JPH01100511A - heads up display device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a heads-up display used in an aircraft or vehicle.
ay) It concerns the device.

[Conventional technology]

2. Description of the Related Art In a vehicle or the like, a head-up display device (hereinafter referred to as an HID device) is used when it is desired to visually check information such as speed without taking one's eyes off the front view while driving. This HUD device superimposes desired image information on external field of view information and makes it visible at the same time.The HUD device uses a lens optical system shown in Fig. 2(a), and a holographic optical system shown in Fig. 2(b). There are two types: one based on the element and the other based on the element.

The lens optical system shown in Fig. 2(a) is CR
Image light from a display 1 having a T (cathode ray tube) or a fluorescent display tube is made parallel through a collimating lens 2, reflected by a total reflection mirror 3, and then further reflected by a half mirror 4. When reflected by the half mirror 4, it is superimposed on the information of the external field of view, and the observer (driver) can visually recognize this information at the same time. In addition, in the case of the holographic optical element (hereinafter referred to as HOE) shown in FIG. 2, the image light from the display 1 is reflected by a total reflection mirror 3 and then diffracted by an HOE 6 provided on a glass substrate 5 to be externalized. It is superimposed on the light from the field of view, and the image light is H
It is collimated when passing through OE6.

In this way, the half mirror type and H
There are HOE-type HUD devices that use OE, and both of these superimpose various image information from display B1 on external visibility information such as the scenery outside the vehicle, as described above. An image such as a character 1 figure displayed on the screen is collimated by the collimating lens 2 or the HOE 6. As a result, the displayed image is focused at a far distance, and the observer's eyes are focused at a far distance, so the observer can see the outside scene and view necessary image information at the same time. .

FIG. 3 is a diagram showing a conventional simplified HUD device for a vehicle. In this HUD device, the image light emitted from the display 1 is simply collimated by the HOE 6, but at this time, the HOE 6 diffracts only the light in a specific wavelength band of the image light.
It provides image information to the observer's eyes. Light of other wavelengths passes through HOE6 and forms glare.
) 7. Howl. That is, since the image light is output from the CRT, fluorescent display tube, etc. of the display device 1, it has a spectrum with a fairly wide wavelength range. For example, a green fluorescent display tube has a spectrum of about 460 to 600 nm, and when this fluorescent display tube and an HOE that diffracts green light are used, the wavelength band of the diffracted light is about 480 to 52 nm.
0 nm, the other light that is not diffracted is HO
It passes through E and becomes glare as described above. This glare also makes it difficult to see the scenery outside the vehicle, impeding safe driving.

At this time, if the green wavelength light diffracted by H and OE is λ6, the other red and blue wavelength lights λ□ and λ8 are )(O
E, which causes the above-mentioned glare, and especially in weather such as rain or fog, they act as a screen and the glare becomes noticeable. Furthermore, although the HOE is formed on a glass substrate, since the refractive index of glass is greater than that of air, a portion of the image light emitted from the display 1 λ9. λ8 is confined inside the glass substrate 5,
Therefore, the entire glass substrate 5 becomes bright, making it even more difficult to see the outside scenery, especially at night.

Also, in a half-mirror type HUD device, as in the case of the IOE type device (mentioned above), a portion of the image light output from the display passes through the half mirror, which creates glare and makes it difficult to see the outside scene. This can interfere with driving and operating a vehicle.

[Problem that the invention seeks to solve]

Since the conventional HUD device is configured as described above,
There is a problem in that a large amount of glare is generated, and the image light is trapped inside the HOE board or half mirror, making it bright, making it difficult to see the outside, and impeding safe driving.

The present invention has been made in view of these problems, and aims to provide a HUD device in which the occurrence of glare is suppressed, the glass substrate does not shine brightly, and the outside scenery can be easily seen.

Means for Solving Problem C) The HUD device of the present invention has two reflective HOE substrates facing each other that diffract only image light in the same wavelength band,
The image light is diffracted by these IOEs and superimposed on the light from the external field of view.

[Effect]

In the HUD device of the present invention, image light is sequentially diffracted by two HOE substrates placed opposite each other, and is superimposed on light from the external field of view. At that time, only the image light in the wavelength band of the first HOE substrate is diffracted, and this image light is
All the light is diffracted by the second HOE substrate. Therefore, the second HOE substrate serving as the display section has no glare, and light is not trapped inside and does not shine brightly.

〔Example〕

FIG. 1 is a schematic configuration diagram of a HUD device according to the present invention. In the figure, reference numeral 1 denotes a display for outputting image light, and reference numerals 8a and 8b denote two reflective HOE substrates that diffract only image light in the same wavelength band, which are arranged in parallel and facing each other. This HOE board 8a.

8b is HOEloa on the glass substrates 9a and 9b.

10b, and the image light from the display 1 is diffracted by these (OEloa, 10b) and superimposed on the light from the external view indicated by the dotted line in the figure.

The image light output from the display device 1 includes red, green, and blue wavelength light, and is HOEloa.

10b, both of which diffract only the light λ6 in the green wavelength band, this image light is transmitted to the HOElo of the first substrate 8a.
Only the green light λG is diffracted at point a, and the other glare-causing light λ8. λ8 passes through. Then, the diffracted green image light λ6 is directed toward the second substrate 8b, and its HOE
It is further diffracted by the lob. At this time, since the image light that has reached the second board 8b is in the green wavelength band, it is all diffracted by the second HOElob and superimposed on the light from outside the vehicle to provide image information to the driver. do.

In other words, the second HOE board 8 is in the driver's line of sight.
b, but only the green wavelength light λG from the first HOE board 8a reaches this second HOE board 8b, and this light λ. Since all of the light is diffracted, other wavelengths of light λ8°λ8 that cause glare do not appear in the driver's line of sight. Further, since light is not trapped in the glass substrate 9b forming the second HOE substrate 8b, the second HOE substrate 8b does not shine brightly. Therefore, the scenery outside the vehicle is easy to see even at night, and safe driving is not hindered.

Note that each HOE board 8a, 8b must be arranged so that it does not look unsightly to an observer (driver).

Therefore, the first HOE board 8a is placed below the windshield, for example, under the dash board, so as not to enter the observer's field of view, and the second HOE board 8b is placed so that the display image is outside the windshield. It is desirable to place it in the observer's line of sight so that it appears in the viewer's line of sight.

〔Effect of the invention〕

As explained above, according to the present invention, two HOE substrates that diffract only the image light in the same wavelength band are arranged facing each other, and the image light is diffracted by these HOEs to generate light from the external field of view. Since the light is superimposed on the outside, the occurrence of glare is suppressed, and the glass substrate in the viewer's line of sight does not shine brightly, making it easy to see the outside scenery.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a head-up display device according to the present invention, FIGS. 2(a) and (b) are configuration diagrams showing the principle of a head-up display, and FIG. 3 is a configuration diagram showing a conventional example. 4 are explanatory diagrams showing how light is trapped inside the glass substrate of FIG. 3. 1...Displays 8a, 8b...Reflective holographic optical element substrates 9a, 9b...Glass substrates 10a, 10b...Holographic optical element application People Stanley Electric Co., Ltd. hka

Claims (1)

[Claims] In a head-up display device that allows desired image information to be viewed at the same time as information in the external field of view, two reflective holographic optical element substrates that diffract only image light in the same wavelength band are placed facing each other, and the image light is A head-up display device characterized by diffracting light using these holographic optical elements and superimposing it on light from an external field of view.