JP2000131710A - Thin film transistor circuit substrate and liquid crystal panel using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin film transistor circuit substrate securing sufficient capacity and a liquid crystal panel using it. SOLUTION: This thin film transistor circuit substrate is provided with a common electrode 11 directly or indirectly formed on a transparent substrate, a transparent electrode 2 arranged on the common electrode 11 through a first insulation layer and electrically connected to the common electrode 11, a pixel electrode 1 formed on an opposite side position to the common electrode 11 for the transparent electrode 2 through a second insulation layer and a thin film transistor 10 electrically connected to the pixel electrode 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention also relates to a thin film transistor circuit substrate formed on a quartz substrate or a glass substrate and a liquid crystal panel using the same.

[0002]

2. Description of the Related Art In recent years, liquid crystal panels have been used as flat panel displays in notebook computers, navigation, video cameras, and the like, and as light valves in projectors, and have been commercialized. In notebook computers, high-speed processing and large-capacity CPUs have progressed, and the amount of information has dramatically increased. At the same time, the liquid crystal panel as a man-machine interface has a large screen, high resolution,
High definition display is required. Usually, an active matrix type liquid crystal panel is mainly used for such a liquid crystal panel.

In an active matrix type liquid crystal panel, each pixel is provided with a thin film transistor (hereinafter referred to as a TFT) as a switching element, and each pixel is displayed by selectively turning on and off the TFT by a source signal line and a gate signal line. . These signal lines and switching elements are formed by repeating thin film formation, selective etching, and the like on a glass substrate. Conventionally, this TFT has been formed of an amorphous silicon transistor (hereinafter referred to as a-Si). a-Si has low mobility and needs a certain size in order to secure sufficient performance for driving a pixel as a transistor. In addition, the performance is insufficient to form a drive circuit for driving the source or gate signal line, and the signal line is driven by an external circuit.

On the other hand, a polysilicon transistor (hereinafter referred to as p-
In the case of (Si), the performance as a semiconductor is high.
Pixels can be driven by a small-sized TFT. Further, part of the signal line driver circuit can be formed over the same substrate by the same process and incorporated. In particular, in recent years, p-Si formation technology using a low-temperature process has been developed, and p-Si
Since Si can be formed, great expectations are placed on cost reduction and power consumption reduction.

In an active matrix type liquid crystal panel,
In order to hold the applied voltage written through the data line until the next writing time, it is necessary to build a capacitor in parallel with the liquid crystal. Assuming that the writing cycle of the panel is 60 Hz, the holding time is 16.7 ms. The time constant determined from the resistance and the dielectric constant of the liquid crystal is not always sufficiently large with respect to this value.

A method of forming a capacitor connected in parallel to a liquid crystal includes:
There are two types, an additional capacity method and a storage capacity method. Panels currently mass-produced are often provided with an additional capacitance method because of a simple process, but will shift to a storage capacitance method in the future in order to suppress an increase in gate line capacitance and increase the aperture ratio.

FIG. 13 shows the additional capacity method. Reference numeral 131 denotes a data line to which a signal such as a video signal is constantly applied;
2 is a gate line to which a pulse signal is applied, 133 is an amorphous silicon transistor, 134 is a pixel electrode,
135 is an additional capacity. The additional capacitance 135 overlaps the adjacent gate line 132 and the pixel electrode 134 to form a capacitance. Since the capacitance can be formed only by changing the pattern of the gate line 132, there is no need to change the process. The difficulty is that the aperture ratio of the pixel decreases and the wiring capacitance of the gate line 132 increases. When the wiring capacitance increases, the load at the time of gate drive increases, and the gate line delay increases.

Next, FIG. 14 shows a storage capacity method. 141
Is a data line to which signals such as video signals are always applied,
142 is a gate line to which a pulse signal is applied;
Denotes an amorphous silicon transistor, 144 denotes a pixel electrode, and 145 denotes a storage capacitor. The storage capacitor 145 draws out a counter electrode of the capacitor as a terminal different from the gate line 142. There are two methods, a method of forming the storage capacitor forming electrode with the same material as the gate electrode and a method of forming the electrode with the transparent electrode. In any case, an increase in the capacitance of the gate line 141 is suppressed, and the aperture ratio of the storage capacitor 145 can be increased. However, since the wiring intersection is doubled as compared with the additional capacitance method, it becomes difficult in terms of yield. In order to avoid an increase in gate line capacitance, it is suitable to first form a storage capacitor forming electrode using the same material as the gate electrode. This method can be made in a process similar to the additional capacity method. The terminal for the storage capacitor needs to be drawn separately from the gate line 142, but the gate line capacitance does not increase. It is also suitable for reducing the driver voltage for converting the voltage applied to the common electrode into AC. In order to further increase the aperture ratio, the trend has been shifted to the direction of forming storage capacitors with transparent electrodes. However, the process becomes complicated. For this reason, it is difficult to use the panel unless the yield of the panel is considerably increased.

[0009]

However, recent liquid crystal panels are required to have high definition and high luminance, and the pixel pitch must be reduced while the pixel aperture ratio must be increased.
p-S with smaller transistor size than a-Si
i is more advantageous for increasing the aperture ratio. Furthermore, a smaller pattern rule is advantageous in increasing the aperture ratio because the signal line can be made thinner, or the alignment margin can be reduced because the alignment accuracy of each layer is increased.

In particular, in recent years, liquid crystal panels used for projectors have recently become increasingly smaller in panel area, higher in resolution, and extremely small in pixel pitch. In order to obtain a high light output, a liquid crystal panel having a high aperture ratio is required, and a liquid crystal panel having a TFT formed of p-Si is mainly used. However, in the case of driving with a TFT, if the capacity of the pixel is small, the applied voltage is not held for one field time, and a problem occurs that a sufficient voltage is not applied to the liquid crystal. In the case of TN (Twisted Nematic) liquid crystal, NW (Normal)
In the y White (normally white) mode, if a sufficient voltage is not applied to the liquid crystal, black does not sink and no contrast is obtained. In the case of a polymer-dispersed liquid crystal, the transmittance does not increase and the image becomes dark.

As described above, in the liquid crystal panel, the capacitance of the pixel is the capacitance of the liquid crystal itself, and the capacitance between the pixel electrode and the source signal line or the gate signal line, which is the auxiliary capacitance. However, when the pixel size is reduced, it is no longer possible to secure a sufficient capacity with these methods.

In the polymer dispersed liquid crystal panel, the thickness of the liquid crystal layer may be set to 10 μm or more in order to obtain high scattering characteristics, and the capacity of the liquid crystal itself becomes extremely small. There is a problem that can not be secured.

According to the present invention, the conventional method of taking the capacity of the pixel of the liquid crystal panel by the capacity of the liquid crystal itself and the auxiliary capacity takes into consideration the problem that a sufficient capacity cannot be secured if the pixel size is reduced. It is an object of the present invention to provide a thin film transistor circuit board that can be secured and a liquid crystal panel using the same.

[0014]

In order to solve the above-mentioned problems, a first aspect of the present invention (corresponding to claim 1) includes a common electrode formed directly or indirectly on a transparent substrate and the common electrode. A first transparent conductive thin-film electrode disposed on the electrode via a first insulating layer and electrically connected to the common electrode; and a second transparent conductive thin-film electrode with respect to the first transparent conductive thin-film electrode.
A second transparent conductive thin-film electrode formed at a position opposite to the common electrode via the insulating layer, and a thin-film transistor electrically connected to the second transparent conductive thin-film electrode. A thin film transistor circuit board characterized by the following.

The second invention (corresponding to claim 2) is:
The thin film transistor circuit board according to the first invention, wherein the first transparent conductive thin film electrode is connected between adjacent pixels.

A third aspect of the present invention (corresponding to claim 3) is:
The thin film transistor according to the first invention or the second invention, wherein the first transparent conductive thin film electrode and the second transparent conductive thin film electrode have the same shape in a pixel region and are used for a liquid crystal panel. It is a circuit board.

The fourth invention (corresponding to claim 4) provides:
The first transparent conductive thin-film electrode is connected between adjacent pixels so as to cross the source signal line of the thin-film transistor,
The thin film transistor circuit board according to the third invention, which is used for a liquid crystal panel.

A fifth aspect of the present invention (corresponding to claim 5) is:
The first transparent conductive thin film electrode is connected between adjacent pixels so as to cross the gate signal line of the thin film transistor,
The thin film transistor circuit board according to the third invention, which is used for a liquid crystal panel.

A sixth aspect of the present invention (corresponding to claim 6) is:
The thin film transistor circuit board according to the first invention, wherein the first transparent conductive thin film electrode is connected between adjacent pixels, connected to the common electrode in a region other than a pixel region, and used for a liquid crystal panel. .

A seventh aspect of the present invention (corresponding to claim 7) is:
The common electrode is formed of a metal thin film that blocks light,
The thin-film transistor circuit board according to the first invention, wherein the thin-film transistor circuit board is connected to a counter electrode sandwiching a liquid crystal layer with the common electrode and used for a liquid crystal panel.

According to an eighth aspect of the present invention (corresponding to claim 8),
The thin film transistor circuit board according to the first invention, wherein the common electrode functions as a light shielding layer and / or the thickness of the second insulating layer is 200 nm or less.

According to a ninth aspect of the present invention (corresponding to claim 9),
3. The thin film transistor circuit board according to claim 1, wherein three or more elements are connected in series.

The tenth aspect of the present invention (corresponding to claim 10)
Is a liquid crystal panel used for an active matrix liquid crystal panel, wherein the thin film transistor circuit substrate according to any one of the first to ninth inventions is used for a drive circuit for driving a signal line formed on the same substrate as the liquid crystal panel. A liquid crystal panel characterized in that:

[0024]

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

The first of the thin film transistor circuit boards of the present invention
FIG. 1 shows a planar structure of the embodiment. FIG. 1 shows one pixel unit. In practice, this pixel has a structure in which a number of pixels are repeatedly formed vertically and horizontally. FIG. 2 is a cross-sectional view taken along the line AA ′ in FIG. 1 and 2, 1 is a pixel electrode,
2 is a transparent electrode, 3, 4, 5, and 6 are contact holes, 7
Is a source signal electrode, 8 is a gate signal electrode, 9 is a drain electrode, 10 is a TFT, 11 is a common electrode, 21 is a glass substrate, and 22, 23 and 24 are insulating layers.

The pixel electrode 1 is formed of a transparent conductive thin film such as ITO and serves as an electrode for applying a voltage to the liquid crystal. The transparent electrode 2 is formed below the pixel electrode 1 via the insulating layer 23. Like the pixel electrode 1, the transparent electrode 2 is also formed of a transparent conductive thin film such as ITO, and preferably has the same shape as the pixel electrode 1. However, when the auxiliary capacitance may be small, the auxiliary capacitance may not necessarily be the same shape but may be smaller than the pixel electrode 1. The pixel electrode 1 is once connected to the metal thin film via the contact hole 3, and further connected to the drain electrode 9 via the metal thin film and the contact hole 4.
It has a structure connected with. The drain electrode 9 is formed at the intersection of the source signal line 7 and the gate signal line 8 with a T
It is connected to the FT 10 and further to the source signal line 7 via the contact hole 6.

Hereinafter, a method of applying a voltage to the pixel electrode 1 will be described in terms of a circuit. A signal such as a video signal is always applied to the source signal line 7, a pulse signal is applied to the gate signal line 8, and a TFT 10 serving as a switching element is applied.
Is applied selectively. A predetermined voltage is written to the pixel electrode 1 through the drain electrode 9 and the contact holes 3 and 4. However, the voltage applied to the pixel electrode 1 decreases during a time defined by a time constant determined by the product of the resistance and the capacitance. In the case of a liquid crystal panel, an equivalent circuit as shown in FIG. 12 is conceivable. That is, the resistance 122 of the liquid crystal layer and the capacitance 1
The time constant is determined by the reference numeral 23 and the auxiliary capacitance 124 of the pixel electrode 1. The liquid crystal layer capacitance C1 and the pixel electrode auxiliary capacitance C2
Is the total capacitance, and if C1 and C2 are small, the voltage applied to the liquid crystal cannot be maintained for one field time.

Therefore, in the present invention, the transparent electrode 2 is formed, and the insulating layer 23 is formed between the transparent electrode 2 and the pixel electrode 1, and the auxiliary capacitance is formed here. When the area of the overlapping portion of the pixel electrode 1 and the transparent electrode 2 is S, the thickness of the insulating layer 23 is t, and the unit capacitance of the insulating layer 23 is Co, the auxiliary capacitance is Co × S
/ T. Therefore, the area of the overlapping portion between the pixel electrode 1 and the transparent electrode 2 is increased, or the insulating layer 2
If the thickness of 3 is reduced, the auxiliary capacity increases. In the present invention, the pixel electrode 1 and the transparent electrode 2 are designed to have the same size, and the overlapping portion is designed to be maximized. However, the transparent electrode 2 is arranged so as to be inside the pixel electrode 1 even if it is not necessarily the present invention. It may be.

FIG. 2 is a sectional view of the thin film transistor circuit board according to the first embodiment of the present invention. The transparent electrode 2 is connected to the common electrode 11 through the contact hole 5. The common electrode 11 is electrically at the ground level.

Further, the common electrode 11 is made of Al, Cr, Mo,
If a metal thin film that reduces light transmittance such as Ti or blocks light is used as a light shielding layer, it is generated in a signal line or a TFT without providing a black matrix on a counter electrode as conventionally used. Light leakage due to the lateral electric field can be prevented.

FIG. 3 shows a thin film transistor circuit board according to a second embodiment of the present invention. In FIG. 3, 31 is a pixel electrode, 32 is a transparent electrode, 33, 34, and 36 are contact holes, 37 is a source signal electrode, 38 is a gate signal electrode,
39 is a drain electrode, 40 is a TFT, and 35 is a common electrode.

FIG. 5 is a sectional view taken along the line BB 'of FIG. 51 is a glass substrate, and 52, 53 and 54 are insulating layers. The pixel electrode 31 is formed of a transparent conductive thin film such as ITO and serves as an electrode for applying a voltage to the liquid crystal. The transparent electrode 32 is formed below the pixel electrode 31 via the insulating layer 53. Like the pixel electrode 31, the transparent electrode 32 is also formed of a transparent conductive thin film such as ITO, and preferably has the same shape as the pixel electrode 31. However, when the auxiliary capacitance may be small, the auxiliary capacitance may not necessarily be the same shape, but may be smaller inside the pixel electrode 31. The pixel electrode 31 is once connected to the metal thin film via the contact hole 33,
Further, the structure is such that the metal thin film is connected to the drain electrode 39 via the contact hole 34. The drain electrode 39 is connected to the TFT 40 formed at the intersection of the source signal line 37 and the gate signal line 38, and further connected to the source signal line 37 via the contact hole 36.

The transparent electrode 32 passes through a lower layer of the source signal line 37 and is connected to a transparent electrode of an adjacent pixel. Further, the transparent electrode 32 is connected to the common electrode 35 outside the pixel region. This eliminates the need for a contact hole for connecting the transparent electrode and the common electrode provided in the first embodiment, so that the aperture ratio can be further increased.

FIG. 4 shows a thin film transistor circuit board according to a third embodiment of the present invention. In FIG. 4, 41 is a pixel electrode, 42 is a transparent electrode, 43, 44, 46 are contact holes, 47 is a source signal electrode, 48 is a gate signal electrode,
49 is a drain electrode, 50 is a TFT, and 45 is a common electrode.

In the present invention, the transparent electrode 42 is connected to the gate signal line 4
7, and connected to the transparent electrode of the adjacent pixel. Further, the transparent electrode 42 is connected to the common electrode 45 outside the pixel region. This eliminates the need for a contact hole for connecting the transparent electrode and the common electrode provided in the first embodiment, so that the aperture ratio can be further increased.

Next, a fourth thin film transistor circuit according to the present invention will be described. FIG. 6 shows a planar structure of a thin film transistor circuit board according to a fourth embodiment of the present invention.

FIG. 6 shows the outermost part of the pixel area. The pixel structure in FIG. 6 is the same as the structure described in the second embodiment. Further, the common electrode and the transparent electrode are connected to each other by the metal thin film 63 and the contact holes 64 and 65 in portions other than the pixel region.

FIG. 7 is a cross-sectional view taken along the line CC 'in FIG. 71 is a glass substrate, and 72, 73 and 74 are insulating layers. The pixel electrode 61 is formed of a transparent conductive thin film such as ITO and serves as an electrode for applying a voltage to the liquid crystal. The transparent electrode 62 is formed below the pixel electrode 61 via the insulating layer 73. Like the pixel electrode 61, the transparent electrode 62 is also formed of a transparent conductive thin film such as ITO, and preferably has the same shape as the pixel electrode 61. However, when the auxiliary capacitance may be small, the auxiliary capacitance may not necessarily be the same shape but may be smaller inside the pixel electrode 61. The transparent electrode 62 passes through a lower layer of the source signal line 67 and is connected to a transparent electrode of an adjacent pixel. This eliminates the need for a contact hole for connecting the transparent electrode and the common electrode provided in the first embodiment, so that the aperture ratio can be further increased. Further, in an area other than the pixel area, the transparent electrode 62
Is the metal thin film 63 once by the contact hole 65.
, And further connected to a common electrode 66 through a contact hole 64. This allows the transparent electrode 62 to be electrically at the same ground level as the common electrode 66.

FIG. 8 shows a thin film transistor circuit board according to a fifth embodiment of the present invention.

In FIG. 8, reference numeral 83 denotes a metal thin film, 85 denotes a contact hole, 86 denotes a common electrode, and 88 denotes a transfer electrode with a counter electrode. The common electrode 86 is once connected to the metal thin film 83 through the contact hole 85, and further connected to the counter electrode at the transfer electrode 88. Since the common electrode 86 or the transparent electrode is a metal thin film having resistance, the resistance increases as the distance from the connection point increases, and there is a problem that a uniform voltage cannot be applied. In the present embodiment, a uniform voltage can be applied by providing not only one contact hole but three contact holes. Therefore, with such a configuration, the common electrode 86 is wide and the ground level can be realized uniformly over the entire surface of the substrate.

The contact hole 8 of the present embodiment is
The number of 5 is not limited to three in the above-described embodiment, but is two or more, such as four or five, and is a number such that the common electrode 86 is wide and the ground level can be realized uniformly over the entire surface of the substrate. You only have to.

FIG. 9 shows a thin film transistor circuit board according to a sixth embodiment of the present invention. 92 is a glass substrate, 93,
94 is an insulating layer. The pixel electrode 91 is formed of a transparent conductive thin film such as ITO and serves as an electrode for applying a voltage to the liquid crystal. In this case, the storage capacitor is composed of the pixel electrode 91 and the insulating layer 9.
The capacitance of only the portion overlapping with the common electrode 96 via 3 is provided. If the area of the overlapping portion is increased, the capacity increases, but the opening area decreases,
Get dark. Therefore, in the present invention, the thickness of the insulating layer 93 is set to 200
nm or less, and a sufficient capacity could be secured.

FIG. 10 shows a thin film transistor circuit board according to a seventh embodiment of the present invention. In FIG. 10, 101 is a pixel electrode, 102 is a transparent electrode, 103, 104, and 106.
Is a contact hole, 107 is a source signal electrode, 108
Is a gate signal electrode, 109 is a drain electrode, 110 is T
FT and 105 are common electrodes. The drain electrode 9 is bent in an N shape to form three TFTs.

The pixel electrode 101 is formed of a transparent conductive thin film such as ITO and serves as an electrode for applying a voltage to the liquid crystal. The transparent electrode 102 is formed below the pixel electrode 101 via an insulating layer. The transparent electrode 102 is also formed of a transparent conductive thin film such as ITO like the pixel electrode 101, and the pixel electrode 1
It is desirably the same shape as 01. However, when the auxiliary capacitance may be small, the auxiliary capacitance may not necessarily be the same shape but may be smaller inside the pixel electrode 101.
The pixel electrode 101 has a structure in which the pixel electrode 101 is once connected to a metal thin film via a contact hole 103, and further connected to the drain electrode 109 via the contact hole 104. The drain electrode 109 is connected to three TFTs 110 formed at the intersection of the source signal line 107 and the gate signal line 108 and at the intersection of the drain electrode 109 and the gate electrode 108, and further through the contact hole 106. 107.

By arranging three TFTs in series in this way, the W / L of the transistor can be made three times larger than that of one transistor. This increases the mobility of the transistor and makes it easier to supply current to the pixel electrode.

Note that the thin film transistor of the present invention is not limited to one in which three are connected in series as in the above-described embodiment, but in other words, three or more are connected in series, for example, four or five are connected in series. What is necessary is just to connect to.

FIG. 11 shows a liquid crystal panel according to an eighth embodiment of the present invention. In this embodiment mode, a liquid crystal panel using the thin film transistor circuit board described above will be described. In the present invention, a liquid crystal panel having a configuration in which a polymer-dispersed liquid crystal is sandwiched between two electrode substrates will be described as an example. FIG. 11 is a sectional view of the liquid crystal panel of the present invention. As the thin film transistor circuit substrate, the same substrate as that described in Embodiment Mode 2 is used. The liquid crystal layer 111 is a polymer dispersed liquid crystal, 112 is a counter substrate, and 113 is a counter electrode. The common electrode 35 and the transparent electrode 32 are connected to the counter electrode 113 by a transfer electrode (omitted) in the same manner as in the fifth embodiment, and are grounded to the ground level.

In the polymer-dispersed liquid crystal, it is necessary to increase the thickness of the liquid crystal layer in order to sufficiently secure the scattering characteristics, whereby the capacity of the liquid crystal layer is reduced, and a large auxiliary capacitance is required to hold the voltage. become.

Also in the liquid crystal projection device using this liquid crystal panel, the size of the set can be reduced because the panel size is small, and a projection device with excellent portability can be realized.

Note that the TFT of the present embodiment is the thin film transistor of the present invention, and the pixel electrode of the present embodiment is an example of the second transparent conductive thin film electrode of the present invention. The electrode is an example of the first transparent conductive thin film electrode of the present invention.

Further, the present embodiment is not limited to polysilicon, but may be amorphous silicon or single crystal silicon used for a reflection type liquid crystal panel.

Further, the transparent substrate of the present invention is not limited to the glass substrate in the above-described embodiment, but may be a transparent insulating substrate such as a silicon substrate or a quartz substrate.

Further, the liquid crystal panel of the present invention is not limited to the one using the thin film transistor circuit board of the second embodiment described above, but may use the thin film transistor circuit board of any one of the first to tenth embodiments. It is.

Furthermore, the common electrode of the present invention is not limited to the one formed directly on the glass substrate in the above-described embodiment, but is formed indirectly on the glass substrate via an intermediate layer. It only needs to be directly or indirectly formed on the substrate.

Further, the first transparent conductive thin-film electrode of the present invention crosses the source signal electrode and is connected between adjacent pixels in the above-described embodiment, or crosses the gate signal electrode and is connected between adjacent pixels. In other words, it is only necessary that the connection is made between adjacent pixels, for example, the connection is made between adjacent pixels by crossing the source signal line and also crossing the gate signal line.

[0056]

As is apparent from the above description, the present invention provides a thin film transistor circuit board and a liquid crystal panel which can secure a sufficient capacity without reducing the pixel aperture ratio even if the pixel size is reduced. can do.

[Brief description of the drawings]

FIG. 1 is a plan view of a thin film transistor circuit board according to a first embodiment of the present invention.

FIG. 2 is a sectional configuration diagram of a thin film transistor circuit board according to a first embodiment of the present invention.

FIG. 3 is a plan view of a thin film transistor circuit board according to a second embodiment of the present invention.

FIG. 4 is a plan view of a thin film transistor circuit board according to a third embodiment of the present invention.

FIG. 5 is a sectional configuration diagram of a thin film transistor circuit board according to a second embodiment of the present invention.

FIG. 6 is a plan view of a thin film transistor circuit board according to a fourth embodiment of the present invention.

FIG. 7 is a cross-sectional configuration diagram of a thin film transistor circuit board according to a fourth embodiment of the present invention.

FIG. 8 is a cross-sectional view of a thin film transistor circuit board according to a fifth embodiment of the present invention.

FIG. 9 is a plan view of a thin film transistor circuit board according to a sixth embodiment of the present invention.

FIG. 10 is a plan view of a thin film transistor circuit board according to a seventh embodiment of the present invention.

FIG. 11 is a sectional view showing the configuration of a liquid crystal panel according to an eighth embodiment of the present invention.

FIG. 12 is a circuit diagram illustrating an equivalent circuit of the liquid crystal panel according to the first embodiment of the present invention.

FIG. 13 is a plan view of a pixel portion of a liquid crystal panel in which an auxiliary capacitance is formed by a conventional additional capacitance method.

FIG. 14 is a plan view of a pixel portion of a liquid crystal panel in which an auxiliary capacitance is formed by a conventional storage capacitance method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pixel electrode 2 Transparent conductive thin film 3, 4, 5, 6 Contact hole 7 Source signal electrode 8 Gate signal electrode 9 Drain electrode 10 TFT 11 Common electrode

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 2H092 JA25 JA29 JA38 JA42 JA44 JB13 JB23 JB32 JB33 JB51 JB56 JB63 JB69 KA04 KA07 KB04 KB14 NA24 NA25 QA07 5C094 AA06 AA25 BA03 BA43 DA09 DA14 EA05 EA07 GA10 GG10 GG10 NN44 NN46 NN47 NN73

Claims (10)

[Claims] 1. A common electrode formed directly or indirectly on a transparent substrate, and disposed on the common electrode via a first insulating layer and electrically connected to the common electrode. A first transparent conductive thin-film electrode, a second transparent conductive thin-film electrode formed at a position opposite to the common electrode via a second insulating layer with respect to the first transparent conductive thin-film electrode; A thin film transistor circuit board, comprising: a thin film transistor electrically connected to the second transparent conductive thin film electrode. 2. The thin film transistor circuit board according to claim 1, wherein the first transparent conductive thin film electrode is connected between adjacent pixels. 3. The first transparent conductive thin-film electrode and the second transparent conductive thin-film electrode.
3. The thin film transistor circuit board according to claim 1, wherein the transparent conductive thin film electrode has the same shape in a pixel region and is used for a liquid crystal panel. 4. The thin film transistor circuit according to claim 3, wherein the first transparent conductive thin film electrode is connected between adjacent pixels so as to cross a source signal line of the thin film transistor, and is used for a liquid crystal panel. substrate. 5. The thin film transistor circuit according to claim 3, wherein the first transparent conductive thin film electrode is connected between adjacent pixels so as to cross a gate signal line of the thin film transistor, and is used for a liquid crystal panel. substrate. 6. The liquid crystal panel according to claim 1, wherein the first transparent conductive thin film electrode is connected between adjacent pixels, connected to the common electrode in a region other than a pixel region, and used for a liquid crystal panel.
A thin film transistor circuit board as described in the above. 7. The liquid crystal panel according to claim 1, wherein the common electrode is formed of a metal thin film that shields light, is connected to a counter electrode sandwiching a liquid crystal layer with the common electrode, and is used for a liquid crystal panel. Thin film transistor circuit board. 8. The thin film transistor circuit board according to claim 1, wherein the common electrode functions as a light shielding layer, and / or the second insulating layer has a thickness of 200 nm or less. 9. The thin film transistor circuit board according to claim 1, wherein three or more thin film transistors are connected in series. 10. A driving circuit for driving a signal line formed on the same substrate as a liquid crystal panel, the liquid crystal panel being used for an active matrix liquid crystal panel.
A liquid crystal panel using the thin film transistor circuit board according to any one of the above.