JPH10268348A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correct luminance unevenness below a permissible limit and to obtain a uniform display by providing a capacitor which is variable in capacity outside a display area on the signal input side of each gate bus line of the liquid crystal display device. SOLUTION: The capacitor 20 which is variable in capacity is formed outside the display area 18 on the signal input side of each gate bus line 14 of a liquid crystal display panel. If there is linear luminance unevenness parallel to the gate bus line 14, the capacity of the capacitor 20 is made small and the rounding of a gate signal is controlled to correct the luminance unevenness in the display area 18 below the permissible limit. Namely, variance among voltages applied to liquid crystal display elements 13 by the gate bus lines 14 due to variance in characteristics of switching elements 12 and 13 and an auxiliary capacitor 19 due to surface unevenness of polysilicon and variation in crystal characteristics are compensated by varying the capacity of the variable capacitor 20 and controlling field voltages of TFTs 12 by the gate bus lines 14 so that a voltage (drain voltage) applied to the liquid crystal display element 13 becomes uniform in a plane.

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 device, and more particularly to an active matrix type liquid crystal display device useful for reducing display defects such as uneven brightness.

[0002]

2. Description of the Related Art A liquid crystal display device has features such as small size, light weight, thin thickness, and low power consumption. Therefore, a display device of an OA device such as a personal computer, a monitor, or a display device of an AV device such as a video device. As a direct-view display device and a projection display device. In particular, an active matrix type liquid crystal display device using a thin film transistor (hereinafter referred to as a TFT) for each picture element electrode is expected to have a large screen and high definition display.

FIG. 6 shows an equivalent circuit diagram of a conventional active matrix type liquid crystal display device. In the figure, 11 is a liquid crystal display panel, and 12 is TF as a switching element.
T and 13 are liquid crystal display elements formed between the picture element electrode and the counter electrode, and together with the TFT 12, constitute one pixel.
The pair of the TFT 12 and the liquid crystal display element 13 has several hundreds.
Pieces × several hundred pieces are arranged in a grid in the row and column directions,
The liquid crystal display panel 11 is configured. Reference numeral 14 denotes a scanning line (hereinafter, referred to as a gate bus line) connected to the gate of each TFT, 15 denotes a signal line (hereinafter, referred to as a source bus line) connected to the source of each TFT, and 16 denotes a gate bus line. A scanning line driving circuit for sequentially supplying a square wave gate signal (scanning signal) to 14; a sample and hold circuit 17 for sampling and holding an external video signal; and an output of the sample and hold circuit for each source bus This is a signal line driving circuit that supplies a signal to the line 15. 18
Is a display area in which many liquid crystal display elements 13 are arranged. Reference numeral 19 denotes an auxiliary capacitor, which may or may not be provided, but is usually provided for improving display characteristics. The liquid crystal display element 13
And a circle at one end of the auxiliary capacitance 19 indicates the counter electrode potential.

Heretofore, TFTs have been formed of switching elements using amorphous silicon as a semiconductor material. In this case, since the amorphous silicon layer is collectively formed on the entire surface of the substrate by the CVD device, the uniformity of the film thickness and characteristics on the substrate is relatively good.

On the other hand, when a TFT using polysilicon having good driving characteristics as a semiconductor material is used for a switching element,
In order to manufacture a large substrate at low cost, a glass substrate is generally used, and an amorphous silicon film deposited on the glass substrate by a plasma CVD method is converted into polysilicon by a laser annealing method. in this case,
As a laser, a high-output excimer laser is used. The laser is shaped into a linear beam through an optical system, the output is made uniform, and the substrate is scanned to convert the entire surface into polysilicon. When an excimer laser is used to anneal the entire surface of a large-sized substrate, the excimer laser is a pulse laser, so that energy variations at each laser irradiation and joints between irradiations occur. For this reason, along the scanning direction of the laser, surface irregularities of the polysilicon and changes in crystal characteristics occur, which change the element characteristics of the switching element and the storage capacitor, and a line along the laser scanning direction on the display screen. Appears as uneven brightness.

[0006] Improvements in the laser annealing method have been proposed in, for example, JP-A-8-51074 and JP-A-8-51077. JP-A-8-51074 relates to a profile of a laser beam, which has a constant energy intensity distribution required for crystallization in a long axis direction and a constant energy intensity distribution and a beam required for crystallization in a short axis direction. An amorphous silicon is irradiated with a sheet-like laser beam having an energy intensity distribution that is smaller than the energy required for the crystallization and gradually changes in intensity in a region preceding the scanning direction. Further, Japanese Unexamined Patent Publication No.
Japanese Patent Application Laid-Open No. 51077 discloses a technique in which a semiconductor film in a laser light irradiation region is heated and dehydrated before laser beam irradiation. Although these techniques have improved the uniformity, sudden abnormal irradiation (due to abnormal fluctuations in irradiation energy, abnormal fluctuations in scanning speed, etc.) may occur with a low probability. Appears as uneven brightness.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of these circumstances.
It is an object of the present invention to provide a liquid crystal display device capable of correcting luminance unevenness to be equal to or less than an allowable limit when linear luminance unevenness is confirmed.

[0008]

SUMMARY OF THE INVENTION The present invention corrects luminance unevenness to below an allowable limit by providing a capacitor having a variable capacitance outside a display area on the signal input side of each gate bus line of a liquid crystal display device. be able to. Note that one end of this capacitor is preferably connected to a stable potential such as a counter electrode potential or a ground potential. Further, the capacitor may be formed on an active matrix substrate, or may be formed in combination with a counter electrode on a counter substrate which is bonded to form a liquid crystal display element. Further, it is preferable to use a capacitor whose capacity can be changed by laser irradiation after the liquid crystal display device is formed. The means for varying the capacity is not limited to laser trimming and laser heating, but may use an electric field, a magnetic field, an optical means, a mechanical means, or the like.

More specifically, the liquid crystal display device of the present invention includes a scanning line and a signal line wired in a grid on an insulating substrate, and a picture element region surrounded by the scanning line and the signal line. An active matrix substrate having a picture element electrode and a switching element connected to the picture element electrode, and a liquid crystal display panel having a liquid crystal material interposed between a counter substrate having a counter electrode facing the picture element electrode, It is characterized by having a condenser capable of changing the capacitance for each scanning line.

The liquid crystal display device according to the present invention is characterized in that the capacitor is formed on an active matrix substrate.

Further, in the liquid crystal display device according to the present invention, one electrode of the capacitor is formed on an active matrix substrate, and the other electrode is formed using a part of the counter electrode on the counter substrate. And

Further, in the liquid crystal display device according to the present invention, the capacitance of the capacitor is adjusted by irradiating a laser from outside the liquid crystal display panel.

Further, in the liquid crystal display device according to the present invention, at least a channel portion of the switching element is formed of polycrystalline silicon.

The present invention has the above features,
By providing a capacitor whose capacitance can be changed outside the display area on the signal input side of each gate bus line of the liquid crystal display panel, characteristic variations of switching elements and auxiliary capacitance due to surface irregularities of polysilicon and changes in crystal characteristics Of the voltage applied to the liquid crystal display element for each gate bus line by changing the capacitance of the variable capacitor provided in each gate bus line to control the fall region of the gate signal, thereby providing a TFT feedthrough. The voltage can be controlled for each gate bus line, and the voltage (drain voltage) applied to the liquid crystal display element can be compensated so as to be uniform in the plane.

[0015] In more detail about the feed-through voltage, when the gate signal voltage V _G as shown in FIG. 5 rises ON voltage from the OFF voltage, the source bus line 15
Through TFT12 from the video signal voltage V _S is started charging a liquid crystal display device 13 and the auxiliary capacitor 19, the drain voltage V _D rises to the source voltage V _S. After charging time is over,
Gate voltage V _G falls from the ON voltage to the OFF voltage. In this case, the capacitance C _LC of the liquid crystal display element 13, the capacitance C _S of the auxiliary capacitance 19, the parasitic capacitance C _GD between the gate electrode and the drain electrode of the TFT 12, the ON voltage and OFF of the gate signal.
When the difference between voltage and [Delta] V _G, by capacitive coupling, the drain voltage is lowered. This voltage is called a feed-through voltage [Delta] V a _{ΔV = C GD / (C LC} + C S + C GD) * is expressed by [Delta] V _G.

Due to variations in the irradiation energy of the laser irradiation, fluctuations in the scanning speed, and the seams between the irradiations, the surface irregularities and crystallinity of the polysilicon change, which is caused by the parasitic capacitance C between the gate electrode and the drain electrode of the TFT. variation of _GD, capacitance C _LC variations in the auxiliary capacitance, become the variations in the device characteristics of the TFT such as, as a result, a feed-through voltage Δ
V varies, resulting in uneven display luminance.

However, if the fall of the gate signal is large, the recharge current flows in a direction to compensate the feedthrough voltage from the source electrode to the drain electrode during the change of the gate voltage, so that the drain voltage increases. . FIG.
The solid line indicates the case where the rounding of the gate signal is small, the feed-slur voltage ΔV _{1 at} this time, and the broken line indicates the case where the rounding of the gate signal is large. At this time, if the feed-slur voltage ΔV ₂ , ΔV ₁ > ΔV ₂ Becomes

Therefore, by controlling the rounding of the gate signal, the feedthrough voltage ΔV can be controlled, and the uniformity of the drain voltage can be improved. In the present invention, the control of the rounding of the gate signal is realized by providing a variable capacitance capacitor on the input side of each gate line and adjusting the capacitance.

[0019]

Next, the present invention will be described in more detail with reference to examples.

(Embodiment 1) FIG. 1 is an equivalent circuit diagram of an active matrix type liquid crystal display device according to an embodiment of the present invention. The same reference numerals are given to portions corresponding to those in FIG. 6, and detailed description thereof will be omitted. . A large number of gate bus lines 14 are arranged in parallel with each other in the direction of the horizontal axis, about several hundreds. The source bus lines 15 are stacked in a direction orthogonal to the gate bus lines 14 at each intersection via an insulating layer. A large number of books are arranged in parallel. Therefore, the gate bus line 14 and the source bus line 15 are insulated,
They are arranged in a grid in the row and column directions. A TFT 12 as a switching element, a liquid crystal display element 13 and an auxiliary capacitance 19 are formed in a picture element region surrounded by both bus lines. The gate of the TFT 12 is connected to a gate bus line 14, the source is connected to a source bus line 15, and the drain is a liquid crystal display element 13 and an auxiliary capacitor 19.
It is connected to the. The liquid crystal display element 13 is formed between the pixel electrode and the counter electrode, and the storage capacitor 19 is formed between the pixel electrode and the storage capacitor electrode, and is connected to the counter electrode through a storage capacitor line. The opposite electrode is preferably connected to a stable potential such as a ground potential, but may be an AC drive in which the polarity is inverted for each field of the video signal. The method of this embodiment is Cs on Common, but Cs on Common.
Gate method may be used. A feature of the embodiment of the present invention is that each gate bus line has a variable capacity capacitor 20.
Is formed.

Next, based on the plan view of FIG. 2A and the cross-sectional view of FIG. 2B, the structure of the main part of the liquid crystal display device of the present invention will be described. On the glass substrate 21, a base coat 2 such as a SiO ₂ film is formed for the purpose of preventing impurity components such as alkali in the glass from diffusing into the semiconductor layer and the liquid crystal layer.
2 is formed. Subsequently, an amorphous silicon film is formed thereon by a low pressure CVD method or a plasma CVD method. When an amorphous silicon film is formed by a plasma CVD method, heat treatment is performed at a temperature of about 450 ° C. for several hours to release hydrogen in the film and prevent film peeling during laser irradiation.

After that, annealing is performed with an excimer laser to convert the entire surface into polysilicon. If the laser beam is substantially the same as or longer than the gate bus line 14 of at least one display area 18, for example, a linear laser beam having a length of 150 mm and a width of 1 mm, The beam is scanned in the direction of the source bus line to convert the entire surface into polysilicon. When the laser beam is a rectangle having a length of several mm to several tens mm and a width of 1 mm, scanning is performed in a direction perpendicular to the longitudinal direction of the rectangular laser beam. Scanning is performed with the scanning direction set to the same direction as the gate bus line. Then, such scanning is repeated while moving in the vertical axis direction (source bus line direction).

Thereafter, the TFT is formed by photolithography.
Of the TFT and the drain region 40 of the TFT in the subsequent steps are left in an island shape, and SiO _{2 is} formed as the gate insulating film 23 on the entire surface thereof.
A film is formed. A plurality of gate bus lines 31 are provided thereon in parallel in the horizontal axis direction, and a gate electrode is formed at the same time. In this step, the auxiliary capacitance line 33 is connected along the gate bus line 31 with the auxiliary capacitance electrode connected thereto. 36 are provided in parallel. On the signal input side of the gate bus line 31, the capacitor lower electrode 41 is formed to be branched outside the display area. Therefore, the capacitor lower electrode 41 is formed between the display area and the seal area of the liquid crystal display panel. The gate bus line 31, the capacitor lower electrode 41, the auxiliary capacitance line 33, and the auxiliary capacitance electrode 36 are formed of an Al alloy, and their surfaces are anodized.

Next, a portion of the source region 39 and the drain region 40 of the TFT is doped with phosphorus (P) ions,
Activation annealing is performed, and n ⁺ conversion is performed. Next, an SiO ₂ film is formed on the entire surface as the interlayer insulating film 24. In the interlayer insulating film 24, contact holes are made in the TFT source region 39 and the variable capacitance capacitor connecting portion 38, and a number of source bus lines 32 are provided on the interlayer insulating film in parallel with the vertical axis direction. Connect to 39.
At the same time, a capacitor upper electrode 37 is formed on each gate bus line, and is connected to the auxiliary capacitance line 33 at a connection portion 38. The source bus line 32 and the capacitor upper electrode 37 are formed of an Al alloy. The variable capacity capacitor 20 is formed by a capacitor lower electrode 41 and a capacitor upper electrode 37, and an interlayer insulating film (SiO ₂ ) is used as an insulating film.

Thereafter, a contact hole is formed in the drain portion 40 of the TFT, and a pixel electrode 35 is formed of ITO in a region surrounded by both bus lines, and is connected to the drain region 40. Part of the picture element electrode 35 overlaps with the auxiliary capacitance electrode 36 to form an auxiliary capacitance.

Thereafter, both the active matrix substrate and the opposing substrate are coated with an alignment film and rubbed, and the spacers are evenly spread over the entire surface, the periphery is sealed with a sealant, and the substrates are bonded together. Thus, the liquid crystal display panel is completed.

Then, a video signal or a test signal is supplied to the gate bus line and the source bus line of the liquid crystal display panel to perform a display test of the liquid crystal display device, and there is linear luminance unevenness parallel to the gate bus line. The capacitor upper electrode 37 formed on the corresponding gate bus line and the adjacent gate bus line and, if necessary, the gate bus line around the gate bus line is connected to the opposite substrate side or the capacitor lower electrode 41 is connected to the active matrix substrate side. The area of the upper electrode 37 or the lower electrode 41 is made smaller by a technique such as laser trimming. The rate at which the area is reduced depends on the situation of uneven brightness. A corresponding gate bus line cuts a large area and an adjacent gate bus line cuts a smaller area. The peripheral gate bus line may be further cut to a smaller size, or may be cut at the opposite rate. Either of the methods is selected to reduce the capacitance of the capacitor, control the rounding of the gate signal, and correct the luminance unevenness in the display area of the liquid crystal display device within an allowable limit.

Although a scanning line driving circuit and a signal line driving circuit are not shown, a normal LSI is connected to the outer periphery of the liquid crystal display panel or a polysilicon TFT is used outside the display area of the active matrix substrate. Each circuit is formed.

In this embodiment, the capacitor is formed between the display area and the seal area. However, it is sufficient that the condenser is outside the display area. Therefore, the active matrix substrate in the seal area or outside the seal area is used. Can be formed.

(Embodiment 2) FIG.
However, as shown in the plan view of FIG. 3A and the cross-sectional view of FIG.
A point formed of polysilicon forming T, formed simultaneously with the TFT, doped with P ions and converted to n ⁺ , making a contact hole in the gate insulating film, connected to the auxiliary capacitance line 33, and the upper electrode of the capacitor. 37 is characterized in that it is branched from the gate bus line. In this case, the capacitor 20 is formed by the capacitor lower electrode 41 and the capacitor upper electrode 37, and the gate insulating film SiO ₂ is used as the insulating film. Therefore, the capacitor lower electrode 41 is formed between the display area and the seal area of the liquid crystal display panel.

The correction of the uneven brightness is performed by controlling the rounding of the gate signal by changing the capacity of the capacitor 20 as in the first embodiment. The capacity of the capacitor 20 can be controlled by adjusting the energy of laser irradiation to partially re-amorphize the n ⁺ polysilicon of the capacitor lower electrode 41, thereby reducing the capacity of the capacitor. Sheet resistance of n ⁺ polysilicon is 1KΩ
However, when amorphous, the resistance becomes higher than polysilicon by three orders of magnitude or more, and it does not work as a capacitor electrode, and the capacity decreases. When the polysilicon is formed again by irradiating the laser with the energy necessary for forming the polysilicon, the capacity can be increased.

Although a scanning line driving circuit and a signal line driving circuit are not shown, a normal LSI is connected to the outer periphery of the liquid crystal display panel, or a polysilicon TFT is used outside the display area of the active matrix substrate. Each circuit is formed.

In this embodiment, the capacitor is formed between the display area and the seal area. However, it is sufficient that the capacitor is provided outside the display area. Therefore, the active matrix substrate in the seal area or outside the seal area is used. Can be formed.

(Embodiment 3) A plan view of FIG.
The structure of the liquid crystal display device will be described based on the cross-sectional view of FIG. 2 (a) and 2 (b) are denoted by the same reference numerals. An SiO ₂ film is formed as a base coat 22 on the glass substrate 21 in order to prevent an alkali component in the glass from entering the semiconductor layer and the liquid crystal layer. Continuously, an amorphous silicon film is formed thereon. After that, annealing is performed with an excimer laser to convert the entire surface into polysilicon. The laser beam has a length substantially equal to or longer than the gate bus line 14 of the at least one display area 18, for example, a length of 15
In the case of a linear laser beam having a width of 0 mm and a width of 1 mm, the entire surface is converted into polysilicon by scanning the laser beam in the direction of the source bus line. When the laser beam is a rectangle having a length of several mm to several tens mm and a width of 1 mm, scanning is performed in a direction perpendicular to the longitudinal direction of the rectangular laser beam. Scanning is performed with the scanning direction set to the same direction as the gate bus line. Then, such scanning is repeated while moving in the vertical axis direction (source bus line direction).

Thereafter, the TFT is formed by photolithography.
The channel region 34 and the portions to be the source region 39 of the TFT and the drain region 40 of the TFT in the subsequent steps are left in an island shape, and an SiO ₂ film is formed as the gate insulating film 23 on the entire surface thereof. On top of that, the gate bus line 3
A large number 1 is provided in parallel in the horizontal axis direction, and an auxiliary capacitance line 33 and an auxiliary capacitance electrode 36 connected thereto are provided in parallel along the gate bus line 31. Gate bus line 3
The capacitor lower electrode 41 is formed to be branched outside the display area on the signal input side of the first. Therefore, the capacitor lower electrode 41 is formed between the display area and the seal area of the liquid crystal display panel. The gate bus line 31, the capacitor lower electrode 41, the auxiliary capacitance line 33, and the auxiliary capacitance electrode are formed of an Al alloy, and the surfaces thereof are anodized.

Next, P ion is doped into the source region 39 and the drain region 40 of the TFT, activation annealing is performed, and n ^{+ is} formed. Next, an SiO ₂ film is formed on the entire surface as the interlayer insulating film 24. A contact hole is formed in the source region 39 of the TFT, and the source bus line 32 is formed.
Are provided in the direction of the vertical axis, and are connected to the source region 39 of the TFT. Here, the source bus line 32 is formed of an Al alloy. A contact hole is formed in the drain region 40 of the TFT, a picture element electrode 35 is formed of ITO, and connected to the drain region 40. On the other hand, a counter substrate 26 in which a counter electrode 29 is formed on a glass substrate 30 is manufactured. Thereafter, both the active matrix substrate 25 and the opposing substrate 26 are coated with an alignment film 27 and rubbed, and the spacers are evenly spread over the entire surface, the periphery is sealed with a sealant, and the liquid crystal 28 is injected therebetween. Thus, a liquid crystal display device is completed. The variable capacity capacitor 20 is formed by a capacitor lower electrode 41 and a counter electrode 29, and an insulating film is an interlayer insulating film (SiO ₂ ) 27, a liquid crystal 28, or the like.

Then, a video signal or a test signal is supplied to the gate bus line and the source bus line of the liquid crystal display panel to perform a display test of the liquid crystal display device, and there is a linear luminance unevenness parallel to the gate bus line. The area of the capacitor lower electrode 41 formed on the corresponding gate bus line and the adjacent gate bus line and, if necessary, the peripheral gate bus line is reduced from the active matrix substrate side by a technique such as laser trimming. . The rate at which the area is reduced depends on the situation of uneven brightness. A corresponding gate bus line cuts a large area and an adjacent gate bus line cuts a smaller area. The peripheral gate bus line may be further cut to a smaller size, or may be cut at the opposite rate. Either of the methods is selected to reduce the capacitance of the capacitor, control the rounding of the gate signal, and correct the luminance unevenness in the display area of the liquid crystal display device within an allowable limit.

Although a scanning line driving circuit and a signal line driving circuit are not shown, a normal LSI is connected to the outer periphery of the liquid crystal display panel or a polysilicon TFT is used outside the display area of the active matrix substrate. Each circuit is formed.

(Evaluation) The results of evaluation of the degree to which the display brightness unevenness is improved by the above embodiment are shown below.

[0040]

[Table 1]

In the display test, the gate signal ON voltage was 10 V,
The luminance unevenness in the display area when the halftone display was performed with an OFF voltage of −10 V, a source voltage of ± 3.5 V, and a counter voltage of −1 V was measured. As shown in Table 1, it was confirmed that the luminance unevenness can be reduced by the correction. In addition, the correction was performed so that the place where the luminance was greatly shifted was inconspicuous,
It is considered that the more uniform the correction is, the more uniform it becomes. In addition, the luminance unevenness of the backlight itself was corrected.

In the initial characteristics of the embodiment, the luminance unevenness is reduced as compared with the prior art, and it can be seen that there is an effect of reducing the luminance unevenness by giving a large rounding to the fall of the gate signal. This is considered to be a strong function of compensating the feedthrough voltage, and to reduce variations in pixel voltage.

[0043]

As described above, according to the present invention, by providing a capacitor whose capacity can be varied outside the display area on the signal input side of each gate bus line of the liquid crystal display device, uneven brightness can be reduced to an allowable limit or less. This makes it possible to produce a liquid crystal display device that can provide uniform display with good yield. Further, even without correction, the function of compensating the feed-through voltage works strongly, and the variation of the pixel voltage is reduced, so that there is also an effect of reducing the luminance unevenness.

[Brief description of the drawings]

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

FIGS. 2A and 2B show a main part of a liquid crystal display panel according to a first embodiment of the present invention, wherein FIG. 2A is a plan view and FIG.

3A and 3B show a main part of a liquid crystal display panel according to a second embodiment of the present invention, wherein FIG. 3A is a plan view and FIG.

4A and 4B show a main part of a liquid crystal display panel according to a third embodiment of the present invention, wherein FIG. 4A is a plan view and FIG.

FIG. 5 shows an explanatory diagram of a feedthrough voltage.

FIG. 6 shows an equivalent circuit diagram of a conventional liquid crystal display device.

[Explanation of symbols]

 Reference Signs List 11 liquid crystal display panel 12 TFT 13 liquid crystal display element 14 scanning line (gate bus line) 15 signal line (source bus line) 16 scanning line driving circuit 17 signal line driving circuit 18 display area 19 auxiliary capacity 20 capacitor 21 glass substrate 22 glass coat Reference Signs List 23 gate insulating film 24 interlayer insulating film 25 active matrix substrate 26 counter substrate 27 alignment film 28 liquid crystal 29 counter electrode 30 glass substrate 31 gate bus line 32 source bus line 33 auxiliary capacitance line 34 channel region 35 pixel electrode 36 auxiliary capacitance electrode 37 Capacitor upper electrode 38 Capacitor connection 39 Source region 40 Drain region 41 Capacitor lower electrode

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01L 21/336

Claims (5)

[Claims] 1. A scanning line and a signal line wired in a grid on an insulating substrate, and a pixel electrode and a pixel electrode in each pixel region surrounded by the scanning line and the signal line. In a liquid crystal display panel in which a liquid crystal material is interposed between an active matrix substrate having a switching element and a counter substrate having a counter electrode opposed to the picture element electrode, the liquid crystal display panel includes a capacitor capable of changing the capacitance of each scanning line. A liquid crystal display device comprising: 2. The liquid crystal display device according to claim 1, wherein said capacitor is formed on an active matrix substrate. 3. The capacitor according to claim 1, wherein one electrode of the capacitor is formed on an active matrix substrate, and the other electrode is formed using a part of a counter electrode on a counter substrate. Liquid crystal display. 4. The liquid crystal display device according to claim 1, wherein the capacitance of the condenser is adjusted by laser irradiation from outside the liquid crystal display panel. 5. The liquid crystal display device according to claim 1, wherein at least a channel portion of said switching element is formed of polycrystalline silicon.