JP2011028020A - Liquid crystal display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display panel that light-shields a region where rubbing processing by a columnar spacer cannot be normally performed and adjusts white balance, even if the region where the rubbing processing cannot be normally performed is formed in the liquid crystal display panel whose area is modulated. <P>SOLUTION: In the liquid crystal display panel 10A that includes the columnar spacer 25 and is rubbing-processed, the aperture ratio is made smaller than sub-pixels 12RA and 12BA of another color by addition of a light shielding layer 28aA in one or more sub-pixels 12GA in a pixel 11A, and the added light shielding layer 28aA is overlaid on a region 32 where the alignment of the rubbing processing is disturbed by the columnar spacer 25. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a liquid crystal display panel having sub-pixels whose transmittance is different from the transmittance of sub-pixels of other colors, and in which deterioration of optical characteristics in an alignment disorder region of a columnar spacer is reduced.

Liquid crystal display panels are characterized by their light weight, thinness, and low power consumption compared to CRTs (cathode ray tubes), and are therefore used in many electronic devices for display purposes. The liquid crystal display panel 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 a reflective type in which external light is incident on the liquid crystal layer, reflected by the reflector, then transmitted through the liquid crystal layer again, and a transmissive type in which incident light from the backlight device is transmitted through the liquid crystal layer. And a transflective type having both properties.

As a method for applying an electric field to a liquid crystal layer of a liquid crystal display panel, there are a vertical electric field method and a horizontal electric field method. A vertical electric field type liquid crystal display panel applies a substantially vertical electric field to liquid crystal molecules by a pair of electrodes arranged with a liquid crystal layer interposed therebetween. As this vertical electric field type liquid crystal display panel, TN (Twisted Nematic) mode, VA (Vertical Alignment)
Mode, MVA (Multi-domain Vertical Alignment) mode, ECB (Electrically Co
The ntrolled birefringence mode is known.

In addition, a horizontal electric field type liquid crystal display panel is provided with a pair of electrodes insulated from each other on one inner surface side of a pair of substrates arranged with a liquid crystal layer sandwiched therebetween, so that a substantially horizontal electric field It is applied to molecules. This horizontal electric field type liquid crystal display panel includes an IPS (In-Plane Switching) mode in which a pair of electrodes do not overlap in a plan view, and an overlapping FFS (Fr
inge Field Switching) mode is known. The liquid crystal display panel of the horizontal electric field type has an effect that a wide viewing angle can be obtained.

Also, there are monochrome display type and color display type liquid crystal display panels. The color of one pixel (one pixel) of a color display type liquid crystal display panel is, for example, R (red), G (
It is determined by the color mixture of the light transmitted through the sub-pixels individually provided with the color filters of the three primary colors of light (green) and blue (blue). For example, an 8-bit voltage corresponding to 0 to 255 gradations is R, G
When applied to each sub-pixel of B, the luminance of each sub-pixel becomes 256 types, and a number of colors can be displayed by one pixel depending on the combination of the luminance of each sub-pixel.
In such a liquid crystal display panel in which one pixel is formed by each of the R, G, and B sub-pixels, R,
White display is obtained by lighting all the G and B sub-pixels with the same gradation.

However, due to the formation error of each layer in the liquid crystal display panel and process variation, R, G
, B sub-pixels may lose their chromaticity and luminance balance, and even when the same gradation voltage is applied to the R, G, B sub-pixels, the white sub-pixels may not become white. In addition, a transparent material such as a resin layer is not completely colorless and may be yellowish, for example. In general, the human eye is the least sensitive to light of the blue color, second most sensitive to light of the red color, and most sensitive to light of the green color. There are features. As a method of solving such a problem with a simple structure, as shown in Patent Document 1 below, by adjusting the area of the light shielding layer, an aperture of at least one subpixel of R, G, B is formed. How to adjust the rate small (hereinafter,
This method is referred to as “area modulation”. ) Is considered.

On the other hand, spacers such as spherical spacers and columnar spacers are used in the liquid crystal display panel in order to keep the thickness of the liquid crystal layer constant. The spherical spacers are scattered in the liquid crystal layer in the display area. If the spherical spacers are dispersed in the liquid crystal layer in the display area, the alignment of liquid crystal molecules is disturbed, which causes light leakage. On the other hand, the columnar spacer is integrally formed on the array substrate or the color filter substrate, so that it can be disposed in the light-shielding area while avoiding the portion through which light passes, thereby obtaining a good display quality. Is possible. For this reason, columnar spacers are used in many liquid crystal display panels.

When the area density (density per unit area in the display area) of the columnar spacer increases, the deformation strength against external force perpendicular to the substrate surface increases, but the frictional force increases against external force parallel to the substrate surface. Even if released from external force, the displacement may not return. Also,
When the area density of the columnar spacers increases, the deformation is reduced when a large external force is applied, but the impact on the liquid crystal layer is increased, so that bubbles are easily generated when the impact is received at a low temperature. This bubble is said to be generated when the dissolved amount of the gas dissolved in the liquid crystal under normal temperature and normal pressure reaches a saturated state at a low temperature and an impact is applied to the display surface. Therefore, it is necessary to arrange the columnar spacers to have an appropriate area density.

Further, as shown in Patent Document 2 below, a liquid crystal display panel using a two-stage columnar spacer having an auxiliary columnar spacer slightly shorter than a main columnar spacer having a conventional length is also known. When this two-stage columnar spacer is used, the auxiliary columnar spacer is separated from one of the substrates. Therefore, when a large external force exceeding a predetermined level is applied, the auxiliary columnar spacer contacts the opposite substrate after the main columnar spacer is deformed. As a result, further deformation of the liquid crystal display panel can be prevented. Further, when an external force parallel to the substrate surface is applied and then released from the external force, the auxiliary columnar spacer is separated from one substrate, so that there is little friction and the deviation easily returns to the original state.

This columnar spacer is formed on at least one substrate, and then an alignment film is formed, and this alignment film is rubbed. In the rubbing process, a large number of fine grooves along one direction are formed in the alignment film by rubbing the alignment film with a rotating rubbing cloth. In a state where no electric field is applied to the liquid crystal layer, the liquid crystal molecules are aligned according to the rubbing direction. However, since the columnar spacer becomes a convex part, the bristles of the rubbing cloth will be depressed by hitting the columnar spacer during the rubbing process, so that the normal rubbing process is not performed in the area where the columnar spacer has a tail, The alignment of the liquid crystal molecules will be disturbed. In such a region where the alignment of the liquid crystal molecules is disturbed, the optical characteristics are deteriorated, for example, the transmittance is decreased. As a countermeasure against this, Patent Document 3 below discloses a liquid crystal display panel in which the rubbing treatment direction is set so that a region in which the alignment of liquid crystal molecules is disturbed does not overlap the pixel electrode.

JP-A-2005-99455 JP 2007-334003 A Japanese Patent Laid-Open No. 11-174467

However, in a liquid crystal display panel, it is difficult to change the direction of rubbing treatment in order to prevent disorder of the alignment of liquid crystal molecules. For example, in a horizontal electric field type liquid crystal display panel in which a slit is formed in a pixel electrode or the like, the rubbing process direction is set to an optimum angle (for example, 5 degrees) with respect to the slit extending direction, and the ECB mode In the liquid crystal display panel, the rubbing direction is set to an optimum angle (for example, 45 degrees) with respect to the polarization direction of the polarizing plate. Such a problem of disorder of alignment of liquid crystal molecules due to columnar spacers also occurs in a liquid crystal display panel in which area modulation is performed as described in Patent Document 1.

The inventors have made various studies in order to solve the problem of the disorder of the alignment of liquid crystal molecules due to the columnar spacers in the liquid crystal display panel in which the above-described area modulation is performed. As a result, in the liquid crystal display panel in which area modulation is performed, there are subpixels in which the area of the light-shielding region is wider than subpixels of other colors. The inventors have found that by optimizing the arrangement of the light-shielding regions, it is possible to suppress the deterioration in display image quality caused by the disorder of the alignment of the liquid crystal molecules due to the columnar spacers, and the present invention has been completed.

That is, an object of the present invention is to provide a liquid crystal display panel in which display quality is prevented from being deteriorated due to poor alignment of liquid crystal molecules due to the presence of columnar spacers in a liquid crystal display panel subjected to area modulation. .

In order to achieve the above object, the liquid crystal display panel of the present invention comprises:
A first substrate and a second substrate disposed opposite to each other with a liquid crystal layer interposed therebetween;
The first substrate includes a plurality of scanning lines and signal lines formed so as to intersect with each other while being insulated from each other, and a pixel electrode formed for each sub-pixel partitioned by the scanning lines and signal lines. ,
In the second substrate,
A light shielding layer formed so as to overlap with the scanning line and the signal line in plan view, and a color filter layer formed for each sub-pixel partitioned by the scanning line and the signal line,
A rubbing alignment film is formed on the surface of the first substrate and the second substrate on the liquid crystal layer side, and a columnar spacer is formed on at least one of the first substrate and the second substrate. A liquid crystal display panel in which one pixel is composed of a plurality of sub-pixels having the color filter layer,
The aperture ratio of one or more subpixels in the one pixel is reduced by making the area of the light shielding layer wider than the subpixels of other colors,
The area where the area of the light shielding layer is widened overlaps with an area where the rubbing process is not performed normally, which is located downstream in the rubbing process direction starting from the columnar spacer in plan view. .

In the liquid crystal display panel of the present invention, one pixel is composed of a plurality of subpixels each having a color filter layer of a different color, and one or more subpixels in one pixel are more than subpixels of other colors. The aperture ratio is reduced by increasing the area of the light shielding layer. With such a configuration, area modulation for adjusting the transmittance of each color sub-pixel forming one pixel of the liquid crystal display panel is performed, and white balance can be appropriately maintained.

In addition, the rubbing process performed on the liquid crystal display panel forms a large number of fine grooves along one direction in the alignment film by rubbing the alignment film while rotating a rubbing cloth having fine hairs. Is. However, since the columnar spacer is a projection, the portion of the rubbing cloth that comes into contact with the columnar spacer during the rubbing process is once depressed. A certain amount of time is required until the recessed portion of the rubbing cloth returns to the original state, and the rubbing process is not normally performed on the recessed portion of the rubbing cloth. For this reason, an area in which the rubbing process is not normally performed is generated on the downstream side in the rubbing process direction from the columnar spacer until the recessed rubbing cloth returns to the original shape. In the region where the rubbing treatment is not normally performed, the alignment of the liquid crystal molecules in the liquid crystal layer is not normally performed, so that optical characteristics such as transmittance and contrast are deteriorated.

In the liquid crystal display panel of the present invention, the area where the area of the light shielding layer in the area modulation sub-pixel is widened overlaps with the area where the rubbing process is not normally performed in a plan view. Therefore, according to the liquid crystal display panel of the present invention, it is not necessary to form an additional light shielding layer corresponding to a region where the rubbing process using the columnar spacer is not normally performed separately from the light shielding layer of the sub-pixel where the area modulation is performed. As a result, it is possible to accurately display a white color while maintaining an appropriate white balance while suppressing an excessive decrease in transmittance of the sub-pixels subjected to area modulation.

In the liquid crystal display panel of the present invention, the columnar spacer may be formed on either the first substrate or the second substrate, and the cross section in the direction perpendicular to the axial direction (length direction) is circular or elliptical. The shape may be any shape such as a square shape, a triangular shape, and the axial cross section may be a square shape or a trapezoidal shape.

In the liquid crystal display panel of the present invention, it is preferable that the color filter layer includes red, green, and blue color filter layers, and the sub-pixel having a small aperture ratio includes a green sub-pixel.

Since green has high human visibility, a sub-pixel whose aperture ratio is smaller than that of other color sub-pixels for white balance adjustment is often a green sub-pixel. When the columnar spacer is disposed in the green sub-pixel, an area where the rubbing process is not normally performed is formed in the green sub-pixel area. However, a reduction in transmittance based on the area where the rubbing process is not normally performed is reduced. Especially noticeable. In the liquid crystal display panel of the present invention, the area where the area of the light shielding layer necessary for area modulation is increased is also used for light shielding in areas where the rubbing treatment is not normally performed. Therefore, according to the liquid crystal display panel of the present invention, the light shielding layer for shielding the region where the rubbing treatment using the columnar spacers is not normally performed separately from the light shielding layer for reducing the aperture ratio for area modulation is formed. This eliminates the need for the white sub-pixel, while maintaining an appropriate white balance and accurately displaying white while suppressing a decrease in the extra transmittance of the green sub-pixel. In addition, in order to precisely control the white balance, it is possible to adopt the above-described configuration not only for the green sub-pixel but also for other color sub-pixels, for example, the red sub-pixel or the blue sub-pixel. It is.

Further, in the liquid crystal display panel of the present invention, the shape of the light shielding region covering the region where the rubbing process is not normally performed is that when the columnar spacer is projected at a predetermined elevation angle in the rubbing process direction. It is preferable that the projection shape is substantially the same.

The shape of the region where the rubbing process is not normally performed in the liquid crystal display panel is similar to the projected shape when the columnar spacer is projected at a predetermined elevation angle in the rubbing process direction,
The width is substantially equal to the width when the columnar spacer is projected. Therefore, according to the liquid crystal display panel of the present invention, the shape of the light-shielding region covering the region where the rubbing process is not normally performed,
Since the columnar spacer is substantially the same as the projection shape when projected at a predetermined elevation angle in the rubbing direction, while suppressing the decrease in the excess transmittance of the sub-pixel where the area modulation is performed, Accurate white display can be achieved with appropriate white balance. Note that the predetermined elevation angle changes depending on the rotational diameter, rotational speed, moving speed, etc. of the rubbing cloth.
It may be determined experimentally.

Further, in the liquid crystal display panel of the present invention, the shape of the light shielding region covering the region where the rubbing treatment is not normally performed is a square shape, and the width and length of the columnar spacer is the direction of the rubbing treatment. It is preferable that it is larger than the width and length when projected with a predetermined elevation angle.

In the liquid crystal display panel of the present invention, since the shape of the light-shielding region covering the region where the rubbing process is not normally performed is a square shape (rectangular shape or square shape), the region where the rubbing process is not normally performed easily It is possible to form a light shielding region that covers the film. Further, in the liquid crystal display panel of the present invention, the width and length of the light shielding area covering the area where the rubbing process is not normally performed are the width when the columnar spacer is projected at a predetermined elevation angle in the rubbing process direction. And larger than the length. Therefore, according to the liquid crystal display panel of the present invention,
Even if a positional shift or the like occurs when the first substrate and the second substrate are arranged to face each other, an area where the rubbing process is not normally performed can be reliably shielded from light, and the white balance is not easily lost.

In the liquid crystal display panel of the present invention, it is preferable that the columnar spacer is a mixture of high and low height spacers.

If the high and low columnar spacers are mixed, the low columnar spacers are not in contact with at least one of the first substrate and the second substrate. Therefore, according to the liquid crystal display panel of the present invention, when a large external force greater than a predetermined value is applied, one of the first substrate and the second substrate is deformed and comes into contact with the columnar spacer having a low height. Further deformation of one of the second substrates can be suppressed. In addition, when the external force is removed, the columnar spacer having a low height is separated from one of the first substrate and the second substrate, and against an external force parallel to one of the first substrate and the second substrate. Because there is little friction of
The deviation when released from external force is easy to return.

FIG. 2 is a plan view illustrating an outline of an array substrate for one pixel according to the first embodiment. It is sectional drawing of the II-II line | wire of FIG. 1 of 1st Embodiment. It is sectional drawing of the III-III line of FIG. 1 of 1st Embodiment. It is a top view which shows the outline | summary of the array substrate for 1 pixel of 2nd Embodiment. It is a top view which shows the outline | summary of the array substrate for 1 pixel of 3rd Embodiment. 6A is a diagram illustrating an example of an elliptical columnar spacer, FIG. 6B is a diagram illustrating an example of a square columnar spacer, and FIG. 6C illustrates an outline of an array substrate for one pixel according to the fourth embodiment. It is a partial top view. It is a partial top view which shows the outline | summary of the array substrate for 1 pixel of 5th Embodiment. FIG. 8A is a plan view showing an outline of an array substrate for two pixels according to the sixth embodiment, and FIG. 8B is a sectional view taken along line VIIIB-VIIIB in FIG. 8A.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described 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 changes made without departing from the technical idea shown in the claims.

Note that the “surface” of the array substrate and the color filter substrate described here indicates a surface on which various wirings are formed or a surface facing the liquid crystal. In addition, in each drawing used for the description in this specification, each layer and each member are displayed at 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]
A configuration of a main part of one pixel 11A of the liquid crystal display panel 10A of the first embodiment will be described with reference to FIGS. As shown in FIGS. 2 and 3, the liquid crystal display panel 10 </ b> A has a configuration in which the liquid crystal layer LC is sandwiched between the array substrate AR and the color filter substrate CF. Although not shown,
The liquid crystal display panel 10A has a plurality of sub-pixels aligned in the row direction and the column direction. One sub-pixel is composed of a region partitioned by the scanning line 13 and the signal line 14 formed on the array substrate AR. As shown in FIG. 1, one pixel 11A is composed of, for example, sub-pixels 12RA, 12GA, and 12BA that display three colors of R (red), G (green), and B (blue), and transmit each of these sub-pixels. The color of each pixel is determined by the color mixture of the light of the colors.

The array substrate AR is based on a first transparent substrate 15 made of transparent insulating glass, quartz, plastic or the like. On the first transparent substrate 15, as shown in FIG.
A scanning line 13 made of a metal such as aluminum or molybdenum is formed on the side facing the surface so as to extend in the X-axis direction (row direction) in FIG. From the scanning line 13, the gate electrode G is formed so as to extend to the lower left of each of the sub-pixels 12RA, 12GA, 12BA.

A transparent gate insulating film 16 made of silicon nitride, silicon oxide or the like is laminated so as to cover the scanning line 13 and the gate electrode G. A semiconductor layer 17 made of amorphous silicon, polycrystalline silicon, or the like is formed on the gate insulating film 16 that overlaps the gate electrode G in plan view. A plurality of signal lines 14 made of a metal such as aluminum or molybdenum are formed on the gate insulating film 16 so as to extend to the left side of each of the sub-pixels 12RA, 12GA, and 12BA in the Y-axis direction (column direction) in FIG. Has been. A source electrode S extends from the signal line 14, and the source electrode S is in partial contact with the surface of the semiconductor layer 17.

Further, a drain electrode D formed simultaneously with the same material as the signal line 14 and the source electrode S is provided on the gate insulating film 16, and the drain electrode D is disposed in the vicinity of the source electrode S and the semiconductor layer 17. Partially touching. Since one pixel is substantially square, the sub-pixels 12RA, 12GA, and 12BA that divide the pixel into three are rectangles having a short side on the scanning line 13 side and a long side on the signal line 14 side. The gate electrode G, the gate insulating film 16, the semiconductor layer 17, the source electrode S, and the drain electrode D constitute a TFT serving as a switching element.
This TFT is formed in RA, 12GA, and 12BA.

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 14, the thin film transistor TFT, and the gate insulating film 16. An interlayer resin film 19 made of a transparent resin material such as a photoresist is laminated so as to cover the passivation film 18. And interlayer resin film 1
A lower electrode 20 made of a transparent conductive material such as ITO (Indium Thin Oxide) or IZO (Indium Zinc Oxide) is formed so as to cover 9. A contact hole 21 reaching the drain electrode D through the interlayer resin film 19 and the passivation film 18 is formed,
The lower electrode 20 and the drain electrode D are electrically connected through the contact hole 21. Therefore, the lower electrode 20 operates as a pixel electrode.

A transparent interelectrode insulating film 22 made of, for example, silicon nitride or silicon oxide is laminated so as to cover the lower electrode 20. An upper electrode 23 made of a transparent conductive material such as ITO or IZO is formed so as to cover the interelectrode insulating film 22. In the liquid crystal display panel 10A of the present embodiment, the upper electrode 23 is connected to the common wiring at the periphery of the display area (not shown) and operates as a common electrode.

As shown in FIG. 1, the upper electrode 23 has a plurality of slit-like openings 24 formed in parallel at equal intervals. The slit-shaped openings 24 are formed by exposing and developing a photoresist material applied to the surface of the upper electrode 23 by photolithography and then etching. A columnar spacer 25 made of a resin having photosensitivity and insulation, for example, an acrylic resin, is formed on the upper electrode 23 overlapping the TFT in plan view by a photolithography method. The columnar spacer has a width of about 8 to 10 μm.
A first alignment film 26 made of, for example, polyimide is laminated so as to cover the upper electrode 23 and the columnar spacer 25. The first alignment film 26 is rubbed in a direction parallel to the X axis in FIG. 1 (parallel to the scanning line 13).

In the rubbing treatment, a large number of fine grooves along one direction are formed in the first alignment film 26 by rubbing the alignment film while rotating a rubbing cloth having fine hairs. Here, the rubbing treatment direction is inclined by a predetermined angle α with respect to the extending direction of the slit-like opening 24. By this rubbing treatment, the liquid crystal layer L in contact with the surface of the first alignment film 26
The liquid crystal molecules of C can be aligned in one direction. The optimal value of α is
Although it varies depending on various conditions, it is preferably 3 to 15 degrees, and is 5 degrees here.

The color filter substrate CF is based on a second transparent substrate 27 made of transparent insulating glass, quartz, plastic, or the like. On the surface of the second transparent substrate 27, a light-shielding layer 28 made of a resin or metal material having a light-shielding property is formed at a position overlapping the scanning line 13, the signal line 14, and the TFT in a plan view. A color filter layer 29 that transmits light of different colors (for example, R, G, B, or colorless) for each of 12GA and 12BA is formed in a region that is not covered by the light shielding layer.

An overcoat layer 30 made of a transparent resin material such as a photoresist is laminated so as to cover the light shielding layer 28 and the color filter layer 29. The overcoat layer 30 is formed to flatten the steps due to the color filter layers 29 of different colors, and to block impurities flowing out from the light shielding layer 28 and the color filter layer 29 from entering the liquid crystal layer LC. It is. A second alignment film 31 made of, for example, polyimide is formed so as to cover the overcoat layer 30. The second alignment film 31 includes the first alignment film 26.
A rubbing process in the opposite direction to that is performed. The array substrate AR and the color filter substrate CF thus formed are opposed to each other, and a sealant (not shown) is provided around both substrates so that both substrates are bonded together, and homogeneously oriented liquid crystal is placed between both substrates. By filling, the liquid crystal display panel 10A according to the present embodiment is obtained.

With the above-described configuration, in the subpixels 12RA, 12GA, and 12BA, when the TFT is turned on, an electric field is generated between the lower electrode 20 and the upper electrode 23, and the alignment of 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 in the FFS mode. The region where the lower electrode 20 and the upper electrode 23 face each other with the interelectrode insulating film 22 interposed therebetween forms an auxiliary capacitance, and the electric field between the lower electrode 20 and the upper electrode 23 when the TFT is turned off. Is held for a predetermined time.

Next, the relationship between the area modulation mode and the columnar spacer 25 in the liquid crystal display panel 10A of the first embodiment will be described. Between the lower electrode 20 and the upper electrode 23 of the red subpixel 12RA, the green subpixel 12GA, and the blue subpixel 12BA, for example, an 8-bit gradation (
A voltage corresponding to 0 gradation to 255 gradation) is applied, and each can be displayed with a density of 256 gradations. In terms of design, if all the sub-pixels 12RA, 12GA, and 12BA have the same gradation at the same time, white display is performed.

However, in the conventional liquid crystal display panel, the chromaticity and luminance balance of R, G, and B are destroyed due to the difference in the behavior of liquid crystal molecules in the liquid crystal display panel and the process variation, so that all sub-pixels have the same gradation. Even when a voltage is applied, it may not be completely white. In addition, a transparent material such as a resin layer is not completely colorless and may be yellowish, for example. In general, the human eye has the lowest visual sensitivity for the blue system, followed by the visual sensitivity for the red system, and is highly sensitive to light of the green color. Therefore, in the liquid crystal display panel 10A of the first embodiment, an additional light shielding layer 28aA (see FIG. 1) is added to the green sub-pixel 12GA.
By forming the portion, the aperture ratio of the green sub-pixel 12GA is red.
Area modulation is performed so as to be smaller than the aperture ratio of the A and blue sub-pixels 12BA so that white display can be performed accurately. In FIG. 1, in order to make the drawing easy to see, only the additional light shielding layer 28aA of the light shielding layer 28 is hatched, and the other portions of the light shielding layer are not hatched (the same applies hereinafter). .)

The columnar spacer 25 is, for example, an upper electrode 23 that overlaps with the TFT of the array substrate AR in plan view.
Formed on top. One columnar spacer 25 may be provided for each pixel (3 sub-pixels) or one for each of a plurality of pixels. After the columnar spacer 25 is formed, the first alignment film 2
6 is formed, and the first alignment film 26 is rubbed in the right direction of FIG. Since the columnar spacers 25 are protrusions, the portion of the rubbing cloth that comes into contact with the columnar spacers 25 during the rubbing process is temporarily depressed. However, a certain amount of time is required until the recessed portion of the rubbing cloth returns to the original state, and the rubbing process is not normally performed on the recessed portion of the rubbing cloth.

Therefore, an area 32 where the rubbing process is not normally performed is generated on the downstream side in the rubbing process direction from the columnar spacer until the recessed rubbing cloth returns to the original shape. In the region 32 where the rubbing treatment is not normally performed, the alignment of the liquid crystal molecules of the liquid crystal layer LC is not normally performed, so that optical characteristics such as transmittance and contrast are deteriorated. The shape of the region 32 where the rubbing process is not normally performed is similar to the projected shape when the columnar spacer 25 is projected at a predetermined elevation angle β in the rubbing process direction as shown in FIG. The width is substantially equal to the width W1 when the columnar spacer 25 is projected, and the length L1 (see FIG. 1 respectively).
Is about 8 μm of the width of the columnar spacer 25 when it is short, and 100 μm when it is long
It may be about. Since 100 μm is a width of about one pixel, it may occur over the entire display area of the liquid crystal display panel 10A of the first embodiment. The predetermined elevation angle β varies depending on the rotational diameter, rotational speed, moving speed, etc. of the rubbing cloth, and may be determined experimentally.

However, the portion of the rubbing cloth that comes into contact with the columnar spacer 25 during the rubbing process is once depressed, but due to the elastic force of the rubbing cloth, the depth of the depression is most at the portion in contact with the center side of the columnar spacer 25. It is deep and shallow at the part in contact with the peripheral side of the columnar spacer 25. Therefore, after the rubbing cloth comes into contact with the column spacer 25, the column spacer 25
The portion that has come into contact with the peripheral side quickly returns to the original state, but the portion in contact with the center side of the columnar spacer 25 takes more time to return to the original state. For this reason, the shape of the region 32 where the rubbing process is not normally performed is not necessarily a rectangular shape, but can be regarded as a substantially rectangular shape because the width is small.

Further, since green has high human visibility, a sub-pixel whose aperture ratio is smaller than that of other color sub-pixels for white balance adjustment is often a green sub-pixel. However, when the region 32 where the rubbing process is not normally performed is formed in the green sub-pixel region by disposing the columnar spacer 25 in the green sub-pixel, the region 32 where the rubbing process is not normally performed is formed. The drop in transmittance is particularly noticeable.

Therefore, in the liquid crystal display panel 10A of the first embodiment, the region 32 where the rubbing process is not normally performed is not visible on the display region (opening) side of the green sub-pixel 12GA. The additional light shielding layer 28aA is formed by increasing the width of a part of the light shielding layer 28 so as to overlap the region 32 where the processing is not normally performed. By adopting such a configuration, the additional area of the light shielding layer 28aA can be used as an area where the area of the light shielding layer 28 required for area modulation is increased. Therefore, according to the liquid crystal display panel 10A of the first embodiment, an additional region corresponding to the region 32 where the rubbing process using the columnar spacer 25 is not normally performed separately from the light shielding layer for decreasing the aperture ratio for area modulation. Since it is not necessary to form a light shielding layer, white display can be performed accurately while maintaining an appropriate white balance while suppressing an excessive decrease in the transmittance of the green sub-pixel 12GA.

[Second Embodiment]
Next, the liquid crystal display panel 10B of 2nd Embodiment is demonstrated using FIG. FIG. 4 is a plan view of three sub-pixels corresponding to FIG. 1 in the liquid crystal display panel 10A of the first embodiment. Therefore, in the liquid crystal display panel 10B of the second embodiment, the same reference numerals are given to portions having the same configuration as the liquid crystal display panel 10A of the first embodiment, and the reference numerals having the subscript “A” are given. The subscript is changed to “B”, and the detailed description thereof is omitted.

The main differences between the liquid crystal display panel 10B of the second embodiment and the liquid crystal display panel 10A of the first embodiment are the extension direction and shape of the slit-like opening 24 formed in the upper electrode, and This is a difference in the rubbing direction. That is, the liquid crystal display panel 10 of the first embodiment.
In A, the extending direction of the slit-like opening 24 extends all along the scanning line 13 with a predetermined angle α in the lateral direction. On the other hand, in the liquid crystal display panel 10B of the second embodiment, the upper electrode 23 of each of the sub-pixels 12RB, 12GB, and 12BB constituting one pixel 11B.
The extending direction of the slit-shaped opening 24 formed in is a vertically long shape along the signal line 14 and is bent in a “<” shape. Therefore, the rubbing processing direction is parallel to the scanning lines 13 in the liquid crystal display panel 10A of the first embodiment, whereas it is parallel to the signal lines 14 in the liquid crystal display panel 10B of the second embodiment. ing.

Here, the slit-shaped opening 24 of the liquid crystal display panel 10B of the second embodiment will be described in detail. Since the sub-pixels 12RB, 12GB, and 12BB are vertically long, when the slit-shaped openings 24 are extended in the horizontal direction as in the liquid crystal display panel 10A of the first embodiment, the number of both ends of the slit-shaped openings 24 increases. The end of the slit-shaped opening 24 becomes an abnormal alignment region of liquid crystal molecules, leading to a decrease in the aperture ratio. Therefore, in the liquid crystal display panel 10B of the second embodiment, the extension direction of the slit-like opening 24 is set to the vertical direction, thereby reducing the number of ends of the slit-like opening 24 and reducing the decrease in the aperture ratio. Yes.

Further, in the liquid crystal display panel 10B of the second embodiment, since the slit-shaped opening 24 is formed in a “<” shape, the extending direction of the slit-shaped opening 24 is +5 degrees and −5 degrees with respect to the rubbing process direction. There is an inclined part. When all the slit-like openings 24 are tilted clockwise or counterclockwise with respect to the rubbing direction, the liquid crystal molecules are twisted in one direction, so that a phenomenon in which the color changes depending on the viewing angle direction appears. This is because the apparent retardation changes depending on the direction of viewing the liquid crystal molecules. Liquid crystal display panel 10 according to the second embodiment
In B, since the extending direction of the slit-like opening 24 is provided with a domain inclined by +5 degrees and a domain inclined by -5 degrees with respect to the clockwise direction, the phenomenon that the color changes depending on the viewing angle direction is canceled and suppressed. become.

The columnar spacer 25 of the liquid crystal display panel 10B of the second embodiment is the TF of the array substrate AR of the green sub-pixel 12GB, as in the case of the liquid crystal display panel 10A of the first embodiment.
It is formed on the upper electrode 23 that overlaps T in plan view. The first alignment film (not shown)
Are rubbed in a direction parallel to the Y-axis (the extending direction of the signal line 14) in FIG. Therefore, in the liquid crystal display panel 10B of the second embodiment, the region 32 where the rubbing process is not normally performed is generated upward along the signal line 14 of the green sub-pixel 12GB.

Therefore, in the liquid crystal display panel 10B of the second embodiment, an additional light shielding layer 28aB portion is formed so that the region 32 where the rubbing process is not normally performed cannot be seen on the display region (opening) side of the sub-pixel 12GB. The light shielding layer 28 is formed by increasing the width of a part thereof. With such a configuration, the additional area of the light shielding layer 28aB can be used as an area where the area of the light shielding layer 28 required for area modulation is increased.

[Third Embodiment]
Next, a liquid crystal display panel 10C of the third embodiment will be described with reference to FIG. FIG. 5 is a plan view of three sub-pixels corresponding to FIG. 1 in the liquid crystal display panel 10A of the first embodiment. Therefore, in the liquid crystal display panel 10C of the third embodiment, the same reference numerals are given to the parts having the same configuration as the liquid crystal display panel 10A of the first embodiment, and the reference numerals having the subscript “A” are given. The subscript is changed to “C”, and the detailed description thereof is omitted.

Differences in the main configuration between the liquid crystal display panel 10C of the third embodiment and the liquid crystal display panel 10A of the first embodiment are the extension direction and shape of the slit-like opening 24 formed in the upper electrode 23, and This is the difference in the rubbing direction. That is, in the liquid crystal display panel 10 </ b> A of the first embodiment, the extending directions of the slit-like openings 24 all extend at a predetermined angle α in the lateral direction along the scanning lines 13. On the other hand, in the liquid crystal display panel 10C of the third embodiment, the extending direction of the slit-like opening 24 formed in each upper electrode 23 of each of the sub-pixels 12RC, 12GC, and 12BC constituting one pixel 11C is a signal. It extends in a vertical direction along the line 14, and a part thereof is bent in a “<” shape. Therefore, the direction of the rubbing process is approximately 70 degrees with respect to the scanning line 13 in the liquid crystal display panel 10C of the third embodiment, while the direction of the rubbing process is parallel to the scanning line 13 in the liquid crystal display panel 10A of the first embodiment. Inclined.

Furthermore, in the liquid crystal display panel 10C of the third embodiment, the slit-shaped opening 24 is provided with a domain whose extending direction is inclined +5 degrees and a domain inclined -5 degrees with respect to the rubbing process direction. By tilting the rubbing direction in this way, it is possible to reduce the decrease in luminance when viewed with polarized sunglasses, or to correctly view even when the orientation of the display unit is changed on a mobile phone or the like. To be able to.

The columnar spacer 25 of the liquid crystal display panel 10C of the third embodiment is the TF of the array substrate AR in the green sub-pixel 12GC, as in the case of the liquid crystal display panel 10A of the first embodiment.
It is formed on the upper electrode 23 that overlaps T in plan view. The first alignment film 26 has the structure shown in FIG.
Since the rubbing process is performed in a direction inclined 70 degrees with respect to the scanning line 13 toward the upper right side, the region 32 where the rubbing process is not normally performed occurs toward the upper right side of the green sub-pixel 12GC. . Therefore, in the liquid crystal display panel 10C of the third embodiment, the additional light shielding layer 28a.
C is formed so as to extend in the upper right direction in FIG. 5 from the formation position of the columnar spacer 25 in a plan view so as to overlap with the entire region 32 where the rubbing process is not normally performed. This third
Also in the liquid crystal display panel 10 </ b> C of the embodiment, the light shielding layer 2 required for performing area modulation.
The increased area of 8 can be used also as the additional light shielding layer 28aC.

[Fourth Embodiment]
Although the columnar spacers 25 of the liquid crystal display panels 10A to 10C of the first to third embodiments are columnar, the present invention can also be applied to columnar spacers having shapes other than the columnar shape. An example of such a columnar spacer other than the columnar shape and the configuration of the liquid crystal display panel 10D of the fourth embodiment using the columnar spacer will be described with reference to FIGS. 6A to 6C. Note that FIG. 6C
As shown in FIG. 4, in the liquid crystal display panel 10D of the fourth embodiment, the extending direction of the slit-like openings 24 formed in the upper electrodes 23 of the sub-pixels 12RD, 12GD, and 12BD constituting the one pixel 11D. The shape is the same as that of the liquid crystal display panel 10C of the third embodiment. Therefore, in the liquid crystal display panel 10D of the fourth embodiment, parts having the same configuration as the liquid crystal display panel 10C of the third embodiment are given the same reference numerals or some reference numerals are deleted, and the subscript “ For reference signs with “C”, the subscript is changed to “D”, and the detailed description thereof is omitted.

In the liquid crystal display panel of the present invention, the columnar spacer 25 may have an elliptical columnar shape as shown in FIG. 6A or a rectangular columnar shape as shown in FIG. 6B. Thus, when the columnar spacer 25 is not a cylinder, as shown in FIGS. 6A and 6B, the width and area of the region 32 where the rubbing process is not normally performed vary depending on the rubbing process directions A1 to A3. Therefore, it is preferable to set the direction of the columnar spacer 25 so that the width and area of the region 32 where the rubbing process is not normally performed are reduced.

For example, as shown in FIG. 6C, when the cross section of the columnar spacer 25 is a rectangular prism shape, the rubbing process is not performed normally if the rubbing process is performed in the long side direction. Since the width W2 is reduced and the resistance of the rubbing process by the columnar spacer 25 is also reduced, the area of the region 32 where the rubbing process is not normally performed is also reduced. With such a configuration, the additional area of the light shielding layer 28aD can be used as an area where the area of the light shielding layer 28 required for area modulation is performed, and the rubbing process is not performed normally. The region 32 can be completely shielded from light.

6A to 6C show an elliptical and rectangular cross section in a direction perpendicular to the axial direction (length direction), other triangular shapes can be used. The cross section in the axial direction shows a rectangular shape, that is, a uniform thickness, but a trapezoidal shape, that is, a conical shape having a varying thickness can also be used.

[Fifth Embodiment]
Next, a liquid crystal display panel 10E according to a fifth embodiment will be described with reference to FIG. As shown in FIG. 7, in the liquid crystal display panel 10E of the fifth embodiment, the slit-shaped openings 24 formed in the upper electrodes 23 of the sub-pixels 12RE, 12GE, and 12BE constituting the one pixel 11E. As in the case of the liquid crystal display panel 10B of the second embodiment, the extending direction is a vertically long shape along the signal line 14 and is bent in a “<” shape. Therefore, in the liquid crystal display panel 10E of the fifth embodiment, parts having the same configuration as the liquid crystal display panel 10B of the second embodiment are given the same reference numerals or part of the reference numerals are deleted, and the subscript “ B
For reference numerals with "", the subscript is changed to "E", and the detailed description thereof is omitted.

The columnar spacers 25 of the liquid crystal display panels 10A to 10D of the first to fourth embodiments are all formed on the upper electrode 23 that overlaps with the TFT of the array substrate AR in a plan view. The present invention can also be applied to the formed columnar spacer. For example, in the liquid crystal display panel 10E of the fifth embodiment shown in FIG. 7, the columnar spacer 25 is formed on the upper electrode 23 that overlaps the scanning line 13 in plan view.

The extending direction of the slit-like opening 24 in the liquid crystal display panel 10E of the fifth embodiment is as follows:
Since it is the same as the liquid crystal display panel 10B of the second embodiment shown in FIG. 4, the rubbing direction is parallel to the signal line 14. Therefore, the region 3 where the rubbing process is not normally performed
2 is formed in parallel with the signal line 14 starting from a columnar spacer. Therefore, the additional light shielding layer 28aE for shielding light from the region 32 where the rubbing process is not normally performed secures an area necessary for area modulation, so that not only the scanning line 13 side but also the signal line 14 side from the TFT side. It is formed so as to extend. Also in the liquid crystal display panel 10E of the fifth embodiment,
The area where the area of the light shielding layer 28 required for area modulation is increased can be used as the additional light shielding layer 28aE, and the area 32 where the rubbing process is not normally performed is completely shielded from light. Will be able to.

[Sixth Embodiment]
Next, a liquid crystal display panel 10F according to a sixth embodiment will be described with reference to FIG. FIG. 8A is a plan view of two pixels of the liquid crystal display panel 10F of the sixth embodiment, and FIG. 8B is a view taken along line VIIIB-VI in FIG. 8A.
It is sectional drawing of an IIB line. The liquid crystal display panel 10F of the sixth embodiment has substantially the same configuration as the liquid crystal display panel 10B of the second embodiment shown in FIG. 4 except that it includes a plurality of types of columnar spacers having different heights. It has become. Therefore, the liquid crystal display panel 10 of the sixth embodiment.
In F, the same reference numerals are given to parts having the same configuration as the liquid crystal display panel 10B of the second embodiment, or some reference numerals are deleted, and the reference numerals having the subscript “B” are subscripts. Is replaced with “F”, and detailed description thereof is omitted.

As shown in FIG. 8, in the liquid crystal display panel 10F of the sixth embodiment, the columnar spacer 25 of the liquid crystal display panel 10B of the second embodiment is used as the columnar spacer formed on the array substrate AR.
In addition to the main columnar spacer 25a having the same configuration as the above, a sub columnar spacer 25b having a height lower than the main columnar spacer 25a by H is provided. That is, the auxiliary columnar spacer 25b
Is formed on the upper electrode 23 that overlaps with the TFT of the array substrate AR of the green sub-pixel 12GF in a plan view in the same process as the main columnar spacer 25a. The auxiliary columnar spacer 25b is also
Similar to the columnar spacer 25, it is covered with a first alignment film 26. The height of the sub-columnar spacer 25b is lower than the height of the columnar spacer 25 by a predetermined height H. Therefore, the first alignment film 26 formed on the surface of the main columnar spacer 25a is in contact with the second alignment film 31 of the color filter substrate CF, but the first alignment film formed on the tip of the sub columnar spacer 25b. 26 is not in contact with the second alignment film 31 of the color filter substrate CF.

In the two-stage columnar spacer having such a configuration, when a large external force exceeding a predetermined value is applied, the color filter substrate CF is deformed and the color filter substrate CF and the sub-columnar spacer 25b come into contact with each other. Further suppression of deformation can be suppressed. When the external force is removed, the sub-columnar spacer 25b is separated from the color filter substrate CF, and the friction against the external force parallel to the color filter substrate CF surface is small. The deviation is easy to return.

As shown in FIG. 8, the length L2 of the region 32b where the rubbing process based on the sub-columnar spacer 25b is not normally performed is shorter than the length L1 of the region 32a where the rubbing process of the main columnar spacer 25a is not normally performed. It has become. The additional light shielding layer 28aFa of the main columnar spacer 25a is also applied to the region 32b where the rubbing process of the sub columnar spacer 25b is not normally performed.
Similarly to the above, an additional light shielding layer 28 a Fb is formed by extending the light shielding layer 28.
In the liquid crystal display panel 10F having a two-stage columnar spacer with a large number of main columnar spacers 25a and sub-columnar spacers 25b, the number of regions in which the rubbing process is not normally performed is more than when one columnar spacer is provided for each of the plurality of pixels. However, large deformation of the color filter substrate CF can be suppressed even when a large external force is applied. In addition, also in the liquid crystal display panel 10F of the sixth embodiment, the additional area of the light shielding layer 28aFa and 28aFb can be used as an area where the area of the light shielding layer 28 required for area modulation is increased. At the same time, the regions 32a and 32b where the rubbing process is not normally performed can be completely shielded from light.

As shown in the liquid crystal display panels 10A to 10F of the first to sixth embodiments described above, the formation positions of the regions 32, 32a and 32b where the rubbing process is not normally performed vary depending on the direction of the rubbing process. , Additional light shielding layers 28aA-28aE, 28aFa and 2
8aFb is formed corresponding to the direction of the rubbing process. In the case of an ECB mode liquid crystal display panel, the rubbing process direction is set to 45 degrees with respect to the polarization direction of the polarizing plate, so that the rubbing process is performed as in the liquid crystal display panel 10C of the third embodiment. The region where the normal operation is not performed occurs in a direction inclined with respect to the scanning line.

In addition, although the additional light shielding layer formed in each embodiment mentioned above showed the example formed by extending the light shielding layer 28 formed in the color filter substrate CF, it is not restricted to this, Additional light shielding layer was shown. The layer may be formed as an isolated light shielding layer separated from the light shielding layer 28. In addition, although the liquid crystal display panel described above is one that operates in the FFS mode, it can also be applied to a liquid crystal display panel that uses other rubbing processing steps such as a TN mode, an IPS mode, and an ECB mode. . In each of the above embodiments, the columnar spacer 25 is formed on the array substrate AR side. However, the present invention can be similarly applied to the case where the columnar spacer 25 is formed on the color filter substrate CF side.

10A to 10F ... Liquid crystal display panel 11A to 11 ... 1 pixel 12RA to 12RF: (red) sub-pixel 12GA to 12GF: (green) sub-pixel 12BA to 12BF: (blue)
Sub-pixel 13 ... scanning line 14 ... signal line 15 ... transparent substrate 16 ... gate insulating film 17 ...
Semiconductor layer 18 ... Passivation film 19 ... Interlayer resin film 20 ... Lower electrode 21 ... Contact hole 22 ... Interelectrode insulating film 23 ... Upper electrode 24 ... Slit-like opening 25 ... Columnar spacer 25a ... Main columnar spacer 25b ... Sub-columnar spacer 26 ... Alignment film 27
... Transparent substrate 28 ... Light shielding layer 28aA to 28aE, 28aFa, 28aFb: Additional light shielding layer 29 ... Color filter layer 30 ... Overcoat layer 31 ... Alignment film 32, 32a
32b: Area where rubbing treatment is not normally performed AR ... Array substrate CF ... Color filter substrate D ... Drain electrode G ... Gate electrode LC ... Liquid crystal layer S ... Source electrode TF
T ... Thin film transistor

Claims (5)

A first substrate and a second substrate disposed opposite to each other with a liquid crystal layer interposed therebetween;
The first substrate includes a plurality of scanning lines and signal lines formed so as to intersect with each other while being insulated from each other, and a pixel electrode formed for each sub-pixel partitioned by the scanning lines and signal lines. ,
In the second substrate,
A light shielding layer formed so as to overlap with the scanning line and the signal line in plan view, and a color filter layer formed for each sub-pixel partitioned by the scanning line and the signal line,
A rubbing alignment film is formed on the surface of the first substrate and the second substrate on the liquid crystal layer side, and a columnar spacer is formed on at least one of the first substrate and the second substrate. A liquid crystal display panel in which one pixel is composed of a plurality of sub-pixels having the color filter layer,
The aperture ratio of one or more subpixels in the one pixel is reduced by making the area of the light shielding layer wider than the subpixels of other colors,
The area where the area of the light shielding layer is widened overlaps with an area where the rubbing process is not performed normally, which is located downstream in the rubbing process direction starting from the columnar spacer in plan view. LCD display panel. The liquid crystal display panel according to claim 1, wherein the color filter layer includes red, green, and blue color filter layers, and the sub-pixel having a small aperture ratio includes a green sub-pixel. The shape of the light-shielding region that covers the region where the rubbing process is not normally performed is substantially the same as the projected shape when the columnar spacer is projected at a predetermined elevation angle in the rubbing process direction. The liquid crystal display panel according to claim 1. The shape of the light shielding area covering the area where the rubbing process is not normally performed is a square shape, and the width and length are the widths when the columnar spacer is projected at a predetermined elevation angle in the rubbing process direction. The liquid crystal display panel according to claim 1, wherein the liquid crystal display panel is longer than the length. The liquid crystal display panel according to claim 1, wherein the columnar spacer includes a mixture of a high height and a low height.

Images