JP3364584B2 - Liquid crystal display - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in displays such as computers, televisions, personal digital assistants, and in-vehicle navigation systems. By applying a drive signal to a display pixel electrode via a switching element,
The present invention relates to a liquid crystal display device for displaying.

[0002]

2. Description of the Related Art An active matrix type liquid crystal display device is obtained by bonding an active matrix substrate and a counter substrate and enclosing a liquid crystal between the substrates. The active matrix substrate is obtained by forming a thin film and patterning a plurality of times on a glass substrate to form active elements, wirings, and pixel electrodes. As an active element, aS
The case of using an iTFT (thin film transistor) will be described. A gate metal is formed on a glass substrate by sputtering, and is patterned by photolithography and etching to form a gate wiring which is a scanning wiring. Next, a gate insulating film, a semiconductor layer, and a contact layer are continuously formed, and the semiconductor layer and the contact layer are patterned in an island shape. Next, a source metal is formed into a thin film by sputtering, and this is patterned, and the contact layer in the channel portion of the TFT is also removed. Further, a transparent electrode made of ITO is formed, and this is patterned into a pixel electrode. Finally, a protective film is formed by CVD to form an active matrix substrate. Then, after applying an alignment film on the active matrix substrate, rubbing treatment is performed.

A transparent electrode and a color filter are formed on a counter substrate, which is one of the glass substrates. Then, after applying an alignment film on the counter substrate, rubbing treatment is performed. Next, the two substrates are bonded together, and liquid crystal is sealed between the substrates to obtain a liquid crystal display device.

[0004]

As one of the directions for expanding the applications of liquid crystal display devices, there is an increase in size. At present, a liquid crystal display device having a diagonal size of about 15 to 20 inches is put to practical use on a commercial basis. However, for further size increase, the manufacturing technology at a cost commensurate with the market has not been established. Therefore, a large-screen wall-mounted television using a liquid crystal display device is not yet in the prototype stage.

Although there are many problems in increasing the screen size, the major problem is that the wiring becomes long and the wiring resistance increases, so that the signal delay time increases,
As the number of pixels increases, the number of defects also increases, which raises a problem that the manufacturing yield rate decreases.

The present invention provides a liquid crystal display device in which defects between wirings hardly occur, the capacity of the wirings can be reduced, and the aperture ratio can be improved.

[0007]

A liquid crystal display device according to claim 1, wherein a plurality of strip-shaped substrates on which a metal film is formed is used, and the metal film formation surface of the strip-shaped substrates and the metal are formed. A new substrate is formed by combining the back surface of the film forming surface, and the metal film formed on the combined surface of the strip-shaped substrates is used as the scanning wiring, and on the newly formed substrate, A plurality of signal wirings are formed so as to intersect the scanning wirings in a three-dimensional manner, and a switching element and a pixel electrode are provided in the vicinity of an intersection of the signal wirings and the scanning wirings.

A liquid crystal display device according to a second aspect is characterized in that a metal film is formed on the back surface of the metal film formation surface of the strip-shaped substrate.

According to a third aspect of the present invention, the liquid crystal display device is characterized in that an insulating adhesive is interposed on both sides of the surface on which the plurality of strip-shaped substrates are combined.

The operation of the above configuration will be described. Claim 1
According to the configuration of the liquid crystal display device described above, the gate wiring, which is the scanning wiring, exists on the adhesive surface of the substrate on the strip, so that the gate wiring does not intersect with the source wiring, which is the signal wiring, on the plane. Therefore, there is almost no leakage between the wirings due to the loss of the interlayer insulating film. Further, since no capacitance is formed between the gate wiring and the source wiring and between the gate wiring and the counter electrode, the capacitance of the gate wiring can be reduced. Further, the wiring resistance of the gate wiring can be made sufficiently low by changing the width of the strip-shaped substrate. Therefore, the delay time can be reduced due to the low resistance and low capacitance of the gate wiring. Further, since the gate wiring is not present on the plane, the aperture ratio can be improved and bright display can be realized.

According to the liquid crystal display device of the second aspect, since the gate wirings are formed on both surfaces of the strip-shaped substrate and the gate wirings are bonded with the insulating adhesive, they are used as different gate wirings. can do. That is, the number of gate wirings can be doubled. Furthermore, two rows of pixel electrodes can be formed on one strip-shaped substrate, and higher-definition display can be performed.

According to the liquid crystal display device of the third aspect, the substrate can be newly formed by the adhesive. Furthermore, since the gate wiring is formed on both surfaces of the strip-shaped substrate and the gate wiring is bonded with the insulating adhesive, no leak occurs between the adjacent gate wirings.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings. (Embodiment 1) As shown in FIG. 1, a metal thin film is formed on the surface of an insulating substrate 1 such as glass. This Embodiment 1
Then, a glass plate is used as the substrate 1. This metal thin film is a metal thin film to be used as a gate wiring which is a scanning wiring. After forming this metal thin film, the substrate 1 is divided into a plurality of strips 2. Since the width to be divided is used as a gate wiring, the width is calculated and set from the resistivity of the metal thin film so as not to become wiring resistance. Strip 2 made by dividing
The metal thin film surface is referred to as A surface and the back surface thereof is referred to as B surface.

Next, as shown in FIG. 2, the strips 2 are attached to each other by using an insulating adhesive or the like so that the A side and the B side of the strips 2 are in close contact with each other. The new substrate formed by the bonding is referred to as the substrate 10 for convenience. The metal thin film on this bonded surface is the gate wiring. The number of the strips 2 is the same as the number of the gate wirings of the display to be manufactured. For example, in the case of VGA display, 480 strips 2 are prepared. The 480 pieces are adhered to produce a substrate 10 made of a glass plate having a metal thin film surface (A surface) as an end surface. The new surface (C surface) of this substrate 10 is polished and flattened.

Next, as shown in FIG. 3, a metal thin film is formed on the C surface and patterned to form a gate electrode 21 of the TFT. The gate electrode 21 is formed so as to be electrically connected to the gate wiring 20 existing on the adhesive surface.
The pitch P between the gate electrodes 21 is the thickness of the strip 2, that is, the thickness of the glass plate which is the substrate 1 before the division.

Next, a gate insulating film, a semiconductor layer, and a contact layer are formed and patterned into a predetermined shape.
Subsequently, as shown in FIG. 4, a thin film of a metal to be the source wiring 30 which is a signal wiring is formed, and the source wiring 30 and T
The source electrode 31 and the drain electrode 32 of FT3 are formed.

Next, as shown in FIG. 5, a pixel electrode 50 is formed using a transparent electrode. Finally, a protective film is formed and patterning is performed to expose the terminal portion, and the active matrix substrate 4 is completed. A substrate newly formed by bonding the strips 2 together is referred to as an active matrix substrate 4.

Then, a counter substrate having a counter electrode formed thereon,
A liquid crystal display device is completed by bonding the active matrix substrate 4 and injecting liquid crystal between the substrates.

(Second Embodiment) In the second embodiment, the diagonal is 1 m.
Manufacturing of the SVGA display liquid crystal display device will be described in detail with reference to the drawings. This active matrix substrate 4
The completed drawing is shown in FIG. The same parts as those of the first embodiment will be described with reference to the drawings of the first embodiment.

As shown in FIGS. 1, 2 and 7, the thickness is 1 m.
A metal thin film is formed on the glass plate of m by the sputtering method. In the second embodiment, Ta is used as the metal material. A suitable film thickness is 150 nm to 500 nm,
In the second embodiment, the thickness is 250 nm. Next, the glass plate is cut into strips 2 by using the dicing method. The width of the strip 2 is 1 mm and the length is 800 mm or more. The metal thin film surface of the strip 2 formed by the division is referred to as A surface, and the back surface thereof is referred to as B surface. The strips 2 are attached to each other with an insulating adhesive so that the A side and the B side of the strips 2 are in close contact with each other, and the strips are bundled into a substrate. By using 600 strips 2, the display area of the bonded substrates is 600 mm x 800 m
m liquid crystal display device can be manufactured. A strip 11 having the same thickness and a large width is attached to both sides of the strip 2, and this portion is used as a seal portion, a frame portion, and a source terminal portion.

The new substrate formed by pasting together is called the substrate 10 for convenience. The gate wiring 20 exists on the bonding surface of the substrate 10. In the case of the second embodiment, the Ta wiring has a length of 800 mm, a width of 1 mm, and a thickness of 250 nm.
If the specific resistance of a is 25 μΩcm, the wiring resistance is 800
Becomes Ω. This value is remarkably small as compared with the case of a normal process of forming on a glass substrate, and is a sufficient value for producing a large substrate.

Next, as shown in FIG. 3, the surface of the substrate 10 is polished and flattened, and then the sputtering method is used.
Ta is formed and patterned to form the gate electrode 21 of the TFT and the terminal portion of the gate wiring. Gate wiring 20
Exists on the bonding surface. The pitch P between the gate electrodes 21 is the thickness of the strip 2, that is, the thickness 1 of the glass plate before division.
mm.

FIG. 8 shows a sectional view of the TFT 3 of FIG. 6 taken along the line XX. Next, by CVD, a gate insulating film 40 made of silicon nitride, a semiconductor layer 41 made of amorphous silicon, and a contact layer 42 made of amorphous silicon as n ⁺ are formed. The semiconductor layer 41 and the contact layer 42 are patterned into an island shape by using dry etching. Next, the gate insulating film 40 is etched to form a contact hole in the terminal portion.

As shown in FIG. 6, a metal thin film to be the source wiring 30 is formed by sputtering, and the source wiring 30 is formed.
The terminal portion of the source wiring, the source electrode 31 and the drain electrode 32 of the TFT 3 are formed. At this time, the wiring pitch of the source wirings 30 is set to 1/3 mm.

Next, as shown in FIG. 8, the contact layer 42 in the channel portion of the TFT 3 is removed by etching to remove TF.
Complete T3. A transparent electrode made of ITO is formed thereon by a sputtering method and etched to form a pixel electrode 50. Finally, a protective film 60 made of silicon nitride is formed by the CVD method and patterned to complete the active matrix substrate 4. A substrate newly formed by bonding the strips 2 together is referred to as an active matrix substrate 4.

After that, the counter substrate on which the counter electrode and the color filter are formed is bonded to the active matrix substrate, and liquid crystal is injected between the substrates to complete the liquid crystal display device.

In color display, since one color pixel electrode is formed by three pixel electrodes of RGB, the color pixel electrode has a size of 1 mm square. When an SVGA display screen is produced with this size, the diagonal is 1 m, the width is 800 mm and the length is 60 mm.
A 0 mm liquid crystal display device can be obtained.

(Embodiment 3) Embodiment 3 is Embodiment 2
Using a glass substrate having the same thickness as in (1), it is possible to perform display with higher definition than in the second embodiment. In the description of the third embodiment, only the points different from the second embodiment will be mainly described.

As shown in FIG. 7, metal thin films are formed on both surfaces of a glass plate having a thickness of 1 mm by the sputtering method. That is, metal thin films are formed on the A and B surfaces of FIGS. Next, the glass plate is divided into strips 2 by using the dicing method. The metal thin film surfaces of the strips 2 formed by the division are adhered to each other using an insulating adhesive so that the metal thin film surfaces adhere to each other, and these are bundled to form a substrate. The new substrate formed by the bonding is referred to as the substrate 10 for convenience. Board 10
The pixel electrode 50 and the TFT 3 are formed on the second embodiment.
However, in Embodiment 3, since metal thin films are formed on both surfaces of the strip 2 and the metal thin film surfaces are bonded by an insulating adhesive, they can be used as different gate wirings. Therefore, two rows of pixel electrodes can be formed on one strip 2 and higher definition display can be performed.

As shown in FIG. 9, a gate electrode 21 is formed on the substrate 10. The gate wiring 20 exists on the bonding surface. At this time, the gate electrodes 21 adjacent to each other are formed so as not to leak.

Next, as shown in FIG. 10, the source wiring 3
0, the source electrode 31 and the drain electrode 32 of the TFT 3 are formed. Further, a transparent electrode made of ITO is formed by a sputtering method and etched to form the pixel electrode 50. Finally, a protective film made of silicon nitride is formed by the CVD method and patterned to complete the active matrix substrate 4. A substrate newly formed by bonding the strips 2 together is referred to as an active matrix substrate 4.

With such a configuration, by disposing the gate electrode 21, only one row of pixel electrodes 50 could be formed on the strip 2 in the second embodiment. However, as shown in FIG. The 50 can be formed in two rows.

With such a structure, the number of gate wirings 20 can be doubled. The steps after forming the gate electrode 21 are different only in the shape of the patterning mask, and the forming method can be the same as that of the second embodiment.

As described above, the following effects can be obtained by adopting the configurations of the first to third embodiments. Since the gate wiring exists on the adhesive surface of the strip, the gate wiring does not intersect the source wiring on the plane. Therefore, there is almost no leakage between the wirings due to the loss of the interlayer insulating film. Further, since no capacitance is formed between the gate wiring and the source wiring and between the gate wiring and the counter electrode, the capacitance of the gate wiring can be reduced. In addition, a sufficiently low wiring resistance of the gate wiring can be dealt with by changing the width of the strip.
The delay time can be reduced due to the low resistance and low capacitance of the gate wiring. Since the gate wiring does not exist on the plane, the aperture ratio can be improved and bright display can be achieved.

[0035]

EFFECTS OF THE INVENTION By adopting the constitution of the present invention, the following effects are obtained. Since the gate wiring exists on the adhesive surface of the strip, the gate wiring does not intersect the source wiring on the plane. Therefore, there is almost no leakage between the wirings due to the loss of the interlayer insulating film. Further, since no capacitance is formed between the gate wiring and the source wiring and between the gate wiring and the counter electrode, the capacitance of the gate wiring can be reduced. In addition, a sufficiently low wiring resistance of the gate wiring can be dealt with by changing the width of the strip. Therefore, the delay time can be reduced due to the low resistance and low capacitance of the gate wiring. Since the gate wiring does not exist on the plane, the aperture ratio can be improved and bright display can be achieved.

Further, since the gate wirings are formed on both sides of the strip and the gate wirings are adhered by an insulating adhesive, they can be used as different gate wirings. That is, the number of gate wirings can be doubled. Furthermore, two rows of pixel electrodes can be formed on one strip, and higher-definition display can be performed.

Further, when the gate wirings are formed on both sides of the strip, the gate wirings are adhered with an insulating adhesive, so that no leak occurs between the adjacent gate wirings.

[Brief description of drawings]

FIG. 1 is a diagram showing a method of manufacturing a strip 2.

FIG. 2 is a diagram showing a method of manufacturing a substrate 10 configured by sticking strips 2 together.

FIG. 3 is a diagram showing formation of a gate electrode 21.

FIG. 4 is a diagram showing formation of a TFT 3 and a source wiring 30.

FIG. 5 is a diagram showing formation of a pixel electrode 50.

FIG. 6 is a diagram showing an active matrix substrate 4 according to a second embodiment.

FIG. 7 is a diagram showing a configuration of a strip 2 according to the second embodiment.

8 is a sectional view taken along line XX of FIG.

FIG. 9 is a diagram showing the formation of the gate electrode 21 of the third embodiment.

FIG. 10 is a diagram showing an active matrix substrate 4 according to a third embodiment.

[Explanation of symbols]

1 10 substrate 2 11 strips 3 TFT 4 Active matrix substrate 20 gate wiring 21 Gate electrode 30 source wiring 31 source electrode 32 drain electrode 40 Gate insulation film 41 Semiconductor layer 42 Contact layer 50 pixel electrodes 60 protective film

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-1-195420 (JP, A) JP-A-6-151463 (JP, A) JP-A-9-258262 (JP, A) JP-A-63- 167332 (JP, A) Special table HEI 7-504044 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G02F 1/1333 G02F 1/1343 G02F 1/1368

Claims (3)

(57) [Claims] 1. A plurality of strip-shaped substrates on which a metal film is formed is used, and a new substrate is formed by combining the metal film formation surface of the strip-shaped substrate and the back surface of the metal film formation surface. And using the metal film formed on the surface formed by combining the strip-shaped substrates as scanning wiring, and forming a plurality of signal wirings on the newly-configured substrate so as to intersect the scanning wiring in a three-dimensional manner. A liquid crystal display device, wherein a switching element and a pixel electrode are provided near an intersection of the signal line and the scanning line. 2. A metal film is formed on the back surface of the metal film formation surface of the strip-shaped substrate.
The described liquid crystal display device. 3. The liquid crystal display device according to claim 1, wherein an insulating adhesive is provided on both surfaces of a surface where a plurality of strip-shaped substrates are combined.