JPH10268228A - Head-mounted display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a head-mounted display device capable of very effectively utilizing light from an illuminating means. SOLUTION: Illuminating means 3, a reflection type LCD 2b, a reflection type LCD 2a and a lens 6 are arranged being opposite to each other, respectively. Image light beams 10P, 10S transmitted from two LCD's 2a, 2b as reflecting beams by the illuminating means 3 are synthesized by a polarizing beam splitter 4, exerted by the refracting action of the lens 6 and observed by a user as the expanded virtual image.

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 which is mounted on a user's head and allows a user to visually recognize an image formed by image display means as an enlarged virtual image.

[0002]

2. Description of the Related Art A head-mounted display device has been proposed in order to meet the demand for improving the portability of video and data displays. Therefore, miniaturization and low power have been achieved. As one means for realizing both higher resolution, smaller size, and lower power, there is an attempt to use a reflection type liquid crystal display device (reflection type LCD) as a display source. The head mounted display device described in Japanese Patent Application Laid-Open No. 8-320451 is an example of such a device, and a device as shown in FIG. 7 has been proposed. This is roughly composed of an illuminating means 24, a half mirror 25, a reflective LCD 26, and a magnifying concave mirror 27. The image displayed on the reflective LCD 26 is illuminated by illumination light, and the image light reflected as image information there is magnified concave mirror. The light is refracted by 27 and enters the user's eye 28.

[0003]

However, this conventional technique has the following problems. The illuminating light emitted from the illuminating unit 24 reaches the illuminating unit 2 before reaching the user's eye 28.
4 and between the reflective LCD 26, between the reflective LCD 26 and the magnifying concave mirror 27, and between the magnifying concave mirror 27 and the user's eye 28, three times through the half mirror 25 in total.
That is, assuming that the reflectance and transmittance of the half mirror 25 are 50% for simplicity, 87.5% of the illumination light emitted from the illumination means 24 is lost by the half mirror 25. The reflection type LCD 26 has one advantage over the transmission type LCD in that the aperture ratio and contrast are improved by using the electrode portion as a pixel, but this advantage cannot be fully utilized. Further, in such a configuration using the half mirror 25, it is necessary to further provide a polarizing means for detecting the image light somewhere in the optical path.
Light loss there is also useless.

A head-mounted display device according to the present invention has been made to solve the above-mentioned problems, and a main object of the present invention is to realize a head-mounted display device capable of extremely effectively using light from illumination means. It is in.

[0005]

A first aspect of the present invention is a head mounted display device mounted on a user's head,
Two reflective display elements for displaying an image by reflected light,
Image display means comprising: illumination means for illuminating a reflective display element; and polarization separation means for separating illumination light from the illumination means into two polarized lights whose vibration directions are orthogonal to each other; Magnifying optical means for refracting the image light so that an enlarged virtual image of the image from the means is observed by the user's eyes, and one polarized light separated from the illumination light from the illumination means by the polarization separation means. Is incident on one reflective display element, the other polarized light is incident on the other reflective display element, and the two image lights reflected from each reflective display element are again synthesized by the polarization separating means. An illumination unit, a polarization separation unit, a reflective display element, and an enlargement optical unit are arranged so as to be incident on the enlargement optical unit.

According to the first aspect of the invention, the illuminating light emitted from the illuminating means is separated into two polarized lights, and the respective polarized lights and the respective image lights formed by the corresponding reflective display elements are re-used. Since the synthesized light is made to enter the user's eyes, the illumination light can be visually recognized by the user as image light extremely efficiently. In addition, since the polarization splitting unit has a function of converting the illumination light into linearly polarized light and a function of detecting the returned image light, the conventional polarizing unit is unnecessary, and light loss there can be prevented. Further, from the opposite point of view, an image having the same brightness as that of the related art can be obtained by the illumination unit having a lower power than the related art, so that the power of the head mounted display device can be reduced.

According to a second aspect, in the configuration of the first aspect,
The two reflective display elements are arranged such that their long sides are parallel to each other in the left-right direction with respect to the user when the device is mounted on the head of the user. .

[0008] The space required for arranging the polarization separation means is substantially determined by a rectangular parallelepiped formed by the lengths of the long side and the short side of the reflective display element. According to the configuration of claim 2, the length of the long side determines the height of the rectangular parallelepiped, and the length of the short side determines the area of the rectangular parallelepiped. The space, that is, the head-mounted display device can be reduced in size.

According to a third aspect, in the configuration of the first aspect,
The two reflective display elements are arranged so as to be shifted from each other in a plane including the display surface of the reflective display element.

According to the third aspect of the present invention, for example, the resolution of the finally displayed image can be increased by shifting the pixels forming both display elements vertically and horizontally by a half pixel pitch.

According to a fourth aspect, in the configuration of the first aspect,
The two reflective display elements are arranged in a plane including the display surface of the reflective display element so as to be shifted from each other in the left and right directions with respect to the user when the apparatus is mounted on the head of the user. It is characterized by having.

According to the fourth aspect of the present invention, the two reflective display elements are arranged in alternate directions, so that a special reflective LCD having a different aspect ratio is not used.
An optical system for enlarging the aspect ratio of the finally displayed image in the left-right direction can be realized. Further, it is also possible to widen the horizontal angle of view up to twice the image of one reflective display element. At that time, the space required for arranging the polarization separation means can be suppressed to a minimum increase.

According to a fifth aspect, in the configuration of the first aspect,
The image display device further includes an image synthesizing unit between the image display unit and the user's eye for reflecting image light, transmitting light from an external scene incident from the front of the user, and causing both to enter the user's eye. It is characterized by the following.

According to the fifth aspect of the invention, a so-called see-through optical system can be realized in which an image formed by the image display device and an external scene image in front of the user can be simultaneously viewed. At this time, since the image light from the image display means is bright, even if the outside scene image becomes bright to some extent, stable image recognition becomes possible.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

(First Embodiment) FIGS. 1 and 2 are explanatory views of an optical system showing a first embodiment of the present invention. FIG.
FIG. 2 is a perspective view.

The virtual image forming optical system 1 shown in FIG. 1 comprises two reflective LCDs 2a and 2b as reflective display elements, a flat fluorescent tube 3 as illumination means, and a polarization beam splitter 4 as polarization separation means. An image display means 5 and a lens 6 serving as a magnifying optical means are roughly constituted, and a user's eye 7
Is held by a mechanism (not shown) in front of the camera.

The reflection type LCDs 2a and 2b display an image according to an image signal supplied from an external driving circuit (not shown), and reflect image light by reflecting illumination light from the flat fluorescent tube 3 to represent image information. In the transmissive LCD, the electrode portion, which was a light shielding portion, can be used as a pixel, so that the aperture ratio and the contrast can be improved. The polarizing beam splitter 4 is a flat fluorescent tube 3.
Function to separate the illumination light from the camera into two linearly polarized lights whose vibration directions are orthogonal to each other,
And a function of combining two linearly polarized lights and emitting them as one light flux. The lens 6 has a function of refracting image light so that an enlarged virtual image of an image displayed on the reflective LCDs 2a and 2b is observed by the user's eyes 7.

The polarizing beam splitter 4 has a reflecting surface 4a inclined at 45 ° with respect to the visual axis 8 of the user's eye 7, and the polarizing beam splitter 4 is sandwiched between the reflecting surface 4a and the vertical plane with respect to the user. The fluorescent tube 3 and the reflection type LCD 2b face each other, and the reflection type LCD 2
a and the lens 6 are arranged so as to face each other. The distances from the lens 6 to the liquid crystal surfaces (display surfaces) of the reflective LCD 2a and the reflective LCD 2b are equal to each other.

FIG. 2 shows the arrangement direction of the reflection type LCDs 2a and 2b, and is shown together with the polarization beam splitter 4. Although the polarizing beam splitter 4 is shown in the form of a prism for convenience of description, it may be a flat type as shown in FIG. The external shape of each of the reflective LCDs 2a and 2b is generally a rectangular parallelepiped from the relationship with the aspect ratio of the display surface.
It is often horizontal. In relation to FIG. 2, the dimension 11 of the long side is larger than the dimension 12 of the short side and is horizontally long. By the way, when the reflection type LCDs 2a and 2b and the polarizing beam splitter 4 are arranged in the relationship of FIG. 1, the space required for arranging the polarizing beam splitter 4 is generally defined by the dimensions 13 and 14 in FIG. Dimension 13 depends on dimension 12, and dimension 14 depends on dimension 11. Therefore,
As shown in FIG. 2, when the long sides (indicated by dimension 11) of the reflective LCDs 2a and 2b are arranged in parallel, the space required for arranging the polarizing beam splitter 4 is reduced, and a virtual image is formed. The forming optical system 1 can be downsized, and the present embodiment conforms thereto.

As shown in FIG. 1, the illumination light emitted from the flat fluorescent tube 3 is illuminated by a polarization beam splitter 4 as illumination light 9S as S-polarized light whose vibration direction is orthogonal to the plane of incidence of the polarization beam splitter 4. And the illumination light 9P as the same parallel P-polarized light. The separated illumination lights 9S and 9P are respectively reflected by the corresponding reflective LCDs 2a,
b, and are reflected by the respective reflective LCDs 2a and 2b to become image lights 10P and 10S representing image information. The vibration directions of the image lights 10P and 10S are rotated by 90 ° with respect to the vibration directions of the illumination lights 9S and 9P, respectively, and when the image light 10P is again incident on the polarization beam splitter 4, the image light 10P passes through the polarization beam splitter 4 Since the image light 10S is reflected by the polarizing beam splitter 4, both image lights are combined with each other. The combined image light 10 undergoes a refraction effect by the lens 6 and is observed as a virtual image enlarged by the user's eye 7.

As described above, according to the present embodiment, since the reflection type LCD is used as a means for displaying an image, the image can be brightened in accordance with the improvement of the aperture ratio. Further, the illumination light emitted from the flat fluorescent tube 3 is separated into two polarized lights, and each polarized light and the corresponding reflection LC
Each image light formed by D2a, 2b is
Since the light is synthesized again and made to enter the user's eye 7, the loss of light is small, and the illumination light can be visually recognized by the user as image light extremely efficiently. Further, since the polarizing beam splitter 4 has a function of converting the illumination light into linearly polarized light and a function of detecting the returned image light, the conventional polarizing means becomes unnecessary, and light loss there can be prevented. Further, from the opposite point of view, an image having the same brightness as that of the related art can be obtained by the illumination unit having a lower power than the related art, so that the power of the head mounted display device can be reduced.

The two reflective LCDs 2a and 2b
May be arranged such that the corresponding pixels are aligned with each other, or may be arranged so as to be shifted from each other in a plane including the display surface. FIG. 3 is a partially enlarged view of a display image for explaining the latter. In this example, both corresponding pixels, for example, pixel A and pixel A ', are shifted by a half pixel pitch in the horizontal direction and by a half pixel pitch in the vertical direction, so that they are finally visually recognized by the user. Improved image resolution. Many techniques are disclosed in, for example, Japanese Utility Model Laid-Open Publication No. 6-68023, but the feature of the present application is that it is possible to achieve high resolution while realizing high brightness of an image using illumination light that could not be used conventionally. It is.

(Second Embodiment) FIG. 4 is an explanatory view of an optical system showing a second embodiment of the present invention. FIG. 4 (a) is a perspective view, and FIG. 4 (b) is visually recognized by a user. It is explanatory drawing of an image. Note that components that are the same as or similar to those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

In FIG. 4A, two reflective LCDs are used.
The relative positional relationship between 2a and 2b, the polarization beam splitter 15, and the flat fluorescent tube 16 is the same as that in FIG. Compared with the first embodiment shown in FIG. 1, the polarizing beam splitter 15, the flat fluorescent tube 16, and the lens (not shown) are arranged in the left and right directions of the user indicated by the arrow 17 in FIG. It has been expanded. The two reflective LCDs 2a and 2b are arranged so as to be shifted from each other in the left and right directions of the user indicated by arrow 17 in a plane including the respective display surfaces. Although the two reflective LCDs 2a and 2b are driven by a drive circuit (not shown), if a drive signal to the reflective LCDs 2a and 2b is controlled in accordance with the amount of shift, FIG.
As shown in (b), the image 19 corresponding to the image width 18a
a and the image 19b corresponding to the image width 18b are visually recognized by the user's eyes 7 as a continuous horizontally long image. FIG.
The width 20 in (b) is the relative shift amount in this case.

As described above, this embodiment is characterized in that a display image having an arbitrary aspect ratio can be up to twice the image of one reflection type LCD without using a special reflection type LCD having a different aspect ratio. Can be realized. In the present application, such movement is possible because the reflection type LCDs 2a and 2b are arranged in alternate directions, and for the same reason, the movement up to twice the maximum is performed by the reflection type LCD 2a.
The frame substrates a and 2b are physically enabled without being aware of them. Also, as described in the first embodiment,
With the movement direction described above, the space required for arranging the polarization separation means can be suppressed to a minimum increase.

In this embodiment, the image 19a and the image 19b
Only the overlapping part with is valid. Also, the display may be fixed to a specific aspect ratio or may be a variable aspect ratio display.
One or both of the moving reflective LCDs may be used. However, if one is fixed in front of the user's eyes and the other can be moved outward with respect to the user's face,
It is desirable as a display with a variable aspect ratio.

(Third Embodiment) FIGS. 5 and 6 are side views of an optical system showing a third embodiment of the present invention, and are both see-through type head mounted type using the image display means 5 of the present invention. 9 is an example of a display device.

In the see-through type, the half mirror 21 shown in FIG. 5 or the half mirror 22 shown in FIG. This is a head-mounted display device that allows the user to simultaneously visually recognize the image light and the light of the outside scenery in the forward direction of the user. That is, the half mirror 21 or the half mirror 22 reflects the image light from the virtual image forming optical system 1 and transmits the light from the outside scene in the front direction of the user, thereby causing both to enter the eye 7 of the user. Functioning as an image synthesizing means.

FIG. 5 uses a lens 6 as the magnifying optical means as in FIG. 1, and a half mirror 21 is arranged between the lens 6 and the eye 7 of the user. Half mirror 2
Reference numeral 1 denotes, for example, a characteristic in which both the reflectance and the transmittance are 50%, so that 50% of the image light emitted from the image display means 5 is reflected by the half mirror 21 and the eye 7 of the user.
Is incident on. Further, 50% of the light from the outside scene in the front direction of the user is transmitted by the half mirror 21 and enters the user's eye 7.

The user visually recognizes both images at the same time, but the relative brightness, contrast, resolution, and the like between the image light and the outside scenery light affect the subjectivity and visibility of both images. In the present invention, as described in the first embodiment,
The object of the present invention is to improve the contrast and resolution of image light mainly for the purpose of causing a user to visually recognize illumination light as image light very efficiently with little loss of light. Therefore,
Because it has an advantage over outside scenery light in terms of visibility of image light,
Even if the outside scene image becomes brighter to some extent, stable image recognition becomes possible.

FIG. 6 shows a configuration in which a concave mirror 23 is used as the magnifying optical means. The half mirror 22 is arranged in a state rotated by 90 ° from the half mirror 21 in FIG. The concave mirror 23 is arranged so as to face the image display means 5 with the half mirror 22 interposed therebetween. The concave mirror 23 is used for forming a reflection optical system and reducing optical aberrations.

The image light emitted from the image display means 5 is transmitted through the half mirror 22, is refracted by the concave mirror 23, is reflected by the half mirror 22, and enters the user's eye 7. Accordingly, although the brightness of the image light is reduced as compared with the optical system of FIG. 5 because the light passes through the half mirror 22 twice, it is still more advantageous in terms of brightness than the conventional optical system of the same type.

FIG. 6 shows the case where the concave mirror 23 faces the image display means 5 via the half mirror 22. However, the concave mirror 23 may be arranged so as to face the user's eye 7 via the half mirror 22. It is possible.

[0035]

As described above, the head-mounted display device of the present invention has two elements as a display element for forming an image.
A configuration in which two reflective light-emitting elements are used to illuminate a corresponding reflective light-emitting element with illumination light separated into two polarized lights, and image light obtained from each of the light is combined again to be incident on a user's eye. Therefore, the user can visually recognize the illumination light as image light extremely efficiently. In addition, since the polarization splitting unit has a function of converting the illumination light into linearly polarized light and a function of detecting the returned image light, the conventional polarizing unit is unnecessary, and light loss there can be prevented. Further, from the opposite point of view, an image having the same brightness as that of the related art can be obtained by the illumination unit having a lower power than the related art, so that the power of the head mounted display device can be reduced.

At this time, since the two reflective display elements are arranged such that the long sides thereof are parallel to each other, the space required for arranging the polarization separating means is reduced, that is, The size of the wearable display device can be reduced.

By arranging the two reflective display elements so as to be shifted from each other in a plane including the display surface, the resolution of the finally displayed image can be increased.

Similarly, by shifting the two reflective display elements mutually in the left and right directions with respect to the user,
Without using special reflective LCD of different aspect ratio,
It is also possible to realize a display image having an arbitrary aspect ratio up to twice the image of one reflection type LCD.

Further, by disposing the image synthesizing means between the image display means and the eyes of the user, it is possible to easily realize a see-through optical system having excellent visibility of image light. At this time, since the image light from the image display means is bright, stable image recognition is possible even if the outside scene image becomes bright to some extent.

[Brief description of the drawings]

FIG. 1 is a side view of an optical system according to a first embodiment of the present invention.

FIG. 2 is a perspective view of an optical system according to the first embodiment of the present invention.

FIG. 3 is a partially enlarged view of a display image according to the first embodiment of the present invention.

4A and 4B are explanatory diagrams of an optical system according to a second embodiment of the present invention, wherein FIG. 4A is a perspective view and FIG. 4B is an explanatory diagram of an image visually recognized by a user.

FIG. 5 is a side view of an optical system according to a third embodiment of the present invention.

FIG. 6 is a side view of an optical system according to a third embodiment of the present invention.

FIG. 7 is a side view of an optical system showing a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Virtual image formation optical system 2 Reflection type LCD 3 Planar fluorescent tube 4 Polarization beam splitter 5 Image display means 6 Lens 7 User's eye 8 Visual axis 9 Illumination light 10 Image light 11 Dimension 12 Dimension 13 Dimension 14 Dimension 15 Polarization beam splitter 16 Flat fluorescent tube 17 Arrow 18 Image width 19 Image 20 Width 21 Half mirror 22 Half mirror 23 Concave mirror 24 Illumination means 25 Half mirror 26 Reflective LCD 27 Enlarged concave mirror 28 User's eye

Claims (5)

[Claims] 1. A head mounted display device mounted on a user's head, comprising: two reflective display elements for displaying an image by reflected light; and a light source for illuminating the reflective display elements. Image display means comprising illumination means, and polarization separation means for separating illumination light from the illumination means into two polarized lights whose vibration directions are orthogonal to each other; and an image from the image display means is enlarged. Magnifying optical means for refracting the image light so that the virtual image is observed by the eyes of the user, and the one polarized light separated by the polarization separating means from the illumination light from the illumination means. The light is made incident on one of the reflective display elements, the other polarized light is made incident on the other reflective display element, and the two image lights reflected from the respective reflective display elements are combined again by the polarization separation means. I The expansion so as to be incident on the optical unit, the illuminating means, the polarization separating means, reflection type display device,
A head-mounted display device, wherein an enlargement optical unit is arranged. 2. The head-mounted display device according to claim 1, wherein the two reflection-type display elements are mounted on the head of the user such that the long sides of each outer shape are opposite to each other. When
A head-mounted display device, wherein the display device is arranged so as to be parallel in the left and right directions with respect to the user. 3. The head-mounted display device according to claim 1, wherein the two reflective display elements are arranged so as to be shifted from each other in a plane including a display surface of the reflective display element. A head-mounted display device characterized by being performed. 4. The head-mounted display device according to claim 1, wherein the two reflective display elements are arranged such that the two reflective display elements are mounted on a plane including a display surface of the reflective display element. A head-mounted display device, wherein the head-mounted display device is arranged so as to be shifted from each other in the left-right direction with respect to the user when worn on the head. 5. The head mounted display device according to claim 1, wherein the image light is reflected between the image display means and the user's eyes and is incident from the front of the user. A head-mounted display device, further comprising an image synthesizing means for transmitting light from the camera and causing the light to enter both eyes of the user.