JP2000056294A - Liquid crystal display device and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make an image display with high contrast and high quality both in a reflective display mode and in a transmissive display mode in a liquid crystal display device exchangeable between a reflective display and a transmissive display by suppressing a double image due to parallax and a blot on the display. SOLUTION: When a backlight 15 is turned on in the dark, as light from a light source passes through a semitransparent reflection plate 7 via a polarizing plate 12 and a phase difference plate 14, and it is guided into a liquid crystal layer 3 to perform a transmissive display. In the sun since an incident external light passing through a polarizing plate 11, a phase difference plate 13 and the liquid crystal layer 3 is reflected on the semitransparent reflection plate 7, a reflective display is performed. A driving voltage is switched correspondingly to either a reflective display mode or a transitive display mode in order to apply a driving voltage most suited to reflectance and transmittance characteristics of the driving voltage to liquid crystal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a liquid crystal device, and more particularly, to a liquid crystal device capable of switching and displaying a reflection type display and a transmission type display, and a technique of an electronic apparatus using the liquid crystal device. Belongs to the field.

[0002]

2. Description of the Related Art Conventionally, reflection type liquid crystal devices have been frequently used for portable devices and auxiliary display units of the devices because of their low power consumption. There was a problem that the display could not be read in a dark place. For this reason, there has been proposed a liquid crystal device of a type in which external light is used in a bright place similarly to a normal reflection type liquid crystal device, but in a dark place, the display can be visually recognized by an internal light source. This is disclosed in JP-A-57-049271, JP-A-57-049271, and JP-A-57-049271.
As described in Japanese Patent No. 049271, a polarizing plate, a transflective plate, and a backlight are sequentially arranged on the outer surface of the liquid crystal panel opposite to the observation side. In this liquid crystal device, when the surroundings are bright, external light is taken in and reflective display is performed using light reflected by the semi-transmissive reflecting plate. When the surroundings are dark, the backlight is turned on and the semi-transmissive reflecting plate is turned on. A transmissive display in which the display can be visually recognized by the light transmitted through is provided.

As another liquid crystal device, there is one disclosed in Japanese Patent Application Laid-Open No. Hei 8-292413 in which the brightness of a reflective display is improved. This liquid crystal device has a configuration in which a transflective plate, a polarizing plate, and a backlight are sequentially arranged on the outer surface of the liquid crystal panel opposite to the observation side. When the surroundings are bright, external light is taken in and reflective display is performed using the light reflected by the semi-transmissive reflector. When the surroundings are dark, the backlight is turned on and the polarizing plate and the semi-transmissive reflector are transmitted. A transmissive display in which the display is visually recognizable by the applied light is performed. With such a configuration, since there is no polarizing plate between the liquid crystal cell and the transflective plate, a reflective display brighter than the above-described liquid crystal device can be obtained.

[0004]

However, in the liquid crystal device described in JP-A-8-292413, since a transparent substrate is interposed between the liquid crystal layer and the transflective plate, double reflection or display is not possible. There is a problem that blurring occurs.

Further, with the development of portable equipment and OA equipment in recent years, colorization of liquid crystal display has been required, and there are cases where colorization is necessary even in equipment using a reflection type liquid crystal device. Many. However, in the method in which the liquid crystal device and the color filter described in the above publication are combined, the transflective plate is disposed behind the liquid crystal panel. There is a problem in that a thick transparent substrate of the liquid crystal panel is interposed, and a double reflection or blurring of display occurs due to parallax, so that sufficient coloring cannot be obtained.

To solve this problem, Japanese Patent Laid-Open No. 9-2
Japanese Patent No. 58219 proposes a reflective color liquid crystal device in which a reflector is arranged so as to be in contact with a liquid crystal layer. However, in this liquid crystal device, when the surroundings are dark, the display cannot be recognized.

On the other hand, Japanese Patent Application Laid-Open No. Hei 7-318929 proposes a transflective liquid crystal device in which a pixel electrode serving also as a transflective film is provided on the inner surface of a liquid crystal cell. However, in this liquid crystal device, the liquid crystal drive is performed using the same driving device (for example, a so-called X driver circuit or Y driver circuit) during both the reflective display and the transmissive display, and the driving corresponding to the same image data is performed. The voltage is constant in both reflective display and transmissive display. However, according to the study of the present inventors, in general, in this type of transflective liquid crystal device, the characteristics of the reflectance with respect to the liquid crystal driving voltage during the reflective display and the transmittance with respect to the liquid crystal driving voltage during the transmissive display are generally considered. Does not match the characteristics of As a result,
In a liquid crystal device disclosed in Japanese Patent Application Laid-Open No. Hei 7-318929, if a driving device sets a liquid crystal driving voltage with respect to the gradation of image data so as to obtain good contrast and display density at the time of reflection type display, at the time of transmission type display, Good contrast and display density cannot be obtained. Conversely, if the driving device sets the liquid crystal driving voltage for the gradation of image data so that a good contrast and display density can be obtained at the time of transmission type display, a good contrast and display density can be obtained at the time of reflection type display. There is a problem that can not be.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and in a liquid crystal device capable of switching between a reflective display and a transmissive display, double reflection due to parallax and display bleeding do not occur. It is an object of the present invention to provide a transflective liquid crystal device capable of displaying a high-contrast, high-quality image both at the time of pattern display and at the time of transmissive display, and an electronic apparatus using the liquid crystal device.

[0009]

In order to solve the above-mentioned problems, a first liquid crystal device according to the present invention has a pair of transparent first and second substrates and is sandwiched between the first and second substrates. A second electrode comprising a liquid crystal layer, a transparent first electrode formed on the liquid crystal layer side surface of the first substrate, and a semi-transmissive reflective layer formed on the liquid crystal layer side surface of the second substrate. A lighting device disposed on the side of the second substrate opposite to the liquid crystal layer, and applied to the liquid crystal layer via the first and second electrodes when the lighting device is turned on and off. Driving means for driving the first and second electrodes so that liquid crystal driving voltages are different for the same image.

According to the first liquid crystal device of the present invention, at the time of reflective display, the transflective layer (second electrode) reflects external light incident from the first substrate side to the liquid crystal layer side. At this time, since the transflective layer (second electrode) is disposed on the liquid crystal layer side of the second substrate, there is almost no gap between the liquid crystal layer and the transflective layer (second electrode). No double reflection of the display or blurring of the display due to parallax occurs. On the other hand, at the time of transmissive display, the light source light emitted from the illumination device and incident from the second substrate side is transmitted to the liquid crystal layer side via the semi-transmissive reflection layer (second electrode). Therefore, a bright display can be performed in a dark place using the light from the light source.

[0011] In particular, the first driving means makes the first liquid crystal driving voltage applied to the liquid crystal layer via the first and second electrodes different between the lighting and non-lighting of the illuminating device so as to be different for the same image. And the second electrode is driven. That is, in general, in a transflective liquid crystal device, the characteristics of the reflectance with respect to the liquid crystal driving voltage during the reflective display and the characteristics of the transmittance with respect to the liquid crystal driving voltage during the transmissive display do not match.
By making the liquid crystal drive voltage different as in the present invention, the illumination device can be driven while driving the liquid crystal with a drive voltage adapted to the reflectance characteristic with respect to the drive voltage in the reflection type display at the time of reflective display in which the illumination device is not lit. When the display is turned on, the liquid crystal can be driven by a drive voltage suitable for a transmittance characteristic with respect to a drive voltage in the transmission display. In particular, it is very useful to change the level of the voltage applied to the liquid crystal for halftone display between white display and black display between the reflective display and the transmissive display.

In order to solve the above-mentioned problems, a second liquid crystal device according to the present invention comprises a pair of transparent first and second substrates, and the first and second substrates.
A liquid crystal layer sandwiched between the first and second substrates, a transparent first electrode formed on the liquid crystal layer side of the first substrate, and a transparent first electrode formed on the liquid crystal layer side of the second substrate. A transflective layer, a transparent second electrode formed between the transflective layer and the liquid crystal layer, an illuminating device disposed on the second substrate on a side opposite to the liquid crystal layer; The first and second electrodes are driven such that liquid crystal driving voltages applied to the liquid crystal layer via the first and second electrodes are different for the same image when the device is lit and when the device is not lit. And a driving means.

According to the second liquid crystal device of the present invention, at the time of reflective display, the transflective layer reflects external light incident from the first substrate side to the liquid crystal layer side. At this time, since the transflective layer is disposed on the liquid crystal layer side of the second substrate, there is almost no gap between the liquid crystal layer and the transflective layer. No display bleeding occurs. On the other hand, at the time of transmissive display, light source light emitted from the illumination device and incident from the second substrate side is transmitted to the liquid crystal layer side via the semi-transmissive reflective layer. Therefore, a bright display can be performed in a dark place using the light from the light source.

In particular, when the lighting device is turned on and not turned on by the driving means, the first liquid crystal driving voltage applied to the liquid crystal layer via the first and second electrodes is different for the same image. And the second electrode is driven. As a result, similarly to the case of the above-described first liquid crystal device of the present invention, the liquid crystal is driven by a drive voltage suitable for the reflectance characteristic with respect to the drive voltage in the reflective display in the reflective display in which the lighting device is turned off. In the case of a transmissive display in which the illumination device is lit while the liquid crystal is being driven, it is possible to drive the liquid crystal with a drive voltage that matches the reflectance characteristic with respect to the drive voltage in the transmissive display.

The driving methods of the first and second liquid crystal devices include a passive matrix driving method and a TFT (Thin Filtration) method.
m Diode) Active matrix drive system, TFD (Thi
n Film Diode) Various known driving methods such as an active matrix driving method and a segment driving method can be adopted. The display mode may be either a normally black mode or a normally white mode.However, if the former is adopted, the liquid crystal device is driven so as to be in a dark state when not driven. Light leakage from pixels or dots that are not driven can be suppressed, and a transmissive display with high contrast can be obtained. Further, at the time of the reflective display, reflected light unnecessary for display from between pixels or between dots can be suppressed, so that a display with high contrast can be obtained.

In one aspect of the first and second liquid crystal devices of the present invention, the transflective layer is a reflective film having an opening in each pixel through which light from the illumination device can pass. Consists of

According to this aspect, since the light from the illumination device can be transmitted through each of the pixels through the opening provided in the transflective layer, a transmissive display using the illumination device can be performed. . Further, since the external light is reflected via the liquid crystal by the reflective film portion that is out of the opening, the reflection type display using the external light can be performed. Note that, as such an opening, for example, a rectangular slit, a fine opening, a hole defect, a pit defect, or the like which is regularly arranged or irregularly dotted on the surface of the reflection film may be used. Alternatively, a plurality of reflective films may be formed in a stripe shape or an island shape so that light is transmitted through an opening between adjacent reflective films. As a material of the reflection film, a metal whose main component is Al (aluminum) is used.
The material is not particularly limited as long as it is a metal such as (silver) that can reflect external light in the visible light region. For example, if the reflective film is configured to contain 95% by weight or more of Al and have a layer thickness of 10 nm to 40 nm, the transmittance is 1% to 40% and the reflectance is 5%.
A semi-transmissive reflective electrode of 0% or more and 95% or less can be manufactured.

On the other hand, the diameter of the opening is 0.01 μm or more and 2
It is preferably 0 μm or less. By doing so, it is difficult for a human to recognize, and it is possible to simultaneously realize the reflective display and the transmissive display while suppressing the deterioration of the display quality caused by the provision of the opening. The opening is preferably formed with an area ratio of 5% to 30% with respect to the reflective film. By doing so, it is possible to suppress a decrease in brightness of the reflective display, and to realize a transmissive display by light introduced into the liquid crystal layer through the opening of the reflective film. Such an opening can be easily formed by a photo step / developing step / separation step using a resist.

In particular, in the case of the first liquid crystal device of the present invention, the transflective layer (second electrode) made of such a reflective film has a function of reflecting external light and a function of applying a voltage to the liquid crystal. Therefore, as compared with the case where the reflective film and the pixel electrode are separately formed, the device configuration, the manufacturing, and the design are more advantageous, and the cost can be reduced. On the other hand, in the case of the first liquid crystal device of the present invention, since there is no need to provide an opening in the transparent second electrode, device reliability and manufacturing yield of the second electrode are improved.

In another aspect of the first and second liquid crystal devices of the present invention, each of the driving means includes a first supply means for supplying a voltage to the first electrode, and a voltage supplied by the first supply means. And a first control unit for controlling the first supply unit so as to switch to a setting for reflective display according to the non-lighting and to switch to a setting for transmissive display according to the lighting.

According to this aspect, the voltage is supplied to the first electrode (for example, the scanning line) by the first supply means (for example, the Y driver circuit), and the voltage is supplied under the control of the first control means. The applied voltage is switched to a setting for reflective display according to non-lighting of the lighting device, and is switched to a setting for transmissive display according to lighting of the lighting device. Therefore, at the time of the reflective display and the transmissive display, the liquid crystal can be driven by the drive voltage suitable for the reflectance characteristic and the transmittance characteristic with respect to the drive voltage.

In this aspect, the lighting device further comprises lighting switching means for switching between the lighting and the non-lighting, and the first control means synchronizes with the switching operation by the lighting switching means. The voltage supplied by the supply means may be switched to a setting for reflective display or a setting for transmissive display.

In another aspect of the first and second liquid crystal devices of the present invention, the driving means includes a second supply means for supplying a voltage to the second electrode, and a voltage supplied by the second supply means. And second control means for controlling the second supply means so as to switch to a setting for reflective display according to the non-lighting and to a setting for transmissive display according to the lighting.

According to this aspect, the voltage is supplied to the first electrode (for example, the data line) by the second supply unit (for example, the X driver circuit), and this supply is performed under the control of the first control unit. The applied voltage is switched to a setting for reflective display according to non-lighting of the lighting device, and is switched to a setting for transmissive display according to lighting of the lighting device. Therefore, at the time of the reflective display and the transmissive display, the liquid crystal can be driven by the drive voltage suitable for the reflectance characteristic and the transmittance characteristic with respect to the drive voltage.

In this aspect, the second supply means supplies a voltage having an effective value of a magnitude corresponding to a gradation level indicated by gradation data to the second electrode, and the second control means
The setting of each magnitude of the effective value for each gradation level,
The second supply unit may be controlled so as to switch to a setting for reflective display according to the non-lighting and to switch to a setting for transmission display according to the lighting.

According to this structure, under the control of the second control means, the setting of each magnitude of the effective value for each gradation level is switched to the setting for the reflective display according to the non-lighting, and the other illumination is performed. The setting for the transmission type display is switched according to the lighting of the device. Then, a voltage having an effective value corresponding to the gradation level indicated by the gradation data is supplied to the second electrode by the second supply means. Therefore, it is possible to drive the liquid crystal with a good driving voltage particularly over the entire gradation range.

In another aspect of the first and second liquid crystal devices according to the present invention, a color filter is further provided between the transflective layer and the first substrate.

According to this aspect, it is possible to perform a reflection type color display using external light and a transmission type color display using an illumination device. The color filter is 380 nm or more and 780
It preferably has a transmittance of 25% or more for all light in the wavelength range of nm or less. By doing so, bright reflective color display and transmissive color display can be realized.

In another aspect of the first and second liquid crystal devices according to the present invention, the transflective layer has irregularities.

According to this aspect, the mirror feeling of the reflective electrode can be eliminated by the unevenness, and the reflective electrode can be seen as a scattering surface (white surface). In addition, a display with a wide viewing angle can be performed by scattering due to unevenness. This uneven shape can be formed by using a photosensitive acrylic resin or the like for the base of the reflective electrode, or by roughening the base glass substrate itself with hydrofluoric acid. It is desirable to further form a transparent flattening film on the uneven surface of the reflective electrode and to flatten the surface facing the liquid crystal layer (the surface on which the alignment film is formed) from the viewpoint of preventing poor alignment of the liquid crystal. .

According to another aspect of the invention, there is provided an electronic apparatus including the above-described liquid crystal device of the invention.

According to the electronic apparatus of the present invention, a transflective liquid crystal device or a transflective liquid crystal device capable of switching between a reflective display and a transmissive display without causing double reflection due to parallax or blurring of display is provided. Various types of electronic equipment using a color liquid crystal device can be realized. Such an electronic device can realize particularly high-contrast and high-quality display regardless of ambient light in a bright place or a dark place.

[0033]

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

(First Embodiment) A first embodiment of the liquid crystal device according to the present invention will be described with reference to FIGS. FIG.
FIG. 1A is a schematic longitudinal sectional view showing a structure of a first embodiment of the present invention, and FIG. 1B is a schematic plan view of the first embodiment shown in FIG. 2 to 6 are enlarged plan views showing various specific examples of openings provided in the reflective electrode in the first embodiment, and FIG. 7 is a reflection type display with respect to a drive voltage in the liquid crystal device of the first embodiment. FIG. 4 is a characteristic diagram showing a characteristic of a reflectance R at the time of transmission and a characteristic of a transmittance T at the time of transmission type display. In FIG. 1 (b), FIG.
The color filter and the black matrix layer shown in FIG. 1 are omitted, and only three stripe-shaped electrodes are shown for convenience of description. However, in an actual liquid crystal device, a much larger number of stripe-shaped electrodes are used. Is provided.
Although the first embodiment basically relates to a simple matrix type liquid crystal display device, the same configuration can be applied to an active matrix type device, another segment type device, and other liquid crystal devices. It is possible.

As shown in FIGS. 1A and 1B, in the first embodiment, a liquid crystal layer 3 is sealed between two transparent substrates 1 and 2 by a frame-shaped sealing material 4. Liquid crystal cell is formed. The liquid crystal layer 3 is composed of a nematic liquid crystal having a predetermined twist angle. A color filter 5 is formed on the inner surface of the front transparent substrate 1, and three color layers of R (red), G (green), and B (blue) are arranged in the color filter 5 in a predetermined pattern. ing. A transparent protective film 10 is coated on the surface of the color filter 5, and a plurality of stripe-shaped transparent electrodes 6 are formed on the surface of the protective film 10 by IT.
It is formed of an O (Indium TinOxide) film or the like.
An alignment film 9 is formed on the surface of the transparent electrode 6 and rubbed in a predetermined direction.

On the other hand, on the inner surface of the rear transparent substrate 2, a plurality of stripe-shaped reflective electrodes 7 formed for each color layer of the color filter 5 are arranged so as to intersect the transparent electrodes 6. In the case of an active matrix type device including a TFD element and a TFT element, each reflective electrode 7 is formed in a rectangular shape, and is connected to a wiring via the active element. The reflective electrode 7 is formed of Cr, Al, or the like, and its surface is a reflective surface that reflects light incident from the transparent substrate 1 side. An alignment film 19 similar to the above is formed on the surface of the reflection electrode 7. The reflection electrode 7 has
Many openings 7b having a diameter of 2 μm (see FIG. 1B) are provided, and the total area of the openings 7b is provided at a rate of about 10% of the total area of the reflection electrode 7.

Here, referring to FIGS.
Various examples of the opening 7b will be described.

First, as shown in FIG. 2, a stripe-shaped transparent electrode 802 (corresponding to the transparent electrode 6 in FIG. 1) formed on the upper transparent substrate is formed on the lower transparent substrate. The stripe-shaped reflective electrode 802 (the reflective electrode 7 in FIG. 1)
), A rectangular slit 803 (the opening 7b in FIG. 1).
May be formed. The rectangular slit 8
03 may be a square, a rectangle, another polygon or a circle. Furthermore, the arrangement and the orientation may be regularly arranged as long as at least one opening is provided in each dot (that is, in FIG. 2, a region where the transparent electrode 801 and the reflective electrode 802 intersect). , May be irregularly dotted.

As shown in FIG. 3, a stripe formed on the lower transparent substrate is opposed to a stripe-shaped transparent electrode 601 (corresponding to the transparent electrode 6 in FIG. 1) formed on the upper transparent substrate. A minute defect portion 603 (corresponding to the opening 7b in FIG. 1) such as a hole defect or a dent defect scattered irregularly is formed on the reflection electrode 602 (corresponding to the reflection electrode 7 in FIG. 1). Is also good.

As shown in FIG. 4, a stripe formed on the lower transparent substrate is opposed to the stripe-shaped transparent electrode 301 (corresponding to the transparent electrode 6 in FIG. 1) formed on the upper transparent substrate. The reflective electrode 303 (corresponding to the reflective electrode 7 in FIG. 1) may be arranged with a predetermined gap 303 (corresponding to the opening 7b in FIG. 1). That is, light from the backlight 15 is introduced into the liquid crystal layer 3 through the gap 303.

Here, the first embodiment relates to a simple (passive) matrix type liquid crystal device. For example, in the case of a transflective liquid crystal device of a TFD active matrix driving method to be described later, the embodiment shown in FIG. From the same concept as in the example, as shown in FIG. 5, the lower transparent substrate is opposed to the stripe-shaped transparent electrode 201 (corresponding to the transparent electrode 6 in FIG. 1) formed on the upper transparent substrate. The island-shaped reflective electrode 204 (corresponding to the reflective electrode 7 in FIG. 1) formed for each dot may be arranged with a predetermined gap 205 (corresponding to the opening 7b in FIG. 1). That is, light from the backlight 15 is introduced into the liquid crystal layer 3 through the gap 205. still,
In this case, a scanning line 202 is formed on the lower transparent substrate, and a TFD element 203 is formed corresponding to each dot, and the scanning line 202 and the reflective electrode 204 are connected via the TFD element 203. Have been.

Further, for example, in the case of a transflective liquid crystal device of a TFT active matrix driving system to be described later, it is formed on the upper transparent substrate as shown in FIG. In contrast to the transparent electrode 1401 (corresponding to the transparent electrode 6 in FIG. 1), an island-shaped reflective electrode 1405 formed for each dot on the lower transparent substrate (corresponding to the reflective electrode 7 in FIG. 1). May be arranged with a predetermined gap 1406 (corresponding to the opening 7b in FIG. 1). That is, light from the backlight 15 is introduced into the liquid crystal layer 3 through the gap 1406. In this case, a data line 1402 and a scanning line 1403 are formed on the lower transparent substrate,
Further, a TFT element 1404 is formed corresponding to each dot, and the data line 1402 and the scanning line 1403 are connected to the reflective electrode 1405 via the TFT element 1404.

As shown in FIGS. 1A and 1B again, a polarizing plate 11 is disposed on the outer surface of the front transparent substrate 1, and a retardation plate is provided between the polarizing plate 11 and the transparent electrode 1. 13 are arranged. Further, behind the liquid crystal cell, a retardation plate 14 is disposed behind the transparent substrate 2, and the polarizing plate 12 is disposed behind the retardation plate 14. Behind the polarizing plate 12, a fluorescent tube 15a that emits white light and a fluorescent tube 15a
and a light guide plate 15b having an incident end surface along the line a. The light guide plate 15b is a transparent body such as an acrylic resin plate having a scattering rough surface formed on the entire back surface or a scattering printing layer formed thereon, and receives light from a fluorescent tube 15a as a light source at an end face. , So as to emit substantially uniform light from the upper surface of the drawing. Other backlights include LEDs (light emitting diodes)
Or EL (electroluminescence) can be used.

In the first embodiment, the light-shielding portion is formed between the colored layers of the color filter 5 in order to prevent light from leaking from the region 7a between the reflective electrodes 7 at the time of transmissive display. A black matrix layer 5a is provided substantially corresponding to a plane. The black matrix layer 5a is made of Cr
A layer is deposited or formed of a photosensitive black resin.

Next, the operation of the first embodiment configured as described above will be described.

First, the reflection type display will be described. External light passes through the polarizing plate 11, the phase difference plate 13, and the color filter 5 in FIG. 1, respectively, passes through the liquid crystal layer 3, is reflected by the reflective electrode 7, and is emitted from the polarizing plate 11 again.
At this time, depending on the voltage applied to the liquid crystal layer 3, the polarizing plate 11
(Bright state) and absorption (dark state) and the brightness between them.

Next, the transmission type display will be described. The light from the backlight 15 is converted into predetermined polarized light by the polarizing plate 12 and the phase difference plate 14, introduced into the liquid crystal layer 3 through the opening 7 b of the reflection electrode 7, and after passing through the liquid crystal layer 3, the color filter 5 and the phase difference plate 13 respectively. At this time, transmission (bright state) and absorption (dark state) of the polarizing plate 11 and brightness between them are controlled in accordance with the voltage applied to the liquid crystal layer 3.

Here, as shown in FIG. 7, in the transflective liquid crystal device as in the first embodiment, in general, the characteristic of the reflectance R in the reflective display with respect to the driving voltage and the characteristic in the transmissive display are shown. It has been found through research and experiments by the present inventors that the characteristics of the transmittance T are different from each other. That is, if it is attempted to drive a transflective liquid crystal device of this type with a constant driving voltage for the same image regardless of whether the backlight 15 is turned on or off, if the same image is to be displayed during reflection display, For only one of the transmissive displays,
This means that the slope of the characteristic curve as shown in FIG. 7 cannot be used to the maximum in order to perform high gradation display or to increase the contrast. However, in the present embodiment, the liquid crystal driving voltage applied to the liquid crystal layer 3 via the transparent electrode 6 and the reflective electrode 7 is different between when the backlight 15 is turned on and when the backlight 15 is not turned on for the same image. , The transparent electrode 6 and the reflective electrode 7 are driven. That is, in the present embodiment, at the time of the reflective display in which the backlight 15 is turned off,
When the liquid crystal layer 3 is driven by a driving voltage adapted to the characteristic of the reflectance R as shown in FIG. 7 and the backlight 15 is turned on, the transmission type is adapted to the characteristic of the transmittance T as shown in FIG. The liquid crystal is driven by the applied drive voltage. In particular,
It is very useful to change the level of the voltage applied to the liquid crystal for halftone display between white display and black display between reflective display and transmissive display. The setting of the driving voltage suitable for the characteristics of the reflectance R and the setting of the driving voltage suitable for the characteristics of the transmittance T are respectively performed for the individual liquid crystal devices. Experimental, empirical,
This can be done relatively easily by theoretically obtaining it.
The specific configuration of the driving device for performing such driving will be described in detail as a third embodiment.

According to the above-described embodiment, the display can be switched between the reflective display and the transmissive display without double reflection or blurring of the display. In particular, in either the reflective display or the transmissive display, Also, a high-contrast, high-quality color liquid crystal device can be realized.

According to the first embodiment, the polarizers 11 and 12 enable good display control in both reflective display and transmissive display. Then, the phase difference plate 13 reduces the influence on the color tone such as coloring caused by the wavelength dispersion of light at the time of the reflection type display, and the phase difference plate 14.
Accordingly, it is possible to reduce the influence on the color tone such as coloring caused by the wavelength dispersion of light during transmission display.
Further, with respect to the phase difference plates 13 and 14, it is also possible to arrange a plurality of phase difference plates at respective positions by color compensation of the liquid crystal cell or visual angle compensation.

Further, in the above-described embodiment, the reflective electrode 7 may be configured so as to be not flat but to have, for example, unevenness with a height difference of about 0.8 μm. With such a configuration, the specularity of the reflective electrode 17 can be eliminated by unevenness and can be seen as a scattering surface (white surface), and a display with a wide viewing angle can be performed by scattering due to unevenness. On the other hand, an internal diffusion type in which transparent particles having different refractive indices are dispersed in a transparent substrate such as an acrylic resin between the retardation plate 13 and the transparent substrate 1, or a surface roughened surface of the transparent substrate A transmission type light diffusion plate made of a (matted) surface diffusion type may be provided. With this configuration, reflection of external light due to direct reflection of the reflective electrode 7 can be prevented, and visibility can be improved. Further, on the reflective electrode 7, vapor deposition, sputtering,
A large number of fine pores may be formed by using a photolithography process or the like, whereby the display can be brightened when performing transmissive display and the reflection of external light can be prevented when performing reflective display.

(Second Embodiment) A second embodiment of the liquid crystal device according to the present invention will be described with reference to FIGS. FIG.
FIG. 9A is a schematic vertical sectional view showing the structure of the second embodiment of the present invention, and FIG. 9A is an enlarged plan view showing an example of a reflective electrode according to the second embodiment, and FIG. FIG. 4 is an enlarged plan view showing another example of the reflective electrode. 8, the same components as those of the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. Although this embodiment is basically related to a simple matrix type liquid crystal display device, it can be applied to an active matrix type device, another segment type device, and other liquid crystal devices with the same configuration. It is.

As shown in FIG. 8, in the second embodiment, as compared with the first embodiment, the second electrode on the lower substrate is not a single-layer reflective electrode having an opening, but a half-layer having an opening. The second embodiment is different from the first embodiment in that a transparent electrode is provided on a transmission / reflection plate (that is, the first electrode performs only an electrode function, and a separately provided reflection film performs a semi-transmission / reflection function). The main difference is that the layer is provided on the lower substrate. Other configurations are basically the same as those in the first embodiment.

That is, as shown in FIG. 8, on the transparent substrate 1 side, the alignment film 19 is rubbed in a predetermined direction, and the liquid crystal molecules have a pretilt angle of about 85 degrees in the rubbing direction. . In the case of an active matrix type device including a TFD element and a TFT element, the transparent electrode 6 is formed in a rectangular shape, and is connected to a wiring via the active element.

On the other hand, irregularities having a height of about 0.8 μm are formed on the inner surface of the lower transparent substrate 2 by a photosensitive acrylic resin, and 1.0% by weight of Nd is added on the surface. The resulting Al is sputtered at a thickness of 25 nm to form a semi-transmissive reflection plate 411. A color filter 414 is formed on the semi-transmissive reflection plate 411 via a protective film 412. The color filter 414 has R (red), G
Three colored layers (green) and B (blue) are arranged in a predetermined pattern. A transparent protective film is coated on the surface of the color filter 414, and a plurality of stripe-shaped transparent electrodes 416 are formed on the surface of the protective film using ITO or the like. A plurality of stripe-shaped transparent electrodes 416 formed for each coloring layer of the color filter 414 are arranged so as to intersect the transparent electrodes 6. On the surface of the transparent electrode 416, an alignment film 19 similar to the above is formed. The rubbing treatment is not performed on the alignment film 19. In particular, quarter wave plates are used as the phase difference plates 13 and 14, respectively.

Further, in the second embodiment, the transmission axes P1 and P2 of the polarizing plates 11 and 12 are set in the same direction. The transmission axes P1 and P2 of these polarizing plates 11 and 12
, The phase difference plates (that is, １ ／ wavelength plates) 13 and 1
The directions of the slow axes C1 and C2 of No. 4 are respectively set to directions rotated clockwise by θ = 45 degrees. Further, the direction R1 of the rubbing treatment of the alignment film 9 on the inner surface of the transparent substrate 1 is also in a direction coinciding with the directions of the slow axes C1 and C2 of the phase difference plates (that is, １ ／ wavelength plates) 13 and 14. It has been subjected. The rubbing direction R1 defines the direction in which the liquid crystal layer 3 falls when an electric field is applied. A nematic liquid crystal having a negative dielectric anisotropy is used for the liquid crystal layer 3.

Further, in the second embodiment, in order to prevent light from leaking from the area between the dots during the transmissive display, a black matrix layer which is a light shielding portion formed between the colored layers of the color filter 414 is provided. 413 are provided substantially corresponding to the plane. The black matrix layer 413 is C
An r layer is deposited or formed of a photosensitive black resin.

FIG. 7 shows the characteristics of the reflectance R in the reflective display and the characteristic of the transmittance T in the transmissive display with respect to the driving voltage in the liquid crystal device of the second embodiment configured as described above. The same tendency as in the first embodiment is shown. When the liquid crystal device of the second embodiment is driven, the display state when no electric field is applied is dark (black). By driving in the normally black mode in this manner, light leakage from gaps between the transparent electrodes 416 where liquid crystal is not driven and unnecessary reflected light can be suppressed, so that it is not necessary to form the black matrix layer 413.

Next, the operation of the second embodiment configured as described above will be described.

First, the reflection type display will be described. The external light passes through the polarizing plate 11 and the retardation plate 13 in FIG. 8, respectively, passes through the liquid crystal layer 3, passes through the color filter 414, is reflected by the semi-transmissive reflecting plate 411, and is again turned on.
1 is emitted. At this time, transmission (bright state) and absorption (dark state) of the polarizing plate 11 and brightness between them are controlled in accordance with the voltage applied to the liquid crystal layer 3.

Next, the transmission type display will be described. Light from the backlight 15 is converted into predetermined polarized light (circularly polarized light, elliptically polarized light, or linearly polarized light) by the polarizing plate 12 and the phase difference plate 14, introduced into the liquid crystal layer 3 from the transflective plate 411, and passed through the liquid crystal layer 3. , Through the phase difference plate 13. At this time,
In accordance with the voltage applied to the liquid crystal layer 3, transmission (bright state) and absorption (dark state) of the polarizing plate 11, and intermediate brightness therebetween can be controlled.

Here, as in the first embodiment, also in the second embodiment, when the backlight 15 is turned on and off, the liquid crystal layer 3 is applied to the liquid crystal layer 3 via the transparent electrode 6 and the transparent electrode 416. The transparent electrode 6 and the transparent electrode 416 are driven such that the applied liquid crystal driving voltages are different for the same image. That is, in the present embodiment, at the time of the reflective display in which the backlight 15 is not lit, the liquid crystal layer 3 is driven by the driving voltage suitable for the characteristic of the reflectance R as shown in FIG. At the time of transmissive display, the liquid crystal is driven by a driving voltage suitable for the characteristic of the transmittance T as shown in FIG. The specific configuration of the driving device for performing such driving will be described in detail as a third embodiment.

According to the above-described embodiment, the display can be switched between the reflective display and the transmissive display without double reflection or blurring of the display. In particular, in either the reflective display or the transmissive display, Also, a high-contrast, high-quality color liquid crystal device can be realized.

The transflective plate 411 of the second embodiment
Has a metal layer mainly composed of Al, and its surface is covered with a protective film, on which a color filter layer, a protective film, and a transparent electrode are formed. For this reason, since the Al metal layer does not directly come into contact with the ITO developer or the color filter developer,
The Al metal layer does not dissolve in the developer. Further, the Al metal layer which is easily damaged can be easily handled. 25 nm thick Al doped with 1.0 wt% Nd
Indicates a reflectance of 80% and a transmittance of 10%, and it can be confirmed that the transflective plate 411 functions sufficiently.

Further, the semi-transmissive reflection plate 411 provided with irregularities
Can reflect reflected light at a wide angle, so that a liquid crystal device with a wide viewing angle can be realized.

Here, the transflective plate 41 having an opening is provided.
A specific example of 1 and a transparent electrode 416 provided thereon will be described with reference to FIG.

First, in the first specific example, as shown in FIG. 9A, a stripe-shaped transparent electrode 602 'made of ITO or the like is formed on the upper transparent substrate (corresponding to the transparent electrode 6 in FIG. 8).
8, a reflecting plate 602 ′ (semi-transmissive reflecting plate 41 in FIG.
1, and a transparent electrode 603 ′ (corresponding to the transparent electrode 416 in FIG. 8) having a width W2 (that is, W2> W1), which is a stripe from ITO or the like and is slightly larger than the reflector 602 ′. A plurality is formed. As a result, for each reflection plate 602 ', a portion having a width of W1-W1 functions as an opening. That is, the reflection plate 60 is seen in a plan view as described above.
Light from the backlight 15 can be transmitted through the area where the transparent electrode 416 is not formed and the area where the 2 ′ is not formed, and this area enables transmission type display. On the other hand, when the reflecting plate 602 ′ is formed in a plan view as described above, outside light can be reflected and transmitted through the area where the transparent electrode 416 is formed, and this area can be used to perform reflective display. It becomes possible.

Next, in the second specific example, as shown in FIG. 9B, an island-like reflecting plate 50 made of Al or the like is formed on a lower transparent substrate.
3 (corresponding to the semi-transmissive reflection plate 411 in FIG. 8), and a transparent electrode 504 (corresponding to the transparent electrode 416 in FIG. 8) which is made of ITO or the like and is slightly larger than the reflection plate 503 is formed. ing. As a result, for each of the reflection plates 503, the surrounding area functions as an opening. That is, light from the backlight 15 can be transmitted through the area where the reflective plate 503 is not formed and the transparent electrode 504 is formed in a plan view. Becomes possible. On the other hand, the reflection plate 503 is formed in a plan view and the transparent electrode 5 is formed.
External light can be reflected and transmitted through the area where the area 04 is formed, and this area enables reflective display. This specific example is for a TFD active matrix drive system, and each transparent electrode 504 is
Each scanning line 501 is connected via a TFD element 502. In substantially the same manner as this modification, the transflective plate and the transparent electrode of the liquid crystal device of the TFT active matrix drive system can be formed on the lower transparent substrate.

In the specific example described with reference to FIG. 9, the light incident on the portions other than the pixel electrode and the dot electrode has nothing to do with the display and only lowers the contrast of the transmissive display. It is preferable that the display mode of the (matrix layer) and the liquid crystal layer be normally black, thereby blocking the display mode.

In the specific example of FIG. 9A, the line width (L) of the transparent electrode 601 'made of ITO is 198 μm, and the line width (W) of the reflective layer 602' made of Al on the inner surface of the lower substrate.
If 1) is 46 μm and the line width (W2) of the transparent electrode 603 ′ made of ITO formed thereon is 56 μm,
About 70% of the external light introduced into the liquid crystal layer is reflected, emitted from the backlight, and about 10% of the light introduced into the lower transparent substrate can be transmitted.

Further, since the Al reflective layer of the present embodiment has an ITO transparent electrode formed on its surface, the Al reflective layer can be made hard to be damaged, and two of the Al reflective layer and the ITO transparent electrode are connected to the electrode line. Therefore, the resistance of the electrode line can be reduced.

Third Embodiment Next, a third embodiment of the liquid crystal device including the driving circuits for driving the liquid crystal devices according to the first and second embodiments of the present invention will be described with reference to the block diagram of FIG. I will explain.

In FIG. 10, the liquid crystal device includes a driving device for driving a liquid crystal panel (corresponding to the liquid crystal devices in the first and second embodiments) 103 having a backlight 15 and a light source for driving the backlight 15. Drive device 10
8 and a lighting switching device 107 for switching between lighting and non-lighting of the backlight 15.

The driving device is, in particular, an X driver circuit 110 as an example of the second supply means for driving the data lines wired to the liquid crystal panel 103, and as an example of the second control means for controlling the driving voltage of the X driver circuit 110. Data line drive control circuit 110a, a Y driver circuit 100 as an example of first supply means for driving the scan lines wired to the liquid crystal panel 103, and a first control means for controlling the scan line drive voltage in the Y driver circuit 100. The configuration includes a scanning line drive control circuit 100a as an example. When the image signal Sv and the display control signal Ss are input from an external image signal processing circuit, the data line drive control circuit 110a sends the data line drive control signal S1 to the X driver circuit 110 based on these input signals. Output. In response,
The X driver circuit 110 drives each data line by supplying an image signal to each data line at a predetermined timing. The scanning line drive control circuit 100a outputs the display control signal Ss
Is input from an external image signal processing circuit, a scanning line drive control signal S2 is output to the Y driver circuit 100 based on the input signal. In response, the Y driver circuit 100 drives each scanning line by supplying a scanning signal to each scanning line at a predetermined timing.

Backlight 15 and light source driving device 108
Constitutes an example of a lighting device. Upon receiving the lighting switching signal SL from the lighting switching device 107, the light source driving device 102
Supplies the light source drive voltage VL to the backlight 15 selectively. In response to this, the backlight 15 irradiates the liquid crystal layer in the liquid crystal panel 103 via the transflective layer as described above.

The lighting switching device 107 constitutes an example of lighting switching means, and turns on and off the backlight 15 by operating a manual switch by an operator or detecting an external light level to generate a lighting switching signal SL. Output to the light source driving device 108. That is, in a light place, a lighting switching signal SL for turning off the backlight 15 is output to the light source driving device 108 by manual operation of the operator or automatically upon detection of the external light level, and the backlight 1 is turned on.
No. 5 is not turned on, and reflection type display by external light is performed. On the other hand, in a dark place, the backlight 1 is automatically operated by manual operation by an operator or automatically upon detection of an external light level.
5 is turned on by the light source switching device SL.
08, the light source drive voltage VL is supplied, the backlight 15 is turned on, and transmissive display is performed.

In this embodiment, in particular, the driving device including the X driver circuit 110, the data line driving control circuit 110a, the Y driver circuit 100, and the scanning line driving control circuit 110a as described above is used when the backlight 15 is turned on and off. The lighting switching signal S output from the lighting switching device 107
Based on L, the scanning line and the data line are driven such that the liquid crystal driving voltage applied to the liquid crystal layer via the scanning line and the data line is different for the same image.

More specifically, the data line drive control circuit 1
10a, when a lighting switching signal SL output from the lighting switching device 107 is input, based on the signal level,
When the backlight 15 is not lit, the voltage setting of the image signal supplied to the data line by the X driver circuit 110 with respect to the gradation level (or white and black level) specified by the image signal Sv is, for example, as shown in FIG. Based on the characteristics of the reflectance R, the voltage is switched to a preset voltage setting optimized for the reflective display. Alternatively or additionally, when the lighting switching signal SL output from the lighting switching device 107 is input, the scanning line drive control circuit 100a determines whether or not the backlight 15 is off when the backlight 15 is not lit based on the signal level. The driver circuit 100 switches the voltage setting of the scanning signal supplied to the scanning line to a preset voltage setting optimized for the reflective display based on, for example, the characteristics of the reflectance R as shown in FIG. Further, based on the lighting switching signal SL output from the lighting switching device 107, the data line drive control circuit 110a sets the voltage setting of the image signal supplied to the data line by the X driver circuit 110 when the backlight 15 is turned on. For example, based on the characteristics of the transmittance T as shown in FIG. 7, the voltage is switched to a preset voltage setting optimized for transmission type display. Alternatively or additionally, the scanning line drive control circuit 10
When the backlight 15 is turned on based on the lighting switching signal SL output from the lighting switching device 107, Ya
The voltage setting of the scanning signal supplied to the scanning line by the driver circuit 100 is set based on, for example, the characteristic of the transmittance T as shown in FIG.
The voltage is switched to a preset voltage setting optimized for a transmissive display. The voltage setting in the X driver circuit 110 optimized for the reflective display, the voltage setting in the Y driver circuit 100 optimized for the reflective display, and the voltage setting in the X driver circuit 110 optimized for the transmissive display Since the voltage setting and the voltage setting in the Y driver circuit 100 optimized for the transmissive display are determined by the type of the liquid crystal device, the voltage setting is obtained in advance for each liquid crystal device by experiment, theory, simulation, or the like.
Then, for example, the image signal and / or
Alternatively, the X driver circuit 11 is configured to output a scanning signal.
0, data line drive control circuit 110a, Y driver circuit 1
00 and the scanning line drive control circuit 110 are designed in hardware, and the liquid crystal drive is performed at a voltage setting optimized for reflective display or transmissive display by a simple switching operation in these circuits.

As described above, according to the third embodiment, in the transflective liquid crystal device, the characteristics of the reflectance R in the reflective display and the characteristics of the transmittance T in the transmissive display with respect to the driving voltage are generally obtained. Despite being different from each other, the slope of each of the characteristic curves of the reflectance R and the transmittance T as shown in FIG. High-gradation display can be performed, and contrast can be increased. In particular, it is very useful to change the level of the voltage applied to the liquid crystal for halftone display between white display and black display between the reflective display and the transmissive display.

According to the above-described embodiment, the display can be switched between the reflective display and the transmissive display without double reflection or blurring of the display. In particular, in either the reflective display or the transmissive display, Also, a high-contrast, high-quality color liquid crystal device can be realized.

(Fourth Embodiment) A fourth embodiment of the liquid crystal device according to the present invention will be described with reference to FIGS.
The fourth embodiment is an embodiment of a TFD active matrix liquid crystal device to which the present invention is suitably applied.

First, a configuration near a TFD drive element as an example of a two-terminal nonlinear element used in the present embodiment will be described with reference to FIGS. Here, FIG. 11 is a plan view schematically showing the TFD driving element together with the pixel electrodes and the like, and FIG. 12 is a cross-sectional view taken along the line BB ′ of FIG. In FIG. 12, the scale of each layer and each member is made different so that each layer and each member have a size recognizable in the drawing.

In FIGS. 11 and 12, the TFD drive element 40 is formed on an insulating film 41 formed on the transparent substrate 2 with the insulating film 41 serving as a base. 42, an insulating layer 44 and a second metal film 46, and a TFD structure (Thin Film Diode) or M
It has an IM structure (Metal Insulator Metal structure). Further, the first metal film 42 of the TFD drive element 40 is connected to the scanning line 61 formed on the transparent substrate 2,
The metal film 46 is connected to a pixel electrode 62 made of a conductive reflection film, which is another example of the second electrode. Note that a data line (described later) may be formed on the transparent substrate 2 instead of the scanning line 61, connected to the pixel electrode 62, and the scanning line 61 may be provided on the counter substrate side.

The transparent substrate 2 is made of, for example, an insulating and transparent substrate such as glass or plastic. The insulating film 41 serving as a base is made of, for example, tantalum oxide.
However, the main purpose of the insulating film 41 is to prevent the first metal film 42 from peeling off from the base and not to diffuse impurities from the base into the first metal film 42 by a heat treatment performed after the deposition of the second metal film 46 or the like. Is formed. Therefore, when the transparent substrate 2 is made of a substrate having excellent heat resistance and purity, such as a quartz substrate, the insulating film 41 is omitted when peeling or diffusion of impurities does not pose a problem. be able to. The first metal film 42 is made of a conductive metal thin film, for example, tantalum alone or a tantalum alloy. The insulating film 44 is composed of, for example, an oxide film formed on the surface of the first metal film 42 in a chemical conversion solution by anodic oxidation. The second metal film 46 is made of a conductive metal thin film, for example, chromium alone or a chromium alloy.

In the present embodiment, in particular, the pixel electrode 62 has a rectangular or square slit as in the above-described embodiments.
A light-transmitting region such as a fine opening is provided, or each pixel is formed smaller than the transparent electrode on the opposing substrate so that light can be transmitted through the gap. Further, the pixel electrode 62 may be composed of a single reflective film, or may be composed of a laminate of a reflective layer and a transparent electrode layer.

Further, the pixel electrode 62, the TFD driving element 4
0, a transparent insulating film 29 is provided on the side facing the liquid crystal such as the scanning line 61 (upper surface in the figure), and is formed of an organic thin film such as a polyimide thin film on the predetermined orientation such as a rubbing process. The processed alignment film 19 is provided.

Although several examples of the TFD driving element as the two-terminal type nonlinear element have been described above, a bidirectional element such as a ZnO (zinc oxide) varistor, an MSI (Metal Semi-Insulator) driving element, and an RD (Ring Diode) is used. A two-terminal nonlinear element having a diode characteristic can be applied to the reflection type liquid crystal device of the present embodiment.

Next, the configuration and operation of the TFD active matrix driving type transflective liquid crystal device according to the fourth embodiment, which is provided with the TFD driving elements configured as described above, are shown in FIGS. This will be described with reference to FIG. Here, FIG. 13 is an equivalent circuit diagram showing the liquid crystal element together with a drive circuit, and FIG. 14 is a partially cutaway perspective view schematically showing the liquid crystal element.

In FIG. 13, in the transflective liquid crystal device of the TFD active matrix drive system, a plurality of scanning lines 61 arranged on a transparent substrate 2 are connected to a Y driver circuit 100 constituting an example of a first supply means. The plurality of data lines 60 connected to each other and arranged on
It is connected to an X driver circuit 110 which constitutes an example of the supply means. Note that the Y driver circuit 100 and the X driver circuit 110 may be formed on the transparent substrate 2 or its opposing substrate. In this case, a transflective liquid crystal device with a built-in drive circuit is provided. Alternatively, the Y driver circuit 10
The 0 and X driver circuits 110 are constituted by external ICs independent of the transflective liquid crystal device, and may be connected to the scanning lines 61 and the data lines 60 via predetermined wiring. In this case, the driving circuit ).

In each pixel area of the matrix, the scanning line 60 is connected to one terminal of the TFD drive element 40 (see FIGS. 11 and 12), and the data line 60 is connected to the liquid crystal layer 3 and the pixel electrode 62. Is connected to the other terminal of the TFD drive element 40 via the. Therefore, a scanning signal is supplied to the scanning line 61 corresponding to each pixel region, and the data line 60 is supplied.
Is supplied to the pixel region, T
The FD driving element 40 is turned on, and the TFD driving element 4
0, a driving voltage is applied to the liquid crystal layer 3 between the pixel electrode 62 and the data line 60. In a bright place, the pixel electrode 62 reflects external light to perform a reflective display. In a dark place, light from a backlight is applied to the pixel electrode 62.
The transmission type display is performed by transmitting the light through the openings of.

Referring to FIG. 14, the transflective liquid crystal device includes a transparent substrate 2 and a transparent substrate (opposite substrate) 1 disposed opposite to the transparent substrate. The transparent substrate 1 is made of, for example, a glass substrate. Pixel electrodes 62 are provided in a matrix on the transparent substrate 2, and each pixel electrode 62 is connected to a scanning line 61. The transparent substrate 1 is provided with a plurality of data lines 60 as transparent electrodes that extend in a direction intersecting the scanning lines 61 and are arranged in a strip shape. The data line 60 is made of, for example, a transparent conductive thin film such as an ITO (Indium Tin Oxide) film. Below the data line 60,
For example, an alignment film 9 made of an organic thin film such as a polyimide thin film and subjected to a predetermined alignment process such as a rubbing process is provided. Further, the transparent substrate 1 is provided with a color filter (not shown) made of a color material film arranged in a stripe shape, a mosaic shape, a triangle shape, or the like, depending on its use.

As described above, the TF of the fourth embodiment
According to the transflective liquid crystal device of the D active matrix drive system, a color liquid crystal device capable of switching and displaying between a reflective display and a transmissive display without double reflection or display bleeding can be realized. By switching the setting of the driving voltage for the gradation level between the reflective display and the transmissive display, a high-contrast, high-quality image can be displayed both in the reflective display and in the transmissive display. In particular, the transflective liquid crystal device can be driven in a normally black mode by voltage control in the X and Y driver circuits 110 and 100 which constitute an example of the driving means.

(Fifth Embodiment) Next, the fifth embodiment shown in FIG.
Including a driver circuit 110 and an X driver circuit 110,
The configuration and operation of one embodiment of a driving device for driving the above-described transflective liquid crystal device of the TFD active matrix driving method will be described with reference to FIGS. FIG. 15 is a block diagram showing a specific configuration of the driving device, FIG. 16 is a waveform diagram of the first GCP signal and the second GCP signal, and FIG. 17 is a diagram showing one data line in the X driver circuit. FIG. 18 is a block diagram of a part to be driven, and FIG. 18 is a timing chart showing waveforms and time relationships of various signals in the driving device. FIG. 19 is a characteristic diagram showing a change in the ON width of the signal pulse applied to one pixel during the 1H period for each gradation level.

As shown in FIG. 15, the driving device applies an applied voltage having an effective value of a magnitude corresponding to the gradation level indicated by the gradation data (display data) to the liquid crystal element (the main body of the liquid crystal device excluding the driving circuit). And a Y driver circuit 110 and an X driver circuit 110, which are examples of first and second supply means for supplying the first and second supply units, respectively. The driving device switches the setting of each pulse width of the data signal for each gradation level in the X driver circuit 110, thereby setting each magnitude of the effective value of the applied voltage for each gradation level to the light source lamp 212a.
A driver control circuit 310 which constitutes an example of a second control means for switching to a setting for reflection type display in accordance with non-lighting of the device and to a setting for transmission type display in accordance with lighting of the light source lamp 212a, and a Y driver circuit 100 and X
It further includes a control power supply circuit 320 for supplying predetermined control voltages of a high potential, a low potential, and a reference potential to the driver circuit 110, and a lighting control circuit 330 for controlling lighting and non-lighting (light-out) of the light source lamp 212b.

The driver control circuit 310 is a first GCP (gray scale control pulse) signal which is the basis of pulse width modulation when the X driver circuit 110 generates a data signal having a pulse width corresponding to the gradation level as described later. And the first G for generating the second GCP signal, respectively.
A CP generation circuit 311 and a second GCP generation circuit 312,
When RGB gradation data is input, the data control circuit 313 converts the data into a data signal of a predetermined format and outputs the data signal to the X driver circuit 110, various control signals such as an X clock signal, a vertical synchronization signal, a horizontal synchronization signal, and the like. A timing signal or the like is input, and the first and second GCP generation circuits 3
LCD for generating LCD drive signal for controlling generation timing of first and second GCP signals in 11 and 312
And a drive signal generation circuit 314.

The first GCP generation circuit 311 is a first GCP circuit composed of a plurality of pulses arranged in correspondence with the gradation level, which is a reference for setting the pulse width for the above-mentioned reflective display.
Generate a CP signal.

The second GCP generation circuit 312 is a second GCP circuit composed of a plurality of pulses arranged in correspondence with gradation steps, which is a reference for setting the pulse width for the transmission type display.
Generate a CP signal.

As shown in FIG. 16, the first and second GCP
The signals have mutually different pulse arrangements, and the first G
The pulse width of the same grayscale data differs between the data signal supplied from the X driver circuit 110 based on the CP signal and the data signal supplied from the X driver circuit 110 based on the second GCP signal. First and second GCP
When the signal is gradation data of N gradations, the data for displaying the gradation level (N-1) from the pulse corresponding to the pulse width of the data signal for displaying the gradation level (1) respectively. A total of N-2 until the pulse corresponding to the pulse width of the signal
The pulses are arranged so that the pulse intervals correspond to the steps of the gradation level.

The first and second GCP generation circuits 3
Reference numerals 11 and 312 each include, for example, a plurality of comparison circuits and an OR circuit for calculating a logical sum of the comparison results. These comparison circuits previously determine the voltage value of the LCD drive signal for each gradation. A comparison is made with a plurality of voltage values set for reflective display or transmissive display based on the change width of the pulse width with respect to the level increment. By calculating the logical sum of the comparison results of these comparison circuits,
As the calculation output, the first and second pulse trains as shown in FIG. 16 are formed of a train of N-2 pulses per one selection period having different intervals corresponding to the change width of the pulse width corresponding to the step of each gradation level. It is configured to generate a 2GCP signal.

Referring again to FIG. 15, the driver control circuit 310 further includes a pulse signal switch 315 for selectively supplying one of the first and second GCP signals to the X driver circuit 110. The pulse signal switch 315 is connected to the lighting control circuit 330
The first GCP signal is supplied in synchronization with the non-lighting (light-out) control using the lighting switch 331 by the lighting control circuit 330, and the second GCP signal is supplied in synchronization with the lighting control using the lighting switch 331 by the lighting control circuit 330. Thus, the pulse signal switch 315 is switched. The lighting and non-lighting control by the lighting control circuit 330 is performed, for example, by operating a manual switch by a user or detecting the intensity of external light.
It is performed by an automatic switch operation based on the detection result. Then, the pulse signal switch 315 is switched in synchronization with the lighting and non-lighting control. Therefore, the setting for the reflective display and the setting for the transmissive display can be switched reliably and without delay depending on whether the light source lamp 212a is turned off (turned off) or turned on.

Note that such a pulse signal switch 315
May be configured to be performed based on the lighting control signal Smode sent from the lighting control circuit 330 to the lighting switch 331 as shown in FIG.
It may be configured to perform based on a detection signal from a detector that detects whether the light source lamp 212a is turned on or off.

In FIG. 15, control power supply circuit 320
Are a high-potential voltage (VHX) and a low-potential voltage (VL) used by the X driver circuit 110 for generating a data signal.
X), an X-side power supply circuit 321 for supplying a control voltage such as a reference potential voltage (VCX), and a Y driver circuit 100
Is a high-potential voltage (VH
Y), low potential voltage (VLY), reference potential voltage (VC
Y) power supply circuit 322 for supplying a control voltage such as Y)
And is provided.

As shown in FIG. 17, the X driver circuit 11
0, a driver control circuit 31 is provided in the X driver circuit portion 110a for supplying a data signal to one data line.
For example, from the data control circuit 313 of FIG.
Display data in the form of a digital signal consisting of a predetermined number of bits such as 6 bits indicating one level of 3) is input for each pixel. Also, a horizontal synchronization signal HSYNC of display data, a reference clock XCK for the X driver circuit 110, a RES signal which is a pulse signal generated every one selection period, and voltage levels at the start and end of each selection period, respectively. And an FR signal which is a binary signal that is inverted. The control power supply circuit 330 (see FIG. 15) supplies voltages VHX and VC as power sources for generating data signals.
X and VLX are provided. Further, in the present embodiment, in particular, the GCP signal (first or second GCP signal) is supplied from the pulse signal switch 315 of the driver control circuit 310.
Is supplied.

In FIG. 17, X driver circuit portion 11
0a includes a shift register 401, a latch circuit 402, a gray scale control circuit 403, a GCP decoder circuit 404, an FR decoder circuit 405, a level shifter circuit 406, and an LCD driver 408.

When the display data is input, the X driver circuit portion 110a sequentially holds the display data in the shift register 401 every predetermined number of bits. The latch circuit 402 has a latch unit corresponding to a plurality of data lines in a one-to-one correspondence, and sequentially transfers display data to the shift register 401 to hold all display data for one horizontal line. At this point, the data is again latched by the latch circuit 402.

Here, the GCP decoder 404 is controlled by the gray scale control circuit 403 in accordance with the GCP signal composed of a predetermined number of pulse trains per one selection period, and outputs a predetermined number of bits of display data in the latch circuit 402. A signal having a pulse width corresponding to the gradation level indicated by (digital value) is generated.

The FR decoder 405 uses the FR signal, which is a binary signal whose voltage level changes every selection period, to generate a GC signal.
A data signal having a waveform in which the voltage polarity of the signal output of the P decoder circuit 404 is inverted for each selection period is output. More specifically, an on / off signal for each transistor constituting the LCD driver 408 is generated for each selection period according to the MSB of the latched display data (digital value). The reason for inverting the voltage level of the data signal corresponding to ON every selection period (1H period) is to drive the liquid crystal in AC, and the ON / OFF voltage of the scanning signal is also inverted every 1H period. You.

The LCD driver 40 thus generated
The on / off signal of each transistor in 8 is shifted by the level shifter circuit 406 to a voltage level corresponding to each data line. When the on / off signal whose voltage level is shifted is input to each gate, each transistor of the LCD driver circuit 408 is turned on / off, and the voltage value of each pulse is connected to each source or drain. The voltage value is defined by a combination of the plurality of voltages VHX, VCX, and VLX.

The digital signal for one horizontal line is held by the X driver circuit 110 (see FIG. 15) including a plurality of the X driver circuit portions 110a configured as described above. Will be supplied.

The above operation will be further described with reference to the timing chart of FIG.

As shown in FIG. 18, the X driver circuit 11
0, the RES signal is input for each selection period, and in parallel with this, for example, 62 (= N−2: 6) in one selection period
A GCP signal composed of a pulse train of four gradations) is input. Further, for example, display data (digital signal) indicating gradation levels 2, 5, and 0 for a specific pixel is input to the field. Entered in units. Then, based on the GCP signal, the level of the data signal is turned on by the GCP decoder 404 at the timing of the second or fifth pulse. Then, based on the FR signal, the polarity of the ON voltage or the OFF voltage of the data signal is inverted by the FR decoder 405 for each selection period, and a data signal having a predetermined peak value is output.

At this time, the ratio of the time at which the data signal takes two values in one selection period (1H period) and the transmittance of the liquid crystal panel do not generally have a linear relationship. For example, in the case of 64 gradations, each gradation level 0 (for example, black), 1, 2,.
63 (for example, white) and the ON width have a relationship shown in the graph of FIG. 19 due to the characteristics of the liquid crystal and the characteristics of the liquid crystal panel. Therefore, in the gray scale display in the present embodiment, the ON width of the data signal is changed according to the gray scale level indicated by the input data based on such a relationship.
That is, since the change rate of the ON width decreases as the gradation level approaches the gradation level 0 side to the gradation level 63 side, a smaller difference in the ON width is controlled. As shown in the second row, the number of “grayscale levels−2” (for example, in the case of 64 grayscale levels) so that the intervals differ according to the difference in the ON width of the data signal corresponding to the grayscale level difference A GCP signal composed of a train of 62 pulses is generated. That is, under the relationship as shown in FIG.
The GCP generation circuits 311 and 312 respectively generate first and second GCP signals composed of a train of 62 pulses whose interval gradually narrows as the gradation level increases.

On the basis of the GCP signal (first or second GCP signal) having such a property, for example, in FIG.
The data signal is turned on (for example, at a high voltage level) only during the period from the second pulse in the CP signal to the end of the 1H period. Next, for the gradation level 5, the data signal is turned on (for example, at a low voltage level) only during the period from the fifth pulse in the GCP signal to the end of the 1H period in the corresponding 1H period. Next, the gradation level 0
In contrast, the data signal is turned off (for example, at a high voltage level) until the end of the corresponding 1H period.

Then, as shown at the bottom of FIG.
An applied signal (= scanning signal−data) applied to one pixel electrode (that is, a pixel electrode connected between one data line to which the display data shown is supplied and a scanning line (Nth row)) Signal) exceeds the threshold value of the TFD drive element for a period corresponding to the ON width of the corresponding data signal, and turns the TFD drive element on (low resistance state). As a result, an effective voltage corresponding to the ON width of the data signal is applied to the liquid crystal layer portion sandwiched between the pixel electrode and the data line or the scanning line.

As described above, the ON width of the data signal determines the transmittance of each pixel of the liquid crystal panel, and the display corresponding to the display data is performed on the entire liquid crystal panel.

As a result, with the driving apparatus of the present embodiment, the reflection type display can be performed when the light source lamp 212a is not lit, and the transmission type display can be performed when the light source lamp 212a is lit.

In the present embodiment, in particular, the pulse signal switch 315 (see FIG. 15) of the driver control circuit 310 sets the magnitude of the effective value of the applied voltage for each gradation level in the X driver circuit 110. The setting is switched to the setting for the reflection type display according to the non-lighting of the light source lamp 212a, or is switched to the setting for the transmission type display according to the lighting of the light source lamp 212a.

Accordingly, the relationship between the gradation level and the reflectance during the reflective display is determined by the relationship adapted to the characteristic of the transmittance T with respect to the drive voltage shown in FIG. 7, that is, the slope of the characteristic curve of the transmittance T is changed. Setting of each pulse width of the data signal for each gradation level so as to maximize the relationship (specifically, setting of the interval of each pulse for each gradation level in the first GCP signal shown in FIG. 16) Is performed, the contrast in the transmissive display can be efficiently increased. At the same time, each pulse of the data signal for each gradation level is set so as to have a relationship suitable for the characteristics of the reflectance R with respect to the drive voltage shown in FIG. 7, that is, a relationship that maximizes the slope of the characteristic curve of the reflectance R. Setting the width (specifically,
By performing the setting of the interval of each pulse for each gradation level in the first GCP signal shown in FIG. 16), the contrast in the reflective display can be efficiently increased.

As described above, according to the liquid crystal device of the fifth embodiment, double reflection due to parallax and blurring of display do not occur, and high contrast and high quality can be obtained during both reflective display and transmissive display. Can be displayed.

In this embodiment, the switching between the reflective display mode and the transmissive display mode can be performed quickly and reliably by a relatively simple switching operation by the pulse signal switch 315, which is practically convenient. .

(Sixth Embodiment) Next, the sixth embodiment shown in FIG.
Including a driver circuit 110 and an X driver circuit 110,
The configuration and operation of another embodiment of the driving device for driving the above-mentioned TFD active matrix driving type transflective liquid crystal device will be described with reference to FIGS. FIG. 20 is a block diagram showing a specific configuration of the driving device, FIG. 21 is a conceptual diagram showing waveforms of two types of scanning signals, and FIG. 21 is a peak value (DC voltage) of the scanning signals. FIG. 4 is a characteristic diagram of transmittance (T) with respect to FIG.
In FIG. 20, the same components as those in the fifth embodiment shown in FIG. 15 are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 20, the driving device includes a driver having a single GCP generation circuit 311 ′ instead of the first and second GCP generation circuits 311 and 312 and the pulse signal switch 315 in the fifth embodiment. The control circuit 310 'is provided. The drive device includes first and second control power supply circuits instead of the control power supply circuit 320 in the fifth embodiment.
Y-side power supply circuits 323 and 324 and first and second Y
The control power supply circuit 320 ′ includes a control voltage switch 325 that selectively supplies the control voltage from the side power supply circuits 323 and 324 to the Y driver circuit 100. The control voltage switch 325 performs a switching operation based on the lighting control signal Smode supplied from the lighting control circuit 330. Other configurations are the same as those of the fifth embodiment shown in FIG.

Here, in particular, the control power supply circuit 320 '
Constitutes an example of a second control unit. The first Y-side power supply circuit 323 includes a high-potential voltage (VHY1) serving as a reference for setting a peak value of a scanning signal for reflection display, and a low-potential The voltage (VLY1) and the reference potential voltage (VCY1) are supplied as a set of first control voltages. On the other hand, the second Y-side power supply circuit 324, as an example of the second control voltage, has a high-potential voltage (VHY2) and a low-potential voltage (VLY2) as a reference for setting the peak value of the scanning signal for transmissive display. , The reference potential voltage (VCY2) is supplied as a set of second control voltages. The control voltage switch 325 is connected to the light source lamp 2
The first control voltage is selectively supplied to the Y driver circuit 100 in accordance with the non-lighting of the light source lamp 12a, and the second control voltage is selectively supplied to the Y driver circuit 100 in accordance with the lighting of the light source lamp 212a. ing.

Therefore, in the sixth embodiment, the X driver circuit 110 supplies a data signal having a pulse width corresponding to the gradation level to the data line. In parallel with this, a scanning signal having a predetermined width and a peak value corresponding to the first or second control voltage is supplied to the scanning line by the Y driver circuit 100.

FIG. 21 is a waveform diagram showing an example of the two types of scanning signals generated in this manner.

In FIG. 21, a scanning signal set for reflective display generated based on the first control voltage (in FIG.
The peak value of the latter is higher by ΔV than the peak value of the former in the scanning signal (right side in the figure) set for the transmissive display generated based on the second control voltage. Therefore, in the normally white mode, the brightness of the display becomes darker when driven by the scanning signal in the transmissive display because the voltage value of the applied voltage is larger by ΔV. That is,
Since the voltage value of the applied voltage is smaller by ΔV when driven by the scanning signal at the time of the reflection type display, the display brightness becomes brighter.

Therefore, the relationship between the gradation level and the reflectance during the reflective display is determined by the relationship adapted to the characteristic of the transmittance T with respect to the driving voltage shown in FIG. 7, that is, the slope of the characteristic curve of the transmittance T is changed. The setting of the second control voltage for each gradation level so as to make the maximum use relationship (specifically,
By setting the values of the voltages VHY2, VLY2, and VCH2), the contrast in the transmissive display can be efficiently increased. At the same time, the first control voltage for each gradation level is set so as to have a relationship suitable for the characteristic of the reflectance R with respect to the drive voltage shown in FIG. 7, that is, a relationship that makes full use of the slope of the characteristic curve of the reflectance R. (Specifically, the voltage VH
Y1, VLY1, and VCH1 values) can effectively increase the contrast during reflective display.

As described above, according to the liquid crystal device of the sixth embodiment, no double reflection due to parallax or display bleeding occurs, and high contrast and high quality can be obtained in both reflective display and transmissive display. Can be displayed. The voltages VHY1 and VL constituting the specific first and second control voltages
The values of Y1, VCY1, VHY2, VLY2, and VCY2 are experimentally, theoretically,
It is determined by simulation or the like. In the case of employing a driving method in which the applied voltage is inverted every selection period, the high-potential voltage VHY1 (VHY2), the low-potential voltage VLY1 (VLY2), and the reference potential voltage VCY1 (VC
Y2) is necessary, but as long as the peak value can be switched as shown in FIG. 21, one or two of the three voltages are between the first control voltage and the second control voltage. The same potential may be used. That is, the voltage actually switched by the switch is not three, but may be two or one. Also,
If the above-described inversion drive is not performed, the first and second control voltages may each be a pair of voltages.

In this embodiment, in particular, the switching operation between the reflective display mode and the transmissive display mode can be performed quickly and reliably by a relatively simple switching operation by the control voltage switch 325, which is practically convenient. .

In the fifth and sixth embodiments described above, based on the so-called “four-value driving method”, the amount of electricity defined by the pulse width and peak value of the data signal is modulated in correspondence with the gradation level. According to the present invention, such gradation control may be performed based on the charge / discharge driving method disclosed in, for example, Japanese Patent Laid-Open No. 2-125225. It is possible.

(Seventh Embodiment) A seventh embodiment of the liquid crystal device according to the present invention will be described with reference to FIGS.
The seventh embodiment is an embodiment of a TFT active matrix liquid crystal device to which the present invention is suitably applied. FIG.
Is an equivalent circuit of various elements, wirings, etc. in a plurality of pixels formed in a matrix forming an image display area of the liquid crystal device. FIG. 23 is a transparent circuit in which data lines, scanning lines, pixel electrodes, etc. are formed. FIG. 24 is a plan view of a plurality of pixel groups adjacent to each other on the substrate, and FIG. 24 is a cross-sectional view taken along the line CC ′ of FIG.
In FIG. 24, the scale of each layer and each member is different for each layer or each member in order to make the size recognizable in the drawing.

In FIG. 22, in the transflective liquid crystal device of the TFT active matrix system of the seventh embodiment,
A plurality of TFTs 130 for controlling the pixel electrode 62, which is another example of the second electrode arranged in a matrix, are formed in a matrix. A data line 135 to which an image signal is supplied is electrically connected to the source of the TFT 130. It is connected to the. The image signals S1, S2,
, Sn may be supplied line-sequentially in this order.
A plurality of data lines 135 adjacent to each other may be supplied for each group. Also, the TFT 130
The scanning lines 131 are electrically connected to the gates, and the scanning signals G1, G2,..., Gm are applied to the scanning lines 131 in a pulsed manner in this order at a predetermined timing. I have. The pixel electrode 62 is electrically connected to the drain of the TFT 130. By closing the switch of the TFT 130, which is a switching element, for a certain period, the image signals S1, S2,. Write at a predetermined timing.
The image signals S1, S2,..., Sn of a predetermined level written to the liquid crystal via the pixel electrodes 62 are held for a certain period between the counter electrodes (described later) formed on the counter substrate (described later). . Here, in order to prevent the held image signal from leaking, a storage capacitor 170 is added in parallel with a liquid crystal capacitor formed between the pixel electrode 62 and the counter electrode.

In FIG. 23, on a transparent substrate 2 as a TFT array substrate, pixel electrodes 62 (contours 62a are shown by dotted lines in the figure) formed of a reflective film in a matrix are provided. The data line 135, the scanning line 131, and the capacitance line 13 are respectively provided along the vertical and horizontal boundaries of the electrode 62.
2 are provided. The data line 135 is connected to the semiconductor layer 8 made of a polysilicon film or the like via the contact hole 85.
1a is electrically connected to the source region. The pixel electrode 62 is connected to the semiconductor layer 81 via the contact hole 88.
a is electrically connected to the drain region. The capacitance line 132 is opposed to the first storage capacitance electrode extending from the drain region of the semiconductor layer 1a via the insulating film, and forms the storage capacitance 170. The semiconductor layer 81
The scanning line 131 is disposed so as to face the channel region 81a 'indicated by a hatched region in FIG. 3A, which rises to the right in the figure, and the scanning line 131 functions as a gate electrode. As described above, each of the intersections of the scanning line 131 and the data line 135 is provided with a TFT 130 in which the scanning line 131 is opposed to the channel region 81a 'as a gate electrode.

As shown in FIG. 24, the liquid crystal device comprises a transparent substrate 2 and a transparent substrate (opposite substrate) 1 arranged opposite thereto.
And Each of these transparent substrates 1 and 2 is made of, for example, an insulating and transparent substrate such as quartz, glass, or plastic.

In this embodiment, in particular, the pixel electrode 62 has a rectangular or square slit as in the above-described embodiments.
A light-transmitting region such as a fine opening is provided, or each pixel is formed smaller than the transparent electrode on the opposing substrate so that light can be transmitted through the gap. Further, the pixel electrode 62 may be composed of a single reflective film, or may be composed of a laminate of a reflective layer and a transparent electrode layer.

Further, a transparent insulating film 29 is provided on the side (upper surface in the figure) of the pixel electrode 62, the TFT 130 and the like facing the liquid crystal, on which an organic thin film such as a polyimide thin film is formed. There is provided an alignment film 19 that has been subjected to a predetermined alignment process such as.

On the other hand, a counter electrode 121 as another example of a transparent electrode is provided on almost the entire surface of the transparent substrate 1, and a non-opening region of each pixel is provided with a black mask or a black matrix called a black matrix. Two light-shielding films 122 are provided. Below the counter electrode 121, an alignment film 9 made of an organic thin film such as a polyimide thin film and subjected to a predetermined alignment process such as a rubbing process is provided. Furthermore,
The transparent substrate 1 is provided with a color filter (not shown) made of color material films arranged in a stripe shape, a mosaic shape, a triangle shape, or the like, depending on the application.

The transparent substrate 2 is provided with a pixel switching TFT 130 for controlling the switching of each pixel electrode 62 at a position adjacent to each pixel electrode 62.

[0139] Between the pair of transparent substrates 1 and 2 arranged so that the pixel electrode 62 and the opposing electrode 121 face each other, a sealing material is used as in the case of the first embodiment. Liquid crystal is sealed in the enclosed space, and the liquid crystal layer 3
Is formed.

Further, a plurality of pixel switching TFTs 3
Below 0, a first interlayer insulating film 112 is provided.
The first interlayer insulating film 112 functions as a base film for the pixel switching TFT 30 by being formed on the entire surface of the transparent substrate 2. The first interlayer insulating film 112 is made of, for example, NSG (non-doped silicate glass), PSG
(Phosphorus silicate glass), high insulating glass such as BSG (boron silicate glass), BPSG (boron phosphor silicate glass), or a silicon oxide film, a silicon nitride film, or the like.

In FIG. 24, the pixel switching TF
T130 is connected to the data line 1 via the contact hole 85.
It comprises a source region connected to 35, a channel region 81 a ′ opposed to the scanning line 131 via a gate insulating film, and a drain region connected to the pixel electrode 62 via a contact hole 88. Data line 13
Reference numeral 1 denotes a light-shielding and conductive thin film such as a low-resistance metal film such as Al or an alloy film such as metal silicide. In addition, contact holes 85 and 88
A second interlayer insulating film 114 is formed,
Further, a third interlayer insulating film 117 having a contact hole 88 formed thereon is formed thereon. These second and third interlayer insulating films 114 and 117 also have NSG, PSG, BSG, B
It is made of highly insulating glass such as PSG, or a silicon oxide film, a silicon nitride film, or the like.

The pixel switching TFT 130 is an LD
The TFT may have any structure such as a D structure, an offset structure, and a self-aligned structure. Further, in addition to the single gate structure, the TFT 130 may be configured with a dual gate or a triple gate or more.

The TF of the seventh embodiment configured as described above
In the transflective liquid crystal device of the T active matrix drive system, the scanning lines 131 are driven by the X driver circuit and the data lines 135 are driven by the Y driver circuit. At this time, the counter electrode 121 and the pixel electrode 6 are arranged such that the liquid crystal driving voltage applied to the liquid crystal layer 3 via the counter electrode 121 and the pixel electrode 62 (see FIG. 24) is different for the same image.
2 is driven. That is, by switching the voltage setting of at least one of the image signal supplied to the data line 135 and the scanning signal supplied to the scanning line 131 in the driving circuit in accordance with the lighting or non-lighting of the illumination device, the reflection type display is performed. While driving the liquid crystal layer 3 with a drive voltage suitable for the reflectance characteristic with respect to the drive voltage in the reflective display,
At the time of transmissive display, the liquid crystal layer 3 can be driven by a drive voltage suitable for a reflectance characteristic with respect to a drive voltage in the transmissive display. In this case, not only can the contrast between the reflective display and the transmissive display be increased, but also the gamma correction can be performed simultaneously.

As described above, the TF of the seventh embodiment is used.
According to the transflective liquid crystal device of the T active matrix drive system, between the pixel electrode 62 and the counter electrode 121,
By sequentially applying an electric field to the liquid crystal portion of each pixel electrode 62, the alignment state of each liquid crystal portion can be controlled, and in a bright place, the pixel electrode 62 reflects external light to perform a reflective display, and in a dark place, The transmission type display is performed by transmitting the light source light from the backlight through the opening of the pixel electrode 62. As a result, it is possible to realize a color liquid crystal device that can switch and display between a reflective display and a transmissive display without double reflection or display bleeding, and achieve high contrast and high quality both in the reflective display and the transmissive display. Can be displayed.

In particular, each pixel electrode 6 is connected via the TFT 130.
Since power is supplied to the pixel 2, crosstalk between the pixel electrodes 62 can be reduced, and higher-quality image display can be performed.

It should be noted that the driving may be performed by a horizontal electric field parallel to the substrate between the pixel electrodes 62 on the transparent substrate 2 without providing the counter electrode on the transparent substrate 1.

Here, the coloring layer of the color filter 5 used in the first to seventh embodiments described above will be described with reference to FIG. FIG. 25 is a characteristic diagram showing the transmittance of each colored layer of the color filter 5. In each of the embodiments, when performing the reflective display, the incident light once passes through one of the coloring layers of the color filter 5 and then passes through the liquid crystal layer 3 and is reflected by the reflection electrode 7 or the like. Released after transmission. Therefore, unlike a normal transmissive liquid crystal device, the light passes through the color filter twice, and the display becomes dark with the normal color filter,
The contrast decreases. Therefore, in each embodiment, as shown in FIG. 25, the minimum transmittance 61 in the visible region of each of the R, G, and B colored layers of the color filter 5 is 25 to 50.
%. Lightening of the colored layer is achieved by reducing the thickness of the colored layer or reducing the concentration of the pigment or dye mixed in the colored layer. Thus, it is possible to configure so as not to lower the brightness of the display when performing the reflective display.

The lightening of the color filter 5 results in the lightening of the display because the light is transmitted through the color filter 5 only once when performing transmissive display. However, in each embodiment, the light of the backlight is reflected by the reflective electrode. Is often blocked, which is rather convenient in securing the brightness of the display.

(Eighth Embodiment) An eighth embodiment of the present invention will be described with reference to FIG. The eighth embodiment is an embodiment of an electronic apparatus including any one of the first to seventh embodiments described above. That is, the eighth embodiment is applicable to various electronic devices that suitably use the liquid crystal device described in the above first to seventh embodiments as a display unit of a portable device that requires low power consumption in various environments. Get involved. FIG. 26 shows three examples of the electronic device of the present invention.

FIG. 26A shows a portable telephone, and the main body 7
A display unit 72 is provided in an upper part of the front surface of the device 1. Mobile phones are used in all environments, both indoors and outdoors. Especially, it is often used in cars, but the inside of cars at night is very dark. Therefore, it is desirable that the display device used in the mobile phone is a transflective liquid crystal device capable of performing transmissive display using auxiliary light as needed, mainly reflective display with low power consumption. When the liquid crystal device described in the first to seventh embodiments is used as the display unit 72 of the mobile phone, a mobile phone that is brighter and has a higher contrast ratio than the conventional one in both the reflective display and the transmissive display can be obtained.

FIG. 26B shows a watch, in which a display 74 is provided at the center 73 of the main body. An important aspect in watch applications is luxury. When the liquid crystal described in the first to fourteenth embodiments of the present invention is used as the display portion 74 of the watch, not only is the display portion 74 bright and high in contrast, but also the coloring is small because the characteristic change due to the wavelength of light is small. Therefore, a very high-quality color display can be obtained as compared with the conventional watch.

FIG. 26C shows a portable information device, in which a display section 76 is provided on the upper side of a main body 75 and an input section 77 is provided on the lower side. In addition, touch keys are often provided on the front surface of the display unit 76. Normal touch keys have a lot of surface reflections, making it difficult to see the display. Therefore, conventionally, a transmissive liquid crystal device is often used as a display even though it is a portable type. However, since the transmissive liquid crystal device always uses a backlight, the power consumption is large and the battery life is short. Even in such a case, if the liquid crystal device of the above-described first to seventh embodiments is used as the display unit 76 of the portable information device, the display is bright and vivid regardless of the reflective type, the transflective type, or the transmissive type. Information equipment can be obtained.

The liquid crystal device of the present invention is not limited to the above-described embodiments, but can be appropriately modified without departing from the spirit or spirit of the invention which can be read from the claims and the entire specification. A liquid crystal device with a change is also included in the technical scope of the present invention.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view (FIG. 1 (a)) and a schematic plan view (FIG. 1 (b)) showing a schematic structure of a first embodiment of a liquid crystal device according to the present invention.

FIG. 2 is a plan view showing a specific example of an opening in the first embodiment.

FIG. 3 is a plan view showing another specific example of the opening in the first embodiment.

FIG. 4 is a plan view showing another specific example of the opening in the first embodiment.

FIG. 5 is a plan view showing another specific example of the opening in the first embodiment.

FIG. 6 is a plan view showing another specific example of the opening in the first embodiment.

FIG. 7 is a characteristic diagram showing a characteristic of a reflectance R in a reflective display and a characteristic of a transmittance T in a transmissive display with respect to a drive voltage in the liquid crystal device of the first embodiment.

FIG. 8 is a schematic longitudinal sectional view showing a schematic structure of a liquid crystal device according to a second embodiment of the present invention.

FIG. 9 is a schematic vertical plan view illustrating a schematic structure of a pixel electrode in a second embodiment.

FIG. 10 is a block diagram of a liquid crystal device in a third embodiment of the liquid crystal device according to the present invention.

FIG. 11 shows a TF according to a fourth embodiment of the liquid crystal device of the present invention.
FIG. 3 is a plan view schematically illustrating a D driving element together with a pixel electrode and the like.

FIG. 12 is a sectional view taken along line B-B 'of FIG.

FIG. 13 is an equivalent circuit diagram showing a liquid crystal element according to a fourth embodiment together with a drive circuit.

FIG. 14 is a partially broken perspective view schematically showing a liquid crystal element according to a fourth embodiment.

FIG. 15 is a block diagram of a liquid crystal panel according to a fifth embodiment of the liquid crystal device of the present invention.

FIG. 16 is a waveform chart of first and second GCP signals generated in the fifth embodiment.

FIG. 17 is a block diagram of a part of an X driver circuit included in the driving device provided in the fifth embodiment.

FIG. 18 is a timing chart showing the operation of the driving device provided in the fifth embodiment.

FIG. 19 is a characteristic diagram illustrating a change in an ON width of a data signal driving pulse during a 1H period with respect to a grayscale level in the fifth embodiment.

FIG. 20 is a block diagram of a liquid crystal device including a liquid crystal panel and a driving device according to a sixth embodiment of the present invention.

FIG. 21 is a waveform diagram of two types of scanning signals generated in the sixth embodiment.

FIG. 22 is an equivalent circuit of various elements, wiring, and the like in a plurality of pixels formed in a matrix and constituting an image display area of a liquid crystal device according to a seventh embodiment of the present invention.

FIG. 23 is a plan view of a plurality of pixel groups adjacent to each other on a transparent substrate on which data lines, scanning lines, pixel electrodes, and the like are formed according to a seventh embodiment.

24 is a sectional view taken along the line C-C 'of FIG.

FIG. 25 is a graph showing the light transmittance of each color layer of the color filter in the first to seventh embodiments.

FIG. 26 is a schematic perspective view of various electronic devices according to an eighth embodiment of the invention.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Seki ▲ Takumi 3-3-5 Yamato, Suwa City, Nagano Prefecture Inside Seiko Epson Corporation (72) Inventor Osamu Okumura 3-3-5 Yamato Suwa City, Nagano Prefecture No. Seiko Epson Corporation

Claims (10)

[Claims] 1. A pair of transparent first and second substrates, a liquid crystal layer sandwiched between the first and second substrates, and a transparent liquid crystal layer formed on a surface of the first substrate on the liquid crystal layer side. A first electrode, a second electrode formed of a transflective layer formed on a surface of the second substrate on the side of the liquid crystal layer, and a lighting device disposed on a side of the second substrate opposite to the liquid crystal layer; The first and second electrodes are arranged such that a liquid crystal driving voltage applied to the liquid crystal layer via the first and second electrodes is different for the same image when the lighting device is turned on and when the lighting device is not turned on. A liquid crystal device comprising: driving means for driving. 2. A pair of transparent first and second substrates, a liquid crystal layer sandwiched between the first and second substrates, and a transparent liquid crystal layer formed on a surface of the first substrate on the liquid crystal layer side. A first electrode, a transflective layer formed on a surface of the second substrate on the liquid crystal layer side, a transparent second electrode formed between the transflective layer and the liquid crystal layer, An illuminating device disposed on a side of the second substrate opposite to the liquid crystal layer, and a liquid crystal driving voltage applied to the liquid crystal layer via the first and second electrodes when the illuminating device is turned on and off. A driving unit for driving the first and second electrodes so that the first and second electrodes are different for the same image. 3. The liquid crystal according to claim 1, wherein the semi-transmissive reflective layer is formed of a reflective film having an opening through which light from the illumination device can be transmitted in each pixel. apparatus. 4. The driving means comprises: first supply means for supplying a voltage to the first electrode; and switching the voltage supplied by the first supply means to a setting for reflective display according to the non-lighting. 4. The liquid crystal according to claim 1, further comprising: a first control unit that controls the first supply unit so as to switch to a setting for transmissive display according to the lighting. 5. apparatus. 5. The lighting device further comprises lighting switching means for switching between the lighting and the non-lighting in the lighting device, wherein the first switching is performed in synchronization with the switching operation by the lighting switching means.
The liquid crystal device according to claim 4, wherein the control unit switches the voltage supplied by the first supply unit to a setting for reflective display or a setting for transmissive display. 6. The driving unit includes: a second supply unit configured to supply a voltage to the second electrode; and a voltage supplied by the second supply unit is switched to a setting for a reflective display according to the non-lighting. 6. The liquid crystal according to claim 1, further comprising: a second control unit that controls the second supply unit so as to switch to a setting for transmissive display according to the lighting. 7. apparatus. 7. The second supply means supplies a voltage having an effective value of a magnitude corresponding to a gradation level indicated by gradation data to the second electrode, and the second control means controls each gradation level. The second supply means is controlled to switch the setting of each magnitude of the effective value to the setting for the reflective display according to the non-lighting and to the setting for the transmissive display according to the lighting. The liquid crystal device according to claim 6, wherein: 8. The liquid crystal device according to claim 1, further comprising a color filter between the transflective layer and the first substrate. 9. The liquid crystal device according to claim 1, wherein the transflective layer has irregularities. 10. An electronic apparatus comprising the liquid crystal device according to claim 1. Description: