JP4477862B2 - High-quality liquid crystal display - Google Patents

Description

  The present invention relates to a liquid crystal display excellent in display quality with improved brightness unevenness and gravity unevenness.

  In the liquid crystal display, the array substrate and the color filter substrate face each other, and liquid crystal is filled between the substrates. In the liquid crystal display, the molecular arrangement of the liquid crystal is electrically controlled by the array substrate, and display is performed by selectively changing the amount of backlight light transmitted through the color filter substrate.

  FIG. 7 is an example of a cross-sectional view of a liquid crystal display. The liquid crystal display 10 includes an array substrate 12, a color filter substrate 14 facing the array substrate 12 with a constant cell gap, and a plurality of posts that hold the cell gap between the array substrate 12 and the color filter substrate 14 constant. The spacer 16 includes an alignment film 18 formed on the surface of the array substrate 12, the color filter substrate 14, and the post spacer 16.

  Liquid crystal 20 is injected into the display area between the array substrate 12 and the color filter substrate 14, and the substrates 12 and 14 are sealed by applying a pressure sealing load to adjust the cell gap. The polarizing plate 22 is provided on the side of the substrates 12 and 14 that is not in contact with the liquid crystal 20, and a black matrix 24 is formed in the color filter substrate 14 to shield the boundary between pixels.

  The post spacer 16 is formed by, for example, laminating an epoxy or acrylic resin with a uniform thickness on the array substrate 12 or the color filter substrate 14 and patterning it by photolithography. Assuming that the display area is an area where an image is actually displayed in the entire display and the opening is a portion where light can actually be transmitted within the display area, the post spacer 16 avoids the opening and overlaps with the black matrix 24. It is preferably formed in the non-opening. This is because when the post spacer 16 is formed in the opening, a region through which light can be transmitted is reduced, and the orientation of the liquid crystal 20 in the vicinity of the post spacer 16 is disturbed, resulting in a reduction in display quality such as luminance unevenness.

Further, the area occupation ratio S, which is the ratio of the area occupied by the post spacer 16 in the display area, is defined by the following equation.

  Here, the side wall portion of the post spacer 16 is not etched in a linear shape as shown in FIG. 7, but is usually formed in an irregular shape as shown in FIG. Therefore, the dimensions of the upper base of the post spacer 16 are preferably defined as follows using FIG. 8 (see Patent Document 2). First, a tangent line 112 is drawn on the upper base 110 of the post spacer 16, and then the length of one side of the lower base 114 in the same direction as the tangent line 112 is D. Next, as the distance H between the tangent 112 of the lower base 114 and the upper base 110 of the post spacer 16, a height obtained by multiplying the height H by a constant C less than 1, for example, 0.9 is the height of the upper base from the substrate 120. As (C × H), a line X parallel to the substrate 120 is drawn at that position, and the distance between the intersecting points of the line X and the side surface 118 of the post spacer 16 is defined as the dimension of the upper base. Accordingly, the ratio of the upper base area Sx to the lower base area per post spacer in the display area of the liquid crystal display is substantially the square ratio of the upper base dimension and the lower base dimension D in the definition.

  Therefore, as is clear from Equation 1, there are two means for reducing the area occupancy S in a certain liquid crystal display (display area area Saa constant). One is to reduce Sx, and the other is to reduce Nsx.

  On the other hand, if the area occupancy S of the post spacer 16 is reduced, the cell load resistance becomes weak, and there is a problem that the liquid crystal display 10 is easily broken when an external load is applied. Further, if the cell load resistance is not sufficiently strong, when the external load is applied and the post spacer 16 is plastically deformed by a certain amount or more, the plastic deformation is recognized as gap unevenness on the liquid crystal display 10.

  In addition to the gap unevenness due to the plastic deformation of the post spacer 16, the brightness unevenness, the gravity unevenness, etc. can be considered as the cause of the deterioration of the display quality of the liquid crystal display 10.

  Luminance unevenness refers to a phenomenon in which, for example, stress is applied to a glass substrate, distortion occurs, and birefringence is locally generated, thereby causing light leakage and being recognized as luminance unevenness as a whole.

  Gravity unevenness means that when the liquid crystal display is held at a high temperature in a standing state, the thermal expansion of the liquid crystal exceeds the range of elastic deformation during pressure sealing of the post spacer. A phenomenon in which liquid crystal accumulates in the lower part due to gravity and is recognized as gap unevenness.

  Document 1 discloses a liquid crystal panel using a post spacer having an elastic deformation rate [(elastic deformation / total deformation) × 100] of 60% or more with respect to a pressure load of 2.0 GPa at room temperature. According to Document 1, the post spacer of the present invention has sufficient strength that is difficult to be plastically deformed with respect to pressure load, and flexibility that can follow liquid crystal shrinkage and expansion within the operating environment temperature. Therefore, when the array substrate and the color filter substrate are bonded together, pressure unevenness is alleviated or absorbed to make the load uniform throughout the substrate and prevent gap unevenness from occurring. The cell gap can be maintained at a predetermined distance. In addition, the completed liquid crystal panel can prevent the display unevenness because the cell gap can be restored to its original state even if the external liquid crystal panel is subjected to an external force such as an impact or a pressing force, even if it is temporarily distorted. Furthermore, since the liquid crystal can follow the thermal contraction or expansion in a wide temperature range including room temperature, the generation of bubbles can be prevented.

  However, in the invention of Literature 1, the relationship between the display unevenness of gap unevenness, luminance unevenness, and gravity unevenness due to cell load resistance and the elastic deformation rate E, plastic deformation rate P, and area occupation rate S of the post spacer is unknown. It is not clear how much pressure sealing load can be applied to manufacture a liquid crystal display in which each display unevenness is suppressed. In the following description, the elastic deformation rate E and the plastic deformation rate P of the post spacer are as follows: elastic deformation rate E = elastic deformation amount / original height of post spacer, plastic deformation rate P = plastic deformation amount / post spacer Original height, defined as a percentage (%).

JP 2003-241199 A ([23] to [31]) JP 2000-321580 A ([24] to [26])

  Accordingly, an object of the present invention is to provide a liquid crystal display capable of improving luminance unevenness and gravity unevenness without deteriorating cell load resistance. It is another object of the present invention to provide a liquid crystal display design method capable of freely selecting which effect of improvement in luminance unevenness or gravity unevenness is to be exerted freely using a pressure sealing load as a parameter.

  The liquid crystal display according to the present invention is formed on an array substrate, a color filter substrate facing the array substrate while maintaining a certain cell gap, the color filter substrate or the array substrate, and the color filter substrate and the array substrate. And a post spacer that supports the cell substrate with a constant cell gap, and a pressure sealing load applied to the array substrate and the color filter substrate, and the liquid crystal layer pressure sealed between the substrates The area occupancy S of the post spacer is the sum of the upper area of the post spacer in the display area / the area of the display area is 0.075% or less, and the post spacer has 4 GPa When the pressure is applied, the elastic deformation rate E of the post spacer is greater than 24.0% in a normal temperature environment, and the plastic deformation Rate P satisfies less than 14.9%. Here, the ratio of one side or diameter of the upper base of the post spacer to one side or diameter of the lower base is 50 to 100%, more preferably 50 to 90%. In FIG. 8, the ratio of the upper base to the lower base varies depending on the value of the constant C applied to the height H of the upper base 110. The above ranges of 50 to 100% and 50 to 90% have a constant C of 0.9. This is the value when set to.

  The liquid crystal display of the present invention can adjust the unevenness in brightness and the unevenness of gravity, which are obstructive factors in the display quality of the liquid crystal display, by changing the pressure sealing load applied to the array substrate and the color filter substrate.

  In the liquid crystal display of the present invention, the pressure sealing load received by the array substrate and the color filter substrate by the pressure sealing load may be 25 KPa or less.

  The liquid crystal display of the present invention can improve brightness unevenness and gravity unevenness without deteriorating cell load resistance. Moreover, according to the design method of the liquid crystal display of the present invention, it is possible to freely select which one of the effects of improvement of luminance unevenness or gravity unevenness is to be exhibited, using the pressure sealing load as a parameter.

In order to solve the problems of the invention, first, gap unevenness due to cell load resistance, luminance unevenness and gravity unevenness, post-spacer area occupancy S, elastic deformation rate E and plastic deformation rate P, and pressure sealing load, The relationship was investigated by experiment. Here, the elastic deformation rate E and the plastic deformation rate P are representative values when a load of 200 mN (pressure of 4 GPa) is applied to one column (area Sx = 50 μm ^2, height 4.5 μm) at room temperature. It shall mean elastic deformation rate and plastic deformation rate.

  The gap unevenness due to the cell load tolerance occurs due to distortion generated on the liquid crystal display 10 as shown in FIG. 2B when a load is applied to the display surface as shown in FIG. If the cell load resistance is not sufficiently strong, when the external load is applied and the post spacer 16 is plastically deformed by a certain amount or more, the plastic deformation is recognized as gap unevenness on the liquid crystal display 10.

  There are the following two means for improving the cell load resistance. That is, (A1) increase the area occupation ratio S of the post spacer, or (A2) use a material having a large elastic deformation rate E and a small plastic deformation rate P for the post spacer. By using the means (A1) or (A2), gap unevenness due to cell load resistance could be suppressed.

  As shown in FIG. 3A, the luminance unevenness generally refers to a phenomenon in which, for example, stress is applied to a glass substrate and distortion occurs, and birefringence is locally generated, thereby causing light leakage, and thus being recognized as luminance unevenness as a whole. However, in this embodiment, the liquid crystal display is a normally black display that does not transmit light as shown in FIG. 3B when no voltage is applied between both electrodes. Hereinafter, in this specification, luminance unevenness refers to light unevenness (referred to as L0 unevenness) that appears on the display surface when a voltage is not applied between both electrodes.

  As an element that reduces the strain of the glass subjected to stress and releases the strain when the stress is released, (B1) reduce the area occupancy S of the post spacer 16, and (B2) reduce the pressure sealing load. The two elements are the main ones.

  As described above, gravity unevenness means that when the liquid crystal display is held up at a high temperature and the thermal expansion of the liquid crystal exceeds the range of elastic deformation during pressure sealing of the post spacer, This is a phenomenon in which the liquid crystal accumulates in the lower part due to gravity and is recognized as gap unevenness. FIGS. 4A to 4C illustrate the mechanism of occurrence of gravity unevenness.

  When the liquid crystal display shown in FIG. 4A in which the liquid crystal is pressure-sealed is heated, the color filter substrate is peeled off from the post spacer by the thermal expansion of the liquid crystal as shown in FIG. 4B. When the liquid crystal display is held perpendicular to the ground in the state of FIG. 4B, the liquid crystal accumulates in the lower part of the liquid crystal cell due to the gravitational action, and gravity unevenness occurs in the lower part of the display.

  In order to improve gravity unevenness, it is effective to (C1) increase the pressure sealing load and (C2) to employ a material having a large elastic deformation rate E and a small plastic deformation rate P for the post spacer 16. .

  In consideration of the above results, in the present invention, as a means for improving the cell load resistance, the above-described means (A2) is used which uses a material having a large elastic deformation rate E and a small plastic deformation rate P for the post spacer 16. Gravity unevenness can also be improved from this result (C2).

  On the other hand, the area occupancy S was made as small as possible. That is, in the present invention, the area occupancy S of the post spacer 16 is reduced contrary to (A1), but the means of (A2) is adopted to make the cell load resistance equal to the current level. This is because reducing the area occupancy S of the post spacer 16 greatly contributes to improvement in luminance unevenness as shown in (B1). At the same time, the contribution of (C2) to the improvement of gravity unevenness can be strengthened.

  Further, when the pressure sealing load is reduced, the luminance unevenness is suppressed from (B2), but the conflicting result that the gravity unevenness is increased from (C1) was confirmed.

  The liquid crystal display of the present invention obtained on the basis of the above considerations has a post-spacer area occupancy ratio [the total of the post spacer upper bottom area in the display area / the area of the display area] of 0.075% or less. When a pressure of 4 GPa is applied to the post spacer, the elastic deformation rate of the post spacer is greater than 24.0% and the plastic deformation rate is less than 14.9% in a normal temperature environment. The liquid crystal display satisfies the diagram shown in (b). Note that the normal temperature environment is a temperature in a living environment that humans can experience daily, and may include at least 0 to 40 degrees Celsius.

  FIG. 1B is a diagram showing the relationship between the luminance unevenness and load resistance of the liquid crystal display of the present invention, the pressure sealing load at the time of liquid crystal sealing, the area occupation ratio S of the post spacer 16, the luminance unevenness, and the gravity unevenness. . The liquid crystal display used for preparing this diagram is a liquid crystal display having a display area size of 43 cm × 27 cm and a cell gap of 3.4 μm. In addition, the liquid crystal display is an IPS (In-Plane Switching) method, and the arrangement of liquid crystal molecules changes in the substrate plane by the on / off of an electric field along the substrate.

  In FIG. 1B, the horizontal axis represents the pressure sealing load (Kgf) applied to both substrates 12 and 14 when the liquid crystal 20 is sealed between the array substrate 12 and the color filter substrate 14, and the vertical axis represents the post spacer. An area occupancy of 16 is represented. For convenience, when the area occupancy S of the post spacer 16 according to the above definition is 0.125%, the column occupancy shown on the vertical axis in FIG. Yes. As described below, in the liquid crystal display of the conventional example, the normalized column occupation ratio is 100% (area occupation ratio S = 0.125%). Kgf is an engineering unit, and 1 Kgf = 9.8 N.

  The straight line increasing with the pressure sealing load is the limit value line of gravity unevenness, and the straight line decreasing with the pressure sealing load is the limit value line of luminance unevenness. Moreover, the straight line which becomes a fixed value with respect to a pressure sealing load represents the limit value line of load tolerance.

  Here, the limit line of gravity unevenness or brightness unevenness is a line where the maximum gravity unevenness or brightness unevenness that can be allowed when a liquid crystal display is commercialized can occur on the display, and the area below both lines is the liquid crystal This is an area where displays can be commercialized. That is, as described above, when the pressure sealing load is reduced, the luminance unevenness is suppressed, but the gravity unevenness increases.

  Further, the load resistance limit value line is a line indicating the minimum load resistance that the liquid crystal display should have in commercialization, and the area above the limit value line is an area where the liquid crystal display can be commercialized. The load resistance limit value line is shown in FIG. 1B when the pressure sealing load applied to the array substrate and the color filter substrate is about 25 KPa or less (in this embodiment, the pressure sealing load is 300 kgf). Thus, it is substantially parallel to the horizontal axis (pressure sealing load). As described above, the liquid crystal display according to this embodiment prevents the luminance unevenness (L0 unevenness) and improves the gravity unevenness, so that the area occupancy S is 0.075% or less (the normalized column occupancy is about 60% or less). And On the other hand, in order to compensate for the shortage of cell load resistance due to the reduction of the area occupancy S, a means of using a material having a large elastic deformation rate E and a small plastic deformation rate P for the post spacer 16 was used. The post spacer 16 used in the liquid crystal display of this embodiment has an elastic deformation rate of greater than 24.0% and a plastic deformation rate of less than 14.9% when a pressure of 4 GPa is applied.

  As can be seen from FIG. 1B, the liquid crystal display of the present invention changes the pressure sealing load applied to the array substrate 12 and the color filter substrate 14 to change the luminance which is an impediment to the display quality of the liquid crystal display. The ratio of unevenness and unevenness in gravity can be adjusted.

  In Examples 1 to 4 below, the liquid crystal display of the present invention is compared with the liquid crystal display of the conventional example, and the diagram shown in FIG. For convenience, the post spacer used in the liquid crystal display of the present invention is referred to as a highly elastic column, and the post spacer constituting the conventional liquid crystal display is referred to as an Rtn column. As described above, the normalized column occupation ratio shown in FIG. 1B is re-standardized so that the normalized column occupation ratio becomes 100% when the area occupation ratio S of the Rtn column is 0.125%. Yes.

  In Examples 1 to 4, the following comparisons were made. (1) In Example 1, the elastic deformation rate E and the plastic deformation rate P of the Rtn column and the highly elastic column were compared. (2) In Example 2, the cell load resistance of the Rtn column and the highly elastic column was compared. (3) In Example 3, the luminance unevenness of the Rtn column and the highly elastic column was compared. (4) In Example 4, the gravity unevenness of the Rtn column and the highly elastic column was compared.

FIG. 5 is a graph showing the relationship between the elastic deformation rate E and the plastic deformation rate P and the load related to one column of the Rtn column and the highly elastic column having an area Sx = 50 μm ² . The elastic deformation rate E (%) and the plastic deformation rate P (%) are respectively the elastic deformation rate and the plastic deformation when a load of 200 mN is applied to one column (area Sx = 50 μm ² , height = 4.5 μm). Rate.

  Both the Rtn column and the highly elastic column in the present embodiment are formed by photolithography. That is, a post spacer resist is applied to a glass substrate on which a black matrix, a color resist layer and an overcoat layer are formed, exposed through a photomask, and further developed and baked to form a post spacer pattern. It was done. Here, the high elastic column is formed of an existing photo-curing resin that has higher elasticity and lower plasticity than the resin used for forming the Rtn column.

  From FIG. 5, it can be seen that the highly elastic column constituting the liquid crystal display of the present invention has a larger elastic deformation rate and a lower plastic deformation rate than the conventional Rtn column. That is, from the graph of FIG. 5, the high elastic column satisfies both the conditions of elastic deformation rate E> 24.0% and plastic deformation rate P <14.9% when the load applied to one column is 4 GPa. It can be seen that the Rtn column has an elastic deformation rate E = 24.0% and a plastic deformation rate P = 14.9%.

  In this example, when the normalized column occupancy ratio of the Rtn column and the highly elastic column used in Example 1 is changed and a load is applied from above the polarizing plate 22 on the color filter substrate 14, gap unevenness is recognized in the liquid crystal display. Measured pressure.

  As shown in the table of FIG. 6B, the liquid crystal display has a standardized column occupation rate of 100% (area occupation rate S = 0.125%), a 45% Rtn column, and a standardized column occupation rate of 102%, 57. Four types of liquid crystal displays having a post-spacer as a highly elastic column of 100% were used. Each display has a size of 43 cm × 27 cm and a cell gap of 3.4 μm. The pressure at which gap unevenness was recognized on the liquid crystal display when a load was applied in units of 1 (Kgf / 10 mmφ) from above the polarizing plate 22 was measured, and the graph of FIG. 6A was obtained.

From FIG. 6A, the liquid crystal display using the high elasticity column with the standardized column occupancy rate of 102% does not recognize the gap unevenness up to about twice the pressure as compared with the Rtn column with the standardized column occupancy rate of 100%. It was.
If the cell load resistance is not sufficiently strong, an external load is applied and the post spacer is plastically deformed by a certain amount or more, and the plastic deformation is recognized as gap unevenness on the liquid crystal display. Therefore, when the normalized column occupancy is the same, it can be seen that the liquid crystal display using the highly elastic column has a cell load resistance of about twice that of the Rtn column. This is also because the cell load resistance of a liquid crystal display using an Rtn column with a normalized column occupation rate of 100% and a liquid crystal display using a highly elastic column with a normalized column occupation rate of 57% are substantially the same. It is supported.

  According to the present embodiment, the post spacer is made of a material having a high elastic deformation rate E (E> 24.0%) and a small plastic deformation rate P (P <14.9%) (high elastic column). It can be seen that the cell load resistance is more than doubled compared to the post spacer (Rtn pillar). Therefore, even when the area occupancy of the post spacer is reduced to 57% (S = 0.071%), the same cell load resistance as that of the conventional one can be secured. In the liquid crystal display of this embodiment, the area occupancy S that can prevent the luminance unevenness (L0 unevenness) is 0.075% or less (the normalized column occupancy is About 60% or less).

In the present embodiment, an Rtn column (area occupancy S = 0.125%) with a normalized column occupancy rate of 100% and a highly elastic column with a normalized column occupancy rate of 57% (area occupancy S = 0.071%). The brightness unevenness which occurs in the liquid crystal display which uses is compared. As shown in Table 1, the pressure sealing load applied between the array substrate 12 and the color filter substrate 14 when sealing the liquid crystal in the liquid crystal display is 200 (Kgf), and the cell gaps of both liquid crystal displays are substantially the same. It is.

  As an experimental result of this example, in the liquid crystal display using the highly elastic column with 57% normalized column occupancy of the present invention, it was seen in the liquid crystal display using the Rtn column with 100% normalized column occupancy. Almost no luminance unevenness was observed. As described above (B1), the area occupancy S (standardized column occupancy) of the post spacer 16 is approximately halved (0.57 times) from the liquid crystal display of the conventional example, so that the luminance unevenness can be greatly improved. Understood.

  In this example, the standardized column occupancy of the Rtn column and the highly elastic column used in Example 1 was changed, and the pressure sealing load at which gravity unevenness was recognized on the liquid crystal display was measured. Here, the pressure sealing load is a load applied between the array substrate 12 and the color filter substrate 14 when the liquid crystal is sealed in the liquid crystal display as described above. In this example, it was examined whether gravity unevenness was recognized on the liquid crystal display when the pressure sealing load was 150 (Kgf), 200 (Kgf), and 250 (Kgf).

As shown in Table 2, the liquid crystal display used in this example has a normalized column occupancy rate of 100% (area occupancy S = 0.125%), a 45% Rtn column, and a normalized column occupancy rate of 102%. Four types of liquid crystal displays using 57% highly elastic pillars as post spacers. The size of each display is 43 cm × 27 cm. The panel was held vertically at 60 ° C. for about 2 hours, and the degree of gravity unevenness was observed. When standing upright, the short side of the panel was on the bottom.

  According to the present embodiment, it is understood that the gravity unevenness is improved by raising the pressure sealing load. Further, in the liquid crystal display of the present invention configured by arranging highly elastic columns with a normalized column occupancy rate of 57% (area occupancy rate S = 0.071%), the Rtn column is arranged with a normalized column occupancy rate of 100%. Gravity unevenness is greatly improved compared to the conventional liquid crystal display.

  That is, the post spacer is made of a material having a large elastic deformation rate E (E> 24.0%) and a small plastic deformation rate P (P <14.9%) (high elastic column), and the post spacer has an area occupation ratio. By reducing S to about 60% (S <0.075%), gravity unevenness could be greatly improved.

  Finally, in order to more comprehensively understand the results obtained by the above examples and the like, FIG. 1A and FIG. FIG. 1A is a diagram of a liquid crystal display using a conventional Rtn column having a normalized column occupation rate of 100%, and FIG. 1B is a normalized column occupation rate of 57% according to the present invention as described above. It is a diagram about a liquid crystal display using a highly elastic column (area occupancy S = 0.071%). Here, the post spacer (high elastic column) used in the liquid crystal display of the present invention satisfies both the elastic deformation rate E> 24.0% and the plastic deformation rate P <14.9% at the same time. Further, the way to view the diagram FIG. 1B is as described above.

  FIG. 1A shows a luminance unevenness and load resistance of a liquid crystal display using a conventional Rtn column with a normalized column occupation ratio of 100%, a pressure sealing load at the time of liquid crystal sealing, and a normalized column occupation of the post spacer 16. It is a diagram showing the relationship between the rate (corresponding to the area occupancy S), luminance unevenness and gravity unevenness. The liquid crystal display used for preparing this diagram is the same as the display used in FIG. 1B, and is an IPS liquid crystal display having a size of 43 cm × 27 cm and a cell gap of 3.4 μm.

  In FIG. 1A, the horizontal axis is the pressure sealing load (Kgf), the vertical axis is the area occupancy of the post spacer 16, and the straight line increasing with the pressure sealing load is the limit line of gravity unevenness, A straight line that decreases with the pressure sealing load is a limit line of luminance unevenness, which is the same as in FIG. However, the load resistance limit value line is a straight line parallel to the horizontal axis where the normalized column occupancy is about 50% in FIG. 1 (b), whereas in FIG. 1 (a) the normalized column occupancy is It becomes a straight line parallel to the horizontal axis which is 100%. Accordingly, the liquid crystal display of the present invention has sufficient cell load resistance when the normalized column occupation ratio is about 50% or more, whereas the liquid crystal display using the conventional Rtn column has a normalized column occupation ratio of 100. If it is not more than%, the cell load resistance is insufficient and gap unevenness occurs.

  As described above, when a liquid crystal display is commercialized, the display quality related to gravity unevenness and brightness unevenness is guaranteed in the area below the limit value line of gravity unevenness or brightness unevenness, and the display quality related to gap unevenness is guaranteed. This is the area above the limit line of load resistance. In the diagram of FIG. 1A, there is no region where the display quality related to the three unevennesses is guaranteed, whereas in the diagram of FIG. 1B, there is a region where the display quality related to the three unevennesses is satisfied. I understand that.

  In other words, if the liquid crystal display of the conventional example guarantees the display quality related to the gap unevenness, it is necessary to allow either the unevenness of gravity or the unevenness of brightness to occur. However, the area occupancy S of the post spacer 16 of the present invention is 0.075% or less (standardized column occupancy is 60% or less), and the elastic deformation ratio is 24 when a load of 4 GPa is applied to the post spacer 16. A liquid crystal display having a plastic deformation ratio of greater than 0.0% and a plastic deformation rate of less than 14.9% can satisfy the display quality for all the unevenness of gravity, brightness, and gap.

  Further, as can be seen from FIG. 1B, the liquid crystal display of the present invention is an obstacle to the display quality of the liquid crystal display by changing the pressure sealing load applied to the array substrate 12 and the color filter substrate 14. The degree of brightness unevenness and gravity unevenness can be adjusted.

  The liquid crystal display of the present invention has been described above, but the present invention is not limited to the above embodiment. In the above embodiment, the liquid crystal display uses the IPS system, but the liquid crystal display of the present invention may be a liquid crystal display of another system such as a Twisted Nematic (TN) system.

Further, the material of the post spacer constituting the liquid crystal display of the present invention is not limited. The present invention includes all post spacers made of a material having an elastic deformation rate of greater than 24.0% and a plastic deformation rate of less than 14.9% when a pressure of 4 GPa is applied.
Furthermore, the shape of the post spacer is not particularly limited. As described above, the ratio of one side or diameter of the upper base to one side or diameter of the lower base is preferably 50 to 90%.

  In addition, the present invention can be carried out in a mode in which various improvements, modifications, and changes are added based on the knowledge of those skilled in the art without departing from the gist thereof.

  It can be used for all types of liquid crystal televisions, personal computer displays, and other IPS liquid crystal displays.

(A) It is a diagram showing the relationship between the luminance unevenness and load tolerance of the conventional liquid crystal display, the pressure sealing load at the time of liquid crystal sealing, the area occupation ratio S of the post spacer 16, the luminance unevenness, and the gravity unevenness. (B) It is a diagram showing the relationship between the luminance unevenness and load tolerance of the liquid crystal display of the present invention, the pressure sealing load at the time of liquid crystal sealing, the area occupation ratio S of the post spacer 16, the luminance unevenness and the gravity unevenness. (A) It is sectional drawing of the liquid crystal display of the state which does not apply a load. (B) It is sectional drawing of the liquid crystal display which applied the load to the display surface and generate | occur | produced distortion. (A) It is a perspective view of the liquid crystal display which the birefringence produced locally by the rotation of the elliptical polarization axis of the liquid crystal layer, and the light omission occurred. (B) It is a perspective view of the liquid crystal display in the state whose elliptical polarization axis of a liquid crystal layer is normal. (A) It is sectional drawing of the liquid crystal display at the time of pressure-sealing a liquid crystal. (B) It is sectional drawing of the liquid crystal display of the state from which the color filter board | substrate peeled from the post spacer by the thermal expansion of the liquid crystal. (C) It is sectional drawing of the liquid crystal display with which the liquid crystal collected by the gravity action at the lower part of the liquid crystal cell, and the gravity nonuniformity generate | occur | produced. It is a graph showing the relationship between the elastic deformation rate E (%) and the plastic deformation rate P (%) of the Rtn column and the highly elastic column and the pressure (GPa) applied to one column. (A) It is a histogram showing the pressure by which a liquid crystal display recognizes gap nonuniformity when a load is applied from the color filter substrate to a plurality of Rtn columns and highly elastic columns having different normalized column occupation ratios. (B) It is a table | surface showing the mode of the gap nonuniformity which arises in a liquid crystal display, when a load is applied from the color filter board | substrate with respect to several Rtn pillars and high elastic pillars from which a normalization pillar occupation rate differs. It is sectional drawing of a liquid crystal display. It is sectional drawing of a post spacer.

Explanation of symbols

10: liquid crystal display 12: array substrate 14: color filter substrate 16: post spacer 18: alignment film 20: liquid crystal 22: polarizing plate 24: black matrix 110: upper base 112: tangent line of upper base 114: lower base 118: side surface 120 :substrate

Claims (1)

An array substrate;
A color filter substrate facing the array substrate while maintaining a certain cell gap;
A post spacer formed on the color filter substrate or the array substrate and supporting the color filter substrate and the array substrate while maintaining a constant cell gap;
Applying a pressure sealing load to the array substrate and the color filter substrate, a liquid crystal layer pressure-sealed between the substrates,
A liquid crystal display including
The area occupancy of the post spacer [the total area of the post spacer upper base in the display area / the area of the display area] is 0.075% or less,
When pressure was applied 4GPa the post spacer, elastic deformation rate of the post spacer is greater than 24.0% in a normal temperature environment, and the plastic deformation ratio is less than less than 14.9%,
A liquid crystal display , wherein a pressure sealing load applied to the array substrate and the color filter substrate is 200 to 300 kgf .

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