JPH02309314A - Head-up display device - Google Patents

Abstract

PURPOSE:To eliminate the blurring of a displayed image caused by the dispersion of wavelength and to miniaturize a device by adjusting the position and the angle of a 1st diffraction grating according to the specified relation of function in the case that a luminous flux from the 1st diffraction grating is reflected and diffracted to be made incident on a 2nd diffraction grating which transmits light. CONSTITUTION:The luminous flux 32 from the surface of a display unit 31 such as a CRT, etc., is reflected and diffracted by the 1st reflection type diffraction grating 11 on the surface of a substrate 10 to become the luminous flux 33, which is made incident on the 2nd reflection volume phase type diffraction grating 35. The luminous flux 36 reflected and diffracted in the 2nd grating 35 is made incident on the pupil 51 of an observer, so that the display on the surface of the display unit 31 is observed with background. Pins 22 and 23 are provided on the substrate 10 of the diffraction grating 11. Then, the pin 22 is fitted in a long groove 21 and the pin 23 is made to slide while being pressed to the cam surface 19 of a guiding plate 20, then the shape of the cam surface is appropriately constituted in function, so that the angle of the diffraction grating 11 is excellently adjusted. Thus, the blurring of the displayed image caused by the dispersion of the wavelength of the diffraction grating is reduced and an observation direction is easily adjusted to various directions. Then, the device is efficiently housed in a small capacity.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a head-up display device, and in particular to a head-up display device, in which image information such as a natural scene, etc., and artificially created The present invention relates to a head-up display device that is suitable for viewing both displayed information at the same time.

(Prior art) Using an optically transparent light beam coupling element such as a multilayer film reflective surface or a hologram optical element, display information from a display device and image information such as external natural scenery can be displayed within the same field of view. A display device that enables spatially superimposed viewing is generally called a head-up display device, and is widely used in various fields.

Conventionally, various display devices have been proposed in which this head-up display device is used in various vehicles, including the cockpit of an aircraft.

When such a head-up display device is used by people of various physiques, it is desired to be able to observe it in better conditions from various positions (directions).

For example, the seat height in the driver's seat of a car when a half mirror or dichroic mirror is used as a beam coupling element,
When adjusting the display optical system in response to changes in seat position, etc., Japanese Utility Model Application Publication No. 61-31931 proposes a method in which the position of a half mirror is adjusted.

Furthermore, Japanese Patent Laid-Open No. 188236/1983 proposes a method in which the angle of a bending mirror disposed in the optical path is adjusted.

Furthermore, Japanese Utility Model Application Publication No. 62-46228 proposes a method in which the entire display optical system is rotated.

(Problems to be Solved by the Invention) When a hologram diffraction grating element is used instead of a half mirror as a light beam coupling element, the outside scenery can be observed brightly, and at the same time, an image of the display element consisting of a light beam with excellent monochromaticity can be observed. Although they have the advantage of reflecting information with high diffraction efficiency and allowing bright observation, each of the above-mentioned methods has various inconveniences when it comes to adjusting the observation position.

Next, the fifth. With reference to FIG. 6, problems that occur when the observation position (observation direction) changes using a reflective volume phase type diffraction grating will be explained as an example.

In Fig. 5, a reflection volume phase type diffraction grating 35 is used, and the reflection diffraction angle θ4=SO (solid line) and the angle 04'=45° (
The image is shown as being observed from the direction indicated by the dashed line.

Unlike a half mirror, the diffraction grating 35 generates a large amount of diffracted light in the diffraction direction that satisfies the Bragg condition, and at the same time, a shift occurs in the center wavelength.

The diffraction grating shown in the figure is mainly composed of poly(N-vinylcarbazole) as a photosensitive material, and has an average refractive index of 1.67, an in-plane grating pitch of 1.92 μm, and a grating inclination angle of 4.94°. be.

Light with a wavelength of 510 nm that enters this diffraction grating 35 at an incident angle θ, = 300 is reflected and diffracted at an angle of reflection θ.
,=so'. Also, the incident angle θ,'=25.9°
The incident light having a wavelength of 518 nm is reflected and diffracted and travels in a direction with a reflection and diffraction angle θi'=45°.

Figure 6 shows a fluorescent display tube (ZnO, Z
This figure shows the spectral energy distribution of a PI3-Gl phosphor whose main composition is rl. By setting the center wavelength of the diffraction grating (the wavelength at which the amount of diffracted light is maximum) near the peak wavelength of the spectral energy distribution of the phosphor, the display object can be observed brightly even if the observation position changes up and down or back and forth. Becomes an easy-to-understand accent.

In a display device having such a configuration, the wavelength width of the light used ranges from 10 nm to 50 nm due to the wavelength characteristics of the diffraction grating 35, and as a result, the displayed image becomes blurred due to wavelength dispersion. As an example of means for correcting such chromatic dispersion, US Pat. No. 4,613,200 proposes a method in which two diffraction gratings, the diffraction grating 35 and a similar diffraction grating, are arranged parallel to each other.

However, although this method can correct aberrations, it requires a long optical path length from the display to the diffraction grating, which poses the problem of increasing the size of the entire device.
This is not very desirable for an office machine placed on a desk or a dash board for the driver's seat of a car, as it is desired that the volume be as small as possible.

The present invention can be efficiently packaged within a small volume;
Moreover, it is an object of the present invention to provide a head-up display device in which the displayed image is less blurred due to the wavelength dispersion of the diffraction grating, and the observation position (observation direction) can be easily adjusted to various positions (directions).

(Means for Solving the Problems) A head-up display device of the present invention includes a display device that displays information with a light beam having a predetermined wavelength width, and a first diffraction grating that diffracts and deflects the light beam from the display device. , a head-up display device comprising a second diffraction grating that reflects and diffracts the light beam from the first diffraction grating and has light transmittance, wherein the position and angle of the first diffraction grating are adjusted to It is characterized by making adjustments according to functional relationships.

(Embodiment) FIG. 1 is a schematic diagram of a main part of an optical system according to an embodiment of the present invention. In the figure, a light beam 32 emitted from the surface of a display device 31 such as a CRT or a fluorescent tube is reflected and diffracted by a reflective first diffraction grating 11 provided on the surface of a substrate 11, and becomes a light beam 33, which is placed on a transparent substrate. The light is incident on the second diffraction grating 35 of the reflective volume phase type, which is disposed between 34° and 37°. The light beam 36 reflected and diffracted by the second diffraction grating 35 enters the viewer @51, and the display on the display 31 is observed together with the background.

In this embodiment, the first diffraction grating 11 is a reflection type diffraction grating, which is a surface relief grating formed by machining, and a relief grating formed on the back surface of a transparent substrate.

A reflective volume phase type diffraction grating or the like can be used. In addition, the grid arrangement can be arranged so that it has a light condensing property like a part of a zone plate or has the function of a cylindrical lens, in addition to the straight line equidistant grid. It is possible to use methods such as pattern printing by a laser, holographic pattern formation by three-beam interference from a laser, etc. In addition to the flat surface, convex, concave, and cylindrical surfaces can also be used for the substrate.

In this embodiment, a sufficient function can be achieved by using a linearly spaced grating, so the following explanation will be based on a case where a linearly spaced evenly spaced grating on a plane is used as the first diffraction grating.

In this embodiment, the grating pitch P1 required for the first diffraction grating 11 is 0.82 μm. The light beam 33 enters the second diffraction grating 35 at an incident angle θ3=25°, and the angle θ4=45°.
It is reflected and diffracted at °. Here, the in-plane pitch P2 of the diffraction grating 35 is 1.91 μm, and the materials constituting the diffraction grating include various materials such as poly(N-vinylcarbazole), dichromate gelatin, and gum arabic. can be used. In the present invention, the configuration is such that blurring due to color dispersion of the displayed display content to be observed is prevented.

Next, we will briefly explain the technical details.

Currently, the display device 31 has a finite width, for example, a half width of 10 nm to 30 nm.
The reflection type diffraction grating 35 has a wavelength characteristic of about 0 nm, and the corresponding reflection type diffraction grating 35 also has a wavelength characteristic of about 10 nm to 1100 nm half width.

The most noticeable deterioration in image quality when observing display content displayed using a combination of such a light source and a diffraction grating is image blurring in the vertical direction of the image.

This vertical blur correction is performed as follows. Now, light with a wavelength much longer than the center wavelength (e.g. 510 nm)
515 nm). A virtual light flux can be calculated by back-ray tracing this wavelength light along the optical path 36. When these virtual light beams are made to intersect with the result of ray tracing of the center wavelength on the display 31, an image in which vertical color shift has been corrected can be observed from the viewing position 51. The conditions for correcting the color shift at this time are that the distance from the display 31 to the first diffraction grating f-11 is 21, the distance from the first diffraction grating 11 to the second diffraction grating 35 is 22, and the distance from the display 31 to the second diffraction grating 35 is 22. The incident angle and diffraction angle of the light beam from
1. θ2, and the incident angle and diffraction angle to the second diffraction grating 35 are 03. Letting θ4, it is given by. Here, the width P1゜P2 of the diffraction grating is pi = λo / l sin θ, -5in θ21P
2=λo/l s inθ3−sinθ41.

As a result, the display 31 is fixed and the first diffraction grating 7-1
1 may be varied such that, for example, the following conditional expression is satisfied.

(a) Reference position incident angle θ, = 45°1 diffraction angle θ2 = 5°, incident angle θ,
= 30', diffraction angle θ4 = 50°, center wavelength 510 nm
, j22/J! 1 = 2 (b) When the observation position moves downward, the incident angle θ, = 41', the diffraction angle θ2 = 1.7°, the incident angle θ
3=25.9°, diffraction angle θ4=45', center wavelength 518
nm, J12/11=1-92(c)1M! When the detection position moves upward, the incident angle θ1 = 490, the diffraction angle θ2 = 8
．． 3', incident angle θ, = 33.9°, diffraction angle θ4; 55°
, center wavelength 502 nm, ff12/J21=2.17
In this embodiment, the movement required for the diffraction grating 11 is approximately parallel movement, so the diffraction grating 11 may be moved using, for example, a normal straight rail guide.

FIG. 2 is an explanatory diagram of an embodiment of the adjusting means for adjusting the optical path length and reflection/diffraction angle by varying the first diffraction grating 11 according to changes in the observation direction in the present invention.

In the figure, a bottle 22 and a bottle 23 are implanted in the substrate 10 of the diffraction grating 11. Of these, the bottle 22 is fitted into a long groove 21 provided in the kite board 20, and has a length t.
It is moving within fI21. On the other hand, the bottle 23 is pressed against the cam surface 19 of the guide plate 20 by a pressing mechanism (not shown) and is slid along the cam surface 19.

Now, Bin 22 is Bin 22. When you move to the position, the bin 23
moves to the position of bin 231. Also, bottle 22 is bottle 22
When the bin 23 moves to the position □, the bin 23 moves to the bin 232 position.

In this embodiment, the rotation angle is set as an arbitrary function of the amount of movement of the diffraction grating 11 by appropriately configuring the shape of the cam surface 19 in a functional form.

In addition, the diffraction grating in the real/ih example! When rotating l by a large angle, a commonly used mirror rotation mechanism may be used.

FIG. 3 is a schematic diagram of another embodiment of the adjusting means for rotating the diffraction grating 11 according to the present invention.

In the figure, a reflective diffraction grating 11 is formed on the surface of a substrate 10. As shown in FIG. A bottle 18 is attached to the other end of the substrate 10 to a support member (not shown), and the substrate 10 is rotated about the bottle 18 as a rotation axis. This makes the diffraction grating 1! position 1
11. Or it has moved to position 11□.

This embodiment has the advantage that the angle of the diffraction grating can be adjusted satisfactorily with high reliability using a simple configuration.

Furthermore, in this embodiment, by moving the dowel 18 vertically away from the diffraction grating 11, the relationship between the optical path length and the rotation angle can be finely adjusted.

FIG. 4 is a schematic diagram of another embodiment of the adjustment means for adjusting the diffraction grating 11 according to the present invention.

In the figure, a reflective diffraction grating 11 is formed on a substrate 10, and is attached to a link component 62.

The members 60, 61, 62, and 63 constitute non-parallel links. When the member 61 moves to the position of the member 611, the member 62 moves to the member 62° position, and the diffraction grating 11 moves to the diffraction grating 11° position. As a result, the diffraction grating 1
1 center position movement and rotation angle adjustment.

(Effects of the Invention) According to the present invention, the light beam from the image information on the display surface is diffracted through two diffraction gratings: a diffraction grating with a predetermined shape and a volume phase type diffraction grating, thereby creating a background scenery and space. When observing both in a superimposed manner, the optical path length and rotation angle are corrected using adjustment means installed in the diffraction grating to compensate for chromatic aberration fluctuations due to changes in the center wavelength that occur when the observer's observation position (observation direction) changes. As a result, it is possible to achieve a head-up display device in which image information on the display surface can be observed in good condition without blurring of the displayed image due to wavelength dispersion.

[Brief explanation of the drawing]

No. 1 is a schematic diagram of the main parts of an optical system according to an embodiment of the present invention, and No. 2. Third. 4 is a schematic diagram of one embodiment of the adjustment means for adjusting the diffraction grating shown in FIG. 1, FIG. 5 is an explanatory diagram showing the diffraction state of the volume phase type diffraction grating, and FIG. 6 is a diagram according to the present invention. FIG. 3 is an explanatory diagram of the spectral energy distribution of the display device. In the figure, 31 is a display, 11 is a first diffraction grating, and 10.3
4 is a substrate, 35 is a second diffraction grating, 35.37 is a transparent substrate, 51 is an observer, and 35 is a volume phase type diffraction grating f. Patent applicant: Canon Corporation Figure 1 Figure 2 Figure 4 Figure 3 Figure 5

Claims (1)

[Claims] (1) A display that displays information with a light beam having a predetermined wavelength width, a first diffraction grating that diffracts and deflects the light beam from the display, a light beam that reflects and diffracts the light beam from the first diffraction grating, and A head-up display device comprising a second diffraction grating having transparency, wherein the position and angle of the first diffraction grating are adjusted according to a predetermined functional relationship.