JPH08197980A - Holographic display system - Google Patents

Abstract

PURPOSE: To reduce strain in an observable range of an observer by arranging a position where the light which is emitted from an image information injecting means and is made incident on a hologram is emitted toward the hologram in the center of a display image, so as to be movable in a circular arc shape on an almost spherical surface with the almost center of the hologram as the center. CONSTITUTION: An image information injecting means 12 is arranged under windshield glass of a vehicle, and a reflection type hologram 1 is arranged on the windshield glass. The light 5 from the image information injecting means 12 is irradiated to and diffracted by the hologram 1, and is visually confirmed as a virtual image 3 in an observing position of an observer 6. In this case, the image information injecting means 12 is arranged so as to be movable in a circular arc shape on an almost spherical surface 4 with the almost center of the hologram 1 as the center. Therefore, the image information injecting means 12 is moved to a position where a driver can observe the display virtual image 3 according to a difference in a physical build and a posture of the driver, and strain is reduced in an observable range of the observer, and a high-quality display virtual image is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a holographic display system such as a vehicle holographic head-up display system for displaying information necessary for a driver such as speed.

[0002]

2. Description of the Related Art A head-up display (hereinafter referred to as HUD) is used as a method of displaying information to a driver in a vehicle.
Has been used recently. This is because the optical information projected from the image information emitting means such as a liquid crystal display device is displayed on a combiner including a half mirror and a hologram provided on the windshield so that the driver can almost move his or her line of sight from the driving state. It is designed so that the information can be read without it.

In particular, a hologram using a hologram as a combiner is capable of diffracting optical information toward a driver and forming an image at an arbitrary position, and it has a high brightness without impairing the foreground brightness. It is effective as a combiner of HUD because it has a characteristic that a display virtual image can be obtained.

FIG. 4 shows an example of a conventional HUD. This is because the image information emitting means 12 is provided below the windshield of the vehicle, and the light 5 emitted from the image information emitting means 12 is diffracted by the hologram 1 to the reflection hologram 1 provided on the windshield. The virtual image 3 is visually recognized at the observation position of the observer 6.

In order to mount the system on a vehicle, it is essential to reduce the size of the system itself. This requires a system with high optical power. Further, the observable range (eye range) (9 in the figure) needs to be designed to have a certain size depending on the difference in the physique and posture of the driver. When the size of the opening 8 cannot be made sufficiently large as shown in FIG. 4, there is a problem that the observable range 9 is limited to a small size.

As a method for ensuring a small size and a sufficient eye range, as shown in FIG. 3, when the light emitted from the image information emitting means 12 is reflected by the mirror 10 or the like, the mirror is moved around a certain axis in the mirror. There is a method of adding a rotating mechanism. According to this method, the image information emitting means 12 is configured to be substantially 21,21 ', 2.
It was possible to move it to 1 ″, and a method was adopted to secure a sufficient observable range 9 for the observer 6 even with a limited opening (8).

In this mirror rotation method, as in the case of utilizing regular reflection of glass as a combiner provided in the windshield, the combiner itself does not have a magnification for enlarging a display virtual image, or causes a problem when the magnification is small. However, when the magnification is large, there is a problem that the display virtual image is distorted depending on the observation position, and it is difficult to use in a system using a high-magnification hologram combiner. That is, since the region where the hologram receives the light changes, the distortion of the display virtual image is remarkably generated especially when the light is diffracted by the peripheral portion of the hologram.

Such a change in the distortion of the virtual image observed during driving significantly deteriorates the visibility of the display, making it difficult to read the display and causing a serious safety problem.

As described above, conventionally, it has not been possible to realize a system that is small in size, sufficiently secures an eye range, and has less distortion of a display virtual image.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks of the prior art, and it is a simple and small optical system and can be observed by an observer. Another object of the present invention is to newly provide a holographic display system which has not been known so far, which can reduce the distortion within the inside and can realize a sufficiently large observable range.

[0011]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an image information emitting means for generating a light containing information and a diffracting said light toward an observer. In a holographic display system, which is provided with at least a hologram arranged, and which allows a viewer to visually recognize a display virtual image formed by the hologram,
The position of the light emitted from the image information emitting means and incident on the hologram toward the hologram at the center of the display image is movable in an arc shape on a substantially spherical surface centered on the approximate center of the hologram. The present invention provides a characteristic holographic display system.

The present invention will be described in detail below with reference to the drawings.

Here, a case where the holographic display system of the present invention is mounted on a vehicle will be described. FIG.
FIG. 3 is a conceptual diagram in which the holographic display system of the present invention is mounted on a vehicle, and an image information emitting means 12 is provided below the windshield of the vehicle. The windshield of the vehicle body is provided with the reflection hologram 1, and the hologram 1 is irradiated with the above-mentioned light and diffracted, and the virtual image 3 is visually recognized at the observation position of the observer 6.

The light 5 from the image information emitting means 12 is incident on the hologram 1 from the center of the image information emitting means 12 to the center of the hologram 1 at an incident angle of θ _2, which is diffracted from the hologram 1 by the observer 6. The angle of diffraction of the display virtual image 3 to be visually recognized from the center of the hologram 1 is θ ₁ .

In this example, the image information display means 12 is movable in an arc shape on the substantially spherical surface 4 centered on the substantially center of the hologram 1. Thus, the image information display means 1
When 2 itself moves around the hologram 1, the center of the display image emitted from there toward the hologram 1 is 2, 2 ', 2 "in the drawing with the hologram 1 as the center.
It becomes possible to move to the position.

It is necessary to design the observable range 9 to have a certain size depending on the difference in the physique and posture of the driver. However, the opening 8 could not be made sufficiently large due to a space limitation for mounting on a vehicle. Therefore, according to the present invention, the image information display means 12 can be moved as described above so that the diffracted light reaches the necessary observable range 9 through the small opening 8. In this way, a high-quality display virtual image is obtained by moving the image information display means 12 to a position where the driver can observe the display virtual image 3 according to the difference in the physique and posture of the driver.

As described above, the mirror rotation method shown in FIG. 3 has been conventionally proposed to secure the above space. However, in this method, by rotating the mirror 10, the positions at which the display image is emitted are substantially moved around the mirror 10 as the center of rotation, as indicated by 21, 21 ′ and 21 ″ in the figure. Therefore, not only the incident angle of the light entering the hologram combiner changes, but also the region where the hologram receives the light changes, and when the mirror is rotated, a portion having a large aberration at the end of the hologram combiner is used. When a hologram combiner having a high magnification of 2 times or more is used, the aberration becomes very large and the display virtual image is largely deformed.

On the other hand, the movement of the display image in the present invention is performed with the center of the hologram combiner as the center of rotation, so that only the angle of incidence of light on the hologram combiner can be changed, and the hologram area used for diffraction is almost the same. It remains the same, so there is less aberration.

The display image in the present invention is formed by the light emitted from the image information emitting means.
For example, when an optical member such as a mirror is not interposed between the image information emitting unit and the hologram, the display image refers to light including information formed on the surface from which the image information emitting unit emits light. In addition, when the light emitted from the image information emitting means is applied to the hologram through an optical member such as a mirror,
The display image refers to a virtual image formed by this optical member on an extension line from the hologram of the optical axis of light entering the hologram through the optical member.

As a method of moving the position where the display image is emitted according to the present invention, the image information emitting means itself may be moved, or the position where the display image is emitted may be moved substantially by using a mirror or the like. . As a method using a mirror in this case, the mirror is moved and rotated instead of using a certain axis in the mirror as the center of rotation as in the prior art (FIG. 3). As an example of this movement and rotation, there is a method of moving the mirror 10 to 10 ′, 10 ″ so as to be in contact with the ellipsoidal surface 41, with both the hologram center and the image information emitting means 12 center as shown in FIG. 2, the same symbols as those in FIG. 1 indicate the same components as those in FIG.

As described above, by moving and rotating the mirror, it is possible to move the position where the display image is emitted without moving the image information emitting means itself, which is preferable because the driving portion can be made smaller and lighter. .

In addition to the rotating mirror, an optical member such as a prism or hologram may be used as long as it is a reflecting member having an effect of reflecting light. Further, as a method of substantially moving the display member, a transmissive optical member having a refraction effect, a diffraction effect, or the like can be used.

The image information emitting means in the present invention emits light containing information. For example, a so-called light-receiving display element such as a liquid crystal display element, a hot cathode ray tube, a cold cathode ray tube,
It irradiates light emitted from a light source such as a fluorescent display tube, a halogen lamp, a light emitting diode, and a semiconductor laser. Further, it may have both of these functions. Alternatively, the light source itself may be patterned and arranged to generate specific information as light without using the light receiving display element.

In these cases, when the light emitted from the image information emitting means is directed to the hologram, the light is emitted directly from the image information emitting means toward the hologram, or between the image information emitting means and the hologram. Light may travel toward a hologram via various optical members such as a reflecting member such as a mirror, a diffraction member such as a prism, and a transmitting member.

In any case, in the present invention, the position where the display image of the light incident on the hologram is emitted is
It may be moved substantially on a substantially spherical surface centered on the center of the hologram. Therefore, as a means for realizing this, as described above, the image information emitting means itself is moved on an arc of a substantially spherical surface centered on the hologram center, or when the image information emitting means is fixed, the image information emitting means is emitted. Examples include moving an optical member interposed between the means and the hologram. Moreover, even if the optical member is fixed,
By moving the image information emitting means based on an appropriate optical design, the position where the display image of the light incident on the hologram is emitted can be substantially moved on a substantially spherical surface centered on the center of the hologram. And further,
Even by appropriately moving the optical member and the image information emitting means in conjunction with each other, the position at which the display image of the light incident on the hologram is emitted is substantially on a substantially spherical surface centered on the hologram center. It can be moved.

[0026]

Embodiments of the present invention will be described below. In this embodiment, the incident angle to the hologram photosensitive material is 60 °, 3
A reflection hologram is created and used by diverging light from a light source having a focus of 0 °, but the hologram in the present invention is not limited to this angle.

In this embodiment, the distance L2 between the hologram and the image information emitting means is 250 mm and the incident angle θ on the hologram is θ.
₂ = 30 °, and the distance L1 between the hologram and the display virtual image
= 1000 mm and the diffraction angle was fixed at 60 °. But,
The optical arrangement at the time of exposure and the arrangement at the time of configuring the system are not necessarily the same.

A rectangle of about 20 mm × 10 mm was used as the shape of the display image of the light from the image information emitting means. The strongest direction of the light emission intensity distribution of the light source of the image information emitting means is set to be parallel to the optical axis. The observer observed the display virtual image at a position of 850 mm from the hologram combiner and at a position of θ ₁ = 60 ° (observation position design center position).

As a result of observing by changing the observation position design center (6) to the positions of 30 mm in the vertical direction and 85 mm in the horizontal direction, the distortion of the display virtual image was at a level where there was almost no problem.

The observation position is 65 mm below the design center.
When moving to (6 ′ in FIG. 1) for observation, the image information emitting means was moved to 2 ′ in FIG. 1 with the center of the hologram combiner as the center of rotation. At this time, the observer observed the display image at the 3'position. The incident angle θ _{2 of the} light emitted from the display image toward the hologram combiner was set to about 26.5 °.

As a result of observing by changing the observing position to a position of 30 mm vertically and 85 mm horizontally with the 6'point as the center,
The distortion of the display virtual image and the expansion / contraction of the display virtual image were equivalent to the case where the observation point was the design center point, and were at a level that did not pose a problem.

The observation position is 55 mm above the design center 6.
When moving to (6 "in FIG. 1) for observation, the image information emitting means was moved to the 2" point in FIG. 1 with the center of the hologram combiner as the center of rotation. At this time, the observer observed the display image at the position of 3 ″, and the incident angle θ _{2 of the} light emitted from the display image toward the hologram combiner was about 32.5 °.

Centered on the observation position 6 ", 30 above and below
As a result of observing by changing to the position of 85 mm and 85 mm to the left and right, the distortion of the display virtual image and the expansion / contraction of the display virtual image were at the same level as when the observation center was set as the design center point, and were at a level that did not pose a problem.

[0034]

According to the present invention, in a compact system, the display can move the image around the hologram in order to sufficiently secure the eye range of the observer. The region can be always near the center of the hologram, and the distortion or the like generated in the display virtual image observed by the observer can be reduced.

Thus, the magnification of the display virtual image with respect to the display image is increased, and the system is small,
A sufficient eye range can be secured and a high quality image display system can be obtained.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing an example of a holographic display system according to the present invention.

FIG. 2 is a conceptual diagram showing another example of the holographic display system according to the present invention.

FIG. 3 is a conceptual diagram showing an example of a conventional holographic display system.

FIG. 4 is a conceptual diagram showing an example of a conventional HUD.

[Explanation of symbols]

 1: Hologram 2, 2 ', 2 ": Display image 3, 3', 3": Display virtual image 4: Normal direction of display image 6, 6 ', 6 ": Observer 7: Connecting observer and display virtual image Line of sight 8: Opening 9: Visible range (eye range) 10, 10, 10 ″: Reflecting mirror (position of display image) 12: Image information emitting means

Claims (3)

[Claims] 1. An image information emitting means for generating light containing information and a hologram arranged so as to diffract the light toward an observer, and a display virtual image formed by the hologram is observed by the observer. In the holographic display system that is visible to the user, the position of the light emitted from the image information emitting means and incident on the hologram toward the hologram at the center of the display image is approximately the center of the hologram. A holographic display system characterized by being movable in an arc on a spherical surface. 2. The image information emitting means is movable along an arc on the spherical surface, and emits the display image from a position on the spherical surface toward a hologram. Holographic display system. 3. A reflection member, which reflects the light emitted from the image information emitting means toward a hologram as a display image, arranges the hologram center and the image information emitting means center between the image information emitting means and the hologram. The holographic display system according to claim 1, wherein the holographic display system is provided so as to be movable along an elliptic arc as a focal point.