JP2010210733A - Liquid crystal display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display panel of an electric field controlled birefringence ECB mode suppressing light leakage due to influence between adjacent pixels without expanding a black matrix. <P>SOLUTION: In the liquid crystal display panel 10A of the ECB mode having a first substrate (an array substrate AR) and a second substrate (a color filter substrate CF) disposed opposite to each other sandwiching a liquid crystal layer LC and having a pixel electrode 19 formed for every sub pixel SP and driving the liquid crystal layer LC in a driving region of the first substrate, a projecting part B2 protruding to the liquid crystal layer LC side along the longitudinal direction of the sub pixel SP is formed between the sub pixels SP. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a field effect birefringence (ECB) mode liquid crystal display panel, and more particularly to an ECB mode liquid crystal display panel with reduced light leakage at the periphery of a drive region.

A liquid crystal display device has characteristics of light weight, thinness, and low power consumption as compared with a CRT (cathode ray tube), and thus is used in many electronic devices for display. The liquid crystal display device displays an image by changing the direction of liquid crystal molecules aligned in a predetermined direction by an electric field and changing the amount of light transmitted through the liquid crystal layer. This includes both a reflection type in which external light enters the liquid crystal layer, and transmits again through the liquid crystal layer with a reflector, and a transmission type in which light from the backlight device transmits through the liquid crystal layer. There is a transflective type.

As the transflective type, those of TN (Twisted Nematic) mode, STN (Supertwisted Nematic) mode, ECB mode, etc. are known. The ECB mode liquid crystal display panel uses birefringence using a nematic liquid crystal having positive dielectric anisotropy, and the rubbing directions between a pair of substrates differ from each other by 180 °, and the applied voltage to the liquid crystal molecules. Is a longitudinal electric field type in which the retardation is changed by controlling the transmission and non-transmission of light by combination with a retardation film. In this ECB mode liquid crystal display panel, both luminance and chromaticity are likely to fluctuate due to the influence of the thickness of the liquid crystal layer and film variation, and there is a weak point that the contrast becomes low, but both reflective and transmissive displays are possible. , Has excellent visibility outdoors. Also,
An ECB mode liquid crystal display element can obtain colored light by using the birefringence action of the liquid crystal layer and the polarization action of at least one polarizing plate without using a color filter. Power consumption can also be reduced. For this reason, the ECB mode is widely used in mobile devices such as mobile phone devices.

However, it has been observed that when an ECB mode liquid crystal display panel is used, light leakage occurs at one of the boundaries between the drive area display and the non-drive area. According to experiments, light leakage occurred at the boundary between the driving area and the non-driving area opposite to the rubbing direction of the array substrate. The drive area is an area in which an image is displayed by applying an electric field to liquid crystal molecules. As shown in Patent Document 1, it was estimated that this light leakage occurred for the following reason. That is, when an electric field is applied to the drive region, the liquid crystal tends to rise from the horizontal direction to the vertical direction. The equipotential lines at this time are substantially parallel to the array substrate in the driving region, but since no electric field is applied in the non-driving region, the equipotential lines are output from the driving region to the non-driving region. Will suddenly decline. At this time, at the boundary between the driving region and the non-driving region side in the same direction as the rubbing direction of the array substrate, the rising direction of the liquid crystal molecules and the rising direction of the liquid crystal molecules in the driving region are the same. Disturbance of the alignment of the liquid crystal molecules does not occur at the boundary between the two.

However, at the boundary between the driving region and the non-driving region opposite to the rubbing direction of the array substrate, it is strongly governed by the influence of the equipotential lines in the rising direction of the liquid crystal molecules on the non-driving region side dropping sharply. In other words, the rising directions of the liquid crystal molecules in the driving region are opposite to each other. That is, when an electric field is applied, the rise restriction due to the influence of the electric field is stronger than the rise direction restriction caused by the pretilt angle caused by the alignment film (hereinafter referred to as rubbing treatment). For this reason, it was considered that the liquid crystal molecule orientation was disturbed in an unexpected direction near the boundary between the driving region and the non-driving region, and the light leakage occurred. Therefore, in the invention disclosed in Patent Document 1 below, a dummy pixel that applies an electric field that prevents an equipotential line from drastically dropping in a non-driving region is provided.

JP 2007-264233 A

However, in the ECB mode liquid crystal display panel, the location where liquid crystal molecules are unexpectedly aligned and light leaks is not limited to the boundary between the drive region and the non-drive region. In the liquid crystal display panel, sub pixels are partitioned in a matrix by scanning lines and signal lines, and a liquid crystal layer is driven for each sub pixel by a pixel electrode formed in each of the sub pixels. Therefore, the adjacent subpixels may have different electric potentials, and the alignment of liquid crystal molecules may be different. For this reason, under the influence of adjacent sub-pixels, the liquid crystal molecules are unexpectedly aligned near the boundary of the sub-pixels in the display region, and light cannot leak following screen switching. FIG. 9 is a sectional view showing this state. A pixel electrode 19 and a counter electrode 25 for applying an electric field to the liquid crystal layer LC are formed in the left and right subpixels SP and SP, respectively. When the electric field applied to the left sub-pixel changes, the response of the liquid crystal molecules in the A portion on the right sub-pixel SP side is delayed by the electric lines of force of the right sub-pixel SP, causing light leakage.

In particular, in a color liquid crystal display panel, R (red), G (green), and B (blue) sub-pixels are aligned in the scanning line direction, and a color of one pixel is displayed by a mixed color of R, G, and B. Since voltages are often applied to different gradations in adjacent pixels in the scanning line direction, light leakage tends to occur along the longitudinal direction of the sub-pixels, that is, along the signal lines. Moreover, the light leakage is more noticeable in the normally white mode than in the normally black mode. Furthermore, if the response speed of the liquid crystal display panel is lowered to prevent flicker (flicker), light leakage due to failure to follow screen switching becomes conspicuous. Although light leakage can be prevented by widening the black matrix of the color filter substrate formed between the sub-pixels, this method is not preferable because the aperture ratio is reduced.

The present invention has been made to solve the above-described problems of the prior art, and an ECB mode in which light leakage due to the influence of adjacent pixels is prevented along the longitudinal direction of the sub-pixels without expanding the black matrix. An object of the present invention is to provide a liquid crystal display panel.

In order to achieve the above object, a liquid crystal display panel according to the present invention includes a first substrate and a second substrate that are opposed to each other with a liquid crystal layer interposed therebetween, and a driving region of the first substrate is provided for each sub-pixel. An ECB mode liquid crystal display panel having a pixel electrode that is formed and that drives the liquid crystal layer, and a protrusion projecting toward the liquid crystal layer along the longitudinal direction of the sub pixel is formed between the sub pixels. It is characterized by.

In an ECB mode liquid crystal display panel, the alignment of liquid crystal molecules may fall in an unexpected direction due to the influence of adjacent sub-pixels, and light may leak without being able to follow the screen switching speed. In particular, this light leakage is conspicuous when the response speed of the liquid crystal is reduced due to flicker countermeasures or the like. In the ECB mode liquid crystal display panel of the present invention, the direction of the rubbing treatment of the alignment film changes along the convex portion protruding toward the liquid crystal layer, so that unexpected alignment of liquid crystal molecules due to the influence of adjacent subpixels is suppressed. Thus, light leakage can be reduced.

In the liquid crystal display panel of the present invention, the height of the convex portion is 0.2 μm or more and 0.4 μm.
It is preferable that the width in the short direction at the top of the convex portion is 2 μm or more and less than 4 μm.

When the height of the convex portion is less than 0.2 μm or the width in the short direction at the top of the convex portion is less than 2 μm, the light leakage suppressing effect due to the formation of the convex portion is not clearly exhibited. The upper limit of the height of the convex portion is proportional to the cell gap, and if the height of the convex portion becomes too high, the effect starts to decrease, but the light leakage suppression effect is better than when the convex portion is not formed. Play. A preferable height of the convex portion is about 0.2 to 0.4 μm. Moreover, although the upper limit of the width | variety of the transversal direction in the top part of a convex part is decided by the width | variety between the pixel electrodes of an adjacent sub pixel, about 2-8 micrometers is preferable.

In the liquid crystal display panel of the present invention, the convex portion has a width in the short direction on the base side (bottom side) of the convex portion longer than a width in the short direction on the top side of the convex portion. In addition, it is preferable that a taper is formed on the side surface of the convex portion.

According to the liquid crystal display panel of the present invention, even if the convex portion has no taper, a better light leakage suppression effect can be obtained as compared with the case where the convex portion is not provided. A suppression effect can be produced.

Moreover, in the liquid crystal display panel of this invention, it is preferable that the said convex part is formed in the said 2nd board | substrate.

Rather than forming the protrusion on the first substrate side where the pixel electrode for driving the liquid crystal layer is formed, the second
The effect of suppressing light leakage from the formation of the convex portion is better when formed on the substrate side. for that reason,
According to the liquid crystal display panel of the present invention, an ECB mode liquid crystal display panel in which light leakage is further suppressed can be obtained.

In the liquid crystal display panel of the present invention, it is preferable that the second substrate has color filters of different colors in adjacent sub-pixels, and the convex portion is formed by overlapping of the adjacent color filters.

The color filter layer is formed in a stripe shape along the longitudinal direction of each sub-pixel.
Therefore, according to the liquid crystal display panel of the present invention, it is possible to easily form the convex portion on the second substrate without particularly increasing the number of steps.

In the liquid crystal display panel of the present invention, the second substrate has a color filter of a different color in adjacent sub-pixels and a resin layer formed so as to cover the color filter, and the convex portion is It is preferable that it consists of the convex part formed in the said resin layer.

In order to flatten the level difference caused by the color filter layers of different colors or to block impurities flowing out from the color filter from entering the liquid crystal layer, a resin layer may be formed so as to cover the color filter. According to the liquid crystal display panel of the present invention, since the convex portion is formed using this resin layer, the convex portion can be easily formed without increasing the number of steps.

In the liquid crystal display panel of the present invention, it is preferable that the convex portion is formed between all the sub-pixels.

In a liquid crystal display device for color display, the sub-pixels adjacent in the scanning line direction have different color filters, so the gradation between the sub-pixels adjacent in the scanning line direction is often different. For this reason, light leakage may occur in the longitudinal direction between all the sub-pixels. In the liquid crystal display panel of the present invention, since the convex portions are formed in the longitudinal direction between all the sub-pixels, an ECB mode liquid crystal display panel in which light leakage is further suppressed can be obtained.

In the liquid crystal display panel of the present invention, the normally white mode is preferable.

In the ECB mode liquid crystal display panel, light leakage is more noticeable in the normally white mode than in the normally black mode. Therefore, according to the liquid crystal display panel of the present invention, the light leakage suppressing effect is more remarkably exhibited.

FIG. 3 is a plan view illustrating an outline of subpixels of the liquid crystal display panel according to the first embodiment. It is sectional drawing of the II-II line of FIG. It is sectional drawing of the III-III line | wire of FIG. It is sectional drawing of the IV-IV line of FIG. It is sectional drawing corresponding to FIG. 3 of 2nd Embodiment. It is sectional drawing corresponding to FIG. 3 of 3rd Embodiment. 7A shows a case where a convex portion with a taper is formed on the second substrate side, FIG. 7B shows a case where there is no convex portion, and FIG. 7C shows a case where a convex portion without a taper is formed on the second substrate side. It is a figure which shows each light leakage level. 8A shows a case where the convex portion width of FIG. 7A is doubled, FIG. 8B shows a case where the height of the convex portion of FIG. 7A is doubled, and FIG. 8C shows a case where the convex portion is formed on the first substrate side. It is a figure which shows each light leakage level in the case of being. It is sectional drawing for demonstrating the motion of the liquid crystal molecule of the liquid crystal display panel of the ECB mode of a prior art example.

The best mode for carrying out the present invention will be described below with reference to the embodiments and drawings. However, the embodiments shown below are not intended to limit the present invention to those described herein. The present invention can be equally applied to various modifications without departing from the technical idea shown in the claims. In each drawing used for the description in this specification, each layer and each member are displayed in different scales so that each layer and each member can be recognized on the drawing. However, it is not necessarily displayed in proportion to the actual dimensions.

[First Embodiment]
The structure of the main part of the display area of the liquid crystal display panel 10A of the first embodiment will be described with reference to FIGS. FIG. 1 is a plan view showing an outline of sub-pixels of the liquid crystal display panel according to the first embodiment. 2 is a cross-sectional view taken along line II-II in FIG. 3 is a cross-sectional view taken along line III-III in FIG. 4 is a cross-sectional view taken along line IV-IV in FIG.

In the liquid crystal display panel 10A of the first embodiment, the liquid crystal layer LC has an array substrate AR (the first embodiment of the present invention).
And a color filter substrate CF (corresponding to the second substrate of the present invention). The array substrate AR is based on a first transparent substrate 11 made of transparent insulating glass, quartz, plastic, or the like. On the first transparent substrate 11, a scanning line 12 made of opaque metal such as aluminum or molybdenum is extended in the X-axis direction (row direction) in FIG. 1 on the side facing the liquid crystal layer LC. A gate electrode G extends from the scanning line 12 upward in FIG. Further, the auxiliary capacitance line 13 is formed in parallel with the scanning line 12, and the auxiliary capacitance line 13 at the position where each subpixel SP is to be formed has a portion facing a contact hole 20 described later as shown in FIG. The auxiliary capacitance electrode 14 is formed to be wide.

A transparent gate insulating film 15 made of silicon nitride, silicon oxide, or the like is laminated so as to cover the scanning line 12, the gate electrode G, the auxiliary capacitance line 13, and the auxiliary capacitance electrode. A semiconductor layer 16 made of amorphous silicon, polycrystalline silicon, or the like is formed on the gate insulating film 15 overlapping the gate electrode G in plan view. On the gate insulating film 15, a plurality of signal lines 17 made of a metal such as aluminum or molybdenum are extended in the Y-axis direction (column direction) in FIG. A source electrode S extends from the signal line 17, and the source electrode S is connected to the semiconductor layer 1.
6 in partial contact with the surface.

Further, a drain electrode D formed simultaneously with the same material as the signal line 17 and the source electrode S is provided on the gate insulating film 15, and the drain electrode D is disposed in proximity to the source electrode S and the semiconductor layer 16. It partially contacts and overlaps with the auxiliary capacitance electrode 14 in plan view. A region surrounded by the scanning lines 12 and the signal lines 17 corresponds to one sub-pixel region. For example, light 3
Three subpixels SP of primary colors R (red), G (green), and B (blue) constitute one pixel. Since one pixel is substantially square, the subpixel SP that divides this into three equal parts is scanned. Line 12 side is short side and signal line 1
The 7 side becomes a long rectangle. A thin film transistor TFT (Thin) serving as a switching element by the gate electrode G, the gate insulating film 15, the semiconductor layer 16, the source electrode S, and the drain electrode D
Film TFT) is formed, and this TFT is formed in each sub-pixel SP.

Further, a transparent passivation film 18 made of, for example, silicon nitride or silicon oxide is laminated so as to cover the exposed portions of the signal line 17, the TFT, and the gate insulating film 15. Then, in order to cover the passivation film 18, ITO (Indium Thin Oxide) or I
A pixel electrode 19 made of a transparent conductive material such as ZO (Indium Zinc Oxide) is formed. A contact hole 20 that penetrates the passivation film 18 and reaches the drain electrode D is formed, and the pixel electrode 19 and the drain electrode D are electrically connected through the contact hole 20. An alignment film 21 made of polyimide, for example, is stacked so as to cover the pixel electrode 19. The alignment film 21 is rubbed in a predetermined direction (right direction in FIG. 1).

The color filter substrate CF is based on a second transparent substrate 22 made of transparent insulating glass, quartz, plastic or the like. On the second transparent substrate 22, a light shielding layer 23 made of an opaque resin material and a color filter layer 24 that transmits light of different colors (for example, R, G, B) for each subpixel SP are formed. As shown in FIG. 2, the light shielding layer 23 is formed so as to overlap the TFT, the scanning line 12, and the signal line 17 in a plan view. The light shielding layer 23 of the sub-pixel SP
A color filter layer 24 is formed in a region where no is formed. A counter electrode 25 made of a transparent conductive material such as ITO or IZO so as to cover the color filter layer 24
Is formed across all sub-pixels SP. An alignment film 26 made of polyimide, for example, is formed so as to cover the counter electrode 25. The alignment film 26 is rubbed in the direction opposite to that of the alignment film 21.

The array substrate AR and the color filter substrate CF thus formed are opposed to each other, a sealing material (not shown) is provided around both substrates, and the substrates are bonded together, and a liquid crystal is filled between the substrates. Thus, the liquid crystal display panel 10A according to the first embodiment is obtained.
A spacer (not shown) for holding the liquid crystal layer LC at a predetermined thickness is formed on the color filter substrate CF.

With the above configuration, when the TFT is turned on and a voltage is applied between the pixel electrode 19 and the counter electrode 25, an electric field is generated between the electrodes 19 and 25, and the alignment of the liquid crystal molecules in the liquid crystal layer LC changes.
As a result, the light transmittance of the liquid crystal layer LC changes and an image is displayed. The liquid crystal display panel 10A operates in a normally white mode in which light is transmitted when no voltage is applied and white is displayed, and when voltage is applied, the light is blocked and black is displayed. The auxiliary capacitance portion is formed by the auxiliary capacitance electrode 14, the drain D, and the gate insulating film 15, and the electric field between the electrodes 19 and 25 is held for a predetermined time when the TFT is turned off.

Next, the operation of the convex portion protruding toward the liquid crystal layer LC in the first embodiment will be described.
As shown in FIG. 3, the color filter layer 24 of the sub-pixel SP on both sides at the boundary of the sub-pixel SP.
Are overlapped with each other, so that a convex portion B1 of the color filter layer 24 is formed. The convex portion B1 of the color filter layer 24 is formed between all the sub-pixels so as to overlap with the signal line in plan view in parallel with the signal line 17. A counter electrode 25 is formed so as to cover the color filter layer 24, and an alignment film 26 is formed so as to cover the counter electrode 25.
For this reason, the convex portion B2 of the alignment film 26 is formed using the convex portion B1 of the color filter layer 24 as a base. The height of the convex portion B1 is H, and the width of the top portion is L. Alignment film 2
The direction of the rubbing process No. 6 changes along the surface of the convex portion B2. Therefore, as shown in FIG. 3, the unexpected alignment of the liquid crystal molecules due to the influence of the adjacent subpixel is suppressed in the convex portion B <b> 2, and light leakage in the adjacent vicinity A portion of the subpixel can be reduced.

Further, by using an existing color filter layer, the convex portion B2 can be easily formed without increasing the number of steps. Also, in the liquid crystal display panel of the present invention, an example of a normally white mode ECB mode liquid crystal display panel has been shown, but light leakage of a normally white mode ECB mode liquid crystal display panel is E in a normally black mode.
Since it is more conspicuous than a CB mode liquid crystal display panel, the effect of the present invention can be confirmed more clearly.

Further, in the liquid crystal display panel 10A of the first embodiment, the convex portions are formed in the longitudinal direction between all the sub-pixels. As a result, since all the sub-pixels adjacent to each other in the scanning line direction have different color filters, the gradation between the sub-pixels adjacent to each other in the scanning line direction is often different. May leak light in the longitudinal direction. However, by applying the configuration of the present invention to all subpixels, light leakage can be efficiently reduced.

[Second Embodiment]
An ECB mode liquid crystal display panel 10B according to a third embodiment will be described with reference to FIG. In addition,
FIG. 5 is a cross-sectional view of the liquid crystal display panel 10B of the second embodiment corresponding to FIG. The liquid crystal display panel 10B of the second embodiment is the liquid crystal display panel 1 of the first embodiment in that the base of the convex portion is formed by halftone exposure after the overcoat layer 27 is solidly applied.
Although the configuration is different from 0A, the other configurations are substantially the same. Therefore, in the liquid crystal display panel 10B of the second embodiment, the same reference numerals are assigned to the same components as those of the liquid crystal display panel 10A of the first embodiment, and detailed description thereof is omitted.

In the ECB mode liquid crystal display panel 10B of the second embodiment, as shown in FIG. 5, the color filter layer 24 is formed substantially flat without forming a convex portion due to overlapping. An overcoat layer 27 having a convex portion B3 formed on the boundary of the sub-pixel SP is laminated so as to cover the color filter layer 24. Similar to the second embodiment, the counter electrode 25 and the alignment film 26 are formed so as to cover the overcoat layer 27 having the convex portion B3. Thereby, the convex part B4 of the alignment film 26 is formed with the convex part B3 of the overcoat layer 27 as a base.

Also in the ECB mode liquid crystal display panel 10B of the second embodiment, the EC of the first embodiment is used.
Similar to the B-mode liquid crystal display panel 10A, the direction of rubbing treatment of the alignment film 26 changes along the convex portion B4. Due to this change, unexpected alignment of liquid crystal molecules due to the influence of the adjacent sub-pixel is suppressed, and light leakage in the adjacent vicinity A portion of the sub-pixel can be reduced. As described above, the convex portion is formed by using the overcoat layer 27 for flattening a step due to the color filter layers of different colors or blocking impurities flowing out from the color filter layer from entering the liquid crystal layer LC. By forming, the convex portion B4 can be easily made without increasing the number of steps.
Will be able to form.

[Third Embodiment]
An ECB mode liquid crystal display panel 10C of the third embodiment will be described with reference to FIG. In addition,
FIG. 6 is a cross-sectional view of a liquid crystal display panel 10C of the third embodiment corresponding to FIG. In the liquid crystal display panel 10C of the third embodiment, the convex portion is not the color filter substrate CF but the array substrate A.
The liquid crystal display panel 10A according to the first embodiment is formed in the shape R and the other configurations are the same.
Is substantially the same. Therefore, in the liquid crystal display panel 10C of the third embodiment, the first
Parts having the same configuration as the liquid crystal display panel 10A of the embodiment are given the same reference numerals, and detailed description thereof is omitted.

In the ECB mode liquid crystal display panel 10C of the third embodiment, as shown in FIG. 6, a convex portion B5 made of a transparent resin material such as a photoresist is formed on the boundary of the subpixel SP on the upper layer of the pixel electrode 19. Yes. The convex portion B5 is formed so that the shape of the convex portion B5 remains by exposure and development after the transparent resin material is solidly applied. An alignment film 21 is formed so as to cover the overcoat layer 28 having the convex portions B5. Thereby, the convex part B6 of the alignment film 21 is formed with the convex part B5 as a base. Similar to the ECB mode liquid crystal display panel 10A of the first embodiment, the direction of the rubbing treatment of the alignment film 21 changes along the surface of the projection B6. Due to this change, in the ECB mode liquid crystal display panel 10C of the fourth embodiment as well, unexpected alignment of liquid crystal molecules due to the influence of adjacent subpixels is suppressed, and light leakage in the vicinity A portion of the subpixels is reduced. be able to.

[Light leakage measurement results]
Next, how the degree of light leakage varies depending on the shapes and dimensions of various convex portions will be described with reference to FIGS. Note that the left axis in FIGS. 7 and 8 represents the distance from the surface of the array substrate, and here the cell gap is constant at 4 μm. Also, the right axis of FIGS. 7 and 8 represents the transmittance, and a large transmittance indicates that light leakage is large. Further, the horizontal axis in FIGS. 7 and 8 indicates the position in the width direction of each sub pixel from the reference position (left end), and the portion where the curve is drawn is the position corresponding to each sub pixel, that is, the signal line. It corresponds to. In all of FIGS. 7 and 8, the rubbing direction is from the right to the left on the array substrate side, and the color filter substrate side is from the left to the right on the drawing.

FIG. 7A shows a case where the shape and dimensions of the convex portions formed on the color filter substrate are basic shapes.
That is, it is a diagram showing the transmittance when the height H of the convex portion is 0.2 μm and the width L in the short direction of the top portion of the convex portion is 4 μm. FIG. 7B shows a case where no protrusion is formed on the color filter substrate. As is clear from comparison between FIGS. 7A and 7B, it is understood that when the convex portion having the basic shape is formed on the color filter substrate, the region where light leakage occurs is narrowed and the light leakage amount is reduced. In FIG. 7B, light leakage occurs almost symmetrically, but in FIG. 7A, it is asymmetrical. The reason why such a phenomenon occurs is that the alignment direction of the liquid crystal molecules on the surface of the alignment film of the color filter substrate when no voltage is applied is uniform unless convex portions are formed on the color filter substrate. If convex portions are formed on the color filter substrate, it is presumed that the liquid crystal alignment directions are different at the tapered portions on both sides of the convex portions.

Further, the convex portions formed on the color filter substrate in FIG. 7C are not tapered, and the convex portion height H is 0.2 μm and the convex portion width L is 4 μm. In the case of FIG. 7C as well, it can be seen that the light leakage is greatly reduced as compared with the case of FIG. However, light leakage is larger than that in the case of FIG. Therefore, in the present invention, it can be seen that the formation of a taper on the convex portion provides a better light leakage suppression effect than the case where the taper is not formed.

FIG. 8A shows an example in which the width of the convex portion of the basic shape shown in FIG. 7A is doubled. That is, the height H of the convex portion is 0.2 μm, and the width L in the short direction of the top portion of the convex portion is 8 μm. In the case of FIG. 8A as well, it can be seen that the light leakage is greatly reduced as compared with the case of FIG. However, light leakage is larger than in the case of FIG. 7A.

Usually, the distance between the pixel electrodes of a small and medium-sized liquid crystal display panel to which the ECB mode liquid crystal display panel is applied is set to about 5 to 6 μm, and the top of the convex portion obtained as a result of FIG. The width is larger than the distance between the pixel electrodes. Therefore, it can be said that the preferable upper limit value of the width L in the short direction of the top of the convex portion is determined by the distance between the pixel electrodes, but generally L = 4 to 8 μm.
If it is about m, it can be said that a good light leakage suppression effect can be achieved.

FIG. 8B shows an example in which the height of the convex portion of the basic shape shown in FIG. 7A is doubled.
That is, the height H of the convex portion is 0.4 μm, and the width in the short direction of the top portion of the convex portion is L = 4 μm. In the case of FIG. 8B as well, it can be seen that the light leakage is greatly reduced as compared with the case of FIG. However, light leakage on the right side of the convex portion on the drawing is larger than in the case of FIG. 7A, but light leakage on the left side is smaller.

Such a phenomenon is caused by the fact that the alignment direction of the liquid crystal is greatly different from the case shown in FIG. 7A in the tapered portions on both sides of the convex portion due to the height of the convex portion. Presumed. Thus, if the difference in light leakage between the two sides of the convex portion becomes large, as a result, the larger light leakage becomes noticeable. Therefore, the height of the convex portion is about H = 0.2 μm to 0.4 μm. Seems to be preferred.

FIG. 8C is a diagram in which convex portions having the basic shape shown in FIG. 7A are formed on the array substrate side. In the case of FIG. 8C as well, it can be seen that the light leakage is greatly reduced as compared with the case of FIG. However, light leakage is larger than in the case of FIG. 7A. Therefore, it can be seen that the convex portions should be formed on the color filter substrate side.

Although not shown in the drawings, the taper portion of the convex portion formed on the color filter substrate side is formed only on the right side portion or only on the left side portion in the drawing, and the light leakage level is substantially reduced between the two. Although no difference was observed, the light leakage was slightly less than that without the taper shown in FIG. 7C, and the light leakage was slightly larger than that in the basic shape of FIG. 7A. for that reason,
In particular, there is no advantage of forming the taper only on one side of the convex portion.

DESCRIPTION OF SYMBOLS 10A-10D ... Liquid crystal display panel 11 ... Transparent substrate 12 ... Scanning line 13 ... Auxiliary capacity line 14 ... Auxiliary capacity electrode 15 ... Gate insulating film 16 ... Semiconductor layer 17 ... Signal line 18 ... Passivation film 19 ... Pixel electrode 20 ... Contact hole 21, 26 ... Alignment film 2
2 ... Transparent substrate 23 ... Light shielding layer 24 ... Color filter layer 25 ... Counter electrode 27, 28
... overcoat layer AR ... array substrate B1 to B6 ... convex CF ... color filter substrate LC ... liquid crystal layer SP ... subpixel

Claims (8)

An electric field control complex having a first substrate and a second substrate disposed opposite to each other with a liquid crystal layer interposed therebetween, and having a pixel electrode formed for each subpixel in the driving region of the first substrate and driving the liquid crystal layer. A refraction mode liquid crystal display panel,
The liquid crystal display panel according to claim 1, wherein a convex portion protruding toward the liquid crystal layer along the longitudinal direction of the sub pixel is formed between the sub pixels. 2. The liquid crystal according to claim 1, wherein a height of the convex portion is 0.2 μm or more and less than 0.4 μm, and a width in a short direction at a top portion of the convex portion is 2 μm or more and less than 4 μm. Display panel. The convex portion has a taper formed on a side surface of the convex portion so that a width in a short direction on a base side of the convex portion is longer than a width in a short direction on a top side of the convex portion. The liquid crystal display panel according to claim 1. The liquid crystal display panel according to claim 1, wherein the convex portion is formed on the second substrate. The said 2nd board | substrate has a color filter of a different color by an adjacent sub pixel, The said convex part is formed by the overlap of the said adjacent color filter.
A liquid crystal display panel as described in 1. The second substrate has a color filter of a different color in adjacent sub-pixels and a resin layer formed so as to cover the color filter, and the convex portion is a convex portion formed in the resin layer. The liquid crystal display panel according to claim 5. The liquid crystal display panel according to claim 1, wherein the convex portion is formed between all sub-pixels. The liquid crystal display panel according to claim 1, wherein the liquid crystal display panel is in a normally white mode.