JPH08114818A - Thin-film transistor type liquid crystal display device - Google Patents

Abstract

PURPOSE: To obtain a liquid crystal image display of a wide visual field angle and high grade by having a wide visible range of a high contrast ratio having symmetry in prescribed visual angle directions and eliminating a gradation inversion at the prescribed visual angle and voltage. CONSTITUTION: Pixel electrodes 1 or counter electrodes 17 varying in height are formed on at least one of glass substrates 7A, 7B of a pixel electrode substrate (TFT substrate) 1 or counter electrode substrate 2 in the effective display region of the pixel parts of a thin-film transistor type liquid crystal display device, by which liquid crystal domains varying in electro-optical characteristics are generated within the prescribed regions of the pixels. The display images over the entire part of the liquid crystal display device eventually display the average of the visual angle-transmission curve of different kinds of liquid crystal domains generated within the pixels if the device is formed in such a manner and, therefore, the wide visible range of the high contrast ratio having the symmetry in the vertical and lateral visual angle directions is obtd. and the gradation inversion at the prescribed visual angle and voltage does not arise any more.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film transistor type liquid crystal display device using a thin film transistor (hereinafter referred to as TFT).

[0002]

2. Description of the Related Art FIG. 9 is a partial sectional view of a channel portion of a TFT in a conventional thin film transistor type liquid crystal display device. In FIG. 9, in the TFT substrate (1), the glass substrate 7
Pixel electrode 1, first insulating film 8, gate electrodes 2, 5 on A
(TFT portion, pre-stage gate portion) are formed in this order, and a gate oxide film 9, a semiconductor layer 10, and an ohmic contact layer 12 are sequentially formed thereon. Then, drain electrodes 4, 6 (TFT portion, pre-stage gate portion) and source electrode 3 are formed thereon, and a second insulating film 11 is formed thereon.

FIG. 10 is a partial sectional view of a conventional thin film transistor type liquid crystal display device. In FIG. 10, the TFT substrate
The counter electrode substrate (2) facing the liquid crystal 20 with (1) is a black matrix layer on the glass substrate 7B (downward in the drawing).
14, the color filter layer 15 is formed, and the protective film 16 is formed thereon.
Are formed. Then, the counter electrode 17 is formed thereon, and the alignment films 18A and 18B are formed on both the TFT substrate (1) and the counter electrode substrate (2).
The cell thickness d is maintained between 18A and 18B, and the liquid crystal 20 is injected therein. Polarizing plates 19A and 19B are provided on the outer surfaces of the TFT substrate (1) and the counter electrode substrate (2). TFT substrate
The configuration of (1) is the same as that of FIG.

FIG. 11 is an alignment regulation state diagram of liquid crystal molecules sandwiched between a TFT substrate (1) and a counter electrode substrate (2) of a conventional thin film transistor type liquid crystal display device. TF shown in FIG.
The alignment film 18A of the T substrate (1) has a direction 23a, 24a, 25a, 26a inclined by 45 degrees with respect to the transistor wiring or the pixel electrode 1.
The surface of the alignment film 18B on the counter electrode substrate (2) is surface-treated (AR side rubbing), and the surface is formed in a direction 23b, 24b, 25b, 26b inclined by 90 degrees with respect to the direction of the alignment treatment of the alignment film 18A. It has been processed (rubbing on the CF side). However, both boards (1),
The combination of the alignment directions between (2) is because the twisting and turning direction of the liquid crystal molecules is determined by the optically active compound contained in the nematic liquid crystal in a small amount. The combinations of the alignment directions of the alignment films between the substrates (1) and (2) are (23a, 23b) and (24a, 24b).

On the other hand, if the liquid crystal molecules have a left-handed twist alignment, the combination of the alignment directions of the alignment films between the substrates (1) and (2) is (25a, 25b), (26a, 26b). As a result, a stable monodomain is formed in the liquid crystal display cell by combining the liquid crystal molecule alignment regulating direction of the alignment films 18A and 18B and the twisting and rotating direction of the liquid crystal molecules.

FIG. 12 is a characteristic diagram showing the contrast ratio dependence of the conventional thin film transistor type liquid crystal display device with respect to the incident angle in the vertical viewing angle direction. However, the incident angle in the normal direction of the liquid crystal display cell is 0 degree, the upward direction is shown as a plus angle, and the downward direction is shown as a minus angle. The viewing angle characteristics in the range of the contrast ratio of 10: 1 are 25 degrees above and 60 degrees below, and the contrast ratio distribution curve 27 in the vertical direction has an asymmetric shape. Incidentally, in the left-right viewing angle range, the contrast ratio distribution curve in the left-right direction has a symmetrical shape, and for example, the viewing angle characteristics in the range of the contrast ratio of 10: 1 are 50 degrees to the right and 50 degrees to the left.

FIG. 13 shows a transmittance-dependent characteristic diagram (VT curve in the front direction) of 8-gradation display in the vertical viewing angle direction in a conventional thin film transistor type liquid crystal display device. However,
The incident angle in the normal direction of the liquid crystal display cell is 0 degrees, the upper direction is positive and the lower direction is negative. Here, the transmittance T (%) is 100% when no voltage is applied. The gradation level (voltage level applied to the liquid crystal) is
As shown in FIG. 14, the maximum transmittance (T) in the applied voltage range (0 to 5 V) of the applied voltage (V) -transmittance T (%) curve in the front direction is shown.
8) and the minimum transmittance (T1) are divided into seven equal parts, and voltage values V (V8 to V1) corresponding to the respective transmittances T are used.

[0008]

For example, T1 corresponds to the voltage value V1 and T2 corresponds to the voltage value V2. The other correlations between the transmittance T and the voltage value V are also the same.
From this characteristic diagram, in the downward viewing angle direction, for example, when the applied voltage value is V1, the transmittance is the lowest at about 15 degrees, and when the applied voltage value is V2, the minimum transmittance is shown at about 20 degrees. Recognize. As a result, when displaying 8 gradations, the magnitude relation between gradations is guaranteed only within about 17 degrees, and in the lower viewing angle range beyond that, the reversal of the transmittance, that is, the gradation reversal phenomenon occurs, The image display state at that time is unnatural,
Virtually no image recognition is possible. Such a phenomenon is similarly explained for other adjacent applied voltage values.
Further, it can be seen that the viewing angle range in which the gradation inversion phenomenon does not occur becomes narrower at the higher gradation display. Incidentally, the transmittance dependence of the 8-gradation display with respect to the incident angle in the left-right viewing angle direction shows a symmetrical transmittance curve at each gradation level about the normal direction of the liquid crystal display cell, and it may occur in the lower viewing angle direction. The gradation inversion phenomenon can be seen at about 40 degrees.

Therefore, in the conventional thin film transistor type liquid crystal display device, the viewing angle range for maintaining a high contrast ratio in a good vertical balance is narrow in the vertical viewing angle direction, and the grayscale inversion that occurs at a predetermined voltage and viewing angle especially in the lower and horizontal directions. The phenomenon cannot be prevented, and there has been a demand for a thin film transistor type liquid crystal display device having a wide viewing angle design and having no problem of angle dependency.

The present invention achieves a symmetrical high contrast ratio in the vertical and horizontal viewing angle directions, and prevents grayscale inversion or abnormal high light-shielding phenomenon in the specific viewing angle direction. An object of the present invention is to provide a thin film transistor type liquid crystal display device capable of realizing a wide viewing angle and high display quality.

[0011]

In order to achieve the above object, the present invention provides a thin film transistor type liquid crystal display device according to claim 1, wherein thin film transistors are provided at intersections of gate electrodes and source electrodes arranged in a matrix. A pixel electrode substrate on which a pixel electrode is formed and connected to the drain electrode of the thin film transistor, and a counter electrode substrate on which a common counter electrode is formed and which is arranged so as to face the pixel electrode substrate with a liquid crystal interposed therebetween. And in at least one of the pixel electrode substrate and the counter electrode substrate, the pixel electrode or the counter electrode having a different height is formed in the effective display area of each pixel.

A thin film transistor type liquid crystal display device according to a second aspect is the thin film transistor type liquid crystal display device according to the first aspect, wherein a conductive thin film is provided on the pixel electrode, and the conductive thin film has a predetermined thickness and area. It will be adjusted to.

A thin film transistor type liquid crystal display device according to a third aspect is the thin film transistor type liquid crystal display device according to the first aspect, wherein a conductive thin film is provided on the counter electrode, and the conductive thin film has a predetermined thickness and area. It will be adjusted to.

A thin film transistor type liquid crystal display device according to a fourth aspect is the thin film transistor type liquid crystal display device according to the second and third aspects, in which at least one of the film thickness and the area of the conductive thin film is different between two adjacent pixels.

A thin film transistor type liquid crystal display device according to a fifth aspect is the thin film transistor type liquid crystal display device according to the first aspect, in which the conductive thin film is provided in a predetermined region on the pixel electrode and in a region other than the predetermined region. Is formed on the counter electrode.

A thin film transistor type liquid crystal display device according to a sixth aspect is the thin film transistor type liquid crystal display device according to the first aspect, wherein a conductive thin film is formed on at least one of the pixel electrode or the counter electrode, and the conductive thin film is formed.
It is formed with a film thickness of 0.1 μm or more.

[0017]

According to the structure of claim 1, in the effective display area of the pixel portion, at least one of the pixel electrode substrate and the counter electrode substrate is formed with pixel electrodes or counter electrodes having different heights. , Divided liquid crystal molecule array regions having different electro-optical characteristics are formed in a predetermined area in the pixel, and viewing angle characteristics of the thin film transistor type liquid crystal display device are obtained by averaging the electro-optical characteristics of the respective divided liquid crystal molecule array areas. As a result, a high-contrast ratio visual range having symmetry in a predetermined viewing angle direction can be obtained, and the gradation inversion phenomenon at a specific viewing angle and voltage can be avoided.

According to the second aspect of the invention, since the conductive thin film is provided on the pixel electrode and adjusted to have a predetermined film thickness and area, the viewing angle characteristic of the thin film transistor type liquid crystal display device is obtained. Is an average of the electro-optical characteristics of each divided liquid crystal molecule array region, and a high contrast ratio visual range with symmetry in a predetermined viewing angle direction is obtained, and gradation inversion at a specific viewing angle and voltage is achieved. The phenomenon is avoided.

According to the third aspect of the invention, since the conductive thin film is provided on the counter electrode and adjusted to have a predetermined film thickness and area, the viewing angle characteristics of the thin film transistor type liquid crystal display device. Is an average of the electro-optical characteristics of each divided liquid crystal molecule array region, and a high contrast ratio visual range with symmetry in a predetermined viewing angle direction is obtained, and gradation inversion at a specific viewing angle and voltage is achieved. The phenomenon is avoided.

According to the fourth aspect of the invention, at least one of the film thickness and the area of the conductive thin film is different between the two adjacent pixels, so that the same operation as the second and third aspects is achieved.

According to the structure of claim 5, the conductive thin film is provided in a predetermined region on the pixel electrode, and is simultaneously formed on the counter electrode in a region other than the predetermined region. The viewing angle characteristics of the thin film transistor type liquid crystal display device are obtained by averaging the electro-optical characteristics of the respective divided liquid crystal molecule alignment regions, and a high contrast ratio visual range having symmetry in a predetermined viewing angle direction can be obtained, The gradation inversion phenomenon at the viewing angle and the voltage is avoided.

According to the structure of claim 6, since the conductive thin film having a thickness of 0.1 μm or more is formed on at least one of the pixel electrode and the counter electrode, it has the same effect as in claims 2 and 3.

[0023]

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

FIG. 1 is a plan view of a TFT substrate (1) of a thin film transistor type liquid crystal display device according to a first embodiment of the present invention, and FIG. 2 is a sectional view of one pixel portion of FIG. In FIG. 1, the TFT substrate (1) has a structure in which a gate electrode 2 and a semiconductor layer 10 are formed between a source electrode 3 and a drain electrode 4,
The conductive thin film 13 is patterned on the pixel electrode 1, and an image signal is written from the drain electrode 4 to the pixel electrode 1.
In the figure, 6 is a drain electrode of a pre-stage gate section, which will be described later, and 21 and 22 are contact windows of the TFT section and the pre-stage gate section, respectively.

Further, in FIG. 2, the TF of the TFT substrate (1) is
The structure of the T portion is such that after the pixel electrode 1 and the first insulating film 8 are formed on the glass substrate 7A, the gate electrodes 2, 5 (T
FT section, front gate section), drain electrodes 4, 6 (TFT)
Part, pre-stage gate part), source electrode 3 and gate electrodes 2, 5
A gate oxide film 9 is formed to prevent a short circuit between them. Further, on the gate oxide film 9, the semiconductor layer 10,
The ohmic contact layer 12 and the source electrode 3 and the drain electrodes 4 and 6 are formed thereon. Then, the second insulating film 11 is formed thereon. Further, a conductive thin film 13 is formed on the pixel electrode 1. And TFT substrate
An alignment film 18A is formed on the surface of (1).

On the other hand, the film structure of the counter electrode substrate (2) is the same as the conventional film structure described in FIG.
A liquid crystal 20 is sandwiched while maintaining a distance between both substrates by interposing a spacer (not shown) between (1) and the counter electrode substrate (2). A polarizing plate is provided on the outer surface of both electrode substrates (1) and (2).
19A and 19B are provided.

The first embodiment and the second and later described later
In the third embodiment, the conductive thin film 13 formed on at least one of the pixel electrode 1 and the counter electrode 17 has a film thickness of 0.1 μm or more.

FIG. 3 shows a TFT substrate (1) and a counter electrode substrate (2) of the thin film transistor type liquid crystal display device shown in FIGS. 1 and 2.
FIG. 6 is a diagram showing an alignment regulation state of liquid crystal molecules sandwiched between and.
The alignment film 18A on the TFT substrate (1) has a direction 28a, 29a, 30a, 31a inclined 45 degrees with respect to the TFT wiring or the pixel electrode 1.
The surface of the alignment film 18B on the counter electrode substrate (2) is surface-treated (AR side rubbing), and the surface is formed in a direction 28b, 29b, 30b, 31b inclined by 90 degrees with respect to the direction of the alignment film 18A. It has been processed (rubbing on the CF side). Both electrode substrate shown above
The alignment treatment method of the alignment film (18A, 18B) surface of (1), (2) is
This is the same as the method of aligning the alignment film surface of the conventional thin film transistor type liquid crystal display device described in FIG.

In the first embodiment of the present invention, the combination of the orientation control direction on the surface of the orientation film and the twist rotation direction of the liquid crystal molecules is such that if the liquid crystal molecules have a right rotation twist orientation, both electrode substrates (1), The combination of the alignment directions of the alignment film between (2) is
(28a, 28b) and (29a, 29b). On the other hand, if the liquid crystal molecules have left-handed twist alignment, the combination of the alignment directions of the alignment films between the electrode substrates (1) and (2) is (30a, 30b), (31a,
31b).

FIG. 4 is a cross-sectional view of liquid crystal alignment in one pixel portion of the thin film transistor type liquid crystal display device shown in FIGS. When a voltage is applied between the pixel electrode 1 on the TFT substrate (1) and the counter electrode 17 on the counter electrode substrate (2), the liquid crystal molecules in the liquid crystal display cell rise up following the applied voltage.
At that time, the equipotential surface of the liquid crystal at the position where the conductive thin film 13 is formed on the pixel electrode 1 takes a distorted projection shape with respect to the equipotential surface at the position where the conductive thin film 13 is not formed, while the TFT portion
The potential of the equipotential surface of the liquid crystal on the pixel electrode near the (left side) and the front gate portion (right side) is smaller than that of the normal equipotential surface due to the effect of the second insulating film 11. As a result, the liquid crystal molecules can be separated from the edge interface of the conductive thin film 13 and the pixel electrode 1.
It is oriented in the direction perpendicular to the equipotential surface on the edge interface, and due to elastic distortion of the liquid crystal, it tends to diffuse continuously in the vertical and horizontal directions. Therefore, the liquid crystal molecules are conductive thin film 13
The liquid crystal alignment property which is left-right symmetric with respect to the normal direction near the center of is maintained.

On the other hand, a pattern arrangement in which the area or the film thickness of the conductive thin film 13 is different between adjacent pixels, for example, in terms of film thickness, the thick conductive thin film 13 and the thin conductive thin film 13 are arranged on the pixel on the gate line. Even if a pattern configuration in which the thick conductive thin film 13 and the thin conductive thin film 13 are alternately arranged is formed for the pixel configuration on the source line, the liquid crystal molecules in one pixel Although the alignment symmetry is not lost, adjacent pixels can have slightly different alignment forms. As a result, different electro-optical characteristics occur between adjacent pixels. A similar pattern arrangement can also be adopted in a method in which the area of the conductive thin film 13 is made different between adjacent pixels, and the liquid crystal behavior and alignment form at that time show the same tendency as that shown above.

FIG. 5 is a sectional view of one pixel portion of the thin film transistor type liquid crystal display device according to the second embodiment of the present invention. The structure of the counter electrode substrate (2) prevents light leakage from the gate electrodes 2 and 5, the source electrode 3, and the wiring of the TFT substrate (1) on the glass substrate 7B (downward in the drawing). For this purpose, a black matrix layer 14 is formed, and a color filter layer 15 and a protective film 16 are formed thereon. And
The counter electrode 17 is formed thereon. Further, the conductive thin film 13 is formed on the counter electrode 17. And
The alignment film 18B is formed.

On the other hand, the film structure of the TFT substrate (1) is shown in FIG.
This is the same as the conventional film structure described in.

The combination of the alignment regulating direction on the alignment film surface and the twisting and rotating direction of the liquid crystal molecules in the second embodiment of the present invention is also the same as that in FIG. 3 described in the first embodiment.

Further, in the thin film transistor type liquid crystal display device according to the second embodiment of the present invention, even in the pattern arrangement configuration in which the area or the film thickness of the conductive thin film 13 is different between the adjacent pixels, the liquid crystal molecules in the liquid crystal display cell are The orientation shows the same tendency as in the case of the first embodiment described with reference to FIG.

FIG. 6 is a sectional view of a pixel portion of a thin film transistor type liquid crystal display device according to the third embodiment of the present invention. As shown in FIG. 6, the conductive thin film 13 has a TFT substrate (1).
Of the conductive thin film 13 formed on the pixel electrode 1 of the TFT substrate (1) at the same time as the conductive thin film 13 on the counter electrode 17 of the counter electrode substrate (2). The patterning is formed in a region other than the above. Further, the conductive thin film 13 formed on both electrode substrates (1) and (2) can be patterned to have a predetermined film thickness and area. As a result, the liquid crystal molecules in the vicinity of the edges of the conductive thin films 13 facing each other on both electrode substrates (1) and (2) have the same orientation control direction, and the liquid crystal molecules are more strongly and stably controlled in the same orientation direction. Liquid crystal domains can be formed.

FIG. 7 is a contrast ratio dependence characteristic diagram with respect to an incident angle in the vertical viewing angle direction of the thin film transistor type liquid crystal display device in the first embodiment of the present invention. However, the incident angle in the normal direction of the liquid crystal display cell is 0 degree, the upward direction is shown as a plus angle, and the downward direction is shown as a minus angle. The vertical viewing angle-contrast distribution curve 27 is not symmetrical in the vertical direction as in the conventional example described in FIG. 12, but is a symmetrical contrast curve, and a higher contrast ratio can be obtained in a predetermined viewing angle range. it can. Also, with the thin film transistor type liquid crystal display device in the second and third embodiments of the present invention, the same viewing angle-contrast distribution characteristic diagram as in the first embodiment of the present invention can be obtained.

FIG. 8 is a transmissivity-dependent characteristic diagram of 8-gradation display in the vertical viewing angle direction in the thin film transistor type liquid crystal display device according to the first embodiment of the present invention. However, the incident angle in the normal direction of the liquid crystal display cell is 0 degree, the upward direction is shown as a plus angle, and the downward direction is shown as a minus angle. Each applied voltage value was determined by a method similar to the method shown in FIG. From the characteristic diagram shown in FIG. 8, symmetrical transmittance curves are drawn in the upper and lower viewing angle directions at each gradation level, and no viewing angle-transmittance curves intersect between adjacent curves. As a result, it is possible to avoid the appearance of the gradation inversion phenomenon which has been conventionally observed at a specific viewing angle and applied voltage.
By the way, the same tendency is exhibited in the left and right viewing angle directions. Also, the viewing angle-transmittance characteristic diagrams when the applied voltage in the gradation reversal viewing angle direction in the second and third embodiments of the present invention are used as parameters are similar to those of the first embodiment of the present invention as described above. Show a trend.

Therefore, the thin film transistor type liquid crystal display devices in the first, second and third embodiments of the present invention show a wide high contrast ratio visual range having symmetry in the vertical and horizontal viewing angle directions. The gradation inversion phenomenon that occurs at a specific voltage and viewing angle does not occur, and a natural image can be obtained at any voltage value when viewed from any viewing angle direction.

[0040]

As described above, according to the first aspect of the present invention.
According to the thin film transistor type liquid crystal display device described, in the effective display area of each pixel, at least one of the pixel electrode substrate and the counter electrode substrate is formed with a pixel electrode or a counter electrode having a different height. Divided liquid crystal molecule alignment regions having different electro-optical properties are formed in predetermined regions, and the electro-optical properties of the thin film transistor liquid crystal display device are the averaged electro-optical properties of the divided liquid crystal molecule alignment regions. , A high contrast ratio visual range with symmetry in a predetermined viewing angle direction can be obtained, gradation reversal phenomenon at a specific viewing angle and voltage can be avoided, and a natural image display without viewing angle dependency or voltage dependency can be realized. It is possible to realize a wide viewing angle in gradation display and high display quality.

According to the thin film transistor type liquid crystal display device of the second aspect, since the conductive thin film is provided on the pixel electrode and is adjusted to have a predetermined film thickness and area, the thin film transistor type liquid crystal display device. The electro-optical characteristics of are obtained by averaging the optical characteristics of each divided liquid crystal molecule array area, and a wide high-contrast ratio visual range with symmetry in a predetermined viewing angle direction is obtained, and at a specific viewing angle and voltage. It is possible to avoid the gradation reversal phenomenon, and to realize a natural image display that does not depend on the viewing angle and the voltage, and realize a wide viewing angle of gradation display and high display quality.

According to the thin film transistor type liquid crystal display device of the third aspect, the conductive thin film is provided on the counter electrode and is adjusted to have a predetermined film thickness and area. Therefore, the thin film transistor type liquid crystal display device. The electro-optical characteristics of are obtained by averaging the optical characteristics of each divided liquid crystal molecule array area, and a wide high-contrast ratio visual range with symmetry in a predetermined viewing angle direction is obtained, and at a specific viewing angle and voltage. It is possible to avoid the gradation reversal phenomenon, and to realize a natural image display that does not depend on the viewing angle and the voltage, and realize a wide viewing angle of gradation display and high display quality.

According to the thin-film transistor type liquid crystal display device of the fourth aspect, at least one of the film thickness and the area of the conductive thin film is made different between two adjacent pixels. Produce an effect.

According to the thin film transistor type liquid crystal display device of the fifth aspect, the conductive thin film is provided in a predetermined region on the pixel electrode and is simultaneously formed on the counter electrode in a region other than the predetermined region. The electro-optical characteristics of the thin film transistor type liquid crystal display device are obtained by averaging the optical characteristics of the respective divided liquid crystal molecule alignment regions, and a wide high contrast ratio visual range having symmetry in a predetermined viewing angle direction can be obtained, Gradient inversion phenomenon at viewing angle and voltage is avoided,
It is possible to realize a natural image display that does not depend on the viewing angle and the voltage, and realize a wide viewing angle of gradation display and high display quality.

According to the thin film transistor type liquid crystal display device of the sixth aspect, the conductive thin film is formed on at least one of the pixel electrode and the counter electrode, and the conductive thin film is 0.1 or less.
Since it is formed to have a film thickness of not less than μm, the same effects as those of the second and third aspects can be obtained.

[Brief description of drawings]

FIG. 1 is a plan view of a TFT substrate of a thin film transistor type liquid crystal display device according to a first embodiment of the present invention.

2 is a cross-sectional view of one pixel portion of the thin film transistor type liquid crystal display device of FIG.

FIG. 3 is an alignment regulation state diagram of liquid crystal molecules sandwiched between a TFT substrate and a counter electrode substrate of the thin film transistor type liquid crystal display device shown in FIGS. 1 and 2.

4 is a liquid crystal alignment cross-sectional view of one pixel portion of the thin film transistor type liquid crystal display device shown in FIGS. 1 and 2. FIG.

FIG. 5 is a sectional view of a pixel portion of a thin film transistor type liquid crystal display device according to a second embodiment of the present invention.

FIG. 6 is a sectional view of a pixel portion of a thin film transistor type liquid crystal display device according to a third embodiment of the present invention.

FIG. 7 is a contrast ratio dependence characteristic diagram with respect to an incident angle in a vertical viewing angle direction of the thin film transistor type liquid crystal display device according to the first example of the present invention.

FIG. 8 is a transmittance-dependent characteristic diagram of 8-gradation display with respect to an incident angle in a vertical viewing angle direction of the thin film transistor type liquid crystal display device according to the first example of the present invention.

FIG. 9 is a partial cross-sectional view of a channel portion of a thin film transistor in a conventional thin film transistor type liquid crystal display device.

FIG. 10 is a partial cross-sectional view of a conventional thin film transistor type liquid crystal display device.

FIG. 11 shows T of a conventional thin film transistor type liquid crystal display device.
It is an alignment control state figure of the liquid crystal molecule pinched between the FT board and the counter electrode board.

FIG. 12 is a contrast ratio dependence characteristic diagram with respect to an incident angle in a vertical viewing angle direction of a conventional thin film transistor type liquid crystal display device.

FIG. 13 is a transmittance-dependent characteristic diagram of 8-gradation display in the vertical viewing angle direction in the conventional thin film transistor type liquid crystal display device.

FIG. 14 is an applied voltage-transmittance characteristic diagram in a front view angle direction in a conventional thin film transistor type liquid crystal display device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Pixel electrode, 2 ... Gate electrode (TFT part), 3 ... Source electrode, 4 ... Drain electrode (TFT part), 5 ... Gate electrode (Pre-stage gate part), 6 ... Drain electrode (Pre-stage gate part), 7A, 7B ... Glass substrate, 8 ... First insulating film, 9 ... Gate oxide film, 10 ... Semiconductor layer, 11 ... Second
Insulating film, 12 ... Ohmic contact layer, 13 ... Conductive thin film, 14 ... Black matrix layer, 15 ... Color filter layer, 16 ... Protective film, 17 ... Counter electrode, 18A, 18B ...
Alignment film, 19A, 19B ... Polarizing plate, 20 ... Liquid crystal, 21 ... Contact window (TFT part), 22 ... Contact window (previous gate part).

Claims (6)

[Claims] 1. A pixel electrode substrate in which a thin film transistor is formed at an intersection of a gate electrode and a source electrode arranged in a matrix and a pixel electrode is formed in a state of being connected to a drain electrode of the thin film transistor, and a common counter electrode. And a counter electrode substrate disposed so as to face the pixel electrode substrate with a liquid crystal sandwiched therebetween, and at least one of the pixel electrode substrate and the counter electrode substrate has a different height in an effective display region of a pixel unit. A thin film transistor type liquid crystal display device characterized in that a pixel electrode or a counter electrode having is formed. 2. The thin film transistor type liquid crystal display device according to claim 1, wherein a conductive thin film is provided on the pixel electrode, and the conductive thin film is adjusted to have a predetermined film thickness and area. 3. The thin film transistor type liquid crystal display device according to claim 1, wherein a conductive thin film is provided on the counter electrode, and the conductive thin film is adjusted to have a predetermined thickness and area. 4. The thin film transistor type liquid crystal display device according to claim 2, wherein at least one of the film thickness and the area of the conductive thin film is different between two adjacent pixels. 5. The thin film transistor type according to claim 1, wherein the conductive thin film is provided in a predetermined region on the pixel electrode and is formed on the counter electrode in a region other than the predetermined region. Liquid crystal display device. 6. A conductive thin film is formed on at least one of the pixel electrode and the counter electrode, and the conductive thin film is formed.
2. The thin film transistor type liquid crystal display device according to claim 1, wherein the thin film transistor type liquid crystal display device is formed with a film thickness of 0.1 μm or more.