JPH10161572A - Picture display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a picture display device allowing its large scale screen to be manufactured with a good yield. SOLUTION: A liquid crystal display 100 is composed by combining four sheets of driving substrates 101-104. Each of the driving substrates 101-104 is provided with a liquid crystal display 107 containing many TFTs arranged in a matrix form, a vertical driving circuit 108 to drive the liquid crystal display 107, and a peripheral driving circuit 110 containing a horizontal driving circuit 109. Each of the driving substrates 101-104 has an independent display function, and forms a large-scale display screen as a whole. Each of the driving substrates 101-104 has joint areas 111, 112 on the sides facing to the other driving substrates respectively and they are connected with each other with a connection material having a same refraction index. It is possible to compose a large-scale liquid crystal display 100 without defects as a whole by selecting and combining only satisfactory driving substrates without defects.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device such as a liquid crystal display device, and more particularly, to an image display device provided with a drive board on which a display section and a peripheral drive circuit for driving the display section are formed. About.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for higher performance of liquid crystal display devices, improvements for higher definition and higher brightness have been made, and developments for practical use of large screens have been actively conducted. It has been done. This liquid crystal display device generally has
It has a structure in which an electro-optical material (liquid crystal) layer is sandwiched between two transparent substrates (panels) called a driving substrate and a counter substrate, respectively. The driving substrate is formed of, for example, a glass plate. On the driving substrate, transparent pixel electrodes and TFTs (Thin Film Transistors) serving as switching elements for driving the pixel electrodes are provided.
Are integrated. As these TFTs, a so-called polycrystalline silicon T having an active layer thin film made of polycrystalline silicon is used.
When FT is used, in addition to a switching element for driving a pixel electrode, a peripheral driving circuit such as a shift register for transferring a selection pulse to the switching element can be formed on the same substrate. Become.

FIG. 15 shows a plan view of the liquid crystal display device 10 having a large screen with an angle of view of about 14 inches, on the drive substrate 11 side. The driving substrate 11 is formed of a single glass substrate. On the driving substrate 11, a liquid crystal display unit 12 including a large number of TFTs arranged in a matrix, and a vertical driving circuit for driving the liquid crystal display unit 12 14 and a peripheral drive circuit 16 including a horizontal drive circuit 15.

[0004]

By the way, although the development of the liquid crystal display device as described above has been made to increase the size, conventionally, there has been a problem that the yield of the product decreases as the size of the liquid crystal display device increases.

That is, generally, an IC (Integrated Cir
cuit), by forming many chips on one wafer (substrate), it is possible to select defective chips (defective products) and non-defective chips (non-defective products). Only good products can be shipped as products. On the other hand, as shown in FIG. 15, in order to increase the size of the liquid crystal display device 10,
If a large glass substrate is used as it is, pattern defects are likely to occur due to dust generated in a photolithography process or a CVD (Chemical Vapor Deposition) process. Therefore, for example, as shown in FIG. 15, even if only one pattern defect 13 is generated, the substrate is regarded as a defective product, and a long time is required for the subsequent defect correction and defect detection steps, and the manufacturing cost increases. There was a problem of doing. The incidence of pattern defects due to such dust increases as the area of the substrate increases.

For example, as shown as a liquid crystal display device 20 in FIG.
For example, four small drive boards 21 on which a peripheral drive circuit 16 including a vertical drive circuit 14 and a horizontal drive circuit 15 for driving the liquid crystal display unit 12 are formed are combined, and the four liquid crystal display units 12 A method of forming a large screen is also conceivable. However, even with such a configuration, for example, when a pattern defect 13 occurs in the liquid crystal display unit 12 of one drive substrate 21, the entire three drive substrates 21 are good even though they are non-defective. Will be defective. That is, there is a problem similar to that of the liquid crystal display device 10 of FIG.

The present invention has been made in view of such a problem, and an object of the present invention is to provide an image display device capable of forming a large screen with a high production yield.

[0008]

An image display apparatus according to the present invention has a display section and a peripheral drive circuit for driving the display section, has an independent display function, and has a drive board having another similar configuration. And a driving substrate used in combination with the driving substrate. The driving substrate has a bonding area on a surface facing another driving substrate to be combined, and is combined with another substrate to form one driving substrate. The enlarged display unit is configured.

Another image display apparatus according to the present invention includes a plurality of drive boards, each having a display section and a peripheral drive circuit for driving the display section, having independent display functions, and being combined with each other. In addition, each of the plurality of driving substrates has a bonding region on a surface facing another adjacent driving substrate, and constitutes one enlarged display unit in a state where they are combined with each other.

In the image display device of the present invention, the driving substrates are independent, so that non-defective non-defective products and defective defective products are selected, and the driving substrates of only non-defective products are combined to reduce the number of driving substrates. The display screen is enlarged only.

In another image display apparatus according to the present invention, a plurality of drive boards each having an independent display function are combined with each other, and a display screen enlarged by combining non-defective non-defective drive boards is combined. It is formed.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a configuration of a liquid crystal display device according to an embodiment of the present invention. Here, only the planar configuration on the driving substrate side is shown, and the counter substrate is not shown.
The liquid crystal display device 100 includes a plurality of, for example, four drive substrates (TFT substrates) 101 to 104, and has a configuration in which the drive substrates 101 to 104 are combined so as to form a square shape as a whole.

The driving substrates 101 to 104 have substantially the same configuration as each other. That is, the drive substrates 101 to 1
04, a liquid crystal display 107 including a large number of TFTs arranged in a matrix,
And a peripheral driving circuit 110 including a vertical driving circuit 108 and a horizontal driving circuit 109 for driving the driving circuit 7, each having an independent display function.
Each of the liquid crystal display units 107 of the driving substrates 101 to 104 has, for example, an angle of view of 7 inches, and is combined so as to be continuous with each other to form an enlarged liquid crystal display unit having an angle of view of 14 inches.

The driving substrates 101 to 104 are each formed of a transparent material, for example, glass. Driving board 101
To 104 are bonding regions 11 on the surface facing the other driving substrate.
1 and 112 and are joined to each other by a joining material as described later. T formed on the driving substrates 101 to 104
As an FT (Thin Film Transistor), any of a so-called bottom gate type transistor shown in FIG. 2A and a top gate type transistor shown in FIG. 2B can be used. In the bottom gate type TFT, a gate electrode 151 is provided on a glass substrate 150, and a polycrystalline silicon thin film 153 recrystallized by laser irradiation is formed on the gate electrode 151 via a gate insulating film 152. ing. This polycrystalline silicon thin film 15
3 are provided with a source region 153a and a drain region 153b each formed by an N ⁺ diffusion layer. An interlayer insulating film 155 is provided on a channel region between the source region 153a and the drain region 153b of the polycrystalline silicon thin film 153, and an interlayer insulating film 156 is provided so as to cover the whole. A source electrode 154a and a drain electrode 154b are electrically connected to a source region 153a and a drain region 153b, respectively, through openings provided in the interlayer insulating film 156. On the other hand, in the top gate type TFT, the gate electrode 151 is formed on the polycrystalline silicon thin film 153.

As described above, the liquid crystal display device 100 according to the present embodiment has a drive substrate 101 having independent functions.
1 to 104 are directly joined to constitute one enlarged display screen. Therefore, a large liquid crystal display device 100 having no defect as a whole can be configured by selecting and combining drive substrates of only non-defective non-defective products. For example, when a pattern defect 113 is detected on the driving substrate 101 as shown in FIG. 3, the driving substrate 101 is deleted as a defective product, and a non-defective driving substrate 101 ′ having another similar configuration is replaced with the driving substrates 102 to 104. And the liquid crystal display device 100 may be integrated. Therefore, in the present embodiment, the three drive substrates 102 to 104
Is not wasted, and the production yield is improved as compared with the conventional method.

Next, a method of joining the respective drive substrates 101 (101 ') to 104 in the liquid crystal display device 100 will be described. It is necessary to consider both mechanical and electrical bonding for bonding. First, a mechanical joining method will be described.

FIG. 4 is a schematic cross-sectional view for explaining a method of joining the driving substrate 101 and the driving substrate 102 at the joining region 112 as an example. The color filters 115 on the driving substrates 101 and 102 schematically represent the positional relationship between the driving substrates 101 and 102 and the bonding region 112. The color filter 115 is formed on the counter substrate (not shown), and is not present when the driving substrate 101 and the driving substrate 102 are joined. The color filter 115 is provided with a black matrix 114 for shielding the periphery of each pixel electrode to improve display contrast. The black matrix 114 is also formed at a position facing the bonding region 112 between the driving substrates 101 and 102.

In the case where a large screen is formed by joining the small driving substrates 101 to 104 as in the present embodiment, depending on the connecting material, the light 117 incident on the joining portion may be different due to the difference in the scattering refractive index of the light. Are scattered, and the transmitted light 118 that should be shielded by the black matrix 114 passes through the color filter 115 and appears in the image, which causes image disturbance.

Therefore, in the present embodiment, the refractive index of the bonding material 116 is equivalent to that of the glass substrate used for the driving substrates 101 to 104 (for example, the refractive index is 1.45).
To 1.47), the driving substrate 10
1 and 102 are joined so as to form a smooth surface with each other. As a result, the light does not deviate in the joint region 112 between the driving substrates 101 and 102, and the image can be prevented from being disturbed. In this case, it is desirable that the thickness W _{1 of the} joining portion be within the width W ₂ of the black matrix 114.

The connected drive substrates 100, 1
01 does not form a smooth surface, the driving substrates 100 and 101
In some cases, the orientation of the liquid crystal layer filled between the substrate and the counter substrate is impaired, so that the displaced portion becomes a line and is displayed on a screen. Therefore, in the present embodiment, the bonding material 1
A support 119 as shown in FIG. 5 is provided on a bonding area 112 between the driving substrates 101 and 102 to be bonded by using 16. The support 119 has upper and lower flat surfaces, respectively, and connects the driving substrates 101 and 102 to each other with the bonding material 11.
6, the two driving substrates 101, 1
02 is provided so as to be a smooth surface. That is, the support 119 is formed on the lower flat surface 1.
19a is fixed so as to be in contact with the joint area 112 of the drive substrates 101 and 102. Next, after the opposing substrate 120 is disposed so as to be in contact with the upper flat surface 119b of the support 119, the opposing substrate 120 and the driving substrates 101, 1
The liquid crystal layer 121 is formed by filling a liquid crystal between the first and second liquid crystal layers.

The support 119 is desirably formed of a material having the same refractive index as the glass substrate for the same reason as the bonding material 116. Width W ₃ of the support 119 may be within a range capable of blocking the light passing through the support 119 by the black matrix 114, to retain the smooth surface of the two driving board 101, 102 a lower smooth surface 119a is adjacent If there is a suitable surface area, its plane shape is circular,
Any shape such as a square shape may be used. The height h of the support 119 is, for example, 3 μm in accordance with the thicknesses a and b (a = b) of the liquid crystal layer 121.
m.

FIG. 6 shows an installation location of the support 119 with respect to the four driving substrates 101 to 104. It is not necessary to provide the supports 119 corresponding to the entire area of the joining regions 111 and 112. For example, an appropriate number of supports 119 may be provided at equal or uneven intervals from the support 119 installed at the center. As a result, the liquid crystal layer is not interrupted at the boundary region, so that the liquid crystal can be injected from one place in the liquid crystal injection step.

Next, the liquid crystal display device 1 according to the present embodiment
A method for electrically connecting a drive circuit between the drive substrates 101 to 104 of FIG. FIG. 7 is a plan view showing a state in which the electrical connection is completed after the drive substrates 101 to 104 are mechanically joined to each other as described above. In the present embodiment, electrical bonding regions 130 to 134 are provided at respective ends of the mechanical bonding regions 111 and 112. The upper and lower electrical connection regions 130 and 132 connect the horizontal drive circuits 109 adjacent to each other on the left and right in the figure, and the left and right electrical connection regions 131 and 133 electrically connect the vertical drive circuits 108 vertically adjacent to each other in the figure. Connect. FIG. 8 shows, as an example, an electric connection region 1 between the driving substrates 102 and 103.
32 shows a specific configuration. In the electrical connection region 132, the lead lines 141 and 142 are extracted from the horizontal drive circuit 109 of each of the drive substrates 102 and 103, and the lead lines 141 and 142 are electrically connected by the bonding wires 140. The other electric connection regions 130, 131, and 133 have substantially the same configuration.
The four drive substrates 10 electrically connected at 134
1 to 104 operate continuously. Note that the lead lines 141 and 142 are formed at the same time when a drive circuit is formed on the drive substrate using a metal such as aluminum.
The wire bonding is performed after the mechanical bonding between the driving substrates 101 to 104 is completed.

Incidentally, such an electric connection region 13
Since 0 to 134 need to be provided outside the drive circuit, the area of the drive substrate needs to be increased accordingly.

FIG. 9 is a diagram for explaining a method for resolving such inconvenience. Here, an electrical connection method between the horizontal drive circuits 109 of the two drive boards 103 and 104 will be described. First, the operation of the horizontal drive circuit 109 on the drive substrate 103 will be briefly described. The horizontal drive circuit 109 includes a shift register 200, a phase matching circuit 201, and a signal control switch circuit 202. The shift register 200 has an external start signal ST1 and a clock signal CLK as shown in FIG.
1 and CLK2 are supplied.
That is, in the shift register 200, when the start signal ST1 is input, the clock signals CLK1, CLK
2, the selection pulse is sequentially shifted in the horizontal direction. These selection pulses are supplied to a signal control switch circuit 202 via a phase matching circuit 201, whereby an input video signal is selectively supplied to a signal line (not shown) corresponding to each pixel.

The shift register 200 generates an end signal ED1 when the shift of the last stage is completed. The end signal ED1 is supplied as a start signal ST2 to the horizontal drive circuit 109 of the adjacent drive substrate 104 via an external terminal 203A provided outside. That is, in the present embodiment, the shift register 20 on one drive substrate 103 side is used.
When the shift operation of the final stage is completed at 0, the end signal ED1 is output from the shift register 200,
This end signal ED1 is supplied to an external terminal 20 provided outside.
3A is supplied as a start signal ST2 to the shift register 200 on the other driving substrate 104 side via the
Thereafter, the same shift operation is performed. As a result, two adjacent screens are successively displayed, and function as one screen as a whole.

As described above, the end signal of the shift register 200 on one drive substrate 103 is supplied to the shift register 200 on the other drive substrate 104 via the external terminal 203, and this is used as a start signal. Since data can be transferred between independent drive substrates, there is no need to provide connection pads for data transfer on a substrate having a built-in drive circuit. Therefore, it is not necessary to increase the area of the drive substrate for the lead line region as shown in FIG. Note that data can be transferred not only between the horizontal drive circuits 109 but also between the vertical drive circuits 108 by the same method.

FIG. 10 shows a data transfer method between the vertical drive circuits 108 of the drive boards 101 and 103. The vertical drive circuit 108 includes a shift register 300 and a gate buffer 301. The start signal ST1 and the clock signals CLK1 and CLK2 from the outside as shown in FIG. 13 are also supplied to the shift register 300, respectively. When the shift operation is completed, an end signal ED1 is output from the shift register 300, and the end signal ED1 is transmitted to the adjacent shift register 300 on the other drive substrate 103 via an external terminal 203B provided outside. And the same shift operation is performed thereafter.

In the above example, the end signal of one drive board 103 is transmitted to the other drive board 10 via the external terminal 203.
Although the start signal is supplied to the fourth side, a method such as that shown in FIG. 11 may be used. Here, the vertical drive circuit 10 in the drive substrates 101 and 102 is used.
The data transfer between 8 will be described. Shift register 3
00 is supplied with an external start signal ST1 and clock signals CLK1 and CLK2. That is, here, an external counter 302A that counts in synchronization with the clock signals CLK1 and CLK2 is provided outside the driving substrates 101 and 102, and the count value of the external counter 302A is stored in the shift register 300 on the driving substrate 101 side. If the last radix is reached,
The start signal ST2 is supplied to the vertical drive circuit 108 on the drive substrate 102 side. FIG. 14 shows a timing chart in this case. Even with such a configuration, it is not necessary to increase the area of the drive substrate for the lead line region. Note that data can be transferred not only between the vertical drive circuits 108 but also between the horizontal drive circuits 109 using the external counter 302B in the same manner as shown in FIG.

Although the present invention has been described with reference to the embodiment, the present invention is not limited to the above embodiment, and can be variously modified within an equivalent range. For example, in the above-described embodiment, a case where a large screen is formed by combining four drive substrates has been described. However, the number is arbitrary and, for example, two substrates may be combined.

[0032]

As described above, according to the image display apparatus of the present invention, it is possible to provide an enlarged display section by including a drive board having an independent display function and joining with another drive board. As a result, a large-screen display device can be easily manufactured by combining only good driving substrates. In addition, an operation test for selecting a non-defective non-defective product from a defective defective product is simplified, and since only the non-defective product needs to be selected, the trouble of repairing the defect can be reduced, and the manufacturing yield is greatly improved. It works.

Another image display device according to the present invention comprises:
Since a plurality of driving boards each having an independent display function are combined, the enlarged display screen can be easily formed by combining non-defective non-defective driving boards. In addition, since only defective drive boards need to be removed and non-defective ones replaced, there is an effect that the production yield is improved in each step.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a specific structure of a thin film transistor used in the liquid crystal display device of FIG.

FIG. 3 is a plan view for explaining replacement of non-defective and defective drive substrates in the liquid crystal display device of FIG. 1;

FIG. 4 is a cross-sectional view for explaining a method of joining drive substrates in the liquid crystal display device of FIG.

5 is a cross-sectional view illustrating a configuration of a mounting portion of a support member in the liquid crystal display device of FIG.

6 is a plan view illustrating a configuration of a mounting portion of a support member in FIG.

FIG. 7 is a plan view for explaining an electrical connection means between drive circuits in the liquid crystal display device of FIG.

FIG. 8 is a partially enlarged view of the electrical connection part of FIG. 7;

FIG. 9 is a block diagram for explaining another electric connection means between horizontal drive circuits in the liquid crystal display device of FIG. 1;

FIG. 10 is a block diagram for explaining another electrical connection means between the vertical drive circuits in the liquid crystal display device of FIG.

11 is a block diagram for explaining still another electrical connection means between vertical drive circuits in the liquid crystal display device of FIG. 1. FIG.

FIG. 12 is a block diagram for explaining still another electrical connection means between horizontal drive circuits in the liquid crystal display device of FIG. 1;

FIG. 13 is a timing chart for explaining the operation of the liquid crystal display device shown in FIGS. 9 and 10;

FIG. 14 is a timing chart for explaining an operation of the liquid crystal display device of FIGS. 11 and 12.

FIG. 15 is a plan view of a driving substrate in a conventional large-sized liquid crystal device.

FIG. 16 is a plan view of a drive substrate of a large-sized liquid crystal device having another conventional configuration.

[Explanation of symbols]

100: liquid crystal display device, 101 to 104: drive substrate, 1
08 ... vertical drive circuit, 109 ... horizontal drive circuit, 111,
112: bonding area, 113: pattern defect, 116: bonding material, 119: support, 130 to 133: electrical bonding area, 203A, 203B: external terminal, 302A, 302
B: External counter

Claims (7)

[Claims] 1. An image including a driving board used in combination with a driving board having an independent display function and having a similar display structure, wherein a display section and a peripheral driving circuit for driving the display section are formed. A display device, wherein the driving substrate has a bonding area on a surface facing another driving substrate to be combined, and forms one enlarged display unit by being combined with another substrate. An image display device characterized by the above-mentioned. 2. An image display apparatus comprising: a plurality of drive boards each having a display unit and a peripheral drive circuit for driving the display unit, having independent display functions, and being combined with each other; Each of the driving substrates has a bonding region on a surface facing the other driving substrate adjacent thereto, and is combined with one another in a state where it is combined with one another.
An image display device comprising two enlarged display units. 3. The image according to claim 2, wherein the plurality of driving substrates are each formed of a transparent insulating substrate, and are joined to each other by a connecting material having the same refractive index as the transparent insulating substrate. Display device. 4. An image display apparatus comprising: a plurality of driving substrates combined to form one surface; and an opposing substrate disposed with an electro-optical material interposed therebetween, wherein a bonding region between the plurality of driving substrates is provided. 4. The image display device according to claim 3, further comprising: a support for maintaining a distance between the counter substrate and the counter substrate at a predetermined size. 5. The image display device according to claim 4, wherein the support has the same refractive index as the driving substrate. 6. A peripheral drive circuit formed on each of the plurality of drive boards includes a shift register, and transmits an end signal output from the last stage of the shift register provided on one drive board to an adjacent drive board. 3. The image display device according to claim 2, wherein the image display device is configured to be used as a start signal of a shift register provided in the image display device. 7. A peripheral driving circuit formed on each of the plurality of driving substrates includes a shift register, and counts a clock signal supplied to the shift register provided on one driving substrate by an external counter. 3. The image display device according to claim 2, wherein a start signal is supplied to a shift register provided on an adjacent drive substrate in accordance with a count result of the counter.