JP2001343608A - Image display device and image display system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent upsizing over the entire part of an illumination unit including light sources and a reflection image display element and the above device when the illumination light from the light sources is made incident directly on the image display element. SOLUTION: This improving display device has the light source units 1a and 1b which emit the illumination light, the reflection image display element 4 which displays images by the internal reflection of the incident illumination light, a projection optical system 6 which projects the images displayed on this reflection image display element 4 to the eyes 7 of an observer and a light guide optical system 3 which introduces the illumination emitted from the light source units to the image light exit side of the reflection image display element and makes the image light emitted from the reflection image display element incident on the projection optical system. The light guide optical system is so constituted as to make the illumination light from the light source units incident on a plurality of regions 4a and 4b on the reflection image display element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device used as a head mounted display or a finder of a camera.

[0002]

2. Description of the Related Art Head Mounted Display (HMD)
2. Description of the Related Art Various optical systems for reducing the size of an image display device such as an image display device or a glasses-type display have been proposed. For example, JP-A-7-333551, JP-A-8-50256 and JP-A-8-160340 disclose a liquid crystal display as a display means for displaying image information and a viewing optical system (projection optical system). An image display device using a small prism and miniaturizing the entire device has been proposed.

An image display device proposed in the above-mentioned Japanese Patent Application Laid-Open No. Hei 7-333551, etc., allows light emitted from a liquid crystal display displaying image information to enter a small prism.
The small prism is emitted through the refraction surface, the total reflection surface, and the reflection surface having the curvature formed in the small prism and guided to the eyeball of the observer. As a result, a virtual image of the liquid crystal display is formed in front of the observer, and the observer can observe the virtual image.

[0004] In these conventional image display devices, a transmissive liquid crystal display is used as an image display means. In recent years, the transmissive liquid crystal display has a low pixel aperture ratio due to the high definition of image display elements. However, it is pointed out that the image quality deteriorates.

[0005]

Under such circumstances, it has been proposed to use a reflection type liquid crystal display having a high pixel aperture ratio in an image display device requiring a high definition image. As an example of a display optical system using a reflection type liquid crystal display, there is one proposed in JP-A-11-125791.

As shown in FIG. 11 of the present application, the image display apparatus has a configuration in which light from a light source 112 is directly incident on a reflection type liquid crystal display 108 without passing through an optical element.

However, if the light from the light source 112 is directly incident on the liquid crystal display 108, a problem arises in that the size of the lighting unit including the light source 112 and the liquid crystal display 108 and the entire device becomes large.

In addition, since the liquid crystal display 108 is configured to be greatly inclined with respect to the display optical system (projection optical system) 110, the optical path length from the display optical system 110 to the liquid crystal display 108 varies greatly depending on the object height, and the optical performance is reduced. There is a problem of lowering.

[0009] As another image display device, an image display device as shown in FIG. 12 has been proposed. In this image display apparatus, a light source 112 is provided on a side opposite to a liquid crystal display 108 with respect to a prism-shaped display optical system 110, and a light source 11 is provided.
2 is transmitted through the display optical system 110, and then illuminates the liquid crystal display 108. Of the illumination light, the light reflected by the liquid crystal display 108 again enters the prism-shaped display optical system 110 for observation. Is guided to the eyeball 101 of the person.

However, in such an illumination system, there is a problem that unnecessary reflection occurring inside the prism-shaped display optical system 110 generates flare light which is a major factor of image quality deterioration.

Accordingly, the present invention is an image display apparatus which has a very simple and compact structure, is excellent in correcting various aberrations, has a wide angle of view, and does not generate unnecessary flare. It is an object of the present invention to provide an image display device using a reflective image display device corresponding to a high-definition image such as an output.

[0012]

In order to solve the above-mentioned problems, a light source unit for emitting illumination light, a reflection type image display element for displaying an image by internal reflection of incident illumination light, and a reflection type image display are provided. A projection optical system for projecting an image displayed on the element to the observer's eyes, and an illumination light emitted from the light source unit is guided to the image light emission side of the reflection type image display element and emitted from the reflection type image display element. A light guide optical system for causing the projected image light to enter the projection optical system, wherein the light guide optical system causes the illumination light from the light source unit to enter a plurality of regions on the reflective image display element. It is composed.

More specifically, for example, a plurality of light source units are provided, and the light guide optical system is configured so that illumination light from the plurality of light source units is respectively incident on different regions on the reflection type image display element. An illumination light beam from one light source unit is separated into a plurality of light beams, and the separated illumination light beams are respectively incident on different regions on the reflective image display device.

Thus, the light guide optical system can be made thinner and the reflection type image can be reduced, as compared with the case where the illumination light from one light source unit is guided to the entire screen of the reflection type image display device via one reflection surface. It is possible to achieve uniform illumination of the display element. In addition, the angle of incidence of the illumination light on the reflective image display element and the angle of emission of the image light from the reflective image display element can be made substantially uniform and small in the screen. It is possible to realize a small-sized image display element which can be manufactured.

Note that, as described above, the light guide optical system is
By separating the illumination light beams from the two light source units into a plurality of light beams and making the separated illumination light beams enter different regions on the reflection type image display device, the reflection type image display device can be realized with a small number of light sources. It is possible to provide an image display device that can provide uniform illumination and that has a small loss of illumination light.

Further, by forming an antireflection film on the optically active surface of the light guide optical system or by forming a light absorbing layer on a surface other than the optically active surface, reflection on the optically active surface and optically active surface can be prevented. Unnecessary light that causes flare or ghost may be prevented from being generated by re-incident light incident on the other surface into the device.

Further, after the assembly and adjustment of the apparatus, the light guide optical system and the reflection type image display element are bonded and fixed to prevent the relative position change between the light guide optical system and the reflection type image display element in a subsequent step. However, the best performance at the time of adjustment may be maintained.

In this case, the adhesive having a refractive index substantially equal to the refractive index of light of the material of the cover glass provided in the optical element constituting the light guiding optical system and the reflection type image display element is used as the adhesive. The surface reflection on the interface between the optical element and the cover glass and the adhesive may be reduced as compared with the case where no adhesive is used, so that an image with high contrast may be displayed.

Further, at least one of the projection optical elements
By using at least one of the optical working surfaces including the two reflecting surfaces is a rotationally asymmetric surface, it is possible to display a high-quality image in which various aberrations (distortion and the like) are corrected.

[0020]

(First Embodiment) FIGS. 1 and 2
1 shows an image display device according to a first embodiment of the present invention. FIG. 1 is a sectional view of the image display device, and FIG. 2 is an enlarged sectional view of an illumination system 19 of the image display device.

In these figures, 1a and 1b are RGB
(Light source unit) which emits light of which the light emission is controlled by a lighting control unit (not shown).

Reference numerals 2a and 2b denote a first polarizing plate, 3 denotes an illumination element constituting a light guide optical system, 4 denotes a reflection type liquid crystal display panel (reflection type image display element: hereinafter simply referred to as a display panel), and 5 denotes a display panel. A second polarizing plate 6 is a prism lens constituting a projection optical system, and 7 is an observer's pupil.

The lighting element 3 includes a display panel 4,
The light source units 1 a and 1 b are arranged between the second polarizing plate 5 and the prism lens 6, and the light source units 1 a and 1 b are arranged with respect to the illumination element 3 by disposing the display panel 4, the second polarizing plate 5 and the prism lens 6. It is arranged in a direction (same as the left-right direction) orthogonal to the direction (the up-down direction in FIG. 2).

The illumination light emitted from the light source unit 1a passes through the first polarizing plate 2a and passes through the first surface 8 of the illumination element 3.
a, is reflected by the polarizing beam splitter surface (light beam splitting surface) 9a, passes through the second surface 10, and then illuminates the area 4a of the display panel 4.

A part of the illumination light incident on the area 4a of the display panel 4 is reflected in the display panel 4 and transmitted as image light through the surface 10, the polarizing beam splitter 9a and the third surface 11 of the illumination element 3. , And enters the prism lens 6 through the second polarizing plate 5.

On the other hand, the light emitted from the light source unit 1b similarly passes through the first polarizing plate 2b,
After being transmitted through the surface 8b, reflected by the polarizing beam splitter surface (light beam separation surface) 9b, and transmitted through the second surface 10, the region 4b of the display panel 4 is illuminated.

A part of the light beam incident on the area 4b of the display panel 4 is reflected inside the display panel 4, and
The light passes through the surface 10, the polarizing beam splitter surface 9b, and the third surface 11 of the illumination element 3, passes through the second polarizing plate 5, and enters the prism lens 6 as image light.

Further, as shown in FIG. 1, the first surface 1 of the prism lens 6 having three optically active surfaces
The image light incident on 2 is reflected by the second and third surfaces 13 and 14, then passes through the second surface 13 and reaches the pupil 7 of the observer.

The prism lens 6 has a positive refractive power, and has an effect of changing an image displayed on the display panel 4 into an enlarged virtual image.

Each of the first to third surfaces 12, 13, and 14 of the prism lens 6 is formed as a rotationally asymmetric free-form surface. The image light for projecting the enlarged image to the eyes of the user is projected.

The image display device is connected to an image information output device (not shown) such as a video, television, personal computer, DVD player, etc., and forms an image display system.
When an image is supplied from the image output device to the image display device, the image is displayed on the display panel 4, and the image enlarged by the prism lens 6 is observed by the observer.

Next, the configuration and optical function of the illumination element 3 will be described in more detail. Here, a ray connecting the center of the exit pupil (pupil 7 of the observer) of the projection optical system and the center of the display panel 4 is set as a reference axis ray, the center of the exit pupil is set as an origin, and a reference axis light intersecting the origin is set. On the line, the Z axis (the direction from the origin to the projection optical system is defined as positive), the direction perpendicular to the Z axis on the cross section including the reference axis ray is defined as the Y axis,
An absolute coordinate system of the image display device is defined with the axis perpendicular to the Z axis as the X axis. In addition, since the illumination light from the light source unit 1a and the illumination light from the light source unit 1b are symmetric with respect to a plane passing through the center of the display panel 4, the configuration of the illumination element 3 relating to the illumination light from the light source unit 1a is used here. Only the optical action will be described.

The illumination element 3 is configured such that the transmission surface 11 on the prism lens 6 side and the transmission surface 10 on the display panel 4 side are parallel. The angle between the polarizing beam splitter surfaces 9a and 9b and the transmitting surfaces 10 and 11 is set to 45 °.

As shown in FIG. 2, the unpolarized illumination light 14 from the light source unit 1a is aligned in the first polarization direction 15 by the first polarizing plate 2a, and is aligned on the polarization beam splitter surface 9a of the illumination element 3. The light is reflected and transmitted through the second surface 10 of the lighting element 3 to illuminate the area 4 a of the display panel 4.

Of the light that has entered the display panel 4, the light that has undergone a 90 ° rotation in the display panel 4 is:
Polarization beam splitter surface 9a, transmission surface 11 and second
Through the polarizing plate 5. Further, of the light that has entered the display panel 4, the light that does not receive optical rotation at the display panel 4 is reflected by the polarization beam splitter surface 9 a in the direction of the light source unit 1 a.

The arrow in FIG. 2 indicates one of the P-polarized light and the S-polarized light with respect to the polarization beam splitter surface 9a, and the encircled mark indicates the other state.

Next, numerical examples will be shown. In this embodiment,
Since the optical system is composed of eccentric surfaces, an absolute coordinate system and a local coordinate system are set to represent the shape of the optical system.
FIG. 13 is an explanatory diagram of an absolute coordinate system and a local coordinate system.
This will be described.

The origin of the absolute coordinate system is set at the center O of the desired pupil position of the observer, and the Z axis is a straight line passing through the point O and perpendicular to the pupil plane, and is a symmetrical plane of the optical system (the plane of the drawing). )It's above. The Y-axis is a straight line passing through the origin O and making an angle of 90 ° counterclockwise with respect to the Z-axis on the symmetry plane. The X axis is a straight line passing through the origin O and orthogonal to the Y and Z axes.

The origin Oi of the local coordinates is defined by the absolute coordinates (S
Xi, SYi, SZi) are set for each surface Si. The Z axis of the local coordinates is a straight line passing through the origin Oi in the YZ plane and forming an angle Tilt i with the Z axis of the absolute coordinate system. Where angle
Tilt i is positive when the Z axis of the local coordinates makes an angle in the counterclockwise direction with respect to a straight line passing through the origin Oi and parallel to the Z axis of the absolute coordinate system.

The Y axis of the local coordinates is a straight line passing through the origin Oi and forming an angle of 90 ° counterclockwise with respect to the Z axis of the local coordinates. The X axis of the local coordinate is a straight line passing through the origin Oi and orthogonal to the Y axis and the Z axis of the local coordinate.

The shape of each surface is represented by local coordinates. In each of the above embodiments, the shape of the optically acting surface has a shape having an aspheric surface based on a Zernike polynomial in a shape function representing a quadratic surface, and is represented by the following function.

[0042] Here, r is the basic radius of curvature of each surface, and c is c = 1 /
r. Also, ci is the aspheric coefficient of the i-th Zernike polynomial in each surface.

The image display device of this embodiment is suitable for an example of the arrangement of the image display device as shown in FIG. In the present embodiment, the light source units 1a and 1b, the display panel 4,
The first and second polarizing plates 2a, 2b, 5 and the lighting element 3
The layout is such that it is positioned above the height of the prism lens 6 and the left and right eyes of the observer.

Table 1 shows numerical data and f of each surface of the image display device of this embodiment. Here, Si corresponds to FIG.
As shown in FIG. 7, the surface information of the exit pupil center (7), the prism lens 6, the illumination element 3, the cover glass of the display panel 4, and the image display surface of the display panel 4 are shown in order from i = 1.

The maximum half angle of view of the apparatus in the X-axis direction is W
X, the maximum half angle of view of the apparatus in the Y-axis direction is described as WY.

F is a value corresponding to the focal length of the prism lens 6, and the angle of incidence WY of the incident light from the object at infinity on the section YZ of the device in the reverse trace from the eye 7 of the observer.
And f = y _m / tan (WY) calculated from the image height at which the light beam forms an image on the display panel 4, and is simply referred to as a focal length here.

<< Table 1 >> Focal length f 20.8mm wx = 13.0 deg, wy = 9.8 deg prism n = 1.571 s1 r: ∞ d: 33.35 n: 1.0000 s2 dY -60.76 dZ 33.35 Tilt -4.93 r: -400.781 c4: -5.930e-04 c5: -3.713e-04 c9: -4.111e-07 c10: -2.722e-06 c11: 4.183e-08 c12: 1.463e-09 c13: -3.213e-09 c19: -2.811e -11 c20: 5.196e-12 c21: 5.061e-10 c22: -3.721e-12 c23: -2.754e-13 c24: 1.838e-13 c25: -3.545e-13 s3 dY -3.55 dZ 38.72 Tilt -25.82 r: -57.618 c4: -1.477e-03 c5: -1.114e-03 c9: -5.798e-06 c10: -8.359e-06 c11: -2.044e-07 c12: 1.182e-08 c13: -1.536e -07 c19: 1.822e-09 c20: -3.631e-09 c21: 2.947e-09 c22: 6.073e-11 c23: 1.277e-10 c24: -2.660e-11 c25: 8.384e-12 s4 dY -60.76 dZ 33.35 Tilt -4.93 r: -400.781 c4: -5.930e-04 c5: -3.713e-04 c9: -4.111e-07 c10: -2.722e-06 c11: 4.183e-08 c12: 1.463e-09 c13 : -3.213e-09 c19: -2.811e-11 c20: 5.196e-12 c21: 5.061e-10 c22: -3.721e-12 c23: -2.754e-13 c24: 1.838e-13 c25: -3.545e -13 s5 dY 10.38 dZ 47.05 Tilt 55.21 r: -118.514 c4: 2.445e-02 c5: -5.629e-03 c9: 3.886e-04 c10: -4.956e-04 c11: -2.415e-07 c12: -1.959e-05 c13: -2.746e-08 c19: -2.360e-07 c20: 3.568e-07 c21: -2.486e-07 c22: 0.000e + 00 c23: 0.000 e + 00 c24: 0.000e + 00 c25: 0.000e + 00 s6 (dummy surface) dY 16.03 dZ 38.91 Tilt 48.86 r: ∞ d: 1.37 n: 1.0000 s7 r: ∞ d: 3.80 n: 1.4917 s8 r: ∞ d : 0.20 n: 1.0000 s9 r: ∞ d: 1.00 n: 1.4600 s10 (image plane) r: ∞ d: 0.00 n: 1.0000 As described above, in the present embodiment, the illumination area on the display panel 4 is divided into two areas. , It is possible to uniformly illuminate the display panel 4 by using the thin illuminating element 3, and at the same time, the incident and exit angles of light rays with respect to the display panel 4 are made substantially uniform and small in the screen. I can do it. Therefore, it is possible to realize a small-sized image display device capable of displaying an image of good image quality on the entire screen.

In this embodiment, the lighting element 3
Although the case where the second polarizing plate 5 is disposed between the first polarizing plate 5 and the prism lens 6 has been described, a configuration without using the polarizing plate 5 may be employed.

In this case, the polarization beam splitter 9
It is desirable to increase the degree of parallelism of the light beams incident on the a and 9b so as to reduce the influence of the deterioration of the polarization splitting characteristic due to the incident angle dependence of the polarization beam splitters 9a and 9b.

In the present embodiment, the light source unit 1
a, 1b and a first polarizing plate 2a, 2b
Has been described, but the polarizing plates 2a, 2b
A configuration without the above may be used.

In this case, the polarization beam splitter 9a
Is transmitted through the polarization beam splitter 9b and enters the light source unit 1b, but the light rays entering and exiting the display panel 4 are the same as those described in the present embodiment.

Further, in the present embodiment, the image display device having the layout as shown in FIG. 9 has been described, but the layout as shown in FIG. 10 may be used. FIG.
0, the light source units 1a, 1b,
The display panel 4, the first and second polarizing plates 2a, 2b,
5 and the illumination element 3 are arranged at the same height as the prism lens 6 and the height of both eyes of the observer.

Further, in the present embodiment and the following embodiments, the case where the projection optical system is constituted by the prism lens 6 is described, but the projection optical system is constituted by another optical system comprising a half mirror and a concave mirror. You may comprise.

(Second Embodiment) FIG. 3 shows a second embodiment of the present invention.
2 shows a configuration of an illumination system 20 of the image display device according to the embodiment. Note that, in the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals.

In the present embodiment, the light source units 21a, 21a
1b, light sources 22a and 22b and light guide plates 24a and 24b
And reflectors 23a, 23b arranged outside the light guide plates 24a, 24b, and prism sheets 25a, 25 arranged inside the light guide plates 24a, 24b (the lighting element 3 side).
b. The configuration of the lighting element 3 is as follows.
This is the same as that of the first embodiment. The configuration of the projection optical system is the same as that of the first embodiment.

In the image display device of this embodiment, the light from the light source 22a is emitted from the light source unit as a substantially parallel light beam via the reflection surface 23a, the light guide plate 24a and the prism sheet 25a.

The unpolarized light 14 from the light source unit 21a
Of the light, the light in the first polarization direction 15 is reflected by the polarizing beam splitter surface (first light beam splitting surface) 9 a of the illumination element 3, passes through the second surface 10 of the illumination element 3, and The area 4a is illuminated.

Of the light that has entered the area 4a of the display panel 4, the light that has undergone a 90 ° rotation at the display panel 4 has passed through the polarizing beam splitter surface 9a, the transmitting surface 11, and the second polarizing plate 5, and has a prism. The light enters the lens 6.

Light that is not rotated by the display panel 4 is reflected by the polarization beam splitter surface 9a in the direction of the light source unit 21a to become re-incident light 26a.

On the other hand, the light in the second polarization direction 16 of the unpolarized light 14 from the light source unit 21a passes through the polarizing beam splitter surfaces 9a and 9b of the illumination element 3, enters the light source unit 21b, and is re-transmitted. It becomes incident light 27a. Similarly, part of the light from the light source 22b is re-incident light 26b, 27
b.

Although not shown, the light source unit 21
The light in the first polarization direction out of the unpolarized light from b is reflected by the polarization beam splitter surface (second light beam separation surface) 9 b of the illumination element 3 and transmitted through the second surface 10 of the illumination element 3. Then, the area 4b of the display panel 4 is illuminated.

Of the light that has entered the area 4b of the display panel 4, the light that has been rotated by 90 ° at the display panel 4 is transmitted through the polarizing beam splitter surface 9b, the transmitting surface 11, and the second polarizing plate 5 to be prisms. The light enters the lens 6.

Light that is not rotated by the display panel 4 is reflected by the polarization beam splitter surface 9b in the direction of the light source unit 21b, and becomes re-incident light 26b.

On the other hand, the light in the second polarization direction out of the unpolarized light from the light source unit 21b is transmitted through the polarization beam splitter surfaces 9b and 9a of the illumination element 3, and
1a and re-incident light 27b.

Then, the above-mentioned re-incident light 26a, 26b,
27a and 27b are reflected by the reflectors 23a and 23b,
The light is again emitted as unpolarized light 14 toward the illumination element 3.

According to this embodiment, the same effect as that of the first embodiment can be obtained, and at the same time, it is possible to realize an image display apparatus with a small light amount loss with respect to the illumination light of the display 4 (third embodiment). FIG. 4 shows a configuration of an illumination system 30 of the image display device according to the third embodiment of the present invention.
Note that, in the present embodiment, components common to the second embodiment are denoted by the same reference numerals as in the second embodiment.

In this embodiment, a λ / 4 plate 32 and a reflection plate 33 for generating a secondary light source are arranged in place of the light source unit 21b in the second embodiment. The configuration of the lighting element 3 is the same as that of the first and second embodiments. The configuration of the projection optical system is the first
This is the same as that of the embodiment.

The light in the first polarization direction 15 of the unpolarized light 14 emitted from the light source unit 21a as a substantially parallel light flux is reflected by the polarization beam splitter surface (first light beam separation surface) 9a of the illumination element 3. The second surface 10 of the lighting element 3
To illuminate the area 4 a of the display panel 4.

On the other hand, the light in the second polarization direction 16 of the unpolarized light 14 from the light source unit 21a passes through the polarization beam splitter surfaces 9a and 9b of the illumination element 3 and
The light re-enters the polarization beam splitter surface (second light beam separation surface) 9b of the illumination element 3 via the four plates 32 and the reflection plate 33.

The re-incident light 36a reciprocates through the λ / 4 plate 32, receives a 90 ° rotation, and has the same polarization direction as the polarization direction 15, so that the polarization beam splitter surface 9
b, is transmitted through the second surface 10 of the lighting element 3 and illuminates the area 4 b of the display panel 4.

Of the light that has entered the regions 4a and 4b of the display panel 4, the light that has undergone a 90-degree rotation at the display panel 4 is polarized beam splitter surfaces 9a and 9b.
The light passes through the transmission surface 11 and the second polarizing plate 5 and enters the prism lens 6.

Light that is not rotated by the display panel 4 is reflected by the polarizing beam splitter surfaces 9a and 9b in the direction of the light source unit 21a and the λ / 4 plate 32 and the reflector 33b, and becomes re-incident light.

According to the present embodiment, the same effect as that of the first embodiment can be obtained, and at the same time, the light quantity loss with respect to the illumination light of the display panel 4 is small, so that even one light source unit is sufficiently bright and has good image quality. An image display device can be realized.

(Fourth Embodiment) FIG. 5 shows a fourth embodiment of the present invention.
2 illustrates a configuration of an illumination system 40 of the image display device according to the embodiment. Note that, in this embodiment, the same components as those in the second and third embodiments are denoted by the same reference numerals. The configuration of the projection optical system is the same as that of the first embodiment.

In this embodiment, a λ / 2 plate 41 is disposed between the polarization beam splitter surfaces 49a and 49b instead of the λ / 4 plate 32 and the reflection plate 33 described in the third embodiment.

However, the polarization beam splitter surface 49b in the illumination element 43 is arranged in parallel with the polarization beam splitter surface 49a.

In the image display apparatus of the present embodiment, the light in the first polarization direction 15 of the unpolarized light 14 emitted from the light source unit 21a as a substantially parallel light flux is reflected by the polarization beam splitter surface 49a of the illumination element 3. Then, the light passes through the second surface 10 of the lighting element 3 and illuminates the area 4 a of the display panel 4.

On the other hand, of the unpolarized light 14 from the light source unit 21a, the light in the second polarization direction 16 is transmitted through the polarization beam splitter surface 49a of the illumination element 3, and the λ / 2 plate 4
Incident on 1. At this time, the polarization beam splitter surface 4
The incident light 46 to the 9b is transmitted through the λ / 2 plate 41, is rotated by 90 °, and becomes light having the same polarization direction as the polarization direction 15.

This light is transmitted to the polarizing beam splitter surface 49.
b, passes through the second surface 10 of the lighting element 3 and illuminates the area 4b of the display panel 4.

According to the present embodiment, the same effect as that of the first embodiment can be obtained, and at the same time, the light amount loss with respect to the illumination light of the display panel 4 is small, so that even one light source unit is sufficiently bright and has good image quality. An image display device can be realized.

(Fifth Embodiment) FIG. 6 shows a fifth embodiment of the present invention.
2 illustrates a configuration of an illumination system 50 of the image display device according to the embodiment. Note that, in the present embodiment, the same components as those in the above embodiments are denoted by the same reference numerals. The configuration of the projection optical system is the same as that of the first embodiment.

In this embodiment, the illumination system described in the fourth embodiment is arranged symmetrically with respect to a plane including the center 40A of the display panel 4.

In the image display apparatus of this embodiment, the illumination light emitted from the light source unit 21a as a substantially parallel light beam is applied to the area 54a (areas 4a and 4b) of the display panel 4 in the same manner as described in the fourth embodiment. Lighting). On the other hand, the illumination light emitted from the light source unit 21b is
Area 54b of display panel 4 (areas 4c and 4d)
To illuminate.

According to this embodiment, the same effects as those of the first embodiment can be obtained, and at the same time, it is possible to further reduce the thickness of the illumination element and to realize an image display apparatus with a small loss of illumination light. .

(Sixth Embodiment) FIG. 7 shows a sixth embodiment of the present invention.
2 illustrates a configuration of an illumination system 60 (configuration of the display panel 4 as viewed in a normal direction) of the image display device according to the embodiment.
Note that, in the present embodiment, the same components as those in the second embodiment are denoted by the same reference numerals. The configuration of the projection optical system is the same as that of the first embodiment.

In this embodiment, the illumination system described in the first embodiment is arranged so that the number of illumination areas in the light source unit and the display panel is four.

The boundaries 63a, 63b, 63 shown in FIG.
c and 63d are four polarization beam splitter surfaces 64
A ridge line of a quadrangular pyramid consisting of a, 64b, 64c, and 64d is shown. Also, the cross section at 6Y in FIG. 7 is the same as the cross-sectional arrangement in FIG. However, the polarization beam splitters 9a and 9b in FIG. 2 correspond to 64a and 64b in FIG.

The angle between the polarizing beam splitters 64c and 64d on the cross section 6X and the surface 10 in FIG. 2 is about 37 °, and the angle between the polarizing beam splitters 64a and 64b is 45 °. different. In this case, by optimizing the film characteristics and the like at each angle, substantially the same polarization separation characteristics can be obtained for the polarization beam splitters 64a and 64b and 64c and 64d.

In this embodiment, the light source units 1a, 1
Illumination light emitted from b, 1c, and 1d illuminates the display panel 4 by dividing the display panel 4 into four regions divided so as to correspond to the ridges.

According to the present embodiment, it is possible to realize an image display device that can display a bright image even when the light emission amount of each light source unit is small, while obtaining the same effects as those of the first embodiment. it can.

(Seventh Embodiment) FIG. 8 shows a seventh embodiment of the present invention.
2 illustrates a configuration of an illumination system 70 of the image display device according to the embodiment. Note that, in the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals. The configuration of the projection optical system is the same as that of the first embodiment.

The illumination element 73 of this embodiment, like the illumination element 3 of the first embodiment, is disposed between the prism lens 6 and the display panel 4, and the transmission surface 11 on the prism lens 6 side and the panel And the transmission surface 10 on the side. However, the illumination element 73 is composed of a first optical block 74 having a trapezoidal cross section and a second optical block 75 disposed with a small gap between the first optical block 74 and the first optical block 74. It is configured.

In the second optical block 75, the total reflection surfaces 79a and 79b as the air interface facing the gap are
The angle formed between the total reflection surface and the incident light beam is optimized so as to satisfy the total reflection condition for the incident light.

The angle formed by the total reflection surfaces 79a, 79b and the transmission surfaces 10, 11 is 30 °.

Also, as in the first embodiment, 2a, 2b
And 5 are first and second polarizing plates disposed on the incident side and the exit side with respect to the display panel 4, respectively. The unpolarized light 14 from the light source units 1a and 1b is
The first polarizers 2 a and 2 b align the light in the first polarization direction 15, are reflected by the total reflection surfaces 79 a and 79 b of the illumination element 73, respectively, pass through the second surface 10 of the illumination element 73, and The regions 4a and 4b are respectively illuminated.

According to the present embodiment, the same effects as those of the first embodiment can be obtained, and at the same time, the thickness of the illumination element can be further reduced, and an image display device capable of displaying a bright image can be realized.

In the first to seventh embodiments described above, an anti-reflection film is formed on the incident surface (one of the optical working surfaces) of the illumination element, and the occurrence of flare or ghost due to the reflection on the incident surface. May be suppressed.

Further, a light absorbing layer may be formed on a surface other than the optically active surface of the lighting element 3. Accordingly, of the illumination light incident on the illumination element, light incident on a surface other than the optically active surface of the illumination element is absorbed by the light absorbing layer and does not become flare light in the illumination element. Therefore, an image display device with less flare can be realized.

Although the black layer or the like is assumed as the light absorbing layer, a film such as an antireflection film may be formed on a surface other than the optically active surface. Further, as the anti-reflection film, a fine optical function surface (SW) having an anti-reflection effect having polarization dependency is used.
What formed S) on the sheet may be used.

Further, in the first to seventh embodiments described above, after assembling and adjusting the device, the illumination element and the cover glass of the display panel may be bonded and fixed with an adhesive.

With this configuration, there is no change in the relative position between the lighting element and the display panel, which occurs in the subsequent steps, and the best performance during adjustment is maintained and assured. Further, in this case, by using an adhesive whose index (refractive index) is substantially the same as that of the material of the cover glass of the lighting element and the display panel, the surface reflection on the interface in contact with the adhesive does not include the adhesive. Compared to the case,
It is possible to greatly reduce the image and display an image with high contrast.

In each of the above embodiments, an image display device called a so-called head-mounted display has been described. However, the present invention can be applied to an image display device as a viewfinder of a digital camera or a video camera.

[0103]

As described above, according to the present invention,
Since the illumination light from the light source unit is configured to be incident on a plurality of regions on the reflection type image display device by the light guide optical system, the illumination light from one light source unit is transmitted by one light source unit.
As compared with the case where the light is guided to the entire screen of the reflection type image display device through the two reflection surfaces, the light guide optical system can be made thinner and the reflection type image display device can be uniformly illuminated.

Moreover, the angle of incidence of illumination light on the reflective image display element and the angle of emission of image light from the reflective image display element can be made substantially uniform and small in the screen, so that the image quality in the display screen can be reduced. Can be realized, and a small-sized image display element capable of improving the image quality can be realized.

If the light guide optical system is configured to separate the illumination light beam from one light source unit into a plurality of light beams and to make these separated illumination light beams respectively enter different regions on the reflection type image display element, With a small number of light sources, it is possible to uniformly illuminate the reflection type image display element, and it is possible to provide an image display device in which the loss of illumination light amount is small.

Also, by forming an antireflection film on the optically active surface of the light guide optical system or by forming a light absorbing layer on a surface other than the optically active surface, reflection on the optically active surface and optically active surface can be prevented. Unnecessary light that causes flare and ghost can be prevented from being caused by re-incident light incident on the other surface into the device.

Further, if the light guide optical system and the reflection type image display element are bonded and fixed, the relative position of the light guide optical system and the reflection type image display element can be prevented from changing in the subsequent steps, and the adjustment can be performed at the time of adjustment. Can guarantee the best performance.

In this case, an adhesive having a refractive index substantially equal to the refractive index of light of the material of the cover glass provided in the optical element constituting the light guiding optical system and the reflection type image display element is used as the adhesive. The surface reflection on the interface where the optical element and the cover glass are in contact with the adhesive is reduced as compared with the case where no adhesive is used, and an image with high contrast can be displayed.

Also, at least one projection optical element is used.
By using one of the optical working surfaces including the two reflecting surfaces, at least one of which is a rotationally asymmetric surface, a high-quality image in which various aberrations (distortion and the like) are corrected can be displayed.

[Brief description of the drawings]

FIG. 1 is a sectional view of an image display device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of an illumination system of the image display device.

FIG. 3 is a sectional view of an illumination system of an image display device according to a second embodiment of the present invention.

FIG. 4 is a sectional view of an illumination system of an image display device according to a third embodiment of the present invention.

FIG. 5 is a sectional view of an illumination system of an image display device according to a fourth embodiment of the present invention.

FIG. 6 is a sectional view of an illumination system of an image display device according to a fifth embodiment of the present invention.

FIG. 7 is a sectional view of an illumination system of an image display device according to a sixth embodiment of the present invention.

FIG. 8 is a sectional view of an illumination system of an image display device according to a seventh embodiment of the present invention.

FIG. 9 is a mounting model diagram of the image display device of the first embodiment.

FIG. 10 is another wearing model diagram of the image display device of the first embodiment.

FIG. 11 is a cross-sectional view of a conventional image display device.

FIG. 12 is a cross-sectional view of a conventional image display device.

FIG. 13 is a diagram illustrating a coordinate system of an optical system in the image display device according to the present invention.

[Description of Signs] 1a, 1b, 21a, 21b Light source unit 2a, 2b First polarizing plate 3, 43, 63, 73 Lighting element 4 Reflective liquid crystal display panel 5 Second polarizing plate 6 Prism lens 7 Observer pupil

Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court II (Reference) // G02F 1/13 101 G02F 1/13 101 1/1335 1/1335 (72) Inventor Takashi Sudo Shimomaruko, Ota-ku, Tokyo 3-30-2 F-term in Canon Inc. (reference) 2H088 EA10 HA13 HA17 HA20 HA21 HA23 HA28 MA06 MA20 2H091 FA05Z FA10Z FA14Z LA11 MA02 2H099 AA11 BA09 CA02 CA07 CA08 DA05 5G435 AA01 BB12 BB15 DG02 FF03 GG09 GG24

Claims (28)

[Claims] 1. A light source unit that emits illumination light, a reflective image display element that displays an image by internal reflection of incident illumination light, and an image displayed on the reflective image display element is projected to an observer's eye. And the illumination light emitted from the light source unit is guided to the image light emission side of the reflective image display device, and the image light emitted from the reflective image display device is made incident on the projection optical system. An image display device comprising: a light guide optical system; wherein the light guide optical system causes illumination light from the light source unit to enter a plurality of regions on the reflective image display element. 2. The light guide optical system is disposed between the reflection type image display device and the projection optical system, and the light source unit moves the reflection type image with respect to the light guide optical system. The image display device according to claim 1, wherein the display device, the light guide optical system, and the projection optical system are arranged in a direction orthogonal to the arrangement direction. 3. A light guide optical system comprising: a plurality of light source units; and the light guide optical system configured to cause illumination light from the plurality of light source units to enter different regions on the reflective image display element. The image display device according to claim 1, wherein: 4. The image according to claim 3, wherein the light guide optical system has a reflection surface that reflects illumination light from the plurality of light source units toward the reflection type image display device. Display device. 5. The image display device according to claim 4, wherein the reflection surface is a total reflection surface. 6. The image display device according to claim 4, wherein the reflection surface is a polarization beam splitter. 7. The first light guide optical system reflects a part of an illumination light beam from one light source unit of the plurality of light source units, makes the light beam enter the reflection type image display element, and transmits the remaining light. And the illumination light transmitted through the first polarization splitting surface is transmitted to be incident on another light source unit, and the illumination light from the other light source unit is illuminated on the reflective image display element. 4. The device according to claim 3, further comprising a second light beam splitting surface that is made to enter a region different from a region where a part of the light beam enters.
An image display device according to claim 1. 8. The apparatus according to claim 7, wherein the first and second light beam splitting surfaces are polarization beam splitters.
An image display device according to claim 1. 9. The light guide optical system is configured to separate an illumination light beam from the light source unit into a plurality of light beams and to make these separated illumination light beams respectively enter different regions on the reflective image display element. The image display device according to claim 1, wherein: 10. The light guide optical system, comprising: a first light beam separation surface that reflects a part of an illumination light beam from the light source, makes the light beam enter the reflection type image display element, and transmits the remaining light beam; A secondary light source generation unit that generates a secondary light source using the illumination light beam transmitted through the light beam separation surface; and transmits the illumination light beam transmitted through the first light beam separation surface to enter the secondary light source generation unit. A second light beam separating surface for reflecting the illumination light from the secondary light source generation unit and causing the light to enter a region on the reflective image display element different from the region where a part of the illumination light beam has entered. The image display device according to claim 9, wherein: 11. The first and second light beam splitting surfaces,
The image display device according to claim 10, wherein the image display device is a polarization beam splitter. 12. The secondary light source generating unit reflects the light passing through the quarter-wave plate and the quarter-wave plate to the second light flux separation surface again through the quarter-wave plate. The image display device according to claim 11, further comprising: a reflecting member that receives the light. 13. The light guide optical system, comprising: a light beam separating surface for reflecting a part of an illumination light beam from the light source to be incident on the reflection type image display element and transmitting the remaining light beam; The image display according to claim 9, further comprising: a reflection surface that reflects the illuminated light beam and makes the illuminated light beam incident on a region on the reflective image display device that is different from a region where a part of the illuminated light beam is incident. apparatus. 14. The image display device according to claim 13, wherein the light beam splitting surface is a polarization beam splitter. 15. The image display device according to claim 14, wherein the reflection surface is a polarizing beam splitter, and a half-wave plate is disposed between the reflection surface and the light beam separation surface. 16. A light guide optical system, comprising: a first optical block that transmits image light from the reflection type image display device and enters the projection optical system; and a gap with respect to the first optical block. And a second optical block that reflects illumination light from the light source unit at the air interface facing the gap and causes the illumination light to enter the reflective image display element. The image display device according to claim 3. 17. The image display device according to claim 16, wherein the air interface is a total reflection surface. 18. The light source unit according to claim 1, wherein the light source unit has a light source, and a reflection surface for reflecting illumination light from the light source and making the light incident on the light guide optical system. The image display device as described in the above. 19. The light source unit according to claim 1, wherein the light source unit includes a prism sheet that causes the light from the light source to enter the light guide optical system as substantially parallel light.
The image display device according to any one of the above. 20. The image display device according to claim 1, wherein a polarizing member is disposed between the light source unit and the light guide optical system. 21. The image display device according to claim 1, wherein a polarizing member is disposed between the light guiding optical system and the projection optical system. 22. The image display device according to claim 1, wherein an anti-reflection film is provided on at least one of the optical working surfaces of the light guide optical system. 23. The image display device according to claim 1, wherein a light absorbing layer is provided on at least one of the surfaces of the light guide optical system other than the optically active surface. 24. The image display device according to claim 1, wherein said light guide optical system and said reflection type image display element are integrally fixed by an adhesive. 25. The method according to claim 25, wherein the adhesive has a refractive index substantially equal to a refractive index of light of a material of a cover glass provided in the optical element constituting the light guiding optical system and the reflection type image display element. The image display device according to claim 24, wherein: 26. The projection optical system according to claim 1, wherein the projection optical system has an optical operation surface including at least one reflection surface, and at least one of the optical operation surfaces is a rotationally asymmetric surface. 26. The image display device according to any one of 25. 27. An image display, comprising: the image display device according to claim 1; and an image information output device that supplies image information to the image display device. system. 28. The image display system according to claim 27, wherein the image information output device is a personal computer or a DVD player.