TWI251106B - Image display device - Google Patents

Abstract

To realize an image display device capable of holding a cell gap between two substrates in a fixed length, thereby preventing the occurrence of luminance unevenness in an image display region. The cell gap in the boundary region between a central region and an edge side part of a pixel part after two substrates are stuck can be fixedly held by controlling the sectional surface area and/or the disposing interval of columnar spacers on the edge side part among the columnar spacers formed on one substrate of two substrates of the image display device before the two substrates are stuck. As a result, the image display device preventing luminance unevenness of the image display region can be realized and an increase of manufacturing costs can be suppressed since the columnar spacers are formed by using a single photo mask.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device in which an image display material is injected between two substrates, and a column spacer is used to maintain a fixed distance of liquid crystal cells. Prior Art Image display devices are electronic systems that convert electrical signals into visual images that can be directly interpreted by humans as electronic optical devices. Such a display device is most widely used as a liquid crystal display device (Liquid Crystal Display: LCD), and other plasma display panels (PDP) and electroluminescence (Electro Luminescence EL) have been developed. In addition, the field emission display device (FED) and the variable lens element (Deformable Mirror Device · DMD) that controls the operation of the reflective lens have been rapidly popularized. Among them, a liquid crystal display device is a display device in which a liquid crystal technology using a liquid crystal optical property in which an electric field causes a molecular arrangement is changed and a semiconductor technology capable of forming a fine pattern is used as a synonym for a flat panel display device. In a liquid crystal display device, a thin film transistor (TFT-LCD) has various advantages such as low power consumption, low voltage driving force, thinness, and light weight. The liquid crystal display device is formed by laminating two substrates. In order to maintain a uniform cell gap and prevent uneven brightness, it is necessary to provide a column spacer. Here, the cell gap refers to the thickness of the liquid crystal layer. Figure 4 is a cross-sectional view showing a liquid crystal display device of the prior art. Figure 4 (a) is attached to the cover

O:\85\85611.DOC 1251106 A cross-sectional view of the cap layer spacer 104 formed on the cap layer 103 of the black matrix layer 102 on the board 101. Fig. 4(b) is a cross-sectional view of the liquid crystal display device in which the counter substrate 1〇1 and the array substrate 106 are bonded to each other and the liquid crystal is main. In the figure, the pixel portion ill refers to the area where the image is displayed, and the edge portion 112 refers to the area where the image display area enters the mountain seal. In the method of manufacturing a liquid crystal display device, a transparent electrode and an alignment film are formed after a liquid crystal driving element such as a thin film transistor, a color filter or the like is provided on a pair of transparent, opaque, and substrate. Next, the column spacers 104 are formed on one of the substrate faces. FIG. 4 is a case where the spacer spacer 104 is formed on the opposite substrate 1〇1. The columnar spacers 1 to 4 are formed by applying a photosensitive resin material such as an acrylic resin to the entire surface of the substrate, and exposing it through a mask exposure & lithography step. Here, in the liquid crystal display device according to the prior art, in order to make the cell gap uniform, the columnar spacers 104 of the same shape are uniformly disposed on the pixel portion 111 and the edge 4 112. That is, the cross-sectional area of the columnar spacer 104 is both S4 in the pixel portion 111 and the edge portion 112, and the arrangement interval in one direction of the gate mesh member 1 〇4 is in the pixel portion 111 and the edge portion U2. a, the height is formed in this way. After the columnar spacers 104 are formed, the pair of substrates are stacked by the columnar spacers 1〇4 to seal the liquid crystal material into the gap defined by the columnar spacers 4, and the U-shaped layer 4 is formed. The liquid crystal display device shown in the drawings (for example, refer to Patent Document 1 and Patent Document 2). JP-A-2002-182222 (P.5, 1)

O:\85\85611.DOC l25ll〇6 DISCLOSURE OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION However, as shown in Fig. 4(a), irregularities are actually generated on the surface of the substrate 101 due to various layer structures. Therefore, the columnar spacer 104 having a uniform height is disposed on the uneven surface, and the cell gap has a positional dependency, which causes a problem of uneven brightness. In the case where the columnar spacer 104 formed on the cover layer 1 () 3 is formed in a lithography step, the height of the columnar spacer 1 4 itself after the lithography step becomes at the pixel portion ln and the edge portion 112. The length of the big text is equal. Here, there is a difference in the area of the black matrix layer 102 in the pixel portion 丨丨丨 and the edge portion 丨1 2 . Therefore, the covering layer 103 covering the black matrix layer 1〇2 produces a film thickness difference hc. On the other hand, since the columnar spacers 1 and 4 are uniformly arranged by the pixel portion lu and the edge portion 112, the columnar spacers 1 to 4 are compressed to the same extent regardless of the arrangement region by the pressure applied during the bonding. Therefore, as shown in Fig. 4(a), the position of the upper portion of the columnar spacer ι4 of the edge portion 112 is higher than the position of the upper portion of the columnar spacer 丨〇4 of the pixel shaft 111. In other words, after the two substrates are bonded, the position of the upper portion of the columnar spacer 丨〇4 of the edge portion 丨丨2 is higher than that of the pixel SHA 111. As shown in FIG. 4(b), the array substrate 106 is attached to the pixel SHA 111. The edge portion 112 is bonded only in a state of ΔX deformation. This deformation occurs as a result of the cell gap d4 of the region B of the boundary region between the pixel portion 111 and the edge portion 112 being thickened as compared with the cell gap d3 at the central portion of the pixel portion lu. Since the brightness of the liquid crystal layer 105 is thickened as the thickness of the liquid crystal layer 105 is increased, the luminance of the area B of Fig. 4(b) is brighter than the central area of the pixel portion 111. Therefore, as shown in Fig. 5, since the brightness of the area B of the peripheral portion of the pixel portion 111 is enhanced, uneven brightness is generated.

O:\85\85611.DOC 1251106 (_), resulting in deterioration of the image quality of the liquid crystal display device. Especially in the case of monochrome writing, the liquid crystal-the pixel portion and the edge portion of the device clearly show uneven brightness. In order to eliminate the upper substrate 1Gq_Ax, the secondary lithography of the (four) row is performed so that the height of the column spacer of the edge portion 112 is lower than the height of the column spacer of the image (4) (1). That is, the column spacers of different heights are arranged in each region to absorb the fluctuation of the cell gap at the end of the pixel portion (1), and the cell gap of the hook portion is realized along the entire pixel portion 111 to suppress the occurrence of luminance unevenness. Specifically, by using different masks, the lithography steps are performed on the image (4) (1) and the edge portion 112, respectively, to form column spacers of different heights. Fig. 6 is a graph showing the occurrence of a luminance unevenness in the peripheral portion of the pixel portion of the liquid crystal display device when the height difference between the pixel spacers of the pixel portion and the edge portion is set in the second lithography step. As shown in Fig. 6, when the height difference between the pixel portion and the edge H-shaped spacer is IWm, the pixel portion and the edge i are not seen. Unevenness occurs. Further, when the difference between the gate portions of the pixel portion and the edge portion is 0.5 to i.5 #m, the brightness of the pixel portion and the edge portion can be suppressed to the extent that the pattern is visually recognized. Therefore, by performing the second lithography step 7, the height of each column spacer of the pixel and the edge is set to a difference of ~5~u" : to compensate for the cell gap difference, and the pixel portion and the edge portion can be suppressed. However, when the method of the second lithography step is carried out, the step of forming the second ruthenium spacer is required, which leads to an increase in manufacturing cost and a decrease in productivity, which is not appropriate. AI & change the i-item in the bottom structure of the columnar spacer and the edge of the columnar spacer, and do not open the column spacers of the formation, the interest, the y into the 4 sides, and the 彖 之, to adjust the sealing portion of the edge洚T 1 asks about the technology. Due to the shape of the original column spacer

O:\85\85611.DOC 1251106 The arrangement of the seal and the seal is carried out in other steps, so the use of this method does not lead to an increase in manufacturing costs and a decrease in productivity. However, the columnar spacer does not form a columnar spacer display device, and when the glass material of the substrate is expanded at a high temperature, it is particularly difficult to suppress the glass deformation of the edge portion. Therefore, since the edge is sharp (the substrate interval fluctuates, the boundary between the central portion and the edge portion of the pixel portion is different between the cells and the gap, and the luminance unevenness at the edge portion of the pixel portion cannot be completely eliminated. A disadvantage of the prior art is to provide an image display device which does not increase the negative # in the manufacturing step, and maintains the single-turn gap <uniformity' to suppress the occurrence of luminance unevenness at the edge portion of the pixel portion. The method for solving the problem is that the image display device of the patents 1 & ^1 has a column member and is held on the substrate of the substrate - the user of the fixed cell is characterized in that Before the two substrates are bonded together, the columnar spacers are formed. The cross-sectional area of the columnar spacers at the edge portion and/or the cross-sectional area or/and the arrangement interval of the columnar spacers between the inter-position and the pixel portion are mutually The value of the difference is such that the cell gap between the central portion of the pixel portion after the bonding and the end portion of the pixel portion is uniformized. According to the invention of claim i of the patent scope, the image display device "pixel" can be eliminated. The brightness of the portion and the edge portion is uneven. In addition, it is possible to suppress the manufacturing cost & the manufacture of the image display device. A patented image of the image display device according to item 2 of the second aspect is attached to the above-mentioned edge. The columnar spacer is the same height as the columnar spacer of the symplectic portion.

The image display device according to claim 3, wherein the cross-sectional area of the columnar spacer at the edge portion is larger than the columnar portion of the pixel portion before the substrate is bonded to the substrate. The cross-sectional area of the spacer is small. In the image display device according to the fourth aspect of the invention, the columnar spacer of the edge portion is disposed wider than the columnar spacer of the pixel portion before the substrate is bonded to the substrate. In the image display device according to the fifth aspect of the invention, the columnar member is formed of a photosensitive material, and the columnar spacer of the edge portion and the columnar spacer of the pixel portion are subjected to the same lithography step. form. An image display device according to claim 6 is characterized in that a liquid crystal layer is formed between the two substrates. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an image display device and a manufacturer thereof according to the present invention will be described in detail with reference to the accompanying drawings. The invention will now be described by way of example for use in a liquid crystal display device. Ben Maoming is not subject to this greed. The same part is attached to the same symbol in the figure. In addition, the figure is a mode, please note that the thickness and width of each layer, the ratio of each layer, etc. are different from the actual structure. The illustrations also contain parts of each other that differ in size and proportion. First Embodiment A liquid crystal display device according to a first embodiment will be described. First Embodiment 仂 < Liquid Egg _ TF device has a configuration in which the uniformity of the cell gap of the image-display region is maintained by having different cross-sections per column spacer. Hereinafter, a specific configuration will be described with reference to FIGS. 1 and 2.

O:\85\85611.DOC -10- 1251106 Fig. 1 is a liquid crystal display device of the first embodiment. The liquid crystal display device is composed of the pixel portion 2 and the edge portion 3. Fig. 2(a) is a view showing a columnar spacer 14 formed on the cover layer 13 of the black matrix layer 12 covering the opposite substrate U in a line region corresponding to the line a_a of Fig. 2, in a state before the array substrate 16 is bonded. Further, Fig. 2(b) is a cross-sectional view taken along line A of Fig. 1 in which the counter substrate n and the array substrate 16 are bonded and vacuum-injected into a liquid crystal. As shown in Fig. 2(b), the liquid crystal display device of the first embodiment is formed on the opposite substrate 11, and the black matrix layer 12, the cover layer 13, and the columnar spacers 14 are sequentially formed, and the columnar spacers 14 are used. The array substrate 16 is configured with a certain cell gap. The liquid crystal layer 15 is formed by bonding the counter substrate 1 and the array substrate 16 by the columnar spacers 14, and injecting liquid crystal into the pitch. The column «spacer i 4 is coated with a photosensitive resin, for example, an acrylic resin, and is formed by a lithography step. The lithography step is carried out by a method of hardening the applied photosensitive resin 、 and developing the image after exposure. As shown in Fig. 2 (4), the height of the columnar spacers 14 from the cover portion 13 of the pixel portion 2 and the edge portion 3 is ^. It is not necessary to divide into a secondary lithography step, which is formed by a lithography step. Further, as shown in FIG. 2 (4), in the liquid crystal display device according to the first embodiment, at least in the direction of the front substrate u and the array substrate 16, the columnar spacers are arranged in one direction at the pixel portion 2 and the edge. The portion 3 is the same as the value of the mountain. In other respects, the cross-sectional area of the columnar spacer 14 is such that the pixel portion has a different value to form the columnar spacer 14. In other words, the cross-sectional area of the pixel portion 2 枉 枉-shaped spacer 14 is & and when the surface of the columnar spacer Μ of the edge portion 3 is S2, the & ratio & is a small value. Hereinafter, the edge portion spacers 14 and the columnar spacers 14 of the pixel portion 2 are set to be differently configured:

O:\85\85611.DOC -11 - 1251106 Reason for the product. Since the shape of the black matrix layer 12 on the bottom surface is poor, the thickness of the cover layer 13 of the edge portion 3 is thicker than that of the pixel portion 2. Further, the columnar spacer 14 forms the height of the rear columnar spacer 14, and since the pixel portion 2 and the edge portion 3 are both at the same height hi, the upper portion of the columnar spacer 14 of the pixel portion 2 and the edge portion 3 is covered. The difference in film thickness of layer 13 is different. Therefore, in the state before the bonding of the substrate, the thickness of the coating layer 13 of the coating layer 13 has a value of κ, and the position of the columnar spacer 14 of the edge portion 3 and the upper portion of the columnar spacer 14 of the pixel portion 2 also has a value of κ. difference. However, the columnar spacer 14 is pressed by the opposing substrate u and the array substrate 16 <the pressurization direction is pressed, and the compression range varies depending on the sectional area of the columnar spacer μ. Specifically, the smaller the sectional area when the pressure is equal, the larger the compression range of the column spacer. In the bonding step of the counter substrate u and the array substrate, the pressure applied to the substrate is substantially constant for the pixel portion 2 and the edge portion 3. In the first embodiment, the columnar spacer 14 per unit area of the pixel portion 2 and the edge portion 3 is fixed. The arrangement intervals are equal, so that the pressure applied to one of the columnar spacers 14 is considered to be equal. As in the first example of the above <liquid crystal display device, the cross-sectional area of the spacer 14 is S1, the edge portion of the pixel portion 2 3 is the compression range of the column spacer 14 when the bonding step is the thickness of the edge portion... The deformation of the array substrate 16 is: 2 due to the coating of the film, you can get the I, / and the moon The compensation function is to homogenize the cell gap of all the pixels of the pixel 2. Specifically, as shown in Fig. 2(b), the sectional area of the column spacers of the edge portion 3 is::: hard The bonding step of the crystal display device array substrate 16 is such that the cross-sectional area s:= is opposite to the substrate 11 and the thickness of the substrate is 1 pixel

O:\85\85611.DOC 1251106 Column spacer of section 2] Upper <flattening amount (hrh2) plus the cover layer 13 of the pixel part 2 盥 络 邵 邵 3, /, side, 袭月吴; poor ha. The cross-sectional area is such that the opposite substrate 阵列 array substrate 16 is affixed to the high-pitched sound of the columnar spacer 14 of the stupid pixel 2 and the stupid pixel. And the columnar spacing of the edge green 3... Height 2 3 2) (4) The central area of the pixel part 2 and the edge of the edge area are both Λ n You ★ Jianjie The cell gap. 4D1 can be uniformly implemented along the pixel portion 2: 2. Since the boundary region between the pixel 2 and the edge portion 3 and the pixel portion 2 are different from each other, the cell gap can be kept.卩 消除 卩 卩 卩 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶 液晶The cell gap of the pixel portion 2 is branched, and the sectional area is controlled so that the dendritic spacer 14 is formed in a single lithography step. Therefore, the problem can be solved. The formation of the column spacer 14 is increased by the increase in the cost of production and the decrease in productivity, so that the occurrence of unevenness in brightness at the time of suppressing the temperature can be suppressed, and in addition, the glass deformation occurs at the south temperature of the edge portion 3, Can improve the picture quality. Second Embodiment Next, a liquid crystal display device of a second embodiment will be described. The second embodiment of the liquid crystal display device has a structure for controlling the uniformity of the cell gap between the arrangement of the column spacers. Hereinafter, it will be specifically described with reference to FIG. 3. Figure 3 (4) corresponds to the area of the 图 line of Figure 1, covering the opposite substrate 2

The upper black matrix layer 22, the cover 厣μ μ p L complex I layer 23 is formed on the column spacer 24

O:\85\85611.DOC -13 - 1251106 is a state before the array substrate 26 is bonded. Further, Fig. 3(b) is a cross-sectional view taken along line VIII of the figure i of the opposite substrate 2i and the array substrate 26, which is vacuum-injected into the liquid crystal. As shown in FIG. 3(b), in the liquid crystal display device of the second embodiment, the black matrix layer 22, the cover layer 23, and the columnar spacers 24 are sequentially formed on the opposite substrate 21, and the columnar spacers 24 are used. Array substrate 26 having a certain cell gap arrangement The columnar spacers 24 are formed by applying a photosensitive resin such as an acrylic resin in a lithography step. Therefore, as shown in Fig. 3 (4), the height of the columnar spacers 24 from the pixel portion 2 and the cover layer 23 of the edge portion 3 are both &amp; Further, as shown in FIG. 3(a), in the liquid crystal display device of the second embodiment, the cross-sectional areas of the columnar spacers 24 of the pixel portion 2 t and the columnar spacers 24 of the edge portion 3 are all, and, in terms of 3 pixels. The portion 2 and the edge portion 3 have their columnar spacers 24 arranged at different I arrangement intervals. That is, when the distance between the columnar spacers 24 of the pixel portion 2 is seven, and the distance between the columnar spacers 24 of the edge portion 3 is the center of the heart, the column spacers 24 are formed so that ds is larger than ten. In other words, the edge portion 3 <the columnar spacer 24 is arranged wider than the columnar spacer 24 of the pixel portion 2. Hereinafter, the reason why the columnar spacers 24 of the edge portions 3 are compared with the columnar members 24 of the pixel portions will be described. The difference between the shape of the bottom surface of the watch and the columnar spacer 24 of the edge portion 3 is compared with the upper position of the second columnar spacer 24 of the pixel portion 2, so that the film thickness of the cover layer 23 is a difference in position above the hb value. Here, in the bonding step of the counter substrate 21 and the array substrate 26, the pressure applied to the columnar spacers 24 is shifted by the pixel portion 1 and the 彖#3 is substantially constant. Therefore, the columnar spacers 24 due to the edge portions 3 are formed. It

O:\85\85611.DOC -14- 1251106 The arrangement interval is wider than that of the pixel portion 2, and the ink force applied to each of the columnar spacers at the edge portion 3 is larger than the columnar spacer applied to the pixel portion 2 Μ The pressure. Also in the laminating step, the greater the pressure applied to each of the columnar spacers ’ the greater the compression amplitude in the height direction of the columnar spacers 24. Therefore, since the arrangement interval of the columnar spacers 24 of the edge portion 3 is made wider, the compression width of the columnar spacers 24 of the edge portion 3 is larger than the compression width of the columnar spacers 24 of the pixel portion 2. Therefore, the deformation of the array substrate 26 due to the film thickness difference hb of the overcoat layer 23 can be compensated for. Since the compensation function can be uniformized along the cell gap of all the pixels 2 . Specifically, in the liquid crystal display device according to the second embodiment, the step of bonding the counter substrate η and the array substrate 26 causes the columnar spacer 24 of the pixel portion 2 to be pressed (h4_h5) to be added to the pixel portion 2 and The thickness difference hb of the cover layer η of the edge portion 3 is the pressure at which the columnar spacer 24 is flattened, and is applied to each of the columnar spacers 24 to the columnar spacer of the mosquito edge portion 3. The height of the columnar spacers 24 of the pixel portion 2 in which the substrate 21 is bonded to the array substrate 26 is "h5". The height of the columnar spacers μ of the edge portion 3 becomes h6, and different heights are formed. Since the arrangement of the columnar spacers 24 is set to be wider than that of the pixel portion 2, the central region of the symplectic portion 2 and the margin portion 3 of the edge portion 3 are bonded to each other. The cell gap in the boundary region between the portion 2 and the edge portion 3 does not occur in the sound. Therefore, the uniformity of the cell gap can be eliminated, and the unevenness of the pixel portion 2 can be eliminated, even in the case of the single-pass, Wenwan, The early color screen prevents the image quality from deteriorating. Another === into the column spacer 24', which prevents the manufacturing cost from increasing. Production and reduced 'configuration and because of the columnar spacer 24 is disposed on an edge portion of 3

O:\85\85611.DOC -15- 1251106 structure, it can also suppress the occurrence of uneven brightness at high temperatures. Further, in the first embodiment and the second embodiment, a liquid crystal display device for black-and-white display will be described, but it is also applicable to a liquid crystal display device capable of displaying color. Further, the liquid crystal display device according to the first embodiment and the second embodiment will be described by a method of forming a columnar spacer on the cover layer on the opposite substrate, but the columnar spacer may be formed on the array substrate. In addition, since there is also a method of performing the substrate processing step not only before the liquid crystal is injected but also after the implantation, it is necessary to adjust the columnar portion of the edge portion of the liquid crystal display device of the first embodiment due to the degree of pressure of the pressing step. The sectional area of the spacer, and the columnar spacer arrangement of the edge portion of the liquid crystal display device of the second embodiment. Further, in the first embodiment, the direction in which one of the columnar spacers of the pixel portion and the edge portion is kept constant is described. In the second embodiment, the cross-sectional area of the pixel portion and the edge portion is constant, but is not limited thereto. In the above aspect, the sectional area and the arrangement interval of the columnar spacers which are set to the edges are applicable to an image display device capable of maintaining unit gap uniformity. Advantageous Effects of Invention As described above, according to the image display device of the present invention, an image display 7F device can be provided at a lower cost by controlling the sectional area and arrangement interval of the columnar spacers at the edge portion, which uniformly maintains the cell gap. , the person with high reliability. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a plan view showing a liquid crystal display device of a first embodiment and a second embodiment. 2(a) to 2(b) are sectional views, taken along line A_A of the liquid crystal display device of Fig. 1, and a liquid crystal display device of the first embodiment. Figure 3 (a) to 3 (b) is a cross section of the liquid crystal display device A_A line O:\85\85611.DOC -16-

Claims (1)

!2511〇6 Picking up, applying for a patent garden: h An image display device having a columnar spacer for holding a certain cell gap on any of the two substrates, characterized in that it is attached Before the two substrates, a columnar spacer is formed, which is different from the sectional area or/and the arrangement interval of the columnar spacers at the edge portion, and is different from the sectional area or/and the arrangement interval of the column spacers of the pixel portion. The value is such that the cell gap between the central portion of the pixel portion and the end portion of the pixel portion after bonding is made uniform. 2. If you apply for a patent range! The image display device of the present invention, wherein the columnar spacer of the edge portion and the columnar spacer of the pixel are the same height before bonding the two substrates. 3. The image display device of claim 2, wherein the cross-sectional area of the columnar spacer of the edge portion is smaller than the cross-sectional area of the columnar spacer of the pixel portion before the two substrates are bonded to each other. small. The image display device according to claim 1 or 2, wherein the columnar spacer of the edge portion is disposed wider than the columnar spacer of the pixel portion before the two substrates are bonded. The image display device according to claim 1 or 2, wherein the beak-shaped spacer is formed of a photosensitive material, and the columnar spacer of the edge portion and the columnar spacer of the pixel portion are identical The lithography step is formed. An image display device according to claim 1 or 2, wherein a liquid crystal layer is formed between the two substrates. O:\85\85611.DOC