JP2010190997A - Liquid crystal display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal panel wherein the brightness variation due to positional deviation when sticking an array substrate and a counter substrate to each other is suppressed. <P>SOLUTION: On an array substrate 12, a spacer 15 which is brought into contact with a counter substrate 13 to hold a gap between substrates 12 and 13 is projectingly formed. A projecting portion 56 is provided around a regular contact position 59 of the spacer 15 on the counter substrate 13. When substrates 12 and 13 are deviated from regular positions when being stuck to each other, the spacer 15 is placed on the projecting portion 56 to widen a gap d between the substrates 12 and 13, and transmittance of a liquid crystal layer between the substrates 12 and 13 is increased. The reduction of an aperture ratio, which is caused by covering sub-pixels with a black matrix layer 58 due to the positional deviation of substrates 12 and 13 is canceled by the increase of transmittance, whereby the reduction of brightness can be suppressed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a liquid crystal display element in which an array substrate and a counter substrate are bonded to each other.

  Conventionally, a liquid crystal panel which is a liquid crystal display element as this type of liquid crystal display element includes an array substrate, a counter substrate disposed opposite to the array substrate, and a liquid crystal layer which is a light modulation layer interposed between the substrates. I have.

  The array substrate has scanning lines and wirings such as video signal lines as signal lines in a grid pattern on a substrate having insulating properties, and is arranged at a crossing position of these wirings, and pixel electrodes forming each pixel; A display region having a thin film transistor (TFT) as a switching element for driving the pixel electrode is provided. A thin film transistor has a gate electrode connected to a scanning line, a source electrode connected to a video signal line, a drain electrode connected to a pixel electrode, and is turned on / off by a scanning signal from the scanning line. A voltage is written to the pixel electrode.

  Further, the counter substrate is arranged in a position corresponding to each pixel on the array substrate side on the light-transmitting and insulating substrate, and red (R), green (G), and blue (B) which are primary colors constituting white. Each color portion of the color filter is provided with a color filter layer having colored portions such as stripes and a counter electrode which is a common electrode (common electrode) for applying a voltage to the liquid crystal layer between the pixel electrodes. A black matrix layer, which is a light shielding layer, is formed therebetween.

  In this liquid crystal panel, for example, a spacer, which is a gap holding member for holding a gap between the array substrate and the counter substrate, is formed on the counter substrate at a position corresponding to the black matrix layer. It is configured by aligning and bonding by an adhesive portion outside the display area (see, for example, Patent Document 1).

JP 2003-121859 A

  When the array substrate and the counter substrate are bonded to each other, there is generally a deviation in the vertical and horizontal directions (vertical direction and horizontal direction) with respect to the design position, that is, the normal position. However, when such a shift occurs, the positions of the video signal lines and the black matrix layer that overlap each other at the design position shift, so that the black matrix layer covers a part of the pixel electrode and the aperture ratio decreases. It has the problem that it ends up.

  Since the amount of deviation between the array substrate and the counter substrate differs depending on the manufactured liquid crystal panel, the surface luminance differs depending on the liquid crystal panel, resulting in variation in luminance. Variations in characteristics lead to deterioration of the quality of the liquid crystal panel.

  The present invention has been made in view of such a point, and an object of the present invention is to provide a liquid crystal display element in which variation in luminance due to a positional shift at the time of bonding an array substrate and a counter substrate is suppressed.

  The present invention relates to an array substrate having a plurality of pixels arranged in a matrix, switching elements for driving the pixels, and wiring connected to the switching elements, and an array substrate facing the array substrate and bonded together. A counter substrate having a light shielding portion at a position corresponding to at least a part of the wiring, a liquid crystal layer interposed between the array substrate and the counter substrate, and at least one of the array substrate and the counter substrate A gap holding member that protrudes on one side and holds the gap between the array substrate and the counter substrate by contacting the other of the array substrate and the counter substrate; and a member having translucency, Protruding portions provided on the other side of the counter substrate and positioned around the normal contact position of the gap holding member.

  Then, at least one of the array substrate and the counter substrate is provided with a gap holding member that holds the gap between the array substrate and the counter substrate by contacting the other of the array substrate and the counter substrate, and the array substrate A protrusion is provided around the normal contact position of the other gap holding member between the counter substrate and the counter substrate.

  According to the present invention, when the alignment between the array substrate and the counter substrate is displaced with respect to the normal position, the gap holding member overlaps the protrusion and the gap between the array substrate and the counter substrate widens. The transmittance of the liquid crystal layer between the array substrate and the counter substrate increases, and the aperture ratio decreases due to the light shielding portion covering the pixels due to the positional deviation between the array substrate and the counter substrate. By canceling out, it is possible to suppress a decrease in luminance.

1 shows a liquid crystal display element according to an embodiment of the present invention, (a) is a plan view schematically showing a pixel, (b) is a schematic view of a state where an array substrate and a counter substrate are bonded together at a regular position. FIG. 4C is a cross-sectional view schematically showing a state in which the array substrate and the counter substrate are bonded to each other at a position shifted from a normal position. It is a longitudinal cross-sectional view which shows a part of liquid crystal display element same as the above. It is a circuit diagram which shows the array substrate of a liquid crystal display element same as the above. It is a graph which shows the relationship between the transmittance | permeability and retardation of a liquid crystal display element same as the above.

  Hereinafter, the configuration of a liquid crystal display element according to an embodiment of the present invention will be described with reference to FIGS.

  1 to 3, reference numeral 11 denotes a liquid crystal panel which is an active matrix type liquid crystal display element as a display element. In the liquid crystal panel 11, an array substrate 12 which is a substrate and a counter substrate 13 which is a substrate are arranged to face each other. In addition, a liquid crystal layer 14 as a light modulation layer is interposed between the substrates 12 and 13, and a gap (distance) between the substrates 12 and 13, that is, a gap is formed by a gap holding member formed of, for example, a resin. It is held by a plurality of spacers 15. Furthermore, the array substrate 12 and the counter substrate 13 are bonded together by a seal portion (not shown) whose peripheral portion is an adhesive portion. In the liquid crystal panel 11, polarizing plates (not shown) are attached to the array substrate 12 and the counter substrate 13, respectively.

  In the following description, the liquid crystal panel 11 is described as a transmissive type, but it is needless to say that the liquid crystal panel 11 may be a reflective type or a transflective type.

  The array substrate 12 is positioned on the backlight side (not shown), and is a flat substrate (not shown) on the main surface of the glass substrate 21 on the side of the liquid crystal layer 14 of the transparent substrate as the array substrate body having translucency and insulation. A wiring 24 in which scanning lines 22, signal lines 23, and the like are formed in a lattice pattern, and a thin film transistor (TFT) 25 as a switching element are formed in a pattern via an insulating film. The scanning line 22 and the signal line 23 are insulated from each other at an intersecting position by an interlayer insulating film (not shown), and the wiring 24 and the thin film transistor 25 are covered with the insulating film 26. Further, a pixel electrode 27 constituting the sub-pixel P which is a pixel is formed on the insulating film 26, and an alignment film (not shown) is formed so as to cover the pixel electrode 27. The spacers 15 are formed on the array substrate 12 so as to correspond to the intersection positions of the scanning lines 22 and the signal lines 23. In the array substrate 12, a rectangular area where the sub-pixels P are arranged in a matrix is a display area 28.

  Each scanning line 22 is formed in a straight line shape along the horizontal (H) direction by a conductive member such as aluminum or copper, and a part of the scanning line 22 protrudes to become a gate electrode of each thin film transistor 25.

  Each signal line 23 is formed linearly along the vertical (V) direction by a conductive member such as aluminum or copper.

  Each thin film transistor 25 has a gate electrode connected to the scanning line 22, a source electrode connected to the signal line 23, and a drain electrode connected to the pixel electrode 27, from the gate driver 33 which is a scanning line driving circuit. Switching is controlled by applying a signal to the gate electrode via the scanning line 22, and a voltage is applied to the pixel electrode 27 corresponding to the signal input from the source driver 34, which is a signal line driving circuit, via the signal line 23. By applying this, the sub-pixels P are independently turned on / off.

  The pixel electrode 27 is formed between adjacent signal lines 23 and 23 by a transparent conductive material such as ITO (Indium Tin Oxide). That is, the pixel electrode 27 has a width dimension substantially equal to that between the signal lines 23 and 23.

  On the other hand, the counter substrate 13 is located on the display side of the liquid crystal panel 11, and is a transparent substrate as a counter substrate body having translucency and insulation, that is, on the array substrate 12 side on one main surface of the glass substrate 51. The colored portions 52r, 52g, and 52b corresponding to red (R), green (G), and blue (B), which are the primary colors constituting white, are arranged along the vertical (V) direction at positions corresponding to the sub-pixels P. And a color filter layer 52 as a colored layer. Further, the counter electrode 53 and the overcoat layer 54 which are common electrodes (transparent electrodes) are formed so as to cover the color filter layer 52, and an alignment film (not shown) is formed so as to cover the overcoat layer 54, A frame portion (not shown) that is a light shielding portion is formed around the color filter layer 52. Further, protrusions 56 are respectively formed around the positions between the colored portions 52r, 52g, 52b of the color filter layer 52, for example, on both sides in the horizontal (H) direction.

  The color filter layer 52 has a stripe shape in which the colored portions 52r, 52g, and 52b are periodically arranged in the horizontal (H) direction. A black matrix layer 58 serving as a light shielding portion is formed along the vertical (V) direction at a position between the colored portions 52r, 52g, and 52b of the color filter layer 52.

  The black matrix layer 58 is formed on one main surface of the glass substrate 51 with a width dimension equal to or smaller than the width dimension of the signal line 23 by using, for example, a black resin, and the array substrate 12 and the counter substrate 13 are designed positions, that is, When pasted together at regular positions, the signal lines 23 overlap with each other, and the signal lines 23 are arranged so as not to overlap the pixel electrode 27.

  The protrusions 56 are formed in a continuous plan view along, for example, the vertical (V) direction on both sides of the color filter layer 52 between the colored portions 52r, 52g, and 52b by a member such as a resin having translucency. It is formed in a stripe shape, and is formed with a protruding amount of about 1 μm, for example, toward the array substrate 12 side. In addition, each projecting portion 56 has inclined inclined surfaces 56a and 56a that are inclined so as to reduce the width dimension, and a flat surface 56b that has a tip portion continuous to the inclined surfaces 56a and 56a. It has become. That is, each protrusion 56 is formed in a mountain shape whose width dimension decreases toward the tip side. Further, each projection 56 has a projection amount p corresponding to a shift amount Δx of the spacer 15 with respect to the normal contact position 59 with the counter substrate 13 side, and the transmittance T of the liquid crystal layer 14 between the substrates 12 and 13. Is set to change. Specifically, the deviation amount Δx from the normal contact position 59 and the protrusion amount p at that position have a predetermined correspondence (proportional relationship here).

  The regular contact position 59 is a place where the spacer 15 contacts the counter substrate 13 as designed. In the present embodiment, the regular contact position 59 is on the counter substrate 13, but when the spacer 15 is disposed on the counter substrate 13 side, the regular contact position is on the array substrate 12.

  FIG. 4 shows the relationship between the transmittance T of a TN (Twisted Nematic) liquid crystal and the retardation Δn · d. According to FIG. 4, the transmittance T of the liquid crystal layer 14 between the substrates 12 and 13 with respect to the change in the gap d between the substrates 12 and 13 is the difference in refractive index Δn (for example, 0.1) of the liquid crystal layer 14. It changes with the change of retardation Δn · d, which is the product of.

  The counter electrode 53 is for applying a voltage to the liquid crystal layer 14 between the pixel electrode 27 and is formed of a transparent conductive material such as ITO, for example.

  The liquid crystal layer 14 is a light modulation layer formed of a predetermined liquid crystal material, and is interposed between the alignment film on the array substrate 12 side and the alignment film on the counter substrate 13 side. The liquid crystal layer 14 may be formed by a vacuum dropping method, or may be formed by an injection method by forming an injection port communicating with the display region 28 at a predetermined position of the seal portion.

  Further, the spacer 15 is formed in a columnar shape having a height dimension h of, for example, about 4 μm, using, for example, a transparent resin having no conductivity.

  The seal portion is formed by curing an adhesive such as a thermosetting resin or a photocurable resin.

  Next, the manufacturing method of the one embodiment will be described.

  First, a general film forming process and a patterning process are repeated on the glass substrate 21 to form each pattern of the wiring 24, the thin film transistor 25, the pixel electrode 27, and the like to constitute the array substrate 12, and the glass substrate 51 On top of this, the general film forming process and the patterning process are repeated to form the respective patterns such as the color filter layer 52, the counter electrode 53, the overcoat layer 54, etc. The counter substrate 13 is bonded to the counter substrate 13 with a seal portion so that the liquid crystal material constituting the liquid crystal layer 14 is interposed.

  In actual manufacturing, each pattern on the array substrate 12 side is imposed in a matrix on a large glass substrate, which is a mother glass from which the glass substrate 21 is cut, and is arranged in a matrix. On the large glass substrate that is the mother glass that cuts out the substrate 51, each pattern on the counter substrate 13 side is imposed in a matrix form for a plurality of liquid crystal panels 11 minutes, and these large format glass substrates are bonded together by a seal portion. Here, for the sake of convenience, description will be made assuming that the array substrate 12 and the counter substrate 13 are bonded together.

  When the substrates 12 and 13 are bonded together, as shown in FIGS. 1A and 1B, when the substrates 12 and 13 are bonded at regular positions, the tip of the spacer 15 is Then, the counter substrate 13 contacts with the regular contact position 59 between the protrusions 56 and 56, and the gap d between the substrates 12 and 13 is set to a height dimension h of the spacer 15, for example, 4 μm. At this time, the transmittance t1 between the substrates 12 and 13 is, for example, 0.9 as shown in FIG. Further, the black matrix layer 58 of the counter substrate 13 is positioned so as to overlap the signal line 23 in plan view, and the black matrix layer 58 does not overlap the opening 61 of each subpixel P.

  On the other hand, when the substrates 12 and 13 are bonded to each other, when the bonding positions of the substrates 12 and 13 are shifted by, for example, the horizontal (H) direction by a shift amount Δx, as shown in FIG. Of the protrusion 56 is in contact with the counter substrate 13 side at the flat surface 56b of the protrusion 56, and the gap d between the substrates 12 and 13 is the height h of the spacer 15 and the position where the spacer 15 is in contact. That is, the sum of the protrusion amount p of the protrusion 56 at the position of the shift amount Δx with respect to the center position of the normal contact position 59, for example, 5 μm is set here. At this time, a part of the black matrix layer 58 of the counter substrate 13 protrudes between the signal lines 23 and 23 and overlaps the opening 61 of each sub-pixel P, and the aperture ratio is reduced to, for example, 0.9 times. Further, the transmittance t2 of the liquid crystal layer 14 between the substrates 12 and 13 is, for example, 1.0 as shown in FIG.

  That is, as shown in FIG. 1C, when the bonding position of the substrates 12 and 13 is shifted, the position of the black matrix layer 58 is shifted to the opening 61 side from the regular position, so that the aperture ratio is lowered. . However, by providing the protrusion 56 around the normal contact position 59 on the counter substrate 13 side of the spacer 15 protruding from the array substrate 12, the spacer 15 is protruded by the misalignment of the substrates 12 and 13. Since the gap d between the substrates 12 and 13 is widened, the transmittance T of the liquid crystal layer 14 between the substrates 12 and 13 increases from the transmittance t1 to the transmittance t2, and the positional shift of the substrates 12 and 13 causes A decrease in aperture ratio due to the black matrix layer 58 covering the sub-pixel P can be offset by an increase in transmittance, and a decrease in transmission luminance can be suppressed.

  Specifically, the protrusion 56 is displaced by setting the protrusion amount p so that the transmittance of the liquid crystal layer 14 between the substrates 12 and 13 changes corresponding to the displacement amount Δx from the normal contact position 59. Even when the amount Δx varies, the luminance of the liquid crystal panel 11 can be made uniform by the protrusion amount p of the protrusion 56.

  The amount of deviation Δx between the array substrate 12 and the counter substrate 13 is different for each liquid crystal panel 11 to be manufactured, but it is possible to suppress variations in transmission luminance for each liquid crystal panel 11, thus suppressing variations in characteristics of the liquid crystal panel 11. It is possible to suppress the deterioration of the quality and the yield of the liquid crystal panel 11.

  In the above embodiment, the protrusion 56 can be arbitrarily formed at a position around the normal contact position 59. That is, in the above-described embodiment, when the bonding position of the substrates 12 and 13 is shifted in the horizontal (H) direction, the protrusion 56 is formed so that the tip of the spacer 15 and the protrusion 56 come into contact with each other. However, the protruding portion 56 is sandwiched between the colored portions 52r, 52g, and 52b of the color filter layer 52 so that the tip portion of the spacer 15 and the protruding portion 56 come into contact when displaced in the vertical (V) direction, for example. For example, it may be formed continuously along the horizontal (H) direction on both sides. For example, the tip of the spacer 15 and the protrusion 56 come into contact with each other when they are displaced in the vertical (V) and horizontal (H) directions. As described above, the protrusion 56 may be formed along each of the horizontal (H) direction and the vertical (V) direction.

  Further, when the spacer 15 is formed on the counter substrate 13 side, it can be similarly handled by forming the protrusion 56 on the array substrate 12 side. Further, when the spacer 15 is formed on each of the substrates 12 and 13, it can be similarly handled by forming the protrusion 56 around the normal contact position with the spacer 15 of the other substrate 12 and 13.

11 Liquid crystal panel as a liquid crystal display element
12 Array substrate
13 Counter substrate
14 Liquid crystal layer
15 Spacer as a gap holding member
24 Wiring
25 Thin-film transistors as switching elements
56 Projection
58 Black matrix layer, which is a shading part
59 Normal contact position P Sub-pixel that is a pixel

Claims (2)

An array substrate including a plurality of pixels arranged in a matrix, switching elements for driving the pixels, and wiring connected to the switching elements;
A counter substrate provided with a light-shielding portion at a position corresponding to at least a part of the wiring, which is disposed to be opposed to the array substrate and bonded,
A liquid crystal layer interposed between the array substrate and the counter substrate;
A gap holding member that protrudes from at least one of the array substrate and the counter substrate and holds a gap between the array substrate and the counter substrate by contacting the other of the array substrate and the counter substrate;
A liquid crystal display element, comprising: a projection that is provided on the other of the array substrate and the counter substrate by a translucent member and is located around a normal contact position of the gap holding member. The protrusion amount is set so that the transmittance of the liquid crystal layer changes between the array substrate and the counter substrate in accordance with the amount of deviation from the normal contact position. The liquid crystal display element according to claim 1.

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