a very high contrast and bright display can be achieved.

As the transmissive liquid crystal display element, a TN type liquid crystal display element can be used, but an STN type liquid crystal display element is preferable in order to achieve a high contrast display. In particular, the DSTN type liquid crystal used in the above two examples is used. The display element is preferable because higher contrast display can be obtained. In addition, a film-stacked STN-type liquid crystal display device having a similar compensation effect using a uniaxial polymer film instead of the compensation cell can be used, but a DSTN-type liquid crystal display device is preferable in consideration of temperature dependency. . In addition, a temperature sensor is provided near the display body of the main unit, and control means for compensating for changes in the characteristics of the display body due to temperature changes based on a signal from the temperature sensor is provided, thereby compensating for changes in the characteristics of the liquid crystal display element due to environmental temperature changes It is also possible. In this way, a holographic display device with little change in characteristics can be realized even in a case where the operating temperature range is wide such as in a vehicle.

Further, it is preferable that the light including the information to be displayed, which is transmitted through the transmission type liquid crystal display element and enters the combiner, is S-polarized light. Generally, the diffraction efficiency of a hologram has polarization dependence, and the S-polarized light has higher diffraction efficiency than the P-polarized light. Therefore, if S-polarized light is used, light containing information can be diffracted more efficiently by the hologram, and a holographic display device with a high light utilization factor can be realized.

When a display image is displayed in color, a color filter and a transmission type TN type liquid crystal element or ST
A color liquid crystal display device or the like comprising an N-type liquid crystal display device or the like can be preferably used, and a light beam emitted from one light source can be irradiated as a light beam of a desired color.

In this way, light of a plurality of colors can be emitted from the same information display source, and when these lights of a plurality of colors are displayed simultaneously, the display images are displayed in an overlapping manner.
Conversely, in order to prevent the display images from being overlapped, a plurality of colors of light may be prevented from being simultaneously irradiated by a combination of a color filter and a light source as needed or by controlling a color liquid crystal display element.

Alternatively, the light source itself may be patterned and arranged to generate specific information as light without using a light-receiving display element. In the case where the above-mentioned light source is used in combination with the light receiving type display element, appropriate light collimating means such as a lens system and a curved reflecting mirror, and appropriate light guiding means such as a light guide plate are provided between the light receiving type display element and the light source. It may be arranged. Further, in the optical path before the light is projected on the hologram, if necessary, a light polarizing means or KN
A nonlinear optical element such as O ₃ may be provided.

In the above two examples, the driving circuit of the DSTN-LCD and the driving circuit of the cold cathode tube are housed in the circuit section 57. The circuit section includes a circuit for processing and controlling signals from a temperature sensor, a light receiving sensor, and the like (not shown), and an interface circuit with the outside. The circuit is connected to an external connection cable (not shown) via a connector. I have. A heat seal (not shown) is used to connect the DSTN-LCD to the drive circuit of the DSTN-LCD. However, if the drive circuit is made of COG (chip-on-glass) or TAB (tape automated bonding), the size can be further reduced. It becomes possible. In the above two examples, display data was transmitted serially in order to reduce the number of external connection signal lines. However, it is also possible to mount a storage device or a CPU inside the main body and display a corresponding pattern by a code. is there. Further, the transmission method can use not only the cable but also wireless or infrared rays. For example, it is also possible to have a function of receiving FM multiplex broadcasting inside the main body and display the information.

In addition to the above, two volume parts (not shown) are provided as circuit components for manual adjustment of brightness and contrast, and are arranged so that a knob can be turned from the side surface of the main body 51, and the above-mentioned drive circuits are respectively provided. Connected to.

As described above, if the main body is provided with the control means for automatically adjusting the brightness of the light source based on the light receiving sensor and the surrounding brightness and / or the control means for manually adjusting the brightness of the light source, the brightness of the environment can be improved. It is possible to obtain a display image having a brightness corresponding to the brightness, and it is also possible to adjust the brightness manually, so that the brightness can be adjusted as desired by the individual, and a holographic display device with good visibility can be realized.

Also, if a control means for adjusting the contrast of the display body separately from the main body and / or the main body is provided, a display image with good contrast can always be obtained.
A holographic display device with good visibility can be realized.

The combiner according to the present invention comprises at least a hologram arranged on a substrate. As this substrate, a transparent substrate is preferable because it can be used for both a transmission hologram and a reflection hologram, and a foreground visual field can be secured. The transparent substrate is referred to as a transparent substrate including not only a completely transparent substrate but also a substrate partially transmitting light. For example, not only a transparent glass plate having no color but also a glass plate colored with bronze or green can be used as the transparent substrate. In addition, the material is not only glass, acrylic, polycarbonate,
Polyvinyl chloride, polyolefin, diethylene glycol bisallyl carbonate, polystyrene, methyl methacrylate-styrene copolymer resin, styrene-acrylonitrile copolymer resin, poly (4-methylpentene-
The substrate may be a synthetic resin substrate as in 1) or a transparent crystal.

As the optical characteristics of the substrate, it is desirable that the refractive index is close to that of the hologram, and the refractive index is 1.44 to 1.64, but the noise due to the reflection generated at the interface between the substrate and the hologram is small. This is preferable in that respect. Further, it is preferable that haze (haze value) is small and light transmittance is large. If the haze is large and the light transmittance is small, it is difficult for the light to sufficiently enter the hologram, and the brightness of the displayed image is reduced, making it difficult to see. It is desirable that the birefringence is low. When the birefringence is high, the display image may be degraded due to the deterioration of the alignment of the polarization plane.

This substrate may be a film having a thickness of 1 mm or less, or may be a block having a thickness of several cm. If it is too thin, it may be difficult to handle it. It is difficult to reduce the size and weight. Further, it is preferable to use a substrate having excellent heat resistance and cold resistance depending on use environment conditions. It is particularly preferable to use a transparent resin substrate having a thickness of about 0.5 to 3.0 mm from the viewpoint of forward visibility and reduction in size and weight.

The combiner in the present invention preferably has a structure in which a hologram is laminated between two transparent substrates via an adhesive or an adhesive. Thus, the hologram can be prevented from the external environment and abrasion. If at least one of the two transparent substrates is a transparent film having a thickness of 1 mm or less, both protection and weight reduction can be achieved.

Further, by interposing an interfacial protective layer between the hologram and the pressure-sensitive adhesive or the adhesive, it is possible to prevent the characteristics of the hologram from being affected by the pressure-sensitive adhesive or the adhesive. As such a protective layer, a polyvinyl alcohol film or the like can be preferably used.

Furthermore, when the wear resistance of the substrate of the present invention is insufficient, a hard coater may be applied to the surface of the combiner if necessary, thereby realizing a combiner having excellent wear resistance.

If at least one of the substrate, the hologram, the adhesive, the adhesive, and the protective layer contains at least one of an ultraviolet absorber, an ultraviolet stabilizer, and an antioxidant,
Even in an environment exposed to ultraviolet rays, such as in a vehicle, a holographic display device with excellent reliability can be realized without impairing the properties of the respective materials.

The hologram used in the present invention is usually several tens.
mm to several hundreds mm square area, several μm to several tens μm
m. Such a hologram is desirable in that a volume / phase type hologram such as a Lippmann type can obtain a high diffraction efficiency.
A hologram such as a rainbow type can be widely used. Also, as a hologram material,
Various photosensitive materials such as photopolymers such as polyvinyl carbazole and acrylics, gelatin dichromate, photo resists and silver salts can be used.

Further, as the hologram of the present invention, a hologram that is multiple-exposed with light of a plurality of wavelengths or a hologram that is obtained by laminating a plurality of holograms that are exposed with light of one or more wavelengths is used. , Multi-color display is possible. Further, by recording a diffraction grating corresponding to an off-axis concave mirror or convex lens, a display image can be displayed in a distantly enlarged manner.

In the holographic display device of the present invention, the tilt angle of the combiner with respect to the line of sight becomes substantially perpendicular to the optical axis connecting the display virtual image and the observer in an angle range of 70 to 110 ° in use. There is no discomfort when viewing the displayed image. In order to satisfy such an angle condition, considering that the line of sight of the observer is almost horizontal or slightly looking down in the case of a general holographic display device, when the main body is held in a horizontal state, The combiner may be substantially upright or inclined in the forward direction of the observer.

In the present invention, as in the above example, the absolute value of the incident angle of light from the information display source to the hologram is larger than the absolute value of the diffraction angle from the hologram to the observer by 20 ° or more. An optical arrangement is preferred. This is because the diffraction image by the hologram and the surface reflection image of the transparent substrate provided with the hologram are completely separated, and a holographic display image with good visibility without a double image can be obtained.
Therefore, it is not necessary to apply an antireflection film in order to prevent a surface reflection image, and a low-cost holographic display device can be realized.

Further, it is preferable that the main body and the support are connected by a ball joint or the like so that the main body can freely rotate with respect to the support as in the above example. That is,
In the display device of the present invention, a main body provided with an information display source and a combiner are integrated. Then, when the display device is in use, the distance and the optical angle arrangement between the combiner and the information display source are kept constant. Therefore, the hologram reproduction condition can be kept in an optimal state. The connection structure as described above facilitates changing the inclination angle of the combiner with respect to the horizontal while keeping the arrangement of the combiner and the information display source constant. For example, when observers of various heights make adjustments for observing a display image at a height suitable for each person, if the inclination angle of the combiner with respect to the horizontal is changed at the above-mentioned connecting portion, the observer can view the image. To change the height of the displayed image.

Further, the combiner according to the present invention is of a retractable type and can be stored along the upper surface of the main body, so that the combiner can be folded down when not in use.
It can be more compact. Further, a holographic display device excellent in design can be realized. It should be noted that the operation of raising the combiner from a state of being stored along the upper surface of the main body to the use state can be performed by pressing the upper part of the combiner to open and close with a single touch so as to be in a standing state at a predetermined angle. Is often preferred. If a buffer mechanism is provided so that the movement of the combiner does not suddenly change at that time, the movement of the combiner can be made extremely smooth, and deformation and fatigue of parts and materials due to sudden movement can be prevented. Can be. Further, a switch interlocked with the movement of the combiner is provided, and when the combiner is erected, the power source of the light source and / or the display is connected, and when the combiner is stored along the upper surface of the main body, the light source and / or the display is turned off. If the power supply is cut off, no separate manual switch is required and no power is consumed when the combiner is in the stowed state, which is economical, has a small number of parts and is inexpensive. Further, a holographic display device which is easy to use and excellent in design can be realized.

When the holographic display device of the present invention is used in a vehicle, the display device is mounted on the dashboard as in the above example, and is incorporated in the dashboard. When used, the holographic display device can be realized to be extremely compact and excellent in design if the holographic display device is folded down and stored along the dashboard.

When the information display source and the combiner are integrated (via the main body) as in the present invention, the distance between the combiner and the information display source is short. When a hologram having a magnification is used as a combiner, a display image is generally distorted if the distance between the combiner and the information display source is short. In order to reduce such distortion, it is preferable to optimize exposure conditions such as an exposure optical arrangement and to perform aspherical wave exposure using a cylindrical lens or the like. If the distortion still does not completely disappear, the shape of the information displayed on the display body is deformed in advance so as to correct the image distortion of the virtual image obtained by being diffracted by the hologram. A display image can be obtained. As such a deformation, it is preferable to deform the corresponding horizontal line displayed on the display body into a multi-order curve so that the horizontal line of the display image becomes a straight line. The following curve is effective enough.

When a hologram having a non-specular reflection arrangement and a magnification is used as in the present invention, an obtained display image may be greatly inclined with respect to the line of sight. Such a display image not only has a sense of discomfort as described above, but also causes dynamic image distortion when the observer moves the position of the viewpoint.
In such a case, the inclination of the display image with respect to the line of sight can be corrected by inclining the angle formed by the surface of the display body with respect to the optical axis from the information display source to the combiner from a right angle. The angle varies depending on the magnification of the hologram and the optical arrangement of the holographic display device.
About 50 ° is preferable.

When the holographic display device of the present invention is applied to a vehicle, the information to be displayed is appropriately selected according to the display application, and includes a speedometer, a tachometer, a shift lever display of a vehicle, and various types of information. Examples include warning lamps, navigation information, and information on attached devices such as air conditioners and audio devices. Further, it is of course possible to display information from outside the vehicle such as road information and parking lot availability information. Also, for aircraft and ships, various information related to vehicle operation and operations, such as position and orientation information such as latitude, longitude, altitude, direction of travel, weather information, radar obstacle information, fish finder information, etc. Conceivable. Note that the observer is mainly a driver of a vehicle such as a vehicle, but may include a passenger seat and other passengers, and all of them.

In the above description, the present invention has been described focusing on an example in which the present invention is applied to an HUD for an automobile, but the application of the holographic display device of the present invention is not limited thereto. For example, the present invention can also be used for a virtual image corner marker arranged on a dashboard or a rear tray to indicate a corner position of a vehicle. In addition to vehicles, the present invention can be widely applied to display devices using holograms, such as a prompter and a game.

[0066]

According to the holographic display device of the present invention, since the information display source and the combiner are provided in the main body and integrated, a very compact holographic display device can be realized. In this case, the positional relationship between the information display source and the combiner is fixed such that the angle of incidence of light from the information display source to the combiner and the distance from the information display source to the combiner are fixed so that the hologram is fixed. Can always be kept in an optimal condition.

According to the holographic display device of the present invention, since the angle of the combiner is in the range of 70 to 110 ° with respect to the optical axis connecting the display virtual image and the observer, the inclination angle of the combiner with respect to the line of sight is almost perpendicular. When viewing the display image, the sense of discomfort can be reduced. Further, since the display image is generally perpendicular to the line of sight, the inclination angle of the display image is almost equal to the inclination angle of the combiner, and a display image without a sense of incongruity can be obtained.

As described above, according to the present invention, it is possible to realize a holographic display device which is comfortable and has excellent visibility.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of a holographic display device of the present invention.

FIG. 2 is a schematic sectional view (a) and a schematic front view (b) showing an example of a combiner according to the present invention.

FIG. 3 is a schematic sectional view showing another example of the holographic display device of the present invention.

[Explanation of symbols]

 21: Hologram effective area 22: Hologram non-effective area 23: Substrate 24: Adhesive 25: Protective layer 26: Cover film 50: Combiner 51: Main body 52: Support 53: Light source 54: Display 55: Folding mirror 56: Combiner holding part 57: Circuit part 58: Light containing information

Claims (5)

[Claims] An information display source comprising a light source and a display body for displaying information to be displayed, the information display source generating information to be displayed as light, and a virtual image arranged on a substrate and diffracting the light toward an observer. A holographic display device comprising at least a combiner having a hologram to be visually recognized by an observer, and an end of the combiner being pivotally supported on a main body provided with the information display source, wherein the combiner is in use. The angle between the optical axis connecting the observer and the virtual image is 7
A holographic display device provided in a range of 0 to 110 °. 2. The holographic display device according to claim 1, wherein said combiner is substantially upright or inclined forward of the observer. 3. The hologram according to claim 1, wherein an absolute value of an incident angle of light from the information display source to the hologram is larger than an absolute value of a diffraction angle from the hologram to an observer by 20 ° or more. Graphic display device. 4. The holographic display device according to claim 1, wherein said hologram is recorded with a diffraction grating corresponding to an off-axis concave mirror or convex lens. 5. The tilt angle of the combiner is adjustable so that the height of the virtual image can be changed when viewed from an observer. At the time of adjusting the tilt angle of the combiner, light from the information display source enters the combiner. 2. The combination of claim 1, wherein the angle and the distance from the information source to the combiner are kept constant.
The holographic display device according to any one of items 1 to 4,