JPH04303813A - Headup display - Google Patents

Abstract

PURPOSE:To display a sharp image without blur due to aberration (especially, at a peripheral part) in a volume phase reflection type headup display. CONSTITUTION:The center part of a combiner is formed with a holographic optical device 2b on which (variable) dashboard information 4 is displayed, and the peripheral part is formed with display holograms 2a, 2c in which the dashboard information 4 (such as an alarm lamp flashing temporarily) is pattern- manufactured. An image display means 3 which illuminates the dashboard information on the combiner 2 as display light is comprised in the two-dimensional arrangement of a point light source from which light of narrow band area can be emitted, and variable information can be displayed and emitted from the center part, and the point light sources in accordance with the display holograms 2a, 2c are flashed at the peripheral part. Thereby, it is possible to prevent the blur of the image due to the influence of the aberration and to display the sharp image.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a head-up display using a hologram, and more particularly to a head-up display capable of displaying clear images. A head-up display can be installed in aircraft, fighter jets, automobiles, ships, trains, etc. as a device to reduce the burden on drivers.

0002

[Prior Art] Conventionally, in a head-up display using a hologram, as disclosed in Japanese Patent Application Laid-Open No. 61-278820, a holographic combiner that displays external scenery and instrument panel information in a superimposed manner has a volumetric It was a phase reflection type holographic optical element. Further, the instrument panel information is displayed as an image on a display means such as a CRT or a liquid crystal display device, and the driver observes a virtual image obtained by reflecting and diffracting the image on the display means by a holographic optical element.

0003

However, in the head-up display as described above, information from the peripheral portion of the display means is distorted due to aberrations, making it impossible to display clearly. It has also been considered to correct this aberration by combining glass lenses, but this would make the entire device heavy and large, making it impractical. The present invention has been made for the purpose of eliminating the above-mentioned drawbacks of the prior art, that is, distortion of displayed images due to aberrations, and enabling clear display.

0004

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a device for displaying instrument panel information using a CRT.
Instead of a liquid crystal display or a liquid crystal display, it is a collection of point light sources that are two-dimensionally arranged LEDs and visible light semiconductor lasers.

[0005] In the central part of the display device, which has relatively few aberrations, instrument panel information is displayed as an image as in the past, and the combiner reflects and diffracts this image light to allow the driver to read the information. The central part of this display device displays information that changes from moment to moment.

On the other hand, marks that are temporarily displayed in the instrument panel information, such as warning lights, are volumes that are created so that the corresponding marks are reproduced with light emitted from a point light source on the periphery of the display device. It is a phase reflection type display hologram.

[0007]

[Operation] As described above, in the present invention, the combiner in the head-up display combines a holographic optical element portion and a point light source that acts to reflect only a narrow band of light and transmit light of other wavelengths. It consists of a display hologram part that reproduces images using spherical waves emitted from the hologram.

The holographic optical element is fabricated at the center of the combiner and displays information clearly from the display device with relatively little aberration. In addition, the display hologram part is fabricated on the periphery of the combiner, and since the image previously taken as a hologram is reproduced using spherical waves, it is also possible to display a clear image. In addition, since the information source of the instrument panel is a two-dimensional array of point light sources such as LEDs and semiconductor lasers, the efficiency of light usage is high and high brightness display is possible.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a head-up display of the present invention will be explained based on the drawings. FIG. 1 is a schematic diagram showing an example of the overall configuration of a head-up display according to the present invention.

Information light 4 emitted from the image display means 3 illuminates the holographic combiner 2, and reflected and diffracted light 5
reaches the eyes of pilot 7. This holographic combiner 2 consists of a holographic optical element part 2b and display hologram parts 2a, 2c. When the light from the point light source 3a illuminates the hologram 2a, the image shown at 16a in FIG. 4 is displayed, for example, and when the hologram 2c is similarly illuminated by the point light source 3c, the image 16b is displayed. On the other hand, the point light source array 3b displays information that changes from moment to moment, such as speed information, and displays this by reflecting and diffracting it by the holographic optical element 2b.

[0011] Both the holographic optical element part and the display hologram part of this holographic combiner are the same as a hologram that is generally referred to as a Lippmann type hologram, and diffraction is influenced by Bragg conditions, resulting in a mixture of displayed images. doesn't happen.

Next, an example of a method for manufacturing the holographic combiner in this embodiment will be explained. FIG. 2 shows how the holographic optical element in the central part of the holographic combiner 2 is made. Here, the laser beam emitted from the laser oscillator 8 is made into a spherical wave by the lens 10, and is made to enter the hologram photosensitive material 11 from the front and back surfaces to cause interference, thereby photographing a portion of the holographic optical element. At this time, the display hologram portion is covered with a light-shielding mask 12 so as not to be exposed to light.

FIG. 3 shows a method for making the display hologram portion at the peripheral portion of the holographic combiner 2. As shown in FIG. A transparency 16 of the image to be displayed (e.g.
16a and 16b) in FIG. 4 are sandwiched between the holder 13 and the diffuser plate 14, and are illuminated with laser light diverging from the lens 10. The light transmitted through the transparent positive image 16 is diffused by the diffuser plate 14, and this is reflected in the display hologram portion 2.
This corresponds to the object light at the time of photographing a and 2c. On the other hand, the reference light is a spherical wave emitted from one point on the opposite side.

In this manner, interference fringes between the diffused light from the display image 16 and the spherical wave are photographed at the peripheral portion of the hologram photosensitive material 11. At this time, when photographing the image 16a, the point light source is moved to the position 15a, and in 16b, the point light source is moved to the position 15b for exposure, and the other parts are covered with the light shielding mask 12.

[0015]

As explained above, according to the present invention, a holographic combiner in a head-up display has a holographic optical element part and a display hologram part, and an image display means consisting of a collection of point light sources. By providing the same functions as before,
Moreover, it becomes possible to display a clear image.

[0016]

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram showing an example of the overall configuration of a head-up display according to the present invention.

FIG. 2 is an explanatory diagram showing an example of a method for manufacturing a holographic optical element portion of a holographic combiner.

FIG. 3 is an explanatory diagram showing an example of a method for manufacturing a display hologram portion of a holographic combiner.

FIG. 4 is an explanatory diagram showing an example of a display image displayed in a display hologram portion of the holographic combiner.

FIG. 5 is a schematic explanatory diagram showing an example of the overall configuration of a conventional head-up display.

[Explanation of symbols]

1... Ambient light 2... Holographic combiner 3
... Image display means 4 ... Display light (instrument panel information) 6 ...
Regularly reflected light 9...Mirror 10...Lens 11...Photosensitive material 12...Shading mask 16...Transparent positive image 17...Moving stage 18...Half mirror 19...CRT

Claims (1)

[Claims] Claims: 1. Image display means; display light (instrument panel information) emitted from the display means is reflected and diffracted, and the driver is shown both the scenery of the outside world and the display light through the front glass window of the vehicle; In a head-up display equipped with a combiner for visual recognition, a certain part of the combiner attached to the glass window or sandwiched in the glass window is
It is a holographic optical element that reflects only a narrow band of light and transmits light of other wavelengths, and the remaining parts reproduce multiple display images using light from corresponding point light sources. It is a display hologram, and the image display means that emits display light (instrument panel information) is
A head-up display characterized by a two-dimensional array of point light sources that emit light in a narrow band.