JP2010134030A - Liquid crystal display device and method for manufacturing the same - Google Patents

Abstract

A liquid crystal display device in which occurrence of counter leakage is suppressed is provided.
A liquid crystal display device according to the present invention includes an active matrix substrate having pixel electrodes, a gate bus line and a source bus line arranged in a matrix, an active matrix substrate and a liquid crystal layer. And a counter substrate 4 having a black matrix 44 and a counter electrode 43. The black matrix 44 is formed of a resin, and the counter electrode 43 is formed between the black matrix 44 and the glass substrate 41 in a region where the black matrix 44 and the counter electrode 43 overlap.
[Selection] Figure 1

Description

  The present invention relates to a liquid crystal display device such as a liquid crystal display and a method for manufacturing the same.

  Liquid crystal display devices are widely used in liquid crystal televisions, monitors, mobile phones, and the like, taking advantage of energy saving, thinness, and light weight.

  FIG. 4 is a cross-sectional view showing an embodiment of a liquid crystal display device 100 having a non-SHA (Super High Aperture) structure.

  As shown in FIG. 4, the liquid crystal display device 100 includes a switching element such as a thin film transistor, an active matrix substrate 102 in which a plurality of source bus lines 123 and gate bus lines are formed on a transparent substrate, a color filter layer 142 of multiple colors, black It has a counter substrate 104 on which a matrix 144 and a common electrode 143 are formed, and a liquid crystal layer 106 interposed between the two substrates.

  Conventionally, in the liquid crystal display device 100 having the above-described configuration, when current leakage occurs in the thin film transistor, there is a problem in that image quality deterioration such as a reduction in screen contrast occurs.

  Therefore, in order to solve this problem, for example, the opening shape of the counter substrate is arranged inside the metal electrode on the thin film transistor substrate side, and the liquid crystal that completely shields the channel portion, gate electrode, and source electrode of the thin film transistor from the counter substrate side A panel has been developed and disclosed in US Pat. According to this liquid crystal panel, light reaching the channel portion of the thin film transistor is suppressed, and occurrence of leakage due to light can be suppressed.

  In addition, when an electrical short circuit (upper and lower leakage) occurs between both substrates, problems such as pixel defects such as bright spots and black spots have occurred.

In order to solve this problem, in the liquid crystal display device disclosed in Patent Document 2, the gate electrode and the source electrode are covered with a thick interlayer insulating film on the substrate side on which the thin film transistor is formed. This prevents an electrical short circuit between the two substrates via the gate electrode and the source electrode.
JP 4-204420 (published July 24, 1992) Japanese Patent Laid-Open No. 9-80416 (published March 28, 1997)

  In the non-SHA structure picture element, the distance between the source bus line on the active matrix substrate and the transparent electrode on the counter substrate is short. For this reason, as shown in FIG. 5, in the manufacturing process of the liquid crystal display device 100, when the foreign matter 170 enters the liquid crystal layer 106 and the source bus line 123, the foreign matter 170 also contacts and faces the common electrode 143. There is a high possibility that leakage occurs between the substrates 104 and 102.

  However, in the liquid crystal panel described in Patent Document 1, the occurrence of leak due to light can be suppressed, but the leak between the opposing substrates 104 and 102 caused by the inclusion of the foreign matter 170 as shown in FIG. 5 is considered. Not.

  Further, in the liquid crystal display device described in Patent Document 2, the gate electrode and the source electrode are covered with a thick interlayer insulating film, thereby preventing the occurrence of the leakage caused by the foreign matter mixed in the liquid crystal layer. However, in recent years, further improvement in production capacity of liquid crystal display devices is desired, and development of a means for preventing leakage between opposing substrates using a simpler configuration is desired.

  Accordingly, the present invention has been made in view of the above-described problems, and an object of the present invention is to provide a new liquid crystal display device in which the occurrence of leakage between opposing substrates is suppressed.

  In order to solve the above problems, a liquid crystal display device according to the present invention includes a first substrate on which pixel electrodes, gate bus lines, and source bus lines arranged in a matrix are formed, the first substrate, and a liquid crystal In a liquid crystal display device having a second substrate on which a black matrix and a transparent electrode are formed on a side facing the first substrate, the black matrix is formed of a resin. In the region where the black matrix and the transparent electrode overlap, the transparent electrode is formed between the black matrix and the second substrate.

  According to the above configuration, the liquid crystal display device includes the first substrate and the second substrate facing each other, and the liquid crystal layer is formed between the two substrates. On the first substrate, pixel electrodes are formed on a matrix, and gate bus lines and source bus lines are formed. On the other hand, a black matrix formed of a transparent electrode and a resin is provided on the surface of the second substrate facing the first substrate. In the region where the black matrix and the transparent electrode overlap, the transparent electrode is formed between the black matrix and the second substrate. That is, a transparent electrode is formed between the black matrix and the second substrate. Therefore, in the region where the black matrix and the transparent electrode overlap, the black matrix is interposed between the transparent electrode and the first substrate. Therefore, in the manufacturing process of the liquid crystal display device, even if foreign matter is mixed into the region where the black matrix is formed in the liquid crystal layer, the configuration on the first substrate such as the source bus line and the transparent electrode are connected by the foreign matter. Can be prevented by the black matrix. At this time, the structure on the first substrate and the black matrix are connected by foreign matter, but the black matrix is formed by resin instead of metal, so even if the two substrates are connected by foreign matter, they are not electrically connected. Absent. As a result, an electrical short circuit (opposite leakage) between the two substrates can be prevented.

  In the liquid crystal display device according to the present invention, in the projected shape of the black matrix and the source bus line in the normal direction of the second substrate, the source bus line may be inside the black matrix. preferable.

  According to the above configuration, the black matrix faces the first substrate, not the transparent electrode, at a position facing the source bus line on the second substrate. Therefore, even if foreign matter is mixed in the liquid crystal layer on the source bus line in the manufacturing process and connected to the configuration on the second substrate, the configuration on the second substrate becomes a black matrix formed of resin. , They are not electrically connected and no opposing leakage occurs. Therefore, even if foreign matter is mixed in, the occurrence of the opposing leak through the source bus line can be suppressed.

  In the liquid crystal display device according to the present invention, in the projected shape of the black matrix and the gate bus line in the normal direction of the second substrate, the gate bus line may be inside the black matrix. preferable.

  According to the above configuration, the black matrix faces the first substrate instead of the transparent electrode at a position facing the gate bus line on the second substrate. Therefore, even if foreign matter is mixed in the liquid crystal layer on the gate bus line in the manufacturing process and connected to the configuration on the second substrate, the configuration on the second substrate becomes a black matrix made of resin. , They are not electrically connected and no opposing leakage occurs. Therefore, even if foreign matter is mixed in, the occurrence of the opposing leak through the gate bus line can be suppressed.

  In order to solve the above problem, a method for manufacturing a liquid crystal display device according to the present invention includes a first substrate and a second substrate facing each other with a liquid crystal layer interposed therebetween, and the first substrate of the second substrate. In the method of manufacturing a liquid crystal display device having a color filter layer, a black matrix, and a transparent electrode on the side facing the substrate, the step of forming the color filter layer on the second substrate and the color filter layer are formed The method includes a step of forming the transparent electrode on the second substrate and a step of forming the black matrix using a resin on the transparent electrode in this order.

  According to the above configuration, in the process of forming the color filter layer, the black matrix layer, and the transparent electrode layer on the second substrate, the color filter layer is first provided on the substrate, then the transparent electrode is provided, and finally the resin is provided. Is used to form a black matrix. Since the black matrix is formed after forming the transparent electrode, the black matrix is the outermost layer in the region where the transparent electrode and the black matrix overlap. That is, the transparent electrode is formed between the second substrate and the black matrix. Therefore, even if foreign matter is mixed in the region where the black matrix is formed in the liquid crystal display device in the manufacturing process of the liquid crystal display device, the configuration on the first substrate such as the source bus line and the transparent electrode are connected by the foreign matter. It is possible to manufacture a liquid crystal display device in which this is prevented by the black matrix. At this time, the structure on the first substrate and the black matrix are connected by foreign matter. However, since the black matrix is formed by resin instead of metal, even if the two substrates are connected by foreign matter, they are electrically connected. There is nothing. Therefore, it is possible to manufacture a liquid crystal display device in which the occurrence of an electrical short circuit (opposite leak) between the two substrates is suppressed.

  As described above, the liquid crystal display device according to the present invention includes the first substrate and the second substrate facing the first substrate with the liquid crystal layer interposed therebetween, and the black matrix and the transparent electrode are formed. In the second substrate, the black matrix is made of resin, and in the region where the black matrix and the transparent electrode overlap, the transparent electrode is formed between the black matrix and the second substrate. Therefore, even if foreign matter enters the liquid crystal layer, in the region where the black matrix is formed, the first substrate and the second substrate are not electrically connected by the foreign matter, and the occurrence of counter leakage is suppressed. .

  An embodiment of the liquid crystal display device according to the present invention will be described below with reference to FIGS.

[Liquid Crystal Display]
FIG. 1 is a cross-sectional view schematically showing a schematic configuration of a liquid crystal display device 1 having a nonSHA structure according to an embodiment of the present invention. FIG. 2 is a top view showing the configuration of the liquid crystal display device 1. 1 is a cross-sectional view taken along the line AA ′ in FIG.

  As shown in FIG. 1, the liquid crystal display device 1 includes an active matrix substrate 2, a counter substrate 4 provided so as to face the active matrix substrate 2, and a liquid crystal layer provided so as to be sandwiched between both the substrates 2 and 4. 6 is provided.

  The active matrix substrate 2 includes a glass substrate 21 (first substrate) that is a transparent insulating substrate, a plurality of gate bus lines 27 provided on the glass substrate 21 so as to extend in parallel with each other, and a parallel to the gate bus lines 27. A plurality of auxiliary capacitance lines 26 provided so as to extend, a plurality of source bus lines 23 provided so as to extend in parallel to each other in a direction orthogonal to the gate bus lines 27 and the auxiliary capacitance lines 26, and the gate bus lines 27 In addition, the semiconductor layer 20 provided at each intersection of the source bus lines 23 and the pixel electrode 25 provided in the display region surrounded by the pair of gate bus lines 27 and the source bus lines 23 corresponding to the semiconductor layers 20. And have.

  Further, a gate insulating film 22 is formed on the entire surface of the active matrix substrate 2 so as to cover the gate bus line 27 and the auxiliary capacitance line 26, and further, so as to cover the source bus line 23 and the semiconductor layer 20. An interlayer insulating film 24 is formed on the entire surface. The pixel electrode is formed on the interlayer insulating film 24.

  A semiconductor layer 20 is formed between the gate insulating film 22 and the interlayer insulating film 24. In this semiconductor layer, a channel region is formed in a corresponding portion of the gate electrode, and a source electrode 30 and a drain electrode 29 are formed outside the channel region.

  The liquid crystal layer 6 is formed from a liquid crystal material having electro-optical characteristics.

  The counter substrate 4 includes a glass substrate 41 (second substrate) which is a transparent insulating substrate, a color filter layer 42 formed on the glass substrate 41, and a counter electrode formed on the entire surface so as to cover the color filter layer 42. (Transparent electrode) 43 and a black matrix 44 formed on the counter electrode 43.

  The black matrix 44 is, for example, a combination of UV curable acrylic resin and coated carbon or RGB mixed color.

  As shown in FIG. 1, in the counter substrate 4 of the liquid crystal display device 1, the counter electrode 43 is provided between the glass substrate 41 and the black matrix 44 in a region where the black matrix 44 and the counter electrode 43 overlap. . That is, in the region where the black matrix 44 and the counter electrode 43 overlap, the black matrix 44 is opposed to the active matrix substrate 2.

  In the liquid crystal display device 1, an alignment film (not shown) is provided between the active matrix substrate 2 and the liquid crystal layer 6 and between the counter substrate 4 and the liquid crystal layer 6. The alignment film is a film for aligning liquid crystal molecules and may be subjected to an alignment process such as rubbing.

  As shown in FIG. 2, when viewed from the upper surface (direction orthogonal to the paper surface) of the liquid crystal display device 1, the source bus line 23, the gate bus line 27, and the black matrix 44 overlap each other, and the source bus line. 23 and the gate bus line 27 are located inside the black matrix 44. In FIG. 2, for the convenience of explanation, a part of the counter substrate 4 is shown. That is, in the projected shape of the black matrix 44, the source bus line 23 and the gate bus line 27 in the normal direction of the counter substrate 4, the source bus line 23 and the gate bus line 27 are located inside the black matrix 44. A black matrix 44, a source bus line 23, and a gate bus line 27 are provided. That is, the black matrix 44 is formed at a position facing the source bus line 23 and the gate bus line 27 in the counter substrate 4.

  Next, the operation of the liquid crystal display device 1 when a foreign substance is mixed in the liquid crystal display device 1 will be described with reference to FIGS.

  In the conventional liquid crystal display device 100 shown in FIG. 5, when a foreign substance 170 enters the source bus line 123, the foreign substance 170 comes into contact with the counter electrode (common electrode) 143 on the counter substrate 104. Will occur. As a result, the quality of the liquid crystal display device 100 is degraded.

  FIG. 3 is a cross-sectional view of the liquid crystal display device 1 showing a state in which foreign matter 70 is mixed in the liquid crystal layer 6 and on the source bus line 23 in the manufacturing process of the liquid crystal display device 1. As described above and shown in FIG. 3, in the liquid crystal display device 1 according to the present invention, the black matrix 44 is formed at a position facing the source bus line 23 in the counter substrate 4. In the region where the black matrix 44 is formed, the configuration on the counter substrate 4 facing the active matrix substrate 2 is not the counter electrode 43 but the black matrix 44. Therefore, even if the foreign substance 70 is mixed on the source bus line 23, the foreign substance 70 can be prevented from coming into contact with the counter electrode 43. As a result, the occurrence of counter leakage due to the electrical connection between the source bus line 23 and the counter electrode 43 can be suppressed.

  In the conventional liquid crystal display device 100, the black matrix is formed of a metal component such as titanium. Therefore, even if the black matrix 144 is formed between the counter electrode 143 and the active matrix substrate 102 as in the liquid crystal display device 1, if the foreign material 170 contacts the black matrix 144, the source bus line 123, the counter substrate 104, Will be electrically connected, and as a result, a counter leak will occur.

  In contrast, in the liquid crystal display device 1 according to the present invention, the black matrix 44 is formed of a resin such as a UV curable acrylic resin. Therefore, even if the foreign material 70 on the source bus line 23 is in contact with the black matrix 44, the source bus line 23 and the counter substrate 4 are not electrically connected. As a result, occurrence of counter leakage due to electrical connection between the source bus line 23 and the counter electrode 43 can be suppressed.

  In the counter substrate 4, a black matrix 44 is formed at a position facing the gate bus line 27, and the region where the black matrix 44 is formed is on the counter substrate 4 facing the active matrix substrate 2. The configuration is a black matrix 44 formed of resin instead of the counter electrode 43. Therefore, even when the foreign substance 70 is mixed on the gate bus line 27, the gate bus line 27 and the counter substrate 4 are electrically connected as in the case where the foreign substance 70 is mixed on the source bus line 23. There is no. As a result, it is possible to suppress the occurrence of counter leakage due to the electrical connection between the gate bus line 27 and the counter electrode 43.

  As described above, in the liquid crystal display device 1, the arrangement of the counter electrode 43 and the black matrix 44 on the counter substrate 4 is changed, and the black matrix 44 is formed of resin, thereby suppressing the occurrence of counter leakage. . Therefore, it is not necessary to provide a thick organic insulating layer such as an acrylic resin on the active matrix substrate 2.

[Manufacturing method of liquid crystal display device]
Next, a manufacturing method of the liquid crystal display device 1 according to the embodiment of the present invention will be described.

(Opposing substrate manufacturing process)
A color filter layer 42 is formed on the glass substrate 41 by patterning RGB (red, blue and green) colored layers corresponding to the pixels of the active matrix substrate 2 by a dry film method, a spin coating method, or the like.

  Next, a transparent electrode such as ITO is formed on the entire substrate on which the color filter layer 42 is formed by sputtering to form the counter electrode 43.

  Next, a black matrix 44 serving as a light shielding part is formed on the counter electrode 43 in a lattice pattern. This lattice pattern is patterned so as to overlap with the arrangement pattern of the gate bus lines 27 and the source bus lines 23 when the active matrix substrate 2 and the counter substrate 4 are overlapped.

  That is, the counter substrate manufacturing process includes a process of forming the color filter layer 42 on the glass substrate 41, a process of forming the counter electrode 43, and a process of forming the black matrix 44 on the counter electrode 43 using a resin. Are included in this order.

  Next, an alignment film made of a polyimide resin such as polyimide is formed by printing or coating. Alternatively, after a polyimide resin thin film is formed, an alignment treatment is performed on the surface by rubbing to form an alignment film.

  As described above, the counter substrate 4 constituting the present invention can be manufactured.

  In addition, as a formation method of the black matrix 44, the following several methods are possible.

  As a first method, first, a negative photosensitive black resin that is the basis of the black matrix 44 is formed on the glass substrate 41. Examples of the film forming method include application by a spin coater, a method in which a black resist previously formed in a film shape is attached to the glass substrate 41, and a method by cascade application. Next, the glass substrate 41 is irradiated with ultraviolet rays through a photomask having a predetermined black matrix pattern to cure the exposed portion of the black resin. Thereafter, the black matrix 44 is formed by removing the black resin in the unexposed area in the development process.

  As a second method for forming the black matrix 44, first, a negative photosensitive uncolored resin is formed on the glass substrate 41 in the same manner as the first method. Next, exposure and development are performed in the same manner as in the first method, and the original form of the black matrix 44 is patterned. Thereafter, the black matrix 44 is formed by coloring the pattern forming portion black. Examples of the coloring method include an electroless plating method and a staining method.

  As a third method for forming the black matrix 44, first, a black resin having developability is formed on the glass substrate 41 in the same manner as in the first method. Next, a positive photoresist is formed on the surface, and exposure and development are performed in the same manner as in the first method. In development, the photoresist and black resin in the exposed area are removed together. Then, the black resin is crosslinked and cured by heating, and then the unexposed resist is removed to form the black matrix 44.

(Active matrix substrate manufacturing process)
An aluminum (Al) film is formed on the glass substrate 21 using a sputtering apparatus. After the Al film is formed, a pattern is formed by an etching process such as a photolithography process and a dry etching to form the gate bus line 27, the gate electrode, and the auxiliary capacitance line 26 at the same time.

  In this embodiment, a glass substrate which is a transparent insulating substrate is used as the substrate. However, it may be a transparent substrate, for example, a plastic substrate.

Next, the gate insulating film 22 made of silicon nitride (SiN _x ) or the like is formed on the entire substrate on the gate bus line 27 by plasma CVD (Chemical Vapor Deposition).

  Next, in order to form an active element such as a thin film transistor (TFT), an active semiconductor layer is formed by plasma CVD. After forming the active semiconductor layer, an amorphous silicon layer such as n-type amorphous silicon is formed on the active semiconductor layer by plasma CVD. After the amorphous silicon layer is formed, the semiconductor layer 20 is formed by patterning using a photolithography technique.

  Next, an Al film is formed using a sputtering apparatus. Thereafter, a pattern is formed by a photolithography process and an etching process such as dry etching to form the source bus line 23, the source electrode 30 and the drain electrode 29.

  In this embodiment, Al is used to form the gate bus line 27, the gate electrode, the auxiliary capacitance line 26, the source bus line 23, the source electrode 30 and the drain electrode 29, but a desired bus line resistance can be obtained. For example, metals such as titanium (Ti) and chromium (Cr), and alloys thereof can be used. Further, a laminated film such as TiN (titanium nitride) / Al / Ti and Mo (molybdenum) / Al / Mo may be used.

Next, an insulating film made of silicon nitride (SiN _x ) or the like is formed on these by plasma CVD to form an interlayer insulating film 24 that is an inorganic insulating film. Thereafter, a contact hole 28 for electrically contacting the pixel electrode 25 and the drain electrode 29 formed thereon and a through hole for forming an auxiliary capacitor are formed in the interlayer insulating film 24 by a photolithography technique.

  Next, a transparent electrode such as ITO (Indium Tin Oxide) is formed on the entire substrate on the interlayer insulating film 24 by sputtering, and a pattern is formed by a photolithography process and an etching process to form a pixel electrode 25.

  Next, an alignment film made of a polyimide resin such as polyimide is formed by printing or coating. Alternatively, after a polyimide resin thin film is formed, an alignment treatment is performed on the surface by rubbing to form an alignment film.

  As described above, the active matrix substrate 2 constituting the present invention can be manufactured.

(Liquid crystal display manufacturing process)
Spacers such as plastic beads are dispersed on the active matrix substrate 2 and the counter substrate 4 so that the cell thickness of the panel can be maintained. Alternatively, column spacers are formed in advance on both substrates 2 and 4.

  Next, a thermosetting sealant made of a thermosetting resin such as an epoxy resin is drawn on both substrates 2 and 4 using a dispenser. The substrates 2 and 4 are bonded together, and the seal is cured by applying heat, and then a liquid crystal material is injected and sealed to form the liquid crystal layer 6. Alternatively, the liquid crystal layer 6 can be formed by bonding the substrates 2 and 4 together after the liquid crystal material is dropped and curing the seal.

  In this embodiment, a thermosetting material is used as the sealing material, but a UV (ultraviolet) curable material may be used. In this case, the seal can be cured by UV irradiation.

  As described above, the liquid crystal display device 1 of the present invention can be manufactured.

  In the manufacturing method according to the present invention, the order of the step of forming the counter electrode 43 and the step of forming the black matrix 44 is changed from the conventional method, and the black matrix 44 is formed of resin, so that the counter leak is reduced. The provision of the liquid crystal display device 1 in which generation is suppressed is realized. Therefore, it is possible to provide the liquid crystal display device 1 that can suppress the occurrence of counter leakage while omitting the step of providing a thick organic insulating layer such as an acrylic resin on the active matrix substrate 2.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims. That is, embodiments obtained by combining technical means appropriately modified within the scope of the claims are also included in the technical scope of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, the liquid crystal display device with which generation | occurrence | production of the opposing leak was suppressed by simple structure can be provided. Therefore, it is useful not only for small devices such as portable terminals and digital cameras, but also for large devices such as televisions.

It is a cross-sectional schematic diagram of the liquid crystal display device which concerns on embodiment of this invention. It is a top view of the liquid crystal display device concerning the embodiment of the present invention. It is a cross-sectional schematic diagram when the foreign material is mixed in the liquid crystal display device which concerns on embodiment of this invention. It is a cross-sectional schematic diagram of a conventional liquid crystal display device. It is a cross-sectional schematic diagram when the foreign material is mixed in the conventional liquid crystal display device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal display device 2 Active matrix substrate 4 Opposite substrate 6 Liquid crystal layer 20 Semiconductor layer 21 Glass substrate (1st substrate)
22 Gate insulating film 23 Source bus line 24 Interlayer insulating film 25 Pixel electrode 26 Auxiliary capacitance line 27 Gate bus line 28 Contact hole 29 Drain electrode 30 Source electrode 41 Glass substrate (second substrate)
42 Color filter layer 43 Counter electrode (transparent electrode)
44 Black matrix 70 Foreign matter

Claims (4)

A pixel substrate arranged in a matrix, and a first substrate on which gate bus lines and source bus lines are formed, and is opposed to the first substrate with a liquid crystal layer interposed therebetween, and is opposed to the first substrate. A liquid crystal display device comprising: a second substrate on which a black matrix and a transparent electrode are formed;
The black matrix is made of resin,
In the region where the black matrix and the transparent electrode overlap each other, the transparent electrode is formed between the black matrix and the second substrate.   2. The liquid crystal display according to claim 1, wherein in the projected shape of the black matrix and the source bus line in the normal direction of the second substrate, the source bus line is inside the black matrix. apparatus.   3. The liquid crystal display according to claim 2, wherein the gate bus line is located inside the black matrix in a projected shape of the black matrix and the gate bus line in the normal direction of the second substrate. apparatus. A liquid crystal display comprising a first substrate and a second substrate facing each other with a liquid crystal layer interposed therebetween, and having a color filter layer, a black matrix, and a transparent electrode on a side of the second substrate facing the first substrate In the device manufacturing method,
Forming the color filter layer on the second substrate;
Forming the transparent electrode on the second substrate on which the color filter layer is formed;
And a step of forming the black matrix on the transparent electrode using a resin in this order.

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