JP2009229667A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress occurrence of display unevenness due to a position shift between two substrates during curving. <P>SOLUTION: In the liquid crystal display device comprising: an array substrate having a plurality of rectangular pixel structures disposed in a matrix form; an opposite substrate 101 having a color filter 27 and a black matrix 26; and a liquid crystal layer 102 sandwiched between both the substrates 100 and 101, and having a curved display surface, a plurality of first signal lines 14 in a curving direction and a plurality of second signal lines 12 and 13 orthogonal to the first signal lines 14 are arranged, and a column spacer 23 is formed covering the second signal lines 12 including TFT elements, and not formed at intersections of the first signal lines 14 and second signal lines 12. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device having a curved display surface.

  In general, a transmissive liquid crystal display device includes a liquid crystal panel in which fluid liquid crystal is sealed between a pair of flat glass substrates, and polarizing plates are disposed on both outer surfaces of the glass substrate, a backlight, Are stacked, and the display surface is a flat surface. On the other hand, a liquid crystal display device having a curved display surface can be realized by using a flexible substrate such as thin glass or plastic film having a thickness of 0.3 mm or less. A liquid crystal display device having a curved display surface can provide an excellent function in terms of practicality in addition to a large degree of freedom in terms of design. For example, the reflection of external light can be effectively suppressed by using a specific curved surface shape (see Patent Document 1).

  When manufacturing a liquid crystal display device using a thin glass substrate, in order to maintain the pattern accuracy of various microstructures formed on the substrate surface, and from the viewpoint of ease of handling such as transportation, thick glass is used until the middle of the manufacturing process. A substrate is used, and after the two substrates are bonded, the thickness is reduced by etching or polishing (see Patent Document 2).

  However, when a flat glass substrate is bonded and then the substrate is thinned and curved, luminance unevenness occurs during image display. This is due to the fact that the relative positions of the pixel structures arranged on both substrates shift in the bending direction because the curvatures of the two substrates change by approximately the thickness of the substrates. Such misalignment occurs not only when a thin glass substrate is used, but also when a plastic film is used for the substrate and is bent after being bonded in a flat plate state.

  On the other hand, a method has been proposed in which a resin wall structure is formed in a liquid crystal layer, and two substrates are bonded with the wall structure to suppress misalignment (see Patent Document 3).

  In addition, a method of forming a pixel structure such as a color filter or a black matrix that is usually formed on the counter substrate on the array substrate side has also been proposed (see Patent Document 4).

  Furthermore, a method of providing a column spacer on a channel of a TFT element using a light-shielding material has been proposed (Patent Document 5).

JP-A-6-3650 JP 2005-128411 A JP 2004-219769 A JP 2007-94102 A Japanese Patent Laid-Open No. 2002-23170

  However, in the method of Patent Document 3, a photocurable resin is mixed into the liquid crystal, and the wall structure and the substrate are bonded by light irradiation, so that an uncured component remains in the liquid crystal as an impurity. For this reason, display defects such as image sticking easily occur.

  In addition, in the method of Patent Document 4, since a manufacturing process such as a color filter or a black matrix, which is normally performed in parallel, is added to the manufacturing process of the array substrate, the time required for manufacturing the entire liquid crystal display device becomes long.

  Furthermore, since the method of Patent Document 5 is not provided in a portion that causes light leakage other than the TFT element, it is not possible to sufficiently suppress light leakage due to positional deviation when bent.

  The present invention has been made to solve the above-described problems, and suppresses the occurrence of display unevenness (light leakage) due to the positional deviation of the two substrates due to the curvature, thereby obtaining a high-quality display image. An object of the present invention is to provide a liquid crystal display device.

  A liquid crystal display device according to the present invention includes an array substrate having a plurality of rectangular pixel structures arranged in a matrix, a counter substrate having a color filter and a black matrix, and a liquid crystal layer sandwiched between the substrates. In a liquid crystal display device having a curved display surface, a plurality of first signal lines and a plurality of second signal lines orthogonal to the first signal lines are arranged in the display area of the array substrate along the bending direction. The column spacer is formed so as to cover the second signal line including the TFT element, and is not formed at a portion where the first signal line and the second signal line intersect.

  The liquid crystal display device according to the present invention includes an array substrate having a plurality of rectangular pixel structures arranged in a matrix, a counter substrate having a color filter and a black matrix, and a liquid crystal layer sandwiched between the substrates. In the liquid crystal display device having a curved display surface, a plurality of first signal lines and a plurality of second signal lines orthogonal to the first signal lines are arranged in the display area of the array substrate along the bending direction. The light-shielding material is formed so as to cover the second signal line including the TFT element, and is not formed at a portion where the first signal line and the second signal line intersect. A column spacer is formed on an upper portion of the material having the above.

  Further, the long side of the pixel structure of the array substrate is arranged along the bending direction, the plurality of first signal lines along the bending direction are signal wirings, and the plurality of second signal lines orthogonal to the first signal line A common wiring is provided, and the plurality of second signal lines are scanning wirings.

  The liquid crystal layer is in a TN (Twisted Nematic) mode with a 6 o'clock viewing angle or a 12 o'clock viewing angle, and the bending direction is a horizontal direction of the display surface.

  According to the present invention, a plurality of first signal lines and a plurality of second signal lines orthogonal to the first signal lines are disposed in the display area of the array substrate along the bending direction. Since it is formed so as to cover the second signal line including the element and is not formed at a portion where the first signal line and the second signal line intersect, display unevenness caused by positional deviation between the two substrates at the time of bending Generation can be suppressed and an image display with high luminance can be performed. That is, with this configuration, it is possible to suppress the occurrence of light leakage around the pixel electrode provided in the pixel structure and obtain a liquid crystal display device with little display unevenness.

  Further, in the liquid crystal display device according to the present invention, a plurality of first signal lines and a plurality of second signal lines orthogonal to the first signal lines are arranged along the bending direction in the display area of the array substrate, The light-shielding material is formed so as to cover the second signal line including the TFT element, and is not formed in a portion where the first signal line and the second signal line intersect with each other. Since the column spacers are formed in the LCD, even in a liquid crystal alignment mode other than the TN mode, it is possible to suppress the occurrence of display unevenness due to the positional deviation of the two substrates during bending and to display images with high brightness. can do. That is, with this configuration, it is possible to suppress the occurrence of light leakage around the pixel electrode provided in the pixel structure and obtain a liquid crystal display device with little display unevenness. In many cases, the light-shielding material cannot form a height necessary for the column spacer. Therefore, a laminated structure was adopted.

  Further, the long side of the pixel structure of the array substrate is arranged along the bending direction, the plurality of first signal lines along the bending direction are signal wirings, and the plurality of second signal lines orthogonal to the first signal line Since the common wiring is provided and the plurality of second signal lines are the scanning wiring, an image display with high luminance can be performed. That is, with this configuration, a decrease in the aperture ratio due to the positional deviation when being curved is less than that in the case where the aperture ratio is orthogonal to the curve direction, the aperture ratio can be increased, and a bright liquid crystal display device can be obtained.

  Further, since the liquid crystal layer is in the TN mode at 6 o'clock viewing angle or 12 o'clock viewing angle and the bending direction is the horizontal direction of the display surface, it is possible to display an image with a small change in luminance when viewed from the front. That is, with this configuration, it is possible to obtain an easy-to-see liquid crystal display device with a small change in luminance when the liquid crystal display device is viewed from the front.

Embodiment 1 FIG.
(Pixel structure)
The pixel structure of the liquid crystal display device of the present invention will be described.

  FIG. 1 is a plan view showing a pixel structure before bending of the liquid crystal display device of the present invention. In the display area of the liquid crystal display device of the present invention, a plurality of horizontally long rectangular pixel structures that are long in the bending direction are arranged in a matrix. FIG. 1 shows three of these pixel structures. Each pixel is combined with red (R), green (G), and blue (B) color filters, and color display is performed with three pixels as one unit. The color filters are arranged in stripes of the same color in the bending direction.

  The pixel structure of the present invention will be described with reference to FIG. 1 and FIG. 2 showing a cross section taken along line C1-C1 ′ of FIG. Each pixel structure includes a scanning wiring 12, a common wiring 13, a signal wiring 14, and a gate electrode (a part of the scanning wiring 12 in the figure serves as a gate electrode) disposed on the surface of the glass substrate 11 serving as the array substrate 100 on the liquid crystal layer side. Source electrode 15, drain electrode 16, semiconductor layer 17 (amorphous silicon film), auxiliary capacitance electrode 18, contact hole 19, pixel electrode 20, first insulating film 21, second insulating film 22, column spacer 23, the alignment film 24, and the black matrix 26, the color filter 27, the overcoat film 28, the counter electrode 29, the alignment film 30, and the array substrate 100 disposed on the liquid crystal layer side surface of the glass substrate 25 serving as the counter substrate 101. A liquid crystal layer 102 sandwiched between the substrates 101, and a polarizing plate 103 disposed on both outer surfaces of the array substrate 100 and the counter substrate 101 And the like 104. The pixel structures on the array substrate 100 side and the counter substrate 101 side are rectangles having the same size in plan view. Of the various wirings and electrodes, the scanning wiring 12, the common wiring 13, the signal wiring 14, the gate electrode (12), the source electrode 15, the drain electrode 16, and the auxiliary capacitance electrode 18 are formed of an opaque metal material such as Al or Mo. The pixel electrode 20 and the counter electrode 29 are formed of a transparent conductive material such as ITO (Indium Tin Oxide).

  A region surrounded by a thick dotted line in FIG. 1 is a black matrix opening 31. The black matrix opening 31 becomes a display area in the pixel. That is, there are the signal wiring 14 extending in the bending direction and the scanning wiring 12 extending in the direction intersecting therewith, and there is a pixel display area between the adjacent signal wirings 14 and between the adjacent scanning wirings 12.

  Further, a portion surrounded by a thick solid line in FIG. 1 is a portion where the column spacer 23 is formed. The column spacer 23 is used to keep the distance between the counter substrate 101 and the array substrate 100 approximately constant. The column spacer 23 covers the scanning wiring 12 except for the vicinity of the portion intersecting with the signal wiring 14. Further, the transistor (source electrode 15, drain electrode 16, semiconductor layer 17) connected to the scanning wiring 12 and the signal wiring 14 is also covered. In the pixel, the length of the region in which the column spacer 23 covers the scanning wiring 12 in the direction of the scanning wiring 12 is larger than the length of the black matrix opening 31 in the same direction. For this reason, even if the opening 31 is displaced to the scanning wiring 12 side during bending, the displaced portion is covered with the column spacer 23, so that a portion that deteriorates the display quality is not displayed.

(Functions / operations of each structure)
The function and operation of each structure arranged in each pixel structure will be described.

  By applying a pulse-shaped selection voltage to the scanning wiring 12, pixels in the same column are selected in the vertical direction. An image signal voltage is applied to the signal wiring 14 during a selection period in which the selection voltage is applied. During the selection period, a TFT (Thin Film Transistor) switching element composed of the gate electrode 12, the source electrode 15, the drain electrode 16, the semiconductor layer 17, the first insulating film 21, and the like is turned on, and the signal wiring 14 An image signal voltage is applied from the source electrode 15 connected to the drain electrode 16 to the pixel electrode 20 connected to the drain electrode 16 and the contact hole 19. In this way, the image signal voltages are applied to the pixel electrodes 20 in the same column all at once.

  Subsequently, a selection voltage is applied to the adjacent scanning wiring 12, and the above operation is repeated. By repeating this operation, each image signal voltage is applied to all the pixel electrodes 20 in the display area. In the pixel in the non-selection period in which the selection voltage is not applied, the TFT switching element is turned off, and the potential of the pixel electrode 20 is maintained (because the resistance between the source electrode 15 and the drain electrode 16 becomes high). In order to reduce the fluctuation of the pixel electrode potential during the non-selection period (holding period), an auxiliary capacitance is formed between the auxiliary capacitance electrode 18 and the pixel electrode 20 connected to the common wiring 13.

  A predetermined voltage is applied to the counter electrode 29 disposed on the entire surface of the counter substrate 101 side on the liquid crystal layer side, and the liquid crystal of the liquid crystal layer 102 sandwiched between the pixel electrode 20 and the counter electrode 29 by the voltage between the pixel electrode 20 and the counter electrode 29. The molecular orientation changes. The birefringence of the liquid crystal layer 102 is adjusted by the voltage between the pixel electrode 20 and the counter electrode 29, and the transmittance is controlled by the combination of the array substrate 100 and the polarizing plates 103 and 104 on both outer surfaces of the counter substrate 101. Is done.

  The transmitted light of each pixel is colored in one of RGB colors by the color filter 27 disposed on the counter substrate 101 side. A transparent overcoat film 28 is disposed on the color filter 27, and the surface of the counter substrate 101 on the liquid crystal layer side is flattened, and at the same time, the diffusion of impurities from the color filter 27 to the liquid crystal layer 102 is blocked.

  Here, in each pixel structure, a voltage corresponding to the image signal is applied between the pixel electrode 20 and the counter electrode 29, but a voltage corresponding to the image signal is applied to a portion where the pixel electrode 20 on the array substrate 100 side is not present. The desired transmittance cannot be obtained. Light is shielded by arranging a column spacer 23 so as to cover the scanning wiring 12 including the TFT element in a portion where the pixel electrode 20 is not provided. (The operation of shading will be described later.) In addition, the column spacer 23 is not formed at the intersection of the scanning wiring 12 and the signal wiring 14, and the liquid crystal can be easily moved when liquid crystal is injected or curved. It is said.

  As described above, the pixel structure of the liquid crystal display device of the present invention has a plurality of signal lines 14 along the bending direction in the display area of the array substrate 100, a plurality of scanning lines 12 orthogonal to the signal lines 14 and a common line 13. The column spacer 23 is formed so as to cover the scanning wiring 12 including the TFT element, and is not formed at a portion where the scanning wiring 12 and the signal wiring 14 intersect.

(Panel configuration)
The panel configuration of the liquid crystal display device of the present invention will be described.

  FIG. 3 is a plan view showing a panel configuration before bending of the liquid crystal display device of the present invention. A plurality of pixel structures shown in FIGS. 1 and 2 are arranged in a matrix in a display area 32 surrounded by a broken line. The array substrate 100 and the counter substrate 101 are bonded to each other by a main seal 33 disposed around the display area 32 so that the pixel structures of both the substrates 100 and 101 overlap. The counter electrode 29 of the counter substrate 101 is electrically connected to the wiring on the array substrate 100 side by a transfer agent (not shown) disposed outside the main seal 33. The main seal 33 on either the left or right side (right side in FIG. 3) is provided with an opening (liquid crystal injection port 34) for injecting liquid crystal, and the outside of the injection port 34 is closed with a sealing agent 35. Yes. The array substrate 100 on the side opposite to the liquid crystal injection port 34 (the left side in FIG. 3) has a portion that protrudes from the end portion of the counter substrate 101, and various wirings routed to the protruding portion are flexible substrates. 36 is connected to the external circuit board 37.

  Alignment films 24 and 30 for controlling the alignment state of the liquid crystal molecules are arranged at the interface between the array substrate 100 and the counter substrate 101 with the liquid crystal layer 102, and the surface of the liquid crystal layer is in the direction indicated by the arrow in the figure. An orientation treatment by a rubbing method is performed. By using a left chiral liquid crystal material as the liquid crystal material, a counterclockwise 90 degree twist alignment from the front (opposite substrate 101 side) to the back (array substrate 100 side) can be obtained. When a voltage is applied to the liquid crystal layer 102 by arranging the optical axes (transmission axis or absorption axis) of the polarizing plates 103 and 104 on the outer surfaces of the substrates 100 and 101 in parallel with the alignment processing direction of the respective substrates. When “dark” is not applied, “bright” light / dark control becomes possible. In the case of the panel configuration shown in FIG. 3, the liquid crystal molecules rise from the upper direction (12 o'clock direction) with respect to the surface of the array substrate 100 when a voltage is applied. In the TN mode with a 12 o'clock viewing angle, a wide viewing angle characteristic is obtained in the left-right direction, and a gradation inversion phenomenon occurs in the upward direction. In addition, since the liquid crystal is not aligned in the liquid crystal layer 102 (or there is no liquid crystal), the column spacer 23 is always in the “dark” state.

  The liquid crystal panel is curved in the horizontal direction, and a backlight (not shown) is disposed on the back surface of the array substrate 100 to obtain a liquid crystal display device having a curved display surface. Whether the display surface is curved to a convex surface or curved to a concave surface, the bending direction and the wide viewing angle direction of the TN mode coincide. When a liquid crystal display device having a curved display surface is viewed from the front, the angle at which the display surface is viewed varies depending on the position of the display surface. However, in the liquid crystal panel configuration of the present invention, a uniform display can be achieved over the entire display area as viewed from the front. realizable. Note that the display surface of the liquid crystal display device of the present invention is curved only in one direction (in this case, the horizontal direction) and not curved in the other direction (in this case, the vertical direction).

  FIG. 3 shows the configuration of the liquid crystal panel in the TN mode with a 12 o'clock viewing angle. In the TN mode with a 6 o'clock viewing angle, the left and right directions have a wide viewing angle, and the same effect can be obtained. When the viewing angle is 6 o'clock, the alignment treatment direction of the alignment film 30 is the opposite direction for both substrates, and the gradation inversion phenomenon occurs in the downward direction.

  As described above, the liquid crystal display device of the present invention is a TN mode with a 6 o'clock viewing angle or a 12 o'clock viewing angle, and the bending direction is a horizontal direction of the display surface of the liquid crystal display device.

(Pixel structure when bent)
A pixel structure when the liquid crystal panel of the liquid crystal display device of the present invention is curved will be described.

  FIG. 4 is a perspective view of a liquid crystal panel whose display surface is curved concavely and a plan view showing pixel structures at three positions in the display area. The liquid crystal panel is schematically shown only with two substrates 100 and 101. The plan view of the pixel structure is the same as in FIG. 1 except for the position of the black matrix opening 31. In the vicinity of the center of the display area, the positional relationship between the array substrate 100 and the counter substrate 101 is maintained as it is before being curved, but the pixel structure of the counter substrate 101 in the foreground is shifted left and right outside. (In the drawing, the opening 31 of the black matrix is shifted to the left and right.) However, in the pixel structure of the present invention, a plurality of signal lines 14 and signal lines 14 are orthogonal to the display area of the array substrate 100 along the bending direction. A plurality of scanning lines 12 and a common line 13 are arranged, and the column spacer 23 is formed so as to cover the scanning line 12 including the TFT element, and is formed at a portion where the scanning line 12 and the signal line 14 intersect. Therefore, light leakage can be suppressed even when the black matrix opening 31 is displaced. Therefore, uniform display can be realized over the entire display area.

(Position misalignment generation mechanism)
A mechanism that causes the positional deviation of the pixel structure of the two substrates 100 and 101 during bending will be described.

  FIG. 5 is a cross-sectional view taken along a plane parallel to the bending direction of the two substrates 100 and 101 during bending. Originally, the entire circumference of the two substrates 100 and 101 excluding the liquid crystal injection port 34 is bonded by the main seal 33, but this figure shows the gap between the two substrates 100 and 101 (panel gap). ), And shows a cross section when the substrate is assumed to move freely in the bending direction. When the surface of the counter substrate 101 is curved so as to have a concave shape with a radius of curvature R, the thickness of the counter substrate 101 is T1, the thickness of the array substrate 100 is T2, and the panel gap is d. The radius of curvature differs by (T1 + T2) / 2 + d between the neutral surface 101C (the central surface in the substrate thickness direction) and the neutral surface 100C of the array substrate 100. The difference in the radius of curvature between the two substrates 100 and 101 is the cause of the positional deviation. The length S of the positional deviation when the length of the display region in the bending direction is L and the display area is evenly shifted on both sides of the bending direction is expressed by the following equation.

  Since the thickness of the substrate is very small compared to the radius of curvature, R >> T1. When the thicknesses of the two substrates 100 and 101 are the same, the thickness of the substrate is represented by T and is expressed by the following equation.

  However, the actual liquid crystal panel is slightly different from the case of FIG. 5 because almost the entire periphery of the display area is firmly bonded by the main seal 33. 6 and 7 are cross-sectional views in the bending direction when an actual liquid crystal panel is bent so that the surface of the counter substrate 101 is concave. 6 and 7 are cross-sections at positions C2-C2 ′ and C3-C3 ′ in FIG. 4, respectively, and schematically show only two substrates 100 and 101 and a pixel structure on the inner surface of each substrate. . In the region near the main seal 33 above the liquid crystal panel in FIG. 6, the positional deviation of the two substrates 100 and 101 is restricted by the adjacent main seal 33 over the entire bending direction. Similarly, even in a region near the main seal 33 below the liquid crystal panel, the positional deviation is restricted. On the other hand, in the vicinity of the center of the liquid crystal panel of FIG. 7, the two substrates 100 and 101 are fixed only at the left and right ends by the main seal 33, so that the two substrates are moved away from the vicinity of the center of the display area. A positional shift caused by a difference in curvature radius between 100 and 101 occurs. Since the two substrates 100 and 101 are fixed at the left and right ends, the positional deviation suddenly decreases near the ends. Since the compressive stress in the substrate is very high at the end portion of the inner counter substrate 101, the stress in the substrate is relieved by decreasing the curvature of the end portion or by curving in the opposite direction. (In FIG. 7, the state of the end portion is exaggerated.) Although the shape of the end portion is different from the original curvature, it is difficult to control the shape of the end portion as described later.

  In an actual liquid crystal panel, a positional shift due to the difference in the radius of curvature of the two substrates 100 and 101 occurs in the left and right regions in the bending direction shown in FIG. Although the positional shift amount changes depending on the mechanical properties of the substrate such as Young's modulus and the environmental temperature, the maximum value is the length represented by the formula (1) or the formula (2).

(Black matrix opening)
The shape of the black matrix opening 31 for preventing display unevenness due to the positional shift will be described based on the positional shift generation mechanism.

  The display unevenness due to the positional deviation is due to the black matrix opening 31 protruding outside the pixel electrode 20. A desired voltage is not applied to the liquid crystal layer 102 outside the pixel electrode 20. In the normally white TN mode, which is “dark” when a voltage is applied and “bright” when no voltage is applied, a transparent portion outside the pixel electrode 20 leaks light during dark display. FIG. 8 is a plan view of the pixel structure of the array substrate 100. In the figure, a region surrounded by a thick line is a portion where light leakage occurs. Even in the normally black liquid crystal display mode in which dark display is performed when no voltage is applied, light leakage occurs depending on the voltage applied to the scanning wiring 12 and the signal wiring 14, although not as much as the normally white TN mode. . One side on the right side of the upper, lower, left, and right sides of the pixel electrode 20 is arranged slightly overlapping (about several microns) with the scanning wiring 12 of the adjacent pixel, so that no light leakage occurs. Therefore, when the black matrix opening 31 is shifted to the right side, light leakage does not occur, but a part of the opening 31 is shielded by the scanning wiring 12, so that the transmittance is reduced accordingly. The left side of the pixel electrode 20 is not disposed so as to overlap the scanning line 12 of itself. This is to prevent the pixel electrode potential from greatly changing due to the voltage applied to the scanning wiring 12. (Generally, the change in the pixel electrode potential due to the capacitance with its own scanning wiring 12 is called a feedthrough voltage or kickback voltage.) Also, the upper and lower sides of the pixel electrode 20 are not arranged to overlap the signal wiring 14. This is to suppress the influence (generally referred to as a crosstalk phenomenon) on the pixel electrode potential of the same row to which the image signal voltage is applied from the signal wiring 14 when they are arranged in an overlapping manner.

  Since the long side of the pixel structure of the present invention is arranged along the curved direction, the black matrix opening 31 is displaced in the left-right direction in FIG. Since the column spacer 23 is disposed in the pixel boundary region, the occurrence of light leakage can be suppressed.

(Suppression of decrease in opening area)
In the present invention, the long side of the pixel structure is arranged along the curve direction in order to minimize the decrease in the opening area. When the short side of the pixel structure is arranged along the curve direction, the column spacer 23 is arranged in the pixel boundary region of the long side of the pixel structure of the array substrate 100, and the light blocking ratio is increased by the column spacer 23, thereby opening the aperture. The rate drops significantly.

  In order to minimize the decrease in transmittance, in the present invention, the signal wiring 14 is further arranged along the bending direction, and the scanning wiring 12 and the common wiring 13 are arranged in a direction orthogonal thereto. Conversely, when the scanning wiring 12 and the common wiring 13 are arranged along the curved direction, two wirings are arranged in the long side direction of the pixel structure, and the area ratio occupied by the opaque wiring with respect to the pixel increases. To do.

(Size of liquid crystal display device)
In the first embodiment, the size of the pixel structure is 330 μm wide × 110 μm long, and 640 pixels are arranged in the horizontal direction and 360 × 3 pixels are arranged in the vertical direction. The size of the display area is 211 mm wide × 119 mm long (equivalent to 9.5 inches diagonal). The glass substrate was 0.15 mm thick for both the counter substrate 101 and the array substrate 100. The panel gap was 4.5 μm. The surface of the counter substrate 101 was a concave surface and curved in a substantially arc shape with a radius of curvature of 500 mm. In this case, the maximum value S of the positional deviation between the two substrates 100 and 101 is slightly less than 33 μm from Equation (2).

(Production method)
A method for manufacturing the liquid crystal display device of the present invention will be described.

  In this embodiment, an array substrate and a counter substrate having a predetermined pixel structure are manufactured using two flat glass substrates having a thickness of 0.5 mm, and both substrates are bonded to each other with a thickness of 0.2 mm. The thickness was reduced to 15 mm.

  FIG. 9 is a view showing a cross section of two glass substrates before being bonded together. FIG. 9A shows the counter substrate 101, and FIG. 9B shows the array substrate 100. In this embodiment, four liquid crystal display devices are manufactured using a pair of glass substrates 100 and 101. On the surface of the counter substrate 101, a black matrix 26 having a predetermined shape, a color filter 27, an overcoat film 28, and a counter electrode 29 (all not shown) are stacked in this order. An alignment film 30 is formed on the counter electrode 29, and an alignment process is performed in a predetermined direction. As the alignment film 30, a polymer material such as polyimide is used, and an alignment process is performed by a rubbing method in which the surface of the alignment film 30 is rubbed with a rayon cloth or the like. On the surface of the array substrate 100, various wirings, electrodes, and the like (none are shown) are formed, and pixels are arranged in a matrix. A column spacer 23 made of a photosensitive resin mainly composed of acrylic resin is applied to the uppermost portion of the pixel electrode 20 with a film thickness of 4.8 μm, and a broken line shape is formed in the boundary region in the short side direction of the pixel by the existing exposure / development technology. To do. Thereafter, baking was performed at 230 ° C. for 60 minutes to form a column spacer 23 having a thickness of 4.5 μm (the formation process is not shown). An alignment film 24 is formed thereon, and an alignment process is performed in a predetermined direction. The material of the alignment film 24, the alignment processing method, and the like are the same as those of the counter substrate 101. After the alignment process, a main seal 33 is applied so as to surround a display area composed of a plurality of pixels arranged in a matrix. Further, a dummy seal 38 is also applied to the inside of the outermost periphery of the two glass substrates 100 and 101. A thermosetting resin such as an epoxy resin is used for the main seal 33 and the dummy seal 38.

  Next, the two glass substrates 100 and 101 are bonded together so that the surfaces of the alignment films 24 and 30 face each other, and are thermocompression bonded to harden the main seal 33 and the dummy seal 38. FIG. 10 is a view showing a cross section of the bonded state, and FIG. 11 is a plan view showing shapes of the main seal 33 and the dummy seal 38 on the glass substrate. The main seal 33 applied so as to surround the display area is provided with a liquid crystal injection port 34 which is an opening for liquid crystal injection.

  Next, the two bonded glass substrates 100 and 101 are etched to be thinned by immersing them in an etching solution of hydrofluoric acid (HF) or buffered hydrofluoric acid (BHF: HF + NH4F). . By adjusting the concentration of the etching solution and the immersion time, the thickness of each glass substrate 100, 101 is reduced to around 0.15 mm. The thickness of the glass substrates 100 and 101 is desirably in the range of 0.05 mm to 0.3 mm. If it is too thin, it will be easy to break in the manufacturing process after thinning the glass substrate, for example, a manufacturing process such as liquid crystal injection or polarizing plate attachment, which will be described later.

  After the glass substrates 100 and 101 are thinned, they are cut at a cutting position 39 using a glass scriber or the like and processed into a size equivalent to one liquid crystal display device. Note that the counter substrate 101 is cut inside the array substrate 100 on which the connection terminals are formed on the side where there is a wiring terminal connected to the external image signal output unit.

  Next, after putting the cut and bonded glass substrates 100 and 101 and the liquid crystal in a vacuum container to make a vacuum, the liquid crystal injection port 34 is brought into contact with the liquid crystal. By returning the vacuum vessel to atmospheric pressure, liquid crystal is injected from the injection port. At this time, since the column spacer 23 has a broken line shape, a liquid crystal can be injected smoothly by securing a path through which the liquid crystal is injected. FIG. 12 shows a cross section in a state where the liquid crystal is injected. As the liquid crystal, a left chiral nematic liquid crystal having a positive dielectric anisotropy is used. The birefringence of the liquid crystal is 0.085 to 0.090 (value at a wavelength of 589 nm). After the liquid crystal is injected, the injection port 34 is closed with a sealing agent. An ultraviolet curable adhesive is used as the sealing agent.

  Next, as shown in FIG. 13, polarizing plates 103 and 104 are attached to both outer surfaces of the counter substrate 101 and the array substrate 100. The polarizing plates 103 and 104 are made of a stretched PVA (polyvinyl alcohol) dyed with iodine and sandwiched between two TAC (cellulose triacetate) films. A film-like adhesive is used for attaching the polarizing plates 103 and 104. FIG. 13 shows a cross section in a state where the polarizing plates 103 and 104 are attached. After the polarizing plates 103 and 104 are attached, the wiring on the array substrate 100 and an external circuit board are connected by a flexible substrate 36 (both not shown). As described above, the liquid crystal panel portion of the liquid crystal display device was manufactured.

  Next, as shown in FIG. 14, the liquid crystal panel and the support plate 105 were attached using a sheet-like adhesive film while pressing the liquid crystal panel against the support plate 105 with the roller 40. The support plate 105 is made of a transparent resin such as acrylic or polycarbonate that is shaped into a curved shape with a predetermined curvature (a curvature radius obtained by adding the thickness of the liquid crystal panel to the curvature radius of a desired display surface). However, at the end in the bending direction of the liquid crystal panel, as described above, the stress in the inner counter substrate 101 was too strong to obtain a predetermined curvature, and the support plate 105 was slightly deformed.

  A curved liquid crystal panel and a support plate 105 were stacked on the backlight 106, and the casing 107 was covered from the opposite substrate 101 side, and connected to the circuit substrate 37 by the flexible substrate 36 to manufacture a liquid crystal display device. FIG. 15 is a horizontal sectional view of the liquid crystal display device, and FIG. 16 is a perspective view. The backlight 106 has a laminated structure of backlights of a normal liquid crystal display device, and includes a reflection sheet, a light guide plate, a diffusion sheet, a lamp, and the like (all not shown). A transparent protective plate 108 is disposed on a portion of the housing 107 that contacts the display surface.

Embodiment 2. FIG.
In the first embodiment, the liquid crystal display device in which the display surface is curved concavely has been described. In Embodiment 2, a liquid crystal display device whose display surface is curved to a convex surface will be described.

  The pixel structure and the liquid crystal panel configuration before bending are the same as those in the first embodiment. FIG. 17 is a perspective view of a liquid crystal panel having a convex display surface and a plan view showing pixel structures at three positions in the display area. The liquid crystal panel is schematically shown only with two substrates 100 and 101. Similar to the case where the surface is curved to the concave surface, the positional relationship between the array substrate 100 and the counter substrate 101 is maintained as it was when the plate was curved before the center of the display area. On the other hand, on the left and right of the display area, the pixel structure of the counter substrate 101 in front is shifted to the left and right inside. However, the pixel structure of the present invention has a plurality of signal lines 14 in the display area of the array substrate 100 and a plurality of signal lines 14 orthogonal to the signal lines 14 along the curve direction. The scanning wiring 12 and the common wiring 13 are arranged, and the column spacer 23 is formed so as to cover the scanning wiring 12 including the TFT element, and is not formed at a portion where the scanning wiring 12 and the signal wiring 14 intersect. The occurrence of light leakage can be suppressed. Accordingly, uniform display can be realized over the entire display area, as in the case of being curved concavely.

  Note that, as shown in FIG. 18, the maximum value of the positional deviation when the display surface is curved into a convex surface is defined by the outermost surface, so that the mathematical formula (3) slightly different from the mathematical formula (1). It is represented by

  However, since the thicknesses T1 and T2 of the counter substrate 101 and the array substrate 100, and the panel gap d are much smaller than the radius of curvature R, the maximum value of the positional deviation is expressed by Equation (2) as in the case where the concave surface is curved. Is done.

Embodiment 3 FIG.
In Embodiment 3, the case where the display surface is curved in the vertical direction when the liquid crystal display device is viewed from the front will be described.

  Since the bending direction is the vertical direction, the pixel structure is a rectangle that is long in the vertical direction. FIG. 19 is a plan view of the pixel structure in the third embodiment. The size of the pixel structure was 110 μm wide × 330 μm long, and the length of the pixel electrode in the bending direction was 310 μm as in the first and second embodiments. 360 × 3 pixels are arranged in the horizontal direction and 640 pixels are arranged in the vertical direction. The size of the display area is 119 mm wide × 211 mm long (equivalent to 9.5 inches diagonal). The glass substrate is 0.15 mm thick for both the counter substrate 101 and the array substrate 100, and the panel gap is 4.5 μm. The surface of the counter substrate 101 is a convex surface, and is curved in a substantially arc shape with a curvature radius of 500 mm. In this case, the maximum value of the positional deviation between the two substrates is a little less than 33 μm from Equation (2).

  FIG. 20 is a plan view showing a panel configuration of the liquid crystal display device before bending. Similar to the first and second embodiments, the TN mode with a 12 o'clock viewing angle is adopted.

  FIG. 21 is a perspective view of a liquid crystal panel having a convex display surface and a plan view showing pixel structures at three positions in the display area. The liquid crystal panel is schematically shown only with two substrates 100 and 101. In the vicinity of the center of the display area, the positional relationship between the array substrate 100 and the counter substrate 101 is maintained as it is before flattening. On the other hand, the pixel structure of the front counter substrate 101 is shifted inward in the vertical direction above and below the display area. However, in the pixel structure of the present invention, a plurality of signal wirings 14, a plurality of scanning wirings 12 orthogonal to the signal wirings 14, and a common wiring 13 are arranged in the display region of the array substrate 100 along the bending direction. 23 is formed so as to cover the scanning wiring 12 including the TFT element, and is not formed at a portion where the scanning wiring 12 and the signal wiring 14 intersect with each other, so that occurrence of light leakage can be suppressed. Accordingly, uniform display can be realized over the entire display area, as in the case of being curved concavely.

  However, when the liquid crystal display device of the present embodiment is viewed from the front, the lower portion of the display area is viewed from slightly above the liquid crystal panel surface. Since this direction is the tone reversal direction of the TN mode with a 12 o'clock viewing angle, the brightness at the time of bright display is slightly darker and the brightness at the time of dark display is slightly brighter than the center or upper part of the display area.

  In the embodiment of the present invention, the photosensitive resin mainly composed of acrylic resin is used for the column spacer 23, and the example has the transparency. However, since the light shielding is caused by the absence of the alignment of the liquid crystal, it functions. There is no problem above. Further, a resin in which a black pigment is mixed into the column spacer 23 or another dye is mixed may be used.

Embodiment 4 FIG.
A pixel structure of the liquid crystal display device according to the fourth embodiment of the present invention will be described.

  FIG. 22 is a plan view showing a pixel structure before bending of the liquid crystal display device of the present invention. In the display area of the liquid crystal display device of the present invention, a plurality of horizontally long rectangular pixel structures that are long in the bending direction are arranged in a matrix. FIG. 22 shows three of these pixel structures. Each pixel is combined with a color filter of red (R), green (G), and blue (B), and color display is performed with three pixels as one unit. The color filters are arranged in stripes of the same color in the bending direction.

  Description will be made with reference to FIG. 22 and FIG. 23 showing a cross section taken along line C4-C4 'of FIG. Components having the same functions as those in Embodiment 1 are denoted by the same reference numerals. In the fourth embodiment, in the display area of the array substrate 100, a plurality of signal wirings 14 and a plurality of scanning wirings 12 and a common wiring 13 orthogonal to the signal wirings 14 are arranged along the bending direction, thereby shielding light. And the black matrix 26 is formed so as to cover the scanning wiring 12 including the TFT element, and is not formed at the portion where the signal wiring 14 and the scanning wiring 12 intersect. The column spacer 23 is formed above the black matrix 26. Is formed. In the case of Embodiment 4 of the present invention, since the black matrix 26 has a light blocking function, it is not necessary to block light by the column spacer 23. Further, in order to secure the injection path for the liquid crystal injection, it is better to make the black matrix 26 in a broken line shape.

  However, a process for forming both the black matrix 26 and the column spacer 23 is required, and the time required for manufacturing the entire liquid crystal display device becomes long.

  In the fourth embodiment of the present invention, when the liquid crystal display device is curved as in the first to third embodiments, the black matrix 26 is disposed even if the array substrate 100 and the counter substrate 101 are misaligned. Therefore, the occurrence of light leakage can be suppressed.

  In the fourth embodiment of the present invention, as described above, the black matrix 26 is provided with a light shielding function, so that a liquid crystal alignment mode other than the TN mode, for example, a VA (Vertical Alignment) mode, an IPS (In-Plane Switching) mode. ) Mode, the same effect can be obtained.

(For various curved shapes)
The above embodiment is a case where the entire display surface of the liquid crystal display device is curved with the same curvature in a specific direction. Even when the display surface is partially curved, the display surface is curved with different curvatures, or the display surface is curved unevenly, the shape of the black matrix opening that takes into account the maximum amount of positional displacement can be achieved. The light leakage suppression effect is obtained.

  In FIG. 24, a part of the display surface (length L1) is curved in a concave shape with a radius of curvature R1, and the remaining (length L2) is a plane parallel to the bending direction of the two substrates 100 and 101 in the case of a flat plate. FIG. Similarly to FIG. 5, the main seal 33 serves to maintain the panel gap, and the cross section when the substrates 100 and 101 are assumed to move freely in the bending direction is shown. Assuming that the two substrates 100 and 101 are fixed at the right end of the flat plate portion, the length S1 of the positional deviation at the left end of the display surface is expressed by a formula where the thickness of the substrates 100 and 101 is T and the panel gap is d. It is represented by (4).

  Therefore, the length of the opening of the black matrix 26 in the bending direction may be shorter than the pixel electrode length by S1 or more.

  FIG. 25 shows the two substrates 100 and 101 when a part of the display surface (length L1) is curved in a concave shape with a radius of curvature R1, and the remaining (length L2) is curved in the same direction with a radius of curvature R2. It is sectional drawing in a surface parallel to a bending direction. Similarly to FIG. 24, the main seal 33 serves to maintain the panel gap, and the cross section is shown assuming that the substrates 100 and 101 move freely in the bending direction. Assuming that the two substrates 100 and 101 are fixed at a position where the radius of curvature changes, the length S1 of the positional deviation at the left end of the display surface is expressed by Equation (4), and the positional deviation at the right end of the display surface is expressed. The length is expressed by Equation (5).

  Therefore, the length of the opening of the black matrix 26 in the bending direction may be shorter than the pixel electrode length by S1 + S2 or more.

  When the curvature is asymmetrical on the left and right sides of the display surface (including the case where one is a flat plate) as in the above two cases, the positional deviation does not occur evenly on the left and right sides of the display surface. It changes depending on R1, R2, L1, L2) in FIGS.

  Even in such a case, light leakage can be suppressed because the left and right light shielding regions are formed by the column spacers 23.

  In FIG. 26, half of the display surface (length L1) is concavely curved with a radius of curvature R1, and the other half of the two substrates 100 and 101 is curved in the opposite direction, that is, convexly with the same curvature. It is sectional drawing in a surface parallel to a bending direction. As in FIG. 25, the main seal 33 serves to maintain the panel gap, and the cross-section when the substrates 100 and 101 are assumed to move freely in the bending direction is shown. Assuming that the two substrates 100 and 101 are fixed at a position where the bending direction changes, the length S1 of the positional deviation at both ends of the display surface is expressed by Equation (4).

  When the bending directions on the left and right sides of the display surface are opposite, the misalignment directions match. In the case of FIG. 26, since the left and right ends of the display areas of the two substrates 100 and 101 are fixed by the main seal 33 in the actual liquid crystal panel, the pixel structure on the counter substrate 101 side is shifted to the right, and the amount of displacement The maximum value of is S1.

  In FIG. 27, a part of the display surface (length L1) is curved in a concave shape with a radius of curvature R1, and the remaining (length L2) is curved in a convex shape with a radius of curvature R2. It is sectional drawing in a surface parallel to a bending direction. Similarly to FIG. 26, the main seal 33 serves to maintain the panel gap, and the cross section when the substrates 100 and 101 are assumed to move freely in the bending direction is shown. Assuming that the two substrates 100 and 101 are fixed at a position where the bending direction changes, the length S1 of the positional deviation at the left end of the display surface is expressed by Equation (4), and the length of the positional deviation at the right end. S2 is expressed by Equation (5).

  Also in this case, the direction of the positional deviation coincides, and the maximum value of the positional deviation amount is the larger value of S1 and S2.

  When the bending direction is reversed on the left and right of the display surface as in the above two cases, the positional deviation occurs in either the left or right direction of the display surface, but the light shielding region is formed by the column spacers 23 on both the left and right sides. Therefore, light leakage can be suppressed.

  In the embodiment of the present invention, the pixel structure of the array substrate 100 has a long side arranged along the bending direction, a plurality of signal wirings 14 along the bending direction, and a plurality of scanning wirings 12 orthogonal to the signal wirings 14. The common wiring 13 was used. Thereby, an aperture ratio can be made high and a bright liquid crystal display device can be obtained.

  On the contrary, when the pixel structure of the array substrate 100 is arranged with the short sides along the bending direction, the plurality of scanning wirings 12 and the common wiring 13 along the bending direction, and the plurality of signal wirings 14 orthogonal to the scanning wiring 12. As shown in FIG. 28, the opening becomes smaller. Further, as shown in FIG. 29, when the lens is bent, the opening is further reduced due to misalignment, and a bright display cannot be obtained. Therefore, the pixel structure of the array substrate 100 is arranged with the long sides along the bending direction. A plurality of signal wirings 14 and a plurality of scanning wirings 12 and a common wiring 13 orthogonal to the signal wirings 14 are preferable.

It is a top view which shows the pixel structure of the liquid crystal display device by Embodiment 1 of this invention. It is sectional drawing which shows the pixel structure of the liquid crystal display device by Embodiment 1 of this invention. It is a top view which shows the liquid crystal panel structure of the liquid crystal display device by Embodiment 1 of this invention. FIG. 2 is a perspective view showing a curved shape of the liquid crystal display device according to Embodiment 1 of the present invention and a plan view showing a pixel structure. It is sectional drawing which shows the position shift which arises when two board | substrates are curved to a concave surface. It is sectional drawing at the time of curving a liquid crystal panel. It is sectional drawing at the time of curving a liquid crystal panel. It is a top view which shows the light leak generation | occurrence | production area | region in a pixel structure. It is sectional drawing which shows the manufacturing process of the liquid crystal display device by Embodiment 1 of this invention. It is sectional drawing which shows the manufacturing process of the liquid crystal display device by Embodiment 1 of this invention. It is a top view which shows the manufacturing process of the liquid crystal display device by Embodiment 1 of this invention. It is sectional drawing which shows the manufacturing process of the liquid crystal display device by Embodiment 1 of this invention. It is sectional drawing which shows the manufacturing process of the liquid crystal display device by Embodiment 1 of this invention. It is sectional drawing which shows the manufacturing process of the liquid crystal display device by Embodiment 1 of this invention. It is sectional drawing which shows the liquid crystal display device by Embodiment 1 of this invention. It is a perspective view which shows the liquid crystal display device by Embodiment 1 of this invention. It is the perspective view which shows the shape at the time of the curvature of the liquid crystal display device by Embodiment 2 of this invention, and a top view which shows a pixel structure. It is sectional drawing which shows the position shift which arises when two board | substrates are curved to a convex surface. It is a top view which shows the pixel structure of the liquid crystal display device by Embodiment 3 of this invention. It is a top view which shows the liquid crystal panel structure of the liquid crystal display device by Embodiment 3 of this invention. It is the perspective view which shows the shape at the time of curvature of the liquid crystal display device by Embodiment 3 of this invention, and a top view which shows a pixel structure. It is a top view which shows the pixel structure of the liquid crystal display device by Embodiment 4 of this invention. It is sectional drawing which shows the pixel structure of the liquid crystal display device by Embodiment 4 of this invention. It is sectional drawing which shows the position shift which arises when a part of display surface is curved to a concave surface. It is sectional drawing which shows the position shift which arises when making it curve to the concave surface of a different curvature on the right and left of a display surface. It is sectional drawing which shows the position shift which arises when making it curve in the reverse direction on the left and right of a display surface. It is sectional drawing which shows the position shift which arises when making it curve with a different direction and a different curvature on the right and left of a display surface. It is a top view which shows the pixel structure of the liquid crystal display device which rotated the bending direction and pixel arrangement | positioning 90 degree | times. It is sectional drawing which shows the pixel structure of the liquid crystal display device which rotated the bending direction and pixel arrangement | positioning 90 degree | times.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 Glass substrate, 12 Scan wiring, 13 Common wiring, 14 Signal wiring, 15 Source electrode, 16 Drain electrode, 17 Semiconductor layer, 18 Auxiliary capacity electrode, 19 Contact hole, 20 Pixel electrode, 21 1st insulating film, 22 1st 2 insulating film, 23 column spacer, 24 alignment film, 25 glass substrate, 26 black matrix, 27 color filter, 28 overcoat film, 29 counter electrode, 30 alignment film, 31 black matrix opening, 32 display area, 33 main Seal, 34 Liquid crystal injection port, 35 Sealant, 36 Flexible substrate, 37 Circuit board, 38 Dummy seal, 39 Cutting position, 40 Roller, 100 Array substrate, 101 Counter substrate, 102 Liquid crystal layer, 103, 104 Polarizing plate, 105 Support Board, 106 Backlight, 107 Case, 108 protective plate, neutral surface of 100C array substrate, neutral surface of 101C counter substrate.

Claims (4)

An array substrate having a plurality of rectangular pixel structures arranged in a matrix;
A counter substrate having a color filter and a black matrix;
A liquid crystal layer sandwiched between the array substrate and the counter substrate;
In a liquid crystal display device having a curved display surface,
In the display area of the array substrate, a plurality of first signal lines along the bending direction, a plurality of second signal lines orthogonal to the first signal lines are arranged,
A column spacer is formed so as to cover the second signal line including the TFT element, and is not formed at a portion where the first signal line and the second signal line intersect. An array substrate having a plurality of rectangular pixel structures arranged in a matrix;
A counter substrate having a color filter and a black matrix;
A liquid crystal layer sandwiched between the array substrate and the counter substrate;
In a liquid crystal display device having a curved display surface,
In the display area of the array substrate, a plurality of first signal lines along the bending direction, a plurality of second signal lines orthogonal to the first signal lines are arranged,
A light-shielding material is formed so as to cover the second signal line including the TFT element, and is not formed at a portion where the first signal line and the second signal line intersect. A liquid crystal display device, wherein a column spacer is formed on an upper portion of a material having the same.   The long sides of the pixel structure of the array substrate are arranged along the bending direction, the plurality of first signal lines along the bending direction are signal wirings, and the plurality of first signals orthogonal to the first signal line The liquid crystal display device according to claim 1, wherein a common wiring is provided for the two signal lines, and the plurality of second signal lines are scanning wirings.   4. The liquid crystal layer according to claim 1, wherein the liquid crystal layer is in a TN (Twisted Nematic) mode with a viewing angle of 6 o'clock or 12 o'clock, and the bending direction is a horizontal direction of the display surface. A liquid crystal display device according to 1.

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