JPH0790729B2 - Vehicle display - Google Patents

Description

TECHNICAL FIELD The present invention relates to a vehicle display device using holography.

(Prior Art) Conventionally, driving information such as vehicle speed, mileage, inter-vehicle distance, remaining fuel amount, or time has been displayed by a meter or clock provided on the instrument panel, but recently drivers see this information. In addition, a display device has been considered in which such driving information is imaged in the front visual field outside the windshield so that the driver does not have to look away from the front visual field, and it is viewed so as to overlap with the foreground in the visual field. (For example, JP-A-57-182541), it is called a head-up display device.

In this type of head-up display device, a cathode ray tube is normally used to display the driving information, but the cathode ray tube itself has a certain depth, and when it is attempted to improve the visibility of the display, high brightness is required and the depth is further increased. Is longer and requires more space, and it is difficult to mount it near a narrow instrument.

On the other hand, in the head-up display device, an optical lens system that guides an optical image usually uses several thick lenses, which increases the weight and the installation space.

Therefore, the applicant of the present application proposed a vehicle display device using holography in order to reduce the size of the head-up display device (Japanese Patent Application No. 60-142434).

In other words, a Lippman hologram is used in the combiner of the head-up display device, a beam of light is applied to the hologram in which a surface object is recorded in advance to reproduce a part of the surface object, and the driving information is displayed by scanning the beam light. I decided to do it.

However, as is well known, the Lippmann hologram has wavelength selectivity, so that the display color that can be reproduced by the head-up display device is a single wavelength, that is, only one color, for example, a red color for warning display, a green color for instruction display, etc. It was not possible to display the display color systems separately, and the display was cold with one color, making it difficult to design on the model. Further, when a plurality of holograms are overlapped for multicolor display and a normal light bulb is used as a reproduction light source, light from a light emitting surface having a large area of the light bulb enters the hologram. In the light emitted from the light emitting surface, the light incident from the upper portion of the light emitting surface and the light emitted from the lower portion of the light emitting surface have different incident angles to the same point on the hologram. Due to this difference in the incident angle, color bleeding appears in the display image. That is, a hologram diffracts light of a certain angle and a certain wavelength,
At the same time, light having a wavelength slightly different from the predetermined wavelength at an angle slightly different from the predetermined angle also diffracts.

Light having a wavelength slightly different from the predetermined wavelength is included in an ordinary light bulb, and since the light emitting surface has an area, light having an angle slightly different from the predetermined angle is incident on the hologram. As a result, color bleeding occurs in which the periphery of the display image looks like a rainbow. Moreover, when the diffraction wavelengths of a plurality of holograms that are stacked are close to each other, color bleeding occurs over the plurality of holograms, making it very difficult to see the display.

(Object and Structure of the Invention) The present invention has been made in view of the above points, and an object thereof is to make a display color of a vehicle display device using holography multicolored without causing color bleeding. A first beam scanner that emits a beam of light of a first wavelength and sweeps a predetermined region; a second beam scanner that emits a beam of light of a second wavelength and sweeps the predetermined region; 1
A first hologram for displaying a virtual image of an alarm display by the beam light emitted from the beam scanner of the second and a second hologram for displaying a virtual image of a predetermined display other than the alarm display by the beam light emitted from the second beam scanner. And a beam light control means for controlling the emission and sweep of the beam light of the first and second beam scanners.

(Example) The present invention will be described below with reference to the drawings.

FIG. 1 shows the principle of producing a hologram used in the display device according to the present invention.

In the illustrated example, a Lippman hologram is used. 1 is a laser light source, 2 is a beam sprinter for splitting laser light, and 3 is one of the laser light split by the beam splitter 2 and is expanded to a Ω luminous flux for reference. Beam expander lens for making light L ₁ , 4 is float glass, 5 is dichromated gelatin as a hologram sensitive material attached to the float glass 4, 6 is a plane board which is a surface object,
Reference numeral 7 is an optical path conversion mirror for converting the optical path of the other laser light split by the beam splitter 2, 8 is a lens system for producing irradiation light L ₂ for irradiating the flat board 6, and L ₃ is object light from the flat board 6. .

The angles of incidence of the reference light L ₁ and the object light L ₃ on the dichroate gelatin 5 are θ _i and θ _R , respectively, and the dichroate gelatin 5 is separated from the plane board 6 by, for example, 1.5 m.

In order to apply the dichromate gelatin 5 to the float glass 4, first, the dichromate gelatin 5 is dropped on the float glass 4 and the float glass 4 is rotated. Then, the dichroate gelatin 5 is applied onto the float glass 4 by the centrifugal force (called a spin coating process). The thickness of the dichromated gelatin 5 can be adjusted by its viscosity and the rotation speed of the float glass 4.

In this way, when the reference light L ₁ and the object light L ₃ are incident on the dichroic gelatin 5 as the hologram sensitive material, interference fringes are multilayer-recorded substantially parallel to the direction of the photosensitive layer, and a hologram is completed.

FIG. 2 shows a hologram reproduced in this way. A hologram 10 is sandwiched between two transparent glasses 11 and 11 to form a combiner 12, and a laser beam from a laser scanner 13 causes its optical wavelength beam divergence angle ( )), The combiner 12 is scanned. In this case, the laser light becomes the reference light,
The incident angle (θ _i ) on the combiner 12 is set to be the same as the condition of the reference light L ₁ when forming the hologram 10. The eye E is placed near the position where the light from the combiner 12 has the diffraction angle θ _R.

When the combiner 12 is irradiated with the thin laser beam B emitted from the laser light scanner 13, the image of the flat board 6 (see FIG. 1) is visible to the eye E only at the portion where the beam B hits. Therefore, if the laser beam B is scanned in the X- and Y-axis directions and the on / off control is performed, an image 14 composed of a set of points hit by the beam B is obtained.
Looks distant. The image 14 appears 1.5 m in front of the combiner 12.

Therefore, if the laser beam B is swept by the laser light scanner 13 and the on / off control is performed by the driving information such as the vehicle speed and the engine speed, the display image of the driving information can be seen in the front.

FIG. 3A is a schematic diagram of an embodiment of the vehicle display device according to the present invention, and FIG. 3B is an enlarged view of the combiner 12 of FIG.

First, explaining the structure of the combiner 12 shown in FIG.
10a and 10b are holograms made of dichromated gelatin, and the holograms 10a and 10b have a two-layer structure sandwiching a silicone resin film 15, and are sandwiched by a transparent glass 11 and sealed by a sealing seal 16. .

The holograms 10a and 10b are manufactured in the same manner as described above with reference to FIG.
A flat board is recorded by making reference light of θa (for example, 25 °) incident using an r laser. The reproduction is performed by irradiating the same Ar laser at the incident angle θa.

The hologram 10b is manufactured by using a red He-Ne laser as a laser light source and injecting reference light of θb (for example, 41 °) to record a flat board. When reproducing, a He-Ne laser is applied at the same incident angle θb.

The holograms 10a and 10b may be separately produced and then bonded together, or after the hologram 10a is produced, a thin glass plate (about 0.1 mm) is placed on the dichroated gelatin of the hologram 10a, and the thin glass plate is further laminated. Apply dichromate gelatin and apply Holobram 10b there
May be produced.

FIG. 3A shows a vehicle display device using the hologram as described above, and 13a and 13b are laser light scanners each including a laser oscillator, a collimator, and an optical deflector, which are controlled by the controller 17. It A known rotating polygon mirror (called a holygon) may be used for scanning the laser light, or an acousto-optic modulator that changes the deflection angle of the laser light by using an acousto-optic effect may be used. . The laser light scanner 13a irradiates the combiner 12 with a green Ar laser at an incident angle θa, and the laser light scanner 13b irradiates a red He-Ne laser with an incident angle θb.

Here, when the combiner 12 is irradiated with the green Ar laser from the laser light scanner 13a at the incident angle θa, the hologram 10b is directly transmitted through the combiner 12, but is diffracted / reflected by the hologram 10a. Therefore, the green display image 14a is visible to the driver's eyes E. Similarly, when the red He-Ne laser is irradiated from the laser light scanner 13b to the combiner 12 at the incident angle θb, it is diffracted and reflected by the hologram 10b in the combiner 12, and the red display image 14b is seen by the driver's eyes E. The laser light scanners 13a and 13b are controlled by the controller 16, and the display color can be changed depending on the display purpose. For example, the warning display is displayed by the red laser light scanner 13b, the normal instruction display is displayed by the green laser light scanner 13a, and the multicolor display improves the visibility and appeal of the display image. .

In the above embodiment, the combiner uses a two-layer hologram, but the present invention is not limited to this, and a three-layer or more hologram may be used. In that case, a thin plate glass may be placed on the dichromated gelatin of the hologram once recorded, developed and fixed, and dichromated gelatin may be coated thereon to prepare the second and third stage holograms. According to this method, the hologram can be formed in multiple layers without increasing the thickness.

(Effects of the Invention) As described above, in the present invention, two holograms are laminated, and the light beams of two beam scanners for emitting and sweeping light beams of different wavelengths corresponding to the respective holograms are controlled. Since it is configured as described above, it is possible to change the display color depending on the display purpose, for example, it is possible to use a red type for the alarm display and a green type for the display other than the alarm. And the appeal power can be improved. Moreover, it is possible to match the emission angle of the beam light with the emission angle of the exposure light at the time of exposure of the hologram, and it is possible to obtain a display with no color blur and good visibility. In addition, since the display colors are multicolored, the degree of freedom in design is increased, and a display device with high commercialability can be provided.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a principle of producing a hologram used in a vehicle display device according to the present invention, FIG. 2 is a diagram for explaining a hologram reproduction principle, and FIG. 3 (a) is a vehicle-like display device according to the present invention. 1 is a schematic diagram of an embodiment, and (b) is an enlarged view of a combiner of the vehicle display device of (a). 10,10a, 10b …… hologram, 12 …… combiner, 13,13
a, 13b …… Laser light scanner, 14,14a, 14b …… Display image

Claims (1)

[Claims] 1. A first beam scanner which emits a beam light of a first wavelength and sweeps a predetermined region, and a second beam scanner which emits a beam light of a second wavelength and sweeps the predetermined region. A first hologram for displaying a virtual image of an alarm display by the light beam emitted from the first beam scanner, and a virtual image of a predetermined display other than the alarm display by the light beam emitted from the second beam scanner. For a vehicle, comprising: a combiner formed by laminating a second hologram for displaying a beam, and a beam light control means for controlling emission and sweep of beam light of the first and second beam scanners. Display device.