JP2001222028A - Liquid crystal device and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal device having a structure capable of reducing a sticking deviation between a pair of substrates to the utmost. SOLUTION: A recessed part 20 formed at a part of a pixel contact hole 12 electrically connecting a drain electrode 11 and a pixel electrode 1 of a TFT on a TFT array substrate 7 and a projecting part 27 for preventing the sticking deviation between a pair of substrates, formed on a counter substrate 15, are engaged with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal device and an electronic apparatus, and more particularly to a structure of a substrate suitable for use in preventing a displacement of a pair of substrates constituting a liquid crystal device.

[0002]

2. Description of the Related Art FIG. 8 shows an example of a conventional liquid crystal display device. As shown in FIG.
A plurality of data lines and scanning lines 101 are formed in a lattice pattern, a pixel electrode, and a thin film transistor (hereinafter, referred to as a TFT) driving the pixel electrode.
The device substrate 102 (TFT array substrate in this example) on which switching elements and the like formed of a matrix are arranged in a matrix, and a counter substrate 104 (color filter substrate) on which a counter electrode 103, a color filter and the like are disposed. They are arranged at predetermined intervals. The element substrate 102 and the opposing substrate 104 are adhered to each other at a fixed interval by a sealing material 106 mixed with a cylindrical or spherical spacer 105 made of, for example, glass fiber so that the electrode forming surfaces face each other. , Two substrates 102 and 10
Liquid crystal 107 is sealed in the gap between the four. The polarizer 10 is provided on the outer surface of the element substrate 102 and the counter substrate 104.
8, 109 are respectively attached.

Although not shown, the element substrate 102
A data line driving IC for supplying a data signal to each data line is mounted on a terminal portion protruding from the upper counter substrate 104, and a scanning line driving IC for supplying a scanning signal to each scanning line 101 is mounted. Have been.

Further, in the case of this example, a backlight unit 110 is provided on the lower surface side of the element substrate 102 via a cushioning material 111 such as silicon rubber. The backlight unit 110 includes a linear fluorescent tube 1 for irradiating light.
12 and the light guide plate 1
13 and a diffuser 115 for uniformly diffusing the light guided to the light guide 113 to the liquid crystal panel 100.
And a reflector 116 that reflects light emitted from the light guide plate 113 in the opposite direction to the liquid crystal panel 100 toward the liquid crystal panel 100.

When manufacturing this type of liquid crystal display device,
As is called so-called multi-paneling, etc., a pattern constituting a plurality of liquid crystal panels is collectively formed on each substrate, and after two substrates are bonded together, this is cut, and each liquid crystal panel unit is cut. It is common to adopt a method of dividing.

More specifically, with reference to FIG. 9 showing an outline of a process of assembling a liquid crystal panel, as shown in FIG. 9A, after forming an element substrate 120 and a counter substrate 121, for example, A spacer 122 for keeping a constant distance between the two substrates is sprayed on the electrode forming surface of the substrate 120, and a sealing material 123 for sealing liquid crystal is screen-printed on the electrode forming surface of the counter substrate 121. Is formed.

[0007] Next, as shown in FIG.
The substrates 120 and 121 are attached to each other, and as shown in FIG. 9 (3), the panel is divided using a diamond glass scriber, a break machine, or the like.
24.

[0009] Thereafter, as shown in FIG. 9 (4), the sealing material 1 of each liquid crystal panel 124 is
The liquid crystal 126 is injected into the gap between the two substrates from the liquid crystal injection port 123a, which is the opening of 23.

Thereafter, as shown in FIG. 9 (5), the liquid crystal injection port 123a is sealed with a sealing material 127, and a polarizing plate is adhered on both sides to complete the liquid crystal panel 124. Finally, a backlight unit, various driving substrates, and the like are mounted on the liquid crystal panel 124 and stored in a case, thereby completing a liquid crystal display device.

[0010]

In the above-described manufacturing process of the liquid crystal display device, the steps of applying a sealing material, distributing spacers, bonding, dividing the panel, etc. are steps for producing a so-called empty panel before liquid crystal injection. These steps are relatively difficult to stabilize.

For example, in the step of bonding the element substrate and the counter substrate, the alignment marks of both substrates are aligned with a micron accuracy by an automatic alignment device using image processing, and then the sealing material is hot-pressed to the diameter of the scatter spacer. A method of curing the sealing material while maintaining a predetermined cell gap is adopted. This process has an element of causing a shift due to the accuracy of the so-called bonding technique, which includes the patterning error at the time of manufacture of each substrate and the alignment accuracy. Therefore, the superposition of the element substrate and the counter substrate is designed with a margin of, for example, 5 to 10 μm. Reducing this margin leads to a higher aperture ratio of the liquid crystal panel, and is an important issue for improving brightness.

However, in each bonding process such as alignment, pressing, sealing material curing, etc., it is very difficult to suppress the bonding deviation while making the cell gap uniform, and it is inevitable that a certain degree of deviation occurs. Was. In addition, in order to minimize the displacement, a method such as curing the sealing material while tightening the two substrates using a pressing jig is sometimes used. And there was a problem in terms of productivity.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and provides a liquid crystal device having a structure capable of minimizing a bonding displacement between a pair of substrates, and an electronic apparatus using the same. The purpose is to do.

[0014]

In order to achieve the above object, a liquid crystal device according to the present invention comprises a pair of substrates opposed to each other, wherein a liquid crystal is sandwiched between the pair of substrates. A plurality of scanning lines and a plurality of data lines provided crossing each other, a plurality of pixel electrodes and a plurality of TFTs arranged in a matrix corresponding to the intersection of the scanning lines and the data lines; A liquid crystal device having:
The gap between the concave portion formed in the pixel contact hole portion for electrically connecting the drain electrode of the TFT and the pixel electrode on the one substrate and the pair of substrates provided on the other substrate is determined. It is characterized in that a projection for preventing the projection is fitted.

One of the substrates constituting the liquid crystal device, that is, the pixel contact hole portion of the element substrate, is necessarily concave because the step of the laminated film constituting the element substrate is reduced. Therefore, according to the present invention, if the other substrate, that is, a convex portion that can be fitted into the concave portion is provided in advance at a position corresponding to the pixel contact hole portion on the counter substrate, and these are fitted, Positioning of the two substrates can be performed. When the two substrates are superimposed on each other, the substrates are difficult to move, so that a displacement in bonding that occurs in an assembly process can be prevented. That is, since the projections and depressions in the present invention also serve as conventional alignment marks, it is possible to rationally position the two substrates, and to prevent misalignment.

[0016] The protruding portion may be a part of the other substrate.
It is preferable to form from a layer or a plurality of layers of film material.
According to this configuration, it is not necessary to prepare a member separate from the substrate when forming the convex portion on the other substrate, and the component cost does not increase. Further, since the projection is formed only by the step made of the film material constituting the counter substrate, the projection can be sufficiently formed by a normal manufacturing process.

The projections can be formed from a resin material film such as an acrylic film or a polyimide film. Alternatively, it may be formed from an inorganic material film such as a silicon oxide film or a silicon nitride film.

An electronic apparatus according to the present invention includes the liquid crystal device according to the present invention. According to the present invention, it is possible to realize an electronic device having a display unit with high display quality by including the liquid crystal device of the present invention.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is an equivalent circuit of various elements, wiring, and the like in a plurality of pixels forming an image display area of the liquid crystal device of the present embodiment. FIG. 2 is a plan view of a plurality of adjacent pixel groups on a TFT array substrate on which data lines, scanning lines, pixel electrodes, and the like are formed.
FIG. 3 is a sectional view taken along line AA ′ of FIG. 2. In FIG. 3, the scale of each layer and each member is different so that each layer and each member have a size recognizable in the drawing.

[Structure of Main Parts of Liquid Crystal Device] As shown in FIG. 1, in the liquid crystal device of the present embodiment, a plurality of pixels formed in a matrix forming an image display area are composed of a pixel electrode 1 and the pixel. A plurality of TFTs 2 for controlling the electrodes 1 are formed in a matrix, and a data line 3 for supplying an image signal is electrically connected to a source region of the TFT 2. Image signals S1 and S written to data line 3
,..., Sn may be supplied line-sequentially in this order, or may be supplied to a plurality of adjacent data lines 3 for each group. Further, the scanning line 4 is electrically connected to the gate electrode of the TFT 2, and the scanning signal G is pulsed to the scanning line 4 at a predetermined timing.
, Gm are applied line-sequentially in this order. The pixel electrode 1 is electrically connected to the drain region of the TFT 2. By closing the switch of the TFT 2 serving as a switching element for a certain period, the image signals S 1, S 2,
..., Sn is written at a predetermined timing.

The image signals S1, S2,..., Sn of a predetermined level written in the liquid crystal via the pixel electrode 1 are exchanged with a counter electrode (described later) formed on a counter substrate (described later) for a certain period. Will be retained. Here, in order to prevent the held image signal from leaking, a storage capacitor 5 is added in parallel with a liquid crystal capacitor formed between the pixel electrode 1 and the counter electrode. For example, the voltage of the pixel electrode 1 is held by the storage capacitor 5 for a time that is three digits longer than the time when the source voltage is applied. Thereby, the holding characteristics are further improved, and a liquid crystal device having a high contrast ratio can be realized. As will be described later,
In the present embodiment, as a method of forming the storage capacitor 5,
A capacitance line 6 which is a wiring for forming a capacitance with the semiconductor layer is provided. Also, instead of providing the capacitance line 6,
A capacitor may be formed between the pixel electrode 1 and the preceding scanning line 4.

As shown in FIG. 2, indium tin oxide (Indium Tin Oxi) is provided on the TFT array substrate 7 of the liquid crystal device.
de, hereinafter abbreviated as ITO), a plurality of pixel electrodes 1 (contours are indicated by broken lines) made of a transparent conductive film are arranged in a matrix, and along the sides of the pixel electrodes 1 extending in the vertical direction on the paper. A data line 3 (a contour is shown by a two-dot chain line) is provided, and a scanning line 4 and a capacitor line 6 (both are shown by a solid line) are provided along a side extending in the lateral direction of the paper. In the present embodiment, the semiconductor layer 8 made of a polysilicon film (the outline is shown by a dashed line) is formed in a U-shape near the intersection of the data line and the scanning line, and one end of the U-shaped portion 8a is formed. Extend in the direction of the adjacent data line 3 (rightward on the paper) and in the direction along the data line 3 (upward on the paper). Contact holes 9 and 10 are formed at both ends of the U-shaped portion 8a of the semiconductor layer 8, and one contact hole 9 becomes a source contact hole for electrically connecting the data line 3 and the source region of the semiconductor layer 8, The other contact hole 10 is a drain contact hole that electrically connects the drain electrode 11 (the outline is indicated by a two-dot chain line) and the drain region of the semiconductor layer 8. A pixel contact hole 12 for electrically connecting the drain electrode 11 and the pixel electrode 1 is formed at an end of the drain electrode 11 opposite to the side where the drain contact hole 10 is provided.

The TFT 2 in this embodiment crosses the scanning line 4 at the U-shaped portion 8a of the semiconductor layer 8, and the semiconductor layer 8 and the scanning line 4 cross twice.
A TFT having two gates on one semiconductor layer, that is, a so-called dual gate TFT is formed. Also, the capacitance line 6
Extends along the scanning line 4 so as to penetrate the pixels arranged in the horizontal direction on the paper surface, and a branched part 6 a extends in the vertical direction on the paper surface along the data line 3. Therefore, both data lines 3
The storage capacitor 5 is formed by the semiconductor layer 8 and the capacitor line 6 extending long along the line.

As shown in FIG. 3, the liquid crystal device according to the present embodiment has a pair of transparent substrates 13 and 14, one of which is a TFT array substrate 7 and the other is disposed to face the TFT array substrate 7. And a counter substrate 15 serving as the other substrate. A liquid crystal 16 is sandwiched between the substrates 7 and 15. The TFT array substrate 7 and the counter substrate 15 are made of, for example, a glass substrate or a quartz substrate. FIG. 3 is a diagram showing a state in which the formation portion of the pixel contact hole 12 is cut, and the cross-sectional structure of the TFT portion is not different from that of the conventional structure, and is not shown. In FIG. 3, the scales such as the film thickness and the lateral dimension are different for each layer and each member in order to make the drawing easy to see.

In the portion of the pixel contact hole 2,
A semiconductor layer 8 made of, for example, a polysilicon film having a thickness of about 50 nm is provided on the TFT array substrate 7, and a gate insulating film 17 having a thickness of about 100 to 150 nm is formed on the entire surface so as to cover the semiconductor layer 8. ing. A scanning line 4 made of a metal such as tantalum is formed on the gate insulating film 17, and a capacitance line 6 made of a metal of the same layer as the scanning line 4 is formed.
A first interlayer insulating film 18 is formed on the entire surface so as to cover. A drain electrode 11 made of a metal such as aluminum is formed on the first interlayer insulating film 18. Although not shown in FIG. 3, the data line 3 made of metal of the same layer as the drain electrode 11 is formed on the first interlayer insulating film 18 so as to cover the drain electrode 11 and the data line 3. The second interlayer insulating film 19 is formed.
Then, the drain electrode 1 penetrates through the second interlayer insulating film 19.
A pixel contact hole 12 reaching one surface is provided;
The pixel electrode 1 made of a transparent conductive film such as ITO is provided at the pixel contact hole 12 and electrically connected to the drain electrode 11. Here, the second interlayer insulating film 19
Is used as a flattening film. For example, an acrylic film, which is a kind of resin film having high flatness, is formed to a thickness of about 2 μm. Therefore, the pixel contact hole 12
Since the second interlayer insulating film 19 has an opening in the portion, a relatively large step is formed, and the concave portion 20 having a depth of about 1.5 μm is formed.
Is formed.

On the other hand, a light-shielding film 21 (black matrix) made of, for example, a metal film of chromium or the like, a resin black resist or the like is formed on the counter substrate 15 in a lattice pattern, and R (red) is provided between the light-shielding films 21. , G (green) and B (blue) are formed. Overcoat film 2 covering color filter layer 22
On the overcoat film 23, a counter electrode 24 made of a transparent conductive film such as ITO is formed, like the pixel electrode 1.
Are formed on the entire surface. The TFT array substrate 7,
On both surfaces of the opposing substrate 15 that are in contact with the liquid crystal 16, alignment films 25 and 26 made of polyimide or the like are provided.

In a conventional general liquid crystal device, even if a concave portion is formed in a pixel contact hole forming position on a TFT array substrate, the corresponding position on the counter substrate side is merely a flat surface. is there. On the other hand, in the case of the liquid crystal device of the present embodiment, the concave portion 20 formed on the TFT array substrate 7 at the position where the pixel contact hole 12 is formed is fitted into the concave portion 20 on the counter substrate 15 side. A convex portion 27 having a shape and size that can be used is provided. That is, similar to the second interlayer insulating film 19 of the TFT array substrate 7,
The overcoat film 23 of the counter substrate 15 is formed of an acrylic film, and the overcoat film 23 projects at a position corresponding to the position where the pixel contact hole 12 is formed to form a convex portion 27, on which a counter electrode is formed. 24, alignment film 26
Are sequentially formed. The planar shape of the projection 27 is a slightly smaller planar shape of the pixel contact hole 12. The height of the projection 27 is, for example, about 3.5 μm, and the tip of the projection 27 is fitted into the recess 20 having a depth of 1.5 μm. The distance G (cell gap) between the substrates 15 is 2 μm
It has become about.

According to the liquid crystal device of the present embodiment, the TFT
By fitting a convex portion 27 formed at a position corresponding to the pixel contact hole 12 on the opposing substrate 15 into a concave portion 20 formed in a region where the pixel contact hole 12 is formed on the array substrate 7, the two substrates 7, 15 alignments can be performed. When the two substrates 7 and 15 are superimposed on each other, these substrates are difficult to move, so that the displacement of bonding that occurs in the conventional assembly process can be reduced.

In the case of this embodiment, the counter substrate 15
Since the upper convex portion 27 is formed by the overcoat film 23 of the color filter layer 22, there is no need to prepare a separate member from the substrate when forming the convex portion 27, and the component cost does not increase. In particular, there is no need to change the manufacturing process.

[Overall Configuration of Liquid Crystal Device] Next, the liquid crystal device 4
0 will be described with reference to FIG. In FIG. 4, a sealing material 28 is provided on the TFT array substrate 7 along the edge thereof, and a light shielding film 29 as a frame is provided in parallel with the inside of the sealing material 28. A data line driving circuit 30 and an external circuit connection terminal 31 are provided along one side of the TFT array substrate 7 in a region outside the sealing material 28, and a scanning line driving circuit 32 is provided on two sides adjacent to this one side. It is provided along. If the delay of the scanning signal supplied to the scanning line 4 does not matter, it goes without saying that the scanning line driving circuit 32 may be provided on only one side. Also,
The data line driving circuits 30 may be arranged on both sides along the side of the image display area. For example, the odd-numbered data lines 3 supply an image signal from a data line driving circuit disposed along one side of the image display area, and the even-numbered data lines 3 are provided on the opposite side of the image display area. The image signal may be supplied from a data line driving circuit disposed along the line. When the data lines 3 are driven in a comb-tooth shape in this manner, the area occupied by the data line driving circuit can be expanded, so that a complicated circuit can be formed. further,
On one remaining side of the TFT array substrate 7, a plurality of wirings 33 for connecting between the scanning line driving circuits 32 provided on both sides of the image display area are provided. At least one corner of the counter substrate 15 is provided with a conductive material 34 for establishing electrical connection between the TFT array substrate 7 and the counter substrate 15. The opposite substrate 15 having substantially the same contour as the seal member 28 is fixed to the TFT array substrate 7 by the seal member 28.

[Electronic Equipment] Hereinafter, specific examples of electronic equipment having the liquid crystal device of the present invention will be described. FIG. 5 is a perspective view showing an example of a mobile phone. In FIG. 5, reference numeral 1000 denotes a mobile phone main body, and reference numeral 1001 denotes a liquid crystal display unit using the above-described liquid crystal device. FIG. 6 is a perspective view showing an example of a wristwatch-type electronic device. In FIG. 6, reference numeral 1100 denotes a watch body, and reference numeral 1101 denotes a liquid crystal display unit using the above-described liquid crystal device. FIG.
1 is a perspective view showing an example of a portable information processing device such as a word processor or a personal computer. In FIG.
Denotes an information processing device, reference numeral 1202 denotes an input unit such as a keyboard, reference numeral 1204 denotes an information processing device main body, and reference numeral 1206 denotes a liquid crystal display unit using the above-described liquid crystal device. FIG.
Since the electronic device shown in FIG. 7 includes a liquid crystal display portion using the above-described liquid crystal device, an electronic device with excellent display quality can be realized.

The technical scope of the present invention is not limited to the above-described embodiment, and various changes can be made without departing from the spirit of the present invention. For example, in the above embodiment, the convex portion on the counter substrate side corresponding to the concave portion of the pixel contact hole portion was formed with an overcoat film of a color filter made of an acrylic film.
The color filter layers of R, G and B may be formed by overlapping. Further, not only a resin material film such as an acrylic film but also an inorganic material film such as a silicon oxide film and a silicon nitride film can be used. Furthermore, if the manufacturing process is allowed to be complicated, it can be formed of a completely different film.

[0033]

As described in detail above, according to the present invention, by fitting a convex portion on the other substrate into a concave portion in the pixel contact hole forming region of one substrate,
Positioning of two substrates can be performed, and when the two substrates are superimposed on each other, these substrates are difficult to move, so that the bonding displacement that occurs in the conventional assembly process can be reduced.

[Brief description of the drawings]

FIG. 1 is an equivalent circuit diagram of a liquid crystal device according to an embodiment of the present invention.

FIG. 2 is an enlarged plan view showing a pixel configuration of the liquid crystal device.

FIG. 3 is a sectional view taken along the line A-A 'of FIG.

FIG. 4 is a plan view showing the overall configuration of the liquid crystal device.

FIG. 5 is a perspective view illustrating an example of an electronic apparatus including the liquid crystal device of the present invention.

FIG. 6 is a perspective view illustrating another example of the electronic apparatus.

FIG. 7 is a perspective view showing still another example of the electronic apparatus.

FIG. 8 is a cross-sectional view illustrating an example of a conventional liquid crystal device.

FIG. 9 is a diagram for explaining an example of a liquid crystal panel assembling process.

[Explanation of symbols]

 Reference Signs List 1 pixel electrode 2 TFT (thin film transistor) 3 data line 4 scanning line 5 storage capacitance 6 capacitance line 7 TFT array substrate 8 semiconductor layer 11 drain electrode 12 pixel contact hole 15 facing substrate 16 liquid crystal 20 concave portion 27 convex portion 40 liquid crystal device

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Ken Kubota 2-3-2 Marunouchi, Chiyoda-ku, Tokyo F-term (reference) 2H090 HA03 HB03X HB07X HB08X HD01 JC03 JC07 JC14 JC17 JD15 LA02 LA04 2H092 JA25 JA29 JA33 JA35 JA46 JB13 JB42 JB57 JB63 JB68 KA04 KA07 KA16 KA18 KB14 MA12 MA27 NA25 NA29 PA03 PA08

Claims (5)

[Claims] 1. A liquid crystal is sandwiched between a pair of substrates facing each other, and a plurality of scanning lines and a plurality of data lines provided on one of the pair of substrates so as to intersect with each other. A liquid crystal device having a plurality of pixel electrodes and a plurality of thin film transistors arranged in a matrix corresponding to intersections of the scanning lines and the data lines, and a drain electrode of the thin film transistors on the one substrate; A concave portion formed in a pixel contact hole portion for electrically connecting the pixel electrode and a convex portion for preventing the pair of substrates provided on the other substrate from being bonded to each other are fitted. A liquid crystal device. 2. The method according to claim 1, wherein the convex portion constitutes the other substrate.
2. The liquid crystal device according to claim 1, wherein the liquid crystal device is formed of a layer or a plurality of layers of a film material. 3. The liquid crystal device according to claim 2, wherein the protrusion is formed of a resin material film. 4. The liquid crystal device according to claim 2, wherein the projection is made of an inorganic material film. 5. An electronic apparatus comprising the liquid crystal device according to claim 1.