JPH11183891A - Liquid crystal display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display element capable of displaying a color picture with high color quality on a sufficiently bright screen. SOLUTION: Red, green and blue color filters 14R, 14G, 14B are allowed to correspond to respective pixel areas A so as to exclude their center areas, each pixel area A is constituted of a peripheral area (colored light exiting area (a)) corresponding to each of the color filters 14R, 14G, 14B and a center area (non-colored light exiting area (b)) not corresponding to any color filter and a color pixel with high luminance is displayed by colored light to be exit light from the peripheral area and a non-colored light with high luminance to be exit light from the center area. Thus even when the film thickness of the color filters 14R, 14G, 14B is thickness capable of obtaining colored light with high color purity, the luminance of a color pixel displayed in each pixel area A can be sufficiently improved and a color picture with a sufficiently bright, good color balance and high contrast can be displayed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device having a plurality of colored films having different transmission wavelength bands of light.

[0002]

2. Description of the Related Art A liquid crystal display element comprises a pair of front and rear substrates arranged opposite to each other, a plurality of first electrodes provided on an inner surface of one of the substrates, and at least one electrode provided on an inner surface of the other substrate. It comprises a second electrode and a liquid crystal layer provided between the pair of substrates.

There are two types of liquid crystal display devices: a transmissive type that displays by using light from a backlight, a reflective type that displays by using external light such as natural light or indoor illumination light, and There is a so-called two-way display type in which both a display of a type and a reflection type are performed. A transflective plate is provided on the back side of the substrate.

As a liquid crystal display element, a TN (twisted nematic) in which liquid crystal molecules of the liquid crystal layer are twisted at a predetermined twist angle between both substrates.
In this TN type liquid crystal display device, polarizing plates are arranged on the front surface of the front substrate and the rear surface of the rear substrate, respectively, with their transmission axes oriented in a predetermined direction. doing.

There are various types of liquid crystal display elements such as an active matrix type and a simple matrix type. For example, an active matrix type liquid crystal display element is arranged in a matrix on the inner surface of one substrate. A plurality of pixel electrodes, a plurality of active elements connected to the pixel electrodes, and a wiring for supplying a signal to the active element are provided, and an inner surface of the other substrate is opposed to the plurality of pixel electrodes. An electrode is provided, and the plurality of pixel electrodes and the opposing electrode are configured so that opposing regions thereof are each a pixel region.

Further, there are a liquid crystal display element for displaying a black-and-white image and a liquid crystal display element for displaying a multi-color image such as a full-color image. Are provided with colored films of a plurality of colors having mutually different transmission wavelength bands.

This colored film is generally a color filter of three colors of red, green and blue. Since each color filter emits most of the light transmitted through the pixel region as colored light, it is substantially the same as the pixel region. They are formed in the same area.

[0008]

However, in a liquid crystal display device having a conventional color filter, light in a wavelength band corresponding to the color of the color filter in the visible light band is transmitted through the color filter and colored light. Since the light in the other wavelength band is absorbed by the color filter, the intensity of the emitted colored light is extremely weak with respect to the intensity of the incident light, so that a bright screen cannot be obtained.

This problem can be alleviated to some extent by increasing the brightness of the backlight in the case of a transmissive display element. However, in the case of a reflective display element which makes display using external light, a liquid crystal display is used. Light that enters from the front of the display element passes through the color filter twice before being reflected by the reflector on the back side and exiting in front of the element, so that light absorption is large and the screen becomes considerably dark. .

Therefore, conventionally, it has been considered that the film thickness of the red, green and blue color filters is reduced to reduce the absorption of light by the color filters, and the light transmittance is increased to make the screen brighter. However, when the thickness of the color filter is reduced in this way, the transmittance of light in the absorption wavelength band is also increased, so that colored light with good color purity cannot be obtained.
A sufficient color range necessary for displaying a color image cannot be obtained.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a liquid crystal display device which has sufficient brightness of a screen, has a wide color range of display colors, and can display a color image with good color balance. .

[0012]

A liquid crystal display device according to the present invention comprises a pair of front and rear substrates arranged to face each other, a plurality of first electrodes provided on an inner surface of one of the substrates, and an inner surface of the other substrate. At least one second electrode provided on the inner surface of one of the pair of substrates, and a plurality of pixel regions where the plurality of first electrodes and the second electrode face each other. A plurality of colored films having different transmission wavelength bands provided in correspondence with each other, and a liquid crystal layer provided between the pair of substrates, wherein the plurality of colored films are respectively provided in the pixel region. The pixel regions correspond to each other except for the central region, and the pixel region includes a peripheral region to which the colored film corresponds and a central region to which the colored film does not correspond.

In the liquid crystal display device according to the present invention, each of the plurality of colored films corresponds to a pixel region except for a central region thereof, and the pixel region corresponds to a peripheral region to which the colored film corresponds. Since the colored film is composed of the central region that does not correspond, of the light that passes through the pixel region, light that passes through the surrounding region corresponding to the colored film absorbs light in the absorption wavelength band by the colored film. Light emitted as colored light and transmitted through the central region to which the colored film does not correspond is emitted as non-colored light with high brightness, and the colored light emitted from the peripheral region and the colored light emitted from the central region are emitted. High-luminance color pixels are displayed by the high-luminance uncolored light that is the emitted light.

Therefore, according to this liquid crystal display device, even if the thickness of the colored film is such that colored light with good color purity can be obtained, the brightness of the color pixels displayed by each pixel region is sufficient. And therefore the screen brightness is sufficient,
In addition, a color image with a wide color range and good color balance can be displayed.

Further, in this liquid crystal display element, the colored film is made to correspond to each of the pixel regions except for the central region thereof, so that a peripheral region of the pixel region to which the colored film corresponds is set as a colored light emission region. Since the non-colored light emission region is a central region that does not correspond to the colored film, even if the position of the colored film with respect to the pixel region is shifted due to a bonding error between the front and rear substrates when manufacturing the liquid crystal display element, There is no extreme bias in the brightness of the displayed pixels.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION In the liquid crystal display device of the present invention, as described above, a plurality of colored films are respectively made to correspond to each pixel region except for the central region, and the pixel region is formed by the colored film. A corresponding peripheral region and a central region to which the colored film does not correspond, a colored light that is emitted from the peripheral region of the pixel region, and a high brightness that is emitted light from the central region of the pixel region. By displaying a high-luminance color pixel with the non-colored light, the luminance of the color pixel displayed by each pixel region even if the thickness of the colored film is a thickness at which colored light with good color purity can be obtained. Is sufficiently high to display a color image with sufficient screen brightness and good color quality.

In the liquid crystal display device according to the present invention, each of the plurality of colored films is formed so that an outer peripheral portion thereof extends beyond an outer peripheral edge of the pixel region, and the colored films correspond to each other. The region to be colored (the region between the peripheral region of the pixel region and the adjacent pixel region) is defined as a colored light emitting region, and the region not corresponding to the colored film (the central region of the pixel region) is defined as a non-colored light emitting region. In this case, light transmitted through the peripheral region of the pixel region and light transmitted through the region between the pixel regions are absorbed by the colored film in the absorption wavelength band to become colored light. Therefore, a color image having a better color balance can be displayed without leakage of non-colored light from a region between the pixel regions.

Further, when the present invention is applied to a reflection type liquid crystal display device having a light reflection means on the back side, for example, the first electrode is a plurality of pixel electrodes arranged in a matrix, and In an active matrix type liquid crystal display device in which two electrodes are opposed electrodes facing the plurality of pixel electrodes, the plurality of pixel electrodes are disposed on an inner surface of a rear substrate of the pair of substrates. Preferably, a plurality of active elements respectively connected to the electrodes and wiring for supplying signals to the active elements are provided, and on the inner surface of the front substrate, the colored films of the plurality of colors and the counter electrode are preferably provided. With such a configuration, if the plurality of colored films are formed so that the outer peripheral edge of each colored film extends outward from the outer peripheral edge of the pixel region, the liquid crystal display element has Of the light incident from, since the light reflected by the wiring on the inner surface of the rear substrate is also emitted as colored light, preventing the shape of the wiring from being seen in a region between adjacent pixel regions, The image quality can be further improved.

In the outer peripheral portions of the colored films of a plurality of colors,
A light-shielding film may be arranged at the boundary between the adjacent colored film and the outer peripheral portion. With this light-shielding film, light can be prevented from being emitted from a gap where there is no colored film, which is caused by disposing the colored film apart, and a decrease in contrast can be prevented.

Further, when the colored films of a plurality of colors are, for example, red, green, and blue color filters, these color filters include a red filter thickness tR, a green filter thickness tG, and a blue filter thickness. Is less than tG <
tR <tB, and the area ratio sR of the red filter and the area ratio sG of the green filter with respect to the pixel region.
And the area ratio sB of the blue filter is sR>sB> sG
It is desirable that the color coordinates of the red light transmitted through the red filter on the color system, for example, the CIE1976L * a * b * color system,
The area of the color range surrounded by a triangle connecting the color coordinates of the green light transmitted through the green filter and the color coordinates of the blue light transmitted through the blue filter is increased, thereby deteriorating the chroma (C *) and color balance of each color. It is possible to improve the light transmittance without increasing the brightness of the screen, and to display a full-color image with good image quality.

[0021]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a front view of a part of the liquid crystal display device, and FIG.
FIG. 2 is a sectional view taken along the line II-II in FIG. The liquid crystal display element of this embodiment is of an active matrix type using a TFT (thin film transistor) as an active element, and a pair of front and rear substrates (a transparent substrate made of glass or the like) facing each other with a liquid crystal layer 19 interposed therebetween. Of the rear substrate 2
A plurality of transparent pixel electrodes 3 are arranged in a matrix on the inner surface of the
, Active elements (hereinafter, referred to as TFTs) 4 are provided.

In FIG. 1, among the pixel electrodes 3, (R)
Is a pixel electrode for displaying a red pixel, (G) is a pixel electrode for displaying a green pixel, and (B) is a pixel electrode for displaying a blue pixel. These pixel electrodes 3 are alternately arranged in a row direction (the horizontal direction of the screen) and arranged in a straight line. In the column direction (the vertical direction of the screen), the pixel electrodes 3 for displaying pixels of the same color are approximately separated from each other. They are arranged in a zigzag manner by being alternately shifted in the row direction by 1.5 pitches.

The TFT 4 is formed on the rear substrate 2, a gate electrode 5, a gate insulating film 6 covering the gate electrode 5, and formed on the gate insulating film 6 so as to face the gate electrode 5. And a source electrode 8 and a drain electrode 9 formed on both sides of the i-type semiconductor film 7 via an n-type semiconductor film (not shown).

On the rear substrate 2, a gate line 10 for supplying a gate signal to the TFT 4 in each row is provided along one side of each pixel electrode row. Each of the gate electrodes 5 is formed integrally with the gate wiring 10 corresponding to the row.

The gate insulating film (transparent film) 6 of the TFT 4 is formed over substantially the entire surface of the substrate 2, and the gate wiring 10 is covered with the gate insulating film 6 except for its terminal portions. .

On the gate insulating film 6, each TFT 4 of each column is arranged along one side of each pixel electrode column.
Are provided with data lines 11 for supplying data signals, and the drain electrodes 9 of the TFTs 4 in each column are respectively connected to the data lines 11 corresponding to the column.

The data wiring 11 is formed in a meandering shape along each pixel electrode column (a zigzag pixel electrode column) for displaying pixels of the same color, and is formed on the side edge of the pixel electrode 3 in each row. The horizontal wiring portions connecting the vertical wiring portions are arranged in parallel with the gate wiring 10 between adjacent pixel electrode rows.

In this embodiment, the data wiring 11 is wired on the gate insulating film 6, and the drain electrodes 9 of the TFTs 4 in each column are formed integrally with the data wiring 11 corresponding to that column. , The data wiring 11 is a TFT
4 is covered with an insulating film and wired thereon, and a drain hole 9 of the TFT 4 is formed in a contact hole provided in the insulating film.
May be connected.

The pixel electrode 3 is formed on the gate insulating film 6, and the pixel electrode 3 is connected to the source electrode 9 of the corresponding TFT 4 at one side edge.

Further, on the rear substrate 2, there is provided a capacitor wiring 12 corresponding to each pixel electrode row and facing each pixel electrode 3 of the row with the gate insulating film 6 interposed therebetween. In addition, the capacitance line 12, the pixel electrode 3, and the gate insulating film 6 between them form the pixel electrode 3 in the non-selection period.
A compensation capacitor (storage capacitor) for compensating the fluctuation of the potential of the storage capacitor is formed. The capacitance wiring 12
Are formed in parallel with the gate line 10 so as to face a portion slightly inward of the pixel electrode 3 from the edge of the pixel electrode 3 opposite to the TFT connection side.

The gate wiring 10 and the capacitance wiring 12 are formed of a metal film (for example, an aluminum alloy) having a low resistance and a high light reflectance, and the data wiring 11 is also a metal having a low resistance and a high reflectance. It is formed of a film. The surfaces of the gate line 10 and the capacitor line 12 are anodized to increase the dielectric strength between the pixel electrode 3 and the data line 11 formed on the gate insulating film 6.

On the inner surface of the rear substrate 2, that is, on the surface on which the pixel electrodes 3 and the TFTs 4, the data lines 11, and the like are formed, an alignment film 13 is provided over the entire pixel electrode array region.

On the other hand, on the inner surface of the substrate 1 on the front side, colored films of a plurality of colors having different transmission wavelength bands, for example, three colors of red, green and blue are provided.
The color filters 14R, 14G, and 14B are provided alternately in the row direction and the column direction in correspondence with the pixel electrodes 3.
Transparent protective film (insulating film) formed to cover 4G and 14B
A transparent opposing electrode 17 in the form of a single film is provided on the pixel electrode 16 so as to oppose all of the pixel electrodes 3, and the regions opposing the pixel electrodes 3 each form a pixel region A. A film 18 is formed. The protective film 16
Can be omitted by appropriately selecting the materials of the color filters 14R, 14G, and 14B.

The front substrate 1 and the rear substrate 2 are
A liquid crystal layer 19 is provided in a region between the two substrates 1 and 2 surrounded by the sealing material, and is joined to the peripheral portion via a frame-shaped sealing material (not shown).

The alignment films 13 and 18 provided on the inner surfaces of the pair of substrates 1 and 2 are each subjected to an alignment process by rubbing the film surfaces in a predetermined direction. The orientation of the liquid crystal molecules of the liquid crystal layer 19 in the vicinity of the respective substrates 1 and 2 is regulated by the alignment film 13 of the rear substrate 2 and the alignment film 18 of the front substrate 1. Twist angle (eg, approximately 9
0 °).

Further, polarizing plates 21 and 22 are disposed on the outer surfaces of the pair of substrates 1 and 2, respectively. These polarizing plates 21 and 22 are arranged so that their transmission axes are directed in predetermined directions. It is provided in.

The liquid crystal display device of this embodiment is in a state where no electric field is applied to the liquid crystal layer 19 (the liquid crystal molecules are oriented in the initial twisted state where the liquid crystal molecules are most inclined with respect to the substrates 1 and 2). The display in (state) is a bright display, and the application of an electric field to the liquid crystal layer 19 causes the liquid crystal molecules to rise and align with respect to the substrates 1 and 2 so that the light emission rate decreases and the display becomes dark. This is a TN type liquid crystal display element that performs so-called normally white mode display. For example, when the twist angle of liquid crystal molecules is approximately 90 °, the polarizing plates 21 and 22 make their transmission axes substantially orthogonal to each other. Provided.

Further, behind the polarizing plate 22 on the outer surface of the rear substrate 2, the light enters from the front of the liquid crystal display element and
A scattering reflection plate 23 is disposed as a reflection member for reflecting light transmitted through the light.

The red, green and blue color filters 14R, 14 provided on the inner surface of the front substrate 1 of the liquid crystal display device.
The color filters 14R, 14G, and 14B are filters using a pigment dispersion material.
G and 14B, the red filter 14R corresponds to the pixel region A where the (R) pixel electrode 3 and the counter electrode 17 for displaying a red pixel face each other, and the green filter 14R.
G corresponds to a pixel region A where the (G) pixel electrode 3 and the counter electrode 17 for displaying a green pixel are opposed to each other, and the blue filter 14B is a (B) pixel electrode 3 for displaying a blue pixel. And the counter electrode 17 correspond to the pixel region A facing each other.

These color filters 14R, 14G,
Each of the color filters 14B has an opening 15 in the center region thereof, and has an outer peripheral portion formed to protrude outside the outer peripheral edge of the pixel region A.
4R, 14G, and 14B correspond to each other, that is, a region between the pixel region A and a region between the adjacent pixel regions A (hereinafter, referred to as an inter-pixel region) is a colored light emission region a. A region to which 14G and 14B do not correspond, that is, a central region of the pixel region A is a non-colored light emission region b.

The color filters 14R, 14R for each color
The overhang width of G and 14B from the pixel area A is set to approximately １ ／ of the width of the area between the adjacent pixel areas A, and the side edges of the adjacent color filters 14R, 14G and 14B are Touching without gap.

FIG. 3 is a diagram showing the arrangement of the pixels and the color filters of the liquid crystal display element. The colored light emitting area a extends over the peripheral area of the pixel area A and the inter-pixel area at the outer peripheral edge of the pixel area A. (A hatched area in the drawing) colored light a ′ of red R, green G, or blue B, which is light emitted from a non-colored light emitting area b that is a central area of the pixel area A. It is indicated by the uncolored light b 'which is the emission light,
To the human eye, the entire pixel A 'appears to be colored in the color of the colored light, and a full-color image is displayed by the additive mixture of the red, green, and blue pixels A'. Therefore, the pixel A 'visible to the human eye is a high-brightness pixel in which the color of the colored light is slightly reduced, and the color density and brightness are determined by the light amount ratio between the colored light and the non-colored light. Corresponding to
For this reason, according to the liquid crystal display element, the colored light from the color filters 14R, 14G, and 14B has a sufficient color range, and the brightness of the color pixels displayed by each pixel region A can be sufficiently increased. .

The color filters 14R, 14R,
Each of the color filters 14G and 14B is formed to have a different film thickness for each color.
G and 14B are formed in different areas for each color by making the size of each opening 15 different.

The thicknesses and areas of the red, green, and blue color filters 14R, 14G, and 14B are shown in FIG.
A in the CIE1976L * a * b * color system shown in FIG.
The color coordinates RC of the red light transmitted through the red filter 14R on the * b * plane, the color coordinates GC of the green light transmitted through the green filter 14G, and the color coordinates BC of the blue light transmitted through the blue filter 14B are connected. The area of the color range surrounded by the triangle is substantially maximized, and the chroma (C *) of the mixed light of the red light, the green light, and the blue light indicated by the color coordinates WC is set to a value that is substantially minimized. .

That is, the red, green, and blue color filters 1
Among the 4R, 14G, and 14B, the thickness of the red filter 14R through which light in the long wavelength band is transmitted is tR, the area ratio to the pixel region A is sR, and the thickness of the green filter 14G through which light in the intermediate wavelength band is transmitted. Is tG, the area ratio is sG, the thickness of the blue filter 14B through which light in the short wavelength band is transmitted is tB, and the area ratio is sB. In this embodiment, each filter thickness is tG <tR <tB. And the filter area ratios are set to satisfy the relationship of sR>sB> sG, so that each point of the color coordinates RC, GC, and BC of light of red, green, and blue in the color system is set. Is large, and the chroma (C) of the mixed light of the red light, the green light, and the blue light in the color system is increased.
The color coordinates WC of the mixed light are made closer to the origin of the color coordinates (points of a * = 0, b * = 0) so that *) becomes small and achromatic.

The area of the color range on the a * b * plane in the color system is desirably 750 or more.
Chroma (C *) of the mixed light (distance from color coordinate origin)
Is desirably a value of 1.5 or less.

The red, green and blue color filters 14R,
More specifically, the film thickness and area of the red filter 14R will be described in this embodiment.
, The thickness tG of the green filter and the thickness t of the blue filter
B, the thickness of the red filter tR = 0.9 to 1.2 μm, the thickness of the green filter tG = 0.8 to 1.1 μm, the thickness of the blue filter tB = 1.1 to 1.4 μm, Area (area of pixel electrode 3) is 1
00%, the area ratio sR of the red filter 14R
The area ratio sG of the green filter 14G and the area ratio sB of the blue filter 14B are calculated as follows: red filter area ratio sR = 90 to 95% green filter area ratio sG = 60 to 65% blue filter area ratio sB = 75 to 80 %.

The filter area ratios sR, sG, s
Each of the values of B is a color filter 14R, 14R for each color.
G, the area of the portion corresponding to the pixel region A of 14B,
That is, the ratio is an area not including the portion corresponding to the inter-pixel region.

The liquid crystal display element performs reflection type display using external light. Light incident from the front of the element is converted by a front polarizing plate 21 into light having a polarization component along its absorption axis. The light is absorbed and converted into linearly polarized light having a polarization component along the transmission axis, enters the liquid crystal layer 19, is rotated by birefringence in the process of transmitting the light through the liquid crystal layer 19, is emitted forward of the element, and is observed. You.

The light transmitted through the liquid crystal layer 19 is incident on the rear polarizing plate 22, and of the light, light having a polarization component along the transmission axis of the rear polarizing plate 22 is transmitted through the polarizing plate 22. As a result, the image light is reflected by the scattering reflector 23, sequentially transmitted through the rear polarizing plate 22, the liquid crystal layer 19, and the front polarizing plate 21, and emitted to the front of the device.

The gate wiring 10 and the data wiring 11 provided on the inner surface of the rear substrate 2 pass through the inter-pixel region, and the capacitance wiring 12 crosses the pixel region A and the inter-pixel region. Of the light incident from the front surface of the liquid crystal display element, the light incident on the portion where the gate wiring 10 and the data wiring 11 and the capacitance wiring 12 pass is a reflection plate 23.
However, since the gate wiring 10, the data wiring 11 and the capacitor wiring 12 are formed of a metal film having high reflectivity, light incident on these wiring portions is also reflected.

In this liquid crystal display device, the red, green, and blue color filters 14R, 14G, and 14B are used.
Correspond to the pixel area A except for a central area thereof, and the pixel area A corresponds to the color filter 14.
R, 14G, and 14B correspond to the surrounding area and the color filters 14R, 14G, and 14B do not correspond to the central area.
The light transmitted through the peripheral area of the pixel area A is absorbed by the color filters 14R, 14G, and 14B in the absorption wavelength band and becomes colored light colored by the color filter. Emits forward. The intensity of the colored outgoing light changes according to the change in the alignment state of the liquid crystal molecules due to the electric field applied between the electrodes 3 and 18.

Of the light incident on each of the pixel areas A, the light transmitted through the central area of the pixel area A is reflected as non-colored light without passing through the color filters 14R, 14G, and 14B, and is reflected in front of the element. Out. The intensity of the uncolored outgoing light also changes according to the change in the alignment state of the liquid crystal molecules due to the electric field applied between the electrodes 3 and 18.

That is, in this liquid crystal display element, in all the pixel regions A, light incident from the front of the liquid crystal display element is reflected by the scattering reflector 23 on the rear side or the capacitance wiring 12 and emitted to the front side. Of the transmitted light, light that passes through the surrounding area corresponding to the color filters 14R, 14G, and 14B is emitted as colored light, and is emitted.
Light transmitted through the central region to which R, 14G, and 14B does not correspond is emitted as high-luminance non-colored light, so that high-luminance non-colored light and high-luminance color pixels can be displayed.

This liquid crystal display element performs a display in a normally white mode. In a pixel-to-pixel region where liquid crystal molecules always in an electric field-free state are always aligned in an initial twisted state, incident light is reduced. The light is reflected by the scattering reflector 23, the gate wiring 10, the data wiring 11 or the capacitance wiring 12, and is emitted to the front.
14G and 14B are formed so that their outer peripheral portions project outward beyond the outer peripheral edge of the pixel region A, so that the light transmitted through the inter-pixel region also transmits the color filters 14R, 14G and 14B.
B, and transmits the color filters 14R, 14G, 14
The light becomes a colored light colored B and is emitted to the front of the element.
The colored light emitted from the inter-pixel region is always light having the same intensity as long as the intensity of incident external light is constant.

Further, in the liquid crystal display device, the color filters 14R, 14G, and 14B are each provided in the pixel area A.
To the color filters 14R, 14G, and 14 of the pixel area A.
The surrounding area corresponding to B is a colored light emitting area a, and the central area not corresponding to the color filters 14R, 14G, 14B is a non-colored light emitting area b. Even when the position of the color filters 14R, 14G, and 14B deviates from the pixel area A where the pixel electrode 3 and the counter electrode 18 are opposed to each other due to the bonding error of 2, the brightness of the displayed pixel A 'is extremely low. There will be no significant bias.

That is, the pixel region A is composed of a colored light emitting region and a non-colored light emitting region, and a colored pixel with high luminance is displayed by the colored light and the non-colored light emitted from these regions. As means for performing this, color filters 14 for each color are used.
The outer shapes of R, 14G, and 14B are made smaller than the pixel area A, and these color filters 14R, 14G, and 14B are provided corresponding to the center of each pixel area A, respectively. , 14G, 14
An arrangement as shown in FIG. 6 is also conceivable in which a central region corresponding to B is a colored light emission region, and a peripheral region not corresponding to the color filters 14R, 14G, and 14B is a non-colored light emission region.

FIG. 6 shows a pixel and a color filter of a liquid crystal display element (hereinafter referred to as a comparative example) in which color filters having an outer shape smaller than the pixel area are provided corresponding to the center of each pixel area as described above. It is a figure showing an arrangement.

In this comparative example, each pixel A ′ is composed of a colored light a ′ of red R, green G, and blue B, which is light emitted from the central area of the pixel area A, and a peripheral area of the pixel area A. And the non-colored light b 'which is the light emitted from the non-colored light emission region.

Also in this comparative example, the thickness tR of the red filter and its area ratio sR, and the thickness tR of the green filter
G and its area ratio sG, and the thickness tB of the blue filter and its area ratio sB are represented by tG <tR <tB, sR> s.
B> sG is set.

However, in this comparative example, the color filter 14 for the pixel area A is not used due to a joining error between the front and rear substrates.
When the positions of R, 14G, and 14B deviate, an extreme deviation occurs in the brightness of the displayed pixel A '.

FIGS. 5 and 7 are diagrams showing the arrangement of pixels and color filters of the above embodiment and the comparative example when the positions of the color filters 14R, 14G, 14B with respect to the pixel area A are shifted. FIG. 5 shows an arrangement of pixels and color filters according to the embodiment, and FIG. 7 shows an arrangement of pixels and color filters at which misalignment has occurred in the comparative example.

As shown in FIG. 7, in the comparative example, for example, as shown in FIG.
When the positions of R, 14G, and 14B are shifted to the left, the emission width of the non-colored light b 'from the left region of the pixel region A is reduced, and the non-colored light b' from the right region of the pixel region A is correspondingly reduced. The emission width of is increased.

The brightness of the uncolored light b 'is
Since the brightness of the colored light a 'emitted from the central area of the pixel area A is much higher than that of the pixel area A, if the emission width of the non-colored light b' is different between the left and right of the pixel area A, the brightness of the displayed pixel A ' In addition, an extreme deviation occurs, in which the left-side luminance where the emission width of the uncolored light b 'is large is increased.

On the other hand, in the above embodiment, the pixel A '
Are colored light a ′ emitted from the peripheral area of the pixel area A ′, high-luminance non-colored light b ′ emitted from the peripheral area of the pixel area A ′,
Therefore, even if the positions of the color filters 14R, 14G, and 14B deviate from the pixel area A as shown in FIG. 5, the luminance distribution of the displayed pixel A 'has a high central luminance. , The luminance around the pixel A ′ is low, and therefore, the brightness of the pixel A ′ does not have an extreme bias.

Further, in the above embodiment, the color filters 14R, 14G, and 14B of the respective colors are formed so that the outer peripheral portions of the color filters 14R, 14G, and 14B project outside the outer peripheral edge of the pixel region A, respectively. , 14G, 14
A region corresponding to B, that is, a peripheral region of the pixel region A and an inter-pixel region between adjacent pixel regions are defined as a colored light emitting region a, and a region not corresponding to the color filters 14R, 14G, and 14B, that is, a pixel The central region of the region A is a non-colored light emitting region b. Therefore, light transmitted through the peripheral region of the pixel region A and light transmitted through the inter-pixel region are absorbed by the color filters 14R, 14G, and 14B. Since light in the wavelength band is absorbed and emitted as colored light, leakage of non-colored light from the inter-pixel region can be eliminated, and a color image with better color balance and contrast can be displayed.

In the above embodiment, the pair of substrates 1 and 2
The pixel electrodes 3, the TFTs 4, the gates, the data lines 10, 11 and the capacitance lines 12 are provided on the inner surface of the rear substrate 2, and the color filters 14R, 1 are provided on the inner surface of the front substrate 1.
4G, 14B and the opposing electrode 18, and the color filters 14R, 14G, 14B are formed so that the outer peripheral portions of the color filters 14R, 14G, 14B project outside the outer peripheral edge of the pixel region A, respectively. The wirings 10 and 1
The image quality can be improved by preventing the shapes 1 and 12 from being seen.

That is, for example, contrary to the above-described embodiment, the pixel electrode 3, the TFT 4, and the wirings 10, 11, and 12 are provided on the inner surface of the front substrate 1, and the color filter 14 R is provided on the inner surface of the rear substrate 2. , 14G, 14B and the counter electrode 18, the light incident on the liquid crystal display element from the front surface is exposed to the wires 10, 11, 1 on the inner surface of the front substrate 1.
2, each wiring 1 is located in the inter-pixel region.
In addition to seeing the shapes 0, 11, and 12, the pixel area A
The shape of the capacitance wiring 12 can be seen inside.

Further, as in the above embodiment, the pixel electrode 3, the TFT 4 and the wirings 10 and 1 are formed on the inner surface of the rear substrate 2.
Even if the outer peripheral edges of the color filters 14R, 14G, and 14B provided on the inner surface of the front substrate 1 do not protrude outside the outer peripheral edge of the pixel region A, the liquid crystal display element may have the front surface. , And the light reflected by the wirings 10, 11, 12 on the inner surface of the rear substrate 1 is emitted to the front surface as non-colored light of high luminance. Can be seen.

However, in the above embodiment, of the light incident on the liquid crystal display element from the front surface, the light reflected by the wirings 10, 11, and 12 on the inner surface of the rear substrate 2 is also emitted as colored light. Therefore, the shapes of the wirings 10, 11, and 12 are not seen in the pixel region A or the inter-pixel region.

Further, in the above embodiment, red, green,
The outer peripheral portions of the blue color filters 14R, 14G, 14B are made to protrude outside the outer peripheral edge of the pixel area A, and the color filters 14R, 14G, 14B of the respective colors are provided.
The film thicknesses tR, tG, tB and the area ratios (area ratios of the portions corresponding to the pixel regions A) sR, sG, sB are represented by tG <tR <t.
B, sR>sB> sG, so that FIG.
, The color coordinates RC of the red light transmitted through the red filter 14R, the color coordinates GC of the green light transmitted through the green filter 14G, and the blue light transmitted through the blue filter 14B in the CIE1976L * a * b * color system shown in FIG. While increasing the area of a color range surrounded by a triangle connecting the color coordinates BC and reducing the chroma (C *) of the mixed light of the red light, the green light, and the blue light in the color system, The color coordinates WC of the mixed light can be made closer to the color coordinate origin (a * = 0, b * = 0).

That is, like the arrangement of the pixels and the color filters in the above embodiment, the thickness tR of the red filter 14R
Is 0.9 to 1.2 μm, and the thickness tG of the green filter 14G is
Is 0.8 to 1.1 μm, and the film thickness tB of the blue filter 14B.
Is set to 1.1 to 1.4 μm, and the red filter 14
The area ratio sR of the portion corresponding to the pixel region of R is 90 to 95% of the area of the pixel region A, the area ratio sG of the portion corresponding to the pixel region of the green filter 14G is 60 to 65% of the area of the pixel region A, and the area ratio sR of the blue filter 14B. When the area ratio sB of the pixel region corresponding portion is set to 75% to 80% of the area of the pixel region A, the area of the color range in the CIE1976L * a * b * color system is substantially reduced as shown in FIG. It is possible to minimize the chroma (C *) of the mixed light of the red light, the green light and the blue light by making it maximum.

In FIG. 4, the color coordinates R indicated by black circles
C, GC, BC, WC are red,
The thicknesses tR, tG, tB of the green and blue color filters 14R, 14G, 14B and the area ratios sR, s of the portions corresponding to the pixel regions.
These are the color coordinates of the light of each color and the mixed light when G and sB are set to the values in the above range, and the area of the color range (the range surrounded by the triangle indicated by the solid line in the figure) performs full color display. 750 or more, which is a value necessary to display a large number of colors sufficient for the display.

Further, in the above embodiment, the chroma (C *) of each color of red, green, and blue (the color coordinate R of the light of each color from the color coordinate origin)
C, GC, and BC) are all sufficiently large, and the chroma (C *) of the mixed light is 1.5 or less, which is a value necessary for performing white display with substantially no coloring. Therefore, the color coordinate WC of the mixed light is very close to the color coordinate origin.

On the other hand, in FIG. 4, the color coordinates RC, GC, BC, and WC indicated by white circles are the red, green, and blue color filters 14R, 14G, and 14C in the comparative example shown in FIG.
14B are color coordinates of light of each color and mixed light when the film thicknesses tR, tG, and tB and the area ratios (the area of the entire filter in this comparative example) sR, sG, and sB are set to the same values as those in the above-described embodiment. In this comparative example, although the area of the color range (the area surrounded by the triangle indicated by the broken line in the figure) is sufficient, the chroma (C *) of the mixed light is larger than that of the above embodiment, Becomes farther from the color coordinate origin.

FIG. 8 shows a color filter 14 for red, green and blue.
R, 14G, and 14B thicknesses tR, tG, and tB and area ratio s
The spectral distribution characteristics of the emitted light of the above-described example and the comparative example when R, sG, and sB are respectively set to the values in the above ranges are shown. The solid line is the spectral characteristic of the example, and the broken line is the spectral characteristic of the comparative example. It is a characteristic.

In FIG. 8, R, G, and B represent red, green, and blue colored lights, which are emitted lights from the colored light emitting areas a corresponding to the color filters 14R, 14G, and 14B of each pixel area A. W indicates a spectral distribution, and W is a mixture of the red, green, and blue colored light and the non-colored light that is the non-colored light emitted from the non-colored light emission area b to which the color filters 14R, 14G, and 14B do not correspond. 2 shows a spectral distribution.

In the comparative example, a color filter having an outer shape smaller than the pixel area is provided corresponding to the center of each pixel area. The spectral distribution W of the mixed light in this comparative example is It is a spectral distribution including non-coloring emitted from the inter-region.

As shown in FIG. 8, the liquid crystal display device of the above embodiment has red, green, and blue color filters 14R, 14G,
Since the outer peripheral portion of the pixel region 14B extends beyond the outer peripheral edge of the pixel region A, not only the emitted light from the colored light emitting region a of the pixel region A but also the emitted light from the inter-pixel region is a color filter. 14R, 14G, and 14B are colored lights in which light in the absorption wavelength band is absorbed. Therefore, the transmittance of mixed light is somewhat lower than that of the comparative example, but the transmittance is lower than that of the conventional reflective liquid crystal display device. If much higher.

Further, in the liquid crystal display device of the above embodiment, the red, green, and blue colored lights R, G, and B from each pixel area A have better color purity than the comparative example. Is a light having a good transmittance balance, and the mixed light is a good white light having a high transmittance and almost no color.

For this reason, according to the liquid crystal display device of the above embodiment, the light transmittance is improved without deteriorating the chroma (C *) and the color balance of each color of red, green, and blue, and the screen is sufficiently displayed. Brightness can be obtained, and therefore, a full-color image with good image quality can be displayed.

The liquid crystal display device of the above embodiment has red,
The pixel electrodes 3 for displaying green and blue pixels are alternately arranged in a row direction and arranged linearly, and the pixel electrodes 3 for displaying pixels of the same color are arranged in a column direction at about 1.5 pitches. It is a so-called mosaic array type, which is arranged in a zigzag manner by alternately shifting each in the row direction.
The present invention can also be applied to a so-called grid-type liquid crystal display element in which pixel electrodes 3 for displaying blue pixels are arranged linearly in both the row direction and the column direction.

In the liquid crystal display device of the above embodiment, the color filters 14R, 14G, and 14B of the respective colors are formed such that the side edges of the adjacent color filters 14R, 14G, and 14B are
Although provided without any gap, a light-shielding film may be arranged at a boundary between the adjacent color filters 14R, 14G, and 14B. This light-shielding film allows the adjacent color filter 1
4R, 14G, and 14B can prevent light from exiting from a gap without a colored film caused by being spaced apart, and a light shielding film and a color filter 14R, 14G,
14B may be partially laminated, and the color filter 14B
The positioning accuracy when arranging the R, 14G, and 14B is relaxed, and the manufacturing is facilitated.

Further, in the above embodiment, a color filter is used as a colored film, but the colored film is not limited to a color filter. Further, the liquid crystal display device of the above embodiment is
Although a full-color image is displayed by mixing colors of red, green, and blue light, the present invention includes three color films (for example, color filters) of magenta, yellow, and cyan. The present invention can also be applied to a liquid crystal display device that displays a full-color image by mixing colored magenta, yellow, and cyan light. In this case, the thickness and area of the colored film of each color are respectively set to CIE1976L * a * b.
* On the color system, the color coordinates of the colored light transmitted through the colored film of the first color, the color coordinates of the colored light transmitted through the colored film of the second color, and transmitted through the colored film of the third color. By setting the area of the color range surrounded by the triangle connecting the color coordinates of the colored light to a value that is almost maximal, the light transmittance can be reduced without deteriorating the chroma (C *) and color balance of each color. The screen can be made sufficiently bright by improving the screen.

The present invention is not limited to the active matrix type using a TFT as an active element, but also an active matrix type liquid crystal display element using an MIM as an active element, or a scanning electrode extending in one direction on the inner surface of one substrate. Can be applied to a simple matrix type liquid crystal display device or the like in which a plurality of signal electrodes are provided in parallel with each other, and a plurality of signal electrodes along the direction intersecting with the scanning electrodes are provided in parallel on the inner surface of the other substrate.

Further, in the liquid crystal display device of the above embodiment, the polarizing plates 21 and 22 are disposed on the front and rear surfaces, respectively.
A scattering reflection plate 23 is arranged as a light reflection means on the back side of the substrate. Instead, for example, an electrode (the pixel electrode 3 in the above embodiment) provided on the inner surface of the rear substrate 2 is formed of a metal film. The electrode may also serve as the reflecting means,
In that case, the polarizing plate may be only the front polarizing plate 21.

Also, as in the above embodiment, the front polarizing plate 21
And the rear polarizing plate 22, the rear polarizing plate 2
2, a reflection plate 23 disposed on the back side is a semi-transmission reflection plate,
Further, a backlight may be disposed behind the backlight, and in this case, a so-called two-way display is used which performs both a reflective display using external light and a transmissive display using light from the backlight. Liquid crystal display element. further,
If a backlight is arranged in place of the light reflecting means on the back side, a transmissive liquid crystal display element using only light from the backlight is obtained.

[0088]

According to the liquid crystal display device of the present invention, a pair of front and rear substrates arranged opposite to each other, a plurality of first electrodes provided on an inner surface of one of the substrates, and an inner surface of the other substrate are provided. At least one second electrode and an inner surface of one of the pair of substrates, the plurality of first electrodes and the second electrode corresponding to a plurality of pixel regions facing each other. And a liquid crystal layer provided between the pair of substrates, wherein the plurality of color films each have a central region in the pixel region. The pixel region includes a peripheral region to which the colored film corresponds and a central region to which the colored film does not correspond.

According to this liquid crystal display element, even if the thickness of the colored film is such that colored light with good color purity can be obtained,
The brightness of the color pixels displayed by each pixel region is sufficient, and therefore, the brightness of the screen is sufficient, the color range of the display colors is wide, and a color image with good color balance and contrast can be displayed.

Further, in this liquid crystal display element, the colored films correspond to the pixel regions except for the central region thereof, so that the peripheral region of the pixel region to which the colored films correspond corresponds to the colored light emitting region. Because the non-colored light emission region is a central region that does not correspond to the colored film, even if the position of the colored film with respect to the pixel region is shifted due to a bonding error between the substrates before and after manufacturing the liquid crystal display element. ,
There is no extreme bias in the brightness of the displayed pixels.

Further, in the liquid crystal display device according to the present invention, each of the plurality of colored films is formed so that an outer peripheral portion thereof extends beyond an outer peripheral edge of the pixel region. Region to be colored light emission region,
Since the region that the colored film does not correspond to is a non-colored light emission region, light transmitted through the peripheral region of the pixel region and light transmitted through the region between the pixel regions are converted into light in the absorption wavelength band by the colored film. Because the light is absorbed and emitted as colored light, leakage of non-colored light from a region between the pixel regions is eliminated,
A color image with better color balance and contrast can be displayed.

When the present invention is applied to a reflection type liquid crystal display device having a light reflecting means on the back side, for example, the first electrode is a plurality of pixel electrodes arranged in a matrix, and In an active matrix type liquid crystal display device in which two electrodes are opposed electrodes facing the plurality of pixel electrodes, the plurality of pixel electrodes are disposed on an inner surface of a rear substrate of the pair of substrates. A plurality of active elements respectively connected to the electrodes, and a wiring for supplying a signal to the active elements are provided.On the inner surface of the front substrate, the colored films of the plurality of colors and the counter electrode are provided. If the outer peripheral edge of each colored film is formed so as to protrude outside the outer peripheral edge of the pixel region, of the light incident on the liquid crystal display element from the front side, the rear substrate Since the light reflected by the wiring in the plane is also emitted as a colored light, prevents the visible shape of the wiring in the region between the pixel regions, it is possible to improve the more image quality.

Further, when the colored films of a plurality of colors are, for example, red, green, and blue color filters, these color filters include a red filter thickness tR, a green filter thickness tG, and a blue filter thickness. Is less than tG <
tR <tB, and the area ratio sR of the red filter and the area ratio sG of the green filter with respect to the pixel region.
And the area ratio sB of the blue filter is sR>sB> sG
It is desirable that the color coordinates of the red light transmitted through the red filter on the color system, for example, the CIE1976L * a * b * color system,
The area of the color range surrounded by a triangle connecting the color coordinates of the green light transmitted through the green filter and the color coordinates of the blue light transmitted through the blue filter is increased, thereby deteriorating the chroma (C *) and color balance of each color. It is possible to improve the light transmittance without increasing the brightness of the screen, and to display a full-color image with good image quality.

[Brief description of the drawings]

FIG. 1 is a front view of a part of a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a diagram showing an arrangement of pixels and color filters of the liquid crystal display element.

FIG. 4 shows CIE1976 of the liquid crystal display device and a comparative example.
The figure which shows the color coordinate of the red, green, blue coloring light in the L * a * b * color system, the color range enclosed by the triangle which connects them, and the color coordinate of mixed light.

FIG. 5 is a diagram showing an arrangement of pixels and color filters when a position of a color filter is shifted from a pixel region in the liquid crystal display element.

FIG. 6 is a diagram showing an array of pixels and color filters in a comparative example in which color filters having an outer shape smaller than the pixel region are provided in correspondence with the center of each pixel region.

FIG. 7 is a diagram showing an arrangement of pixels and color filters when a position of a color filter is shifted from a pixel region in the comparative example.

FIG. 8 is a view showing spectral distribution characteristics of emitted light between the liquid crystal display element and a comparative example.

[Explanation of symbols]

 1, 2 ... substrate 3 ... pixel electrode 4 ... TFT (active element) 14R, 14G, 14B ... color filter 15 ... opening 18 ... counter electrode 21, 22 ... polarizing plate 23 ... reflector A ... pixel area a ... colored light emission Area b: Uncolored light emission area

Claims (6)

[Claims] 1. A pair of front and rear substrates arranged to face each other, a plurality of first electrodes provided on an inner surface of one of the substrates, and at least one second electrode provided on an inner surface of the other substrate. On the inner surface of any one of the pair of substrates,
A plurality of colored films having different transmission wavelength bands provided corresponding to a plurality of pixel regions in which the plurality of first electrodes and the second electrode face each other, and provided between the pair of substrates; A plurality of colored films, each of which corresponds to the pixel region except for a central region thereof, wherein the pixel region corresponds to a peripheral region to which the colored film corresponds, and A liquid crystal display device comprising a central region in which the film does not correspond. 2. An outer peripheral portion of each of the plurality of colored films extends outward from an outer peripheral edge of the pixel region.
The liquid crystal display element according to claim 1, wherein a region corresponding to the colored film is a colored light emitting region, and a region not corresponding to the colored film is a non-colored light emitting region. 3. The device according to claim 1, wherein the first electrode is a plurality of pixel electrodes arranged in a matrix, and the second electrode is a counter electrode facing the plurality of pixel electrodes.
Or the liquid crystal display element according to 2. 4. A light reflecting means is provided on the back side of the rear substrate,
Of the pair of substrates, on the inner surface of the rear substrate, the plurality of pixel electrodes, a plurality of active elements respectively connected to these pixel electrodes, and a wiring for supplying a signal to the active element are provided, The liquid crystal display device according to claim 3, wherein the plurality of color films and the counter electrode are provided on an inner surface of the front substrate. 5. The color film according to claim 1, wherein the plurality of color films are red, green, and blue color filters.
3. The liquid crystal display device according to item 1. 6. The thickness tR of the red filter, the thickness tG of the green filter, and the thickness tB of the blue filter are tG
<TR <tB, and the area ratio sR of the red filter to the pixel region and the area ratio s of the green filter
G and the area ratio sB of the blue filter are sR>sB> s
The liquid crystal display element according to claim 5, wherein the liquid crystal display element has a relationship of G.