JP2009175497A - Liquid crystal display device and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a liquid crystal display device that hardly causes corrosion due to entry of external water, deterioration in display performance, etc., by improving the adhesive strength of a seal material. <P>SOLUTION: The liquid crystal display device includes two transparent substrates 1 and 3 which are arranged opposite each other to hold liquid crystal therebetween, the seal material 2 which is arranged at peripheral portions of the two transparent substrates 1 and 3 to bond the two transparent substrates 1 and 3 to each other, and a black matrix 5 which is disposed between the one transparent substrate 1 and seal material 2, and has a pit- or slit-shaped first level difference structure 8 where it comes into contact with the seal material 2 and an uneven structure 9 on a bottom surface of the first level difference structure 8. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device and a manufacturing method thereof, and more particularly to a liquid crystal display device having improved adhesion strength between an opposing substrate and a sealing material, and a manufacturing method thereof.

  Liquid crystal display devices are widely used as display devices for personal computers and mobile phones as lightweight, compact, and low power consumption display devices. However, since it is used in a wide range, problems may occur when used in special situations. One of the problems is related to the adhesion of the sealing material that adheres the glass substrate. For example, due to a decrease in the adhesion between the substrate and the sealing material, the substrate may be peeled off, or even if the substrate does not peel off, moisture from the outside air may enter the liquid crystal in the panel through the sealing material and cause display defects.

  As techniques that have an improvement effect on these problems, the following Patent Documents 1 to 8 disclose techniques for improving the adhesion of the sealing material. In order to improve the adhesion between the resin black matrix (or the organic flattening film) and the sealing material with particularly poor adhesion, slits or dots are inserted into the black matrix at the portion in contact with the sealing material. As a result, the glass surface and the sealing material can be in direct contact with each other, and the adhesion strength of a normal sealing material can be obtained. For example, in Patent Document 1 below, the adhesive force is improved by forming a resin black matrix with a double structure and forming a stepped portion at a portion where the sealing material contacts.

JP 2001-66609 A JP 2002-229008 A JP 2004-294799 A JP-A-5-72540 JP-A-10-282507 JP-A-11-109380 JP 11-264970 A JP 2002-258261 A

  In general, a black matrix includes a metal light-shielding film made of a laminated film of a chromium oxide film and a chromium film and a resin light-shielding film made of a resin film. However, as described above, the invention described in the above-mentioned patent document is a method for improving the adhesion between the resin black matrix (or organic flattening film) and the sealing material. No method has been proposed for improving the adhesion between the carbon black matrix surface and the sealing material and the glass surface and the sealing material. This is presumably because there are few problems due to insufficient adhesion, and there are few problems due to insufficient adhesion with the sealing material for liquid crystal panels actually made of carbon black matrix.

  However, even in such a liquid crystal panel, for example, when continuous display is performed in a high temperature and high humidity state, moisture in the outside air may enter the liquid crystal panel through the sealing material and cause a display defect. there were.

  Accordingly, the present invention has been made to solve such a problem, and improves the adhesion with a sealing material, and is unlikely to cause corrosion due to intrusion of moisture from the outside, display performance deterioration, etc., and It aims at obtaining the manufacturing method.

  The liquid crystal display device according to the present invention includes two transparent substrates that are disposed to face each other and sandwich the liquid crystal, and a seal that is disposed on a peripheral portion of the two transparent substrates and bonds the two transparent substrates. A pit-shaped or slit-shaped first step structure is disposed between the material and one of the transparent substrate and the sealing material, and is in contact with the sealing material. A black matrix having an uneven structure on the bottom surface.

  A first method for manufacturing a liquid crystal display device according to the present invention is a method for manufacturing a liquid crystal display device in which a liquid crystal is sandwiched between two transparent substrates disposed opposite to each other, on one of the transparent substrates. A step of forming a black matrix; a step of forming a pit-shaped or slit-shaped resist pattern on the black matrix; and etching using the resist pattern as a mask to form a pit-shaped or slit-shaped first pattern on the black matrix. A step structure, and a step of forming an uneven structure on a bottom surface of the first step structure.

  A second method for manufacturing a liquid crystal display device according to the present invention is a method for manufacturing a liquid crystal display device in which a liquid crystal is sandwiched between two transparent substrates arranged opposite to each other, on one of the transparent substrates. A step of forming a pit-shaped or slit-shaped resist pattern, and etching using the resist pattern as a mask, the pit-shaped or slit-shaped second step structure on the transparent substrate, and an uneven surface on the bottom of the second step structure Forming a structure, and forming a black matrix on the transparent substrate.

  According to the liquid crystal display device and the manufacturing method thereof of the present invention, the contact area between the sealing material and the substrate is increased, and the adhesion can be increased. Thereby, the penetration | invasion of the water from the outside can be prevented and reliability can be improved.

<Embodiment 1>
FIG. 1 is a diagram showing a configuration of a liquid crystal display device 20 in the present embodiment. FIG. 1 is a diagram of a liquid crystal display device 20 viewed from the color filter substrate 1 side. The liquid crystal display device 20 includes a color filter substrate 1 in which a color filter is formed on a glass substrate 4 (see FIG. 2), a glass An array substrate 3 in which a thin film transistor (TFT) is formed on a substrate 6 (see FIG. 2), and a sealing material 2 for bonding the color filter substrate 1 and the array substrate 3 are provided. The color filter substrate 1 and the array substrate 3 are bonded to each other with a sealant 2, and liquid crystal is injected into the gap portion to form a liquid crystal panel.

  FIG. 2 is a cross-sectional view of the liquid crystal display device 20 of the present embodiment shown in FIG. 1 cut along the line A-A ′. A cross-sectional configuration of the liquid crystal display device will be described with reference to FIG. The color filter substrate 1 includes a glass substrate 4 (transparent substrate), a plurality of colored layers (not shown) arranged on the glass substrate 4, a black matrix (not shown) weighted between the colored layers, and a glass substrate. 4. A black matrix that is disposed at the peripheral edge of 4 and has a pit-like or slit-like step structure 8 (first step structure) at a position in contact with the sealing material 2, and has a concavo-convex structure 9 on the bottom surface of the step structure 8. And 5.

  On the other hand, the array substrate 3 includes a glass substrate 6 (transparent substrate) and a plurality of signal lines (gate signal lines, source signals) disposed on the glass substrate 6 and electrically connected to a plurality of TFTs (not shown). And a step structure 8 (third step structure) having a pit shape or a slit shape at a position in contact with the sealing material 2 so as to cover the glass substrate 6 including the signal line. And an insulating film 7 having an uneven structure 9 on the bottom surface of the step structure 8. The array substrate 3 may be provided on the glass substrate 6 and may include a light shielding pattern 10 at a position facing the step structure 8 of the color filter substrate 1.

  Next, with reference to FIG. 2, the manufacturing method of the liquid crystal display device 20 in this Embodiment is demonstrated. First, a method for manufacturing the color filter substrate 1 will be described. The color filter substrate 1 of the present embodiment uses a chromium (Cr) black matrix 5. First, a glass substrate 4 serving as a base of the color filter substrate 1 is prepared, a chromium oxide film is formed on the glass substrate 4 by a sputtering method, for example, to a thickness of 20 to 150 nm, and a chromium film is further formed thereon by 50 to 50 nm. It is formed to a thickness of 200 nm. Next, a resist pattern is formed by a normal photolithography method. After the resist pattern is formed, wet etching is performed using an etching solution containing ceric ammonium nitrate and an acid. Thereafter, the resist mask is removed, and the normal black matrix pattern formation is completed.

  Next, a resist pattern opened in a slit shape or a pit shape is formed only in a portion that will later come into contact with the sealing material 2 by a normal photolithography method. Next, half etching (wet etching) is performed using an etching solution containing ceric ammonium nitrate and an acid with the opened resist pattern as a mask. The substrate is immersed in the liquid for a time of 5 to 95%, preferably 10 to 50% of the time for etching the entire chromium film (just etching time).

  By performing half-etching in this way, a step structure 8 is formed in a portion of the black matrix portion that will be in contact with the sealing material 2 later, and a fine uneven structure 9 along the crystal grains of chromium is formed on the bottom surface of the step structure 8. Is done. When the metal is dissolved in the chemical solution, the uneven structure 9 is generally formed because a crystal grain boundary having a large Gibbs free energy is dissolved before the crystal portion. By having the step structure 8 and the concavo-convex structure 9, when the sealing material 2 is bonded later, the bonding area between the sealing material 2 and the color filter substrate 1 is increased, and the adhesion is improved.

  In the case where such a concavo-convex structure 9 is formed, the height of the concavo-convex structure 9 (the height when the glass substrate 4 is down) is lower than the depth of the step structure 8 in order to prevent the occurrence of display defects. It is preferable to form as follows. This is because if the height of the unevenness is higher than the peripheral portion, the height of the spacer in the sealing material 2 becomes unstable, the thickness of the sealing material 2 becomes non-uniform, and this causes display defects. Next, the resist mask is removed by a normal method, and the black matrix 5 is formed.

  After the formation of the black matrix 5 is completed, a color resist is applied, exposed and developed by a normal method, thereby completing R, G, and B colored layers. After the colored layer is formed, a transparent conductive film such as ITO is formed on the front surface of the substrate to form a transparent electrode, an overcoat layer is formed, and the color filter substrate 1 is completed.

  Next, a method for manufacturing the array substrate 3 will be described. As the array substrate 3, one produced by a normal process for forming the TFT array substrate 3 is used. For example, after a plurality of TFTs and a plurality of signal lines are formed on the glass substrate 6, a silicon oxide film or silicon is formed by a CVD (chemical vapar deposition) method or the like so as to cover the signal lines and the glass substrate 6. The insulating film 7 is formed with a nitride film or the like. Further, in order to improve the adhesion between the array substrate 3 and the sealing material 2, it is desirable to form the step structure 8 and the concavo-convex structure 9 on the insulating film 7 of the array substrate 3 in the same manner as the color filter substrate 1 described above. . The method for forming the step structure 8 and the concavo-convex structure 9 is the same as the method described above, and a description thereof will be omitted. The array substrate 3 may be an STN array substrate 3 on which only wiring patterns are formed.

  The array substrate 3 is preferably formed by forming a dummy pattern (light shielding pattern 10) for improving light shielding properties in a region facing the step structure 8 (half-etched pattern) of the color filter substrate 1. This is because the light shielding property of the black matrix 5 is lowered by half-etching, and when this is visually recognized, the image quality is lowered.

  The color filter substrate 1 and the array substrate 3 thus formed are assembled in a normal liquid crystal panel assembly process. For example, the color filter substrate 1 and the array substrate 3 are separately stacked after being subjected to cleaning, alignment film transfer, alignment, and cure baking, and after application of the sealant 2. Thereafter, a liquid crystal panel is completed through steps of thermocompression bonding, substrate cutting, liquid crystal injection, and sealing. Further, a polarizing plate, a driving circuit board, a backlight, and the like are attached to the liquid crystal panel, and the liquid crystal display device 20 is completed.

  Since the liquid crystal display device 20 formed as described above has a large contact area between the sealing material 2 and the substrate (the color filter substrate 1 and the array substrate 3), it has a strong adhesion and is exposed to high temperature and high humidity conditions. However, moisture in the outside air hardly enters and high quality can be maintained.

<Embodiment 2>
Since the configuration of the liquid crystal display device 20 in the present embodiment is the same as that of the first embodiment, the description thereof is omitted. Hereinafter, a manufacturing method of the liquid crystal display device 20 in the present embodiment will be described with reference to FIG. First, a method for manufacturing the color filter substrate 1 will be described. The color filter substrate 1 of the present embodiment uses an organic resin black matrix 5. First, a glass substrate 4 serving as a base of the color filter substrate 1 is prepared, and a black matrix of an organic resin is formed on the glass substrate 4 with a film thickness of 0.1 to 10 μm, preferably 1 to 3 μm, for example, by photolithography. .

  Next, a positive resist pattern opened in a slit shape or a pit shape is formed only in a portion which will be in contact with the sealing material 2 later by an ordinary photolithography method. Next, half etching is performed by a normal dry etching method. The etching time is desirably such that the film thickness of the remaining organic resin film in the black matrix portion is 5 to 95%, preferably 50 to 99%.

  By performing half-etching in this way, a step structure 8 (third step structure) is formed in a portion where the black matrix portion will be in contact with the sealing material 2 later, and a fine uneven structure 9 is formed on the bottom surface of the step structure 8. Is done. By having the step structure 8 and the concavo-convex structure 9, when the sealing material 2 is bonded later, the bonding area between the sealing material 2 and the color filter substrate 1 is increased, and the adhesion is improved.

  In the case where such a concavo-convex structure 9 is formed, the height of the concavo-convex structure 9 (the height when the glass substrate 4 is down) is lower than the depth of the step structure 8 in order to prevent the occurrence of display defects. It is preferable to form as follows. This is because if the height of the unevenness is higher than the peripheral portion, the height of the spacer in the sealing material 2 becomes unstable, the thickness of the sealing material 2 becomes non-uniform, and this causes display defects. Next, the resist mask is removed by a normal method, and the black matrix 5 is formed. Since the subsequent steps are the same as those in the first embodiment, description thereof is omitted. Further, since the method for manufacturing the array substrate 3 is the same as that in the first embodiment, the description thereof is omitted.

  Since the liquid crystal display device 20 formed as described above has a large contact area between the sealing material 2 and the substrate (the color filter substrate 1 and the array substrate 3), it has a strong adhesion and is exposed to high temperature and high humidity conditions. However, moisture in the outside air hardly enters and high quality can be maintained.

<Embodiment 3>
FIG. 3 is a cross-sectional view of the liquid crystal display device 20 of the present embodiment shown in FIG. 1 cut along the line AA ′. A cross-sectional configuration of the liquid crystal display device 20 will be described with reference to FIG. The color filter substrate 1 includes a glass substrate 4 (transparent substrate) having a pit-shaped or slit-shaped step structure 11 (second step structure) at the peripheral portion and a concavo-convex structure 12 on the bottom surface of the step structure 11, glass A plurality of colored layers (not shown) arranged on the substrate 4, a black matrix (not shown) filled between the colored layers, and the step structure 11 of the glass substrate 4, which are in contact with the sealing material 2. A black matrix 5 having a pit-shaped or slit-shaped step structure 8 at a position and a concavo-convex structure 9 on the bottom surface of the step structure 8 is provided.

  On the other hand, the array substrate 3 has a glass substrate 6 (transparent substrate) having a pit-shaped or slit-shaped step structure 11 (fourth step structure) at the peripheral portion and a concavo-convex structure 12 on the bottom surface of the step structure 11, and glass. A plurality of signal lines (gate signal lines, source signal lines, not shown) disposed on the substrate 6 and electrically connected to a plurality of TFTs (not shown), and on the glass substrate 6 including the signal lines An insulating film 7 having a pit-like or slit-like step structure 8 (third step structure) at a position in contact with the sealing material 2 and having a concavo-convex structure 9 on the bottom surface of the step structure 8. And. The array substrate 3 may be provided on the glass substrate 6 and may include a light shielding pattern 10 at a position facing the step structure 8 of the color filter substrate 1.

  Next, with reference to FIG. 3, the manufacturing method of the liquid crystal display device 20 in this Embodiment is demonstrated. First, a method for manufacturing the color filter substrate 1 will be described. In the color filter substrate 1 of the present embodiment, the step structure 11 is formed before the black matrix 5 is formed. First, a glass substrate 4 that serves as a foundation for the color filter substrate 1 is prepared, and a resist that is opened in a slit shape or a pit shape on the glass substrate 4 only in a portion that will later come into contact with the sealing material 2 by a normal photolithography method. Form a pattern. Next, the step structure 11 is formed on the glass substrate 4 and the concavo-convex structure 12 is formed on the bottom surface of the step structure 11 by dry etching or wet etching. The depth of the step structure 11 is about 0.01 to 10 μm, preferably about 0.03 to 1 μm. The width of the slit and the diameter of the pits should be smaller than the width of the sealing material 2 (usually 1 mm). Specifically, it is preferably about 3 to 500 μm, which is the limit of photolithography technology. Next, the resist mask is removed by a normal method, and the glass substrate 4 is formed. Here, the method of forming the step structure 11 by a general photoengraving method has been described. However, the method of forming the step structure 11 may be, for example, a method using a laser beam or a method of directly applying an etching solution by an ink jet method. .

  Next, a black matrix is formed by a normal method. For example, in the black matrix method, a chromium oxide film is formed to a thickness of 20 to 150 nm on the glass substrate 4 by sputtering, and a chromium film is further formed to a thickness of 50 to 200 nm thereon. Next, a resist pattern is formed by a normal photolithography method. After the resist pattern is formed, wet etching is performed using an etching solution containing ceric ammonium nitrate and an acid. Thereafter, the resist mask is removed, and pattern formation of the normal black matrix 5 is completed.

  By doing so, the step structure 11 and the concavo-convex structure 12 of the glass substrate 4 are reflected in the portion of the black matrix 5 that will be in contact with the sealing material 2 later, and the step structure 8 and the concavo-convex structure 9 are formed. Thereby, when adhesion | attachment by the sealing material 2 is performed later, the contact area of the sealing material 2 and the color filter substrate 1 becomes large, and adhesive force improves.

  Up to this point, the method of forming the black matrix 5 using chromium has been described, but the present invention can also be applied to the formation of the black matrix 5 using an organic resin. In this case, since the organic resin hardly reflects the underlying concavo-convex structure 12, it is preferable not to form an organic resin pattern in the concavo-convex structure 12 portion. After the pattern formation of the black matrix 5 is completed, the description is omitted because it is the same as that of the first embodiment.

  Next, a method for manufacturing the array substrate 3 will be described. First, a glass substrate 6 as a base of the array substrate 3 is prepared, and a resist pattern opened in a slit shape or a pit shape is formed on the glass substrate 6 at a portion that will later come into contact with the sealing material 2 by a normal photolithography method. To do. Next, dry etching or wet etching is performed to form a step structure 11 on the glass substrate 6 and an uneven structure 12 on the bottom surface of the step structure 11. The depth of the step structure 11 is about 0.01 to 10 μm, preferably about 0.03 to 1 μm. The slit width and dot diameter should be smaller than the seal width (usually 1 mm). Specifically, it is preferably about 3 to 500 μm, which is the limit of photolithography technology. After the etching, the resist is removed by a normal method, and the glass substrate 6 having the step structure 11 and the concavo-convex structure 12 is formed. Here, the method of forming the step structure 11 by a general photoengraving method has been described. However, the method of forming the step structure 11 may be, for example, a method using a laser beam or a method of directly applying an etching solution by an ink jet method. . When the step structure 11 is formed on the glass substrate 6 of the array substrate 3, it is preferable not to form the step structure 11 in the wiring portion in order to avoid disconnection of the wiring portion.

  When the normal array substrate 3 manufacturing process is performed on the glass substrate 6, the step structure 11 of the glass substrate 6 is formed in the insulating film 7 portion and the portion that will be in contact with the sealing material 2 later, as in the color filter substrate 1 described above. And the uneven structure 12 is reflected, and the step structure 8 and the uneven structure 9 are formed. Thereby, when adhesion | attachment by the sealing material 2 is performed later, the contact area of the sealing material 2 and the array board | substrate 3 becomes large, and adhesive force improves. Other steps are the same as those in the first embodiment, and thus description thereof is omitted.

  Since the liquid crystal display device 20 formed as described above has a large contact area between the sealing material 2 and the substrate (the color filter substrate 1 and the array substrate 3), it has a strong adhesion and is exposed to high temperature and high humidity conditions. However, moisture in the outside air hardly enters and high quality can be maintained.

It is the figure which showed the structure of the liquid crystal display device in Embodiment 1 of this invention. It is sectional drawing which showed the structure of the liquid crystal display device in Embodiment 1 of this invention. It is sectional drawing which showed the structure of the liquid crystal display device in Embodiment 3 of this invention.

Explanation of symbols

  1 color filter substrate, 2 sealing material, 3 array substrate, 4,6 glass substrate, 5 black matrix, 7 insulating film, 8, 11 step structure, 9, 12 uneven structure, 10 light shielding pattern.

Claims (10)

Two transparent substrates disposed opposite to each other and holding the liquid crystal;
A sealing material disposed on a peripheral portion of the two transparent substrates and bonding the two transparent substrates;
One of the transparent substrate and the sealing material is disposed between the transparent material and has a pit-shaped or slit-shaped first step structure at a position in contact with the sealing material, and the bottom surface of the first step structure is uneven. And a black matrix having a structure.   The one transparent substrate has a pit-shaped or slit-shaped second step structure below the first step structure of the black matrix, and has a concavo-convex structure on the bottom surface of the second step structure. The liquid crystal display device according to claim 1.   3. The liquid crystal display device according to claim 1, further comprising a light shielding pattern disposed on a region of the other transparent substrate on the other transparent substrate and facing the first step structure of the black matrix.   A third step structure having a pit shape or a slit shape is provided between the other transparent substrate and the sealing material, and is in contact with the sealing material, and the bottom surface of the third step structure is uneven. The liquid crystal display device according to claim 1, further comprising an insulating film having a structure.   The other transparent substrate has a pit-shaped or slit-shaped fourth step structure below the third step structure of the insulating film, and has a concavo-convex structure on the bottom surface of the fourth step structure. The liquid crystal display device according to claim 4.   The liquid crystal display device according to claim 1, wherein the concavo-convex structure is formed such that a height of the concavo-convex is lower than a depth of the step structure. A method of manufacturing a liquid crystal display device in which a liquid crystal is sandwiched between two transparent substrates disposed opposite to each other,
Forming a black matrix on one of the transparent substrates;
Forming a pit-shaped or slit-shaped resist pattern on the black matrix;
Etching using the resist pattern as a mask, and forming a pit-shaped or slit-shaped first step structure on the black matrix, and forming a concavo-convex structure on the bottom surface of the first step structure. Method. Forming an insulating film on the other transparent substrate;
Forming a pit-like or slit-like resist pattern on the insulating film;
The method further comprises: etching using the resist pattern as a mask to form a pit-shaped or slit-shaped third step structure in the insulating film, and forming a concavo-convex structure on a bottom surface of the third step structure. The manufacturing method of the liquid crystal display device of description. A method of manufacturing a liquid crystal display device in which a liquid crystal is sandwiched between two transparent substrates disposed opposite to each other,
Forming a pit-shaped or slit-shaped resist pattern on one of the transparent substrates;
Etching using the resist pattern as a mask, forming a pit-shaped or slit-shaped second step structure on the transparent substrate, and forming a concavo-convex structure on the bottom surface of the second step structure;
And a step of forming a black matrix on the transparent substrate. Forming a pit-shaped or slit-shaped resist pattern on the other transparent substrate;
Etching using the resist pattern as a mask, forming a pit-shaped or slit-shaped fourth step structure on the transparent substrate, and forming a concavo-convex structure on the bottom surface of the fourth step structure;
The method for manufacturing a liquid crystal display device according to claim 9, further comprising: forming an insulating film on the transparent substrate.

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