JPH06242395A - Display device attached to head - Google Patents

Abstract

PURPOSE:To obtain a display device attached to the head by which a high- resolution video can be always observed in the center of visual field and whose angle of view is wide. CONSTITUTION:This display device attached to the head is provided with a picture display element 1 and optical systems 2 to 8 projecting the video from the display element 1 to the eye 9 of an observer; and it has a line-of-sight detection means 10 detecting the change of the line of sight of the observer and a displacing means displacing at least one part 2 of the optical system in order to change image-formation characteristic in the line-of-sight direction of the observer detected by the means 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a head-mounted display device, and more particularly to a device capable of viewing a good image in any viewing direction in a wide-field display device.

[0002]

2. Description of the Related Art In recent years, a helmet-type or goggle-type head-mounted display device has been developed for virtual reality or for the purpose of being able to enjoy a large-screen image alone.

Conventionally, for example, as a goggle-type head-mounted display device, as shown in FIG. 5, liquid crystal display elements 1a and 1b having a light source for illumination and optical systems 2a and 2b for projecting their images on an eyeball are shown. It is known that, by providing a display device, a small display device can view an image with a wide angle of view.

A method of detecting a change in the line of sight of an observer and increasing the resolution of the projected image in the central part of the visual field more than other parts to reduce the amount of information, though not a head-mounted display device, is also disclosed. No. 1-252993.

[0005]

However, in a wide-angle head-mounted display device as shown in FIG. 5, for example, aberration is favorably corrected over the entire field of view,
In order to be able to observe a good image on any part of a wide-angle screen, the optical system must be made large and complicated, which is not impossible but not easy.

The present invention has been made in view of the above problems, and an object thereof is to provide a head-mounted display device having a wide angle of view, which enables always observing a high resolution image in the center of a visual field. It is to be.

[0007]

A head-mounted display device of the present invention that achieves the above object comprises an image display element,
In a head-mounted display device including an optical system that projects an image from the image display element onto an eyeball of an observer, a line-of-sight detecting unit that detects a change in the line of sight of the observer, and the line-of-sight detecting unit detects the line of sight. In addition, in order to change the image forming characteristic in the direction of the line of sight of the observer, there is provided a displacing means for displacing at least a part of the optical system.

[0008]

In the present invention, in order to change the line-of-sight detecting means for detecting a change in the line-of-sight of the observer and the image-forming characteristics in the line-of-sight direction of the observer detected by the line-of-sight detecting means,
Since it has a displacing means for displacing at least a part of the optical system, the image at the gazing point can always be clearly seen even if the line of sight moves, and the image at a position apart from the gazing point can be roughly recognized, and the aberration is partially Even with an optical system that has only been corrected, it is possible to observe naturally with a wide angle of view.

[0009]

Embodiments of the head-mounted display device according to the present invention will be described below. The principle of the present invention is that if the resolution of an image at the central portion of the visual field (gazing point) is always high, the Since good and natural images can be observed even when the resolution of the image is low, it is possible to achieve a wider angle of view by constantly improving the imaging characteristics in the line-of-sight direction.
A wide-angle head-mounted display device is provided with an observer's line-of-sight detection means, and a part of the optical system is displaced based on the detection signal so that the aberration at the gazing point of the screen becomes good. , Therefore, even if the line of sight moves, the image at the gazing point can always be clearly seen, and the image at a position apart from the gazing point can be roughly recognized, so an optical system in which the aberration is only partially corrected is used. It is also possible to observe naturally with a wide angle of view.

Referring to FIG. 1, a head mounted display device according to an embodiment of the present invention will be described. Figure 1
FIG. 2 is a cross-sectional view showing only an optical system on the right side of the apparatus of this embodiment, in which 1 is an image display device such as a liquid crystal display device (LCD), 2 is an afocal optical system, 3 is a conjugate plane of LCD 1,
4 is a collimator lens, 5 is a beam splitter, 6 is the locus of the conjugate point of the macula of the retina associated with the rotation of the eyeball 9 of the observer, 7 is a lens, 8 is a concave mirror, 10 is an image sensor such as CCD, and the image on the LCD 1 is , Is relayed to the conjugate plane 3 by the afocal optical system 2, and is further projected onto the retina of the eyeball 9 through the optical system including the collimator lens 4, the beam splitter 5, the lens 7, and the concave mirror 8.

By the way, with such an optical system, the eyeball 9
If the angle of view of the image projected on is wide, it is not easy to obtain a good image over the entire image.
Although the conjugate point of the macula of the retina is determined by the eyeball 9, the concave mirror 8, and the lens 7, a locus like 6 is drawn with the rotation of the eyeball 9. At this time, the aberration in the image formation between the retina and its conjugate surface is corrected by the concave mirror 8 and the lens 7, but the locus 6 of the conjugate point of the macula of the retina becomes a complicated curved surface. However, since the observer is gazing at one point in the trajectory 6, L
By overlapping the conjugate positions of CD1, the observer can observe a good image at the gazing point. To further explain this point, for example, when the locus 6 is as shown in FIG. 2, the image center on the locus 6 is 15, the end of the image is 16, and the gazing point moves from 11 to 12, By moving the conjugate plane of the LCD 1 from 13 to 14, it is possible to continue observing an image with high resolution. Similarly, when the gazing point is moved to the image center 15 and the edge 16 of the image, by moving the conjugate plane of the LCD 1 to 17 and 18, similarly, a good image can be continuously observed.

Therefore, the light traveling from the surface of the eyeball 9 through the concave mirror 8 and the lens 7 in the opposite direction is branched by the beam splitter 5, and the image pickup device 10 is located at a position conjugate with the surface of the eyeball 9.
Are arranged so that the line of sight of the eyeball 9, that is, the movement of the gazing point is detected. Based on the detection information, the afocal optical system 2 is moved in the optical axis direction by a predetermined distance (determined based on the locus 6) to match the conjugate position of the LCD 1 with the gazing point of the locus 6. At this time, due to the movement of the afocal optical system 2, the conjugate plane 3 of the afocal optical system 2 of the LCD 1 moves in the optical axis direction, but its magnification does not change.

The afocal optical system is schematically shown in FIG. 3. The afocal optical system is represented by two thin lenses, and the focal length of the front lens is f and the focal length of the rear lens is f '. , L ₁ is the object point position from the front lens, L ₂ is the image point position from the rear lens, and β (defined as β = f ′ / f) is the magnification of this afocal optical system. _Since there is a relation of ₂ = β (1 + β) f + β ² L ₁ , dL ₂ = β ² dL ₁ . The movement amount Δ of the conjugate surface when the afocal optical system is moved is Δ = dL ₂ −dL ₁ = β ² dL ₁ −dL ₁ = (β ² −
1) It becomes dL ₁ . Therefore, when β = ± 1, Δ = 0 always holds, so that the magnification β of the afocal optical system 2 must be β ≠ ± 1.

In this way, it is preferable to move the afocal optical system 2 in association with the movement of the line of sight of the eyeball 9 so that the conjugate plane of the image plane 3 thereof always coincides with the gazing point of the locus 6. The point at which a good image is obtained moves on the locus 6, but the size of the image does not change. In other words, the observer can observe the image at the point where he or she is always gazing well, and due to the characteristics of the eye, the peripheral image with low resolving power does not bother even if some aberration occurs and the movement of the line of sight With this, the image does not change and a natural image can be observed with a wide angle of view.

Next, a modification of the above embodiment will be described with reference to FIG. In the above-described embodiment, the lens group 2 is displaced, but in this embodiment, the LCD 1 arranged at the position corresponding to the conjugate plane 3 in FIG. 1 is displaced in the optical axis direction. Even with such a configuration, the same operation as that of the previous embodiment can be obtained. With such an arrangement, a compact structure can be obtained.

The head-mounted display device of the present invention has been described above based on the embodiments, but the present invention is not limited to these embodiments and various modifications can be made.

[0017]

As is apparent from the above description, according to the head-mounted display device of the present invention, the line-of-sight detection means for detecting changes in the line-of-sight of the observer, and the line-of-sight of the observer detected by the line-of-sight detection means. In order to change the image forming characteristic in the direction, since it has a displacing means for displacing at least a part of the optical system, the image at the gazing point is always clearly visible even if the line of sight moves, and the distant from the gazing point. A position image can be roughly recognized, and even if an optical system in which aberrations are only partially corrected is used, natural observation can be performed at a wide angle of view.

[Brief description of drawings]

FIG. 1 is a sectional view showing only an optical system on the right side of a head-mounted display device according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining the operation of the present invention.

FIG. 3 is a diagram schematically showing an afocal optical system.

FIG. 4 is a view similar to FIG. 1 of another embodiment.

FIG. 5 is a cross-sectional view of one conventional head-mounted display device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Image display element (LCD) 2 ... Afocal optical system 3 ... LCD conjugate plane 4 ... Collimator lens 5 ... Beam splitter 6 ... Locus of retinal macula conjugate point 7 ... Lens 8 ... Concave mirror 9 ... Eyeball 10 ... Imaging element

Claims (1)

[Claims] 1. A head-mounted display device comprising an image display element and an optical system for projecting an image from the image display element onto an eyeball of an observer, and a line-of-sight detection for detecting a change in the line of sight of the observer. And a displacement means for displacing at least a part of the optical system in order to change the image forming characteristics in the visual line direction of the observer detected by the visual line detection means. Display device.