JP3043869B2 - Liquid crystal display - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display.

[0002]

2. Description of the Related Art Liquid crystal displays (liquid crystal display devices) can be reduced in weight and thickness and have low power consumption, so that they have been applied to, for example, displays of portable TVs and laptop personal computers. R & D of high definition is being conducted in various places.

As a matrix substrate for driving a liquid crystal, for example, as shown in FIG. 20 or FIG. 21, a plurality of address wirings 2 and data wirings 3 which intersect each other, amorphous Si (hereinafter abbreviated as a-Si) or Poly Si
2. Description of the Related Art An active matrix substrate in which thin film transistors 4 (or MIM elements) formed of (hereinafter abbreviated as p-Si) are arranged on a substrate is known. The liquid crystal display device is configured by sealing liquid crystal between the liquid crystal driving active matrix substrate and the counter substrate.

In order to protect an active matrix substrate for driving a liquid crystal from deterioration due to static electricity, Japanese Patent Application Laid-Open
As described in Japanese Patent Application Laid-Open No. 61-59475, there is known a structure in which an address wiring and a data wiring are short-circuited to a short-circuit line formed using a wiring material in a region other than a display region.

However, in this case, lighting evaluation of the liquid crystal display device cannot be performed until the short-circuit line is cut off. In other words, before the short-circuit lines are cut off, line defects such as address lines and data lines can be detected, but the characteristics of the elements in the display area cannot be evaluated, so that point defects cannot be detected. In addition, short-circuit lines to protect against static electricity are cut off when the liquid crystal display device is completed.
After the release of the short-circuit line, the structure is easily affected by static electricity.

For this reason, as disclosed in, for example, Japanese Patent Application Laid-Open No. 63-220289, the address wiring and the data wiring, or the wiring and the short-circuit line are separately connected to each other via a two-terminal operation thin film transistor or the like. It is conceivable to make an electrical connection.

However, since the protective insulating film on the channel of the thin film transistor forming the resistor is exposed, the charge tends to accumulate under the influence of external static electricity. As a result, the electrical characteristics of the thin film transistor forming the resistor are reduced. Is not stable, or the thin film transistor is broken, so that a stable resistance cannot be supplied.

[0008]

As described above, in the conventional liquid crystal display device, the address wiring and the data wiring are separately provided via a two-terminal operation thin film transistor or the like in order to protect against static electricity and detect a point defect at the time of manufacturing. It is conceivable that they are electrically connected to each other. However, since the protective insulating film on the channel is exposed, electric charges easily accumulate under the influence of static electricity from the outside. However, there is a problem that stable characteristics cannot be supplied because the characteristic is unstable or the thin film transistor is broken.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem. In order to protect a liquid crystal display device against static electricity and to detect a point defect in a manufacturing process, an address wiring and a data wiring are connected via a resistor. The purpose of the present invention is to provide a liquid crystal display device that is hardly affected by static electricity by inserting a resistor formed of a thin film transistor that is not easily affected by static electricity between the wiring and the short circuit line in a liquid crystal display device connected to a short-circuit line. I have.

[0010]

According to the present invention, there is provided an insulating transparent substrate, a plurality of address wirings formed in a display area on the insulating transparent substrate, and a plurality of address wirings intersecting the address wirings. A plurality of data wirings formed as described above, a thin film transistor formed at each intersection of the address wiring and the data wiring, a gate electrode is electrically connected to the address wiring, and a drain electrode is electrically connected to the data wiring, A pixel electrode formed near each of the intersections and electrically connected to the source electrode of the thin film transistor and the address wiring and the data wiring in a region other than the display region on the insulating transparent substrate via a resistor. A short-circuit line for short-circuiting, wherein each of the resistors comprises a thin-film transistor covered with a diagonal film; Light film is characterized in that it is short-circuited to at least one of all the other oblique film, said address lines, the data lines or the short-circuit line.

[0011]

In the liquid crystal display device of the present invention, a thin film transistor for forming a resistor inserted between an address wiring and a data wiring and a short-circuit line for protection against static electricity and for detecting a point defect in a manufacturing process is formed on a channel. Since the film has the oblique light oblique film, the channel portion can be prevented from being charged by external static electricity. Therefore, a stable resistance value can be supplied irrespective of static electricity, and the anti-static property of the active matrix substrate is improved. In addition, the present invention
The essence of the effect is that the thin film transistor is covered with the oblique light film, thereby preventing a decrease in the resistance value of the thin film transistor due to a light leakage current and stabilizing the resistance value. It also has the effect of being able to do it.

[0012]

Embodiments of the present invention will be described below.

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

In FIG. 1, reference numeral 1 denotes an insulating transparent substrate.

In the display area on the insulating transparent substrate 1, a plurality of address lines 2, 2,...
Are formed so as to intersect with. A thin film transistor (hereinafter, referred to as TFT) 4 is formed at each intersection of the address wiring 2 and the data wiring 3, a gate electrode 4 a thereof is electrically connected to the address wiring 2, and a drain electrode 4 b thereof is provided. The source electrode 4c is electrically connected to the data line 3, and the source electrode 4c is electrically connected to the pixel electrode 5 formed near the intersection.

A capacitor 7 is formed by sandwiching a liquid crystal (dielectric) between the pixel electrode 5 and the counter substrate 6.

Each address wiring 2 and data wiring 3
It extends outside the display area, and is electrically connected to driving pulse input pads 8 and 9 formed in the extending portion.

Each address wiring 2 and data wiring 3
The driving pulse input pads 8 and 9 further extend and are electrically connected to resistors 10 formed at their terminals. Here, the configuration of the resistor 10 will be specifically described.

The resistor 10 mainly includes two TFTs 11 and 12.
Consists of

The drain electrode 11a and the gate electrode 11b of the TFT 11 and the source electrode 12c of the TFT 12 are electrically connected to the driving pulse input pad 8 (or 9).

The drain electrode 12a and gate electrode 12b of the TFT 12 and the source electrode 11c of the TFT 11 are electrically connected to a short-circuit line 13 for short-circuiting all the resistors 10.

The TFTs 11 and 12 are covered with an oblique light film 14 for blocking the incidence of light from the outside such as a backlight, and these oblique light films 14 are used to short-circuit all the oblique light films 14. It is electrically connected to the film short-circuit line 15.

Here, an enlarged view of the resistor 10 is shown in FIG.
3 and 4 are enlarged sectional views taken along lines aa 'and bb' of FIG.

As shown in these figures, gate electrodes 11b and 12b are formed on the insulating transparent substrate 1, and a gate insulating film 16 is formed so as to cover them.

The a-Si film 1 is formed on the gate insulating film 16.
7, drain electrode 11a, 12a and source electrode 11 via channel protective film 18 and n ⁺ a-Si film 19
c and 12c are formed.

The oblique light film 14 is formed so as to cover them with a protective insulating film 20 interposed therebetween.

The drain electrodes 11a, 12a and the gate electrodes 11b, 12b are electrically connected by through holes 21.

In the liquid crystal display device having such a configuration, if the address wiring 2 or the data wiring 3 is charged positively or negatively with respect to the potential of the short circuit line 13 by static electricity in a manufacturing process or the like,
A current flows between the address line 2 or the data line 3 and the short-circuit line 13 in the direction of canceling out the charge via the resistor 10, and the address line 2 (or the data line 3) and the short-circuit line 1
3 Further, a voltage generated between the data wiring 3 and the address wiring 2 can be suppressed. Further, a resistor 10 is provided between the address line 2 and the data line 3 and the short-circuit line 13.
, The TFT characteristics in the display area can be measured without cutting off the short-circuit line 13.

Moreover, in the liquid crystal display device according to the present invention,
Since the conductive oblique light film 14 is provided on the channel portions of the TFTs 11 and 12 constituting the resistor 10, the TFT is hardly affected by external static electricity and the TFT is not easily broken. Therefore, a stable resistance can be supplied, and the anti-static property of the active matrix substrate is improved.

Similarly, even if strong light from a backlight or the like is incident on the resistor 10, a decrease in the resistance value due to light leakage current can be prevented, and the resistor 1 having a stable resistance value can be prevented.
0 can be supplied.

The short-circuit line 13 may or may not be cut off by the time the product is completed. If the short-circuit line 13 is left without being cut off, it is less susceptible to static electricity even after the product is completed.

Next, a method of manufacturing the liquid crystal display device will be described (see FIG. 3).

(1) A first wiring material such as MoT is formed on an insulating transparent substrate 1 such as a glass substrate by a sputtering method.
a is formed to a thickness of 250 nm, patterned and etched by Chemical Dry Etching (hereinafter abbreviated as CDE) to form address wiring 1, gate electrodes 11b and 12b and address wiring driving pulse input pads 8 and 9. I do.

(2) As the gate insulating film 16, a plasma C
Forming a SiO _X film thickness of about 350nm by VD method to form.

(3) a-Si film 17 and channel protection film 18
As a result, SiN _x was deposited by plasma CVD for 50
nm, 200 nm.

(4) Etching is performed with a hydrofluoric acid-based etching solution in order to pattern the SiN _x of the channel protection film 18.

(5) n ⁺ a for making contact between the source electrodes 11c and 12c and the drain electrodes 11a and 12a.
Forming a 50 nm Si film 19 by a plasma CVD method;

(6) In order to pattern the pattern of the a-Si film 17, the n ⁺ a-Si films 19, a-
The Si film 17 is etched.

(7) ITO is formed to a thickness of 100 nm as the pixel electrode 5 by sputtering, patterned, and etched with an aqua regia-based etching solution.

(8) The gate insulating film 16 is formed by patterning the gate insulating film through hole 21 and etching with an ammonium fluoride solution.

(9) A second wiring material by a sputtering method,
Cr and Al are laminated and deposited to a thickness of 50 nm and 500 nm, respectively, and as a patterning, Cr and Al are respectively etched with a mixed solution of phosphoric acid and acetic acid nitrate and a solution of cerium ammonium nitrate. , 12a and pulse input pads 8 and 9 for driving data lines.

(10) The n ⁺ a-Si film 19 exposed between the source electrodes 11c and 12c and the drain electrodes 11a and 12a
With the source 11c, 12c and the drain electrode 11a,
Using CD as a mask, etching and removal are performed by CDE.

(11) As the protective insulating film 19, a plasma CV
A 200 nm SiN _x film is formed by the method D, the protective insulating film through-hole 21 is patterned, and etched by reactive ion etching (hereinafter abbreviated as RIE). (12) Cr is deposited to a thickness of 200 nm by sputtering, patterned, and etched with a cerium ammonium nitrate solution to form a light-shielding film 14.

By the above manufacturing method, a required liquid crystal driving active matrix substrate can be manufactured.

The TFT manufactured by the above steps
Since the TFTs 11 and 12 have substantially the same structure as the TFT 4 formed at each intersection of the address wiring 2 and the data wiring 3, the formation of the TFTs 11 and 12 and the formation of the TFT 4 can be performed simultaneously. The manufacturing process can be simplified.

Further, the active matrix substrate according to the present invention provides a wiring material other than MoTa formed by sputtering on the first wiring material, for example, Mo, Ta, Ta formed by sputtering or vapor deposition.
N, Cr, Al, Al-Si-Cu, W, ITO, C
u, an alloy containing them as a main component, or a laminated film thereof can also be used.

The plasma C is used as the gate insulating film 16.
In addition to SiO _X by the VD method, an anodic oxide film of the first wiring material, SiO _X formed by the sputtering method,
SiN _x , TaO _x , S formed by plasma CDV method
iN _X or may be used a laminated film thereof.

Further, in addition to the Cr and Al laminated films formed on the second wiring material by the sputtering method, Mo, A formed by the sputtering method or the vapor deposition method.
1, Cr, Cu, Ti, Ta, TaN, Al-Si-C
u, W, ITO, an alloy containing these as a main component, or a stacked film thereof may be used.

Further, the channel protective film 18 may be made of not only SiN _x formed by the plasma CVD method but also SiO _x , SiN _x , plasma CV formed by the sputtering method.
SiO _X , SiN _X formed by the method D or a laminated film thereof may be used.

The protective insulating film 19 is formed by plasma CVD.
Besides the SiN _X formed by law, SiO _X formed by sputtering, SiN _X, SiO _X formed by a plasma CVD method may be used SiN _X or a laminated film thereof.

Further, the light-shielding film 14 may be formed of Mo, Al, Cr, Cu, Ti, T
a, TaN, Al-Si-Cu, W, an alloy containing these as a main component, or a stacked film thereof may be used.

Further, a structure having a protective film above the light shielding film 14 may be employed, or a structure having no channel protective film independent of the channel portion of the TFT may be employed.

The structure of the TFT constituting the resistor 10 may be, for example, a top gate type or a coplanar type as long as the light shielding film 14 is present on the side facing the gate electrode. P- instead of Si
Si may be used.

Next, FIG. 5 is an equivalent circuit diagram of the second embodiment of the present invention, FIG. 6 is an enlarged view thereof, and FIG.
7 and 8 show enlarged cross-sectional views taken along the line b '.

In the second embodiment, each of the light-shielding films 14 and 14 of the two TFTs 11 and 12 constituting the resistor 10
Of the source electrodes 11c and 12c or the drain electrodes 11a and 12a of the FTs 11 and 12, the gate electrodes 11b and 12
The electrode on the side not connected to b is connected via a protective insulating film through hole 22. Other structures are the same as in the first embodiment.

Next, FIG. 9 shows an equivalent circuit diagram of the third embodiment of the present invention.

In the third embodiment, each of the light-shielding films 14 and 14 of the two TFTs 11 and 12 constituting
Of the source electrodes 11c and 12c or the drain electrodes 11a and 12a of the FTs 11 and 12, the gate electrodes 11b and 12
b through the protective insulating film through hole 2
2 are connected. Other structures are the same as in the second embodiment.

Next, FIG. 10 shows an equivalent circuit diagram of the fourth embodiment of the present invention.

In the fourth embodiment, the light-shielding films 14 of the two TFTs 11 and 12 constituting the resistor 10 are connected to the short-circuit line 13. Other structures are the same as in the second embodiment.

Next, FIG. 11 shows an equivalent circuit diagram of the fifth embodiment of the present invention.

In the fifth embodiment, the light-shielding films 14 of the two TFTs 11 and 12 constituting the resistor 10 are connected to the driving pulse input pads 8 and 9, respectively. Other structures are second
This is the same as the embodiment.

Next, FIG. 12 shows an equivalent circuit diagram of the sixth embodiment of the present invention.

In the sixth embodiment, the resistor 10 has one TF
It is composed of T11. Then, the gate electrode 11b of the TFT 11 is connected to the driving pulse input pads 8 and 9 side,
The light-shielding film 14 is connected to the short-circuit line 13. This embodiment has an effect that one TFT can obtain the same resistance value as the above-described embodiment having two TFTs.
Next, FIG. 13 shows an equivalent circuit diagram of the seventh embodiment of the present invention.

In the seventh embodiment, similarly to the sixth embodiment, the resistor 10 is constituted by one TFT 11. The gate electrode 11b of the TFT 11 is connected to the short-circuit line 13, and the light-shielding film 14 is connected to the driving pulse input pads 8, 9. This embodiment is similar to the sixth embodiment in that 1
One TFT has an effect that a resistance value similar to that of the above-described embodiment having two TFTs can be obtained.

Next, FIG. 14 shows an equivalent circuit diagram of the eighth embodiment of the present invention.

In the first to seventh embodiments, the resistor 10 is inserted between the driving pulse input pads 8 and 9 and the short-circuit line 13, but in the eighth embodiment, the address wiring 2
Alternatively, it has a structure in which a resistor 10 is inserted between the data lines 3. The structure of the resistor 10 inserted between the address wiring 2 or the data wiring 3 may adopt any of the structures shown in the first to seventh embodiments.

Next, FIG. 15 shows an equivalent circuit diagram of the ninth embodiment of the present invention.

In the eighth embodiment, the resistor 10 is inserted between the address wiring 2 and the data wiring 3 outside the driving pulse input pads 8 and 9, but in the ninth embodiment, Display area and driving pulse input pads 8 and 9
A resistor 10 is inserted between the address wiring 2 or the data wiring 3 in a region between the two. As in the eighth embodiment, the structure of the resistor 10 inserted between the address wiring 2 or the data wiring 3 may employ any of the structures shown in the first to seventh embodiments.

Next, FIG. 16 shows an equivalent circuit diagram of the tenth embodiment of the present invention.

In the tenth embodiment, the present invention is applied to a liquid crystal display device in which the data lines 3 are drawn alternately or alternately. The structure of the resistor 10 inserted between the driving pulse input pads 8, 9 and the short-circuit line 13 may adopt any of the structures shown in the first to seventh embodiments.

Next, FIG. 17 shows an equivalent circuit diagram of the eleventh embodiment of the present invention.

In the eleventh embodiment, the present invention is applied to a liquid crystal display device in which the data lines 3 are drawn alternately or every other line. Between wiring 3
This is a structure in which the resistor 10 is inserted. Resistor 1 inserted between drive pulse input pads 8 and 9 and short-circuit line 13
The structure 0 may adopt any of the structures shown in the first to seventh embodiments.

Next, FIG. 18 shows an equivalent circuit diagram of the twelfth embodiment of the present invention.

The twelfth embodiment is different from the ninth embodiment in that a short-circuit line 13 which is not directly connected to the resistor 10 is formed outside. The short-circuit line 13 is connected during the array process, and is disconnected when it becomes unnecessary during inspection or the like. Even if the short-circuit line 13 is cut off, the address wiring 2 and the data wiring 3 are connected via the resistor 10, so that the structure is hardly affected by static electricity.

Next, FIG. 19 shows an equivalent circuit diagram of the thirteenth embodiment of the present invention.

The thirteenth embodiment is an example in which the address wiring 2 or the data wiring 2 is connected by a resistor 10 every other line or every several lines in the twelfth embodiment. In the first to thirteenth embodiments described above,
Although the present invention is applied to a liquid crystal driving active matrix substrate having a structure without an auxiliary capacitance, the present invention is also applicable to a liquid crystal driving active matrix substrate having a structure having an auxiliary capacitance.

Further, a structure may be employed in which an auxiliary capacitance line or a pad for controlling the potential of an electrode on the opposite substrate is connected to the short-circuit line 13 via the resistor 10.

The position where the resistor 10 is further connected may be near both ends of the wiring or on either one side.

[0079]

In the liquid crystal display device according to the present invention, a resistor is inserted between the address line and the data line and the short-circuit line for protecting the active matrix substrate for driving the liquid crystal against static electricity and detecting a point defect during the manufacturing process. Since the thin film transistor that forms the resistor has a conductive oblique film, the thin film transistor is less likely to be damaged by external static electricity and is less affected by the electrical characteristics, and has a stable resistance value. Can be supplied. As a result, the anti-static property of the active matrix substrate is improved.

[Brief description of the drawings]

FIG. 1 is an equivalent circuit diagram of a first embodiment of the present invention.

FIG. 2 is an enlarged view of a TFT resistor portion according to the first embodiment of the present invention.

FIG. 3 is an enlarged cross-sectional view (between aa ′) of the TFT resistor portion according to the first embodiment of the present invention;

FIG. 4 is an enlarged cross-sectional view (between bb ′) of the TFT resistor portion according to the first embodiment of the present invention;

FIG. 5 is an equivalent circuit diagram of a second embodiment of the present invention.

FIG. 6 is an enlarged view of a TFT resistor portion according to a second embodiment of the present invention.

FIG. 7 is an enlarged cross-sectional view (between aa ′) of a TFT resistor portion according to a second embodiment of the present invention;

FIG. 8 is an enlarged cross-sectional view (between bb ′) of a TFT resistor portion according to a second embodiment of the present invention.

FIG. 9 is an equivalent circuit diagram of the third embodiment of the present invention.

FIG. 10 is an equivalent circuit diagram of a fourth embodiment of the present invention.

FIG. 11 is an equivalent circuit diagram of a fifth embodiment of the present invention.

FIG. 12 is an equivalent circuit diagram of a sixth embodiment of the present invention.

FIG. 13 is an equivalent circuit diagram of a seventh embodiment of the present invention.

FIG. 14 is an equivalent circuit diagram of the eighth embodiment of the present invention.

FIG. 15 is an equivalent circuit diagram of a ninth embodiment of the present invention.

FIG. 16 is an equivalent circuit diagram of a tenth embodiment of the present invention.

FIG. 17 is an equivalent circuit diagram of an eleventh embodiment of the present invention.

FIG. 18 is an equivalent circuit diagram of a twelfth embodiment of the present invention.

FIG. 19 is an equivalent circuit diagram of a thirteenth embodiment of the present invention.

FIG. 20 is an equivalent circuit diagram of a conventional example.

FIG. 21 is an equivalent circuit diagram of a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Insulated transparent substrate, 2 ... Address wiring, 3 ... Data wiring, 4 ... Thin film transistor, 5 ... Pixel electrode, 10 ... Resistance, 11, 12 ... Thin film transistor, 13 ... Short circuit line, 1
4: Oblique film.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G02F 1/1345 G02F 1/1368

Claims (1)

(57) [Claims] 1. An insulated transparent substrate, a plurality of address lines formed in a display area on the insulated transparent substrate, a plurality of data lines formed so as to intersect with the address lines, and the address lines and the data lines. And a thin film transistor having a gate electrode electrically connected to an address wiring and a drain electrode electrically connected to a data wiring, and a source electrode of the thin film transistor formed near each of the intersections. A liquid crystal display device comprising: a connected pixel electrode; and a short-circuit line that short-circuits the address wiring and the data wiring to each other via a resistor in a region other than the display region on the insulating transparent substrate. These oblique light films are composed of thin film transistors covered with a film, and these oblique light films are all other oblique light films, the address wirings, and the data lines. The liquid crystal display device characterized by being short-circuited to at least one of the wiring or the short-circuit line.