JPH0348809A - Display device for vehicle - Google Patents

Abstract

PURPOSE:To obtain a display device for vehicle whose displayed image is not a double image for the eyes of a driver by providing a hologram which diffracts light having a specified incident angle previously set at a specified diffractive angle in a front glass. CONSTITUTION:The light 11, out of displaying light from an image display unit 1, is made incident on a point A1 at the incident angle theta1 and reflected toward the eyes 3 of the driver, then the image 21 is formed on a point P on the extension l1 of the reflected light 11. Meanwhile, the light 12 reflected on the surface 2B of the front glass 2 on the outside of a vehicle which is the cause of the double image is made incident on a point A2 on the surface 2A on the inside of the vehicle at the incident angle theta2 and incident in the front glass at a refractive angle theta3. The incident light 12 is made incident on a point C on a transmission type hologram 4, diffracted at the diffractive angle theta4 and reflected on the surface 2B on the outside of the vehicle, then it is refracted at the refractive angle theta5 from a point A3 on the surface 2A on the inside of the vehicle to be out of the front glass. By properly deciding the angle theta4 at which the light is diffracted on the hologram 4, the light 12 reflected by the surface 2B of the front glass on the outside of the vehicle is made to deviate from the eye range of the driver.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a vehicle display device that is improved in preventing double copying of display contents.

(Prior Art) Conventionally, as a display device for this type of vehicle, a head-up display device shown in Fig. 4 has been known. The information is structured so that it can be viewed.

In the figure, reference numeral 2 denotes a windshield made of a half mirror or the like, and the display content displayed on the image display 1 is reflected by the windshield 2 and reaches 13 of the driver's cab.

Incidentally, in this case, there are two types of light that reach the driver's 13: light 11 that is reflected from the inside surface 2A of the windshield 2 and light 12 that is reflected from the outside surface 2B of the windshield 2.

In this case, the light 11 reflected by the interior surface 2A of the windshield 2 enters point A3 at an incident angle θ, and is reflected in the direction of the driver's eyes 3, resulting in an image 21 seen by the driver's eyes 3. is an extension of the reflected light 11, and was imaged at the P position of eel.

On the other hand, the light 12 reflected from the outside surface 2B of the windshield 2 is incident at point A2 on the inside surface 2A at an incident angle θ2 (where θ is θ2), and is reflected at point B on the outside surface 2B. Then, it was bent at point A3 on the inside surface 2A of the car and reached the driver, 13.

Therefore, in this case, the image 22 seen by driver u3 is an extension of the reflected light 12! It was imaged at the Q position above 2.

(Problem to be Solved by the Invention) However, in the conventional device as described in "-", the driver's eyes 3 see the light 11 reflected on the inside surface 2A of the windshield 2 and the outside surface 2B of the windshield 2. The images 21 and 22 seen by the driver 13 are different straight lines 1.
．． +, i! , are imaged at the upper P and Q positions, so there is a problem that the displayed image becomes a double image for the driver's eyes 3.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to provide a display device for a vehicle in which a displayed image does not appear double to the driver's eyes.

(Means for Solving the Problems) In order to achieve the above-mentioned problems, the present invention reflects the display contents of an image display installed in the vehicle on the windshield, and the driver uses the reflected light to display the image display. In a vehicle display device that visually confirms display contents, a hologram that diffracts light at a predetermined incident angle at a predetermined diffraction angle is provided in the windshield, and the diffraction angle is set so that the diffracted light is reflected from the inside of the windshield to the vehicle. It is characterized by being set so that the direction of the incident light deviates from the driver's eye range when it enters the room.

(Function) In this invention, a hologram that diffracts light at a predetermined incident angle at a predetermined diffraction angle is provided in the windshield, and the diffraction angle is determined when the diffracted light enters the vehicle interior from inside the windshield. Since the direction of the incident light is set to deviate from the driver's eye range, only the light reflected from the inside surface of the windshield reaches the driver's eyes, thereby preventing double copying of the display contents.

(Explanation of Examples) The present invention will be explained below based on the drawings.

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

By the way, this embodiment differs from the conventional example shown in FIG. 4 in that a transmission hologram 4 is provided within the windshield 2, and the other configurations are exactly the same as the above-mentioned conventional example.

Therefore, the same components are given the same reference numerals and the description thereof will be omitted.

As is well known, the transmission hologram 4 has a coherence beam from the same side as the hologram surface!・Created by recording interference fringes of laser light. angle of diffracted light,
The wavelength is determined by the angular interval of the recorded interference fringes.

The following is the configuration of this embodiment, and the operation will be explained next.

First, out of the display light emitted from the image display 1, the light 11 reflected by the vehicle inner surface 2A of the windshield 2 is incident on the point A at an incident angle θ1, as in the conventional example, and is directed toward the driver's mouth 3. An image 21 is formed at a point P on the extension line it of the reflected light 11.

On the other hand, the light 12 reflected on the outside surface 2B of the windshield 2, which caused double copying in the conventional example, is incident on point A2 on the inside surface 2A of the car at an incident angle θ2 slightly smaller than 0 tatami. and enters the windshield at a refraction angle θ3. Then, this incident light 12 enters the zero point of the transmission hologram 4, is diffracted at a diffraction angle θ4, is reflected on the vehicle outer surface 2B, and is further reflected at a refraction angle θ from A3 on the vehicle inner surface 2A.

It is refracted and exits the windshield. In this case, an image 22 is formed at a Q position on the extension line 12 of the reflected light 12.

By the way, in order to prevent the displayed image from looking like a double copy when viewed from the driver's 03, it is necessary to
Preferably, only the light 11 reflected by A enters the driver's eye range 03, and the light 12 reflected by the vehicle outer surface 2B is diverted from the driver's eye range 3.

Therefore, in this embodiment, the angle θ for diffraction by the hologram 4 is appropriately determined so that the light 12 reflected by the windshield outer surface 2B deviates from the eye range.

That is, as shown in FIG. 2(a), the eye range ER has an elliptical shape centered on the driver's 13, and the length of the long sleeve of the ellipse is E I + the length of the short axis is E2.

Here, the thickness of the glass is about 5++ m, and the critical angle θc
Even at -41.5°, it is at most 9u, so AI +
Ignoring the distance between A3, as shown in Figure 2(b),
If the distance between I (-A3) and the driver's center 13, which is the center of eye range ER, is shifted by L, the range of eye range ER seen from point A1 is the central angle φ-2La with point A as the center.
Low' (E2/2L) range.

Therefore, it is reflected from the vehicle outer surface 2B to point A3 (=A+)
In order for the light 12 refracted by 1 to deviate from the range of the eye range ER, the hologram 4 should be manufactured so as to satisfy the following equation.

θ5−θ1〉φ/2 (1) On the other hand,
If the refractive index of the windshield 2 is n, then the following equation can be obtained from Snell's law.

sl ro θ2/sl ro θ3 -5in θ5. /s
ln θ4=n(2) Therefore, for example, θ1-60°, L=800ms.

If E2 = 120u+, n-1, 51, θ2÷60°, then θ5-θ, -φ/2 is 36°6°, so the hologram should be adjusted so that θ4>36.6°. 4
It would be a good idea to create one.

In this embodiment, as described in 1., a transmission hologram 4 is formed in the windshield 2, and light 12 that enters the fluorocarbon 1-glass 2 and is reflected by the windshield outer surface 2B.
I made it possible to remove the eye range ER of the driver's car, so
Eye 3 of the driver's car is Freon!・Recognize only the image 21 formed by the light 11 reflected on the inner surface 2A of the glass car,
Unlike conventional methods, double images do not occur.

Next, a second embodiment of the present invention will be described based on FIG.

Note that the same components as those used in the first embodiment will be described with the same reference numerals.

By the way, when the incident angle θ4 of the light 12 entering the windshield 2 on the windshield outer surface 2B is larger than the critical angle θc (=sln ”(1/n)) of the windshield 2, as shown in FIG. As shown in FIG. 2, the light 12 is repeatedly reflected on both surfaces 2A and 2B of the windshield 2 and does not exit the windshield.

Therefore, in this embodiment, the hologram 4 is manufactured so that the diffraction angle θ of the light transmitted through the hologram 4 is larger than the critical angle θC of the windshield to prevent double images.

In the second embodiment, as shown in ``-'', the light 12 incident on the windshield 2 is incident on the windshield exterior surface 2B at an incident angle larger than the critical angle θC of the windshield, so that the light 12 is transmitted only within the windshield. By repeating reflection, double copying can be prevented as in the first embodiment. Note that in the second embodiment, the display light 12 may pass through the hologram 4 between the BAJs, but since the diffraction angle conditions are not met, most of the display light 12 passes through.

(Effects of the Invention) As described above, the vehicle display device according to the present invention is provided with a hologram in the windshield that diffracts light at a predetermined incident angle at a predetermined diffraction angle, and the diffraction angle is set at a predetermined diffraction angle. When light enters the cabin from inside the windshield, it is set so that the direction of incidence deviates from the driver's eye range, so the only light that reaches the driver's eyes is the light reflected from the inside surface of the windshield. This has the effect that the displayed image is not duplicated as in the conventional case, and a highly clear image can be obtained.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the first embodiment to which the present invention is applied, FIG. 2 is an explanatory diagram of the operation of the first embodiment, FIG. 3 is a cross-sectional view of the second embodiment, and FIG. FIG. 2 is a sectional view of a conventional vehicle display device. 1... Image display 2... Windshield 2A... Windshield inner surface 2B... Windshield outer surface 3... Driver's eyes 4... Hologram ER... Eye range Figure 2 (0) (b) Figure 3 47-

Claims (1)

[Claims] 1. In a vehicle display device in which the display contents of an image display installed in the vehicle are reflected on the windshield, and the driver visually recognizes the display contents of the image display by the reflected light, A hologram that diffracts light at a predetermined incident angle at a predetermined diffraction angle is installed in the windshield, and the diffraction angle is such that when the diffracted light enters the vehicle interior from the windshield, the direction of the incident direction is determined by the driver's eye. A vehicle display device characterized in that it is set to deviate from a range.