JPH1164819A - Display element, display device and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To display in transmission type only a part emitted with a light source, to display irreducible minimum information in a dark place and to reduce light quantity, power in the light source by providing a polarized light separating means emitting linear polarization in the prescribed direction. SOLUTION: Although light emitted from the light source transmits through a 1/4 wavelength plate 106, since the light emitted from the light source 104 is non- polarized light, it transmits through as it is to become linear polarization parallel to a paper surface by a polarized light separator 103. Further, the polarization direction of the light is twisted by nearly 90 deg. by a liquid crystal layer 102c to become linear polarization perpendicular to the paper surface. Then, since the light is the linear polarization perpendicular to the paper surface, it can't transmit through the polarized light separator 101 to become a black display. Further, though the light emitted from the light source 104 transmits through the 1/4 wavelength plate, since the light emitted from the light source 104 is the non-polarized light, it transmits through as it is to become the linear polarization parallel to the paper surface by the polarized light separator 103. Further, the polarization, direction is hardly twisted by the liquid crystal layer 102d to become the linear polarization parallel to the paper surface. Then, since the light is the linear polarization parallel to the paper surface, it transmits through the polarized light separator 101 to become a white display.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal device, and more particularly, to a liquid crystal display device and an electronic apparatus using the same.

[0002]

2. Description of the Related Art Conventional TN (Twisted Nematic) liquid crystal and S
In a display device using a transmission polarization axis variable optical element such as a TN (Super-Twisted Nematic) liquid crystal whose polarization axis is variable, a structure in which this transmission polarization axis variable optical element is sandwiched between two polarizing plates is adopted. Therefore, light utilization efficiency is poor, especially placing a reflector such as aluminum on one outside of this polarizing plate,
A reflective display element causes a dark display, which is a problem.

[0003] Among the light transmitted through a polarizing plate having a reflector (hereinafter referred to as a back surface and the opposite side is referred to as a front surface), light having a transmission axis direction component of the polarizing plate is included. Light is absorbed at the time of transmission, and the reflectance is 10
The light is reflected by a reflection plate made of aluminum or the like which is not 0%, and becomes dark because light is absorbed by the polarizing plate again.

In addition, a semi-transmissive reflection plate which transmits light to some extent and reflects light to some extent is used in place of a reflector made of aluminum or the like, and a transflective display element structure in which a light source is provided on the back of the reflector has a semi-transmissive type. The reflectance of the reflector becomes worse,
When viewed as a reflective liquid crystal display device using external light from the front with the light source turned off, the display becomes even darker. When viewed as a transmissive display element with the light source attached, since the light from the light source is absorbed by the transflective plate, the display is also dark, which is hardly practical.

In order to solve this problem, of the incident light, only light having a polarization component in a predetermined direction is transmitted as linearly polarized light instead of the rear polarizing plate and the reflecting plate or the semi-transmissive reflecting plate. There is a method using a polarization separator that reflects light of a polarization component in a direction orthogonal to the direction. Examples of such a polarization separator include a polarization separator combining a (1/4) wavelength plate and a cholesteric liquid crystal layer, and an internationally published international application (international application numbers: WO95 / 27819 and WO95 / 17).
692).

The use of such a light separator eliminates unnecessary light absorbing members, and provides a bright display. Further, since a transflective plate is not required, the brightness of the light source is not attenuated, and the display becomes bright even when displayed as a transmissive display element.

Therefore, it has become possible to display both the reflective display and the transmissive display brightly.

[0008]

However, even in such a configuration, in the case of transmission type display, the entire surface of the variable transmission polarization axis optical element is always irradiated with light, so that the power of the light source is unnecessary. It was getting bigger.

The present invention has been made in view of such a problem.

That is, an object of the present invention is to make it possible to display as a reflective display element under bright external light, and to make it possible to display only a minimum necessary information display portion in a dark place in a transmissive type, thereby reducing the power of the light source. We are trying to reduce it.

[0011]

According to a first aspect of the present invention, there is provided a display element according to the present invention, wherein a transmission polarization axis variable means having a variable transmission axis and a first polarization disposed on one side of the transmission polarization axis variable means. A second polarization separation means disposed on the other side of the separation means and the transmission polarization axis variable means, and a first polarization separation means disposed on the opposite side of the transmission polarization axis variable means with respect to the second polarization separation means.
And a second optical element, wherein the first polarized light separating means receives light incident on the transmission polarization axis variable means from the side opposite to the second polarized light separating means. The linearly polarized light component of the first predetermined direction is transmitted as linearly polarized light to the transmission polarization axis variable means side, and light incident on the transmission polarization axis variable means from the side opposite to the second polarization separation means. The linearly polarized light component in a second predetermined direction orthogonal to the first predetermined direction is not transmitted to the transmission polarization axis variable means side, and the second polarization separation is performed on the transmission polarization axis variable means. The linearly polarized light component in the first predetermined direction out of the light incident from the means side is transmitted as linearly polarized light to the opposite side to the second polarized light separating means, and the second polarized light is transmitted to the transmitted polarization axis changing means. Of the light incident from the polarization separation means side A polarization splitting unit that does not transmit a second predetermined linearly polarized light component to the opposite side to the second polarization splitting unit, wherein the second polarization splitting unit is configured to detect light incident from the transmission polarization axis changing unit side. The linearly polarized light component in the third predetermined direction is transmitted to the first optical element and the second optical element side, and the linearly polarized light component in the fourth predetermined direction orthogonal to the third predetermined direction. The component is reflected to the transmission polarization axis changing unit side, does not transmit the polarization component in the fourth predetermined direction in the light incident from the first optical element side, and the first optical element and the second A polarization splitting unit capable of emitting linearly polarized light in the third predetermined direction to the transmission polarization axis changing unit with respect to light incident from the second optical element side, wherein the first optical element is the first optical element; A light source, wherein the second optical element is a light absorbing member. To.

With this configuration, it is possible to perform the transmissive display only on the portion illuminated by the first light source.
Necessary minimum information can be displayed, and the amount of light and power of the first light source to be displayed can be reduced.

According to a second aspect of the present invention, in the display device of the first aspect, the second optical element is a second light source.

In this way, by turning on the first light source and the second light source as needed, a lot of information can be displayed in a dark place.

According to a third aspect of the present invention, in the display device, the second optical element is a photoelectric conversion element.

In this way, under bright external light, a part of the external light can be converted to electric power by the photoelectric conversion element, and the power consumption can be reduced by using the external light for driving the display element, for example.

According to a fourth aspect of the present invention, in the display device of the present invention, the transmission polarization axis variable means, the first polarization separation means, the second polarization separation means, and the second polarization separation means are transmitted through the transmission element. A display device comprising: a third optical element disposed on the opposite side to the polarization axis changing means; and a third light source disposed between the second polarization separation means and the third optical element. The third optical element is characterized in that the third optical element is a light absorbing member.

With this configuration, it is possible to perform the transmissive display only on the portion irradiated by the third light source,
Necessary minimum information can be displayed, and the amount of light and power of the first light source to be displayed can be reduced. Further, in the case of the reflection type display, a display which is easy to see without a seam in the display can be provided.

According to a fifth aspect of the present invention, in the display device of the fourth aspect, the third optical element is a fourth light source.

In this way, by turning on the fourth light source as needed, it is possible to display a lot of information in a dark place. Also, at this time, a display that is easy to see without a seam in the display can be provided.

According to a sixth aspect of the present invention, there is provided the display element according to the fourth aspect, wherein the third optical element is a photoelectric conversion element.

In this way, the area of the photoelectric conversion element can be increased, and a part of the external light can be converted into more power. For example, the power consumption can be further reduced by using the driving power for the display element. .

According to a seventh aspect of the present invention, in the display device of the first to sixth aspects, the transmission polarization axis changing means is a liquid crystal element.

In this way, it is possible to obtain an inexpensive hyperpolarization axis changing means which is easy to control.

According to the display element of the present invention described in claim 8, in the display element of claim 7, the transmission polarization axis varying means is a TN liquid crystal element, an STN liquid crystal element, or an F-STN liquid crystal element.
It is a liquid crystal element or an ECB liquid crystal element.

In this way, more favorable response speed and contrast can be obtained.

According to a ninth aspect of the present invention, in the display element of the first to eighth aspects, the first polarization separating means is a polarizing plate.

[0028] With this configuration, the first manufacturing method, which is easy to manufacture, can be used.
Is obtained.

According to a tenth aspect of the present invention, there is provided a display device including the display element according to the first to ninth aspects, wherein at least the two modes of a mode for displaying a part of the display element and a mode for displaying the entire surface. Is provided.

In this manner, the minimum necessary information can be displayed in a transmissive display in a dark place, and a large amount of information can be displayed as necessary. The power required to control the polarization axis varying means can be reduced.

According to an eleventh aspect of the present invention, there is provided an electronic apparatus comprising the display device according to the tenth aspect, and switching means for switching between the two modes of the display device.

With this configuration, it is possible for the user to display the minimum necessary information and a large amount of information by the switching means, and unnecessary power can be suppressed. In particular, battery-operated electronic devices can extend battery life.

An electronic device according to a twelfth aspect of the present invention is the electronic device according to the eleventh aspect, wherein at least a part of the switching means is disposed in the display device.

With this arrangement, the operability of the switching means is improved, and the appearance of the electronic device is improved.

[0035]

Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 FIG. 1 is a diagram showing a schematic cross section and an optical path of a display device of this embodiment.

In the figure, reference numeral 100 surrounded by a broken line is a display element of this embodiment.

Reference numeral 101 denotes a polarization separator, and in this embodiment, a polarizing plate is used as a preferred example because of its ease of production. Note that the polarization separator 101 may be a polarizing plate in which, for example, a color film or an anti-glare film is laminated.

The polarization separator 101 does not transmit linearly polarized light in a direction perpendicular to the plane of the paper, but transmits linearly polarized light in a direction parallel to the paper, and is arranged in such a manner.

Reference numeral 102 enclosed by a broken line denotes a variable transmission polarization axis optical element. In this embodiment, a TN liquid crystal element is used. Here, the variable transmission polarization axis optical element 102 includes a pair of substrates 1.
02a and 102b sandwich the liquid crystal layers 102c and 102d. The liquid crystal layer 102c shows a state where no voltage is applied thereto, twists the direction of the incident linearly polarized light by about 90 ° and emits it, and the liquid crystal layer 102d shows a state where a voltage is applied thereto. The emitted linearly polarized light is emitted with almost no twist.

Reference numeral 103 denotes a polarization separator, which in this embodiment is an internationally published international application (international application number: WO95 / 2).
7819 and WO95 / 17692). This polarized light separator 102 has a function of (1 /
4) A film in which a wave plate and a cholesteric liquid crystal layer are combined, and a multilayer film is laminated (USP 4,974,21).
9) Separation into reflected polarized light and transmitted polarized light by using the angle of Brewster (SID92 DIGEST No. 4
27 to 429), and a hologram may be used. In this case, the polarization separator 103 reflects linearly polarized light in a direction perpendicular to the paper surface and transmits linearly polarized light in a parallel direction, and is arranged as such.

Reference numeral 104 denotes a light source. In this embodiment, an EL (electroluminescence) is used. However, an LED (light-emitting diode), an incandescent lamp, a cold cathode tube, a hot cathode tube, or a light source for uniformizing these lights. A combination of the above members may be used as the light source.

Reference numeral 105 denotes a light absorbing layer, which is formed of a plate or a film having a low reflectance.

Here, the color and reflectance of the light source 104 and the light absorbing layer 105 that do not emit light are preferably the same as much as possible.

Reference numeral 106 denotes a (1/4) wavelength plate,
4) The angle between the slow axis of the wave plate and the direction of the linearly polarized light transmitted by the polarization separator 103 is about 45 °.

The (1/4) wavelength plate 106 is not directly related to the present invention, and may be omitted, or may be replaced with a diffusion plate for diffusing light.

The configuration is as described above.

The display element 100 has the above configuration.

The display elements 107 to 110 correspond to the display elements 10.
4 shows an optical path when the light source 104 of 0 is not turned on.

Reference numeral 107 denotes an optical path of external light (light from above in the figure) in the liquid crystal layer 102c (portion to which no voltage is applied) corresponding to a position of the light absorbing layer 105. The optical path of external light in the layer 102d (portion to which a voltage is applied) is shown.

Reference numeral 109 denotes an optical path of external light in the liquid crystal layer 102c corresponding to a position of the light source 104, and reference numeral 110 denotes
The optical path of external light in the liquid crystal layer 102d is shown.

Symbols with arrows on the left and right on the optical path indicate linearly polarized light parallel to the plane of the paper, and symbols with x superimposed thereon indicate linearly polarized light perpendicular to the plane of the paper.

Here, the optical paths 107 and 109 will be described first.

The external light is converted by the polarization separator 101 into linearly polarized light parallel to the paper surface.

Then, the polarization direction is twisted by about 90 ° by the liquid crystal layer 102c, and becomes a linearly polarized light perpendicular to the paper surface.

Then, since the light is linearly polarized light perpendicular to the paper surface, it is reflected by the polarization splitter 103.

The reflected light is again twisted by about 90 ° by the liquid crystal layer 102c to become linearly polarized light parallel to the plane of the drawing.

Then, since the light is linearly polarized light parallel to the plane of the paper, it passes through the polarization separator 101.

As described above, since the external light is reflected and returned, it becomes bright. That is, white display is performed.

Next, the optical paths 108 and 110 will be described.

The external light is converted by the polarization separator 101 into linearly polarized light parallel to the plane of the drawing.

Then, the direction of polarization is hardly twisted by the liquid crystal layer 102d, and remains linearly polarized light parallel to the plane of the drawing.

Then, since the light is linearly polarized light parallel to the paper surface, it passes through the polarization separator 103.

Then, the light passes through the (1/4) wavelength plate 106,
For the optical path 108, this light is absorbed by the light absorbing layer 105, and for the optical path 110,
Absorbed in 4.

As described above, the external light does not return and darkens. That is, black display is performed.

Here, the linearly polarized light that has passed through the polarization separator 103 and is parallel to the paper surface is converted into circularly polarized light by the ()) wavelength plate 106, and is converted into the light absorbing layer 105 or the light source 1 that does not emit light.
Reach 04.

Then, at least a part of the circularly polarized light is reflected without being absorbed, re-enters the (４) wavelength plate 106, and exits to the polarization separator 103 side. At this time, the circularly polarized light is changed to a linearly polarized light. However, the linearly polarized light is in a direction perpendicular to the paper surface and cannot pass through the polarization separator 103.

As described above, by providing the (1/4) wavelength plate 106, even when the reflectance of the light absorbing layer 105 or the light source 104 that does not emit light is not so small, darker black display can be performed.

Next, the light source 1 of the display element 100 is placed in a dark place.
A case in which No. 04 is turned on will be described.

FIG. 2 is a diagram showing a schematic cross section and an optical path of the display element 100.

In FIG. 2, the structure of the display element 100 is the same, and the same number is assigned and the description is omitted.

Reference numerals 111 and 112 denote optical paths of light emitted from the light source 104. 111 indicates an optical path in the liquid crystal layer 102c, and 112 indicates an optical path in the liquid crystal layer 102d.

Since light does not reach the portion located on the absorption layer 105, no display is visible.

First, the optical path 111 will be described.

The light emitted from the light source 104 passes through the (1/4) wavelength plate 106, but the light emitted from the light source 104 is unpolarized and passes through as it is.

Then, the polarized light is converted into linearly polarized light parallel to the paper by the polarization separator 103.

Then, the polarization direction is twisted by about 90 ° by the liquid crystal layer 102c, and becomes a linearly polarized light perpendicular to the paper surface.

Then, since the light is linearly polarized light perpendicular to the plane of the paper, the light cannot pass through the polarization separator 101.

Accordingly, black display is performed.

Next, the optical path 112 will be described.

The light emitted from the light source 104 passes through the (1/4) wavelength plate, but the light emitted from the light source 104 passes through as it is because it is unpolarized.

Then, the polarized light is converted into linearly polarized light parallel to the paper by the polarization separator 103.

Then, the polarization direction is almost twisted by the liquid crystal layer 102d, and becomes a linearly polarized light parallel to the paper surface.

Then, since the light is linearly polarized light parallel to the plane of the paper, it passes through the polarization separator 101.

Accordingly, white display is obtained.

Therefore, it is possible to perform display as a transmissive display element in the light source 104 portion.

The operation is as described above.

Therefore, under bright external light, reflective display is performed partially or entirely, and in dark places, the light source 104 is turned on, and transmissive display is performed at a portion corresponding to this portion.

Here, since the light source 104 only needs to be able to illuminate the area of a part of the display, the light amount of the light source, and consequently the power consumption can be reduced. Further, the size of the light source can be reduced.

In the present embodiment, the absorption layer 105 and the light source 104 are provided one by one, and the display section is divided into two parts.
Of course, these absorbing layers and light sources may be added. In other words, there can be two or more transmissive displayable portions.

[Embodiment 2] The absorbing layer 105 of Embodiment 1
It can be replaced by another optical element.

FIG. 3 is a schematic sectional view of the display element of this embodiment.

In the figure, the configuration other than 300 and 301 is shown in FIG.
The same reference numerals are used to denote the same, and the description is omitted.

Reference numeral 300 enclosed by a broken line denotes a display device of the present embodiment, and reference numeral 301 denotes a light source, which is replaced with the absorption layer 105 of FIG.

With the above configuration, it is possible to perform reflective display over the entire surface under bright external light as in the first embodiment.

In a dark place, the light source 104 is turned on, and a transmissive display is performed on a portion corresponding to the portion, and the light source 301 is turned on, and a transmissive display is performed on a portion corresponding to the portion. , The light source 104 and the light source 301 are turned on at the same time, so that a transmissive display can be performed on the entire surface.

Therefore, not only can the light source 104 be turned on in a dark place to display the necessary minimum information, but also the light source 301 can be turned on only when necessary to display a lot of information. It is possible. Therefore, it is possible to prevent the power of the light source from being wastefully consumed.

[Embodiment 3] Further, the absorbing layer 105 of the embodiment 1
Can be replaced by a photoelectric conversion element.

Here, the photoelectric conversion element is a so-called solar cell or the like that absorbs light and converts it into electric energy.

In this configuration, since the photoelectric conversion element also functions as an absorption layer, it operates in the same manner as in the first embodiment, obtains the same effect, and can reduce the light absorbed by the photoelectric conversion element under bright external light. Since the electric energy is converted into electric energy, for example, the electric energy can be used for driving the display element. Therefore, the power consumption of the display device including the display element is reduced.

[Embodiment 4] In Embodiment 1, the light source 104 and the absorbing layer 105 are arranged side by side. With such an arrangement, the boundary of the adjacent portion appears as a seam in the reflective display. You may be worried about this.

In order to prevent this, a light source may be provided between the polarization separator 103 and the absorption layer 105.

FIG. 4 is a schematic sectional view of the display device of this embodiment.

In the figure, except for 400, 401 and 402, FIG.
The same reference numerals are used to denote the same parts, and description thereof is omitted.

In the figure, reference numeral 400 denotes a display device according to the present embodiment.

Reference numeral 401 denotes a light source, which uses an incandescent light bulb, but other types of light sources may of course be used. The light intensity of the light source 401 may be weak enough to irradiate a part of the variable transmission polarization axis element 102.

Numeral 402 denotes an absorption material, and a transmission polarization axis varying means 1
02 is arranged corresponding to the entirety of the image.

Here, the light source 401 and the absorbing material 402 may have different colors and reflectivities.

With the above structure, no joint is visible even when the reflective display is performed under bright external light, and in a dark place, by turning on the light source 401, a part of the transmission polarization axis variable Since light is emitted from the back surface, transmissive display can be performed as in the first embodiment.

Accordingly, the same effect as that of the first embodiment can be obtained, and a seamless display can be obtained.

[Embodiment 5] In Embodiment 2, the light source 10
Although the light source 4 and the light source 301 are arranged side by side, in such an arrangement, the boundary of the adjacent portion may be seen as a seam when performing transmissive display, and this may be annoying.

To prevent this, a light source may be provided between the polarization splitter 103 and the light source 301.

FIG. 5 is a schematic sectional view of the display element of this embodiment.

In the figure, except for 500, 501 and 502, FIG.
The same reference numerals are used to denote the same parts, and description thereof is omitted.

In the figure, reference numeral 500 enclosed by a broken line denotes a display device of this embodiment.

Reference numeral 501 denotes a light source, which uses EL here, but of course other types of light sources may be used.

The light source 501 is arranged corresponding to the entire transmission polarization axis changing means 102.

Reference numeral 502 denotes another light source, in which an incandescent light bulb is used. However, another light source may be used.

The configuration is as described above. Therefore, under bright external light, it is possible to perform reflective display on a part or the entire surface as in the second embodiment. In dark places, light source 5
By turning on 02, it becomes possible to perform transmissive display on a part, and by turning off the light source 502 and turning on the light source 501, transmissive display can be performed on the entire surface.
The same effect as described above can be obtained, and a seamless display can be obtained.

[Embodiment 6] By replacing the light absorbing material 402 of Embodiment 4 with a photoelectric conversion element, the same effect as that of Embodiment 3 can be obtained, a seamless display can be obtained, and the area of the photoelectric conversion element can be further improved. And the amount of electric energy that can be generated increases, and the power consumption of a display device including this display element can be further reduced.

The display elements of the present invention have been described in Examples 1 to 6.

In the first to sixth embodiments, only the black display and the white display have been described. Of course it can be applied.

Further, as a transmission polarization axis variable optical element, T
Although the description has been made using the N liquid crystal element, the present invention is not limited to this, and an STN liquid crystal element, an ECB liquid crystal element, or the like can be used. In particular, an STN liquid crystal element can easily obtain a high contrast, and an STN liquid crystal element using an optically anisotropic body for color compensation such as an F-STN liquid crystal element is preferably used. As the variable transmission polarization axis optical element, an inexpensive liquid crystal element that is easy to control is suitable, but is not limited thereto.
If necessary, for example, a ferroelectric porcelain PLZT or the like may be used.

[Embodiment 7] The present embodiment relates to a display device of the present invention.

By using the display element described in Embodiments 1 to 6 as a display member, a bright display device can be provided, and necessary information can be displayed in a dark place in a transmissive manner. .

FIG. 6 is a block diagram of the display device of this embodiment.

In FIG. 6, reference numeral 600 denotes a display device according to the present embodiment.

Reference numeral 100 denotes a display element 100 described with reference to FIG. 1 of the first embodiment, reference numeral 104 denotes a light source, and reference numeral 105 denotes a light absorbing layer. Reference numerals 102U and 102L denote a display portion corresponding to the light source 104 and a display portion corresponding to the light absorption layer 105 of the variable transmission polarization axis element 102, respectively.

Here, the display portions 102U and 102L have a so-called two-screen configuration that can be displayed independently. That is, the transmission polarization axis variable element 102 includes a plurality of signal electrodes.
(In the figure, the symbol S is attached to one place as a representative.) A group is formed, but at the boundary between the display portions 102U and 102L,
The upper and lower parts are separated and are respectively drawn to the upper and lower ends. Then, a group of several scanning electrodes (in the figure, the symbol C is given at one place as a representative) is formed, and is drawn to the left end. Then, the intersection of the signal electrode and the scanning electrode becomes a display pixel. In this embodiment, a TN liquid crystal element is used. However, other liquid crystal elements may be used. Further, a so-called active matrix liquid crystal element in which a switch element and a pixel electrode are provided at the intersection of a signal electrode and a scanning electrode may be used. Further, the shape of the intersection between the signal electrode and the scanning electrode is changed to a specific display pattern (for example, a plurality of 7
(Segment display).

In FIG. 6, reference numerals 601U and 601L denote circuits for applying drive waveforms to the signal electrode groups drawn up and down, respectively.
(Hereinafter, referred to as X driver), 602U, 602
L is a circuit for applying a drive waveform to the scanning electrode group (hereinafter, referred to as a Y driver). The Y driver 602U is connected to the display unit 102U, and the Y driver 602L is connected to the display unit 10U.
A drive waveform is applied to a scan electrode group corresponding to 2L.

A control circuit 603 is an X driver 601.
A control signal for controlling the operation of the U and 601L and the Y drivers 603U and 602L is generated.

A display control signal 604 is a control circuit 603.
To enter.

The control circuit 603 changes the control signals given to the X drivers 601U and 601L and the Y drivers 603U and 603L according to the state of the display control signal 604.

For example, when the state of the display control signal 604 is a certain state (this state is “3”), a control signal for displaying both the display portion 102U and the display portion 102L is generated, and the display control signal 604 is generated. State is some other state (this is "
At the time of "1"), a control signal for displaying the display portion 102U and not displaying the display portion 102L is generated, and the state of the display control signal 604 is set to another certain state (set to "0"). In the case of ()), a control signal for not displaying both the display portion 102U and the display portion 102L is generated.

Here, the state of the display control signal 604 is "1".
In this case, it is desirable that the voltages output from the X driver 601L and the Y driver 603L are all the same voltage. When the state of the display control signal 604 is "0", the X driver 601U and the Y driver 603U are additionally provided. Are desirably the same voltage, and in this embodiment, it is assumed that such a control signal is output.

Reference numeral 605 denotes a power supply circuit for the light source 104.
A lighting control signal 606 is input to the power supply circuit 605.

When there is a state of the lighting control signal 606 (this state is set to “1”), the power supply circuit 605 is activated and the light source 104 is turned on. When the state of the lighting control signal 606 is some other state (this state is set to “0”), the power supply circuit 605 becomes inactive and the light source 104
Turn off the light.

The display device of the present invention has the above configuration.

Thus, in a dark place, the lighting control signal 606
Is set to “1”, the light source 104 is turned on. Therefore, the display portion 102U is a transmissive display.

Here, the display control signal may be set to "3" to display on the entire surface, but the display portion 102L is hardly seen because it is a dark place. Therefore, the display portion 102L
It is more preferable to set the display control signal to "1" and drive and display only the display portion 102U in order to reduce the power for driving.

Further, under bright external light, the lighting control signal 6
By setting 06 to “0”, the light source 104 is turned off.

By setting the display control signal to "3", reflection display is performed on the display portions 102U and 102L.

Here, when much information is not required, the power consumption can be reduced by setting the display control signal to "1".

As described above, according to the display device of this embodiment, the power consumed by the display device can be minimized.

In this embodiment, an example using the display element 100 described in the first embodiment is described, but the display element described in the second to sixth embodiments may be used. For example, when the display element 300 of FIG. 3 described in the second embodiment is used, a power supply for turning on the light source 301 of FIG. 3 may be prepared and controlled. That is, when displaying the whole image in a dark place, the light source 104
And the light source 301 may be turned on.

The same applies to the display elements described in the third to sixth embodiments. However, since the specific use and control method can be easily realized from the above description, the description is omitted.

As described above, a display device using the display element described in Embodiments 1 to 6 can be realized, and the effects described in Embodiments 1 to 6 can be obtained.

[Embodiment 8] This embodiment is an embodiment relating to an electronic apparatus of the present invention.

The liquid crystal device described in Embodiment 7 is bright and consumes low power. When viewed in a dark place, there are few portions to be displayed in a transmissive manner, and the power consumed by the light source can be minimized. Therefore, it is suitable for display means such as a battery-powered portable information device which is often carried around, and particularly suitable for a portable information device having a communication function.

Therefore, a portable information device having this communication function will be described as an example of a typical electronic device.

FIG. 7 is a block diagram of a portable information device having a communication function.

In the figure, reference numeral 600 enclosed by a broken line denotes the display device 600 of FIG. 6. The components of the display device 600 are the same as those of FIG. The components are not shown in the drawings.

Reference numeral 701 denotes a central control unit (hereinafter referred to as a CPU).
Call. ), 702 is an antenna, 703 is a transmitting / receiving circuit,
Reference numeral 704 denotes a read-only memory (hereinafter, referred to as a ROM),
Reference numeral 705 denotes a read / write memory (hereinafter, referred to as RAM),
Reference numeral 706 denotes an input device such as a keyboard; 707, a sound generating element (or a vibrating element) such as a speaker; and 708, a removable recording medium such as a floppy disk.

The structure of the electronic device (portable information device having a communication function) of the present invention is as described above.

Here, the operation will be briefly described.

First, when there is no radio wave transmitted to the electronic device, the display control signal 606 output by the CPU 701 is "1", and the lighting control signal 606 output by the CPU 701 is "0".

That is, only the display portion 102U is performing display. The display content is, for example, a time display or the like.

Here, when it is dark at night or in a car,
By performing a predetermined operation 1 on the input device 706 and setting the lighting control signal 606 output by the CPU 701 to “1”, the power source 605 for the light source becomes active, the light source 104 (not shown) is turned on, and the display portion is displayed. Only 102U is in the transmissive display, and the time and the like can be seen.

Here, when the user has finished watching, the user performs a predetermined operation 2 on the input device 706 to set the lighting control signal 606 output by the CPU 701 to “0”, thereby setting the power source 605 for the light source.
Becomes inactive and the light source 104 is turned off.

Next, when there is a radio wave transmitted toward the electronic device, the antenna 702 and the transmission / reception circuit 703 are provided.
And receives it and passes the received content to the CPU 701.

Then, the CPU 701 notifies that the call has arrived by sounding the sound using the sound emitting element 707.

At the same time, the CPU 701
U is displayed, but only a part of the received content, for example, only the title is displayed.

The user can see the title, for example.

Here, when it is dark at night or in a car,
By performing a predetermined operation 1 on the input device 706 and setting the lighting control signal 606 output by the CPU 701 to "1", only the display portion 102U becomes the transmissive display, and the title can be viewed.

If it is necessary to see all the received contents from the contents of the title, the vehicle is turned on by turning on the room light of the car, etc.
01 is set to "0" for the lighting control signal 606 output by the CPU 70.
The display control signal 604 output by 1 is set to "3". Then, the power source 605 for the light source is deactivated, the light source 104 is turned off, and all of the display portions 102U and 102L are of a reflection type display, so that all the received contents can be viewed.

After the end of the viewing, a predetermined operation 4 is performed on the input device 706 to set the display control signal 604 to “1”.

Then, only the display portion 102U is displayed, but the display content is switched to the display of the original time, for example.

If the user wants to save the received content, the user can perform a predetermined operation 5 for the saving using the input device 706 and save the received content on the removable recording medium 708.

The above operation is performed.

These operations are controlled by a program stored in the ROM 704, and the RAM 705 is used to temporarily store data and programs necessary for these controls.

The above operation is performed.

Therefore, only display portion 102U is always displayed, and display portion 102L is displayed as needed. Further, only the display portion 102U can perform a transmissive display as needed. In other words, the light source corresponding to that portion emits light.

As described above, only the necessary minimum information is
It is possible to always perform reflective display and display as much information as necessary. In a dark place, only necessary minimum information can be displayed in a transmission type.

In this embodiment, the display device 600 shown in FIG. 6 including the display device 100 shown in FIG. 1 is used as an example. For example, the display device shown in FIG. It goes without saying that a display device including the display device 300 can be used. In this case, it is possible to perform the transmissive display on the entire surface as needed in a dark place.

Further, the effects described in the third to sixth embodiments can be obtained by using the display device including the display element described in the third to sixth embodiments.

Note that the CPU 701 issues a sound by the sounding element 707 to notify that the call has been received, and at the same time, the power source 6 for the light source
05 may be automatically activated, or may be selectively set as such.

When there is no radio wave transmitted to the electronic device and the time display or the like is unnecessary, the display control signal 604 is set to "0" so that the driving of the display portion 102L can be stopped. It does not matter whether or not such setting can be selectively performed.

Further, various circuits constituting this embodiment may be selected according to the use of the electronic device.

For example, in this embodiment, an antenna 702 and a transmission / reception circuit 703 are provided as wireless communication functions.
To provide a wired communication function, a transmission / reception circuit for wired communication may be provided.

Further, a vibration element for causing the body to feel vibration may be used instead of the sound generating element 707, or may be used together.

Further, the removable recording medium 708 may be omitted depending on the application.

It is of course also possible to add other functions. For example, a current position detection circuit or the like required to have a navigation function may be added.

Ninth Embodiment In the eighth embodiment, the shape of the input device 706 may be any shape.

For example, one or a plurality of transparent electrodes are formed on the inner surfaces of a pair of transparent members facing each other, and when the transparent members are pressed from one side, the transparent electrodes come into contact with each other to conduct electricity. It may be a key.

FIG. 8 is a diagram showing the display device 600 of the electronic apparatus according to the eighth embodiment in which a part of the input display 706 of FIG. 7 is replaced with touch keys, and the display contents thereof.

(A) to (d) of the figure show the operation procedure in order from top to bottom.

In FIG. 8, reference numeral 600 denotes the display device 600 shown in FIG.
Reference numerals 102U and 102L denote upper and lower display portions of the display device 600, respectively.

Reference numeral 800 denotes a touch key, which is indicated by white cross hatching.

[0189] The touch key 800 has a front surface so as to cover at least a part of the display portion 102U of the display device 600.
(Front side in the figure). In addition, you may arrange | position so that the whole display parts 102U and 102L may be covered, for example.

Here, the numbers relating to the configuration are given as representatives only in FIG. 8 (a).

Reference numerals 801 to 806 denote display contents.

First, FIG. 8A shows a state where there is no radio wave transmitted to the electronic device.

Only display portion 102U performs display. Then, the display content 801 is displayed. That is, the time “AM7: 45” is displayed.

Next, when there is a radio wave transmitted toward this electronic device, the state changes to the state shown in FIG.
That is, the display contents 802 and 803 are displayed.

Here, the display content 802 displays the title “urgent” of the received content.

Accordingly, the user can see the title.

At the same time, the display content 803 is displayed at a position corresponding to the touch key 800, and "all recovery" indicating the operation is displayed. Here, “all restoration” means two operations of “switch to full display / return”, respectively.

Here, when the portion of the touch key 800 on which “Return” is displayed is pressed, the display returns to the display state shown in FIG. That is, there is no need to see the full text from the title of the received content.

On the other hand, touch the part displayed as "all"
When the key 800 is pressed, the state changes to the state shown in FIG.
That is, the display contents 804 and 805 are displayed.

[0200] Here, the display content 804 displays the full text of the received content, "Fire should be <Omitted>Express."

Therefore, the user can see the whole sentence.

At the same time, the display content 805 is displayed at a position corresponding to the touch key 800, and "return" indicating the operation is performed.
Is displayed. Here, “return” means “return” operation.

Then, when the touch key 800 is pressed on the portion displaying "Return", the state changes to the state shown in FIG. 8D. That is, the display content 806 is displayed. Here, the display content 806 is a display of time “AM7: 46”. That is, FIG.
It returns to the state of (a).

The operation is as described above.

Here, the display elements described in the first to sixth embodiments perform bright display, so that even if the touch key 800 is placed, the visibility is not so deteriorated, and such a configuration is possible.

Therefore, the same effects as those of the electronic apparatus according to the eighth embodiment can be obtained, the operation can be performed with the touch keys on which the operation instructions are displayed, the operability is improved, and a part of the input device 706 is partially used. Since the touch keys are used, other switches and the like constituting the input device 706 can be reduced correspondingly, and the degree of freedom in external design and the like of the electronic device can be increased, and the electronic device can be provided with good appearance and good handling.

[0207]

According to the display element of the first aspect of the present invention, it is possible to perform a transmissive display only on a portion illuminated by the first light source, and to display a minimum necessary information in a dark place. And the light amount and power of the first light source for display can be reduced.

According to the display element of the present invention, a large amount of information can be displayed in a dark place by turning on the first light source and the second light source as necessary.

According to the display element of the present invention, a part of the external light can be converted into electric power by the photoelectric conversion element under bright external light. Power can be reduced.

According to the display element of the present invention, the transmission type display can be performed only on the portion irradiated by the third light source, and the minimum necessary information is displayed in a dark place. This makes it possible to reduce the amount of light and power of the first light source for display. Further, in the case of the reflection type display, a display which is easy to see without a seam in the display can be provided.

According to the display element of the present invention, a large amount of information can be displayed in a dark place by turning on the fourth light source as necessary. Also, at this time, a display that is easy to see without a seam in the display can be provided.

According to the display element of the present invention, the area of the photoelectric conversion element can be increased, and a part of the external light can be converted into more electric power. Thus, power consumption can be further reduced.

According to the display element of the present invention, a controllable and inexpensive hyperpolarization axis changing means can be obtained.

According to the display element of the present invention described in claim 8, in the display element of claim 7, the transmission polarization axis changing means is a TN liquid crystal element, an STN liquid crystal element, or an F-STN liquid crystal element.
It is a liquid crystal element or an ECB liquid crystal element.

In this way, more favorable response speed and contrast can be obtained.

According to the display element of the ninth aspect of the present invention, the first polarized light separating means which can be easily manufactured can be obtained.

According to the display device of the present invention, the necessary minimum information can be displayed in a transmissive display in a dark place, and as much information as possible can be displayed. As a result, it is possible to reduce the power of the light source and the power required to control the transmission polarization axis varying unit.

According to the electronic device of the present invention, it is possible to display the minimum necessary information and a large amount of information by the switching means at the convenience of the user. Power can be suppressed, and the battery life can be prolonged, particularly in battery-powered electronic devices.

According to the electronic device of the present invention, the operability of the switching means is improved, and the appearance of the electronic device is improved.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a schematic cross section and an optical path of a display element according to a first embodiment.

FIG. 2 is a schematic cross-sectional view of the display element 100 according to the first embodiment and a diagram illustrating another optical path.

FIG. 3 is a schematic sectional view of a display element 300 according to a second embodiment.

FIG. 4 is a block diagram of a display device 400 according to a third embodiment.

FIG. 5 is a schematic sectional view of a display element 500 according to a fifth embodiment.

FIG. 6 is a block diagram of a display device 600 according to a seventh embodiment.

FIG. 7 is a block diagram of a portable information device having a communication function according to a seventh embodiment.

8 is a diagram illustrating a display device 600 of an electronic apparatus according to an eighth embodiment, in which a part of the input display 706 in FIG. 7 according to the ninth embodiment is replaced with touch keys, and a display content thereof.

[Explanation of symbols]

100 ··· Display element. 101 ··· Polarized light separator, polarizing plate. 102 ... Transmission polarization axis variable optical element (TN liquid crystal element). 102a ... board. 102b ... board. 102c ··· liquid crystal layer (state where voltage is not applied) 102d ··· liquid crystal layer (state where voltage is applied) 103 ··· polarization separator. 104 ... light source. 105 ... light absorption layer. 106... (1/4) wavelength plate. 107 ... light path. 108 ··· Optical path. 109 ··· Optical path. 110 ... light path.

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FI G02F 1/1335 520 G02F 1/1335 520 530 530 G09F 9/35 321 G09F 9/35 321 (72) Inventor Yutaka Ozawa Suwa, Nagano Prefecture 3-5-5 Yamato-shi, Seiko Epson Corporation

Claims (12)

[Claims] 1. A transmission polarization axis variable means having a variable transmission axis, a first polarization separation means disposed on one side of the transmission polarization axis variable means, and a second polarization separation means disposed on the other side of the transmission polarization axis variable means. A second polarized light separating means and a first polarized light separating means disposed on the opposite side of the transmission polarized light axis varying means with respect to the second polarized light separating means.
And a second optical element, wherein the first polarization splitting means is incident on the transmission polarization axis variable means from the side opposite to the second polarization splitting means. The linearly polarized light component in the first predetermined direction of the light thus transmitted is transmitted as linearly polarized light to the transmission polarization axis variable unit side, and is incident on the transmission polarization axis variable unit from the side opposite to the second polarization separation unit. The linearly polarized light component in the second predetermined direction orthogonal to the first predetermined direction is not transmitted to the transmission polarization axis changing unit side of the light, and the second polarized light component is transmitted to the transmission polarization axis changing unit. The linearly polarized light component in the first predetermined direction out of the light incident from the polarized light separating means side is transmitted as linearly polarized light to the opposite side to the second polarized light separating means, and the second polarized light is transmitted to the transmitted polarization axis changing means. 2 from the polarization separation means side A polarized light separating means does not transmit said second predetermined linear polarization component on the opposite side of the second polarized light separating means of the light, the second polarized light separating means,
Of the light incident from the transmission polarization axis changing unit side,
Is transmitted to the first optical element and the second optical element side, and the linearly polarized light component in a fourth predetermined direction orthogonal to the third predetermined direction is transmitted. The first optical element does not transmit the polarized light component in the fourth predetermined direction of the light reflected from the polarization axis changing unit and incident from the first optical element and the second optical element. Polarization splitting means capable of emitting linearly polarized light in the third predetermined direction to the transmission polarization axis changing means side with respect to light incident from the side, wherein the first optical element is a first light source, A display element, wherein the second optical element is a light absorbing member. 2. The display device according to claim 1, wherein said second optical element is a second light source. 3. The display element according to claim 1, wherein said second optical element is a photoelectric conversion element. 4. A transmission polarization axis changing means, said first polarization separation means, said second polarization separation means, and a second polarization separation means are disposed on the opposite side of said transmission polarization axis change means. A display device comprising at least a third optical element, a third polarization element, and a third light source disposed between the second optical element and the third optical element. And a light absorbing member. 5. The display device according to claim 4, wherein said third optical element is a fourth light source. 6. The display element according to claim 4, wherein said third optical element is a photoelectric conversion element. 7. The display element according to claim 1, wherein said transmission polarization axis changing means is a liquid crystal element. 8. A display device according to claim 7, wherein said transmission polarization axis changing means comprises a TN liquid crystal element, an STN liquid crystal element,
-A display element characterized by being an STN liquid crystal element or an ECB liquid crystal element. 9. A display device according to claim 1, wherein said first polarization splitting means is a polarizing plate. 10. A display device according to claim 1, wherein the display device has a function of performing at least two of a mode for displaying a part of the display device and a mode for displaying the entire surface. Display device. 11. An electronic apparatus comprising: the display device according to claim 10; and switching means for switching between the two modes of the display device. 12. The electronic device according to claim 11, wherein at least a part of said switching means is arranged in said display device portion.