JP2004053815A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To keep a gap between substrates constant and to prevent moisture from permeating an interface of an interlayer insulation film by using a sealing member to seal in a liquid crystal between the substrates. <P>SOLUTION: In an active matrix substrate, a plurality of gate bus lines and a plurality of source bus lines 8 are disposed on a transparent substrate 22 so as to mutually perpendicularly intersect, switching elements are disposed adjacent to respective vertical intersections, an interlayer insulation film 50 is disposed so as to cover the gate bus lines, the source bus lines and the switching elements and further a plurality of pixel electrodes respectively connected to the respective switching elements are disposed in a matrix on the interlayer insulation film 50. A groove part 69 is disposed on a side edge part of the outside of the interlayer insulating film 50 so as to expose a base layer of the interlayer insulation film 50. The sealing member 28 to seal in the liquid crystal between a counter substrate and the active matrix substrate is disposed in the groove part 69 and on the interlayer insulation film 50 of both sides of the groove part 69. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an active matrix driving type liquid crystal display device, and more particularly, to a liquid crystal display device in which a switching element or the like provided on an active matrix substrate is covered with an interlayer insulating film and a pixel electrode is arranged on the interlayer insulating film. .
[0002]
[Prior art]
The liquid crystal display device performs display by selecting display pixels arranged in a matrix and writing image information into the pixels. With regard to the selection of display pixels, an active matrix driving method in which a switching element is provided for each pixel electrode is widely used. In particular, a TFT method using a thin film transistor as a switching element has characteristics such as high contrast and high-speed response. For some reason, it has become mainstream.
[0003]
In this active matrix drive type liquid crystal display device, when a signal voltage turned on and off by a switching element is applied to a pixel electrode, a voltage is applied between the pixel electrode and a counter electrode provided via a liquid crystal layer. Is applied, and an image is displayed by optically modulating the liquid crystal layer portion to which the voltage is applied.
[0004]
A conventional example of an active matrix drive type liquid crystal display device will be described with reference to FIGS. FIG. 7 is a plan view showing a schematic structure of an active matrix driving type liquid crystal display device, and FIG. 8 is a cross-sectional view taken along the line BB 'in FIG.
[0005]
In the liquid crystal display device of the active matrix drive system, one of a pair of substrates disposed with the liquid crystal layer 64 interposed therebetween is the active matrix substrate 22 and the other is the counter substrate 24. On the surface of the active matrix substrate 22, scanning wirings (gate bus lines, not shown) for operating the switching elements and signal wirings (source bus lines, not shown) for applying a signal voltage are provided. They are formed in a stacked state so as to be orthogonal to each other via a gate insulating film 38 of 100 to several μm, and pixel electrodes (not shown) are provided in the vicinity of their intersections. On the surface of the counter substrate 24, a counter electrode (not shown) is formed via a color filter layer 58 and the like.
[0006]
As shown in FIG. 8, the active matrix substrate 22 and the opposing substrate 24 are opposed to each other with a predetermined gap kept therebetween by a spacer 66, and an outer peripheral edge outside the display area also serves as an adhesive between the two substrates. Sealed by a seal member 28. Then, the liquid crystal layer 64 is sealed in a space surrounded by the seal member 28.
[0007]
The gate bus lines, source bus lines, and switching elements formed on the surface of the active matrix substrate 22 are covered with an interlayer insulating film 50, and a plurality of pixel electrodes (not shown) are provided on the interlayer insulating film 50. They are formed in a matrix.
[0008]
As described above, the pixel electrodes are arranged on the interlayer insulating film 50 having a thickness of several thousand to several μm so as to cover the gate bus lines, the source bus lines, and the switching elements. It is not formed in the same layer as the source bus line.
[0009]
In such a configuration, the pixel electrode can be arranged above the gate bus line and the source bus line so as to overlap with the gate bus line and the source bus line, so that the area of the pixel electrode can be increased. The aperture ratio can be increased. As a result, in the case of a transmissive liquid crystal display device, the transmittance can be greatly improved, and in the case of a reflective liquid crystal display device, the reflectivity can be greatly improved.
[0010]
In such a liquid crystal display device, in order to obtain a high transmittance in the visible light region and control the film thickness to be large, the interlayer insulating film 50 is formed of a transparent acrylic resin having photosensitivity. I have. In this case, the capacitance between each wiring such as the gate bus line and the source bus line and the pixel electrode can be reduced, and the crosstalk can be reduced.
[0011]
[Problems to be solved by the invention]
In an active matrix driving type liquid crystal display device having such an interlayer insulating film 50, as shown in FIG. 8, the interlayer insulating film 50 provided on the active matrix substrate 22 and made of acrylic resin or the like is extended to outside the display region. The active matrix substrate 22 and the counter substrate 24 are adhered by the seal member 28.
[0012]
As described above, the interlayer insulating film 50 on the active matrix substrate 22 is formed outside the display area where the liquid crystal 64 is sealed by being surrounded by the seal member 28 disposed between the active matrix substrate 22 and the counter substrate 24. Have been. As a result, the spacers 66 mixed in the seal member 28 and the spacers dispersed in the display area are formed on the same interlayer insulating film, and the interlayer insulating film 50 is formed with a constant thickness. This makes it possible to prevent a difference in the thickness of the liquid crystal layer 64 from occurring.
[0013]
On the other hand, when the interlayer insulating film 50 is limitedly provided inside the display region and does not exist below the seal member 28, the cell thickness in the display region may vary. That is, in the seal member 28 located outside the display area, the liquid crystal layer 64 has a constant thickness by the spacer 66 included in the seal member 28, whereas the interlayer insulating film formed in the display area has a constant thickness. And the liquid crystal layer 64 may not be formed to a certain thickness. As a result, if a difference occurs in the thickness of the liquid crystal layer 64 between the display area and the periphery thereof, display unevenness may occur at the peripheral edge of the display area and display quality may be degraded. In this case, the voltage applied to the liquid crystal layer 64 may deviate from the optimal state, and display reliability may be impaired.
[0014]
As shown in FIGS. 7 and 8, the thickness of the liquid crystal layer 64 can be made constant by providing the interlayer insulating film outside the display region. However, in such a configuration in which the sealing member 28 is provided on the interlayer insulating film 50, the interlayer insulating film 50 tends to have a hygroscopic property, so that the moisture permeability at the interface with the sealing member 28 becomes relatively high. However, there is a possibility that moisture permeates the liquid crystal layer 64. In particular, in an environment of high temperature, high humidity, or an environment where dew condensation is likely to occur, there is a high possibility that moisture will penetrate into the liquid crystal layer 64. , The charge retention rate is reduced, and the display quality is deteriorated.
[0015]
In order to solve this problem, as shown in FIG. 9, there has been proposed a configuration in which the seal member 28 is arranged so as to cover an end portion of the interlayer insulating film 50 located outside the display region. In such a configuration, the uniformity of the thickness of the liquid crystal layer is ensured by the region 67 in which the sealing member 28 is provided on the interlayer insulating film 50, and a sealing member having an appropriate thickness outside the interlayer insulating film 50. The presence of the region 68 provided with 28 suppresses the penetration of moisture from the interface between the seal member 28 and the interlayer insulating film 50 into the liquid crystal layer 64, thereby suppressing a reduction in display quality.
[0016]
However, for example, when the seal member 28 is provided by the screen printing method, the accuracy of the printing position is not always high, and therefore, the position of the seal member 28 may be shifted. As shown in FIG. 10, when the seal member 28 is shifted to the outside with respect to the interlayer insulating film 50, the area of the upper surface of the interlayer insulating film 50 on which the seal member 28 is provided becomes small and is included in the seal member 28. The spacers 66 cannot be disposed on the interlayer insulating film 50, and the thickness of the liquid crystal layer 64 may not be uniform. Conversely, when the seal member 28 is shifted inward with respect to the interlayer insulating film 50, the area 68 where the seal member 28 is provided becomes smaller outside the interlayer insulating film 50, and the seal member 28 and the interlayer insulating film 50 There is a possibility that moisture permeation from the interface with the liquid crystal layer 64 to the liquid crystal layer 64 cannot be suppressed.
[0017]
The present invention is intended to solve such a problem, and its object is to cover a switching element or the like on an active matrix substrate with an interlayer insulating film and to have a cross-sectional structure in which a pixel electrode is disposed thereon, Even if the position of the sealing member that seals the liquid crystal is shifted between the active matrix substrate and the counter substrate, the uniformity of the cell thickness is ensured and the penetration of moisture at the interface between the sealing member and the interlayer insulating film. An object of the present invention is to provide a liquid crystal display device capable of avoiding a decrease in display quality reliability.
[0018]
[Means for Solving the Problems]
The liquid crystal display device of the present invention is provided on a transparent substrate, in the vicinity of a plurality of gate bus lines, a plurality of source bus lines orthogonal to each gate bus line, and an intersection of each gate bus line and each source bus line. Is provided, an interlayer insulating film is provided so as to cover these gate bus lines, source bus lines and switching elements, and a plurality of pixel electrodes respectively connected to each switching element are provided on the interlayer insulating film. An active matrix substrate provided in a matrix, an opposing substrate disposed opposite to the active matrix substrate at a predetermined distance from the active matrix substrate, and a seal member sealed between the active matrix substrate and the opposing substrate. Liquid crystal display of active matrix driving type having liquid crystal layers arranged in a state In location, the seal member is, in the interlayer insulating film and is provided in the interlayer insulating film underlayer in a groove formed so as to be exposed and the groove on both sides of the interlayer insulating film.
[0019]
A spacer may be mixed in the seal member.
[0020]
The switching element may be a thin film transistor.
[0021]
The underlayer of the interlayer insulating film may be a gate insulating film or a channel protective layer of the thin film transistor, and the seal member may contact the gate insulating film or the channel protective layer.
[0022]
In the liquid crystal display device of the present invention, as described above, in the active matrix substrate in which the switching elements and the like are covered with the interlayer insulating film, the groove where the base layer is exposed is provided in the region of the interlayer insulating film where the seal member is provided. Since the seal member is provided in the groove and on both sides of the groove, even if the position of the seal member is shifted, the seal member in the groove reliably prevents moisture from permeating into the liquid crystal layer from the interlayer insulating film. In addition, since the spacer mixed in the seal member can be positioned on the interlayer insulating film, the distance from the counter substrate can be reliably maintained.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0024]
FIG. 1 is a schematic configuration diagram of an embodiment of a liquid crystal display device of the present invention, and FIG. 2 is an equivalent circuit diagram of the liquid crystal display device. This liquid crystal display device is a liquid crystal display device of an active matrix drive system, and has a pair of transparent substrates 22 and 24 arranged so as to face each other with a predetermined gap. One transparent substrate 22 constitutes an active matrix substrate. On the surface of the transparent substrate 22 constituting the active matrix substrate, gate bus lines 4 as scanning lines are provided in parallel along the row direction, and one end of each gate bus line 4 A scanning terminal 2 is provided. On the surface of the transparent substrate 22, source bus lines 8 as signal wiring are arranged in parallel along the column direction, and the signal terminals 6 are provided at one end of each of the source bus lines 8. Each is provided. Each gate bus line 4 and each source bus line 8 are orthogonal to each other, and a display pixel 10 (see FIG. 2) is provided near each intersection.
[0025]
The display pixel 10 includes a pixel electrode 12, a switching element 14 including a TFT (thin film transistor), an auxiliary capacitor 16, and the like. The switching element 14 is configured by, for example, a thin film transistor. Each storage capacitor 16 is connected to a storage capacitor bus line 20 parallel to the gate bus line 4, and the storage capacitor bus lines 20 are collectively grounded.
[0026]
As shown in FIG. 1, a counter electrode 18 and the like are provided on the surface of a transparent substrate 24 constituting the other counter substrate. Each pixel electrode 12 provided on the transparent substrate 22 of the active matrix substrate faces the counter electrode 18. A space between the transparent substrates 22 and 24 is sealed by a seal member 28 at a side edge portion outside the display area, and a liquid crystal is sealed in a space surrounded by the seal member 28 to form a liquid crystal layer 64. ing. In this case, the seal member 28 also functions as an adhesive for bonding the transparent substrates 22 and 24 to each other.
[0027]
In each of the display pixels 10, a liquid crystal layer 64 is provided between the pixel electrode 12 and the counter electrode 18. A gate signal is input to each gate bus line 4 and applied to the gate electrode of each switching element 14. Accordingly, the image signal input from each source bus line 8 is applied to the pixel electrode 12 via the source electrode and the drain electrode of the switching element 14.
[0028]
As described above, in the active matrix substrate of the liquid crystal display device, each display pixel 10 is provided in a rectangular region formed by intersecting a number of gate bus lines 4 and source bus lines 8. FIG. 3 is a plan view showing a configuration of one display pixel 10 provided on an active matrix substrate, and FIG. 4 is a cross-sectional view of the liquid crystal display device along AA ′ in FIG.
[0029]
The transparent substrate 22 provided on the active matrix substrate is insulative, and a plurality of gate bus lines 4 are provided on the transparent substrate 22 so as to be parallel to each other. On the transparent substrate 22, an auxiliary capacitance bus line 20 connected to the auxiliary capacitance 16 is provided.
[0030]
The gate electrode 36 of the switching element 14 in the display pixel 10 is provided in a branched manner on the gate bus line 4 near the intersection with the source bus line 8. On the transparent substrate 22, a gate insulating film 38 is provided over substantially the entire display region of the transparent substrate 22 so as to cover the gate bus line 4, the gate electrode 36, and the auxiliary capacitance bus line 20. A semiconductor layer 40 made of Si is provided on the gate electrode 36 via a gate insulating film 38 so as to cover the gate electrode 36. On each end of the semiconductor layer 40, ohmic contact layers 42 and 44 respectively formed of n + Si are laminated. On the gate insulating film 38, a source electrode 46 of the switching element 14 connected to one ohmic contact layer 42 is provided in a state of branching from the source bus line, and a switching electrode connected to the other ohmic contact layer 44 is provided. A drain electrode 48 of the element 14 is provided. The drain electrode 48 is in a state of being stacked on the auxiliary capacitance bus line 20 via the gate insulating film 38.
[0031]
The auxiliary capacitance 16 is formed by the storage capacitor bus line 20 and the drain electrode of the switching element 14 that are stacked on each other with the gate insulating film 38 interposed therebetween.
[0032]
On the transparent substrate 22, an interlayer insulating film 50 is provided over substantially the entire surface of the transparent substrate 22.
[0033]
On the interlayer insulating film 50, a rectangular pixel electrode 12 formed of a transparent conductive film is provided. The pixel electrodes 12 are provided between the gate bus lines 4 adjacent to each other and between the bus lines 8 of the sources adjacent to each other. And part of each source bus line 8.
[0034]
A contact hole 30 is provided in the interlayer insulating film 50 on the drain electrode 48 provided so as to be stacked on the auxiliary capacitance bus line 20 and below the pixel electrode 12. Through the drain electrode 48 of the switching element 14 is connected to the pixel electrode 12. The pixel electrode 12 is covered with an alignment film 54 provided on the interlayer insulating film 50.
[0035]
The transparent substrate 24 of the opposing substrate is also transparent insulative, and on the surface of the transparent substrate 24, a color filter layer 58, an opposing electrode 18 made of a transparent conductive film, and an alignment film 60 are sequentially laminated and provided. . The transparent substrate 24 of the opposing substrate is held at a predetermined interval from the transparent electrode 22 of the active matrix substrate by a spacer 62, and the peripheral portion of the transparent substrate 24 provided on the opposing substrate and the transparent electrode of the active matrix substrate. A seal member 28 is provided between the transparent substrate 22 and the substrate 22, and the transparent member 22 and 24 are adhered to each other by the seal member 28. Then, liquid crystal is sealed in a space between the transparent substrates 22 and 24 surrounded by the seal member 28 to form a liquid crystal layer 64.
[0036]
As described above, the auxiliary capacitance bus line 20 forms an auxiliary capacitance with the drain electrode 48 connected to the pixel electrode 12, and has the same potential as the counter electrode 18.
[0037]
In addition, a polarizing plate, an illuminating device, a retardation plate, and the like are appropriately provided on the outer surface of each of the transparent substrates 22 and 24, but they are not shown.
[0038]
FIG. 5 is a cross-sectional view of the seal member 28 and its peripheral portion in the liquid crystal display device, and corresponds to a cross section taken along line BB ′ of FIG.
[0039]
A seal member 28 is provided over substantially the entire periphery of the counter substrate 24, and the seal member 28 is bonded to an interlayer insulating film 50 on the transparent substrate 20 of the active matrix substrate. A display area is formed by a liquid crystal layer 64 provided in a space between the transparent substrates 22 and 24 surrounded by the seal member 28. The interlayer insulating film 50 provided on the transparent substrate 22 extends to the outside of the display region, and a groove 69 is provided in a region where the seal member 28 is provided in the extended portion. The groove 69 is formed over the entire length of the seal member 28 in a state where the gate insulating film 38 as a base layer of the interlayer insulating film 50 is exposed. The seal member 28 is provided inside the groove 69 of the interlayer insulating film 50 and over the interlayer insulating film 50 on both sides of the groove 69.
[0040]
With such a configuration, inside the groove 69, the seal member 28 is in direct contact with the gate insulating film 38 below the interlayer insulating film 50, and on both sides of the groove 69, the seal member 28 The contact regions 67 are in direct contact with the insulating film 50. Therefore, in the sealing member 28, a non-contact area 68 that does not contact the interlayer insulating film 50 is formed inside the groove 69 between the contact areas 67 on both sides of the groove 69, and the non-contact area 68 It is provided over the entire length of the member 28. Note that a spacer 66 is mixed in the seal member 28.
[0041]
When such a seal member 28 is provided on the interlayer insulating film 50 by screen printing, the seal member 28 cannot be formed on the interlayer insulating film 50 with high precision. For example, as shown in FIG. In some cases, the sealing member 28 may be shifted to the outside of the groove 69 provided in the interlayer insulating film. In this case as well, the groove 69 allows the sealing member 28 to be in a contact area where the sealing member 28 contacts the interlayer insulating film 50. A non-contact region 68 that does not contact the interlayer insulating film 50 is formed therebetween. In addition, since the non-contact region 68 is always formed with a constant width by the groove 69, the presence of the non-contact region surely suppresses the penetration of moisture into the liquid crystal layer 64.
[0042]
Even when the position of the seal member 28 is displaced in this manner, since the interlayer insulating film 50 exists outside the groove 69, the spacer 66 can be disposed on the interlayer insulating film 50, and the active matrix substrate and the The counter substrate can be securely bonded at a constant interval.
[0043]
Next, a method for manufacturing such a liquid crystal display device will be described.
[0044]
First, an alkali-free glass substrate is prepared as the transparent substrate 22 of the active matrix substrate, and a single-layer metal film of Ta, Ti, Al, Cr, or the like, or a multi-layer metal film thereof is formed on the substrate 22 by a sputtering method. The gate bus line 4 and the additional capacitance bus line 20 are formed by depositing and patterning in a predetermined shape. The gate bus line 4 and the additional capacitance bus line 20 are formed of, for example, a single layer of Ta.
[0045]
Next, a gate insulating film 38 is formed by depositing a silicon nitride film SiNx to a thickness of 3000 ° and patterning it into a predetermined shape by a plasma CVD method. Subsequently, the semiconductor layer 40 is formed by a plasma CVD method and patterned into a predetermined shape. As the semiconductor layer 40, for example, amorphous silicon (a-Si) is used, and its thickness is set to 1000 °.
[0046]
Once the semiconductor layer 40 is patterned, an amorphous silicon layer doped with phosphorus is deposited on each immediate portion of the semiconductor layer 40 to form ohmic contact layers 42 and 44. The ohmic contact layers 42 and 44 are provided to make ohmic contact between the semiconductor layer 40 and the source electrode 46 and the drain electrode 48 to be laminated thereafter. Each of the ohmic contact layers 42 and 44 is formed, for example, by forming an n + Si film to a thickness of 800 ° using a plasma CVD method and then patterning the film into a predetermined shape.
[0047]
Subsequently, a source bus line 8 and a source electrode 46 are formed by depositing a metal film of Ta, Ti, Al, Cr, or the like by a sputtering method and then patterning the film into a predetermined shape. The source bus line 8 and the source electrode 46 are formed of, for example, Ta.
[0048]
After that, a transparent conductive film is formed over substantially the entire surface of the transparent substrate 22, and then patterned into a predetermined shape to form the drain electrode. The drain electrode 48 is formed, for example, by a sputtering method using an indium oxide film doped with tin.
[0049]
Further, a photosensitive acrylic resin to be the interlayer insulating film 50 is formed on almost the entire surface of the transparent substrate 22 by spin coating to form an interlayer insulating film. After that, the acrylic resin of the interlayer insulating film 50 is exposed in a predetermined pattern shape, and is developed with an alkaline solution. As a result, only the exposed portions are etched by the alkaline solution to form contact holes 30 penetrating through interlayer insulating film 50. At this time, at the same time, a predetermined portion of the outer side edge portion of the interlayer insulating film 50 is exposed to a shape corresponding to the groove portion 69 and is developed to form the groove portion 69.
[0050]
After that, a number of pixel electrodes 18 are formed on the interlayer insulating film 50 in a matrix. The pixel electrode 18 is formed, for example, by forming a tin-doped indium oxide film by a sputtering method and patterning it into a predetermined shape.
[0051]
Thereafter, a solution containing a polyimide resin to be the alignment film 54 is applied to almost the entire surface of the transparent substrate 22 by offset printing. Also at this time, a printing plate is formed so that the alignment film 60 is not formed at a portion where the seal member 28 contacts. Since the polyimide resin used as the alignment film 54 has high hygroscopicity, it is for surely preventing moisture from penetrating into the inside of the liquid crystal layer 64 and for increasing the adhesive strength with the seal member 28. By forming the alignment film 54, an active matrix substrate is formed.
[0052]
On the other hand, a glass substrate is prepared as the transparent substrate 24 of the opposing substrate, and a color filter layer 58 in which respective color layers of red, blue, and green transmitted light are arranged in a stripe pattern is formed on the transparent substrate 24. I do. Between each color layer of the color filter layer 58 and at a portion corresponding to the switching element provided on the active matrix substrate, a light-shielding layer for preventing the switching element from malfunctioning due to external incident light is provided. . The color layer is formed, for example, by dispersing a pigment in an acrylic resin. The light-shielding layer is formed of Cr.
[0053]
Next, the transparent counter electrode 18 is formed on the color filter layer 58. The counter electrode 18 is formed, for example, by depositing indium doped with tin by a sputtering method. In this case, when depositing indium, a portion corresponding to the seal portion 28 is masked so that indium is not deposited on a portion in contact with the seal member 28. As a result, an indium oxide film having weak adhesion to the seal member 28 is not formed in a portion where the seal member 28 is provided.
[0054]
Thereafter, a solution containing a polyimide resin to be the alignment film 60 is applied to almost the entire surface of the transparent substrate 24 by offset printing. Also at this time, a printing plate is formed so that the alignment film 60 is not formed at a portion where the seal member 28 contacts. Since the polyimide resin used as the alignment film 60 has high hygroscopicity, it prevents moisture from penetrating into the liquid crystal layer 64 and increases the adhesive strength with the seal member 28. By forming the alignment film 60, a counter substrate is formed.
[0055]
The active matrix substrate and the opposing substrate thus formed are baked in an oven and subjected to rubbing treatment, and then the spacers 62 are scattered over the display area of the active matrix substrate. Thereafter, the active matrix substrate and the opposing substrate are bonded together by the seal member 28 into which the spacer 66 has been mixed. In this case, the seal member 28 is formed by screen printing so as to be injected into the groove 69 of the interlayer insulating film 50 provided on the active matrix substrate and to be located on the interlayer insulating film 50 on both sides of the groove 69. You.
[0056]
As the spacers 62 dispersed in the display area of the active matrix substrate, for example, polymer beads are used as the spacers 66 mixed with the seal member 28, and glass spacers are used, for example. The resin used is the resin used.
[0057]
Thereafter, a liquid crystal is injected between the active matrix substrate and the counter substrate by a vacuum injection method from an injection port provided in the seal member 28 to form a liquid crystal layer 64. Thereby, the liquid crystal display device of the present invention is manufactured.
[0058]
In the manufactured liquid crystal display device, since the sealing member 28 is formed so as to be located inside the groove 69 formed in the interlayer insulating film 50 and on the interlayer insulating film 50 on both sides of the groove 69, the groove is formed. The sealing member 28 in 69 can reliably prevent moisture from penetrating into the liquid crystal layer 64 via the interlayer insulating film 50. In addition, even if the spacer 66 mixed in the seal member 28 is arranged on the interlayer insulating film 50 outside the groove 69, the spacer 66 reliably keeps a constant distance from the counter substrate.
[0059]
Note that, in the above embodiment, a thin film transistor (TFT) in which a switching element has a gate electrode provided on a transparent substrate has been described. However, the present invention is not limited to such a configuration, and a semiconductor layer forming a channel region on a transparent substrate may be provided. The formed TFT may be used. In this case, the base layer of the interlayer insulating film becomes a channel protection layer covering the semiconductor layer forming the channel region, and the groove is formed so that the channel protection layer is exposed.
[0060]
【The invention's effect】
In the liquid crystal display device of the present invention, as described above, in the active matrix substrate in which the switching elements and the like are covered with the interlayer insulating film, the groove where the base layer is exposed is provided in the region of the interlayer insulating film where the seal member is provided. Since the seal member is provided in the groove and on both sides of the groove, even if the position of the seal member is shifted, the seal member in the groove reliably prevents moisture from permeating into the liquid crystal layer from the interlayer insulating film. In addition, since the spacer mixed in the seal member can be positioned on the interlayer insulating film, the distance from the counter substrate can be reliably maintained.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an entire structure of a liquid crystal display device of an active matrix drive system.
FIG. 2 is a circuit diagram showing a circuit configuration of an active matrix substrate of the liquid crystal display device.
FIG. 3 is a plan view showing a detailed planar structure of the active matrix substrate.
4 is a cross-sectional view showing a detailed cross-sectional structure of a liquid crystal display device in which the active matrix substrate is combined with a counter substrate, and corresponds to a cross section taken along line AA ′ in FIG.
FIG. 5 is a cross-sectional view showing an important substrate bonding structure in the liquid crystal display device, and corresponds to a cross section taken along line BB 'in FIG.
FIG. 6 is a cross-sectional view for explaining the operation of the substrate bonding structure, and corresponds to a cross section taken along line BB 'in FIG.
FIG. 7 is a plan view showing a schematic structure of a liquid crystal display device of an active matrix drive system.
8 is a cross-sectional view showing a conventional substrate bonding structure, and corresponds to a cross section taken along line BB 'in FIG.
FIG. 9 is a cross-sectional view showing another conventional substrate bonding structure, and corresponds to a cross section taken along line BB 'in FIG.
FIG. 10 is a cross-sectional view for explaining a problem in the substrate bonding structure, and corresponds to a cross section taken along line BB ′ in FIG.
[Explanation of symbols]
2 Scan terminal
4 Gate bus line
6 signal terminals
8 Source bus line
10 display pixels
12 Pixel electrode
14 Switching element
16 Auxiliary capacity
18 Counter electrode
20 auxiliary capacity bus line
22 Transparent substrate
24 Transparent substrate
28 Sealing member
30 contact holes
36 Gate electrode
38 Gate insulating film
46 source electrode
48 drain electrode
50 interlayer insulating film
54 Alignment film
60 Alignment film
58 color filter layer
62 spacer
66 Spacer
64 liquid crystal layer
67 Contact area
68 Non-contact area
69 Groove

Claims (4)

On a transparent substrate, a plurality of gate bus lines, a plurality of source bus lines orthogonal to each gate bus line, and a switching element provided near an intersection of each gate bus line and each source bus line are provided. An active matrix in which an interlayer insulating film is provided so as to cover these gate bus lines, source bus lines and switching elements, and a plurality of pixel electrodes respectively connected to the switching elements are provided in a matrix on the interlayer insulating film. Board and
A counter substrate that is disposed to face the active matrix substrate while maintaining a predetermined interval,
In an active matrix driving type liquid crystal display device having a liquid crystal layer disposed in a sealed state by a seal member between the active matrix substrate and the counter substrate,
The liquid crystal display device, wherein the seal member is provided in a groove formed in the interlayer insulating film such that a base layer of the interlayer insulating film is exposed, and on the interlayer insulating film on both sides of the groove. . The liquid crystal display device according to claim 1, wherein a spacer is mixed in the seal member. The liquid crystal display device according to claim 1, wherein the switching element is a thin film transistor. 4. The liquid crystal display device according to claim 3, wherein the underlayer of the interlayer insulating film is a gate insulating film or a channel protective layer of the thin film transistor, and the seal member is in contact with the gate insulating film or the channel protective layer.

Images