JP2004110021A - Electro-optic apparatus and its manufacturing method, and electronic appliance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electro-optic apparatus with a built-in driving circuit in which a peripheral driving circuit for matrix driving of pixels is integrally formed on an active matrix substrate, to provide a method for manufacturing the apparatus, and an electronic appliance, and to prevent image signals during fast driving from becoming dull. <P>SOLUTION: A part of the common electrode 220 formed on a counter substrate 200 is removed where the electrode overlaps in the plan view with peripheral driving circuits 130, 170 or wiring to supply signals to the peripheral driving circuits 130, 170 on the active matrix substrate 100. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to an electro-optical device having a built-in driving circuit in which a peripheral driving circuit for driving a pixel portion in a matrix is integrally formed on an active matrix substrate, a manufacturing method thereof, and an electronic apparatus.

In a conventional electro-optical device, for example, an active matrix substrate used in a liquid crystal device, a driving circuit built-in type in which a peripheral driving circuit for driving a pixel portion, such as a scanning line driving circuit and a data line driving circuit, is formed on the substrate. Things are being developed. In this type of electro-optical device, components of a peripheral driving circuit and switching elements for driving a pixel portion are manufactured by a common process. For example, in a liquid crystal device, an element included in a peripheral driver circuit is formed simultaneously with a thin film transistor (Thin Film Transistor, hereinafter abbreviated to TFT) for driving a pixel portion. This is advantageous in reducing the size and cost of the entire device as compared with those on which a substrate is mounted.

In the above-described liquid crystal device, the active matrix substrate and the opposing substrate are bonded to each other with a fixed interval by a sealing material mixed with a spacer, and liquid crystal is sealed in a space formed by the pair of substrates and the sealing material. Structure.

The common electrode such as ITO is formed on the inner surface (liquid crystal side) of the opposing substrate over the entire surface, and the sealing material is provided in a frame shape along the outer periphery of the opposing substrate. On the other hand, on the inner surface side of the active matrix substrate, scanning lines and signal lines are formed in a matrix, and a pixel portion including a TFT and a pixel electrode is formed at the intersection. Then, a rectangular display area is formed by an area where the pixel portions are formed in a matrix.

In addition, in a peripheral portion of the display area, a scanning line driving circuit that sequentially supplies a pulsed scanning signal to each scanning line, a data line driving circuit that supplies a predetermined image signal to each signal line, and the like are provided. Peripheral driving circuit is arranged along the edge of the rectangular display area. The data line driving circuit includes a horizontal shift register for selecting a predetermined signal line, and a sample and hold circuit for supplying an image signal sampled to the selected signal line. When a predetermined scanning line and a signal line are selected, image signals are supplied to the pixel portion located at the intersection of the selected lines.
JP-A-8-248405 JP-A-11-109408

Incidentally, the above-described scanning line driving circuit and data line driving circuit are usually driven at a frequency of about several MHz, and a signal is supplied to the common electrode on the opposite substrate and the peripheral driving circuit on the active matrix substrate and the peripheral driving circuit. There is almost no problem with the parasitic capacitance formed between the wiring and the wiring for supplying the voltage. That is, even if a signal delay occurs due to such a parasitic capacitance, the delay time is sufficiently shorter than the signal writing time, so that there is little possibility that the image signal will be dull.

On the other hand, in recent years, in order to obtain a higher quality display, a peripheral drive circuit has been required to be driven at a high speed of about several tens of MHz. In this case, since the writing time is not sufficiently large compared to the delay time, the image signal may be distorted due to the above-mentioned parasitic capacitance, and the image quality may be degraded.

The present invention has been made in view of the above problems, and has as its object to provide an electro-optical device, a method of manufacturing the same, and an electronic apparatus capable of preventing image signal blunting under high-speed driving.

In order to achieve the above object, an electro-optical device according to the present invention includes a plurality of scanning lines, a plurality of signal lines provided so as to intersect the scanning lines, and an intersection between the scanning lines and the signal lines. A plurality of pixel electrodes respectively provided on the same surface, an active matrix substrate having a peripheral drive circuit for driving each of the pixels in a matrix on the same surface, a common electrode provided on one surface, and the common electrode and the pixel electrode And a liquid crystal layer sandwiched between the active matrix substrate and the counter substrate, wherein the liquid crystal layer is interposed between the active matrix substrate and the counter substrate. A portion that overlaps with a wiring for supplying a signal to the peripheral drive circuit in a plan view is removed.

According to this configuration, the occurrence of a parasitic capacitance between the peripheral drive circuit and the common electrode is prevented beforehand, and even when the peripheral drive circuit is driven at a high speed, signal rounding is reduced and a high-quality display can be obtained. In addition, since the above-described generation of the parasitic capacitance is prevented only by removing the portion of the common electrode facing the peripheral driving circuit and the like, the degree of freedom in arranging the peripheral driving circuit and the like can be increased.
In particular, the above-described effect is particularly large when the peripheral driving circuit includes a thin film transistor having a channel region made of single-crystal silicon and can be driven at a high speed of 10 MHz or more.

The peripheral drive circuit includes one of a data line drive circuit and a sample hold circuit, and the wiring includes at least one of a clock signal line, an image signal selection line, and an image signal line. It is desirable to do so.
Since the above-mentioned peripheral driving circuit is required to be driven at a particularly high speed, there is a possibility that large signal rounding may occur due to a parasitic capacitance generated between the peripheral driving circuit and the common electrode. Therefore, by preventing the common electrode from overlapping with the above-described peripheral driving circuit in a plan view, display quality can be significantly improved.

The method for manufacturing an electro-optical device according to the present invention further includes a step of forming a plurality of pixel electrodes and a peripheral driving circuit for driving the plurality of pixel electrodes in a matrix on one surface of the active matrix substrate; Forming a common electrode over the entire surface, and removing a portion of the common electrode of the counter substrate that overlaps in plan view with the peripheral drive circuit or a wiring for supplying a signal to the peripheral drive circuit, As the pixels and the common electrode face each other, bonding the active matrix substrate and the opposing substrate at a constant interval by a sealant, and the active matrix substrate, the opposing substrate and the sealant, Forming a liquid crystal layer by injecting liquid crystal into a space formed by the method.

According to the present manufacturing method, it is possible to easily prevent the occurrence of the parasitic capacitance between the peripheral drive circuit and the common electrode by only etching a part of the common electrode, and to follow the conventional manufacturing process almost as it is. .
According to another aspect of the invention, an electronic apparatus includes the above-described electro-optical device.
According to this configuration, it is possible to provide an electronic apparatus including an electro-optical device capable of displaying high-quality images with less signal distortion.

As described above in detail, according to the present invention, a portion of the common electrode formed on the counter substrate, which overlaps with the peripheral drive circuit in plan view, is removed. The occurrence of parasitic capacitance between them is prevented. As a result, even when the peripheral driving circuit is driven at a high speed, a high-quality display can be obtained with less signal rounding. In addition, since the above-described parasitic capacitance is prevented from being generated only by removing the common electrode in a portion facing the peripheral driving circuit and the like, the degree of freedom in arrangement of the peripheral driving circuit and the like can be increased.

FIG. 1 is a plan view of an active matrix substrate of a liquid crystal device as an example of the electro-optical device according to the present embodiment, as viewed from a counter substrate side together with components formed thereon, and FIG. FIG. 3 is a block diagram showing an electrical configuration of various wirings, peripheral circuits, and the like provided on the active matrix substrate.

The liquid crystal device according to the present embodiment is configured as an electro-optical device having a built-in peripheral circuit in which a peripheral drive circuit is integrally formed, and as shown in FIG. 3, a central portion of an active matrix substrate 100 made of hard glass, quartz, or the like. A rectangular display area 150 is provided in the area, and a scanning line driving circuit 120, a data line driving circuit 110, and predetermined signals such as a clock signal and an image signal are supplied to these circuits 110 and 120 around the outside of the display area 150. A peripheral drive circuit including various wirings to be supplied is provided.

Here, in the display area 150, a plurality of scanning lines 155 and signal lines 156 are formed in the X direction and the Y direction, respectively, and a TFT (thin film transistor) 152 is formed at the intersection of each scanning line 155 and signal line 156. A pixel portion including the rectangular pixel electrode 151 is formed. The gate and the source of the TFT 152 are connected to the scanning line 155 and the signal line 156, respectively, and the drain is connected to the pixel electrode 151. In addition, a storage capacitor 151a is connected to the drain in parallel with the pixel electrode 151 in order to enhance the holding characteristics.

The scanning line driving circuit 120 mainly includes a vertical shift register, and performs scanning in one vertical scanning period based on a reference clock or the like supplied from an external control device via a clock signal line (not shown). .., Gm are applied to the line 155 in a line-sequential manner.

The data line drive circuit 110 sequentially sends the sampling drive signals S1, S2,... Sn to each sampling drive signal line 111 based on a reference clock supplied from an external control device via a clock signal line (not shown). It comprises a horizontal shift register 110 to be supplied and a sample and hold circuit 130 for sampling the image signals VID1 to VID6 supplied via the image signal line 112.

The sample hold circuit 130 includes a sampling switch (TFT) 131 provided for each signal line. Each sampling switch 131 receives sampling drive signals S1, S2,..., Sn from the horizontal shift register 110. Then, the image signals VID1 to VID6 sampled for each of the six image signal lines 112 are sequentially applied to each group including six adjacent signal lines 156. Accordingly, the sampled image signal is supplied to each signal line 156 during one horizontal scanning period (that is, a period during which the scanning signal is supplied to one scanning line 155 by the scanning line driving circuit 120). It has become.

As shown in FIG. 1, a mounting terminal 140 for mounting an external control device is provided at an end on the lower side of the active matrix substrate 100. Various signals are supplied to the scanning line driving circuit 120 and the data line driving circuit 110.
Further, an alignment film (not shown) made of polyimide or the like is formed on the active matrix substrate 100 configured as described above, and a sealing material 160 is applied in a rectangular frame shape so as to surround the display region 150. .

Note that the TFTs forming each of the above-described peripheral driving circuits and the TFTs 152 forming each pixel portion of the display area 150 are manufactured by a common process. Further, in order to enhance the driving capability, single-crystal silicon is used for the channel region of the TFT, and is formed on the active matrix substrate 100 using, for example, SOI (Silicon on Insulator) technology. By using single-crystal silicon having high charge mobility in the channel region of the TFT, high-speed driving of several tens to several hundreds of MHz can be supported.

The layout of these circuits 110 and 120 is defined so that the display quality can be maximized when the size of the active matrix substrate is fixed. For example, as shown in FIG. 1, the scanning line driving circuit 120 and the horizontal register 170 of the data line driving circuit 110 in which the driving voltage includes a DC component are arranged in a region not facing the liquid crystal (that is, outside the frame of the sealing material). In addition, the liquid crystal layer 50 is prevented from being deteriorated by the DC voltage leaking into the liquid crystal layer 50 from these circuits.

In addition, the sample and hold circuit 130 that is driven by an alternating current with respect to the counter electrode potential is arranged in the frame of the seal material 160 so that the seal material 160 is arranged between the sample and hold circuit 130 and the horizontal shift register 170. Has become. By arranging in this manner, when the substrates 100 and 200 are bonded to each other, the seal material 160 is less likely to be spread in the display region 150 due to the collapse of the seal material 160, so that the seal width margin can be set small. it can. Accordingly, the size of the active matrix substrate 100 can be reduced, which is advantageous in cost. Further, since the output signal voltage of the sample and hold circuit 130 does not include a DC component with respect to the potential of the light-shielding film 210 and the common electrode 220 provided through the liquid crystal, the liquid crystal does not deteriorate due to leakage voltage from the circuit. .

On the other hand, as shown in FIGS. 1 and 2, on the inner surface side (the liquid crystal layer 50 side) of the counter substrate 200 made of glass or the like, along the outer periphery of the display region 150, Cr (chromium), Ni (nickel), A light-shielding film (peripheral parting) 210 made of a metal material such as Al (aluminum) is formed in a rectangular frame shape, and a transparent common electrode 220 made of ITO or the like is formed so as to cover the light-shielding film 210 and the substrate surface. Have been.

The light-shielding film 210 and the common electrode 220 include a data line driving circuit 110 that performs high-speed driving, an image signal line 112 that supplies various signals to the data line driving circuit 110, and a sampling driving signal line (image signal selection line). 306, a clock signal line (not shown) and the like are arranged so as not to overlap in plan view.
For example, the lower side edge of the light-shielding film 210 is disposed closer to the display area 150 than the data line driving circuit 110 and the above-described various wirings in a plan view. When the sample and hold circuit 130 is arranged closest to the display area 150, the lower edge of the light-shielding film 210 is arranged between the sample and hold circuit 130 and the display area 150 in plan view. You. On the other hand, in the common electrode 220, the electrode surface of the portion 220a overlapping the data line driving circuit 110 and the above-described various wirings in plan view is removed.

By not providing a conductive material such as the light-shielding film 210 and the common electrode 220 at a position facing the peripheral drive circuit where high-speed driving is performed, a parasitic capacitance between the conductive material and the peripheral drive circuit is eliminated. Is prevented from occurring, and a high quality display with less signal rounding can be obtained. The common electrode 220 of the opposing substrate 200 may be formed, for example, by forming a light-shielding film 210 on the opposing substrate 200, forming a transparent electrode made of ITO or the like over the entire surface of the substrate, and viewing the data line driving circuit 110 or the like in plan view. Is obtained by removing a portion overlapping with the above by etching.

This opposing substrate 200 is bonded to the active matrix substrate 100 by the above-described sealing material 160, and is held at a constant interval by a spacer (not shown) provided in the sealing material 160. Then, a space formed by the substrates 100 and 200 and the sealing material 160 is filled with a liquid crystal, and a liquid crystal layer 50 is formed. In addition, conduction between the active matrix substrate 100 and the opposing substrate 200 is achieved by the conduction agent 161 provided in at least one of the four corners of the sealing material 160.

In such a configuration, when the scanning signal Gm is supplied to a certain scanning line 155 from the external control device, first, all the TFTs 152 connected to this scanning line 155 are turned on. In parallel with this, six parallel image signals VID1 to VID6 supplied from the image signal line 112 are sampled by the sample hold circuit 130. Next, when the sampling drive signals S1, S2,..., Sn are sequentially supplied, the sampled image signals VID1 to VID6 are written into the liquid crystal layer 50 corresponding to the turned-on TFT 152, and are held for a predetermined period. You. At this time, since the orientation and order of the liquid crystal molecules change according to the voltage level applied to the liquid crystal layer 50 of each pixel, gradation display is performed by the light modulation.

Therefore, according to the electro-optical device of the present invention, the parasitic drive is required between the common electrode 220 and the peripheral drive circuit, such as the data line drive circuit 110, which is required to drive at high speed, and various wirings for supplying signals to the peripheral drive circuit. Since the generation of the capacitance can be prevented, even when such a peripheral driving circuit is driven at a high speed, signal rounding is reduced and a high quality display can be obtained. Further, since the above-described parasitic capacitance is prevented from being generated only by removing the portion of the common electrode 220 facing the peripheral driving circuit and the like, the degree of freedom in circuit arrangement can be increased.

The generation of such a parasitic capacitance can be achieved only by removing a part of the common electrode 220 formed over the entire surface of the counter substrate 200 (that is, a part overlapping with the peripheral driving circuit in plan view) by etching or the like. Therefore, the conventional manufacturing process can be substantially followed as it is.

(Electronics)
Next, an embodiment of an electronic apparatus including the electro-optical device described in detail above will be described with reference to FIGS.

First, FIG. 4 shows a schematic configuration of an electronic apparatus having such an electro-optical device.
4, the electronic apparatus includes a display information output source 1000, a display information processing circuit 1002, a liquid crystal panel 10 as the above-described electro-optical device, a clock generation circuit 1008, and a power supply circuit 1010.

The display information output source 1000 includes a ROM (Read Only Memory), a RAM (Random Access Memory), a memory such as an optical disk device, a tuning circuit, and the like. Based on a clock signal from the clock generation circuit 1008, an image signal of a predetermined format, etc. Is output to the display information processing circuit 1002. The display information processing circuit 1002 includes various well-known processing circuits such as an amplification / polarity inversion circuit, a phase expansion circuit, a rotation circuit, a gamma correction circuit, and a clamp circuit. A digital signal is sequentially generated from the information and output to the driving circuit 1004 together with the clock signal CLK.

The driving circuit 1004 drives the liquid crystal panel 10 by the scanning line driving circuit 120 and the data line driving circuit 110 by the driving method described above. The power supply circuit 1010 supplies a predetermined power to each of the above-described circuits. Note that the drive circuit 1004 may be mounted on the TFT array substrate constituting the liquid crystal panel 10, and in addition, the display information processing circuit 1002 may be mounted.

Next, FIGS. 5 to 8 show specific examples of the electronic device configured as described above.
FIG. 5 is a sectional view showing an example of the liquid crystal projector. The liquid crystal projector 1100 is configured as a projection type projector including the above-described electro-optical device 10 as light valves 10R, 10G, and 10B for RGB. In the liquid crystal projector 1100, white light projected from a lamp unit 1102 of a white light source is guided to a plurality of mirrors 1106 inside a light guide 1104, and light components R corresponding to three primary colors of RGB are guided by two dichroic mirrors 1108. , G, and B. These light components R, G, and B are modulated by light valves 10R, 10G, and 10B corresponding to the respective colors, recombined by a dichroic prism 1112, and then projected on a screen or the like via a projection lens 1114. .

FIG. 6 is a front view showing an example of a laptop personal computer. The personal computer 1200 includes a main body 1204, a CPU, a memory, a modem, and a keyboard 1202, and further includes the above-described electro-optical device 10 as a display unit in a top cover case.

FIG. 7 is an exploded perspective view showing an example of a pager. The pager 1300 includes the above-described electro-optical device 10 as a display unit. The electro-optical device 10 includes a light guide 1306 including a backlight 1306a, a circuit board 1308, first and second shield plates 1310 and 1312, and two The elastic conductors 1314 and 1316 and the film carrier tape 1318 are housed in a metal frame 1302.

Note that the pager 1300 may have an external circuit section as shown in FIG. For example, in such a pager, a TCP (Tape Carrier Package) 1320 in which an IC 1324 including a display information processing circuit 1002 is mounted on a polyimide tape 1322 is physically attached to the active matrix substrate 1 via an anisotropic conductive film. And are electrically connected.

The electro-optical device according to the present embodiment includes, in addition to the electronic devices shown in FIGS. 5 to 8, a liquid crystal television, a viewfinder type or a monitor direct-view type video tape recorder, a car navigation device, an electronic notebook, a calculator, It can be used as a display portion of a word processor, a workstation, a mobile phone, a video phone, a POS terminal, a device including a touch panel, or the like.

Therefore, since the present electronic apparatus includes the electro-optical device according to the above-described embodiment as a display unit, it is possible to realize an electronic apparatus having a display unit capable of displaying high-quality images with less signal distortion.

The present invention is not limited to the above-described embodiment, and can be implemented with various modifications without departing from the spirit of the present invention.

For example, a precharge circuit may be formed on the active matrix substrate 100 in addition to the above-described scanning line driving circuit 120, data line driving circuit 110, and sample and hold circuit 130. This precharge circuit precharges the signal line 156 to a predetermined potential at a timing prior to the sampling of the image signal in order to reduce the load of writing the image signal to the signal line 156 of the data line driving circuit. It can be regarded as an auxiliary function of the data line driving circuit. Since the precharge circuit requires high-speed driving similarly to the sample and hold circuit 130, when the precharge circuit is formed on the active matrix substrate 100, the precharge circuit is provided in the common electrode 220 of the counter substrate 200. It is desirable to remove a portion overlapping in plan view with a precharge signal line for supplying a signal to the charge circuit or the precharge circuit by etching or the like.

In the present embodiment, only the portion of the common electrode 220 facing the peripheral driving circuit is removed, but the common electrode of a portion that does not contribute to display (that is, a region other than the display region 150) is removed. Can be completely removed. However, in this case, it is necessary to secure an electrode portion in order to establish conduction between the active matrix substrate 100 and the counter substrate 200 by the conduction member 106.

Further, in the present embodiment, the scanning line 155 is driven from both sides by the two scanning line driving circuits 120. However, if the delay of the scanning signal supplied to the scanning line 155 does not matter, one of The scanning line driving circuit 120 may be omitted, and the scanning line 155 may be driven by one scanning line driving circuit 120.

A color filter is provided on the counter substrate 200 according to the use of the electro-optical device, and a metal material such as Cr, Ni, Al, or C (carbon) or Ti (titanium) is provided between adjacent color filters. A light-shielding layer of resin black or the like in which the above is dispersed in a photoresist is provided. When the electro-optical device is used as a color light modulator such as a light valve of a projector, for example, a light-shielding film is formed on the counter substrate 200 without providing a color filter. Further, a front light or a backlight for irradiating the electro-optical device with light may be provided as necessary.

Further, in the liquid crystal layer 50 of the electro-optical device, in addition to the one in which the initial alignment state is defined by the alignment film, such as TN liquid crystal and STN liquid crystal, the liquid crystal molecules are arranged in a polymer so that the alignment state is random. Can be used. In the above description, the electro-optical device is described as a liquid crystal device. However, the present invention is not limited to this, and electroluminescence (EL), digital micromirror device (DMD), or plasma emission It is needless to say that the present invention can also be applied to an electro-optical device using various electro-optical elements using fluorescence or the like due to electron emission, and an electronic apparatus including the electro-optical device.

FIG. 1 is a plan view of an active matrix substrate of a liquid crystal device as an example of an electro-optical device according to an embodiment of the present invention, as viewed from a counter substrate side together with components formed thereon. FIG. 1 is a cross-sectional view of a liquid crystal device as an example of an electro-optical device according to an embodiment of the invention. FIG. 1 is a block diagram illustrating an electrical circuit configuration of a liquid crystal device as an example of an electro-optical device according to an embodiment of the invention. FIG. 2 is a block diagram illustrating a functional configuration of the electronic device of the present invention. FIG. 2 is a cross-sectional view illustrating a liquid crystal projector as an example of the electronic apparatus according to the invention. FIG. 21 is a front view illustrating a personal computer as another example of the electronic apparatus according to the invention. FIG. 14 is an exploded perspective view showing a pager as another example of the electronic apparatus of the invention. FIG. 11 is a perspective view illustrating a liquid crystal device using TCP as another example of the electronic apparatus according to the invention.

Explanation of reference numerals

50: liquid crystal layer, 100: active matrix substrate, 110: data line drive circuit, 111: sampling drive signal line (image signal selection line), 112: image signal line, 130 ...・ Sample hold circuit, 155 ・ ・ ・ Scan line, 156 ・ ・ ・ Signal line, 200 ・ ・ ・ Counter substrate, 220 ・ ・ ・ Common electrode

Claims (6)

A plurality of scanning lines, a plurality of signal lines provided so as to intersect the scanning lines, a plurality of pixel electrodes provided at intersections of the scanning lines and the signal lines, and a matrix of the pixels An active matrix substrate having a peripheral driving circuit to be driven on the same surface;
A common electrode is provided on one surface, and a counter substrate disposed to face the active matrix substrate so that the common electrode and the pixel electrode face each other;
A liquid crystal layer sandwiched between the active matrix substrate and the counter substrate,
An electro-optical device, wherein a portion of the common electrode that overlaps with the peripheral driving circuit or a wiring for supplying a signal to the peripheral driving circuit in a plan view is removed. 4. The electro-optical device according to claim 1, wherein the peripheral driving circuit includes a thin film transistor having a channel region made of single crystal silicon. 3. The electro-optical device according to claim 1, wherein at least one of the driving signals input to the peripheral driving circuit has a frequency of 10 MHz or more. The peripheral drive circuit includes one of a data line drive circuit and a sample hold circuit, and the wiring includes at least one of a clock signal line, an image signal selection line, and an image signal line. Item 5. The electro-optical device according to any one of Items 1 to 3. Forming a plurality of pixel electrodes and a peripheral drive circuit for driving the plurality of pixel electrodes in a matrix on one surface of an active matrix substrate;
A step of forming a common electrode over one surface of the counter substrate,
Removing the portion of the common electrode of the counter substrate that overlaps in plan view with the peripheral drive circuit or a wiring for supplying a signal to the peripheral drive circuit,
As the pixels and the common electrode face each other, the step of bonding the active matrix substrate and the counter substrate with a constant spacing by a sealant,
Forming a liquid crystal layer by injecting a liquid crystal into a space formed by the active matrix substrate, the counter substrate, and the sealant. An electronic apparatus comprising the electro-optical device according to claim 1.

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