JP3419766B2 - Apparatus that can switch between image display state and mirror state, and equipment equipped with this - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device having a mirror function capable of switching a display screen to a mirror and a device having the display device, or a mirror having an image display function capable of switching the mirror to an image display screen. The present invention relates to a device equipped with this.

[0002]

2. Description of the Related Art As a display device (or a mirror having a display function) that can be switched to a mirror state that reflects external light, for example, JP-A-11-15392 and JP-A-11-291 are available.
As described in Japanese Patent No. 817 or the like, there is known a display device in which a half mirror material is arranged in front of an image display member such as a liquid crystal display device. In these display devices, when the illumination device is turned off or when the image is displayed darkly, the external light reflected by the half mirror material becomes larger than the image light that passes through the half mirror material, and thus becomes a mirror state. On the other hand, when the illuminating device is turned on or when the image is displayed brightly, the image light transmitted through the half mirror material is larger than the external light reflected by the half mirror material, and thus the image display state is set. That is, in these display devices, the same observation surface can be switched between the mirror state and the image display state by switching the brightness of the image display member on the back surface of the half mirror material.

International publication number WO99 / 04315
The re-publication publication discloses a liquid crystal display device capable of switching between a shutter open state in which an image display is observed and a shutter closed state in which an image display is not observed. According to this publication, when the shutter is closed, the external light is reflected to be "metal-like".

The liquid crystal display device of the republished publication of WO99 / 04315 has two liquid crystal display panels in which a liquid crystal layer is sealed in a gap between a pair of substrates provided with electrodes, and the two liquid crystal display panels are stacked. Polarizing plates are arranged on the upper surface, the lower surface and three places between the two liquid crystal display panels. Among these polarizing plates, as a polarizing plate arranged between the liquid crystal display panels, a reflection type polarizing plate which transmits predetermined linearly polarized light and reflects linearly polarized light whose polarization axis is orthogonal to this is used. The transmission polarization axes of the reflective polarizing plates are
The transmission polarization axis of the polarizing plate on the upper surface of the liquid crystal display panel is parallel. Further, in the liquid crystal display panel on the upper side (observer side), twisted nematic liquid crystal is used as the liquid crystal. With such a configuration, when the voltage applied to the liquid crystal layer of the upper liquid crystal display panel is small, the light transmitted through the upper polarizing plate has a polarization direction of 9 when transmitted through the liquid crystal layer.
Since it rotates to 0 ° to reach the reflective polarizing plate, it is strongly reflected by the reflective characteristics of the reflective polarizing plate. As a result, the shutter is closed in "metal tone". On the other hand, when the voltage applied to the liquid crystal layer of the upper liquid crystal display panel is large, the upper polarizing plate, the upper liquid crystal display panel and the reflective polarizing plate are effectively transparent, and the lower liquid crystal display The shutter is opened so that the image display on the panel can be observed. That is, it is possible to switch between the shutter closed state in which external light is reflected and presents a "metal tone" and the shutter open state in which the display of the lower liquid crystal display panel is observed by the printing voltage applied to the upper liquid crystal display panel. .

[0005]

The above-mentioned conventional display device can be switched to a mirror-like state that reflects external light. In this mirror-like state, a person reflects his or her face or figure. It is not sufficient for use as a viewing mirror. This will be specifically described below.

Since the display devices of the above-mentioned JP-A-11-15392 and JP-A-11-291817 use half mirrors, the brightness of the mirror state that reflects external light depends on the reflectance of the half mirrors. Dependent. For this reason, it is necessary to increase the reflectance of the half mirror in order to make it a bright mirror that can be used by people as a mirror that reflects their face or figure.
However, if the reflectance of the half mirror is increased, the amount of light of the image is reduced by the amount of light reflected by the half mirror material in the image display state, and the displayed image becomes dark. That is, since there is a trade-off relationship between the brightness of the image in the image display state and the brightness of the mirror in the mirror state, it is difficult to achieve both a bright image display and a bright mirror. For this reason, it is difficult to increase the brightness of the mirror state of the display device using the half mirror to the extent that it can be used as a mirror for a person to observe his / her face or figure.

Further, in a display device using such a half mirror, when used in a bright environment, a part of external light is reflected by the half mirror even in an image display state. Therefore, in the image display state, the image quality is deteriorated, such as the reflection of external light and the reduction of the contrast ratio of the image due to the reflection of external light.

Further, the above-mentioned international publication number WO99 / 04
In the display device of the republication bulletin of 315, the function of reflecting external light is
The following problems occur when a person tries to function as a mirror that reflects and observes his or her face or figure.

In this display device, when the voltage applied to the liquid crystal layer of the upper (observer side) liquid crystal panel of the two liquid crystal panels is small, the "metal-like" shutter is closed. At this time, light incident from the outside passes through the polarizing plate on the upper surface, passes through the liquid crystal layer of the upper liquid crystal panel, is reflected by the reflective polarizing plate, and returns to the outside again. This gives a mirror-like reflection. On the other hand, of the image display light emitted from the lower liquid crystal panel, the light whose polarization state is controlled as dark display light is because the transmission polarization axis and the polarization axis of the reflective polarizing plate are orthogonal to each other. , Is reflected by this reflective polarizing plate and is not emitted to the outside. However, in reality,
Since there is no perfect reflective polarizing plate having a reflectance of 100% in the direction orthogonal to the transmission polarization axis, some light in the dark display portion passes through the reflective polarizing plate. The dark display light that has passed through the reflective polarizing plate passes through the liquid crystal layer of the upper liquid crystal panel, so that the polarization axis matches the transmission polarization axis of the upper polarizing plate. It That is, in the mirror state with the shutter closed, light leaks from the dark display portion of the image to the outside.

Of the image display light emitted from the lower liquid crystal panel, the light whose polarization state is controlled as the bright display light has a polarization axis parallel to the transmission polarization axis of the reflection type polarizing plate. , And then passes through the liquid crystal layer of the upper liquid crystal panel. At that time, since the polarization axis rotates 90 degrees, the polarization axis is orthogonal to the upper polarizing plate and is absorbed by the upper polarizing plate. As is generally known, when light is passed through a liquid crystal layer that is twisted continuously in the layer thickness direction to emit light, depending on the tilt of the liquid crystal molecule in the layer thickness direction and the twist state, Since the polarization state of the light emitted in the oblique direction of the liquid crystal layer is different, the light emitted in the oblique direction includes a polarization component parallel to the transmission polarization axis of the polarizing plate on the upper surface. Therefore, a large amount of light leaks from an oblique direction rather than the front direction of the display device, and the light is visually recognized by an observer.

The inventors of the present invention have made international publication number WO99 / 04
FIG. 44 shows the result of actually producing a display device substantially the same as the display device of the republication publication 315 and measuring the leakage of light in the shutter closed state. The graph of FIG. 44 shows that the image is displayed on the lower liquid crystal panel so that a brightness of 450 cd / m ² can be obtained in the bright display section when the image is displayed on the display device with the shutter open. This is data obtained by measuring light leakage from the front surface of the display device with the panel closed. The horizontal axis of FIG. 44 represents the position on the display unit of the display device, and the vertical axis represents the luminance value in the front direction.

As shown in FIG. 44, light leakage in the front direction of the dark display portion has a luminance value of 24 to 28 cd / m ² , and light leakage in the front direction of the bright display portion has a luminance value of 4 to 5 cd / m ^2. Met. Therefore,
The light leakage in the front direction was about 7 times larger in the dark display area than in the bright display area. In addition, light leakage in the dark display area was nonuniform with respect to the position, and color unevenness was also observed. The brightness value of 4 to 5 cd / m ² is a value that can be sufficiently visually recognized in a dim environment. Further, when observed from an oblique direction, light leakage of ⁴ to 5 cd / m ² or more was observed from the bright display portion depending on the direction. Thus, when the shutter closed state of the conventional display device is made to function as a mirror, the contrast ratio of the reflected image is significantly reduced due to light leakage. For this reason, it is not enough as a mirror that reflects the human face or figure.

As the reflective polarizing plate, for example, a birefringent reflective polarizing film in which a plurality of different birefringent polymer films disclosed in International Publication No. WO95 / 27919 are alternately laminated is used. be able to. Such a reflective polarizing plate is usually arranged between the polarizing plate arranged on the back surface side of the liquid crystal element and the illuminating device (backlight), when it is used for the purpose of improving the utilization efficiency of illumination light. An extremely high effect can be obtained. However, in order to realize the mirror performance that is the object of the present invention, the leakage of light with respect to a predetermined polarized light becomes a serious problem, and therefore such a reflective polarizing plate alone cannot provide sufficient mirror performance.

The present invention provides a device capable of switching between a state in which a high-quality image is displayed and a mirror state in which a reflected image that is easy to see and is suitable for a person to observe by observing his / her face or figure is obtained. The purpose is to

[0015]

In order to achieve the above object, according to the present invention, there is provided a device capable of switching between an image display state and a mirror state having the following configuration.

That is, the image display section for emitting the image light for displaying a desired image, the image transmission state for transmitting the image light and the external light, which are arranged to be superposed on the image display section, are reflected. A mirror function part capable of switching to a mirror state, the mirror function part being arranged in order from the image display part side, a reflection type polarization selecting means, a transmission polarization axis varying means, and an absorption type polarization selecting means. Means for transmitting the first polarized light having a predetermined polarization axis,
Of the second polarized light whose polarization axis intersects with the polarized light of, and the transmission polarization axis varying means changes the incident first polarized light to the second polarized light and transmits the polarized light. It is possible to switch to a transmission state without changing the polarization axis, and the absorptive polarization selection means transmits one of the first polarized light and the second polarized light and absorbs the other, and the image display unit. Is equipped with an image light polarization selecting means that transmits the first polarized light and absorbs the second polarized light, and emits the first polarized light that has passed through the image light polarization selecting means as the image light. The device is capable of switching between an image display state and a mirror state.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION In this embodiment, an apparatus capable of switching between an image display state and a mirror state (that is, a display device with a mirror function or a mirror with a display function) is provided. In the mirror state, this device can prevent light leakage of image display light and obtain a bright reflected image with a high contrast ratio. Therefore, the device of the present embodiment is suitable for a person to project and observe his / her face or figure in the mirror state. It is generally considered that the appearance of a human face depends on physical quantities such as the size of the part, the brightness value, and the contrast ratio (brightness contrast). The larger the contrast ratio (brightness contrast), the easier it is to see. It has been confirmed by evaluation experiments that the evaluation is high (Shino Okuda, Ryuji Sato: Basic study on construction of evaluation method for human face appearance, Journal of Lighting Society, Vol. 84, No. 11, pp809-814) . Further, in the image display state, the apparatus of the present embodiment can obtain a bright image with little deterioration of image quality such as reflection of external light and deterioration of contrast ratio even in a bright environment.

A display device with a function of switching to a mirror state according to an embodiment of the present invention will be described below with reference to FIGS.

First, FIG. 1 and FIG. 2 show the basic configuration and operation of the display device with a function for switching to the mirror state according to the first embodiment.
Will be explained.

As shown in FIG. 1, the display device of the first embodiment has an image display section 1000, a reflective polarization selection member 300, a transmission polarization axis variable section 400, and an absorption polarization section, which are arranged in order. And a selection member 500. Image display section 1
000 includes an absorption-type polarization selection member 208 that transmits a linear polarization component in a predetermined direction and absorbs a linear polarization component in a direction orthogonal to the predetermined direction.
Are arranged on the reflective polarization selection member 300 side. In the present embodiment, the image display unit 1000 includes a lighting device,
It includes a liquid crystal layer and two absorption polarization selection members sandwiching the liquid crystal layer. Of the two absorption type polarization selection members, the one on the output side is
It is an absorption type polarization selection member 208. The voltage applied to the liquid crystal layer is changed between the bright display region and the dark display region, linearly polarized light that passes through the absorption polarization selection member 208 is emitted from the bright display region, and the absorption polarization selection member 208 is output in the dark display region.
Absorbs light and does not emit light. Thereby, the image is displayed. Therefore, the image display unit 1000
The image light (bright display light) emitted from is linearly polarized light having a polarization axis that matches the transmission polarization axis of the absorption-type polarization selection member 208. Hereinafter, linearly polarized light having a polarization axis in the same direction as the polarization axis of image light will be referred to as “first linearly polarized light”. Further, the linearly polarized light in the direction in which the polarization axis is orthogonal to the first linearly polarized light is referred to as "second linearly polarized light".

The reflection type polarization selecting member 300 is a member which transmits a linearly polarized light component in a predetermined direction and reflects a linearly polarized light component orthogonal to the linearly polarized light component. Here, the reflective polarization selection member 300 is arranged so that the first linearly polarized light component is transmitted and the second linearly polarized light component is reflected.

The transmission polarization axis changing unit 400 changes the polarization axis of incident linearly polarized light when it is transmitted,
It is an element having a structure in which a state in which the polarization axis is not changed can be selected by electrical switching. In the present embodiment, the transmission polarization axis varying unit 400 includes a liquid crystal layer 407,
A transparent electrode 403 for applying a voltage to the liquid crystal layer 407,
And a liquid crystal element including 406. Transparent electrode 403
Is a changeover switch 8 for switching the voltage on and off.
13 is connected. When the voltage applied to the liquid crystal layer 407 is turned off by the changeover switch 813, the liquid crystal layer 407 is in a state where the polarization axis of the incident linearly polarized light is changed, and when the voltage is turned on, the polarization axis is not changed. Become. In this embodiment mode, the liquid crystal layer 407 is used.
Indicates that the long axis of the liquid crystal molecule 407a is continuously 90 ° between the transparent electrode 403 and the transparent electrode 406 when the voltage is off.
It is a so-called twisted nematic (TN) type liquid crystal that is configured to be twisted. The alignment direction of the liquid crystal layer 407 is
The direction of changing the first linearly polarized light incident from the reflective polarization selection member 300 side to the second linearly polarized light is set. On the other hand, when the voltage is on, the liquid crystal molecules 407a of the liquid crystal layer 407
2 is in a state of standing vertically to the transparent electrodes 403 and 406 as shown in FIG. 2, and is in a state of not changing the polarization axis of incident light.

The absorptive polarization selection member 500 is a member which transmits a linearly polarized light component in a predetermined direction and absorbs a linearly polarized light component in a direction orthogonal thereto. Here, the absorptive polarization selection member 500 is arranged so as to absorb the first linearly polarized light component and transmit the second linearly polarized light component of the incident light.

It should be noted that the observer is to observe the absorption type polarization selecting member 500.
The display device is observed from the side (the left side of the paper surface in FIG. 1).

Next, the operation of the display device according to the first embodiment will be described with reference to FIGS.

When the display device of the present embodiment is used in an image display state, as shown in FIG.
13 is turned off, and the liquid crystal layer 4 of the transmission polarization axis varying unit 400 is turned on.
The liquid crystal molecule 407a of No. 07 is set to be twisted by 90 °. In this state, image light (bright display light) 3001 of a desired display is emitted from the image display unit 1000. Image light 30
01 is the absorption type polarization selection member 20 of the image display unit 1000.
Since the light has passed through 8, it is the first linearly polarized light. Therefore, the polarization axis of the image light 3001 matches the transmission polarization axis of the reflection type polarization selection member 300, passes through the reflection type polarization selection member 300, and enters the transmission polarization axis variable unit 400. As described above, since the liquid crystal layer 407 of the transmission polarization axis varying unit 400 is set to the off state, the incident first linearly polarized image light 3001 is the liquid crystal molecules 407a.
The polarization axis of the light is rotated along the twist of the light to be emitted as the second linearly polarized light. Image light 30 that has become the second linearly polarized light
01 has a polarization axis that coincides with the transmission polarization axis of the absorptive polarization selection member 500, so that the light is transmitted through this axis and is observed by an observer.

On the other hand, the external light 3002 incident on the display device from the viewer side in the image display state is unpolarized light, but when transmitted through the absorption type polarization selection member 500, the first linearly polarized light component is absorbed. , The second linearly polarized light component is transmitted.
The external light 3002 of the second linearly polarized light that has passed through the absorption polarization selection member 500 changes from the second linearly polarized light to the first linearly polarized light when it passes through the transmission polarization axis variable unit 400. As a result, the polarization axis coincides with the transmission polarization axis of the reflection-type polarization selection member 300, so that the light is transmitted without being reflected by the reflection-type polarization selection member and enters the image display unit 1000. The incident linearly polarized external light 3002 has a polarization axis that matches the transmission polarization axis of the absorption-type polarization selection member 208.
The image display unit 100 is transmitted through the absorption type polarization selection member 208.
It is incident on the liquid crystal layer of 0. At this time, the light that has entered the dark display region is absorbed by the absorption polarization selection member that is arranged closer to the lighting device than the liquid crystal layer. Therefore, it does not return to the observer side. In addition, the light incident on the bright display area is
The absorption type polarization selecting member on the light source side is also transmitted to reach the illumination device. Although a part of the light reaching the lighting device is reflected by this, the reflected light is substantially the same as the lighting light and becomes a part of the lighting light. Don't That is, in the display device of the present embodiment,
Even when external light enters in the image display state, there is almost no reflection of external light that deteriorates the image quality.

As described above, the display device of the present embodiment is
In the image display state, a bright image can be obtained because the image light 3001 is directed toward the observer with almost no loss. On the other hand, since the external light 3002 is hardly reflected by the display device, there is almost no deterioration in image quality due to reflection of external light such as glare and reduction in contrast ratio.

Next, a case where the display device of the present embodiment is used by switching it to a mirror state will be described. In this case, as shown in FIG. 2, the changeover switch 813 is turned on to set the liquid crystal molecules 407a of the liquid crystal layer 407 of the transmission polarization axis varying unit 400 in an upright state.

At this time, the external light 3002 traveling from the viewer side to the display device is unpolarized, but when transmitted through the absorption type polarization selection member 500, the first linearly polarized light component is absorbed,
Only the second linearly polarized light component is transmitted, and the transmission polarization axis variable unit 4
Incident on 00. The transmission polarization axis varying unit 400 includes the liquid crystal layer 4
Since the liquid crystal molecule 407a of No. 07 is in a standing state, the incident external light 3002 passes through the transmission polarization axis variable unit 400 as the second linearly polarized light without changing the polarization state, and is transmitted to the reflective polarization selection member 300. Reach Reflective polarization selection member 30
Since the reflection polarization axis of 0 coincides with the polarization axis of the second linearly polarized light, the external light 3002 is reflected by the reflective polarization selection member 300. The external light 3002 reflected by the reflection-type polarization selection member 300 again enters the transmission polarization axis variable unit 400, passes through the second linearly polarized light as it is, and is emitted, and further passes through the absorption-type polarization selection member 400. To the observer. As a result, a reflected image of the external light 3002 is obtained and a mirror state is realized.

In this mirror state, the image display unit 1000
Since the image light (bright display light) 3001 emitted from is the first linearly polarized light that has passed through the absorption polarization selection member 208, it passes through the reflection polarization selection member 300 and enters the transmission polarization axis variable unit 400. To do. Since the transmission polarization axis variable unit 400 is in the ON state, the polarization state of the image light 3001 does not change and the first linearly polarized light is transmitted therethrough and is incident on the absorption type polarization selection member 500. Since the first linearly polarized light coincides with the absorption polarization axis of the absorption polarization selection member 500, it is absorbed by the absorption polarization selection member 500 and is not observed by the observer.

That is, in the case of the mirror state, the light from the image display member does not reach the observer, while the external light 3002 incident on the display device from the surroundings is ideally half of the unpolarized light. Since the light is reflected by the reflective polarization selection member 300 and is directed toward the viewer side, it functions as a bright mirror.

In the mirror state, the display device of the present embodiment can greatly reduce light leakage as compared with the display device of the republication publication of International Publication No. WO99 / 04315. In International Publication Number WO99 / 04315,
Light leakage from the dark display portion due to the reflection performance of the reflection type polarizing plate in the mirror state was a problem, but in the display device of the present embodiment, the image display unit 1000 includes the absorption type polarization selection member 208. Since the illumination light in the dark display area is absorbed, the light does not reach the reflective polarization selection member 300 in the dark display area. Therefore, regardless of the performance of the reflective polarization selection member 300, light leakage from the dark display region is hardly observed.

Further, the display device of the present embodiment has a structure in which the transmission polarization axis variable section 400 is turned on to stand up the liquid crystal molecules 407a in the mirror state. In the nematic liquid crystal, in general, the deviation of the polarization axis of light emitted obliquely is smaller when the voltage-on liquid crystal molecules are erected than when the voltage-off liquid crystal molecules are twisted. Therefore, in the display device of this embodiment, the image light (bright display light) 3001 is slanted in the mirror state in the mirror state, as compared with the structure described in the related art in which the voltage is turned off in the mirror state. The effect of less light leakage is also obtained.

The leakage of light from the image display unit 1000 in the mirror state will be specifically described with reference to the graphs of FIGS. 3 and 4. FIG. 3 shows the magnitude of light leakage in the bright display area and FIG. 4 shows the magnitude of light leakage in the dark display area. These graphs are data when performing bright display with a brightness of 450 cd / m ² when the display device is in the image display state, the horizontal axis indicates the position on the display portion of the display device, the vertical axis indicates the front direction, That is, it shows the luminance value in the vertical direction with respect to the screen. Also, in FIGS. 3 and 4,
The light leakage of each of the configurations using the A type polarizing plate, the B type polarizing plate, and the C type polarizing plate as the absorption type polarization selecting member 208 of the image display unit 1000, and the absorption type polarization selecting member 208 is removed from the image display unit 1000. Then, the other configuration shows the light leakage of the device similar to the display device of the present embodiment. Even if the absorption type polarization selection member 208 is removed, a normal level image can be displayed in the image display state. The details of the A, B and C type polarizing plates will be described later.

As shown in FIG. 3, in the bright display region in the mirror state, the display device of the present embodiment using the absorption type polarization selection member 208 has a higher light output than the device without the absorption type polarization selection member 208. Leakage is reduced to about half. Therefore, the display device of the present embodiment can realize a mirror that projects a reflected image having a high contrast ratio. Further, in the dark display area portion in the mirror state, as shown in FIG. 4, the display device of the present embodiment using the absorption type polarization selection member 208 has a high contrast ratio and is easy to see because there is almost no light leakage. A mirror that reflects the reflection image can be realized. on the other hand,
In the display device that does not use the absorption polarization selection member 208, a lot of light leakage occurs in the dark display region as shown in FIG.

From the above, it is shown that the display device of the present embodiment can realize a mirror with high visibility by making the display of the image display unit 1000 a dark display in the mirror state. This means that the display device having a configuration not including the absorption type polarization selection member (polarizing plate) 208 showing the light leakage in FIGS. 3 and 4 and the conventional display device showing the light leakage in FIG.
This is in contrast to the dark display, which leaks more light than the bright display.

Therefore, in the present embodiment, when the entire screen is in the mirror state, the entire image display unit 1000 is in the dark display or the illumination device itself of the image display unit 1000 is in the non-light emitting state. When only a partial area of the transmission polarization axis varying section 400 is in the voltage-on state and only a part of the screen is in the mirror state, the image display section 1000 in the area overlapping with the area to be in the mirror state is dark-displayed or Set to non-light emitting state. As a result, it is possible to reduce light leakage from the mirror-like portion and display a reflected image with a high contrast ratio.

Specifically, in order to switch to the mirror state,
When the changeover switch 813 is turned on, the image display unit 1 is operated in conjunction with the changeover switch 813.
It is possible to provide a circuit for darkening the liquid crystal element of the display unit 1000 or a circuit for turning off the illumination device on the back surface of the liquid crystal element of the image display unit 1000. If you turn off the lighting device in the mirror state,
The power consumption of the display device can be reduced. In addition, when only a part of the screen is in the mirror state and the image is displayed in the remaining part, when the illumination device on the back surface of the liquid crystal element is turned off, the display in the image display area becomes dark. It is desirable that the image display portion 1000 in the overlapping area is darkly displayed. As a result, it becomes possible to realize a mirror state that realizes a reflected image with a high contrast ratio and a bright image display on the same screen at the same time.

As the image display section 1000, a self-luminous display section such as an organic electroluminescence (EL) element can be used in addition to the one using a liquid crystal element. The absorption polarization selection member 2 is provided at a position facing the reflection polarization selection member 300 of the EL element.
08 is provided. When using an EL element,
In principle, leakage of light can be eliminated by interlocking with the switching to the mirror state and stopping the light emission itself of the EL element to set the dark display state. As a result, it is possible to realize a high-quality mirror state in which a reflected image with a high contrast ratio is obtained, and it is possible to reduce the power consumption of the display device.

Further, a discharge lamp such as a metal halide lamp is used as a light source of the illuminating device of the image display unit 1000, and by combining this with a liquid crystal element, the display device of this embodiment can be a projection type display device. it can. In this case, the discharge lamp cannot be turned on and off quickly, so in conjunction with switching to the mirror state,
It is desirable that the display of the image display unit 1000 is a dark display to reduce light leakage.

In the first embodiment, FIGS. 1 and 2 are used.
As described above, as the absorption type polarization selecting member 500, one having a transmission polarization axis parallel to the polarization axis of the first linearly polarized light and an absorption polarization axis parallel to the polarization axis of the second linearly polarized light is used. The invention is not limited to this, and the transmission polarization axis is the second.
Of which the absorption polarization axis is parallel to the polarization axis of the first linearly polarized light can be used.
In this case, the display device is switched to the image transmission state by switching the transmission polarization axis variable unit 400 to the transmission state (voltage-on state) without changing the incident polarization axis, and the transmission polarization axis variable unit 400 is changed to the first transmission state. The display device is switched to the mirror state by switching the polarized light of (1) to the second polarized light (the state of turning off the voltage).

Next, the basic configuration and operation of the display device with a function for switching to the mirror state according to the second embodiment of the present invention will be described with reference to FIGS.

In the display device of the second embodiment, the absorption type polarization selecting member 500 of the display device of FIGS. 1 and 2 of the first embodiment is replaced with the reflection type polarization selecting member 301 and the variable polarization selecting member 600. It is replaced with the combination of. Since other configurations are similar to those of the display device of the first embodiment, the same parts are designated by the same reference numerals and detailed description thereof will be omitted.

The reflection type polarization selecting member 301 is arranged at a position facing the transmission polarization axis changing unit 400, and the variable polarization selecting member 600 is closer to the viewer than the reflection type polarization selecting member 301.
Are arranged. The reflective polarization selection member 301 is the first
The linearly polarized light component is reflected and the second linearly polarized light component is transmitted. The variable polarization selection member 600 is configured to be able to select one of a state in which the first linearly polarized light component of the incident light is absorbed and a second linearly polarized light component is transmitted, and a state in which all the polarized light components are transmitted. Is.

In the display device of the second embodiment, the image display state and the mirror state are controlled by controlling the polarization state by the transmission polarization axis varying section 400 and controlling the absorption or transmission of the polarization by the variable polarization selection member 600. It is configured to be switched. The observer observes the display device from the variable polarization selection member 600 side.

Here, as the variable polarization selection member 600, a member including a guest-host type liquid crystal layer 607, transparent electrodes 603 and 606 for applying a voltage to the liquid layer layer 607, and a changeover switch 600a is used. When the changeover switch 600a is off, as shown in FIG.
The liquid crystal layer 607 is oriented so that the long axis of the liquid crystal molecule 607a of No. 7 is parallel to the first linearly polarized light. Accordingly, the variable polarization selection member 600 absorbs the first linearly polarized light component and transmits the second linearly polarized light component whose polarization axis is orthogonal to the first linearly polarized light component in the off state. Also, the changeover switch 60
0a is on, liquid crystal molecules 607a as shown in FIG.
Is perpendicular to the transparent electrodes 603 and 606, the variable polarization selection member 600 transmits all polarization components.

The operation when the display device of the second embodiment is in the image display state will be described with reference to FIG. In the case of the image display state, the changeover switch 813 is turned off to turn off the transmission polarization axis variable unit 400, and in conjunction with this, the changeover switch 600a is also turned off to turn off the variable polarization selection member 600.

Image light 3 emitted from the image display unit 1000
001 passes through the reflection type polarization selection member 300 and enters the transmission polarization axis varying unit 400. At this time, since the transmission polarization axis varying unit 400 is in the off state, the passing image light 30
01 changes from the first linearly polarized light to the second linearly polarized light.
Since the image light 3001 transmitted through the transmission polarization axis variable unit 400 is the second linearly polarized light, the polarization axis matches the transmission polarization axis of the reflection type polarization selection member 301 and is transmitted therethrough. Furthermore, since it also coincides with the transmission polarization axis of the variable polarization selection member 600 in the off state, this also transmits and is observed by the observer.

On the other hand, the external light 3002 incident on the display device in the image display state from the observer side is non-polarized, but the tunable polarization selection member 600 is in the off state. The matching first linearly polarized light component is absorbed, and only the second linearly polarized light component that matches the transmission polarization axis is transmitted. The second linearly polarized external light 3002 that has passed through the variable polarization selection member 600 passes through the reflective polarization selection member 301 and, when passing through the transmission polarization axis variable unit 400, the first linearly polarized light from the second linearly polarized light. The light is changed to linearly polarized light, transmitted through the first reflective polarization selection member 300, and enters the liquid crystal layer of the image display unit 1000. At this time, as described in the first embodiment, the light incident on the dark display region is absorbed by the absorptive polarization selection member arranged closer to the lighting device than the liquid crystal layer. Therefore, it does not return to the observer side. Further, the light incident on the bright display region also passes through the absorption type polarization selection member on the light source side and reaches the illumination device, and a part thereof is reflected, but the reflected light is substantially the same as the illumination light, It becomes a part of the illumination light. That is, in the display device of the present embodiment, even when external light enters in the image display state, there is almost no reflection of external light that deteriorates image quality.

Therefore, in the image display state, the image light 3001
To the observer with almost no loss, a bright image can be obtained. Further, since the external light 3002 is hardly reflected by the display device, deterioration of image quality such as reflection of external light and deterioration of contrast ratio does not occur.

Next, the operation of the display device of the second embodiment in the mirror state will be described with reference to FIG. In the case of the mirror state, the changeover switch 813 and the changeover switch 600a are interlocked and turned on, and the transmission polarization axis variable unit 400 and the variable polarization selection member 600 are turned on.

In the mirror state, all the polarization components of the external light 3002 incident on the display device from the observer side are transmitted through the variable polarization selection member 600, as shown in FIG. The external light 3002 transmitted through the variable polarization selection member 600 enters the reflection type polarization selection member 301. Of the external light 3002 incident on the reflection type polarization selection member 301, the second linear polarization component is transmitted through the reflection type polarization selection member 301, and the first linear polarization component is reflected by the reflection type polarization selection member 301, and again. The light passes through the variable polarization selection member 600 and goes to the viewer side. On the other hand, the second linearly polarized light component transmitted through the reflective polarization selection member 301 is
The light passes through the transmission polarization axis variable unit 400 without changing the polarization axis, is reflected by the reflective polarization selection member 300, and again passes through the transmission polarization axis variable unit 400, the reflection polarization selection member 301, and the variable polarization selection member 600. Then go to the observer side.

As described above, in the display device of the second embodiment, the incident external light 3002 is reflected by the reflection type polarization selecting member 3.
00 and the reflective polarization selection member 301 reflect most of the polarization components. Therefore, a mirror state in which an extremely bright reflection image is obtained can be obtained.

On the other hand, in the mirror state, the image display unit 100
The image light (bright display light) 3001 emitted from 0 is the absorption type polarization selection member 20 as described in the first embodiment.
Since it has passed through 8, it is the first linearly polarized light. Therefore, the image light 3001 is transmitted through the reflection-type polarization selection member 300, then is transmitted through the transmission polarization axis variable section 400 as the first linearly polarized light without being changed in polarization axis, and is reflected by the reflection-type polarization selection member 301. Then, since it returns to the image display unit 1000, it is hardly observed by the observer.

The image display unit 1000 in the mirror state
In order to further reduce the leakage of light from the side, as described in the first embodiment, the display area of the image display unit 1000 corresponding to the area in the mirror state may be darkened. desirable. When the entire display area is a mirror area, light leakage can be eliminated by turning off the illumination device of the image display unit.

As described above, in the display device of the second embodiment, almost the polarized component of the external light 3002 is reflected in the mirror state, so that an extremely bright reflected image is obtained and the light of the image light 3001 is obtained. A leak-free, easy-to-see mirror can be obtained. Further, in the image display state, as in the first embodiment, it is possible to display a bright image with less reflection of external light.

In the second embodiment, as the second reflection type polarization selection member 301, the reflection polarization axis is parallel to the polarization axis of the first linearly polarized light as shown in FIGS. Although the polarization axis parallel to the polarization axis of the second linearly polarized light is used, the present invention is not limited to this configuration, and the reflection polarization axis is parallel to the polarization axis of the second linearly polarized light and A polarization axis parallel to the polarization axis of the first linearly polarized light can be used. In this case, the transmission polarization axis varying unit 400 is switched to a state of transmitting without changing the incident polarization axis (voltage-on state), and the variable polarization selecting unit 600 is changed to
By switching to a state in which the second linearly polarized light is absorbed and the first linearly polarized light is transmitted (voltage-off state), the display device is switched to the image transmitting state, and the transmission polarization axis variable unit 400 is
The variable polarization selection unit 6 is switched to a state (voltage-off state) in which the first linearly polarized light is changed to the second linearly polarized light.
By switching 00 to a state in which all polarized components are transmitted (voltage-on state), the display device can be configured to switch to a mirror state.

In the first and second embodiments described above, when the liquid crystal element is used as the image display unit 1000, the transmissive liquid crystal element including the illuminating device has been described, but the reflective liquid crystal element is used. It is also possible to use.

The degree of polarization of the absorption type polarization selecting member 208 constituting the image display member is P1, and the absorption type polarization selecting member 5 is P1.
When the degree of polarization of 00 is P2, 0.966 ≦ P1 ≦
Satisfies the relation of 0.995 ≦ P2, or 0.96
It is desirable to satisfy the relationship of 6 ≦ P2 ≦ 0.995 ≦ P1. The reason for this will be described in a second embodiment described later.

In the display devices of the first and second embodiments, it is preferable to form an antireflection film on the surfaces of the absorption type polarization selecting members 500 and 208 and the outermost surface of the variable polarization selecting member 600.

Further, in the present invention, the reflection type polarization selecting member 30 is used.
The distance between 0 and the reflection type polarization selection member 301 is 0.11 mm.
The following is preferable. The reason for this will be described in a second embodiment described later.

Further, in the present invention, when the display device is in a mirror state, it is preferable that the entire area of at least 58.6 mm × 39.1 mm is substantially a mirror.
This is a size determined in consideration of projecting a quarter of the face of an adult male. This will also be described in the examples below.

Further, in the first and second embodiments, a film-shaped member can be used as the reflection type polarization selection members 300 and 301. In this case, the film-shaped member is made to have high rigidity and flatness through a transparent adhesive,
And whether it adheres directly to a transparent, optically isotropic transparent substrate,
Alternatively, it is desirable to indirectly adhere and fix it through a flat film or the like so that the reflecting surface is not distorted.

Further, the display device of the first and second embodiments can be a projection type display device in which the projection light emitted from the projection device is applied to the transmissive screen via the mirror member. In this case, on the transmissive screen,
It may be configured to include a mirror function unit. In this case, the projection device emits, as the projection light, linearly polarized light in which the polarization states of the respective color lights match, and the linearly polarized light becomes s-polarized light or p-polarized light with respect to the reflecting surface of the mirror member. Configure as follows.

Furthermore, of the mirror function part and the optical system constituting the transmissive screen, the mirror function part may be detachable, and the mirror function part may be removed when the mirror function is unnecessary. Alternatively, a screen that does not include an image display unit but independently has a mirror function unit is configured,
The mirror function screen may be attached to any display device as needed.

In the first and second embodiments, as the reflection type polarization selecting members 300 and 301, conductive metal linear patterns are arranged at a pitch of a few thousand angstroms (10 ^-10 m). Can be used. At this time, the longitudinal direction of the metal linear pattern becomes the reflection polarization axis. In addition, a few thousand hundred angstroms (10
^A conductive metal linear pattern is formed at a pitch of ^-10 m), and a part of adjacent linear patterns is electrically connected, so that the transparent electrode and the reflection-type polarization selection member can be used in common. it can. Thereby, the transparent electrode 606 and the reflection-type polarization selection member 301 or the reflection-type polarization selection member 3
01 and the transparent electrode 403, or the transparent electrode 406 and the reflective polarization selection member 300 can be configured.

In the first and second embodiments, the image display member 1000 can have the following structure. That is, a pair of transparent substrates bonded with a certain gap, a liquid crystal layer sandwiched between these transparent substrates, and pixel electrodes arranged in a matrix formed by transparent electrodes on at least one of the pair of transparent substrates. Group and absorption type polarization selection member 208 arranged on the observer side
And a liquid crystal element including an absorptive polarization selection member arranged on the transparent substrate on the side opposite to the observer side, a display liquid crystal element drive unit for applying a voltage corresponding to an image signal to the pixel electrode group,
A configuration including an illuminating device arranged on the back surface of the display liquid crystal element can be adopted. At this time, lighting of the lighting device,
A configuration may be provided in which a switching unit that switches the light-out state in conjunction with the switching switch 813 is provided. The lighting device includes a light source that sequentially emits a plurality of color lights, and the liquid crystal element can be configured to perform field sequential color display in accordance with the color light from the lighting device.

Further, the image display section 1000 may be configured to use a reflective liquid crystal element. in this case,
As the reflective liquid crystal element, a transparent substrate and a reflective substrate having a reflective portion are bonded together via a spacer such as beads, the periphery is sealed with a frame-shaped sealing material, and liquid crystal is placed in the gap between the two substrates. What was enclosed and sealed can be used. At this time, retardation plates are laminated and arranged on the transparent substrate. Note that the transparent substrate or the reflective substrate can be provided with a color filter. This color filter preferably has a function of increasing the darkness in dark display, and more specifically, it is more preferable to use a color filter of delta arrangement.

In the display devices of the first and second embodiments, the size of the mirror display area and the size of the image display area in the image display state may be different. Further, as the image display unit 1000, a display liquid crystal element that functions as a transmissive type in a part of the display area and a reflective type in the other area, and an illuminating device for illuminating the area that functions as the transmissive type. It is possible to use a configuration including

Further, in the display devices of the first and second embodiments, the display area of the image display section is divided into a plurality of areas, and switching control between the mirror state and the image display state is performed for each divided area. It may be configured. In order to achieve this, the light transmission surface of the transmission polarization axis variable unit 400 or the variable polarization selection member 600 is divided into a plurality of regions, and a state in which the polarization axis of the light transmitted for each individual region is changed and a state in which it is not changed. It is possible to adopt a configuration in which selection control with respect to and polarized light to be absorbed is controlled.

[0072]

EXAMPLES Examples of the present invention will be described below.

(Embodiment 1) A display device having a function of switching to a mirror state according to Embodiment 1 of the present invention will be described with reference to FIGS. 7 and 8. The display device of Example 1 has the same basic configuration as the display device shown in FIGS. 1 and 2 of the first embodiment.

Similar to the first embodiment, the display device of FIG. 7 of the first embodiment has the image display units 1000, which are sequentially stacked.
A reflective polarization selection member 300, and a transmission polarization axis variable unit 4
00 and an absorption type polarization selection member 500. These are housed in a housing 1070 having an opening 1071. The opening 1071 serves as an image display unit that can be switched to a mirror state. The operation of each part is as described in the first embodiment.

As shown in FIGS. 7 and 8, the image display unit 1000 includes a liquid crystal display element, and a liquid crystal display panel 200 for displaying an image by adjusting the amount of transmitted light, and a liquid crystal display panel 200 disposed behind the liquid crystal display panel 200. Lighting device 100. The liquid crystal display panel 200 includes a TN (Twisted Nematic) mode, an STN (Super Twisted Nematic) mode, and an ECB.
It is desirable to use a liquid crystal display panel using a display mode such as (Electrically Controlled Birefringence) mode. Since such a liquid crystal display panel performs display by modulating the polarization state of light incident on the liquid crystal layer using a polarizing plate, a high contrast ratio can be obtained with a relatively low driving voltage. Further, the absorption polarization selection member 208 arranged on the reflection polarization selection member 300 side of the liquid crystal display panel 200.
The linearly polarized light is emitted as image light by the polarizing plate functioning as.

The liquid crystal display panel 200 is, as is generally known, a liquid crystal display panel by active matrix drive using a switching element such as a TFT (Thin Film Transistor) and a liquid crystal display panel by multiplex drive. There are two methods, and either one can be selected and used. Specifically, TN (Twisted Nematic)
Liquid crystal display panel, IPS (In Plane Switching) liquid crystal display panel, MVA (Multi-domain Vertical Aligne)
d) A liquid crystal display panel driven by active matrix such as a liquid crystal display panel, or STN (Super Twisted Nema)
tic) A multiplex drive liquid crystal display panel such as a liquid crystal display panel can be used. In the first embodiment, a case where a TN liquid crystal display panel is used as the liquid crystal display panel 200 will be described, but the present invention is not limited to this.

The detailed configuration of each part of the display device according to the first embodiment will be described with reference to FIG.

The lighting device 100 includes a liquid crystal display panel 200.
The one that can uniformly illuminate the image display part of is used. As the lighting device, an edge light system (light guide system), a direct system (reflector system), a planar light source system, etc. (liquid crystal display technology, p252-256, Sangyo Tosho Co., Ltd., issue date 1)
November 8, 996: Full-color liquid crystal display technology, p20
1-202, Trikeps Co., Ltd., date of issue: February 26, 1990) is generally known. Lighting device 10
As 0, an optimum method may be selected from these methods and other methods in accordance with the use, purpose and screen size. Here, a case where an edge light type lighting device is used as the lighting device 100 will be described, but the present invention is not limited to this.

The illuminating device 100 includes a light guide body 103 made of a transparent acrylic resin on the back surface of which a dot printing 105 with a white pigment is applied, and a line made of, for example, a cold cathode tube arranged on the end face of the light guide body 103. The light source 101, the lamp cover 102, the reflection sheet 104 arranged on the back surface of the light guide body 103, the diffusion sheets 110 and 112 arranged on the front surface of the light guide body 103, and the prism sheet 111.

In this structure, the light emitted from the light source 101 is directly or after being reflected by the lamp cover 102,
It is incident on the light guide body 103. Light 1 incident on the light guide 103
101 propagates in the light guide 103 while being totally reflected,
The light reaching the dot printing 105 with the white pigment applied to the back surface of the light guide 103 changes its traveling direction and is emitted from the front surface side of the light guide 103. The light emitted from the light guide 103 is applied to the liquid crystal display panel 200 after the emission angle distribution and the in-plane luminance distribution are made uniform by the diffusion sheets 110 and 112, the prism sheet 111, and the like.

The liquid crystal display panel 200, as shown in FIG.
It includes a first transparent substrate 201 and a second transparent substrate 202 which are flat and transparent and are made of optically isotropic glass or plastic. On the transparent substrate 201, a color filter (not shown), a transparent electrode 203 made of ITO (Indium Tin Oxide), and an alignment film 204 made of a polyimide polymer are laminated. Second transparent substrate 202
Includes an alignment film 206, a transparent electrode 205 for forming pixels,
In addition, switching elements (not shown) such as electrodes and thin film transistors connected to the electrodes are formed. The two transparent substrates 201 and 202 are made to face each other with the surfaces on which the alignment films 204 and 206 are formed facing each other.
A constant gap is provided between 202 via a spacer (not shown), and the periphery is further sealed by a frame-shaped sealing material 210 to form a space inside. By enclosing a nematic liquid crystal having a positive dielectric anisotropy in this space, the liquid crystal layer 207 is formed.
Is provided.

The major axis alignment direction of the liquid crystal molecules of the liquid crystal layer 207 is defined by subjecting the alignment films 204 and 206 formed on the two transparent substrates 201 and 202 to alignment treatment such as rubbing. Here, the transparent substrates 201 and 202
It is in a state of being continuously twisted by 90 °. A polarizing plate 209 and an absorption type polarization selection member (polarizing plate) 208 are provided on the back surface of the transparent substrate 202 and the front surface of the transparent substrate 201, respectively.
However, they are arranged so as to transmit linearly polarized light whose polarization axes are orthogonal to each other. Transparent substrate 202 side and transparent substrate 201
The alignment directions of the long axes of the liquid crystal molecules on the side are configured so as to be parallel or both orthogonal to the transmission polarization axes of the polarizing plate 209 and the absorption polarization selection member (polarizing plate) 208.

As the absorption type polarization selection member (polarizing plate) 208 and the polarizing plate 209, for example, a protective layer of triacetyl cellulose is provided on both surfaces of a film having a polarizing function by absorbing iodine in stretched polyvinyl alcohol. What was done can be used. The absorptive polarization selection member (polarizing plate) 208 and the polarizing plate 209 are adhered to the transparent substrate 202 and the transparent substrate 201 by an acrylic adhesive so as to be optically coupled.

With such a configuration, the liquid crystal display panel 2
Of the illumination light incident from the back surface of 00 (illumination device 100 side), the linearly polarized light transmitted through the polarizing plate 209 is the liquid crystal layer 20.
After passing through 7, the light enters the absorption type polarization selection member (polarizing plate) 208. At this time, the polarization state of the light passing through the liquid crystal layer 207 can be changed by the voltage applied to the liquid crystal layer 207. Therefore, the voltage corresponding to the image information transmitted from the image information generator (not shown) is applied to the transparent electrodes 203, 2
05, and an electric field is applied to the liquid crystal layer 207, thereby changing the polarization state of light passing through the liquid crystal layer 207 and controlling the amount of light transmitted through the absorption type polarization selection member (polarizing plate) 208. . As a result, desired image light composed of linearly polarized light can be formed.

Next, the reflection type polarization selecting member 300 will be described.

The reflection type polarization selecting member 300 has a function of transmitting the first linearly polarized light component emitted from the image display unit 1000 and specularly reflecting the second linearly polarized light component having a polarization axis orthogonal to the first linearly polarized light component. To use. As such a member, for example, International Publication Number of International Application: WO95 /
Use of a birefringent reflection type polarizing film in which a plurality of different birefringent polymer films are alternately laminated as disclosed in No. 27919, or a cholesteric liquid crystal layer having quarter wavelength plates on the front and back sides thereof is used. You can In the case of a birefringent reflection type polarizing film, a predetermined linearly polarized light component is transmitted,
A film that specularly reflects a linearly polarized light component whose polarization axis is orthogonal to this is commercially available from 3M Company (USA) under the trade name of DBEF, and this can be used as the reflection type polarization selection member 300. The reflection type polarization selection member 300
Is an important member that functions as a mirror surface when the present display device is made into a mirror state, and therefore, a member that has not been subjected to a treatment such as matte treatment that blurs a reflected image is used.

On the other hand, as the reflection type polarization selecting member 300,
When the cholesteric liquid crystal layer has a quarter-wave plate on the front and back, a liquid crystal cell containing a low-molecular-weight cholesteric liquid crystal between two alignment-treated transparent substrates and a polymer cholesteric liquid crystal layer are used. What is formed on a flat and optically isotropic transparent substrate such as glass or transparent resin can be used as the cholesteric liquid crystal layer. The cholesteric liquid crystal layer exhibits unique optical properties based on a helical molecular arrangement, and light incident parallel to the helical axis reflects circularly polarized light in one rotation direction according to the rotation direction of the cholesteric spiral. The other shows the selective reflection of transmission. Since the wavelength range of selective reflection is determined by the pitch of the molecular arrangement, it is necessary to stack and use a plurality of cholesteric liquid crystal layers having different pitches in order to cause selective reflection in the entire visible wavelength range. In this case, in order to obtain selective reflection in the entire visible wavelength range, instead of stacking multiple cholesteric liquid crystal layers with different pitches, Asia Display95 Digest, p735, T
he Institute of Television Engineers of Japan (IT
E) A cholesteric liquid crystal layer whose pitch is continuously changed as described in & The Society for Information Display (SID) may be used.

In the case where the reflection type polarization selection member 300 is a cholesteric liquid crystal layer having a quarter wavelength plate on the front and back sides thereof, it is arranged on the back side of the cholesteric liquid crystal layer, that is, on the image display section 1000 side. The four-wave plate has its slow axis set in the following direction. That is, the reflection type polarization selecting member 3 is emitted from the image display unit 1000.
The slow axis thereof is arranged so as to convert the first linearly polarized light incident on 00 into circularly polarized light transmitted through the cholesteric liquid crystal layer. On the other hand, in the quarter-wave plate which is also arranged on the front side of the cholesteric liquid crystal layer, that is, on the side of the transmission polarization axis varying section 400, the circularly polarized light transmitted through the cholesteric liquid crystal layer is the first.
The slow axis is arranged so as to be converted into the linearly polarized light of.

When the second linearly polarized light is incident on the reflection type polarization selection member having the quarter wavelength plate on the front and back of the cholesteric liquid crystal layer as described above, the second linearly polarized light is 1
By the action of the / 4 wavelength plate, the circularly polarized light that is transmitted through the cholesteric liquid crystal layer is converted into the circularly polarized light having the opposite direction, so that it is selectively reflected by the cholesteric liquid crystal layer. The circularly polarized light reflected by the cholesteric liquid crystal layer is transmitted through the quarter wavelength plate again,
By that action, it is converted into the second linearly polarized light.

Incidentally, the reflection type polarization selecting member 300 having this structure.
The quarter-wave plate used for is 1 in the entire visible wavelength range.
It is desirable to use one that functions as a quarter-wave plate. As the quarter-wave plate, a stretched polymer film having high transmittance in the visible wavelength range, for example, polyvinyl alcohol, polycarbonate, polysulfone,
Polystyrene, polyarylate, etc. can be used. In addition, mica, crystal, or a liquid crystal layer in which molecular axes are aligned in one direction can be used.

Further, generally, due to the wavelength dependence of the refractive index of the material constituting the quarter-wave plate (hereinafter referred to as wavelength dispersion), one type of retardation plate functions as a quarter-wave plate for the entire visible wavelength range. Although it is difficult to construct a retardation plate that has a wide wavelength range, at least two types of retardation plates having different wavelength dispersions are bonded so that their optical axes are orthogonal to each other.
A quarter wave plate configured to function as a quarter wave plate may be used.

When a film-shaped member such as a birefringent reflection-type polarizing film or a laminated member of a film-shaped cholesteric liquid crystal layer and a quarter-wave plate is used as the reflection-type polarized light selection member 300, Be aware of the points.

That is, since the film-like reflection type polarization selection member has low flatness as it is, the image display unit 10 is simply used.
It is difficult to realize a practically satisfactory mirror simply by disposing it on the front surface of 00. Therefore, when a film-shaped member is used as the reflection-type polarization selection member 300, it is highly rigid, flat, transparent, and optically isotropic like a glass plate or a plastic plate through a transparent adhesive. It is desirable that the material is adhesively fixed to a transparent substrate to prevent distortion.

Alternatively, in order to fix the reflection type polarization selection member 300 in a flat state, instead of adhesively fixing it to a new transparent base material, it is fixed to the liquid crystal display panel 200 or a transparent substrate of a transmission polarization axis variable unit 400 described later. It can be configured to. In any case, the reflective polarization selection member 300
When a film-shaped member is used as above, it is desirable that the member is adhesively fixed to another flat member in order to realize a mirror without distortion.

Next, the transmission polarization axis varying section 400 will be described.

When the incident linearly polarized light is transmitted, the transmission polarization axis varying unit 400 changes its polarization state to change it into linearly polarized light whose polarization axis is orthogonal to that of the incident linearly polarized light. The configuration is such that one of the states in which the polarization state is not changed can be selected, and for example, a liquid crystal element as shown in FIG. 8 can be used.

In this transmission polarization axis varying section 400, a transparent electrode 403 made of ITO and a first transparent substrate 401 on which an alignment film 404 made of a polyimide polymer is entirely laminated, and a transparent electrode 406, And alignment film 405
Includes a second transparent substrate 402 and a liquid crystal layer 407 that are entirely laminated. The two transparent substrates 401 and 40
The transparent electrodes 403 and 406 respectively formed on 2 are connected to a power source via a wiring (not shown) and a changeover switch 813 (see FIG. 1, not shown in FIG. 8).
Therefore, either the state in which no voltage is applied to the transparent electrodes 403 and 406 or the state in which a voltage is applied can be selected. That is, there is no potential difference between the transparent electrodes 403 and 406, and no electric field is applied to the liquid crystal layer 407.
Either of the states in which the electric field is applied to 07 is selectable.

Liquid crystal layer 407 of transmission polarization axis varying unit 400
Arranges the two transparent substrates 401 and 402 so that the surfaces on which the alignment films are formed face each other, and sandwiches a spacer (not shown) to provide a fixed gap between the two transparent substrates 401 and 402. The periphery is sealed with a sealing material 410 in a frame shape to form a space, and a nematic liquid crystal having a positive dielectric anisotropy is sealed in the space.

Here, as the transmission polarization axis variable portion 400, the alignment film 4 formed on the two transparent substrates 401 and 402 is used.
04 and 405 are each subjected to an alignment treatment such as a rubbing treatment so that the liquid crystal molecule long axis of the liquid crystal layer 407 has two transparent substrates 40.
It is configured so that it is twisted by 90 ° continuously between 1,402,
The case of a so-called TN liquid crystal element will be described.

In this case, the alignment direction of the long axis of the liquid crystal molecule on the transparent substrate 402 side is configured to be parallel or orthogonal to the linear polarization transmission polarization axis of the absorption type polarization selection member (polarizing plate) 208 of the liquid crystal display panel 200. , The liquid crystal layer 407 is configured to satisfy the conditions of the waveguide in the visible wavelength range. Wave guide conditions are, for example, J. Phys. D: App
L. Phys. Vol. 8 (1975), pp. 1575-1584 C.
It is described in a paper by H. Gooch and HA Tarry.

Here, assuming that the birefringence of the liquid crystal is Δn and the thickness of the liquid crystal layer is d, Δn = 0.4452 (wavelength 63
3 nm).

With the above configuration, the transmission polarization axis varying portion 400 of this embodiment has no potential difference between the transparent electrodes 403 and 406 formed on the two transparent substrates 401 and 402, respectively, and no electric field is applied to the liquid crystal layer 407. In the state, the first linearly polarized light emitted from the image display unit 1000 and transmitted through the reflection-type polarization selection member 300 has a second polarization axis orthogonal to the first linearly polarized light.
Changes to linearly polarized light. On the other hand, two transparent substrates 40
Transparent electrodes 403 and 40 respectively formed on
In the ON state in which a voltage is applied to the liquid crystal layer 6 and an electric field is applied to the liquid crystal layer 407, the polarization axis of the first linearly polarized light emitted from the image display unit 1000 and transmitted through the reflection type polarization selection member 300 is changed. Transparent without. At this time, the transparent electrode 40
If the voltage applied to 3,406 was ± 5 V and 60 Hz, it worked well.

In the first embodiment, the transmission polarization axis changing unit 40 is used.
Although the case of a TN liquid crystal element is shown as 0, the present invention is not limited to this. That is, the transmission polarization axis varying unit 400 changes the polarization axis when the incident linearly polarized light is transmitted and changes the polarization axis to change the incident linearly polarized light into linearly polarized light having a polarization axis orthogonal to each other. It is only necessary to select a part that can be selected to either of the above states, and the ECB (Electrically Controlle) other than the above TN liquid crystal element.
A liquid crystal element, a ferroelectric liquid crystal element, an antiferroelectric liquid crystal element, or the like can be used.

Next, the absorption type polarization selecting member 500 will be described.

The absorption type polarization selection member 500 absorbs the first linearly polarized light component of the incident light and transmits the second linearly polarized light component whose polarization axis is orthogonal to this, or the first linearly polarized light component is It has a function of transmitting and absorbing the second linearly polarized light component, and a so-called polarizing plate can be used. That is, as the absorptive polarization selecting member 500, for example, a polarizing plate in which a protective layer of triacetylcellulose is provided on both surfaces of a film in which stretched polyvinyl alcohol absorbs iodine to impart a polarizing function can be used.

The absorption type polarization selecting member 500 is preferably subjected to a process of suppressing regular reflection on the surface thereof in order to suppress deterioration of image quality due to reflection. However, what is important here is that the display device of the present invention also functions as a mirror. Therefore, as a treatment for preventing specular reflection of the absorption type polarization selection member 500, fine irregularities are formed on the surface or transparent fine particles are contained on the surface. A method of reducing the specular reflection component by forming a transparent resin layer is not desirable. This is because when such processing is performed, the image display performance is improved by reducing the reflection, but the image reflected on the mirror is blurred and the performance of the mirror is deteriorated.

Therefore, in order to prevent regular reflection of the absorption type polarization selection member 500, it is desirable to form an antireflection film on the surface thereof. A known technique can be used for the antireflection film. That is, it is possible to use a method in which several kinds of optically designed metal oxides having different refractive indexes are multilayer-coated by vapor deposition, or a method in which a low refractive index material such as a fluorine compound is applied.

Next, the axial direction of each member of the display device of this embodiment will be described with reference to FIG.

Here, the absorption type polarization selection member 500 is
The case where the first linearly polarized light component of the incident light is absorbed and the second linearly polarized light component whose polarization axis is orthogonal to this is transmitted. The angle of each axis is shown as an angle counterclockwise with respect to the horizontal position of the image display surface at 3 o'clock. As shown in FIG. 9, when a TN liquid crystal display panel is used as the liquid crystal display panel 200 that constitutes the image display unit 1000, in order to obtain horizontal symmetry of viewing angle characteristics, transmission of linearly polarized light of a polarizing plate is normally performed. The polarization axis is 135 ° (or 45 °, 135 ° in this embodiment). Therefore, the transmission polarization axis of the linearly polarized light of the reflection type polarization selection member 300 is also 135 °, and the alignment directions of the liquid crystal molecule long axes on the transparent substrate 402 side and the transparent substrate 401 side of the transmission polarization axis varying unit 400 are 135 °, respectively. The transmission polarization axis of linearly polarized light of the absorption polarization selection member 500 is 45 °.

Next, the operation of the display device of the first embodiment will be described with reference to FIGS. 10 and 11.

The case where the display device of Example 1 is in the image display state will be described with reference to FIG. When the display device is in the image display state, the transmission polarization axis variable unit 400 turns off the changeover switch 813 so that the liquid crystal layer 407 forming the display unit is in a state in which no voltage is applied, that is, in an off state. The light is emitted from the illumination device 100 of the image display unit 1000,
Absorption-type polarization selection member (polarizing plate) of the liquid crystal display panel 200
The linearly polarized light that has passed through 208 is emitted from the image display unit 1000 as image light 3001. The image light 3001 composed of the first linearly polarized light is reflected by the reflective polarization selection member 300.
Through the transmission polarization axis changing unit 400. The image light 3001 passing through the variable transmission polarization axis unit 400 changes from the first linearly polarized light to the second linearly polarized light. Second linearly polarized image light 3001 transmitted through the transmission polarization axis varying unit 400
Enters the absorption polarization selection member 500. Since the absorption-type polarization selection member 500 absorbs the first linear polarization component and transmits the second linear polarization component, the image light 3001 of the second linear polarization passes through the absorption-type polarization selection member 500 and is observed. Observed by the person.

On the other hand, the external light 3002 incident on the display device from the viewer side (left side in the figure) is unpolarized light, but when transmitted through the absorption type polarization selection member 500, the first linearly polarized light component is absorbed. , The second linearly polarized light component is transmitted. The external light 3002 transmitted through the absorption type polarization selection member 500 is transmitted from the second linearly polarized light into the first linearly polarized light when being transmitted through the transmission polarization axis varying unit 400.
Changes to linearly polarized light, passes through the reflective polarization selection member 300, and travels toward the image display unit 1000. As described in the first embodiment, this light hardly returns to the observer side.

Therefore, in the image display state, the image display unit 1
The image light 3001 emitted from 000 goes to the observer with almost no loss, so that a bright image can be obtained. Further, since the external light 3002 is not reflected by the reflection-type polarization selection member 300 that functions as a mirror in the mirror state, there is almost no deterioration in image quality due to external light such as glare and a decrease in contrast ratio. .

FIG. 11 shows a case where the display device is in a mirror state. When the display device is in the mirror state, the transmission polarization axis variable unit 40
0 turns on the changeover switch 813 so that an electric field is applied to the liquid crystal layer 407 that constitutes it. In this case, the external light 3002 traveling from the observer side to the display device is non-polarized light, but the absorption type polarization selection member 50.
When passing 0, the first linearly polarized light component is absorbed and the second linearly polarized light component is absorbed.
Only the linearly polarized light component of
Incident on. At this time, the external light 3002 that has entered the transmission polarization axis varying unit 400 passes through the transmission polarization axis varying unit 400 as the second linearly polarized light without changing the polarization axis, and reaches the reflection type polarization selection member 300. Reflective polarization selection member 300
Since the first linearly polarized light component is transmitted and the second linearly polarized light component is specularly reflected, the external light 3002 is reflected by the reflective polarization selection member 300. The external light 3002 reflected by the reflection-type polarization selection member 300 passes through the transmission polarization axis variable unit 400 as the second linearly polarized light without changing the polarization axis, and further passes through the polarization selection member 500 toward the viewer. Therefore, the mirror state is realized.

At this time, since the image display section 1000 of this embodiment is provided with the absorption type polarization selecting member (polarizing plate) 208, the image light in the dark display region is absorbed by the absorption type polarization selecting member (polarizing plate) 208. And is absorbed by the reflection type polarization selection member 30.
It never reaches zero. Therefore, the reflective polarization selection member 30
Regardless of the reflection performance of 0, the leakage of light from the dark display area can be significantly reduced.

Of the image light emitted from the image display section 1000, the image light 3001 emitted from the bright display area.
Passes through the reflection type polarization selection member 300 and enters the transmission polarization axis variable unit 400. When the display device is in the mirror state, the transmission polarization axis varying unit 400 is in the ON state, and at this time, the image light 3001 transmitted through the transmission polarization axis varying unit 400 is the first linearly polarized light without the polarization axis changing. Since it is transmitted as it is, it is absorbed by the absorption type polarization selection member 500 and is hardly observed by the observer.

That is, in the case of the mirror state, the light from the image display member does not reach the observer, while the outside light 3002 incident on the display device from the surroundings is ideally half of the unpolarized light. Since the light is reflected by the reflective polarization selection member 300 and is directed toward the viewer side, it functions as a bright mirror.

In addition, the display device of the present embodiment has a configuration in which the transmission polarization axis varying portion 400 is turned on and the liquid crystal molecules 407a stand in the mirror state. In the nematic liquid crystal, in general, the deviation of the polarization axis of light emitted obliquely is smaller when the voltage-on liquid crystal molecules are erected than when the voltage-off liquid crystal molecules are twisted. Therefore, in the display device of this embodiment, the image light (bright display light) 3001 is slanted in the mirror state in the mirror state, as compared with the structure described in the related art in which the voltage is turned off in the mirror state. The effect of less light leakage is also obtained.

The characteristics of the polarizing plate functioning as the absorption type polarization selecting member 208 and the absorption type polarization selecting member 500 are directly related to the image quality in the image display state and the visibility of the mirror in the mirror state. Specifically, it is desirable that the transmittance of the polarizing plate is high because it contributes to the brightness of the image in the image display state and the brightness of the reflected image in the mirror state. The degree of polarization of the polarizing plate is directly related to the contrast ratio in the image display state and the amount of unnecessary reflection of external light. The higher the degree of polarization of the polarizing plate, the higher the contrast ratio of image display and the reduction of unnecessary reflection of external light. Therefore, the degree of polarization of the polarizing plate is preferably high. Even in the mirror state, the higher the degree of polarization, the smaller the light leakage from the image display member, the higher the contrast ratio of the reflected image, and the more visible the mirror state is. desirable.

Therefore, it is desirable to use a polarizing plate having a high transmittance and a high degree of polarization as the polarizing plate used as the absorption type polarization selecting member 208 or the absorption type polarization selecting member 500. However, in general, the relationship between the transmittance and the degree of polarization of a polarizing plate is shown in FIG.
There is a trade-off relationship as illustrated in (Nitto Giho, Vol38, No.1, May, 2000, pp11-14). FIG. 12 is a graph showing a general relationship between the transmittance of an iodine-based polarizing plate and the degree of polarization, wherein the horizontal axis represents the transmittance of the polarizing plate and the vertical axis represents the degree of polarization. Therefore, selection of the characteristics of the polarizing plates used as the absorption polarization selection member 208 and the absorption polarization selection member 500 is extremely important for achieving both the image quality in the image display state and the mirror performance in the mirror state.

FIGS. 3 and 4 are graphs showing the leakage of light from the image display section 1000 in the mirror state. FIG. 3 shows the magnitude of light leakage in the bright display portion, and FIG. 4 shows the magnitude of light leakage in the dark display portion. These graphs are data under the condition that bright display with a luminance value of 450 cd / m ² is performed when the display device is in the image display state, the horizontal axis indicates the position on the display device display portion, and the vertical axis indicates the front direction. Shows the brightness value at. In addition, A type polarizing plate in the figure,
The B-type polarizing plate and the C-type polarizing plate show the types of polarizing plates used as the absorption-type polarization selection member 208. For comparison, the absorption-type polarization selection member 208 is omitted, and other configurations are the same as those of the display device of the first embodiment. The light leakage when the same is also shown. The transmittance of the A-type polarizing plate in FIGS. 3 and 4 is 41.5% and the polarization degree is 99.97%, and that of the B-type polarizing plate is 43.6% and the polarization degree is 99.97%.
5%, C type polarizing plate has a transmittance of 45.4% and a polarization degree of 96.60%. In the data of FIGS. 3 and 4, an A type polarizing plate is used as the absorption type polarization selecting member 500.

As shown in FIGS. 3 and 4, the A type,
The absorption-type polarization selection member 208 is provided in any of the B-type and C-type polarization plates, so that the absorption-type polarization selection member 2 is provided.
It can be seen that the leakage of light is significantly reduced as compared with the case where there is no 08, and a mirror that projects a reflected image with a high contrast ratio can be realized. Especially, A with a polarization degree of 99.5% or more
In the case of the type and B type polarizing plates, it can be seen that as shown in FIG. 4, light leakage in the dark display portion is significantly reduced, and a high-quality mirror state in which a reflected image having a higher contrast ratio is projected can be realized.

Therefore, the polarization degree of the polarizing plate used as the absorption type polarization selection member 208 is preferably at least 96.60% or more, and the polarization degree is 99.5% or more in order to realize a higher quality mirror state. Is more desirable.

On the other hand, FIG. 13 shows an absorption type polarization selecting member 500.
Degree of polarization of the polarizing plate used as a mirror, reflectance of the mirror in the mirror state, and reflectance of external light in the image display state (unnecessary reflectance)
It is a graph which shows the relationship with. The horizontal axis represents the degree of polarization of the polarizing plate used as the absorption type polarization selection member 500, and the vertical axis represents the reflectance. As shown in FIG. 13, by reducing the polarization degree of the polarizing plate used as the absorption type polarization selection member 500 from 99.97% to 96.60% to make the transmittance higher, the reflectance in the mirror state is improved by about 10%. And a brighter mirror can be realized. At this time, the increase in unnecessary reflectance in the image display state was small.

FIG. 14 is a graph showing an example of the relationship between the polarization degree of the polarizing plate used as the absorption type polarization selecting member 208 and the brightness value of bright display in the image display state, where the horizontal axis represents the polarization degree of the polarizing plate and the vertical axis represents the vertical direction. The axis shows relative brightness. The data in FIG. 14 is the data when an A type polarizing plate is used as the absorption type polarization selecting member 500. As shown in FIG. 14, the polarization degree of the polarizing plate used as the absorption type polarization selection member 208 is
By decreasing from 99.97% to 96.60% and using a high transmittance, the brightness value increased by about 9.5% and a brighter image was obtained. This relationship was the same when the characteristics of the polarizing plate of the absorption type polarization selection member 208 were fixed and the polarization degree of the polarizing plate of the absorption type polarization selection member 500 was changed.

If a polarizing plate having a polarization degree of 99.5% or more is used for either one of the absorption type polarization selecting member 208 and the absorption type polarization selecting member 500, the polarization degree of the other polarizing plate is 96.6% or less. Even if there was, a sufficient contrast ratio was obtained. Therefore, in order to improve the brightness while maintaining a sufficient contrast ratio in the image display state, one of the absorption-type polarization selection member 208 and the absorption-type polarization selection member 500 has a high polarization degree. Using a plate
On the other hand, it is effective to use a polarizing plate having a low degree of polarization.

From the above, when the polarization degree of the polarizing plate of the absorption type polarization selection member 208 is P1 and the polarization degree of the polarizing plate of the absorption type polarization selection member 500 is P2, the brightness and contrast of the display image in the image display state. It is desirable to satisfy the following conditions in order to achieve a high level of both the ratio and the contrast ratio of the reflected image in the mirror state and the brightness. Condition 1 0.966 ≦ P1 ≦ 0.995 ≦ P2. Condition 2 0.966 ≤ P2 ≤ 0.995 ≤ P1 is satisfied, and the image display member is always displayed in the dark state in the mirror state.

The reason why the image display member is always set to the dark display in the mirror state under the condition 2 is that the absorption type polarization selecting member 50 is used.
This is because when the degree of polarization of the 0 polarizing plate is low, the light leakage from the bright display region becomes large and the contrast ratio of the reflected image is significantly lowered. Therefore, the dark display is used to prevent light leakage and prevent the contrast ratio from decreasing.

In the display device of the first embodiment, a switching unit is provided for interlocking the turning on / off of the illuminating device 100 with the switching of the changeover switch 813 of the transmission polarization axis changing unit 400, and in the case of the full mirror state. The lighting device may be turned off. In this case, since no light is output from the image display unit 1000, it is possible to realize an easy-to-view mirror that does not leak light and can obtain a reflected image with a high contrast ratio, and it is possible to reduce the power consumption of the display device as much as the light is turned off. .

Further, when only a part of the screen is in the mirror state and the image is displayed in the remaining part, the illumination device is not turned off and the area of the image display unit 1000 corresponding to the area of the mirror state is darkly displayed. By doing so, it is possible to realize a mirror that realizes a reflected image with a high contrast ratio and a bright image display area on the same screen.

As described above, according to the display device of the present invention,
The reflection type polarization selection member 300 includes a transmission polarization axis changing unit 400.
By controlling the polarization state by, the effective transparent state,
It is switched to the state of functioning as a mirror. Therefore, in the image display state, a bright image can be obtained by effectively setting the reflective polarization selection member 300 in a transparent state. In addition, even in a bright environment, since the external light is hardly reflected by the display device, the image reflection such as the case of using a half mirror and the accompanying deterioration of the image quality such as the reduction of the contrast ratio do not occur. That is, the switching between the image display state and the mirror state can be realized without deteriorating the performance of each other.

Further, since the image display unit 1000 of this embodiment is provided with the absorption type polarization selection member (polarizing plate) 208, the image light in the dark display area is absorbed by the absorption type polarization selection member (polarizing plate) 208. Absorption and reflection type polarization selection member 30
It never reaches zero. Therefore, the reflective polarization selection member 30
Regardless of the reflection performance of 0, it is possible to significantly reduce light leakage from the dark display area in the mirror state.

In the above embodiment, the absorption type polarization selecting member 5 is used.
Although the second linearly polarized light component is transmitted as 00 and the first linearly polarized light component whose polarization axis is orthogonal to this is absorbed, the absorption type polarization selection member 500 transmits the first linearly polarized light component. As the second linearly polarized light component, one that absorbs may be used. In this case, the transmission polarization axis variable unit 4
00 is in the mirror state when no voltage is applied to the liquid crystal layer 407, that is, in the off state, and the transmission polarization axis varying unit 400 is in the image display state when the voltage is applied to the liquid crystal layer 407, that is, in the on state. That is, when the power of the entire display device is cut off, the mirror state can be obtained. This is very advantageous when the present display device is used in a device such as a handheld PC or a mobile phone whose power consumption is to be reduced as much as possible, because the mirror function can be realized without power consumption.

In the display device of the first embodiment, in order to reduce the reflection of light at the interface of the constituent members, each member may be optically coupled with a transparent adhesive having a matching refractive index. It is possible.

(Embodiment 2) A display device having a function of switching to a mirror state according to Embodiment 2 of the present invention will be described with reference to FIGS. The display device of the second embodiment has a second basic configuration.
This is the same as the display device shown in FIGS. 1 and 2 of the embodiment. That is, in the display device of the second embodiment, the absorption polarization selection member 500 of the display device described in the first embodiment is replaced with a combination of the reflection polarization selection member 301 and the variable polarization selection member 600. Therefore, the same parts as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIGS. 15 and 16, the structure of the present display device is such that the first linearly polarized light component is reflected and the second linearly polarized light component is reflected instead of the absorption type polarization selection member 500 of the display device of the first embodiment. A reflective polarization selection member 301 that transmits the linearly polarized light component of
The variable polarization selection member 6 that can be selected from a state in which the first linearly polarized light component of the incident light is absorbed and the second linearly polarized light component is transmitted and a state in which all the polarized light components are transmitted are selected.
00 are arranged in order from the transmission polarization axis variable unit 400 side.

The observer observes the display device from the variable polarization selecting member 600 side (left side in the figure).

As the image display unit 1000, the liquid crystal display panel 200 for displaying an image by adjusting the amount of transmitted light.
It is possible to use a device that is composed of the lighting device 100 and the lighting device 100 arranged on the back surface thereof.

In the second embodiment, referring to FIG. 16 below,
Similar to the first embodiment, an edge light system is used as the illumination device 100 and a TN liquid crystal display panel is used as the display panel 200, but the present invention is not limited to this.

The reflection type polarization selecting member 300 and the reflection type polarization selecting member 301 transmit a predetermined linearly polarized light component and specularly reflect a linearly polarized light component having a polarization axis orthogonal to this. As such a member, the birefringent reflection type polarizing film described in (Example 1) or a member in which a cholesteric liquid crystal layer and a quarter wavelength plate are laminated on the front and back of the cholesteric liquid crystal layer can be used.

As the reflection type polarization selection member 300 and the reflection type polarization selection member 301, a refraction reflection type polarization film or a film-shaped cholesteric liquid crystal layer and 1 /
When using a film-shaped member such as a laminated member of a four-wave plate, the following is performed. That is, since the film-shaped reflection type polarization selection member has low flatness as it is, a transparent and optically isotropic transparent substrate such as a glass plate or a plastic plate having high rigidity and flatness is provided through a transparent adhesive. It is desirable that the material be adhesively fixed to prevent distortion. The film-type reflective polarization selection member 300 and the reflection polarization selection member 301 may be adhesively fixed to a substrate of another adjacent member such as a transparent substrate of the liquid crystal display panel 200.

The transmission polarization axis varying unit 400 changes the polarization axis of the incident linearly polarized light when it is transmitted and changes the incident linearly polarized light into linearly polarized light having a polarization axis orthogonal to each other. The liquid crystal element described in (Example 1) can be used because it is a portion that can be selected to any state in which the axis is not changed.

In the present embodiment, the transmission polarization axis variable section 400 includes the reflection type polarization selecting member 300 and the reflection type polarization selecting member 301.
It is placed between and. The reflection-type polarization selection member 300 and the reflection-type polarization selection member 301 are members that function as reflection surfaces when the display device is in a mirror state. For this reason, when the distance between the reflective polarization selecting member 300 and the reflective polarization selecting member 301 becomes large, parallax occurs in the images reflected by the reflective polarization selecting member 300 and the reflective polarization selecting member 301, so that the distance between them is as small as possible. It is desirable to make it small. That is, it is desirable that the thickness of the transmission polarization axis variable section 400 arranged between the reflection type polarization selection member 300 and the reflection type polarization selection member 301 be as thin as possible.

The display device of the second embodiment is mainly used by a person to copy and observe his / her face in a mirror state. Since the average height of all faces of an adult male is 234.6 mm (Handbook of Numerical and Numerical Formulas for Ergonomics; 1992, published by Gihodo), the vertical distance from the eye to the edge of the face is half that of 117.
Assuming 3 mm, the distance between this display device in the mirror state and the eye is 30
Considering that the definition is 0 mm and the resolution of an average visual acuity of 1.0 is a minimum of 1 minute in terms of visual angle (definition of visual acuity; International Association of Ophthalmology, 1909), it is a reflection type in order not to feel parallax. The distance between the polarization selection member 300 and the reflective polarization selection member 301 is preferably 0.11 mm or less based on geometric calculation.

That is, when a glass substrate having a thickness of 0.7 mm, which is generally used for liquid crystal elements at present, is adopted as the transparent substrates 401 and 402 of the transmission polarization axis varying section 400, the image reflected when the display device is in the mirror state. Will cause parallax. Therefore, it is desirable to use transparent substrates with a thickness of 0.05 mm or less as the transparent substrates 401 and 402 in order to realize a mirror having practically no parallax. Such a transparent substrate 40
As 1, 402, glass or polymer film can be used. As the polymer film, triacetyl cellulose, which has no optical anisotropy,
Non-stretched polycarbonate or the like formed by a casting method (solution casting method) can be used.

Alternatively, the reflection-type polarization selection member 300 and the reflection-type polarization selection member 301 are arranged closer to the liquid crystal layer 407 than the transparent substrates 401 and 402, and the liquid crystal layer 407 is sandwiched between the reflection-type polarization selection member 300 and the reflection-type polarization selection member 300. Since the distance between the reflective polarization selection member 301 and the reflective polarization selection member 301 is about the thickness of the liquid crystal layer, a mirror state without parallax can be realized.

Since some parallax is allowed depending on the application, the present invention does not exclude the case where the distance between the reflection type polarization selecting member 300 and the reflection type polarization selecting member 301 is not the above value.

On the other hand, the variable polarization selecting member 600 absorbs the first linearly polarized light component of the incident light and transmits the second linearly polarized light component whose polarization axis is orthogonal to the first linearly polarized light component. It is a member that can select one of the transparent states. A guest-host type liquid crystal element can be used as such a portion. Here, a variable polarization selection member 600 using a guest-host type liquid crystal element is shown in FIG.
This will be described with reference to Nos. 7 and 18.

A variable polarization selection member 600 using a guest-host type liquid crystal element includes a first transparent substrate 601 on which a transparent electrode 603 made of ITO and an alignment film 604 made of a polyimide-based polymer are entirely laminated. Transparent electrode 60
6 and the alignment film 605 are laminated on the entire surface of the second transparent substrate 602, and a guest-host type liquid crystal layer 607 sandwiched therebetween.

The transparent electrodes 603 and 606 formed on the two transparent substrates 601 and 602, respectively, are connected to a power source through wiring and changeover switch 600a.
It is possible to select either a state in which no voltage is applied to the transparent electrodes 603 and 606 or a state in which a voltage is applied. That is, there is no potential difference between the transparent electrodes 603 and 606, and the liquid crystal layer 6
07, no electric field is applied, and the transparent electrodes 603, 6
A voltage is applied to 06 and an electric field is applied to the liquid crystal layer 407 so that either of the states can be selected.

The liquid crystal layer 607 is composed of two transparent substrates 601,
Two transparent substrates 60 are arranged with the alignment film forming surfaces facing each other, and a spacer (not shown) interposed therebetween.
A constant gap is provided between the first and second portions 602, a space is formed by sealing the periphery of this gap with a sealing material 610 in a frame shape, and a guest-host type liquid crystal is sealed in this space.

The operation of the variable polarization selecting member 600 will be described with reference to FIGS. 17 and 18. 17 and 18 are partial schematic cross-sectional views showing an example of the variable polarization selection member 600. The guest-host type liquid crystal layer 607 includes a nematic liquid crystal 6072 and a dichroic dye 6071 as a guest.
Is added. In this embodiment, a liquid crystal having a positive dielectric anisotropy is used as the nematic liquid crystal, and the alignment direction of the long axis of the liquid crystal molecule is substantially horizontal to the substrates 601 and 602 by the rubbing-treated alignment films 604 and 605, and Orientation without twist between the two transparent substrates 601 and 602,
That is, the orientation is homogeneous. At this time, a pretilt is provided such that the alignment directions near the two transparent substrates 601 and 602 are parallel to each other. The pretilt angle is preferably set to 2 ° or more so that reverse tilt does not occur. Here, the pretilt is set to about 4 °.

Here, the dichroic dye 6071 has a rod-like structure and has a property of being oriented in a direction parallel to liquid crystal molecules. Therefore, for example, when the orientation of the liquid crystal molecules is changed from the horizontal direction to the vertical direction with respect to the substrate, the orientation of the dichroic dye is changed from the horizontal direction to the vertical direction by following this. Here, a guest host liquid crystal material LA121 / 4 (trade name) manufactured by Mitsubishi Kasei Co., Ltd. was used as the liquid crystal layer 607, and the thickness of the liquid crystal layer 607 was 5 μm.

FIG. 17 shows two transparent substrates 601, 602.
A state in which there is no potential difference between the transparent electrodes 603 and 606 formed on the liquid crystal layer 607 and no electric field is applied to the liquid crystal layer 607,
That is, the changeover switch 600a is in the off state.
In this case, the nematic liquid crystal 6072 of the liquid crystal layer 607 is in an initial alignment state, that is, substantially horizontal to the substrate (left and right direction of the paper surface in the drawing).
It is a homogeneous orientation, and the dichroic dye 6071 is also oriented according to this. The dichroic dye 6071 has an absorption polarization axis substantially parallel to the molecular axis, and strongly absorbs a polarized component parallel to the molecular axis and hardly absorbs a polarized component orthogonal to this. Therefore, the incident light 5000 having various planes of polarization, which are incident from the direction substantially perpendicular to the transparent substrate surface, has an oscillation direction of an electric vector parallel to the molecular axis of the dichroic dye 6071 when passing through the liquid crystal layer 607. The linearly polarized light component Lp is absorbed, and the linearly polarized light component Ls orthogonal thereto is transmitted.

FIG. 18 shows a state in which a voltage is applied to the transparent electrodes 603 and 606 formed on the two transparent substrates 601 and 602, respectively, and an electric field is applied to the liquid crystal layer 607, that is, the changeover switch 600a is on. In this case, the alignment direction of the molecular long axis of the nematic liquid crystal 6072 changes from the horizontal direction to the vertical direction with respect to the two transparent substrates 601 and 602, and accordingly, the alignment direction of the dichroic dye 6071 also changes to the vertical direction. To do. Therefore, the incident light 50 having various planes of polarization that is incident from the direction substantially perpendicular to the transparent substrate surface
00 transmits almost all polarized components without being absorbed.
At this time, in this embodiment, the voltages applied to the transparent electrodes 603 and 606 of the transparent substrates 601 and 602 are ± 30 V and 60 Hz.
And

Therefore, if the alignment direction of the liquid crystal molecules is made to coincide with the polarization axis of the first linearly polarized light, the first linearly polarized light component of the incident light is absorbed and the second linearly polarized light is orthogonal to the first linearly polarized light component. It is possible to realize a variable polarization selection member capable of selecting either a state in which a linearly polarized light component is transmitted or a state in which all polarized light components are transmitted.

The variable polarization selection member 600 is preferably subjected to a process of suppressing regular reflection on its surface in order to suppress deterioration of image quality due to reflection of external light. However, what is important here is that the display device of the present invention also functions as a mirror. Therefore, as a process for preventing regular reflection of the variable polarization selection member 600, fine irregularities are formed on the surface or a transparent surface containing transparent fine particles is used. A method of reducing the specular reflection component by forming a resin layer is not desirable. This is because when such processing is performed, the image display performance is improved by reducing the reflection, but the image reflected on the mirror is blurred and the performance of the mirror is deteriorated. Therefore, as a process for preventing regular reflection of the variable polarization selection member 600, it is desirable to form an antireflection film on the surface thereof. A known technique can be used for the antireflection film. That is, it is possible to use a method in which several kinds of optically designed metal oxides having different refractive indexes are multilayer-coated by vapor deposition, or a method in which a low refractive index material such as a fluorine compound is applied.

FIG. 19 is an explanatory view of the axial direction of each member of this embodiment. The display of the angle of each axis is based on the position at 3 o'clock in the horizontal direction of the image display surface, and is shown in the counterclockwise direction from here. As shown in FIG. 19, the image display unit 1000
The absorption polarization selection member (polarizing plate) 208 of the TN liquid crystal display panel 200 constituting the
Let be °. Therefore, the transmission polarization axis of the linearly polarized light of the reflection-type polarization selection member 300 is also 135 °, and the transmission polarization axis variable unit 4
00 has a liquid crystal molecule major axis orientation direction of 135 ° and 45 ° on the transparent substrate 402 side and a transparent substrate 401 side, respectively, and a transmission polarization axis of linearly polarized light of the reflection type polarization selection member 301 is 45 °.
Both the transparent substrate 602 side and the transparent substrate 601 side of the variable polarization selection member 600 are oriented at 135 ° in the long axis of the liquid crystal molecules.

Next, the operation of the display device according to the second embodiment will be described with reference to the drawings. 20 and 21 are schematic configuration diagrams for explaining the basic configuration and operation of the display device.

In this embodiment, the variable polarization selection member 600 is
In the off state, the first linearly polarized light component (vertical direction in the plane of the figure) is absorbed, and the second linearly polarized light component whose polarization axis is orthogonal to this (the vertical direction in the plane of the figure) is transmitted, and in the on state, all the polarized light components The case of passing through will be described.

Further, as the transmission polarization axis varying section 400,
In the OFF state, when the incident linearly polarized light is transmitted, the polarization axis is changed to change the incident linearly polarized light into a linearly polarized light whose polarization axis is orthogonal to the linearly polarized light, and in the ON state, the polarization axis is not changed. .

FIG. 20 shows the case of the image display state. When the display device is in the image display state, the transmission polarization axis variable unit 40
0 is a state in which no voltage is applied to the liquid crystal layer 407 that constitutes it, that is, an off state. Further, the variable polarization selection member 600 is also turned off.

As described above, the image display unit 1000 is provided with the liquid crystal display panel 200 and the illumination device 1 arranged on the back surface thereof.
00, which is emitted from the lighting device 100,
Absorption-type polarization selection member (polarizing plate) of the liquid crystal display panel 200
The first linearly polarized light that has passed through 208 is emitted from the image display unit 1000 as image light 3001. Image display unit 100
Image light 300 composed of first linearly polarized light emitted from 0
Reference numeral 1 passes through the reflection type polarization selection member 300 and enters the transmission polarization axis varying unit 400.

The image light 3001 passing through the variable transmission polarization axis unit 400 changes from the first linearly polarized light to the second linearly polarized light. Image light 30 transmitted through the transmission polarization axis varying unit 400
01 is incident on the reflection type polarization selection member 301. The reflection-type polarization selection member 301 specularly reflects the first linearly polarized light component but transmits the second linearly polarized light component. Therefore, the transmission polarization axis varying unit 400 converts the image light 3001 into the second linearly polarized light. Passes through the reflection type polarization selection member 301 and enters the variable polarization selection member 600. When the display device is in the image display state, the variable polarization selection member 600 is in the off state, and the first linearly polarized light component of the light incident thereon is absorbed, but the second linearly polarized light component is transmitted. Therefore, the image light 3001 passes through the variable polarization selection member 600 and is observed by the observer.

On the other hand, the external light 3002 traveling from the observer side (left side in the figure) to the display device is unpolarized, but when the display device is in the image display state, the variable polarization selection member 600 is in the off state. The incident light absorbs the first linearly polarized light component and transmits only the second linearly polarized light component. The external light 3002 transmitted through the variable polarization selection member 600 is transmitted through the reflection type polarization selection member 301, and is changed from the second linearly polarized light to the first linearly polarized light when being transmitted through the transmission polarization axis variable section 400. The reflective polarization selection member 300 also passes through, and faces the image display unit 1000 and hardly returns to the viewer side.

Therefore, in the image display state, the image display unit 1
The image light 3001 emitted from 000 goes to the observer with almost no loss, so that a bright image can be obtained. Further, since the external light 3002 is hardly reflected by the display device, the image quality deterioration due to the external light such as glare and reduction in contrast ratio does not occur.

FIG. 21 shows the case where this display device is in a mirror state. When the display device is in the mirror state, the transmission polarization axis variable unit 40
In the case of 0, a voltage is applied to the liquid crystal layer 407 that constitutes it to turn it on. The variable polarization selection member 600 is also turned on.

Also in this case, the image light 3001 corresponding to the bright display, which is emitted from the image display section 1000 and transmitted through the reflection type polarization selecting member 300, is incident on the transmission polarization axis varying section 400. At this time, the image light 3001 transmitted through the variable transmission polarization axis unit 400 is transmitted as the first linearly polarized light without changing the polarization axis, is reflected by the reflective polarization selection member 301, and returns to the image display unit 1000. , Not observed by the observer.

On the other hand, when the display device is in the mirror state, the variable polarization selecting member 600 is in the on state, and the external light 3002 traveling from the observer side to the display device is in a transparent state for most polarization components. Most of the external light 3002 passes through the variable polarization selection member 600. The external light 3002 transmitted through the variable polarization selection member 600 enters the reflection type polarization selection member 301. Of the external light 3002 that has entered the reflective polarization selection member 301, the second linearly polarized light component passes through the reflective polarization selection member 301, and the first linearly polarized light component is
The light is reflected by the reflective polarization selection member 301, passes through the variable polarization selection member 600 again, and travels toward the viewer side. On the other hand, of the external light 3002 incident on the reflection-type polarization selection member 301, the second linearly polarized light component transmitted through the reflection-type polarization selection member 301 passes through the transmission polarization axis variable unit 400 without changing the polarization axis, The light is reflected by the reflection-type polarization selection member 300 and again passes through the transmission polarization axis variable unit 400, the reflection-type polarization selection member 301, and the variable polarization selection member 600, and goes to the viewer side.

That is, in the mirror state, the image light 3001 is reflected by the reflection type polarization selection member 301, and the image display unit 100
Since it returns to 0, it is not observed by the observer. Also, outside light 300
Most of the polarized light component 2 is reflected by the first reflection-type polarization selection member 300 and the reflection-type polarization selection member 301, and thus 2 functions as an extremely bright mirror.

As in the case of the above-described first embodiment, when the display device is set in the mirror state also in this embodiment, the image display unit 10 is used.
The corresponding portion of 00 may be darkly displayed, or the illumination device 100 forming the image display member may be turned off in conjunction with the above operation. In this case, since image light is not output from the image display unit 1000, unnecessary stray light does not impair the performance of the mirror toward the observer, and particularly when the illumination device 100 is turned off, power consumption can be reduced in the mirror state. There is also the effect.

As described above, in the display device of this embodiment, the reflection type polarization selecting member 300 and the reflection type polarization selecting member 301 are used.
Can be switched between an effectively transparent state and a state that functions as a mirror by controlling the absorption of polarized light by the variable polarization selection member 600 and controlling the polarization state by the transmission polarization axis varying section 400. Therefore, in the image display state, a bright image can be obtained by effectively setting the reflective polarization selection member 300 and the reflective polarization selection member 301 to a transparent state, and external light is displayed even in a bright environment. Since the light is hardly reflected by the device, there is no image reflection such as when a half mirror is used and deterioration of image quality such as a reduction in contrast ratio. That is, the switching between the image display state and the mirror state can be realized without deteriorating the performance of each other.

In particular, in this embodiment, when the display device is in the mirror state, the variable polarization selection member 600 is in the transparent state, and the reflection type polarization selection member 301 and the reflection type polarization selection member 300 are further included.
As a result, most of the polarized components of the external light are reflected, so that there is an effect that an extremely bright mirror that is at least twice as bright as the display device of the first embodiment can be realized.

Incidentally, in order to reduce the interface reflection of each member constituting the display device, it is possible to optically bond each member with a transparent adhesive having a matching refractive index.

In the above embodiment, the variable polarization selection member 60 is used.
As the liquid crystal layer 607 of 0, a liquid crystal having a positive dielectric anisotropy was used as a nematic liquid crystal and was in a homogeneous orientation. However, a liquid crystal having a negative dielectric anisotropy was used as a nematic liquid crystal of the liquid crystal layer 607 and an initial state (no electric field applied) In the state), it is also possible to use a homeotropic alignment in which the direction of the long axis of the liquid crystal molecule is substantially perpendicular to the transparent substrate. In this case, the transparent electrodes 603 of the two transparent substrates 601, 602,
When a voltage is applied to 606 and an electric field is applied to the liquid crystal layer 607, the alignment directions of the long axes of the liquid crystal molecules are two transparent substrates 601.
Although it changes from the vertical direction to the horizontal direction with respect to 602, it is advisable to give a slight pretilt angle to the initial alignment state of the liquid crystal so that the liquid crystal molecules are aligned in a fixed direction.

When a liquid crystal having a negative dielectric anisotropy is used as the nematic liquid crystal of the liquid crystal layer 607 and homeotropic alignment is performed, the transparent electrodes 60 of the two transparent substrates 601 and 602 are used.
In the state where there is no potential difference between Nos. 3 and 606 and no electric field is applied to the liquid crystal layer 607, that is, in the off state, the liquid crystal layer 6
In the 07 nematic liquid crystal, the direction of the long axis of the molecule is substantially perpendicular to the transparent substrate, and the dichroic dye is also oriented according to this, so that the incident light from the outside receives the liquid crystal layer 607.
It is transmitted with almost no absorption.

On the other hand, when a voltage is applied to the transparent electrodes 603 and 606 of the two transparent substrates 601 and 602 and an electric field is applied to the liquid crystal layer 607, that is, in the ON state, the alignment direction of the molecular long axis of the nematic liquid crystal is 2 Transparent substrates 601, 6
02 changes from the vertical direction to the horizontal direction, and accordingly, the orientation direction of the dichroic dye also changes to the horizontal direction. The dichroic dye has an absorption polarization axis substantially parallel to the molecular axis, and strongly absorbs a polarized component parallel to the molecular axis and hardly absorbs a polarized component orthogonal to this. Therefore, when the incident light from the outside passes through the liquid crystal layer 607, the linearly polarized light component having the vibration direction of the electric vector in the direction parallel to the molecular axis of the dichroic dye is absorbed, and the linearly polarized light component orthogonal thereto is To Penetrate.

That is, if the alignment direction of the liquid crystal in the state where the electric field is applied to the liquid crystal layer 607 is made to coincide with the polarization axis of the first linearly polarized light, the first linearly polarized light component of the incident light is absorbed and the first linearly polarized light component is absorbed. It is possible to realize a variable polarization selection member capable of selecting either the state in which the second linearly polarized light component is transmitted or the state in which all the polarized light components are transmitted.

In the second embodiment, the case where the variable polarization selecting member 600 is arranged on the viewer side of the reflection type polarization selecting member 301 has been described. The variable polarization selection member suppresses unnecessary reflection of external light on the reflection type polarization selection member 301 in the image display state,
It is an important member that contributes to the improvement of the brightness of the mirror by effectively becoming transparent in the mirror state. However, in consideration of various applications, the present invention does not exclude a configuration in which the variable polarization selecting member 600 is not arranged on the viewer side of the reflective polarization selecting member 301. In this case, in the image display state, external light may be reflected by the reflection-type polarization selection member 301 to make it difficult to see the image. However, in the mirror state, the reflection-type polarization selection member and the reflection-type polarization selection member 301 An extremely high reflectance of 80% or more was obtained because there is no member that obstructs the reflection of light. This reflectance is as bright as a mirror having an aluminum thin film formed on a glass substrate, and a mirror having the same brightness as a general mirror can be realized.

(Size of Mirror Area) Here, it is desirable that the display device of each of the first and second embodiments is mainly used by an observer to show his / her face in a mirror state. Find the size of the mirror area. The average height of all faces of an adult male is 234.6 mm, and the average head width is 156.4 mm.
Considering that it is (Handbook of Numerical and Numerical Formulas for Ergonomics; 1992, Gihodo Publishing), the size of the mirror is 117.3 mm in height and width in order for the observer to see the whole face in the mirror without changing the observation position. A size of 78.2 mm or more is required.

In the display device of the present invention, the transmission polarization axis variable unit 400 is used in the first embodiment, and the transmission polarization axis variable unit 400 and the variable polarization selection member 6 are used in the second embodiment.
00, the image display state and the mirror state are switched. Therefore, to realize a mirror area of the above size,
Two transparent substrates 40 that form the transmission polarization axis variable unit 400
Transparent electrodes 403 and 40 respectively formed on
6 and two transparent substrates 60 of the variable polarization selection member 600
1. Transparent electrodes 603 and 60 formed on the electrodes 602 and 602, respectively.
It is desirable that 6 is continuously formed without being chipped in a region having a height of 117.3 mm and a width of 78.2 mm or more. For example, if the transparent electrode is divided and formed within this area range, the part with the transparent electrode functions as a mirror, but the gap of the transparent electrode does not function as a mirror, and the gap becomes streaky. After being observed,
This is because satisfactory performance cannot be obtained as a mirror.

When the display devices of Examples 1 and 2 are used in a mobile device such as a mobile phone or a mobile information terminal, the size of the display device itself is 117.3 mm, which is the height of the mirror size described above. In some cases, the width is less than 78.2 mm. Therefore, instead of reflecting the entire face, it is possible to obtain a mirror size that is suitable for partially applying makeup or checking contact lenses in the eyes. it can. In this case, the size may be such that a quarter of the face is reflected in the mirror. Specifically, it is desirable that the mirror has a height of 58.6 mm and a width of 39.1 mm or more.

Therefore, the transparent electrodes 403 and 406 respectively formed on the two transparent substrates 401 and 402 constituting the transmission polarization axis varying portion 400 and the variable polarization selecting member 600.
The transparent electrodes 603 and 606 formed on the two transparent substrates 601 and 602, respectively, have a height of at least 58.6 m.
It is desirable that the region having a width of m and a width of 39.1 mm or more is continuously formed without chipping.

(Embodiment 3) In the display devices of Embodiments 1 and 2 described above, a liquid crystal display panel having an illuminating device arranged on the back surface is used as the image display section 1000 for emitting the first linearly polarized light as image light. Although the configuration is used, the present invention is not limited to this.

As the image display section 1000 which emits linearly polarized light as image light, a rear projection type display device using a liquid crystal display panel as a two-dimensional optical switch element can be used. The third embodiment uses a rear projection display device as the image display unit 1000 of the display device described in the first embodiment, and the same parts as those in the first embodiment are denoted by the same reference numerals and detailed description thereof will be omitted. .

As shown in FIG. 22, this display device comprises a transmissive screen 703, a projection device 701, and a mirror 702, and the projection light 70 emitted from the projection device 701.
4 is irradiated onto the transmissive screen 703 via the mirror 702. Transmissive screen 703
Includes the reflection-type polarization selection member 300 of Example 1, the transmission polarization axis variable unit 400, and the absorption-type polarization selection member 500.

As the projection device 701, a liquid crystal projection device using a liquid crystal display panel as a two-dimensional optical switch element can be used. The projection device 701 uses, as the projection light, one that emits linearly polarized light in which the polarization states of the respective color lights match. Furthermore, the image light 70 emitted from the projection device 701.
4 is configured to be s-polarized light or p-polarized light with respect to the reflection surface of the mirror 702. This is because the light incident on the reflecting surface generally causes a phase difference between the s-polarized light component and the p-polarized light component on the reflecting surface, so that the s-polarized light or the polarized light other than the p-polarized light enters the reflecting surface. Then, the polarization state changes.

As the mirror 702, an optically isotropic transparent glass on which a reflective metal such as silver or aluminum is deposited can be used.

As shown in FIG. 23, the transmissive screen 703 includes a Fresnel lens sheet 1402, a lenticular lens sheet 1401, and a reflective polarization selection member 300.
A transmission polarization axis variable section 400, and an absorption type polarization selection member 5
00 is arranged in this order. The Fresnel lens sheet 1402 is an optical component having the same function as that of a convex lens, and bends the direction of the chief ray from the projection device 701 to the observer side to expand the suitable viewing range. The lenticular lens sheet 1401 has a function of effectively distributing the limited projection light flux from the projection device 701 to the observation range of the observer. As a result, a bright image can be obtained.

An example of the lenticular lens sheet 1401 that can be used in this embodiment will be described with reference to FIGS. 24 and 25. The lenticular lens sheet 1401 has a plurality of cylindrical lens-shaped lenses 1501 arranged in one direction, and a black stripe 15 is formed on a portion other than a light condensing portion.
02 is provided, and by making the focal position of the lens 1501 the observation surface, ideally, there is no loss of projection light and it is possible to suppress a decrease in the contrast ratio with respect to outside light. There is. Generally, in a lenticular lens sheet, a wide viewing angle can be obtained in the horizontal direction by arranging the generatrix lines so as to be perpendicular to the display surface.

The Fresnel lens sheet 1402 and the lenticular lens sheet 1401 are both provided in the projection device 7.
It is desirable to use a member having a small birefringence, for example, an injection molded product using an acrylic resin, so that the disorder of the polarization of the projection light 704 from 01 is minimized.

As described above, the reflection-type polarization selection member 300 is an important member that functions as a reflection surface of a mirror. Therefore, the reflection-type polarization selection member 300 is a rigid, flat, and optically isotropic transparent substrate so as not to be distorted. For example, it can be configured to be bonded to an injection-molded acrylic resin plate or the like having a thickness of about 3 mm with an adhesive.

The directions of the respective axes of the reflection-type polarization selection member 300, the transmission polarization axis variable section 400, and the absorption-type polarization selection member 500 are emitted from the projection device 701 and transmitted through the transmission screen 70.
The projection light 704 incident on the beam No. 3 is arranged as the first linearly polarized light so as to operate as described in the first embodiment.

Next, the operation of this display device will be described. Here, the case where the absorption type polarization selection member 500 absorbs the first linearly polarized light component and transmits the second linearly polarized light component will be described.

This display device is composed of the same members as in Example 1 except that the rear projection type display device is used as the image display member, and therefore the operation is also the same. That is, when the display device is in the image display state, the image light 704 emitted from the projection device 701 is reflected by the mirror 702 and enters the transmissive screen 703. The image light 704 incident on the transmissive screen 703 is transmitted by the Fresnel lens 1402 and the lenticular lens 1401 through the reflective polarization selection member 300 while being effectively spread in the observation range of the observer, and the transmission polarization axis varying unit 400 is provided. Incident on. When the display device is in the image display state, the image light 704 passing through the variable transmission polarization axis unit 400 is changed from the first linearly polarized light to the second linearly polarized light, and is transmitted through the absorption type polarization selection member 500. Observed by the observer.

On the other hand, the external light traveling from the viewer side to the display device is unpolarized, but when transmitted through the absorption type polarization selection member 500, the first linearly polarized light component is absorbed and the second linearly polarized light component. Only transparent. When the external light transmitted through the absorption type polarization selection member 500 passes through the transmission polarization axis variable unit 400, it changes from the second linearly polarized light to the first linearly polarized light and passes through the reflection type polarization selection member 300. , Fresnel lens 140
2, the lenticular lens 1401, and the mirror 7
It goes toward the projection device 701 through 02 and hardly returns to the observer side.

Therefore, in the image display state, the projection device 70
The image light 704 that has exited from No. 1 and has passed through the Fresnel lens 1402 and the lenticular lens 1401 travels to the observer with almost no loss, so that a bright image can be obtained. Further, since the external light is hardly reflected by the display device, the deterioration of the image quality due to the external light such as glare and deterioration of the contrast ratio does not occur.

When the display device is in the mirror state, the projection device 7
The image light 704 emitted from 01 enters the transmissive screen 703 via the mirror 702. The image light 704 incident on the transmissive screen 703 is the Fresnel lens 1
By the action of 402 and the lenticular lens 1401,
The light is transmitted through the reflective polarization selection member 300 while being effectively spread in the observation range of the observer, and is incident on the transmission polarization axis varying unit 400. When the display device is in the mirror state, the transmission polarization axis variable unit 40
The image light 704 that transmits 0 is transmitted as the first linearly polarized light without changing the polarization axis, and the absorption type polarization selection member 5
Since it is absorbed at 00, it is not observed by the observer.

On the other hand, the external light traveling from the observer side to the display device is unpolarized, but when transmitted through the absorption type polarization selection member 500, the first linearly polarized light component is absorbed and only the second linearly polarized light component. Is transmitted and enters the transmission polarization axis varying unit 400. The external light that has entered the transmission polarization axis varying unit 400 passes through the transmission polarization axis varying unit 400 as the second linearly polarized light without changing the polarization axis, and reaches the reflection type polarization selecting member 300. The reflection-type polarization selection member 300 transmits the first linearly polarized light component and specularly reflects the second linearly polarized light component, so that the reflection-type polarization selection member 300 reflects external light. External light reflected by the reflection type polarization selection member 300 is transmitted through the polarization axis changing unit 400.
The second linearly polarized light is transmitted as is without changing the polarization axis, and the polarization selecting member 500 is also transmitted to the observer.

Therefore, in the mirror state, the image light 704 is absorbed by the absorptive polarization selection member 500 and does not reach the observer, and ideally, the external light incident on the display device reflects half the unpolarized light. Since the light is reflected by the type polarization selection member 300 and is directed toward the viewer side, it functions as a bright mirror.

When the present display device is set to the mirror state, the image of the projection device 701 is displayed dark in the region corresponding to the region to be the mirror state. In this case, since the image light from the projection device 701 hardly leaks and unnecessary light does not go to the observer, there is an effect that a mirror state in which a reflected image with a high contrast ratio is obtained can be realized.

Further, in the above description, the absorption type polarization selecting member 5 is used.
00 shows the case where the second linearly polarized light component is transmitted and the first linearly polarized light component is absorbed.
It is also possible to use one in which 0 transmits the first linearly polarized light component and absorbs the second linearly polarized light component. In this case, when the power consumption of the display device is 0, it can function as a mirror.

Further, in this embodiment, the transmissive screen 70 is used.
As shown in FIG. 23, the Fresnel lens sheet 140
2, the lenticular lens sheet 1401, the reflection type polarization selection member 300, the transmission polarization axis variable section 400, and the absorption type polarization selection member 500 are arranged in this order. However, separately from this configuration, as shown in FIG. 26, the transmissive screen 703 is attached to the Fresnel lens sheet 1402.
The lenticular lens sheet 1401, the reflection type polarization selection member 300, the transmission polarization axis variable section 400, the reflection type polarization selection member 301, and the variable polarization selection member 600 may be arranged in this order. In this case, the rear projection type display device is used for the image display unit 1000 of the display device described in the second embodiment, and the same operation and action as those described in the second embodiment can be obtained.

Further, the transmission type screen 703 of this embodiment.
Of the mirror function part (reflection type polarization selection member 300, transmission polarization axis variable part 400, reflection type polarization selection member 301 and variable polarization selection member 600) and optical system (Fresnel lens sheet 1402 and lenticular lens sheet 1401) The mirror function unit may be detachable from the optical system, and the mirror function unit may be removed when the mirror function is unnecessary.
Alternatively, it is also possible to configure a screen that does not include an image display unit and is independently provided with a mirror function unit, and attach the mirror function screen to an arbitrary display device as needed.

Example 4 A display device of Example 4 of the present invention will be described with reference to FIGS. 27 and 28. The present Example 4 is the transparent substrates 401 and 402 of the display device described in Example 2.
(See FIG. 16), conductive metal linear patterns are formed at a pitch of a few thousand angstroms, and the reflective polarization selection member 301 and the transparent electrode 40 are formed on these metal linear patterns.
3, and the reflective polarization selection member 300 and the transparent electrode 406
The function is also combined. Therefore, the same parts as those described above are designated by the same reference numerals and detailed description thereof will be omitted.

In the fourth embodiment, the transmission polarization axis changing means 40 is used.
Aluminum metal linear patterns are formed on the transparent substrates 401 and 402 of 0 at a pitch of a few thousand angstroms. In this case, the light incident on the metal linear pattern reflects the linearly polarized light component parallel to the longitudinal direction of the line of the metal linear pattern, and transmits the linearly polarized light component in the direction orthogonal thereto, so that the metal linear pattern Functions as a reflective polarization selection member. Further, by electrically connecting a part of these adjacent linear patterns, it is possible to make the potentials the same or substantially the same state, and thus also function as a transparent electrode that transmits a specific linearly polarized light component. be able to. That is, the metal linear pattern has the functions of both the reflective polarization selection member and the transparent electrode. The electrical connection between the adjacent linear patterns is made at a place other than the mirror region such as the peripheral edge so as not to adversely affect the function of the reflection type polarization selecting member.

Here, as shown in FIG. 27, the transmission polarization axis variable portion 400 is provided with a first transparent substrate 401 on which a metal linear pattern 311 and an alignment film 404 made of a polyimide polymer are laminated on the entire surface. , Also metal linear pattern 3
The liquid crystal layer 407 includes a second transparent substrate 402 on which the entire film 10 and the alignment film 405 are formed.

The metal linear patterns 311 and 310 formed on the two transparent substrates 401 and 402, respectively, are connected to a power source via wiring and a switching element (not shown), and are connected to the metal linear patterns 311 and 310. It is configured such that either a state in which no voltage is applied or a state in which a voltage is applied can be selected. That is, there is no potential difference between the metal linear patterns 311 and 310 and no electric field is applied to the liquid crystal layer 407, and the metal linear patterns 311 and 31.
A voltage is applied to 0 and an electric field is applied to the liquid crystal layer 407 so that either state can be selected. In addition, the metal linear patterns 310 and 311 are configured and arranged so that the longitudinal directions of the lines are orthogonal to each other.

The liquid crystal layer 407 includes two transparent substrates 401,
402 are arranged so that the formation surfaces of the alignment films 404 and 410 face each other, and a spacer (not shown) is sandwiched to form a constant gap between the two transparent substrates 401 and 402, and the periphery of this gap is surrounded by the sealing material 410. It is configured by sealing with a frame shape to form a space, and enclosing nematic liquid crystal having a positive dielectric anisotropy in this space.

FIG. 28 is an explanatory diagram of the axial direction of each member of this embodiment. The display of the angle of each axis is based on the position at 3 o'clock in the horizontal direction of the image display surface, and is shown in the counterclockwise direction from here. As shown in FIG. 28, the image display unit 1000
The absorption polarization selection member (polarizing plate) 208 of the TN liquid crystal display panel 200 constituting the
Let be °. Therefore, the transmission polarization axis of linearly polarized light of the metal linear pattern 310 that functions as a reflection type polarization selection member is also 135 °, and the transparent substrate 402 of the transmission polarization axis variable unit 400.
Side and the transparent substrate 401 side have alignment directions of liquid crystal molecule long axes of 135 ° and 45 °, respectively, and a transmission polarization axis of linear polarization of the metal linear pattern 311 functioning as a reflection type polarization selection member is 45 °, and variable polarization selection. Transparent substrate 602 of member 600
And the alignment direction of the liquid crystal molecule major axis on the transparent substrate 601 side is 135 °.

With the above configuration, the display device of the fourth embodiment is
Since the metal linear pattern 310 fulfills the functions of the reflection type polarization selection member 300 and the electrode 406 of the second embodiment, and the metal line pattern 311 fulfills the functions of the reflection type polarization selection member 301 and the electrode 403 of the second embodiment. The display device of Example 4 is
The display device operates in the same manner as the display device of the second embodiment, and the same effect is obtained.

As described in the second embodiment, the reflection-type polarization selection members 300 and 301 are members that function as reflection surfaces when the display device is in the mirror state. For this reason, when the distance between the reflective polarization selecting member 300 and the reflective polarization selecting member 301 becomes large, parallax occurs between the images reflected by the reflective polarization selecting member 300 and the reflective polarization selecting member 301, so that the distance between them is reduced. Should be as small as possible,
Practically, it is desirable that the thickness is 0.11 mm or less. In the fourth embodiment, in particular, the metal linear pattern 310 that functions as the reflection-type polarization selection member 300 and the reflection-type polarization selection member 3 are used.
A liquid crystal layer 407 having a thickness of about several μm and an alignment film 4 having a thickness of less than 1 μm are provided between the metal linear pattern 311 functioning as 01.
Since there are only thin films such as 04 and 410, the distance between them is less than 10 μm. Therefore, an effect that a high-quality mirror that is bright and has no parallax can be realized can be obtained.

Further, the metal linear patterns 310, 311
Since is formed on a flat substrate such as glass, it is possible to realize a mirror that is less susceptible to environmental changes such as temperature and humidity and that is less likely to be distorted due to environmental changes.

Further, in the present invention, the metal linear pattern 31
0 and 311 may be any as long as uniform reflection can be obtained in the visible light range, and the specific structure and pitch of the linear pattern,
The pattern height and the like are not particularly limited. Also,
A metal linear pattern formed of chromium, silver, or the like other than aluminum may be used.

(Fifth Embodiment) In the above first to fourth embodiments, the reflection type polarization selecting member 300 and the transmission polarization axis changing part 400 are provided above the image display section 1000 which emits the first linearly polarized light as image light. And a polarization function selecting member 500, or a reflection function selecting member 300, a transmission polarization axis changing unit 400, a reflection function selecting member 301, and a variable polarization selecting member 600. did. In these cases, the image display unit 1000 can display an image even if the mirror function unit is not arranged. Depending on the purpose of use of the device, the mirror function unit is detachable, and the mirror function is not necessary. Convenience can be improved by removing the functional unit.

However, the present invention is not limited to these. That is, it may be configured such that an image can be displayed when there is a mirror function unit, or a configuration in which a part of the structure of the mirror function unit and the image display member is shared.

The display device of Example 5 will be described with reference to FIG. Since the fifth embodiment has many common parts with the first embodiment (see, for example, FIG. 8), the same members as those of the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted.

This display device is the same as the display device described in the first embodiment, except that the illumination device 100 capable of irradiating the three primary colors of red, green and blue in a time division manner is used.
000 to observer side absorption type polarization selection member (polarizing plate) 2
08 is removed. Therefore, when the mirror function section including the reflection type polarization selecting member 300, the transmission polarization axis changing unit 400 and the absorption type polarization selecting member 500 is removed, the liquid crystal display panel 200 of this embodiment cannot display a clear image. .

The liquid crystal display panel 200 of the present embodiment is the same as the liquid crystal display panel 200 of the first embodiment except that the absorption type polarization selection member (polarizing plate) 208 is removed and the color filter is eliminated to provide a field sequential color display system. The response of the liquid crystal can be speeded up so that it can respond.

Details of the field sequential color display system are described in, for example, JP-A-5-19257 and JP-A-11-52354. The present method realizes a color image display by irradiating the liquid crystal display panel with illumination light of three primary colors in a time division manner and driving the liquid crystal in synchronization with it. That is, the liquid crystal display panel has one
In order to display a frame, it is necessary to sequentially display three sub-frames corresponding to the three primary colors, so that the liquid crystal needs to respond faster. In order to speed up the response of the liquid crystal so as to correspond to the field sequential color display system, for example, in the case of using the TN mode, a liquid crystal having a large birefringence Δn is used in order to satisfy the conditions of the above waveguide, and the thickness of the liquid crystal layer 207 is set. The thickness may be as thin as about 2 μm.

In the present embodiment, the case of the TN mode will be described below, but the liquid crystal display panel of the present invention is not limited to the above structure as long as it has a structure capable of obtaining a response characteristic corresponding to the field sequential color display system. Not something.

The illuminating device 100 includes a light guide body 193 made of a transparent medium, and red, green, and red light disposed on the end surface of the light guide body 193.
A light source 190 that emits light of the three primary colors of blue, and a light guide 19
3 is composed of a polarization maintaining reflection sheet 192 arranged on the back surface of No. 3 and a polarization maintaining diffusion section 191 arranged on the front surface of the light guide 193.

As a light source 190 for emitting light of the three primary colors of red, green and blue, an LED (Light Emitting Dio) integrated with three chips for emitting the light of the three primary colors
de) can be used. Such an LED is sold by Nichia Corporation.

The light guide 193 is made of a transparent acrylic resin, and has a structure in which the light incident from the end face is confined inside by total reflection, and the reflection angle of the light propagating inside is changed to the liquid crystal display panel 200 side. The back surface (the surface opposite to the liquid crystal display panel 200) is provided with a tilted reflection surface 194 composed of a large number of uneven surfaces or steps having a fine tilted surface that emits light. This is to maintain the polarization state of the light incident on the light guide 193 from the liquid crystal display panel 200 side for the reason described later.

The inclined reflection surface 194 is preferably a mirror reflection surface made of a metal thin film of aluminum, silver or the like, or a dielectric multilayer film, but is not limited to these.
Even if such a special reflection member is not provided, the required reflection function is satisfied by the difference in refractive index between air and acrylic resin.

Here, the inclined reflecting surface 194 has an average pitch of 200 μm, an average height of 10 μm, and an average inclination angle of 41 °. It should be noted that the height of the inclined reflection surface 194 is continuously changed so as to be low near the light source 190 and high in a location distant from the light source 190, or the pitch or the inclination angle of the inclined reflection surface 194 is changed from the light source 190. Therefore, the uniformity of the light emitted from the light guide 193 may be increased by continuously changing the thickness of the light guide 193 or by reducing the thickness of the light guide 193 as the distance from the light source 190 increases.

The shape of the light guide 193 is not limited to this shape as long as it substantially maintains the polarization state of the light entering the light guide 193 from the liquid crystal display panel 200 side.

The polarization maintaining reflection sheet 192 is formed by forming a reflection surface for maintaining the polarization state on a substrate such as a glass plate, a resin plate, or a resin film, and returns from the liquid crystal display panel 200 side to the illuminating device 100. It has a function of reflecting light to the liquid crystal display panel 200 side while maintaining its polarization state again. The reflecting surface that maintains the polarization state described here is a reflecting surface that reflects linearly polarized light as it is, and circularly polarized light as circularly polarized light with its rotation direction reversed, at least for vertically incident light. That is. Specifically, as a reflecting surface, a base material coated with a metal thin film such as Al or Ag, or a mirror-like reflecting surface of a dielectric multilayer film configured to obtain a high reflectance in the wavelength band of the light source light To use.

The polarization maintaining / diffusing section 191 is for uniformizing the emission angle distribution and the in-plane luminance distribution of the light emitted from the light guide body 193, and the polarization state of the light passing therethrough is substantially maintained. To do. As the polarization maintaining / diffusing section 191, a plurality of spherical transparent beads are densely arranged in a plane on an optically isotropic transparent substrate and fixed with a transparent resin, or on an optically isotropic transparent substrate. Hologram diffusing plate formed on the surface, or SPIE, Vol.1536, Optical Materials Techno
logy for Energy Efficiency and Solar Energy Conver
LCG (light cont described in sion X (1991), pp138-148.
rol glass) or the like can be used.

FIG. 30 is an explanatory diagram of the axial direction of each member of this embodiment. As shown in the figure, when a TN liquid crystal display panel is used as the liquid crystal display panel 200, the transmission polarization axis of linearly polarized light of the polarizing plate 209 is usually 45 ° or 135 ° in order to obtain horizontal symmetry of the viewing angle characteristics. (45 ° in this embodiment). The liquid crystal alignment axis on the transparent substrate 202 side and the liquid crystal alignment axis on the transparent substrate 201 side are 45 ° and 1 respectively.
35 °, the transmission polarization axis of the linearly polarized light of the reflection-type polarization selection member 300 is 135 °, and the alignment directions of the liquid crystal molecule long axes on the transparent substrate 402 side and the transparent substrate 401 side of the transmission polarization axis varying unit 400 are 135 °. And the transmission polarization axis of the linearly polarized light of the absorption type polarization selection member 500 is 45 °.

Next, the operation of this embodiment will be described. Light source 19
The light emitted from 0 enters the light guide 193,
3 is propagated while repeating total reflection. Light guide 19
Of the light propagating in 3, the light reaching the inclined and inclined surface 194 changes its traveling direction and is emitted from the surface side of the light guide body 193. The light emitted from the light guide 193 is polarized maintaining / diffusing section 19
After the emission angle distribution and the in-plane brightness distribution are made uniform by 1, the liquid crystal display element 200 is irradiated with the light.

Of the light emitted to the liquid crystal display panel 200, the linearly polarized light transmitted through the polarizing plate 209 is the liquid crystal layer 20.
Although it passes through 7 and enters the reflection type polarization selection member 300,
At this time, the polarization state of the light passing through the liquid crystal layer 208 can be changed by the voltage applied to the liquid crystal layer 207. Therefore, the voltage corresponding to the image information transmitted from the image information generating unit is applied to the transparent electrodes 2 on the transparent substrates 202 and 201.
03 and 205, and by applying an electric field to the liquid crystal layer 207, the polarization state of light passing through the liquid crystal layer 207 is changed,
By controlling the amount of light that passes through the reflective polarization selection member 300, an optical image composed of linearly polarized light can be formed. That is, in Example 1, the absorption type polarization selecting member (polarizing plate) 208 arranged on the viewer side of the liquid crystal display panel 200.
The reflection type polarization selection member 300 of the present embodiment also has the above function.

The image light transmitted through the reflection type polarization selecting member 300 enters the transmission polarization axis varying section 400. When the present display device is in an image display state, the transmission polarization axis variable unit 400 is in a state in which no voltage is applied to the liquid crystal layer 407 which constitutes the transmission polarization axis variable unit 400, that is, in an off state.

If the linearly polarized light component transmitted through the reflection type polarization selection member 300 is the first linearly polarized light component and the linearly polarized light component whose polarization axis is orthogonal to this is the second linearly polarized light component, then the transmitted polarized light axis is The image light passing through the variable unit 400 is the first
From the linearly polarized light of No. 2 to the second linearly polarized light. The image light transmitted through the transmission polarization axis varying unit 400 enters the absorption type polarization selecting member 500. The absorption-type polarization selection member 500 is the first
Since the linearly polarized light component of is absorbed and the second linearly polarized light component is transmitted, the image light 3001 converted into the second linearly polarized light by the transmission polarization axis varying unit 400 is the absorption polarization selection member 50.
It is transmitted through 0 and is observed by an observer.

When the present display device is in the mirror state, the transmission polarization axis varying section 400 applies an electric field to the liquid crystal layer 407 constituting the transmission polarization axis varying section 400 to turn it on. At this time, since the display device does not have the absorption polarization selection member (polarizing plate) 208 provided as the absorption polarization selection member in the above-described embodiment, the lighting device 1
When 00 is turned on, the image light leaks to the observer side, and the contrast ratio of the reflected image is lowered, so that an easy-to-see mirror cannot be realized. Therefore, the lighting device 100 is turned off when it is in the mirror state. In the case of the present embodiment, by using the LED as the light source 190 of the illuminating device 100, it is possible to turn on and off at high speed, so that the mirror state and the image display state can be switched at such a high speed that the observer does not feel stress.

On the other hand, when the external light traveling from the observer side to the display device passes through the absorption type polarization selecting member 500, the first linearly polarized light component is absorbed and only the second linearly polarized light component is transmitted and transmitted. The light enters the polarization axis changing unit 400. External light that has entered the transmission polarization axis varying unit 400 passes through the transmission polarization axis varying unit 400 as the second linearly polarized light without changing the polarization axis, and reaches the reflective polarization selection member 300. The reflection-type polarization selection member 300 transmits the first linearly polarized light component and specularly reflects the second linearly-polarized light component, so that the external light 3002 is reflected by the reflection-type polarization selection member 300. Reflective polarization selection member 30
The external light 3002 reflected at 0 is transmitted through the transmission polarization axis variable unit 400 as the second linearly polarized light without changing the polarization axis, and is further transmitted through the absorption type polarization selection member 500 toward the observer.

Therefore, in the display device of this embodiment, since the illumination device is turned off in the mirror state, the image light does not reach the observer, and ideally, half of the unpolarized light out of the external light. Since the light is reflected by the reflective polarization selection member 300 and is directed toward the viewer side, it functions as a bright mirror.

In addition to this, this embodiment has the following unique effects.

FIG. 31 is a diagram for explaining the effect peculiar to this embodiment. Here, if the linearly polarized light component that passes through the reflective polarization selection member 300 is the first linearly polarized light component and the linearly polarized light component whose polarization axis is orthogonal to this is the second linearly polarized light component, the polarizing plate 209 is the second linearly polarized light component. The linearly polarized light component of is transmitted.

In this display device, as described above, the lighting device 10 is used.
Of the light emitted from 0 to the liquid crystal display panel 200, the second linearly polarized light (perpendicular to the plane of the drawing in the figure) that has passed through the polarizing plate 209 passes through the liquid crystal layer 207 and then the reflective polarization selection member 3
Incident on 00. At this time, the polarization state of the light passing through the liquid crystal layer 207 is modulated according to the image information, and the light 3100 passing through the bright display area is changed from the second linearly polarized light to the first linearly polarized light and reflected. The light passes through the mold polarization selection member 300 and goes to the observer.

On the other hand, the light 3101 passing through the dark display region is incident on the reflection type polarization selection member 300 as the second linearly polarized light, and therefore is reflected by the reflection type polarization selection member 300 and does not reach the observer. The light 3101 reflected by the reflective polarization selection member 300 remains as the second linearly polarized light again in the liquid crystal layer 207.
Then, the light passes through the polarizing plate 209 and returns to the illumination device 100. At this time, the polarization maintaining / diffusing section, the light guide, and the polarization maintaining / reflecting sheet 192 that form the illumination device 100 are the liquid crystal display element 20.
The light returning from the 0 side is transmitted or reflected while substantially maintaining the polarization state. Therefore, the light 3101 reflected by the illuminating device 100 and traveling toward the liquid crystal display panel 200 is almost second linearly polarized light, and is incident on the liquid crystal layer 207 with almost no absorption by the polarizing plate 209. Of the light 3101 incident on the liquid crystal layer 207, the light incident on the bright display region is changed from the second linearly polarized light to the first linearly polarized light, transmitted through the reflective polarization selection member 300, and observed. It can be effectively used as image light for people.

In other words, the light incident on the dark display area is initially reflected by the reflection type polarization selection member 300 and therefore does not become image light. However, the light reflected by the reflective polarization selection member 300 is directed to the lighting device 100, is reflected in the lighting device 100 in a state in which the polarization state is substantially maintained, and heads again to the liquid crystal display panel 200. Therefore, the light is reused without significant loss, and the brightness of the bright display area is improved.

Generally, the light transmittance of the color filter is as low as about 25%, but since the color filter is not used in this embodiment, the light can be reused more efficiently.

Generally, in the liquid crystal display panel, the brightness of white display does not change between the case where the entire screen is displayed in white and the case where part thereof is displayed in white. On the other hand, CRT (Cathode Ra
y Tube) is said to be able to brighten the white display by about four times when displaying 15% of the screen in white, compared to displaying the entire screen in white. This means that, for example, when displaying a partially bright image such as sunlight, the CRT
Then, it appears as a difference in image quality that an image more powerful than that of a liquid crystal display panel is obtained.

In the display device of this embodiment, the brightness of the bright display region can be improved by reusing the light incident on the dark display region. Therefore, compared with the case where the entire screen is displayed in white, When is displayed in white, the white display can be brightened. Therefore, a powerful image close to a CRT can be obtained.

Further, when the present display device is used as a display portion of a mobile device such as a mobile phone, the following effects can be obtained. This display device functions as a color display device by the field sequential color display method when the lighting device is turned on, but when the lighting device is turned off, it functions as a reflection type liquid crystal display panel for bright monochrome display because there is no color filter. Can be made. Here, in the case of color display, it is necessary to display at least three subframes of red, green, and blue in order to display one frame, but in the case of monochrome display, it is not necessary to provide subframes so that driving is possible. The frequency can be reduced to one third or less. If the drive frequency can be reduced to one third or less, the power consumption can be significantly reduced. Therefore, if the drive frequency switching unit is provided so that the drive frequency can be changed between the color display state and the monochrome display state. , The power consumption in the monochrome display state can be significantly reduced.

That is, when the present display device is used as a display unit of a portable device, when the device is in use, the lighting device is turned on to bring the device into a color display state, which gives a powerful and bright and high-quality image. On the other hand, when the device is on standby, the lighting device is turned off, the driving frequency is lowered, and the monochrome display state is set, whereby the power consumption can be extremely reduced. Therefore, for example, the standby time of the mobile phone can be lengthened, and the usage time of the battery of the mobile device can be increased.

Furthermore, as described above, these effects can be achieved while the image display state and the mirror state can be switched without deteriorating the performance of each other. Further, in this embodiment, a metal linear pattern is formed on the transparent substrate on the viewer side of the liquid crystal display panel, and a part of each pattern is electrically connected, so that the metal linear pattern is transparent. A configuration may be used in which the function of the electrode and the function of the reflection-type polarization selection member are combined.

(Embodiment 6) Another embodiment of the present invention will be described below with reference to the drawings.

A display device with a function for switching to a mirror state according to the sixth embodiment of the present invention will be described with reference to FIG. The display device according to the first embodiment is the image display unit 1000.
As a reflective liquid crystal panel 3000, the same members as those in the above-described embodiment are designated by the same reference numerals and detailed description thereof will be omitted.

The display device of Example 6 includes a reflective liquid crystal element 3000, which is a transparent substrate 3030.
And a reflective substrate 3100 having a reflective portion, and a liquid crystal layer 3130 sealed in a space formed by pasting these two substrates together through a spacer such as beads and sealing with a frame-shaped sealing material. In addition, the transparent substrate 30
Reference numeral 30 denotes a retardation plate 3020, a reflection type polarization selection member 30.
0, the transmission polarization axis variable unit 400, and the absorption type polarization selection member 500 are arranged so as to overlap each other.

As the reflecting substrate 3100, a flat insulating substrate such as glass or polymer film is used, and a glass substrate having a thickness of 0.7 mm is used here. On the reflective substrate 3100, a scanning electrode and a signal electrode, and a switching element 3110 that is provided at the intersection of these, for example, a TFT (Thin Film Transistor) or the like, an insulating layer 3090 formed on these, and an insulating layer 3090 formed on the insulating layer. Formed and insulating layer 309
There are provided pixel electrodes 3070 that are subdivided into a matrix and that are electrically connected to the switching elements through through holes 3120 that are opened at 0.

The pixel electrode 3070 is made of a metal having a high reflectance such as aluminum and silver, and functions as a diffuse reflection portion due to the shape of the fine recesses or protrusions formed on the insulating layer 3090. Pixel electrode 3070
The upper layer is an alignment film 3060 made of a polyimide-based polymer.
Are formed over the entire surface, and the surface thereof is subjected to a surface treatment by a rubbing method or the like.

As the transparent substrate 3030, an optically isotropic and flat transparent insulating substrate such as glass or polymer film can be used. Here, a glass substrate having a thickness of 0.7 mm was used. The transparent substrate 3030 has a color filter 30 at a position corresponding to the pixel electrode 3070 of the reflective substrate 3100.
40 is formed. The color filter 3040 is one in which three types of color filters having transmission spectra corresponding to the three primary colors of red, green, and blue are alternately repeated and arranged at a position corresponding to the pixel electrode 3070.

Further, a black matrix may be formed at positions corresponding to the pixels of the color filter 3040 to suppress light leaking from the pixels. A transparent electrode 3050 made of ITO is entirely formed on an upper layer of the color filter 3040 through an overcoat layer (not shown), and an alignment film 3210 made of a polyimide polymer is entirely formed on an upper layer of the transparent electrode 3050. Then, the surface is subjected to a surface treatment by a rubbing method or the like.

The transparent substrate 3030 and the reflective substrate 3100 are
The transparent electrode 3050 formation surface and the reflection electrode 3070 formation surface are bonded so as to face each other. At this time, by disposing bead spacers between both substrates and sealing the peripheries of the display surfaces of both substrates with a frame-shaped sealing material, a space having a certain gap is formed.

A liquid crystal composition obtained by adding a small amount (0.1 to 0.2%) of a chiral agent to a nematic liquid crystal having a positive dielectric anisotropy is sealed and sealed in the gap between the substrates 3030 and 3100. Layer 3130 was constructed. Δn of the liquid crystal layer 3130
d was 0.365 μm. The direction of the liquid crystal molecule major axis of the liquid crystal layer 3130 is the transparent substrate 3030 and the reflective substrate 3100.
The orientation direction is defined by the surface treatment (orientation treatment) performed on the orientation film 3210 and the orientation film 3060 formed above, and the two substrates are continuously twisted by a predetermined angle.

A retardation plate 3020 is laminated on the transparent substrate 3030. As the retardation plate 3020, for example, a uniaxially stretched polymer film such as polycarbonate, polysulfone, or polyvinyl alcohol can be used. Here, as the retardation plate 3020, a retardation plate made of polycarbonate having Δnd of 0.18 μm was used.

The transparent substrate 3030, the retardation plate 3020, the reflection type polarization selecting member 300, the transmission polarization axis variable part 400 and the absorption type polarization selecting member 500 were adhered by an acrylic adhesive so as to be optically coupled.

FIG. 33 is a diagram showing the axial directions of the respective members of the display device when viewed from the observer side. The angle of each axis is based on the position of the image display surface at 3 o'clock in the horizontal direction, and is shown as an angle counterclockwise from here. As shown in FIG. 33, in the display device, the liquid crystal alignment axis on the reflective substrate 3100 side is 295 °, the azimuth angle of the liquid crystal alignment axis on the transparent substrate 3030 side is 65 °, the slow axis of the retardation plate 3020 is 135 °, and the reflective type. The transmission polarization axis of the linearly polarized light of the polarization selection member 300 is 30 °, and the transparent substrate 40
The liquid crystal orientation axis on the 2 side was 30 °, the liquid crystal orientation axis on the transparent substrate 401 side was 120 °, and the transmission polarization axis of the linearly polarized light of the absorption type polarization selection member 500 was 120 °.

Next, the operation of this display device will be described with reference to the drawings. In the present embodiment as well, as in the first embodiment and the like, the linearly polarized light component transmitted through the reflective polarization selection member 300 is defined as the first linearly polarized light component, and the linearly polarized light component whose polarization axis is orthogonal to the second linearly polarized light component Of the linearly polarized light component.

FIG. 34 shows the case where this display device is in the mirror state. In this case, external light 3 from the viewer side to the display device 3
002 is non-polarized light, but when transmitted through the absorption polarization selection member 500, the first linearly polarized light component is absorbed and only the second linearly polarized light component is transmitted and enters the transmission polarization axis variable unit 400. External light 300 incident on the transmission polarization axis variable unit 400
Reference numeral 2 denotes the transmission polarization axis variable unit 400, which transmits the second linearly polarized light as it is without changing the polarization axis, and the reflection type polarization selection member 3
To 00. The reflection-type polarization selection member 300 transmits the first linearly polarized light component and specularly reflects the second linearly-polarized light component, so that the external light 3002 is reflected by the reflection-type polarization selection member 300. External light 3002 reflected by the reflective polarization selection member 300
Is transmitted through the transmission polarization axis varying unit 400 as the second linearly polarized light without changing the polarization axis, and is also transmitted through the absorption type polarization selection member 500 toward the observer.

That is, when the display device is in the mirror state, the external light 3002 does not reach the reflective liquid crystal element 3000,
The light is reflected by the reflection type polarization selection member 300, and functions as a bright mirror toward the viewer side.

When the present display device is set to the mirror state, the reflection type liquid crystal element 3000 can be set in the non-display state so that unnecessary power is not consumed.

35 and 36 show the case where the display device is in the image display state. The image display state will be described with reference to FIG. In this case, the external light 3002 traveling from the viewer side (the left side in the drawing) to the display device is unpolarized, but when passing through the absorption polarization selection member 500, the first linearly polarized light component is absorbed and the second linearly polarized light component is absorbed. Only the linearly polarized light component is transmitted. External light 300 transmitted through the absorption type polarization selection member 500
When 2 passes through the transmission polarization axis varying unit 400, it changes from the second linearly polarized light to the first linearly polarized light, passes through the reflective polarization selecting member 300, and enters the reflective liquid crystal element 3000. The first linearly polarized light that has entered the reflective liquid crystal element 3000 passes through the retardation plate 3020 and the liquid crystal layer 3130, is reflected by the pixel electrode 3070, passes through the liquid crystal layer 3130 and the retardation plate 3020 again, and is of the reflection type. The light enters the polarization selection member 300. At this time, the polarization state of the light passing through the liquid crystal layer 3130 changes depending on the voltage applied to the liquid crystal layer 3130.

Here, the switching element 3110 is connected to the pixel electrode 3070 through the through hole 3120, and by switching the voltage applied to the pixel electrode 3070, the transparent electrode 3050 and the pixel electrode 3070.
The voltage applied to the liquid crystal layer 3130 sandwiched between and can be controlled for each pixel. Therefore, a voltage corresponding to image information is applied to the transparent electrode 3050 and the pixel electrode 3070,
By applying a predetermined voltage to the liquid crystal layer 3130, the polarization state of light passing through the liquid crystal layer 3130 can be controlled, and the amount of light passing through the reflective polarization selection member 300 can be controlled to form an optical image.

FIG. 35 shows a case of bright display. In the configuration of this embodiment, when no voltage is applied to the liquid crystal layer 3130, the light incident on the reflective liquid crystal element 3000 is reflected as the first linearly polarized light and is transmitted through the reflective polarization selection member 300 again. And enters the transmission polarization axis varying unit 400. When the light incident on the transmission polarization axis varying unit 400 is transmitted therethrough, the light changes from the first linearly polarized light to the second linearly polarized light, passes through the absorptive polarization selection member 500, and is illuminated toward the observation side. Will be displayed.

FIG. 36 shows the case of dark display. In the structure of this embodiment, when a predetermined voltage is applied to the liquid crystal layer 3130,
The first linearly polarized light that has entered the reflective liquid crystal element 3000 is reflected by the reflective liquid crystal element 3000, and when it is emitted, it becomes second linearly polarized light and again enters the reflective polarization selection member 300. Second re-incident on the reflection type polarization selection member 300
The linearly polarized light of is reflected by the reflection type polarization selection member 300 and enters the reflection type liquid crystal element 3000 again. The second linearly polarized light that has entered the reflective liquid crystal element 3000 is reflected by the reflective liquid crystal element 3000 and becomes the first linearly polarized light when emitted.

However, at this time, the reflective liquid crystal element 3000
On the transparent substrate 3030, three types of color filters 3040 having different transmission spectra corresponding to the three primary colors of red, green and blue are alternately and repeatedly formed. Therefore, for example, as shown in the figure, the light that first enters the reflective liquid crystal element 3000 is not reflected by the green color filter 30.
If the light is incident on and transmitted through 40G, and is incident on the blue color filter 3040B at the second incidence, most of the light is absorbed and dark display is performed. In addition, the reflective liquid crystal element 3
Even if the light incident on 000 passes through the color filters of the same color, a dark display is obtained because the light passes through the color filters twice in the forward and backward paths and a total of four times. That is, in the structure of this embodiment, the color filter is used as a member for improving the darkness of dark display.

In order to realize a sufficiently dark dark display, it is desirable to pass through color filters of different colors when passing through the color filters four times. For this reason, it is desirable that the color filters are arranged in a delta arrangement rather than in a stripe shape so that the colors of the color filters adjacent to each other in the vertical and horizontal directions are different as much as possible.

The thicker the transparent substrate 3030 of the reflective liquid crystal element 3000, the more the reflective polarization selecting member 30.
The light reflected at 0 easily passes through different positions of the reflective liquid crystal element 3000 and passes through color filters of different colors. Therefore, it is desirable that the transparent substrate 3030 be as thick as possible within a practical range.

As described above, according to the display device of the sixth embodiment, the reflection type polarization selecting member 300 includes the transmission polarization axis changing section 4.
By controlling the polarization state by 00, the state that is effectively transparent and the state that functions as a mirror can be switched. Therefore, in the image display state, a bright image can be obtained by effectively setting the reflective polarization selection member 300 in a transparent state. Further, even in a bright environment, there is no deterioration of image quality such as reflection when using a half mirror, a reduction in contrast ratio, and a reduction in brightness of image light. That is, the switching between the image display state and the mirror state can be realized without deteriorating the performance of each other.

By the way, in this embodiment, a case has been described in which the reflective liquid crystal panel 3000 is not provided with the polarizing plate functioning as the absorption type polarization selecting member. This is because it is important to reduce the number of members that absorb light as much as possible in order to improve the brightness of the image display state. In particular, since the image is originally dark in a reflective liquid crystal display panel capable of color display, the image may be further darkened by the absorption type polarization selection member, the transmission polarization axis variable unit, and the mirror function unit including the reflection type polarization selection member. This is because the situation is unacceptable. Therefore, for example, the reflective liquid crystal element 3000 may be provided with a polarizing plate for applications such as frequent use in places with strong outdoor light such as outdoors.

Furthermore, in the case of a polarizing plate having a high transmittance with a transmittance of a predetermined linearly polarized light component close to 100%, the reflective liquid crystal element 3000, that is, the reflective polarization selecting member 300.
It is desirable to arrange the transmission polarization axis of the polarizing plate so as to be aligned with the transmission polarization axis of the reflection-type polarization selection member between the transparent substrate 3030 and the transparent substrate 3030 because the brightness of the image is hardly reduced. in this case,
In general, a polarizing plate having a high transmittance has a low degree of polarization, so that a reflection type liquid crystal panel alone cannot display an image with a sufficient contrast ratio. However, if a polarizing plate having a high degree of polarization is used as the absorption type polarization selection member 500, display performance is improved. There is no problem. rather,
When displaying an image, there is an advantage that a darker dark display can be realized and an image with a high contrast ratio can be realized.

That is, when a reflection type liquid crystal display panel having a reflection part built in a substrate is used as the image display member, a polarizing plate having a high degree of polarization is used as the absorption type polarization selection member and the reflection type polarization selection of the image display member is used. When a polarizing plate having a low degree of polarization and a high transmittance is used for the absorption type polarization selection member arranged on the member side, both the brightness of an image and a high contrast ratio are compatible.

In this embodiment, the case of using the reflection type liquid crystal display panel has been described. However, an opening portion is provided in a part of the pixel electrode functioning as a reflection member so that the pixel electrode can be partially transmitted so that the reflection display can be realized. The transparent display may also be used.
In this case, it is preferable to dispose a quarter wave plate, a polarizing plate, and an illuminating device on the back surface side of the reflecting member. According to such a configuration, it is possible to display an image by turning on the lighting device even in a situation where external light is weak such as at night or in a building.

(Embodiment 7) Another embodiment of the present invention will be described with reference to the drawings.

The display device with a function for switching to the mirror state according to the seventh embodiment will be described with reference to FIG. 38 is a schematic diagram showing the appearance of a mobile phone using this display device. FIG. 38 (a) shows an image display state and FIG. 38 (b) shows a mirror state. 39 shows an example of a circuit configuration of a mobile phone using the display device shown in FIG.

The mobile phone 810 of the seventh embodiment includes at least an antenna 811, a speaker 812, a button 814 such as a numeric keypad, a microphone 815, a mirror state / image display state changeover switch 813, and an image display section 1000 and a mirror of this display device. And a functional unit 801.

The mobile phone 810 of the seventh embodiment comprises a communication section 10 for realizing a telephone function, an operation section 20 for inputting an operation, and a display section 30 according to the present invention capable of switching between an information display state and a mirror state. ing. The communication unit 10 includes an antenna 81.
1 is connected to 1 to perform transmission / reception processing of a communication signal, input / output of voice information through a microphone 815 and a speaker 812, and perform signal conversion processing between the voice information and the transmission / reception signal. A signal processing unit 822 and a communication control unit 823 that controls a transmission / reception operation according to an input operation instruction are provided. The operation unit 20 is
Numeric keypad / button 814 for inputting various operations and changeover switch 813 for switching between information display state and mirror state
With.

The display unit 30 includes an image display unit 1000 that includes an illuminating device 836 and displays information, and a display control unit 831 that receives control instructions from the communication unit 10 and the operation unit 20 and controls the operation of the display unit. A drive circuit unit 832 for driving the image display unit 1000 in response to a control signal from the display control unit 831; and a mirror function unit 801 which is arranged on the image display unit 1000 and selectively realizes a mirror state and a transparent state. An applied voltage generation unit 834 that generates at least an applied voltage to the transmission polarization axis variable unit 400 of the mirror function unit 801, and a mirror function unit 801 according to an instruction from the changeover switch 813 or a communication state.
Mirror control unit 833 for controlling the applied voltage generation unit 834 so as to switch the state of the display, the display control unit 831 and the mirror control unit 8
A lighting switch 835 that turns on and off the lighting device in accordance with a control signal from 33.

In this display device, as shown in FIG. 37, the area of the mirror function part 801 including the reflection type polarization selecting member 300, the transmission polarization axis changing part 400 and the absorption type polarization selecting member 500 is shown in the image of the image display part 1000. The display area 1001 is larger than the area of the display area 1001 and basically has the same configuration and functions as those of the first embodiment except for the above.

The reflection type polarization selection member 30 of the mirror function unit 801.
0 is fixed to the substrate that constitutes the variable transmission polarization axis unit 400 by a transparent adhesive material. Further, a frame 810F of a mobile phone is provided between the mirror function unit 801 and the image display unit 1000 so that the reflection-type polarization selection member 300 does not come into contact with the image display unit 1000 at a halfway point and an interference fringe is generated.
A constant space 801S is provided by using the convex portion 801a formed in the above as a spacer.

Here, as described above, when the display device is in the mirror state, it does not display information such as data there,
If it is specified that the observer's face is mainly used for observing and observing his / her face, the size of the mirror is preferably 58.6 mm in height and 39.1 mm in width or more as described above. However, the image display member cannot be made too large because there is a problem that power consumption increases when the image display unit is enlarged. On the other hand, the mirror function section does not cause any problem by increasing its area. Therefore, in the seventh embodiment, the area of the mirror function portion is configured to be as large as possible regardless of the area of the image display region 1001.

Further, the mirror function section 801 of this display device is capable of effectively switching between the transparent state and the mirror state by controlling the polarization state by the transmission polarization axis varying section 400. Therefore, even if the large-area mirror function unit 801 is placed on a design such as a logo mark, it does not affect the base when it is effectively in a transparent state. I don't know.

Next, the operation of the mobile phone 810 of this embodiment will be described with reference to FIG.

As shown in FIG. 38 (a), when the mobile phone displays an image even when it is in use or in standby, the mirror function section 801 is effectively in a transparent state, and a bright image is displayed. The display is obtained, and the logo mark and design around the image display part are also visible. on the other hand,
In the mirror state, as shown in FIG. 38 (b), a mirror surface larger than that of the image display section appears and a practical mirror can be obtained.

Since the display device of the seventh embodiment is configured so that the mirror state and the image display state can be performed with one touch by the changeover switch 813, the operability is high. The changeover switch 813 is configured to switch between a case where an AC voltage of about ± 3 V to ± 5 V is applied to the pair of electrodes sandwiching the liquid crystal layer of the transmission polarization axis varying unit 400, and a state where the pair of electrodes are short-circuited. . Furthermore, in conjunction with the changeover switch 813,
In the case of the mirror state, the image display unit 1000 is set to the non-display state and the illumination device is also turned off to reduce the power consumption.

[0289] Further, since the switching from the mirror state to the image display state is automatically switched by an incoming call, the incoming call information can be viewed without a switch operation, further improving the convenience of the user. .

When the TN liquid crystal element is used as the transmission polarization axis variable unit 400, the mirror state and the image display state are switched at a high speed of several tens of milliseconds, which does not inconvenience the user.

Further, although the area of the mirror function section 801 is made larger than the area of the image display area 1001 in the present embodiment, in the present invention, the area of the mirror function section 801 or the area capable of realizing the mirror state and the image display area. The ratio of 1001 or the area of the transmissive / reflective image display member is not limited to this example. Of course, both areas may be substantially the same as in the above embodiments, or the area of the mirror function part may be made smaller, or the mirror function part may be overlapped with the image display part except for a specific region. Is also possible.
For example, it is possible to have a structure in which only the display portion of the mark is not covered with the mirror function portion so that only the mark indicating whether the mobile phone is in the communication enabled state can be always checked.

Further, although the case where the entire surface of the mirror function section is set to the mirror state has been described in the present embodiment, for example, the mirror area of the mirror function section is divided into a plurality of areas, and the mirror state and image display are performed for each divided area. It is possible to adopt a configuration in which the state is switched.
More specifically, for example, the voltage application to the transmission polarization axis variable portion or the variable absorption polarization selection member is performed for each divided area, or the pixel electrodes are arranged in a matrix to arrange arbitrary pictures or characters in a mirror state. Can be displayed.

(Embodiment 8) Another embodiment of the present invention will be described with reference to the drawings.

The eighth embodiment of the present invention will be described with reference to FIGS. 40, 41 and 42. In the eighth embodiment, the same parts as those in the seventh embodiment are designated by the same reference numerals and detailed description thereof will be omitted.

The configuration of the eighth embodiment is a detachable mirror function unit that allows a user to add a mirror function to an existing mobile phone. As shown in FIG. 41, the detachable mirror function unit 801 is configured to include a reflective polarization selection member 300, a transmission polarization axis variable unit 400, and an absorption polarization selection member 500, which are transparent to each other. It is adhesively fixed by the material. A transparent protective member 500P made of a film or a thin acrylic plate is attached to the surface of the absorption type polarization selecting member 500 by a transparent adhesive material. A sponge-like frame-shaped spacer 843 having elasticity is provided on the peripheral portion of the reflection-type polarization selection member 300, and the double-sided tape 8 is provided on the surface of the spacer 843 as necessary.
44 is provided. The spacer 843 is arranged so that the reflective polarization selection member 300 does not come into contact with other members and maintains a constant space when the mirror function unit is attached to a device such as a mobile phone. This prevents the reflection-type polarization selection member 300 and other members from coming into contact with each other and causing interference fringes or the like.

The transmission polarization axis varying section 400 is connected to the mirror function driving section 840 via the wiring connected to the transparent electrodes formed on the transparent substrate forming the transparent polarization axis varying section 400.

As shown in FIG. 42, the mirror function driving section 840
Is a power source 845 composed of a small battery and a changeover switch 846.
And the transmission polarization axis variable unit 4 by the power supply from the power source 845.
And a drive circuit 847 which generates a voltage for driving 00, and which operates the changeover switch 846 to drive the transmission polarization axis variable section 400 to switch the mirror function section between a mirror state and a transparent state.

When the mirror function unit 801 is attached to the mobile phone 810, the wiring between the mirror function unit 801 and the mirror function drive unit 840 is such that the strap attachment unit 841 of the mobile phone is installed.
Attached via wiring, wiring 842 and mirror function drive unit 84
It can be configured to be attached as if 0 is a strap. In this case, even if the mirror function driving section 840 is pulled by mistake, the force is stopped at the strap attaching section 841 of the mobile phone, and there is an advantage that the mirror function section is not directly applied.

Example 9 A display device of Example 9 of the present invention will be described with reference to FIG.

The display device of Example 9 in FIG. 43 uses an organic electroluminescence (EL) display panel 900 as an image display unit for emitting image light, and is the same member as that of Example 1 and the like. Are denoted by the same reference numerals and detailed description thereof will be omitted.

The present display device includes an organic EL display panel 900 which emits image light of first linearly polarized light, a reflection type polarization selection member 300, a transmission polarization axis variable section 400, and an absorption type polarization selection member 500. Composed. The organic EL display panel 900 transmits the first linearly polarized light component to the side facing the reflective polarization selection member 300 and absorbs the second linearly polarized light component whose polarization axis is orthogonal to this absorption type polarization selection member 208.
And the retardation plate 901 is arranged.

A quarter wavelength plate may be used as the retardation plate 901, and for example, a polymer film of uniaxially stretched polycarbonate, polysulfone, polyvinyl alcohol or the like can be used. Generally, due to the wavelength dependence of the refractive index of the material that constitutes the quarter-wave plate (hereinafter referred to as wavelength dispersion), one type of retardation plate produces a quarter wavelength over the entire visible wavelength range.
Although it is difficult to construct a retardation plate that functions as a wavelength plate, at least two types of retardation plates having different wavelength dispersions are bonded so that their optical axes are orthogonal to each other, and thus a quarter wavelength in a wide wavelength range. Anything configured to act as a plate can be used.

The organic EL display panel 900 is a self-luminous display device which converts electric energy into light energy by injecting a current into a light emitting layer made of an organic thin film to emit light, and a transparent substrate 902 made of ITO and transparent. An electrode 903, a hole transport layer 904, a light emitting layer 907, an electron transport layer 906, a reflective metal electrode 905 composed of Al or the like.
It has a structure in which layers are sequentially laminated. These laminated films are sealed with a sealant 908 in a state where oxygen and water are removed between the transparent substrate 902 and the sealing member 909 in order to suppress deterioration.

In the organic EL display panel, when a DC voltage is applied between the transparent electrode 903 which is an anode and the reflective metal electrode 905 which is a cathode, the holes injected from the transparent electrode 903 pass through the hole transport layer 904. In addition, the electrons injected from the cathode (reflective metal electrode) 905 reach the light emitting layer 907 via the electron transport layer, and the electrons
It is considered that holes are recombined to generate light of a predetermined wavelength. Since the light emitted from the light emitting layer 907 generally has no directivity and isotropically emitted in all directions,
In order to efficiently use the light directed to the metal electrode 905 as display light, it is desirable to use an electrode material having a high reflectance for the metal electrode.

The structure of the organic EL display panel 900 is as follows.
The configuration is not limited to the above. That is, the organic EL display panel according to the present invention can use a self-luminous display device including at least a light emitting layer and a reflective member disposed on the back surface of the light emitting layer.

Next, the operation of the display device of the ninth embodiment will be described with reference to FIG. The image display state is on the right side of FIG. 43,
The left side shows the mirror state.

When the display device is in the image display state, the transmission polarization axis varying section 400 is in a state in which no voltage is applied to the liquid crystal layer 407 constituting it, that is, in an off state. In the image display state, the light emitted from the light emitting layer is emitted from the transparent substrate 902 directly or after being reflected by the metal electrode 905 on the back surface.

Image light 320 emitted from the transparent substrate 902.
1 transmits through the retardation plate 901, and the absorption type polarization selecting member 20
When passing through 8, the first linearly polarized light component is transmitted and the second linearly polarized light component whose polarization axis is orthogonal to this is absorbed. The image light 3201 transmitted through the absorption type polarization selection member 208 also passes through the reflection type polarization selection member 300 and enters the transmission polarization axis variable unit 400. In this case, the transmission polarization axis varying unit 400
The image light 3201 that passes through is changed from the first linearly polarized light to the second linearly polarized light. The image light 3201 transmitted through the variable transmission polarization axis unit 400 is incident on the absorption type polarization selection member 500. The absorption-type polarization selection member 500 absorbs the first linearly polarized light component and transmits the second linearly polarized light component, so that the image light 3201 converted into the second linearly polarized light by the transmission polarization axis varying unit 400 is the absorption type. The light passes through the polarization selecting member 500 and is observed by the viewer 2000.

On the other hand, the external light 3202 incident on the display device from the observer 2000 side is unpolarized, but when transmitted through the absorption type polarization selection member 500, the first linearly polarized light component is absorbed and the second linearly polarized light component is absorbed. Only the linearly polarized light component is transmitted. The external light 3202 transmitted through the absorption polarization selection member 500 is changed from the second linear polarization light to the first linear polarization light when passing through the transmission polarization axis variable unit 400, and is transmitted through the reflection polarization selection member 300. And enters the organic EL display panel 900.

External light 3202 incident on the organic EL display panel 900 passes through the absorption type polarization selection member 208 and, when it passes through the retardation plate 901, is subjected to its action to be circularly polarized light (here, for example, clockwise rotation). Circularly polarized light). Phase plate 9
When the external light 3202 transmitted through 01 is reflected by the metal electrode 905, it becomes circularly polarized light (counterclockwise circularly polarized light) whose phase is shifted by π and the rotation direction is opposite. External light 320 reflected by the metal electrode 905
When the light beam 2 passes through the retardation plate 901 again, it receives the action and becomes the second linearly polarized light this time, which is the absorption type polarization selection member 20.
Since it is absorbed at 8, it does not return to the observer 2000 side.

Therefore, in the image display state, the image light 3201 emitted from the organic EL display panel 900 is directed to the observer with almost no loss, and a bright image can be obtained. In addition, external light 3 incident on the display device from the surroundings
In the case of the mirror state, 202 is not reflected by the reflection type polarization selection member 300 that functions as a mirror, and further, the light reflected by the metal electrode 905 of the organic EL display panel 900 is absorbed by the absorption type polarization selection member 208. However, it is hardly visible to the observer 2000. That is, it is possible to realize image display with a high contrast ratio in which unnecessary reflection of external light is suppressed.

On the other hand, when the display device is set to the mirror state, the transmission polarization axis varying section 400 applies an electric field to the liquid crystal layer 407 which constitutes the transmission polarization axis varying section 400 to turn it on. Observer 2 in the mirror state
The external light 3203 from the 000 side toward the display device is non-polarized light, but when transmitted through the absorption type polarization selection member 500,
Is absorbed, and only the second linearly polarized light component is transmitted and enters the transmission polarization axis variable unit 400. At this time, the external light 3203 that has entered the transmission polarization axis varying unit 400 passes through the transmission polarization axis varying unit 400 as the second linearly polarized light without changing the polarization axis, and reaches the reflection type polarization selection member 300. The reflective polarization selection member 300 transmits the first linearly polarized light component and specularly reflects the second linearly polarized light component.
The external light 3203 is reflected by the reflective polarization selection member 300.
The external light 3203 reflected by the reflection-type polarization selection member 300 is transmitted to the transmission polarization axis variable unit 400 without changing the polarization axis.
The linearly polarized light of (1) is transmitted as it is, and the polarization selecting member 500 is also transmitted to be directed to the observer, so that a mirror state is realized.

At this time, it is desirable that the display area of the organic EL display panel 900 corresponding to the area in the mirror state is in a non-light emitting state in conjunction with the operation of the mirror function.
By this operation, it is possible to completely eliminate the leakage of light from the back surface side of the reflective polarization selection member 300, so that it is possible to realize a high-quality mirror that projects a reflected image with a high contrast ratio, and further to increase the amount of emitted light. The power consumption of the display device is reduced by the amount that is suppressed.

However, the image light emitted from the organic EL display panel 900 is not always required to be in the non-light emitting state, and the image light emitted from the organic EL display panel 900 is absorbed. Since it is the first linearly polarized light that has passed through 208, the reflective polarization selecting member 30
0 is transmitted, and the first linearly polarized light is transmitted as it is through the transmission polarization axis varying unit 400 without changing the polarization axis, and is absorbed by the absorptive polarization selection member 500 and is hardly observed by the observer 2000. , It is possible to realize a mirror that projects a reflection image with a high contrast ratio.

The characteristics of the polarizing plates functioning as the absorption polarization selection member 208 and the absorption polarization selection member 500 are directly related to the image quality in the image display state and the visibility of the mirror in the mirror state.
Therefore, as in the first embodiment, in order to improve the brightness while maintaining a sufficient contrast ratio in the image display state, the absorption type polarization selection member 208 and the absorption type polarization selection member 50.
It is effective to use a polarizing plate having a high degree of polarization as one of the polarizing plates of 0 and a polarizing plate having a low degree of polarization as the other.

According to the display device of the present invention, as in each of the above-described embodiments, the reflection type polarization selection member functioning as a mirror is arbitrarily placed in the effectively transparent state and the state functioning as the mirror. Since they can be switched, there is an effect that the switching between the image display state and the mirror state can be realized without deteriorating the performance of each other. In other words, in the image display state, a bright image with almost no loss of image light is obtained, and even in a bright environment, there is no deterioration in image quality due to external light such as glare and a reduction in the contrast ratio, which is high quality. There is an effect that an image can be obtained.

On the other hand, in the mirror state, a bright mirror can be realized because it efficiently reflects outside light, and further, leakage of image light is suppressed, so that a mirror that projects a reflected image with a high contrast ratio can be realized. There is. Therefore, in the mirror state, an easily visible reflection image suitable for a person to see and observe his / her face or figure is obtained.

[0318]

As described above, according to the present invention,
It is possible to provide a device that can be switched between a state in which a high-quality image is displayed and a mirror state in which a reflection image that is easy to see and is suitable for a person to observe by observing his / her face or figure can be obtained.

[Brief description of drawings]

FIG. 1 is an explanatory diagram for explaining a basic configuration and an operation of a display device with a function for switching to a mirror state according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram for explaining the basic configuration and operation of the display device with a function for switching to a mirror state according to the first embodiment of the present invention.

FIG. 3 is a graph showing light leakage in a bright display area when the display device of FIGS. 1 and 2 is in a mirror state.

FIG. 4 is a graph showing light leakage in a dark display region when the display device of FIGS. 1 and 2 is in a mirror state.

FIG. 5 is an explanatory diagram for explaining the basic configuration and operation of the display device with a function for switching to a mirror state according to the second embodiment of the present invention.

FIG. 6 is an explanatory diagram for explaining a basic configuration and an operation of a display device with a function for switching to a mirror state according to a second embodiment of the present invention.

FIG. 7 is a cross-sectional view showing the configuration of the display device according to the first embodiment of the present invention.

FIG. 8 is a cross-sectional view of each member constituting the display device according to the first embodiment of the present invention.

FIG. 9 is an explanatory diagram of an axial direction of each member that constitutes the display device according to the first exemplary embodiment of the present invention.

FIG. 10 is an explanatory diagram for explaining the operation of the display device according to the first embodiment of the present invention.

FIG. 11 is an explanatory diagram for explaining the operation of the display device according to the first embodiment of the present invention.

FIG. 12 is a graph showing an example of the relationship between the degree of polarization and the transmittance of a general polarizing plate.

FIG. 13 is a graph showing the relationship between the polarization degree of the absorptive polarization selection member 500 according to the display device of Example 1 of the present invention and the reflectance in the mirror state and the reflectance of external light in the image display state. is there.

FIG. 14 is a graph showing the relationship between the degree of polarization of the absorptive polarization selection member 208 according to the display device of Example 1 of the present invention and the display brightness in an image display state.

FIG. 15 is a cross-sectional view showing a configuration of a display device according to a second embodiment of the present invention.

FIG. 16 is a cross-sectional view of each member constituting the display device according to the second embodiment of the present invention.

FIG. 17 is a cross-sectional view showing an example of the configuration of a variable polarization selection member 600 of the display device according to the second embodiment of the present invention.

FIG. 18 is a cross-sectional view showing an example of the configuration of a variable polarization selecting member 600 of the display device according to the second embodiment of the present invention.

FIG. 19 is an explanatory diagram of an axial direction of each member that constitutes the display device according to the second exemplary embodiment of the present invention.

FIG. 20 is an explanatory diagram showing the operation of the display device according to the second embodiment of the present invention.

FIG. 21 is an explanatory diagram showing the operation of the display device according to the second embodiment of the present invention.

FIG. 22 is an explanatory diagram showing a schematic configuration of a display device according to a third embodiment of the present invention.

FIG. 23 is a partial cross-sectional view of a transmissive screen of the display device according to the third embodiment of the present invention.

FIG. 24 is a partial cross-sectional view showing an example of a lenticular lens sheet of a display device of Example 3 of the present invention.

FIG. 25 is a partial perspective view showing an example of a lenticular lens sheet of a display device according to Example 3 of the present invention.

FIG. 26 is a partial cross-sectional view of a transmissive screen according to the display device of Example 3 of the present invention.

FIG. 27 is a cross-sectional view of each member constituting the display device according to the fourth embodiment of the present invention.

FIG. 28 is an explanatory diagram of an axial direction of each member which constitutes the display device according to the fourth exemplary embodiment of the present invention.

FIG. 29 is a cross-sectional view of each member constituting the display device according to the fifth embodiment of the present invention.

FIG. 30 is an explanatory diagram of an axial direction of each member that constitutes the display device according to the fifth exemplary embodiment of the present invention.

FIG. 31 is an explanatory diagram illustrating an operation of the display device according to the fifth embodiment of the present invention.

FIG. 32 is a cross-sectional view of each member constituting the display device according to the sixth embodiment of the present invention.

FIG. 33 is an explanatory diagram of an axial direction of each member that constitutes the display device according to the sixth embodiment of the present invention.

FIG. 34 is an explanatory diagram for explaining the operation of the display device according to the sixth embodiment of the present invention.

FIG. 35 is an explanatory diagram for explaining the operation of the display device according to the sixth embodiment of the present invention.

FIG. 36 is a schematic configuration diagram for explaining the operation of the display device of the present invention.

FIG. 37 is a partial cross-sectional view of the display device according to the seventh embodiment of the present invention.

38 (a) and 38 (b) are top views showing an overview of a mobile phone according to a seventh embodiment of the present invention.

FIG. 39 is a block diagram showing a schematic functional configuration of a mobile phone according to a seventh embodiment of the present invention.

FIG. 40 is a top view showing an overview of a mobile phone according to an eighth embodiment of the present invention.

FIG. 41 is a partial cross-sectional view showing an example of a detachable mirror function part according to Example 8 of the invention.

FIG. 42 is a block diagram showing a schematic functional configuration of a drive unit of a mirror function section according to the eighth embodiment of the present invention.

FIG. 43 is a partial cross-sectional view showing an example of the display device of Example 9 of the present invention.

FIG. 44 is a graph showing light leakage in a shutter state of a conventional display device.

[Explanation of symbols]

100 ... Lighting device, 200 ... Liquid crystal display panel, 208 ...
Absorption-type polarization selection member, 300 ... Reflection-type polarization selection member, 3
01 ... Reflective polarization selection member, 400 ... Transmission polarization axis variable section, 500 ... Absorption polarization selection member, 600 ... Variable polarization selection member, 701 ... Projection device, 702 ... Mirror, 703 ...
Transmissive screen.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-11-223680 (JP, A) JP-A-63-245801 (JP, A) JP-A-7-333574 (JP, A) JP-A-11- 84370 (JP, A) JP 11-84034 (JP, A) JP 11-194359 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G02F 1/1335

Claims (17)

(57) [Claims] 1. An image display unit that emits image light for displaying a desired image, and an image transmission state that transmits the image light and reflects external light, which is arranged so as to be superimposed on the image display unit. A mirror function unit that can be switched to a mirror state, and the mirror function unit is arranged in order from the image display unit side,
A reflection type polarization selecting unit, a transmission polarization axis changing unit, and an absorption type polarization selecting unit are included, and the reflection type polarization selecting unit transmits the first polarized light having a predetermined polarization axis and transmits the first polarized light. And a second polarized light having a polarization axis intersecting with each other is reflected, and the transmission polarization axis changing means changes the incident first polarized light to the second polarized light and transmits the second polarized light, and a polarization axis of the incident light. It is possible to switch to a transparent state without changing
The absorptive polarized light selecting unit transmits one of the first polarized light and the second polarized light and absorbs the other, and the image display unit transmits the first polarized light and the second polarized light.
Image-light polarization selecting means that absorbs the polarized light of, and emits the first polarized light that has passed through the image-light polarization selecting means as the image light. Possible device. 2. The apparatus according to claim 1, further comprising switching means for switching the mirror function section between the image transmission state and the mirror state, the switching means comprising the transmission polarization axis varying means. By switching the first polarized light to the second polarized light, the mirror function unit is switched to the image transmission state, and the transmission polarization axis varying means transmits the incident polarization axis without changing the incident polarization axis. An apparatus capable of switching between an image display state and a mirror state, wherein the mirror function unit is switched to the mirror state by switching to the state. 3. The apparatus according to claim 1, further comprising switching means for switching the mirror function section between the image transmission state and the mirror state, and the switching means includes the transmission polarization axis varying means. By switching the incident polarization axis to a transmission state without changing, the mirror function section is switched to the image transmission state, and the transmission polarization axis changing means changes the first polarization to the second polarization. An apparatus capable of switching between an image display state and a mirror state, wherein the mirror function unit is switched to the mirror state by switching to the state. 4. An image display section that emits image light for displaying a desired image, an image transmission state that transmits the image light and reflects external light, which is arranged so as to be superimposed on the image display section. A mirror function unit that can be switched to a mirror state, and the mirror function unit is arranged in order from the image display unit side,
First reflection type polarization selection means, transmission polarization axis varying means,
A second reflection type polarization selecting unit and a variable polarization selecting unit are included, and the first reflection type polarization selecting unit transmits the first polarization having a predetermined polarization axis, and transmits the first polarization and the polarization. The second polarization changing means reflects the second polarized light whose axes intersect, and changes the polarization axis of the incident light by changing the incident first polarized light into the second polarized light and transmitting the second polarized light. It is possible to switch to a state in which the light is transmitted without being caused to occur, and the second reflection type polarization selection means is configured to transmit the first polarized light and the second polarized light.
One of the polarized lights of the first polarized light is reflected and the other is transmitted, and the variable polarization selecting means absorbs one of the first polarized light and the second polarized light and transmits the other polarized light. The image display unit transmits the first polarized light and the second
Image-light polarization selecting means that absorbs the polarized light of, and emits the first polarized light that has passed through the image-light polarization selecting means as the image light. Possible device. 5. The apparatus according to claim 4, further comprising switching means for switching the mirror function section between the image transmission state and the mirror state, and the switching means includes the transmission polarization axis varying means. By switching the first polarized light to the second polarized light and switching the variable polarization selection means to the state of absorbing the first polarized light and transmitting the second polarized light, The mirror function unit is switched to the image transmission state, the transmission polarization axis varying unit is switched to the transmission state without changing the incident polarization axis, and the variable polarization selecting unit is configured to transmit all the polarization components. An apparatus capable of switching between an image display state and a mirror state, wherein the mirror function unit is switched to the mirror state by switching to. 6. The apparatus according to claim 4, further comprising switching means for switching the mirror function section between the image transmission state and the mirror state, and the switching means includes the transmission polarization axis changing means. The mirror function unit is configured by switching the incident polarization axis to a transmission state without changing the polarization axis and switching the variable polarization selection means to a state of absorbing the second polarization and transmitting the first polarization. To the image transmission state, the transmission polarization axis changing means is changed to a state in which the first polarization is changed to the second polarization, and the variable polarization selecting means transmits all the polarization components. An apparatus capable of switching between an image display state and a mirror state, wherein the mirror function unit is switched to the mirror state by switching to. 7. An image display section for emitting image light for displaying a desired image, an image transmission state for transmitting the image light and external light, which are arranged so as to be superimposed on the image display section. A mirror function unit that can be switched to a mirror state, and the mirror function unit is arranged in order from the image display unit side,
First reflection type polarization selection means, transmission polarization axis varying means,
A second reflection-type polarization selection means, wherein the first reflection-type polarization selection means transmits a first polarization having a predetermined polarization axis, and a second polarization crossing the first polarization and the polarization axis. Of the polarized light, and the transmission polarization axis varying means changes the incident first polarized light to the second polarized light and transmits the polarized light, and transmits the incident light without changing the polarization axis of the incident light. And the second reflection type polarization selection means is
One of the first polarized light and the second polarized light is reflected and the other is transmitted, and the image display unit transmits the first polarized light and the second polarized light is transmitted.
Image-light polarization selecting means that absorbs the polarized light of, and emits the first polarized light that has passed through the image-light polarization selecting means as the image light. Possible device. 8. The apparatus according to claim 2, 3, 5 or 6, wherein the image display unit is switchable to a state in which the image light is not emitted, and the switching unit switches the mirror function unit to the mirror function unit. A device capable of switching between an image display state and a mirror state in which the image display unit is switched to a state in which the image light is not emitted when the state is switched to the state. 9. The apparatus according to claim 8, wherein the image display unit includes a lighting device and a liquid crystal element, and the switching unit switches the image display unit to a state in which the image light is not emitted. To turn off the lighting device,
Alternatively, a device capable of switching between an image display state and a mirror state, which is characterized in that the liquid crystal element is switched to dark display. 10. The apparatus according to claim 8, wherein the transmission polarization axis changing means is configured to be able to switch only a part of the area to a state of transmitting the light without changing the incident polarization axis. The means switches the display of the image display unit in a portion overlapping with the partial region to a dark display when switching only the partial region to a state of transmitting the incident light without changing the incident polarization axis. And a device capable of switching between an image display state and a mirror state, wherein the image light is not emitted from the portion. 11. The device according to claim 1, 4 or 7, wherein the transmission polarization axis varying means includes a liquid crystal layer and an electrode for applying an electric field in a layer thickness direction of the liquid crystal layer. In the liquid crystal layer, when the electric field is not applied, the long axis direction of the liquid crystal molecules is continuously twisted by 90 degrees in the layer thickness direction, and when the electric field is applied, the long axis direction of the liquid crystal molecules is in the layer thickness direction. When the mirror function section is in a mirror state, the transmission polarization axis varying means is in a state in which an electric field is applied to the liquid crystal layer. Switchable device. 12. The device according to claim 1, 4 or 7, wherein the transmission polarization axis varying means includes a liquid crystal layer and an electrode for applying an electric field in a layer thickness direction of the liquid crystal layer. In the liquid crystal layer, when the electric field is not applied, the long axis direction of the liquid crystal molecules is continuously twisted by 90 degrees in the layer thickness direction, and when the electric field is applied, the long axis direction of the liquid crystal molecules is in the layer thickness direction. When the mirror function section is in a mirror state, the transmission polarization axis varying means is in a state in which an electric field is not applied to the liquid crystal layer. Switchable device. 13. The apparatus according to claim 1, wherein, when the polarization degree of the image light polarization selection means is P1 and the polarization degree of the absorption type polarization selection means is P2, 0.966 ≦ P1 ≦
An apparatus capable of switching between an image display state and a mirror state, characterized by satisfying a relation of 0.995 ≦ P2. 14. The apparatus according to claim 1, wherein, when the polarization degree of the image light polarization selecting means is P1 and the polarization degree of the absorption type polarization selecting means is P2, 0.966 ≦ P2 ≦
When the relationship of 0.995 ≦ P1 is satisfied and the mirror function unit is switched to the mirror state, the image display unit is switched to a state in which the image light is not emitted in conjunction with this. A device that can switch between an image display state and a mirror state. 15. The apparatus according to claim 4 or 7, wherein the first reflection type polarization selecting means is arranged such that a distance between the first reflection type polarization selecting means and the second reflection type polarization selecting means is 0.11 mm or less. A device capable of switching between an image display state and a mirror state. 16. The image display according to claim 1, 4 or 7, wherein the mirror function section has a size of a region in a mirror state of at least 58.6 mm × 39.1 mm. A device that can switch between the state and the mirror state. 17. The apparatus according to claim 1, wherein the image display section includes an organic electroluminescence display element, and a position is provided between the light emitting layer of the organic electroluminescence display element and the reflection type polarization selection means. An apparatus capable of switching between an image display state and a mirror state, wherein a phase difference plate and the image light polarization selection means are arranged.