JP2000241750A - Video display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a device which is capable of providing good-quality videos in spite of small-sized and lightweight constitution suitable for a use form by executing the separation of illumination light and reflected light by a translucent reflection element and executing the separation of the light indicating the video included in the reflected light and the unnecessary light by a separating element. SOLUTION: This video display device has a liquid crystal display 11 of a reflection type, a lamp 12, the translucent reflection element (half mirror) 16, observation optical systems 20 and 21 and the separating element (polarizing plate) 22. The half mirror 16 introduces the illumination light from the lamp 12 to the liquid crystal display 11 and introduces the reflected light of the liquid crystal display device 11 to a direction different from the direction heading toward the lamp 12. The observation optical systems 20 and 21 introduce the reflected light of the liquid crystal display device 11 introduced by the half mirror 16 to the observer's eyes and provides the observer with the virtual image of the video displayed on the liquid crystal display device 11. The polarizing plate 22 is arranged in the section behind the half mirror 16 among the optical paths of the reflected light of the liquid crystal display 11 and separates and removes the light exclusive of the light indicating the video from the light introduced to the observer.

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 which is used by being arranged in front of an observer's eyes, and more particularly to an image display device which displays an image by a reflection type liquid crystal display.

[0002]

2. Description of the Related Art There is an image display device which is mounted on a head or held by a hand and used in front of an observer.
It is often used as a means for providing virtual reality with a sense of realism, or as a finder incorporated in a shooting device such as a video camera. Such a video display device,
The light of the displayed image is guided to the eyes of the observer via the observation optical system, and the image is provided to the observer as an enlarged virtual image.

[0003] It is desirable that an image provided to an observer is bright and has high definition, and particularly when providing virtual reality, a wide field of view is desired. On the other hand, it is strongly demanded that the device be small and lightweight due to the usage form of being attached to the head or holding by hand. A liquid crystal display is one of the display elements that can satisfy such requirements, and most of the video display devices used in front of the eyes adopt the liquid crystal display.

A liquid crystal display has a large number of two-dimensionally arranged pixels, and converts polarization of given illumination light in each pixel to bring about a change in intensity distribution of polarized light in the converted light. Modulates light. The polarization conversion of each pixel is individually controlled according to the video signal, and the degree of polarization conversion differs for each pixel. As a result, there is a difference in the amount of polarized light after conversion between pixels, and an image or video having a difference in luminance is provided by guiding the polarized light having the difference in amount to the eyes.

[0005] Liquid crystal displays are roughly classified into a transmission type in which illumination light is applied from the side opposite to the observation side and a reflection type in which illumination light is applied from the same side as the observation side. Reflective LCDs have various advantages over transmissive LCDs. Circuit parts such as TFTs that control each pixel of the liquid crystal display need a certain size, but in a transmissive liquid crystal display, these circuit parts cause the aperture of each pixel to be small. In the reflection type liquid crystal display, since the circuit portion can be disposed on the surface opposite to the observation side, a decrease in the aperture ratio due to the circuit portion is reduced and a bright image can be obtained.

The difference in the aperture ratio between the transmissive liquid crystal display and the reflective liquid crystal display becomes more remarkable as the size of the pixel becomes smaller. Therefore, when the same number of pixels and the same brightness are used, the reflection type liquid crystal display can be formed smaller. On the other hand, when the size of the display is the same, the reflection type liquid crystal display can have a larger number of pixels and can provide an image with higher definition.

In a reflection type liquid crystal display, it is possible in principle to make a liquid crystal layer for performing polarization conversion thinner than a transmission type liquid crystal display. Therefore, the reflection type liquid crystal display can switch the display more quickly.

The use of a reflection type liquid crystal display having such features greatly contributes to achieving a bright and high-definition image required for a video display device used in front of the eyes. In addition, since the size of the display device is reduced, the observation optical system can be reduced, and the device can be easily reduced in size.

[0009]

As described above, it is necessary to provide illumination light to the reflective liquid crystal display from the observation side, and the optical paths of the illumination light and the reflected light overlap. Therefore, it is necessary to separate the unmodulated illumination light from the light source from the reflected light from the modulated liquid crystal display. In addition, since the reflected light includes a polarized light component representing an image and other polarized light components, it is necessary to separate these components. If these separations are not made,
Light directed to the observer's eyes will not be able to represent the image, and if incomplete, will cause ghosting in the image provided.

However, an optical system has not yet been proposed which realizes separation of illumination light and reflected light and separation of required light and unnecessary light in reflected light with a simple configuration. For this reason, the conventional image display device used in front of the eyes only employs a transmissive liquid crystal display device having slightly inferior performance, and the quality of an image to be provided is limited.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to realize a video display device which can provide a better quality video while having a small and lightweight configuration suitable for a use form. I do.

[0012]

In order to achieve the above object, according to the present invention, illumination light is provided to an image display device arranged in front of an observer's eyes to provide a virtual image of a displayed image to the observer. A reflection type liquid crystal display that reflects light and modulates illumination light according to the displayed image, so that part of the reflected light is light representing an image, and a light source unit that supplies illumination light to the liquid crystal display. , The illuminating light from the light source unit is guided to the liquid crystal display, and the reflected light of the liquid crystal display is guided by a semi-transmissive reflective element and a semi-transmissive reflective element that guide the reflected light in a direction different from the direction toward the light source unit. Optical system that guides the reflected light of the liquid crystal display to the observer's eyes to provide a virtual image of the image displayed on the liquid crystal display to the observer, and semi-transmission in the optical path of the reflected light of the liquid crystal display. Placed after the reflective element and observe And a separation device for separating and removing light other than light representing an image from a light guided to the eye.

This image display device displays an image by a reflection type liquid crystal display device having the above-mentioned many features, and can provide high quality images. The separation between the illumination light and the reflected light is performed by a semi-transmissive reflective element.
This semi-transmissive reflective element may transmit the illumination light and guide it to the liquid crystal display, and may reflect the light reflected from the liquid crystal display and guide it to the observation optical system. Then, the light may be guided to the liquid crystal display, and the reflected light from the liquid crystal display may be transmitted to be guided to the observation optical system.

The separation of the light representing the image and the unnecessary light contained in the reflected light is performed by the separation element. The separation element not only removes unnecessary light contained in the reflected light from the liquid crystal display, but also partially mixes the reflected light directly into the reflected light when separating the reflected light from the illuminated light by the semi-transmissive reflective element. In such a case, unnecessary mixed illumination light is also removed. Therefore, light guided to the observer's eyes is only light representing an image, and an image without ghost can be provided.

As the separating element, a polarizing element that transmits only one of two polarized components whose polarization planes are perpendicular can be used. Of the light contained in the reflected light from the liquid crystal display, the light representing the image and the other light have perpendicular polarization planes, so that the polarization element can easily separate them. Also, by setting the liquid crystal display to take out a polarization component having a polarization plane perpendicular to the polarization plane of the illumination light as light representing an image, even when part of the illumination light is mixed into the reflected light, The mixed light can be surely removed.

As the semi-transmissive reflecting element, a polarizing element that transmits one of two polarized components whose polarization planes are perpendicular to each other and reflects the other may be used as a separating element. The number of optical elements provided in the apparatus can be reduced by one.
In this case, a polarization component having a polarization plane perpendicular to the polarization plane of the illumination light will be extracted as light representing an image, and the semi-transmissive reflection surface will extract the image contained in the reflected light from the liquid crystal display. It can be set so as to reflect or transmit all the light to be represented, and to transmit or reflect all illumination light having a polarization plane perpendicular to the polarization plane of the light. Therefore, there is no loss in the transflective element for translucent light that represents an image or light that represents an image.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the video display device of the present invention will be described with reference to the drawings. In FIG.
1 shows a configuration of an optical system of a video display device 1 according to a first embodiment. The image display device 1 includes a reflective liquid crystal display 11,
Lamp 12, reflector 13, polarizing plate 14, prism 1
5 and another polarizing plate 22.

The lamp 12, the reflector 13, and the polarizing plate 14 are arranged so as to face the display surface of the liquid crystal display 11, and constitute a light source for supplying illumination light to the liquid crystal display 11. The lamp 12 emits light whose polarization plane is disordered, and the reflector 13 reflects the light emitted by the lamp 12 into a substantially parallel light flux. The polarizing plate 14 is a light source that emits light from the lamp 12.
Only the polarization component Lp1 having a constant polarization plane is transmitted.

The prism 15 is formed by joining two prisms 15a and 15b made of polymethyl methacrylate (PMMA), and is disposed between the liquid crystal display 11 and the polarizing plate 14. A semi-transmissive reflective film that transmits approximately one half of incident light and reflects approximately one half of the incident light is provided on a joint surface between the prisms 15a and 15b. I have. The prism 15 is arranged such that the half mirror 16 has a 45 ° inclination with respect to a straight line passing through the center of the display surface of the liquid crystal display 11 and perpendicular to the display surface.

An aperture 18 is provided in contact with the surface 17 of the prism 15a close to the polarizing plate 14.
Is opposed to the prism 15 via the aperture of the diaphragm 18. The aperture 18 prevents external light from being mixed into the illumination light of the liquid crystal display 11.

A prism 15b close to the liquid crystal display 11
Is a convex surface. The surface 19 acts as a condenser lens for the illumination light, and makes the angle of the illumination light with respect to the display surface of the liquid crystal display 11 closer to the vertical. Prism 1
The surface 20 next to the surface 19 of 5b is also a convex surface, and a total reflection film is formed on this surface 20. Therefore, the surface 20 of the prism 15b becomes a total reflection concave mirror with respect to the light from the half mirror 16 side, and converges the reflected light.

Prism 15a facing concave mirror 20
The surface 21 is also convex, and acts as a convex lens for transmitted light. The polarizing plate 22 is arranged perpendicular to the display surface of the liquid crystal display 11 and close to the surface 21. The polarizing plate 22 is set so as to transmit only a polarization component Lp2 having a polarization plane perpendicular to the polarization plane of the polarization component Lp1 transmitted by the deflection plate 14.

The liquid crystal display 11 is driven by a drive circuit (not shown). The liquid crystal display 11 reflects the provided illumination light, modulates the illumination light according to the displayed image, and rotates a part of the polarization plane of the reflected light by 90 °. In the image display device 1, the driving of the liquid crystal display 11 is controlled so that the polarization component whose polarization plane is rotated by 90 ° becomes light representing an image. Therefore, of the light included in the reflected light of the liquid crystal display 11, the light representing the image is the polarization component Lp of the polarization plane perpendicular to the polarization plane of the polarization component Lp 1 transmitted by the deflecting plate 14.
It becomes 2.

The image display device 1 is used in such a manner that a predetermined distance is provided from the pupil EP of the observer to the polarizing plate 22 in front of the observer's eyes. The light emitted by the lamp 12 is
After being converted into only the polarization component Lp <b> 1 by the polarizing plate 14, the light passes through the surface 17 and enters the half mirror 16. Half of the light incident on the half mirror 16 passes through the half mirror 16 and also passes through the convex surface 19 to illuminate the liquid crystal display 11.

A part of the light modulated and reflected by the liquid crystal display 11 becomes a polarization component Lp2 representing an image, and the rest remains the polarization component Lp1. Polarization components Lp1, Lp2
The reflected light from the liquid crystal display 11 containing the light passes through the convex surface 19, enters the half mirror 16 again, and is half reflected. The light reflected by the half mirror 16 is incident on the concave mirror 20 and is totally reflected and converged, and is incident on the half mirror 16 again. Half of this light passes through the half mirror 16, passes through the convex surface 21, and is incident on the polarizing plate 22 while being further converged.

Of the light incident on the polarizing plate 22, the polarized light component Lp1 is cut off, and only the polarized light component Lp2 representing an image passes through the polarizing plate 22 and is incident on the pupil EP of the observer. Thus, the observer is provided with an enlarged virtual image of the image displayed on the liquid crystal display 11. The surfaces 17 and 19 of the prism 15 constitute an illumination optical system for guiding illumination light from the light source unit to the liquid crystal display 11, and the surfaces 20 and 21 of the prism 15 observe reflected light from the liquid crystal display 11. An observation optical system is provided for guiding an observer's eyes to provide an enlarged virtual image of a displayed image. The optical path of the illumination light and the optical path of the reflected light overlap between the half mirror 16 and the liquid crystal display 11, and the illumination light and the reflected light are separated by the half mirror 16.

Half of the illumination light from the light source is reflected by the half mirror 16 and is mixed with the reflected light from the liquid crystal display 11. However, since the illumination light is the polarization component Lp1, it is completely blocked by the polarizing plate 22 and does not enter the pupil EP. Therefore, the image provided to the observer is clear without ghost.

The optical system of the image display device 1 is a coaxial system in which all elements are rotationally symmetric with respect to the optical axis. Tables 1 and 2 show specific values of the setting examples of the optical system. In Table 1, parameters K, A, B, C, and D relating to a rotationally symmetric aspherical surface are defined by Expression 1 when an intersection between each surface and its optical axis is set as the origin and the optical axis is set as the Z axis. This defines the sag Z in the Z-axis direction (unit: mm). Table 2 shows the relative positional relationship of each surface. Here, the center of the pupil EP is the origin, and the axis perpendicular to the pupil plane (first plane) is the Z axis. XSC, YSC, and ZSC represent the X, Y, and Z coordinates (unit: mm) of the intersection of each surface and its optical axis, and include ASC, BS
C and CSC represent rotation angles (unit ゜) of each plane from the pupil plane with respect to the X axis, the Y axis, and the Z axis.

Z = ch · h ² / [1+ ｛1- (1 + K)
· C ² · h ² ｝ ^1/2 ] + A · h ⁴ + B · h ⁶ + Ch · h ⁸
+ D · h ¹⁰ where c = 1 / r and h = (X ² + Y ² ) ^1/2 .

[0030]

[Table 1]

[0031]

[Table 2]

In the image display device 1, the image displayed on the liquid crystal display 11 is mainly a virtual image enlarged by the concave mirror 20, and chromatic aberration hardly occurs. Further, by providing the observation optical system with the concave mirror 20, the optical path of the reflected light of the liquid crystal display 11 can be changed by the half mirror 1
6 and the concave mirror 20 can be overlapped, and the overall configuration of the optical system is reduced in size. This configuration can be adopted because the polarizing plate 22 is provided to allow the illumination light to be mixed with the reflected light.

The image display apparatus 1 having the above-described structure can be provided as a head-mounted display apparatus (HMD) or a hand-held binocular type apparatus by providing two sets, and a video camera for converting a captured image into an electric signal. It can also be used as a finder by incorporating it into a photographing device such as.

Here, the illumination light is guided to the liquid crystal display 11 through the half mirror 16, and is transmitted to the liquid crystal display 11.
Is reflected by the half mirror 16 and guided to the observation optical system. Conversely, the illuminating light is reflected by the half mirror 16 and guided to the liquid crystal display 11, and transmitted through the half mirror 16 to display the liquid crystal. The reflected light from the vessel 11 may be guided to the observation optical system. In that case, for example, the concave mirror 20
May be provided on the prism 15a so as to face the liquid crystal display 11, and the diaphragm 18 and the light source may be provided on the prism 15b so as to face the polarizing plate 22.

Further, instead of using the concave mirror 20, an observation optical system can be constituted only by a lens.
For example, the surface 20 of the prism 15b is made not to be totally reflective but to be totally transmissive so that the surface has an appropriate positive power, and the polarizing plate 22 is arranged close to the surface. Face 20
May be a plane having total transmittance, and a lens having a positive power may be separately provided.

FIG. 2 shows the configuration of the optical system of the video display device 2 according to the second embodiment. The image display device 2 includes a reflective liquid crystal display 31, a lamp 32, a reflector 33, a polarizing plate 34, a prism 35, and a plate element 44.

The lamp 32, the reflector 33, and the polarizing plate 34 are arranged so as to face the display surface of the liquid crystal display 31, and constitute a light source unit for supplying illumination light to the liquid crystal display 31. The lamp 32 emits light whose polarization plane is disordered, and the reflector 33 reflects the light emitted by the lamp 12. Polarizing plate 34
Transmits only the polarization component Lp1 having a constant polarization plane among the light emitted from the lamp 32.

The prism 35 is constituted by joining two prisms 35 a and 35 b made of PMMA, and is disposed between the liquid crystal display 31 and the polarizing plate 34. A semi-transmissive reflective film that transmits P-polarized light and reflects S-polarized light is provided on the joint surface between the prisms 35a and 35b. Prism 35
Is disposed such that the polarization splitting mirror 36 has a 45 ° inclination with respect to a straight line passing through the center of the display surface of the liquid crystal display 31 and perpendicular to the display surface.

On the surface 37 of the prism 35a close to the polarizing plate 34, a stop 38 for blocking light from the outside is provided. The polarizing plate 34 faces the prism 35 through the opening of the stop 38. . The surface 39 of the prism 35b close to the liquid crystal display 31 has a convex surface so as to act as a condenser lens for illumination light. Prism 3
The surface 40 next to the surface 39 of 5b is a flat surface,
A λ phase plate 43 is provided. The surface 41 of the prism 35a facing the surface 40 is also a flat surface.

The plate element 44 has the same PM as the prism 35.
It is made of MA, and is arranged close to the surface 40 of the prism 35b provided with the λλ phase plate 43. The surface 45 of the plate element 44 on the １ ／ λ phase plate 43 side is a convex surface, and acts as a convex lens for light. The surface 46 opposite to the surface 45 is also a convex surface, and a total reflection film is formed on the surface 46. Therefore, the surface 46 is ４λ
It becomes a total reflection concave mirror for the light from the phase plate 43 side, and converges the reflected light.

The polarizing plate 34 is set so that the transmitted polarized light component Lp 1 becomes P-polarized light with respect to the polarized light separating mirror 36. Further, the liquid crystal display 31 is controlled such that the polarization component whose polarization plane is rotated by 90 ° becomes light representing an image.

The light emitted from the lamp 32 is converted into only the polarized light component Lp1 by the polarizing plate 34, and then passes through the surface 37 to enter the polarized light separating mirror 36. All of this light passes through the polarization separating mirror 36 and also passes through the convex surface 39 to illuminate the liquid crystal display 31.

A part of the light modulated and reflected by the liquid crystal display 31 becomes a polarization component Lp2 representing an image, and the rest remains the polarization component Lp1. Polarization components Lp1, Lp2
The reflected light from the liquid crystal display 31 including the reflected light passes through the convex surface 39 and re-enters the polarization splitting mirror 36, where the polarization component Lp
1 transmits this. The polarization component Lp2 is S-polarized with respect to the polarization split mirror 36 and is reflected.

The light reflected by the polarization splitting mirror 36 is incident on the plate-like element 44 and is reflected by the concave mirror 46, and is incident on the polarization splitting mirror 36 again while converging. During this time, the light is transmitted twice through the λλ phase plate 43, the polarization plane is rotated by 90 °, and becomes the P-polarized light again with respect to the polarization separation mirror 36. This light passes through the polarization splitting mirror 36 and also passes through the surface 41, and the pupil EP of the observer
Incident on. Thus, the observer is provided with an enlarged virtual image of the image displayed on the liquid crystal display 31.

In the image display device 2 of the present embodiment, both surfaces 45 and 46 of the plate-like element 44 constitute an observation optical system. The polarization separating mirror 36 separates the illumination light from the light source unit and the reflected light from the liquid crystal display 31 and also separates the light representing the image contained in the reflected light from the liquid crystal display 31 from the other light. Do. Since there is no illumination light reflected by the polarization separation mirror 36 or light representing an image transmitted through the polarization separation mirror 36, the image display device 2 can use light without loss and provide an extremely bright image. Can be.

Here, the illumination light is transmitted through the polarization splitting mirror 36 and guided to the liquid crystal display 31, and
1 is reflected by the polarization separation mirror 36 and guided to the observation optical system. Conversely, the illumination light is reflected by the polarization separation mirror 3.
The light is reflected by 6 and led to the liquid crystal display 31, where the polarization splitting mirror 3
6, the reflected light from the liquid crystal display 31 may be guided to the observation optical system. In that case, for example, 1/4
The λ phase plate 43 is provided on the prism 35 a so as to face the liquid crystal display 31, a concave mirror 46 is provided here, and the stop 38 and the light source unit are provided on the prism 35 b so as to face the pupil EP, and polarization separation is performed. The mirror 36 may be set to reflect P-polarized light and transmit S-polarized light.

Further, instead of using the concave mirror 46, the observation optical system can be constituted by only the lens.
For example, the surface 46 of the plate-shaped element 44 may be made to be totally transmissive rather than totally reflective, and the surface may have an appropriate positive power. In that case, it is not necessary to provide the λλ phase plate 43. Also, a polarization component L representing an image in the illumination light from the light source unit.
Even if p2 is included, since the light is totally reflected by the polarization split mirror 36 on the opposite side of the pupil EP, the polarizing plate 44 is not required.

[0048]

According to the image display apparatus of the present invention, it is possible to display a bright and high-definition image by the reflection type liquid crystal display, and to guide the light to the eyes of the observer without ghost.
It can provide excellent quality pictures. In addition, the transflective element for separating the illumination light from the reflected light and the separating element for extracting the light representing the image from the reflected light are simple, and the position of the separating element is restricted. Since there are few, the overall configuration is simplified, resulting in a small and lightweight device.

Further, since all the light other than the light representing an image is removed by the separating element, a part of the illuminating light may be mixed with the reflected light when the illuminating light and the reflected light are separated by the semi-transmissive reflecting element. Permissible. Therefore, the relative arrangement positions of the light source unit, the liquid crystal display, and the observation optical system and the degree of freedom in the configuration of the observation optical system are increased, and the device can be further reduced in size and weight.

In a configuration in which a polarizing element that transmits only one of two polarized components having a perpendicular polarization plane is used as the separating element, light representing an image can be easily extracted from the reflected light. In addition, by extracting a polarization component having a polarization plane perpendicular to the polarization plane of the illumination light as light representing an image, even when a part of the illumination light is mixed into the reflected light, ghost is reliably generated. Is prevented.

As a semi-transmissive reflecting element, a polarizing element that transmits one of two polarized components whose polarization planes are perpendicular and reflects the other is used, and this also serves as a separating element. And the apparatus becomes simpler. In addition, the semi-transmissive reflecting surface reflects or transmits all the light representing the image contained in the reflected light from the liquid crystal display, and transmits all the illumination light having a polarization plane perpendicular to the polarization plane of this light. As the setting for reflection or reflection, it is possible to eliminate loss of light in the semi-transmissive reflection element, and to provide an extremely bright image.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an optical system of a video display device according to a first embodiment.

FIG. 2 is a diagram illustrating a configuration of an optical system of a video display device according to a second embodiment.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 image display device 11 reflective liquid crystal display 12 lamp (light source unit) 14 polarizing plate 15 prism 16 half mirror (semi-transmissive reflective element) 20 total reflection concave mirror (observation optical system) 21 convex lens surface (observation optical system) 22 Polarizing plate (separating element) 2 Image display device 31 Reflective liquid crystal display 32 Lamp (light source) 34 Polarizing plate 35 Prism 36 Polarization separating mirror (semi-transmissive reflecting element, separating element) 43 1 / 4λ phase plate 45 Convex lens surface (Observation optical system) 46 Total reflection concave mirror (Observation optical system)

Claims (3)

[Claims] 1. An image display device arranged in front of an observer's eyes to provide a virtual image of a displayed image to an observer, wherein the reflected illumination light is reflected and the illumination light is modulated by the displayed image. A reflection-type liquid crystal display that uses a part of the reflected light as light representing an image; a light source unit that supplies illumination light to be provided to the liquid crystal display; and an illumination light from the light source unit that is guided to the liquid crystal display. And a semi-transmissive reflective element for guiding the reflected light of the liquid crystal display in a direction different from the direction toward the light source unit; and observing the reflected light of the liquid crystal display guided by the semi-transmissive reflective element. An observation optical system that guides the observer's eyes to provide a virtual image of an image displayed on the liquid crystal display to an observer, and the transflective element and the subsequent elements in the optical path of the reflected light of the liquid crystal display. Placed on the site Image display device characterized by comprising an optical separation device for separating and removing the light other than the light representing the image to be guided to. 2. The image display device according to claim 1, wherein the separation element is a polarization element that transmits only one of two polarization components whose polarization planes are perpendicular to each other. 3. The polarizing element according to claim 1, wherein the semi-transmissive reflecting element is a polarizing element that transmits one of two polarized light components whose polarization planes are perpendicular and reflects the other, and also functions as the separating element. 3. The video display device according to 1.