JPH07270822A - Liquid crystal display element - Google Patents

Abstract

PURPOSE:To attain the expanding of a visual angle while securing brightness of a display by dividing each pixel part into plural areas, making thicknesses of liquid crystal layer different each other and making products between the refractive index anisotropy and thicknesses of liquid crystal layer and threshold value voltages in areas different. CONSTITUTION:In a twisted nematic type active matrix liquid crystal display element in which the layer of liquid crystal 15 is provided in between one pair of transparent substrates 1, 2 on whose counter faces electrodes are respectively provided, each pixel electrode 3 of the lower substrate 1 is made to be a step shaped electrode in which surface heights of areas w1 to w3 having respectively a width being about one third of the electrode width W are made different each other and thicknesses d1 to d3 of liquid crystal layer of respective pixel parts are made different each other. Consequently, products DELTAnd between the refractive index anisotropy DELTAn of the liquid crystal and thicknesses of liquid crystal layer (d) and threshold value voltages Vth are different in respective areas w1 to w3. Thus, the average transmissivity in the whole of pixel parts can be enhanced by allowing DELTAnds of certain areas to be values with which high transmissivity can he obtained and the rise-up oriented states of liquid crystal at the time of impressing a voltage can be made different in every area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dot matrix liquid crystal display device.

[0002]

2. Description of the Related Art In a dot matrix liquid crystal display device,
There are an active matrix liquid crystal display element and a simple matrix liquid crystal display element, and these liquid crystal display elements are generally TN (twisted nematic).
Type or STN (super twisted nematic) type is used.

In the above-mentioned TN type and STN type liquid crystal display elements, nematic liquid crystal having a positive dielectric anisotropy is sealed between a pair of transparent substrates on which transparent electrodes are formed and on which an alignment film is provided. The molecules are twist-aligned between both substrates, and the twist angle of liquid crystal molecules between both substrates is about 90 ° for TN type and 180-2 for STN type.
It is set to 70 °.

By the way, the liquid crystal display element in which the liquid crystal molecules such as the TN type and the STN type are twist-aligned has a viewing angle dependence in its display characteristics, and the display contrast varies depending on the viewing angle (the viewing angle of the display). Looks like

This viewing angle dependency is due to the Δnd of the liquid crystal display element.
It is determined by the value of (product of refractive index anisotropy Δn of liquid crystal and liquid crystal layer thickness d), and within a general range of Δnd values, the smaller Δnd is, the better the angle range (below , Viewing angle) becomes wider.

[0006]

However, the conventional liquid crystal display element has a problem that the display becomes darker when Δnd is reduced and the viewing angle is widened. this is,
This is because the light transmittance in the on (bright display) state in the liquid crystal display element in which the liquid crystal molecules are twist-aligned differs depending on the value of Δnd, and in the general range of Δnd values, the larger Δnd is, the more the light is transmitted. The transmittance is high, and the transmittance is low when Δnd is small.

For this reason, in the conventional liquid crystal display element, if Δnd is set small with emphasis on the viewing angle, the transmittance is lowered and the display becomes dark, and conversely, Δnd is emphasized with emphasis on the brightness of the display. If the value of is set to a large value, the viewing angle becomes narrow. An object of the present invention is to provide a liquid crystal display element capable of widening a viewing angle while ensuring sufficient display brightness.

[0008]

DISCLOSURE OF THE INVENTION The present invention provides a dot matrix liquid crystal display device in which a liquid crystal is provided between a pair of substrates each having electrodes on opposite surfaces, and molecules of the liquid crystal are twist-aligned. Is divided into a plurality of regions, and the liquid crystal layer thicknesses of the respective regions are made different from each other. It is characterized in that it is different for each area of the section.

In order to make the liquid crystal layer thickness in each region of the pixel portion different from each other, the electrodes on at least one substrate of the pair of substrates are provided on the surface of the portion corresponding to each region of the pixel portion. It is only necessary to use electrodes having steps with different heights, and as a means thereof, for example, the film thicknesses of the portions corresponding to the respective regions of the pixel portion on at least one of the pair of substrates are mutually different. Different base films may be provided and the electrodes may be formed thereon.

[0010]

In the liquid crystal display device of the present invention, since the Δnd values of the regions of the pixel portion are different, the transmittances of these regions are different from each other. In this liquid crystal display element, since one pixel portion is divided into a plurality of regions having different transmittances, Δn of at least one of the regions is divided.
By setting d to a value that allows high transmittance, the average transmittance of the entire pixel portion can be increased.

Moreover, in this liquid crystal display device, the threshold voltage Vth of each region is made different by making the liquid crystal layer thickness of each region different from each other, so that a voltage is applied between the electrodes of the pixel portion. The rising alignment state of the liquid crystal molecules when applied is made different for each of the regions, so that the apparent viewing angle of the entire pixel portion when applying a voltage can be widened. Therefore, according to the liquid crystal display element of the present invention, it is possible to widen the viewing angle while ensuring sufficient display brightness.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a part of a liquid crystal display device showing a first embodiment of the present invention. The liquid crystal display element of this embodiment is a TN type active matrix liquid crystal display element, and is one of a pair of transparent substrates (for example, glass substrates) 1 and 2 facing each other with a layer of the liquid crystal 15 interposed therebetween, which is the lower side in the figure. A substrate (hereinafter referred to as a lower substrate) 1 has a plurality of transparent pixel electrodes 3 arranged in a matrix in a row direction and a column direction, and a plurality of switching elements 4 respectively corresponding to the pixel electrodes 3. It is provided, and the alignment film 11 is provided thereon.

The switching element 4 is, for example, a TFT
(Thin film transistor), and this TFT 4 is the substrate 1
A gate electrode 5 formed on the gate electrode 5; a gate insulating film 6 covering the gate electrode 5; and a-Si (amorphous silicon) or the like 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 semiconductor film 7. The gate insulating film 6
Is a transparent film made of Si N (silicon nitride) or the like,
The gate insulating film 6 is formed on almost the entire surface of the substrate 1.

Although not shown, the lower substrate 1 is
A gate line (address line) for supplying a gate signal to the gate electrode 5 of the TFT 4 and a data line for supplying a data signal according to image data to the drain electrode 9 of the TFT 4 are wired.

The gate line is formed on the substrate 1 by the T
The gate line is formed integrally with the gate electrode 5 of the FT 4, and the gate line except the terminal portion thereof has the gate insulating film 6 formed thereon.
Is covered with. The data line is formed on the gate insulating film 6, and the data line is connected to the drain electrode 9 of the TFT 4.

On the gate insulating film 6, a base film 10 made of a transparent insulating film such as SiN is provided in the area where each pixel electrode 3 is formed. It is formed over the gate insulating film 6 from 10 and is connected to the source electrode 8 of the corresponding TFT 4 at one end thereof.

The base film 10 is provided from one end of the pixel electrode 3 (the end portion on the TFT 4 side in this embodiment) to a width of about ⅔ of the pixel electrode width W. Further, the base film 10 is provided. Part of almost half width, that is, pixel electrode 3
The portion extending from one end to approximately 1/3 of the pixel electrode width W is formed thicker than the film thickness of the portion corresponding to the central portion of the pixel electrode 3.

Although the underlayer film 10 is shown as an integrated film in the figure, the underlayer film 10 has a width of about ⅔ of the pixel electrode width W from one end of the pixel electrode 3 on the gate insulating film 6. A first insulating film formed over the first insulating film, and a second insulating film formed on the first insulating film from one end of the pixel electrode 3 to a width of about 1/3 of the pixel electrode width W. ing.

The pixel electrode 3 is formed to have a uniform film thickness over the base film 10 and the gate insulating film 6. Therefore, the pixel electrode 3 has a width of about 1/3 each. The regions w1, w2, and w3 of the electrode have stepwise steps having different surface heights.

Further, the alignment film 11 provided on the pixel electrode 3 is also formed to have a uniform film thickness over the entire area thereof. Therefore, the film surface of the alignment film 11 also has the step difference of the pixel electrode 3. It has a step-like step according to.

On the other hand, in FIG. 1, an upper substrate (hereinafter referred to as an upper substrate) 2 is provided with color filters of a plurality of colors, for example, a red filter 12R corresponding to the respective pixel electrodes 3 on the lower substrate 1. , Green filters 12G and blue filters 12B are alternately formed, and
On these color filters 12R, 12G, 12B,
A transparent counter electrode 13 facing all the pixel electrodes 3 of the lower substrate 1 is provided, and an alignment film 14 is provided thereon.

In this embodiment, the color filters 12R, 12G and 12B for the respective colors are formed to have substantially the same thickness, and the counter electrode 13 and the alignment film 14 formed thereon are formed to have uniform thicknesses. Therefore, the film surface of the alignment film 14 on the upper substrate 2 side is substantially flat.

Although not shown, the lower substrate 1 and the upper substrate 2 are bonded to each other via a frame-shaped sealing material at the outer peripheral edge thereof, and the liquid crystal 15 is sealed between the substrates 1 and 2. The area surrounded by the material is filled.

The liquid crystal 15 is a nematic liquid crystal having a positive dielectric anisotropy, and the molecules of the liquid crystal 15 are formed on both substrates 1.
Orientation directions on the substrates 1 and 2 are regulated by the alignment films 11 and 14 provided on the substrate 2, and the substrates 1 and 2 are twist-aligned at a twist angle of about 90 °. The alignment films 11 and 14 are horizontal alignment films made of polyimide or the like, and the film surfaces thereof are subjected to an alignment treatment by rubbing.

Polarizing plates 16 and 17 are arranged on the outer surface of the lower substrate 1 and the outer surface of the upper substrate 2, respectively.
The liquid crystal display element of this example has a positive display when no voltage is applied, that is, when the liquid crystal molecules are in the twist alignment state, the display is bright, and when the voltage is applied, the display is dark and the display is dark. The polarizing plates 16 and 17 are of a type, and their polarization axes (transmission axis or absorption axis)
Are arranged substantially orthogonal to each other.

In the liquid crystal display device of this embodiment, the surface of each pixel electrode 3 of the lower substrate 1 is covered with the regions w1, w2, w3 each having a width of about ⅓ of the pixel electrode width W as described above. Since the electrodes having step-like steps of different heights are used, the liquid crystal layer thickness (alignment film of both substrates 1 and 2) of each pixel portion (the portion corresponding to each pixel electrode 3) of this liquid crystal display element The intervals d1, d2, d3 between the 11 and 14 planes are different for each of the three regions w1, w2, w3. Therefore, this liquid crystal display device has a value of Δnd and a threshold voltage Vth. Are each of the areas w1, w2, w3 of the pixel section.
Each is different.

Here, Δnd of the liquid crystal display element is the product of the refractive index anisotropy Δn of the liquid crystal and the liquid crystal layer thickness d, and in the above liquid crystal display element, the liquid crystal of each region w1, w2, w3 of the pixel portion is Since the layer thicknesses d1, d2, d3 are d1 <d2 <d3, the values of .DELTA.nd of these regions w1, w2, w3,
Δnd1, Δnd2, and Δnd3 are Δnd1 <Δnd2
<Δnd3.

FIG. 2 shows the voltage-transmittance characteristic of the TN type liquid crystal display element. This characteristic shifts to the left in the figure as the liquid crystal layer thickness d is reduced, As the thickness d increases, it shifts to the right in the figure, so the threshold voltage Vth1 of the region w1 of the pixel portion is increased.
Then, the threshold voltage Vth2 of the region w2 and the threshold voltage Vth3 of the region w3 are Vth1 <Vth2 <Vth3.
In Fig. 2, V50% is the maximum transmittance of 100%.
Is the applied voltage value at which the transmittance becomes 50%.

In the liquid crystal display element, since the values of Δnd of the respective regions w1, w2, w3 of the pixel portion are different, the transmittance and the viewing angle of these respective regions w1, w2, w3 are different from each other.

3 and 4 show the relationship between Δnd and the transmittance and the relationship between Δnd and the viewing angle of the TN type liquid crystal display element. Here, the value of Δnd is 0.26 μm to
The results obtained by examining the transmittance and the viewing angle by applying a voltage at which the maximum transmittance is obtained while changing the thickness in the range of 0.48 μm are shown.

The transmittance shown in FIG. 3 is the transmittance in the normal direction of the liquid crystal display element, and the viewing angle (θ) shown in FIG. 4 is in the viewing angle range with respect to the normal line h of the liquid crystal display element. It is the sum of the viewing angle θ1 in the smallest direction and the viewing angle θ2 in the direction in which the viewing angle range is largest (θ = θ1 + θ2).

As shown in FIGS. 3 and 4, the TN
The transmittance and viewing angle of the liquid crystal display device vary depending on the value of Δnd. In the range of Δnd of 0.26 μm to 0.48 μm, the transmittance increases as Δnd increases, and conversely, Δnd increases. Is larger, the viewing angle is narrower.

In the above liquid crystal display device, one pixel portion is divided into three regions w1, w2 and w3 having different transmissivities, so that at least one of the regions w1, w2 and w3 is Δnd. Can be set to a value at which a high transmittance is obtained, and the average transmittance in the entire pixel portion can be increased.

As a specific example of the transmittance of each of the regions w1, w2, w3, for example, the refractive index anisotropy Δn of the liquid crystal 15 is Δn.
And the liquid crystal layer thickness d1 of each region w1, w2, w3 of the pixel portion,
When d2 and d3 are .DELTA.n = 0.09 d1 = 4.38 .mu.m d2 = 4.75 .mu.m d3 = 5.15 .mu.m, the .DELTA.nd values .DELTA.nd1, .DELTA.nd2 and .DELTA.nd3 of the respective regions w1, w2 and w3 are .DELTA.nd1 = 0.3942 μm Δnd2 = 0.4275 μm Δnd3 = 0.4635 μm. The liquid crystal 15 has a m.p. p (solid-liquid crystal phase transition point) is -25 ° C or lower, c. p (liquid crystal phase-isotropic phase transition point) is 85 ° C.

In this way, Δn of each area w1, w2, w3
The transmittances of the regions w1, w2, w3 when the values of d Δnd1, Δnd2, Δnd3 are selected are, as shown in FIG. 3, about 29% for the region w1, about 31% for the region w2, and about 3% for the region w3.
2%.

In this example, the regions w1, w2, and
Of w3, the transmittance of the region w3 is the highest at about 32%, but the transmittances of the other two regions w1 and w2 are considerably high at about 29% in the region w1 and about 31% in the region w2. Since the average transmittance of the entire pixel portion is sufficiently high, a very bright display can be obtained.

On the other hand, Δn of each of the above regions w1, w2, w3
The respective regions w1, w2, when the values of d Δnd1, Δnd2, Δnd3 are values that can obtain high transmittance as described above.
The viewing angle (θ) of w3 is about 6 in the area w1 as shown in FIG.
7.5 °, about 64.5 ° in area w2, about 62 in area w3
°, and therefore Δn for each region w1, w2, w3
The viewing angle according to the value of d is relatively narrow.

However, in the above liquid crystal display device, the liquid crystal layer thicknesses d1, d2 and d3 of the respective regions w1, w2 and w3 are set.
By making each region different from each other, each region w1, w2,
Since the threshold voltage Vth of w3 is different from each other,
The rising alignment state of liquid crystal molecules when a voltage is applied between the electrodes of the pixel section (between the pixel electrode 3 and the counter electrode 13) is made different for each region w1, w2, w3, and the pixel section at the time of voltage application. It is possible to widen the apparent viewing angle as a whole.

The difference between the threshold voltages Vth1, Vth2 and Vth3 of the respective regions w1, w2 and w3 will be described. For example, the liquid crystal 15 is the above-mentioned liquid crystal (mp = -25 ° C. or less,
c. p = 85 ° C., Δn = 0.09), and the liquid crystal layer thicknesses d1, d2, d3 of the respective regions w1, w2, w3 are, as described above, d1 = 4.38 μm, d2 = 4.75 μm.
When m, d3 = 5.15 μm, V50 shown in FIG.
The value of% (value at 25 ° C.) is V50% = 2.07 in the region w1 (d1 = 4.38 μm).
In the V region w2 (d2 = 4.75 µm), V50% = 2.12
In the V region w3 (d3 = 5.15 µm), V50% = 2.16
V, and each of the regions w1, w2, w3 has a threshold voltage difference corresponding to the difference in the value of V50%.

The voltage applied between the electrodes of the pixel portion is uniformly applied to all the regions w1, w2 and w3, but the threshold voltage Vth1 of each of the regions w1, w2 and w3 is Since Vth2 and Vth3 are different from each other, the rising alignment state of liquid crystal molecules when a voltage is applied is
Since w2 and w3 are different for each region, the viewing angle of bright display displayed by the rising orientation of liquid crystal molecules is different for each region w.
Different for 1, w2 and w3.

Therefore, the apparent viewing angle of the entire pixel portion when a voltage is applied to the liquid crystal display element is a range including all the viewing angles of the bright display in each of the regions w1, w2, w3. Even when the display is viewed from a direction outside the viewing angle of one or two bright displays among the three regions w1, w2, and w3, the observation direction may be within the viewing angles of the other bright displays. For example, the bright display is observed as a bright pixel.

Therefore, according to the above liquid crystal display device,
It is possible to widen the viewing angle while ensuring sufficient display brightness. In the above embodiment, each region w of the pixel portion is
Value of Δnd of 1, w2, w3 Δnd1, Δnd2, Δn
d3 is set to a value that can obtain a high transmittance, and the viewing angle is secured by the difference in the threshold voltage Vth of the regions w1, w2, w3. Of the regions w1, w2, w3, In either case, the value of Δnd may be set to a value at which a wide viewing angle can be obtained (Δnd = 0.26 to 0.36 μm). In this case, the brightness of the display is slightly lower than that in the above embodiment. However, in addition to the width of the viewing angle when the voltage is applied due to the difference in the threshold voltage Vth described above, the viewing angle determined by the value of Δnd can also be widened.

Further, in the above embodiment, the pixel portion is divided into three regions w1, w2 and w3, but the number of regions may be any number of 2 or more. For example, the pixel portion may be arranged in the row direction and the column direction. It may be divided into four or more areas,
Further, the area ratio of each region may be arbitrary.

Further, the liquid crystal layer thicknesses d1 and d in each region of the pixel portion
2 and d3 do not have to be successively increased as d1 <d2 <d3 as in the above embodiment, as long as the liquid crystal layer thickness of each region is different from each other, and the liquid crystal layer thickness of every other region is You may make it the same layer thickness.

FIG. 5 is a sectional view of a part of a liquid crystal display device showing a second embodiment of the present invention. In the liquid crystal display device of this embodiment, each pixel portion is divided into two regions w11 and w12. The liquid crystal layer thicknesses d11, d12 of the respective regions w11, w12 are made different from each other, and the value of the liquid crystal 15Δnd and the threshold voltage Vth are made different for each of the regions w11, w12 of the pixel section. In this embodiment, the pixel portion is divided into two regions w11, w
Except for the point divided into twelve, the other structure is the same as that of the first embodiment described above, and therefore the duplicated description is given the same symbols in the drawings and omitted.

Also in the liquid crystal display element of this embodiment, the values Δnd11 and Δnd of Δnd of the respective regions w11 and w12 of the pixel portion.
Since 12 are different, the transmittances of these regions w11 and w12 are different from each other.

In this liquid crystal display element, since one pixel portion is divided into two regions w11 and w12 having different transmissivities, Δnd of at least one of the regions w11 and w12 is high. The average transmittance of the entire pixel portion can be increased by setting the value of

As a specific example of the transmittance of each of the regions w11 and w12, for example, the liquid crystal 15 has the same liquid crystal as the first embodiment (mp = −25 ° C. or less, cp = 85 ° C., Δn =
0.09 liquid crystal), and the liquid crystal layer thicknesses d11 and d12 in the respective regions w11 and w12 are set to the regions w1 and w in the first embodiment.
When the liquid crystal layer thicknesses d1 and d3 of 3 are the same (d11 = 4.
38 μm, d12 = 5.15 μm), each region w1
The Δnd values Δnd11 and Δnd12 of 1 and w12 are Δnd11 = 0.3942 μm Δnd12 = 0.4635 μm, and thus the Δnd value Δn of each of the regions w11 and w12.
The transmittances of the regions w11 and w12 when d11 and Δnd12 are selected are approximately 29% in the region w11 and approximately 32% in the region w12.

In this example, the transmittance of each of the regions w11 and w12 is as high as about 32% in the region w12 and about 29% in the region w11, so that the average transmittance of the entire pixel portion is sufficiently high.
You can get a very bright display.

Also in this liquid crystal display element, the liquid crystal layer thicknesses d11 and d12 of the respective regions w11 and w12 are made different from each other, so that the threshold voltage V of these regions w11 and w12 is set.
Since th is different from each other, the electrodes 3 and 13 of the pixel portion are
The rising alignment state of liquid crystal molecules when a voltage is applied between the regions w11 and w12 can be made different to widen the apparent viewing angle of the entire pixel portion when a voltage is applied.

Threshold voltage Vth of each of the above regions w11 and w12
Explaining the difference between 11 and Vth12, for example, the liquid crystal 15 is the above-mentioned liquid crystal with Δn = 0.09, and the respective regions w11 and w
As described above, the liquid crystal layer thicknesses d11 and d12 of 12 are d11 = 4.
When 38 μm and d12 = 5.15 μm, the value of V50% (value at 25 ° C.) shown in FIG. 2 is V50% = 2.07 in the region w11 (d11 = 4.38 μm).
In the V region w12 (d12 = 5.15 μm), V50% = 2.16
V 2 and each of the regions w11 and w12 has a threshold voltage difference corresponding to the difference in the value of V50%.

The voltage applied between the electrodes of the pixel portion is uniformly applied to all of the regions w11 and w12, but the threshold voltages Vth11 and Vth of these regions w11 and w12, respectively.
Since th12 is different from each other, the rising alignment state of liquid crystal molecules when a voltage is applied is different for each region w11, w12,
Therefore, the viewing angle of the bright display displayed by the rising orientation of the liquid crystal molecules is different for each of the regions w11 and w12.

Therefore, the apparent viewing angle of the entire pixel portion when a voltage is applied to the liquid crystal display element is a range including all the viewing angles of the bright display in the regions w11 and w12, for example, 2 One of the bright indications of two areas w11 and w12
Even when viewing the display from the direction outside the viewing angle of the two bright displays,
If the observation direction is within the viewing angle of another bright display, the bright display is observed as a bright pixel.

Therefore, also in the liquid crystal display element of the second embodiment, it is possible to widen the viewing angle while ensuring sufficient display brightness. In the second embodiment, the value Δnd1 of each region w11 and w12 of the pixel portion Δnd1
The values of 1 and Δnd12 are set to values that can obtain a high transmittance, and the viewing angle is secured by the difference in the threshold voltage Vth between the regions w11 and w12, but either of the regions w11 and w12 is The value of Δnd may be set to a value (Δnd = 0.26 to 0.36 μm) that allows a wide viewing angle to be obtained. In this case, the brightness of the display is slightly lower than that in the above-mentioned embodiment. In addition to the wide viewing angle when a voltage is applied due to the difference in the threshold voltage Vth described above, the viewing angle determined by the value of Δnd can also be widened.

Furthermore, in the first and second embodiments, the pixel electrode 3 on the lower substrate 1 is an electrode having a step difference in order to make the liquid crystal layer thickness of each region of the pixel portion different from each other. On the contrary, even if the pixel electrode facing portion of the counter electrode 13 of the upper substrate 2 is made into a stepped electrode in which the surface heights of the portions corresponding to the respective regions of the pixel portion are different from each other,
The liquid crystal layer thickness of each region of the pixel unit may be different from each other.

The liquid crystal display elements of the first and second embodiments are active matrix elements using TFTs as switching elements. The present invention is, for example, MIM.
The present invention can be applied to an active matrix liquid crystal display element having a switching element as a switching element and a simple matrix liquid crystal display element.
It can also be applied to a TN type dot matrix liquid crystal display device.

[0057]

According to the present invention, in a dot matrix liquid crystal display element in which liquid crystal molecules are twist-aligned, each pixel portion is divided into a plurality of regions and the liquid crystal layer thickness of each region is made different from each other to obtain a refractive index of liquid crystal. Since the value of the product Δnd of the anisotropy Δn and the thickness d of the liquid crystal layer and the threshold voltage Vth are made different for each region of the pixel portion, sufficient display brightness is ensured. However, the viewing angle can be widened.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a liquid crystal display element showing a first embodiment of the present invention.

2 is a voltage-transmittance characteristic of a TN type liquid crystal display device.

FIG. 3 is a diagram showing a relationship between Δnd and transmittance of a TN type liquid crystal display element.

FIG. 4 is a view showing a relationship between Δnd and a viewing angle of a TN type liquid crystal display element.

FIG. 5 is a partial cross-sectional view of a liquid crystal display element showing a second embodiment of the present invention.

[Explanation of symbols]

 1, 2 ... Substrate 3 ... Pixel electrode 4 ... Switching element (TFT) 10 ... Base film 11 ... Alignment film 12R, 12G, 12C ... Color filter 13 ... Counter electrode 14 ... Alignment film 15 ... Liquid crystal 17, 18 ... Polarizing plate d1 , D2, d3, d11, d12 ... Liquid crystal layer thickness

Claims (3)

[Claims] 1. A dot-matrix liquid crystal display element in which liquid crystal is provided between a pair of substrates each having electrodes on opposite surfaces, and molecules of the liquid crystal are twist-aligned, and each pixel portion is divided into a plurality of regions. The liquid crystal layer thickness of each region is made different from each other, and the value of the product Δnd of the refractive index anisotropy Δn of the liquid crystal and the liquid crystal layer thickness d and the threshold voltage Vth are set for each region of the pixel portion. A liquid crystal display device characterized by being different. 2. An electrode on at least one of the pair of substrates is an electrode having a step in which surface heights of portions corresponding to respective regions of the pixel portion are different from each other. The liquid crystal display element according to claim 1. 3. A base film having different film thicknesses in portions corresponding to respective regions of the pixel portion is provided on at least one of the pair of substrates, and electrodes are formed thereon. Item 3. The liquid crystal display device according to item 1 or 2.