JP2005189360A - Liquid crystal display device and method for manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To repair a bright spot defect without requiring a special device or a complicated operation and without running into a trouble of air bubble formation between a polarizing plate and a liquid crystal panel. <P>SOLUTION: A recessed part 4 is formed on a point which is located on the surface of at least one substrate 3 (upper side) out of a pair of substrates 3, 3 placed opposite to each other, opposite to a liquid crystal layer 9, and directly above a part 1 where the bright spot defect is produced in a display region. A light shielding paint 6 is applied to the inside of the recessed part 4, and subsequently curable resin 7 is poured into the recessed part 4 where light shielding paint 6 is applied in advance and temporarily cured. The surface is flattened by scraping the resin part 7a protruding from the surface so as to form a flattened part 8. Then the curable resin 7 is completely cured. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a liquid crystal display device in which a bright spot defect of a minute pixel generated in a display region is corrected, and a manufacturing method thereof.

  In this type of liquid crystal display device, a display screen is configured in which a liquid crystal layer is sandwiched between a pair of opposed substrates and a plurality of pixel portions are formed in a matrix. By switching between applying and not applying voltage to the liquid crystal layer of each pixel part of this display screen, the orientation state of the liquid crystal molecules is changed within each pixel part, and thereby the light transmission / scattering state of each pixel part Is modulated, and characters and images are displayed on the display screen.

  In this liquid crystal display device, for example, in the normally black mode in which black display is obtained when no voltage is applied to the liquid crystal layer, wiring and electrodes are short-circuited in each pixel portion, TFT (thin film transistor) as a pixel switching element, etc. If the voltage remains applied to the liquid crystal layer of the pixel portion, the pixel portion is displayed as a fine luminescent spot. In the normally white mode in which white display can be obtained when no voltage is applied to the liquid crystal layer, wiring or electrodes are disconnected in each pixel portion, TFT malfunctions, etc., and no voltage is applied to the liquid crystal layer in the pixel portion. Then, that portion is displayed as a fine bright spot.

  Conventionally, when such a bright spot failure occurs, the laser device is used to irradiate the disconnection portion or the short-circuit portion, and the disconnection portion is connected or short-circuited by a correction wire provided in advance. Defect correction is performed by cutting a part.

  However, when foreign matter or the like adheres to the substrate surface and alignment disorder occurs in the liquid crystal layer, light leakage occurs and a bright spot is defective, such correction by laser light irradiation cannot be performed.

For this reason, for example, in Patent Document 1, a concave portion is formed on the surface of the pixel portion where a bright spot defect has occurred on the opposite side of the liquid crystal layer of at least one of the pair of substrates, and the concave portion is formed in the concave portion. A method of filling a light-shielding resin to make the bright spot defect inconspicuous is disclosed. In this prior art, a recess is formed in a state where a covering member is formed on the surface of the substrate, and a relatively large amount of light-shielding resin is filled in the recess so that the recess is sufficiently filled with the light-shielding resin, and from within the recess. This prevents the light-blocking resin from overflowing. Further, the thickness of the light shielding resin is adjusted by adjusting the thickness of the covering member.
JP-A-5-210074

  The above-mentioned conventional bright spot defect correcting method for correcting a bright spot defect using laser light requires special equipment and technology such as a laser light irradiation device, depending on the equipment cost and maintenance cost of the laser light irradiation device, etc. There is a problem that the correction cost increases. In addition, in the above-described conventional bright spot defect correcting method using laser light irradiation, a bright spot defect cannot be corrected when a bright spot defect occurs due to adhesion of foreign matter or the like.

  In the conventional bright spot defect correcting method disclosed in Patent Document 1, the correction work is complicated by providing a special covering member on the substrate surface. Even when this covering member is used, if the light-shielding resin filled in the recesses rises from the substrate surface to form protrusions, the protrusions are formed when the polarizing plates are bonded to both outer sides of the substrate. There is a problem that air bubbles are generated between the polarizing plate and the substrate (liquid crystal panel) due to the portion.

  The present invention solves the above-described conventional problems, does not require a special device such as a laser beam irradiation device or complicated correction work, and bubbles are generated between the polarizing plate and the liquid crystal panel. It is an object of the present invention to provide a liquid crystal display device in which a defective bright spot is corrected and a method for manufacturing the same without causing defects.

  The liquid crystal display device of the present invention is a liquid crystal display device in which a liquid crystal layer is sandwiched between a pair of opposed substrates, and at least one of the pair of substrates is opposite to the liquid crystal layer side. A concave portion is formed at a surface position that is optically overlapped with a portion where a bright spot defect is occurring, a light shielding material is provided in the concave portion, and a curable resin is provided in the concave portion provided with the light shielding material. And the surface is flattened, whereby the above object is achieved.

  The method for manufacturing a liquid crystal display device according to the present invention corrects a bright spot defect that corrects a bright spot defect in the display area of a liquid crystal display device in which a liquid crystal layer is sandwiched between a pair of substrates arranged opposite to each other. In a method of manufacturing a liquid crystal display device including a step (bright spot defect correcting method), a surface position on the opposite side of the liquid crystal layer side of at least one of the pair of substrates, A recess forming step of forming a recess at a surface position optically overlapping the generated portion, a light shielding material arranging step of providing a light shielding material in the recess, and pouring a curable resin into the recess provided with the light shielding material. And a curable resin temporary curing step that is temporarily cured at the same time, thereby achieving the above object.

  Preferably, in the step of forming a recess in the method for manufacturing a liquid crystal display device of the present invention, the recess is formed by pressing the tip of the pen tip means with a diamond head against the surface position and boring.

  Furthermore, preferably, the recess in the method for manufacturing a liquid crystal display device of the present invention is the same size as the pixel portion.

  Furthermore, preferably, after the curable resin temporary curing step in the method for manufacturing a liquid crystal display device of the present invention, the method further includes a flattening step of scraping off the raised surface of the temporarily cured curable resin to flatten the surface.

  Further preferably, in the planarization step in the method of manufacturing a liquid crystal display device of the present invention, the surface of the curable resin having a hardness of 96 or more and less than 100 is scraped off.

  Furthermore, preferably, after the planarization process in the manufacturing method of the liquid crystal display device of this invention, it further has the curable resin main-curing process of carrying out the main curing of the said curable resin.

  More preferably, a two-component curable resin is used as the curable resin in the method for producing a liquid crystal display device of the present invention.

  Further preferably, the curable resin in the method for producing a liquid crystal display device of the present invention has a glass transition temperature of 65 degrees Celsius ± 10 degrees Celsius.

  Further preferably, in the curable resin temporary curing step in the method of manufacturing a liquid crystal display device of the present invention, the curable resin is heated at 60 degrees Celsius for 150 minutes, and then left at room temperature for 10 minutes, not exceeding 50 minutes. In the meantime, the planarization step is finished.

  With the above configuration, the operation of the present invention will be described below.

  In the present invention, at least one of the pair of substrates disposed opposite to each other with the liquid crystal layer interposed therebetween is a surface on the opposite side of the liquid crystal layer side from the portion where the bright spot defect occurs and optical For example, by pressing a pen tip means equipped with a diamond head at a position where the diamond head is mounted and boring the substrate surface made of glass or the like, a minute recess is formed in units of pixels, and a light shielding material (for example, After providing (applying light-shielding paint), a curable resin such as a two-component curable resin is poured into the recess and cured. Thereby, it is possible to make the pixel portion where the bright spot defect is inconspicuous without requiring special equipment such as a laser beam irradiation device or complicated work.

  In addition, by scraping the cured resin surface and flattening the surface, no bubbles are generated between the liquid crystal panel and the polarizing plate, and the display state of the display screen is improved. it can.

  This curable resin can improve the correction efficiency by scraping the surface with a cutter blade or the like in a pre-cured and easy-to-shave state, followed by main curing.

  As described above, according to the present invention, even when alignment defects occur in the liquid crystal layer due to foreign matter or the like and a luminescent spot defect occurs, a minute luminescent spot defect is shielded without using special equipment such as a laser beam irradiation device. It is possible to make the display inconspicuous by shielding light with a material (for example, light shielding paint). In addition, it is possible to correct bright spot defects caused by contamination of foreign matters that could not be corrected by conventional laser light irradiation.

  In addition, by flattening the surface of the substrate with a curable resin, the display quality of the liquid crystal display device is further improved without causing problems such as bubbles entering between the polarizing plate and the liquid crystal panel to be attached afterwards. Can be made.

  Embodiments of a liquid crystal display device and a manufacturing method thereof according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a flowchart for explaining a bright spot defect correcting method for a liquid crystal display device according to an embodiment of the present invention, FIG. 2 is a plan view for explaining step 1 in FIG. 1, and FIGS. It is sectional drawing for demonstrating each step of FIG.

  In the manufacture of a liquid crystal display device, a pair of substrates (for example, a TFT element side substrate and a counter substrate) are disposed to face each other and bonded together, and a liquid crystal layer is sealed between the two substrates. When a bright spot defect is detected, first, as shown in FIG. 1, in step S1, the person in charge of correction corrects the minute bright spot defect occurrence portion 1 as shown in FIG. Marking 2 is applied by magic or the like. A minute bright spot defective portion is specified with respect to the marking 2 portion using a polarizing plate or the like.

  Next, in step S2, as shown in FIG. 3, at least one of the pair of substrates 3 (for example, the upper substrate) is a surface opposite to the liquid crystal layer 9 side and has a defective bright spot. The concave portion 4 is formed at a position corresponding to the portion where the occurrence occurs (surface position optically overlapping). In this embodiment, a bright spot failure portion is observed using a magnifying glass, and a pen tip 5 as a pen tip means in which a diamond head is mounted on the surface of one glass substrate 3 directly above the bright spot failure portion 1. The concave part 4 is produced by pressing the tip of and performing a boring operation. In this case, it is preferable to use a pen nib 5 having a sharp tip. Thereby, for example, the recess 4 having a depth of about 200 μm to 300 μm is formed. The size of the concave portion does not exceed the size of the pixel portion in plan view, and the shape may be circular or rectangular.

  Further, in step S3, a light shielding paint 6 as a light shielding material is applied in the recess 4 as shown in FIG. For this shading paint, a color such as black or gray is selected according to the purpose.

  Further, in step S4, as shown in FIG. 5, a curable resin 7 (for example, a light-shielding resin) may be poured onto the portion where the light-shielding paint 6 is applied in the recess 4 formed immediately above the bright spot portion 1. .

  For example, a two-component curable resin can be used as the curable resin 7. If the curing time of the curable resin 7 is too short, the range of the bright spot defect correction work time is limited, and the failure rate of the bright spot defect correction becomes high. In addition, if the curing time of the curable resin 7 is too long, it takes too much time for correction, and thus lacks practicality.

  Therefore, it is preferable to use a curable resin having such a hardness that the resin can be easily shaved by a cutter or the like in step S6 described later in the course of curing the curable resin 7 in step S5, that is, in the middle of curing of the curable resin 7. . In addition, even if the curable resin is cured, if the adhesion to the glass is not maintained, problems such as resin peeling occur when the polarizing plate and the liquid crystal panel are bonded together, resulting in a glass transition of the resin. It is preferable to improve the adhesion to glass. At this time, if the glass transition temperature of the resin is too high, it may be adversely affected on a liquid crystal panel, a polarizing plate, and the like. Therefore, it is preferable to use a curable resin that causes glass transition at a low temperature of about 60 ° C.

  For example, when a two-component curing resin (EPO-TEK301 manufactured by Epoxy Technology) is used, the curing time at room temperature (25 ° C.) is 2 days, and the glass transition temperature is 65 ° C. ± 10 ° C., which is used in the present invention. Suitable as a curable resin. Hereinafter, a correction method when this curable resin is used will be described. When pouring this curable resin, it is preferable to place the resin in the recess 4 using a needle or the like.

  In step S5, in order to shorten the correction time, the liquid crystal display device is put into a high temperature bath (60 ° C.), and the curable resin is temporarily cured. At this time, it is necessary to set an appropriate condition for the temporary curing time of the curable resin depending on the properties of the resin used for correction.

  FIG. 7 shows the elapsed time (curing time) used for determining the temporary curing time and the resin cutting work time for the curable resin (Epo-Technology EPO-TEK301) used in the present embodiment and the ease of resin cutting. It is a graph which shows a relationship.

  As shown in FIG. 7, the vertical axis represents the resin hardness measured with a rubber / plastic A type hardness tester (A type testing machine GS706N), and the horizontal axis represents the resin curing time. The square points shown by squares are the hardness measured every 5 minutes when the resin is kept warmed at 60 ° C., and the round dots shown by circles are heated at 60 ° C. for 150 minutes and then left at room temperature for 10 minutes. The rhombus points indicated by rhombuses are the hardness measured every 5 minutes after the resin was warmed at 50 ° C. for 150 minutes and then allowed to stand at room temperature for 10 minutes.

  As shown by the square points in FIG. 7, when the resin is kept warm at 60 ° C., the hardness of the resin becomes 96 after an elapsed time of 160 minutes, and thereafter the resin gradually becomes harder and the hardness of the resin after an elapsed time of 200 minutes. Is 100. Also, as shown by the round dots in FIG. 7, after the resin was warmed at 60 ° C. for 150 minutes and then allowed to stand at room temperature for 10 minutes, the resin had a hardness of 96 at an elapsed time of 160 minutes (immediately after being left at room temperature for 10 minutes). Since then, the resin has gradually become hard and has a hardness of 100 after an elapsed time of 210 minutes (after 10 minutes at room temperature and after 50 minutes). In addition, as shown by the rhombus points in FIG. 7, after warming the resin at 50 ° C. for 150 minutes and leaving it to stand at room temperature for 10 minutes, the resin reaches the elapsed time of 165 minutes (after standing for 10 minutes at room temperature and 5 minutes have passed). The hardness of the resin gradually increased to 96, and thereafter, the resin gradually hardened and reached a hardness of 100 after an elapsed time of 240 minutes (after standing for 10 minutes at room temperature and 90 minutes).

  Since the hardness at which the resin is easily scraped is 96 or more and less than 100, in this embodiment, the time for temporarily curing the resin at a temperature of 60 ° C. in step S5 is 160 minutes, and the time for scraping the cured resin in step S6 is the high temperature bath After natural cooling for 10 minutes after taking out (temporary curing time; 160 minutes), it was set to less than 50 minutes.

  After the liquid crystal display device is taken out from the high temperature bath, the liquid crystal display device is naturally cooled for 10 minutes in order to cool down to a workable temperature because the panel surface is hot.

  Thereafter, in step S6, the curable resin is shaved to flatten the surface. In this embodiment, after natural cooling, the curable resin portion 7a raised from the glass surface is scraped off with a cutter blade within 50 minutes when the resin is in a state where it can be easily cut, and the curable resin as shown in FIG. Is flattened (flat portion 8).

  In this way, it is possible to reduce the failure rate of correction by checking whether the resin is scraped off after the resin is scraped off.

  Further, in step S7, the liquid crystal display device is again put into a high temperature bath (60 ° C.) for 180 minutes to complete the main curing of the curable resin.

  By performing the correction as described above, at least one of the pair of substrates 3 and 3 arranged opposite to each other, the surface of the substrate 3 opposite to the liquid crystal layer 9 is directly above the bright spot defective portion 1 (or (And directly below) a recess 4 is formed, and a light-shielding paint 6 is applied in the recess 4, and the minute bright spot defective portion 1 is shielded by the light-shielding paint 6, so that the bright spot defect is inconspicuous. Can do. Further, since the concave portion 4 is filled with a curable resin and the surface thereof is flattened (flat portion 8), the display quality is deteriorated due to the generation of bubbles between the polarizing plate and the liquid crystal panel to be attached thereafter. Can be prevented and the display quality can be improved.

  In this embodiment, the concave portion 4 is formed on the surface of the pair of substrates 3 (upper side) opposite to the liquid crystal layer 9, but may be formed on the other substrate 3 (lower side). It may be formed on the substrates 3 and 3. Further, the method for forming the recesses 4 is not limited to the above-described method, and any method can be used as long as it can accurately form the minute recesses 4 in pixel units. Further, the curable resin is not limited to the two-component property described above, and various resins such as an ultraviolet curable resin and a thermosetting resin can be used.

  In the case of an ultraviolet curable resin, an ultraviolet irradiation facility is required, and management of the facility is also required. On the other hand, in the case of a two-component curable resin, there is an effect that such extra equipment can be omitted.

  As mentioned above, although this invention has been illustrated using preferable embodiment of this invention, this invention should not be limited and limited to this embodiment. It is understood that the scope of the present invention should be construed only by the claims. It is understood that those skilled in the art can implement an equivalent range based on the description of the present invention and the common general technical knowledge from the description of specific preferred embodiments of the present invention. Patents, patent applications, and documents cited herein should be incorporated by reference in their entirety, as if the contents themselves were specifically described herein. Understood.

  The present invention relates to a bright spot defect correcting method for correcting a minute bright spot defect occurring in a pixel region, and in the field of a liquid crystal display device in which the bright spot defect is corrected by the method, the minute bright spot defect is inconspicuous. In addition, it is possible to improve the display quality of the liquid crystal display device without generating bubbles when the liquid crystal panel and the polarizing plate are bonded to each other. The bright spot defect correction work can be efficiently performed at low cost without using special equipment or complicated work. The liquid crystal display device in which the bright spot defect is corrected according to the present invention has a good display quality, and the light leakage caused by the alignment failure of the liquid crystal layer due to foreign matter, etc., which cannot be corrected by laser irradiation or the like, becomes inconspicuous. Therefore, the manufacturing yield can be greatly improved.

It is a flowchart for demonstrating the bright spot defect correction method of the liquid crystal display device which is one Embodiment of this invention. It is a top view which shows the state which performed the marking by the magic in step S1 of FIG. It is principal part sectional drawing which shows the part which produced the recessed part at FIG.1 S2. It is principal part sectional drawing which shows the state which applied the light-shielding coating material by step S3 of FIG. It is principal part sectional drawing which shows the state which apply | coated the cured resin at step S4 of FIG. It is principal part sectional drawing which shows the state which shaved hardened resin in FIG.1 S6, and planarized the surface. In order to set the conditions of the temporary curing time of the curable resin used in the bright spot defect correcting method of FIG. 1 (temporary curing processing time in step S5) and the resin shaving operation time, the curing time and the hardness of the curable resin are set as follows. It is a graph which shows the result of examining a relationship.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Minute bright spot defective part 2 Marking part by magic 3 A pair of glass substrate which comprises a liquid crystal panel 4 The recessed part formed by boring 5 Pen with which the diamond head for boring was mounted | worn (pen nib means)
6 Shading paint (shading material)
7 curable resin 7a curable resin portion rising from surface 8 flat portion of curable resin scraped off 9 liquid crystal layer

Claims (10)

In a liquid crystal display device in which a liquid crystal layer is sandwiched between a pair of opposed substrates,
A concave portion is formed at a surface position on the opposite side of the liquid crystal layer side of at least one of the pair of substrates and optically overlapping a portion where a bright spot defect occurs, and the concave portion A liquid crystal display device in which a light-shielding material is provided, and a concave portion provided with the light-shielding material is filled with a curable resin to flatten the surface. In a manufacturing method of a liquid crystal display device including a bright spot defect correcting step of correcting a bright spot defect when a defective bright area occurs in a display region of a liquid crystal display device in which a liquid crystal layer is sandwiched between a pair of substrates arranged opposite to each other,
The bright spot defect correcting step is:
Forming a recess at a surface position on the opposite side of the liquid crystal layer side of at least one of the pair of substrates and forming a recess at a surface position that optically overlaps the portion where the bright spot defect has occurred Process,
A light shielding material arranging step of providing a light shielding material in the recess;
A method for producing a liquid crystal display device, comprising: a curable resin temporary curing step in which a curable resin is poured into a recess provided with the light shielding material and temporarily cured.   3. The method of manufacturing a liquid crystal display device according to claim 2, wherein in the recess forming step, the recess is formed by pressing a tip portion of a pen tip means attached with a diamond head against the surface position and boring.   The method for manufacturing a liquid crystal display device according to claim 2, wherein the concave portion has the same size as the pixel portion.   The method for manufacturing a liquid crystal display device according to claim 2, further comprising a flattening step of scraping off a raised surface of the temporarily cured curable resin after the curable resin temporary curing step to flatten the surface.   The method of manufacturing a liquid crystal display device according to claim 5, wherein in the planarization step, a surface of a curable resin having a hardness of 96 or more and less than 100 is scraped off.   The method for manufacturing a liquid crystal display device according to claim 5, further comprising a curable resin main-curing step of main-curing the curable resin after the planarization step.   The method for manufacturing a liquid crystal display device according to claim 2, wherein a two-component curable resin is used as the curable resin.   The method of manufacturing a liquid crystal display device according to claim 2, wherein the curable resin has a glass transition temperature of 65 degrees Celsius ± 10 degrees Celsius. In the curable resin temporary curing step, the curable resin is heated at 60 degrees Celsius for 150 minutes, and then allowed to stand at room temperature for 10 minutes, and the planarization step is finished before exceeding 50 minutes. A method for producing a liquid crystal display device according to any one of the above.