JP3858572B2 - Electro-optic device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to the technical field of electro-optical devices such as liquid crystal devices, and in particular, according to image signals, clock signals, and the like by peripheral circuits such as data line driving circuits and sampling circuits provided in the peripheral region on the TFT array substrate. Belongs to the technical field of electro-optical devices of the type for driving data lines.
[0002]
[Background]
In the active matrix driving type electro-optical device by TFT driving, a large number of scanning electrodes and data lines arranged in the vertical and horizontal directions and a large number of pixel electrodes are provided on the TFT array substrate corresponding to respective intersections thereof. . In addition to these, peripheral circuits such as a data line driving circuit, a sampling circuit, and a scanning line driving circuit, and image signal lines and control signal lines connected to such peripheral circuits (for example, clock signal lines and waveform selection) In some cases, a signal line such as a signal line is provided in a peripheral region on the TFT array substrate.
[0003]
In this case, the data line driving circuit displays a control signal such as a reference clock (hereinafter referred to as an X-side reference clock) serving as a reference of the supply timing of the image signal and a waveform selection signal for preventing the so-called ghost. An image signal corresponding to the content of the power image, a positive or negative constant potential power source, and the like are supplied via an external input terminal and a wiring provided on the TFT array substrate, respectively. On the other hand, the scanning line driving circuit is provided with a reference clock (hereinafter referred to as a Y-side reference clock) serving as a reference for the scanning signal supply timing, a positive or negative constant potential power source, etc., which is also provided on the TFT array substrate. Supplied via input terminals and wiring. Then, for example, a scanning signal is supplied to the scanning line line-sequentially at a timing based on the Y-side reference clock by the scanning line driving circuit. In response to this, the data line driving circuit sequentially drives the sampling circuit that samples the input image signal at a timing based on the X-side reference clock, and the image signal is supplied from the sampling circuit to the data line. As a result, each TFT gate-connected to the scanning line is rendered conductive in response to the supply of the scanning signal, and an image signal is supplied to the pixel electrode via the data line and the TFT to display an image on each pixel. Done.
[0004]
In recent years, in particular, with the increase in the resolution of a display image, a serial image signal having a very high frequency has been input. For example, the dot frequency of the image signal is about 65 MHz in the XGA display mode used on a recent high-resolution personal computer screen, about 135 MHz in the SXGA display mode, and the dot frequency (about 30 MHz in the conventional VGA display mode). ) Much more. In order to cope with this, in particular, the frequency of the X-side reference clock supplied to the data line driving circuit becomes very high. Furthermore, in order to reduce the frequency of such a high image signal to a frequency that can be sampled by the sampling circuit, a high-frequency serial image signal is converted into a plurality of parallel images before being input to the electro-optical device. Processing for serial-parallel conversion of the signal is performed. For example, in the above-described VGA display mode, conversion into about 6 parallel image signals is performed, and in the XGA display mode and the SXGA display mode, for example, about 12 or 24, depending on the performance of the sampling circuit. Need to be converted into parallel image signals.
[0005]
[Problems to be solved by the invention]
However, under the recent demand for high-quality display images, the generation of high-frequency clock noise due to such a high reference clock frequency cannot be ignored. That is, for example, in the configuration in which the sampling circuit is driven by supplying the X-side reference clock having a relatively low frequency to the data line driving circuit, if the frequency of the clock signal is increased as it is, the image signal input to the sampling circuit High-frequency clock noise occurs in the image signal output from the sampling circuit and the image signal to be supplied to the data line. If the image signal changed in this way is received, the image displayed by each pixel electrode also changes. For example, when an intermediate level gradation display is performed in each pixel, even if a minute noise of about several mV to several tens of mV jumps into the image signal, it appears as a noise that can be visually recognized in the display image. . This is because the transmission of the liquid crystal with respect to the change in the liquid crystal driving voltage at the intermediate level is compared with the case where the white or black level display corresponding to the highest or lowest liquid crystal driving voltage (for example, a voltage between 0 to 5 V) is performed. This is because the rate change is steep. Thus, in order to realize high-precision multi-gradation display, the problem of high-frequency clock noise is serious.
[0006]
On the other hand, as described above, the frequency of the image signal supplied to the sampling circuit can be lowered by increasing the number of parallel image signals by serial-parallel conversion, but the image signal that must be provided on the substrate of the electro-optical device. The number of external input terminals for input and the number of image signal lines must be increased in response to the increase in the number of parallel image signals. Therefore, a large number of signal lines must be arranged in close proximity to a peripheral area on a limited substrate. As a result, one signal line (for example, a clock signal line) arranged in proximity is used as a noise source for other signal lines. There arises a problem that noise jumping into a signal on (for example, an image signal line) increases. In addition, as the number of parallel image signals by serial-parallel conversion is increased, block ghost generated due to insufficient writing ability to the pixel electrode (that is, corresponding to a plurality of data lines to which parallel image signals are supplied). The area occupied by the block-like ghost (generated as a group of pixel electrode groups) in the image display area increases. As a result, a serious problem that the block ghost becomes visually noticeable also occurs.
[0007]
The present invention has been made in view of the above-described problems, and provides an electro-optical device capable of displaying a high-quality image in which noise in a signal on a signal line provided in a peripheral region on a substrate is reduced. This is the issue.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the electro-optical device of the present invention has a plurality of pixel electrodes in the image display region on the substrate, and a capacitor line made of a first conductive film for adding a storage capacitor to the pixel electrodes, A data line made of a second conductive film laminated on the first conductive film via an interlayer dielectric film, and in the peripheral region located around the image display region on the substrate, the data line A peripheral circuit including a circuit related to driving; a signal line connected to the peripheral circuit and made of one of the first conductive film and the second conductive film; and the signal line electrically shielded from at least one direction. A shield made of the other of one conductive film and the second conductive film.
[0009]
According to the electro-optical device of the present invention, in the image display region, the second conductive film that forms the data line is laminated on the first conductive film that forms the capacitive line via the interlayer dielectric film. In the peripheral region, a signal line connected to the peripheral circuit is formed from one of the first conductive film and the second conductive film, and at least a signal line is connected from the other of the first conductive film and the second conductive film. A shield that electrically shields from one direction (for example, from above or below) is formed. Therefore, by forming the signal line in the peripheral region using the first conductive film forming the capacitor line and electrically shielding the signal line using the second conductive film forming the data line, the signal on the signal line is formed. It is possible to effectively reduce the jumping of electromagnetic noise into the antenna, or to effectively reduce the generation of electromagnetic noise from the signal line. Alternatively, a signal line on the signal line is formed by electrically shielding the signal line using the first conductive film forming the capacitor line while forming the signal line in the peripheral region using the second conductive film forming the signal line. It is possible to effectively reduce the jumping of electromagnetic noise into the antenna, or to effectively reduce the generation of electromagnetic noise from the signal line. Moreover, in any case, it is not necessary to separately form a dedicated film in order to form a signal line or a shield in the peripheral region, which is advantageous in simplifying the device configuration and the manufacturing process. In particular, when the pixel pitch is reduced and the drive frequency is increased in order to improve the image quality, the noise related to such signal lines generally increases relatively. Therefore, the configuration in which the signal lines such as the image signal lines and the control signal lines wired in the peripheral region as in the present invention are electrically shielded is very advantageous in reducing the pixel pitch or increasing the driving frequency.
[0010]
Of the peripheral circuits in the present invention, “a circuit related to driving a data line” refers to, for example, a data line driving circuit that drives a data line and a plurality of circuits that are controlled by a sampling circuit driving signal from the data line driving circuit. Including a sampling circuit for applying an image signal to a data line at a predetermined timing, a precharge circuit for supplying a precharge signal of a predetermined voltage level to a plurality of data lines in advance of the image signal, etc. This is a broad meaning including all circuits related to supply of image signals to the data lines. The “peripheral circuit” refers to, for example, a circuit related to driving of a scanning line, a quality related to the driving of a scanning line, a quality, a defect, etc. of the electro-optical device during manufacturing or at the time of shipment. An arbitrary circuit built in a peripheral region such as an inspection circuit.
[0011]
As a result, noise in the image signal and the like is reduced with a relatively simple device configuration, and an electro-optical device capable of displaying a high-quality image can be realized.
[0012]
In one aspect of the electro-optical device of the present invention, the shield is made of the second conductive film, and electrically shields the signal line made of the first conductive film from above.
[0013]
According to this aspect, a signal line such as an image signal line made of the first conductive film is electrically shielded from above by the shield made of the second conductive film. Accordingly, it is possible to effectively reduce electromagnetic noise jumping from other signal lines, wirings, circuits, and elements as noise sources located mainly above and to the sides of each signal line.
[0014]
In this aspect, the shield further includes a main line portion that electrically shields the signal line from above, and a side wall portion that extends from the main line portion and is buried in at least a groove dug in the interlayer insulating film, You may comprise so that the said signal line may be electrically shielded from three directions seeing on the cross section of the said signal line by the main line part and the said side wall part.
[0015]
If comprised in this way, signal lines, such as an image signal line which consists of a 1st electrically conductive film, are electrically shielded from the upper side and the three sides by the shield which consists of a 2nd electrically conductive film. Accordingly, it is possible to more effectively reduce electromagnetic noise jumping from other signal lines, wirings, circuits, or elements as noise sources located mainly above or to the sides of each signal line.
[0016]
In this case, the shield further includes a bottom wall portion made of another conductive film laminated via another interlayer disconnection film below the signal line, and the main line portion, the side wall portion, and the bottom You may comprise so that the said signal wire | line may be electrically shielded from four directions seeing on the cross section of the said signal wire | line by a wall part.
[0017]
If comprised in this way, signal lines, such as an image signal line which consists of a 1st electrically conductive film, are electrically shielded from upper, side, and lower four directions by the shield which consists of a 2nd electrically conductive film and another electrically conductive film. Therefore, the jumping of electromagnetic noise from other signal lines, wirings, circuits, and elements as noise sources located on the four sides of each signal line can be extremely effectively reduced.
[0018]
In another aspect of the electro-optical device of the present invention, the shield is made of the first conductive film, and electrically shields the signal line made of the second conductive film from below.
[0019]
According to this aspect, a signal line such as an image signal line made of the second conductive film is electrically shielded from below by the shield made of the first conductive film. Accordingly, it is possible to effectively reduce electromagnetic noise jumping from other signal lines, wirings, circuits, or elements as noise sources located mainly below or on the side of each signal line.
[0020]
In another aspect of the electro-optical device of the invention, the signal line includes an image signal line for supplying an image signal.
[0021]
According to this aspect, since the image signal line is electrically shielded in the peripheral area, electromagnetic noise jumps into the image signal on the image signal line from another signal line or wiring or circuit or element as a noise source. It can be effectively reduced. Therefore, it is possible to perform high-quality image display in the image display area based on an image signal having finally a high S / N.
[0022]
In another aspect of the electro-optical device according to the aspect of the invention, the peripheral circuit includes a sampling circuit that samples an image signal, and the signal line relays and connects the image signal line that supplies the image signal and the sampling circuit. Including relay wiring.
[0023]
According to this aspect, since the relay wiring is shielded in the peripheral region, it is effective to jump electromagnetic noise into the image signal on the relay wiring from other signal lines or wiring or circuits or elements as noise sources. Can be reduced. Therefore, it is possible to perform high-quality image display in the image display area based on an image signal having finally a high S / N. In particular, with respect to the relay wiring portion facing the counter electrode provided on the counter substrate, it is effective to electrically shield the relay wiring portion and the counter electrode with an upper shield disposed between them from the viewpoint of reducing the parasitic capacitance between the relay wiring portion and the counter electrode. is there.
[0024]
In another aspect of the electro-optical device of the invention, the peripheral circuit includes a sampling circuit that samples an image signal, and the signal line includes a gate signal line of the sampling circuit.
[0025]
According to this aspect, since the gate signal line of the sampling circuit is shielded in the peripheral region, the control signal (for example, the data line) on the gate signal line from another signal line or wiring or circuit or element as a noise source The jumping of electromagnetic noise into the sampling circuit drive signal output from the drive circuit can be effectively reduced. Therefore, finally, high-quality image display can be performed in the image display region by high-precision sampling operation in the sampling circuit. In particular, with respect to the gate signal line portion facing the counter electrode provided on the counter substrate, from the viewpoint of reducing the parasitic capacitance between the gate signal line portion and the counter electrode, it is effective to electrically shield by an upper shield disposed between the two. Is.
[0026]
In another aspect of the electro-optical device according to the aspect of the invention, the signal line includes a control signal line that supplies a control signal including at least one of a clock signal and a waveform selection signal.
[0027]
According to this aspect, since the control signal line is electrically shielded in the peripheral region, electromagnetic noise jumps into the control signal on the control signal line from another signal line or wiring or circuit or element as a noise source. It can be effectively reduced. Furthermore, generally, a control signal having a high frequency or a high potential tends to be a noise source for an image signal. Therefore, by electrically shielding the control signal line in this way, it is possible to effectively jump in electromagnetic noise from the control signal line as a noise source to an image signal or the like supplied to another image signal line or the like. Can be reduced. Therefore, it is possible to perform high-quality image display in the image display area based on a control signal, an image signal, or the like that finally has a high S / N.
[0028]
In the electro-optical device (including each embodiment) of the present invention described above, the shield is preferably fixed to the ground potential or other constant potential.
[0029]
In another aspect of the electro-optical device according to the aspect of the invention, the signal line includes an image signal line that supplies an image signal and a control signal line that supplies a control signal including at least one of a clock signal and a waveform selection signal. The shield includes a first portion that electrically shields the image signal line, and a second portion that electrically shields the control signal line, the first portion being fixed at a first constant potential, and the second portion being The second constant potential is different from the first constant potential.
[0030]
According to this aspect, since the image signal line is electrically shielded by the first portion of the shield and the control signal line is electrically shielded by the second portion of the shield in the peripheral region, the other signal as the noise source can be obtained. It is possible to effectively reduce electromagnetic noise jumping into the image signal on the image signal line and the control signal on the control signal line from the line, wiring, circuit or element. In particular, since the first part and the second part of the shield are fixed at different constant potentials, the potential fluctuations between the two signal lines affect each other via the same constant potential wiring. Can be prevented. Accordingly, it is possible to display a high-quality image in the image display area based on an image signal having a high S / N, a control signal, or the like.
[0031]
In another aspect of the electro-optical device of the present invention, the shield is divided for each signal line.
[0032]
According to this aspect, since each signal line is individually electrically shielded, each signal line can be electrically shielded from all other signal lines. That is, it is possible to reduce as much as possible the adverse effects caused by electromagnetic waves between a plurality of signal lines.
[0033]
In another aspect of the electro-optical device according to the aspect of the invention, the shield is divided for each of a plurality of signal lines.
[0034]
According to this aspect, since the signal lines are individually electrically shielded for each of the plurality of signal lines, the shield can be easily formed as compared with the case where the shield is provided for each signal line. At this time, for example, a plurality of signal lines such as a plurality of pixel signal lines that are basically affected by electromagnetic waves are collectively shielded by the same shield, and on the other hand, for example, an image signal line and a clock signal line, etc. If signal lines that are basically affected by electromagnetic waves are electrically shielded by separate shields, there is a disadvantage in collectively shielding a plurality of signal lines (ie, the same). (Jumping of noise between a plurality of signal lines electrically shielded by the shield) can be suppressed.
[0035]
In another aspect of the electro-optical device of the present invention, at least one of the first conductive film and the second conductive film is formed of a film containing a metal.
[0036]
According to this aspect, for example, the first conductive film and the second conductive film are formed from a film containing a metal such as an Al (aluminum) film or Cr (chromium), thereby reducing the resistance of these conductive films. It can be easily achieved.
[0037]
In another aspect of the electro-optical device according to the aspect of the invention, the image display region further includes a scanning line made of a third conductive film stacked on the substrate below the first conductive film, and the peripheral region has And further comprising another shield made of the third conductive film for electrically shielding the signal line from below.
[0038]
According to this aspect, in the image display region, the third conductive film that forms the scanning line is stacked below the first conductive film that forms the capacitance line. In the peripheral region, another shield that electrically shields the signal line from below is formed from the third conductive film. Accordingly, a signal line such as an image signal line formed of one of the first conductive film and the second conductive film is vertically moved by a shield formed of the other of the first conductive film and the second conductive film and a shield formed of the third conductive film. Or is shielded redundantly from below. Therefore, the jumping of electromagnetic noise from other signal lines, wirings, circuits, and elements as noise sources can be reduced more effectively. In the image display area, active matrix driving or passive matrix driving using scanning lines and data lines is possible.
[0039]
In another aspect of the electro-optical device according to the aspect of the invention, the image display region includes the thin film transistor connected between the data line and the pixel electrode, and the substrate that shields at least the channel region of the thin film transistor. 1 conductive film and a conductive light shielding film laminated below the thin film transistor, and further provided with another shield made of the light shielding film for electrically shielding the signal line from below in the peripheral region.
[0040]
According to this aspect, in the image display region, the light shielding film that shields at least the channel region of the thin film transistor is stacked below the first conductive film that forms the capacitive line. In the peripheral region, another shield that electrically shields the signal line from below is formed from this light shielding film. Therefore, a signal line such as an image signal line formed of one of the first conductive film and the second conductive film is formed from above or below by a shield formed of the other of the first conductive film and the second conductive film and a shield formed of the light shielding film. It is electrically shielded redundantly from below. Therefore, the jumping of electromagnetic noise from other signal lines, wirings, circuits, and elements as noise sources can be reduced more effectively. In the image display area, active matrix driving using data lines and thin film transistors is possible.
[0041]
In another aspect of the electro-optical device of the present invention, the electro-optical device further includes a counter electrode facing the plurality of pixel electrodes on a counter substrate facing the substrate via an electro-optical material, and the shield includes the signal A portion of the line that electrically shields a part of the signal line from above between the part facing the counter electrode and the counter electrode is included.
[0042]
According to this aspect, since the upper shield exists between the counter electrode provided on the counter substrate and a part of the signal line facing the counter electrode, the parasitic capacitance between the part of the signal line and the counter electrode is reduced. Can be reduced. That is, electromagnetic noise jumps into an image signal or the like on the signal line from the counter electrode as a noise source, or a constant potential signal on the counter electrode from the signal line as a noise source (for example, a constant potential signal that does not invert, a frame And electromagnetic noise jumping into a constant potential signal that is inverted for each field) can be effectively reduced.
[0043]
In another aspect of the electro-optical device according to the aspect of the invention, the shield includes a main line of a power supply line or a branch line.
[0044]
According to this aspect, since the shield is composed of the main line of the power supply wiring or the branch wiring, the shield can be fixed at a constant potential. In addition, since the region occupied by the shield in the peripheral region is assigned to the power supply wiring, the power supply wiring can be configured to be relatively wide and a stable constant potential can be supplied. Further, by sharing the shield and the power supply wiring, it is possible to simplify the device configuration and the manufacturing process. Furthermore, by fixing the shield to such a stable constant potential, the electric shielding performance is improved, which is further advantageous.
[0045]
In order to solve the above problems, another electro-optical device of the present invention is a capacitor line including a plurality of pixel electrodes and a first conductive film for adding a storage capacitor to the pixel electrodes in an image display region on the substrate. And a data line composed of a second conductive film laminated on the first conductive film via an interlayer dielectric film, and the data is provided in a peripheral region located around the image display region on the substrate. A peripheral circuit including a circuit for driving a line; an image signal line for supplying an image signal to the peripheral circuit and one of the first conductive film and the second conductive film; and a clock signal and a waveform for the peripheral circuit A control signal including at least one of the selection signals is supplied and a control signal line including the other of the first conductive film and the second conductive film is provided.
[0046]
According to another electro-optical device of the present invention, in the image display region, the second conductive film that forms the data line is stacked on the first conductive film that forms the capacitive line via the interlayer insulating film. In the peripheral region, an image signal line is formed from one of the first conductive film and the second conductive film, and a control signal line is formed from the other of the first conductive film and the second conductive film. Therefore, compared to the case where the image signal line and the control signal line are formed in the same plane by patterning the same conductive film in the peripheral region, the two conductive films forming the image signal line and the control signal line are different. The parasitic capacitance between the two is reduced by the distance away from the substrate in the direction perpendicular to the substrate. In other words, electromagnetic noise jumps into the image signal on the image signal line from the control signal line as the noise source that decreases as the distance between the two signal lines increases (or control from the image signal line as the noise source). Electromagnetic noise jumping into the control signal on the signal line can be reduced. The above-described various shields according to the present invention may be provided for the electro-optical device having such a configuration. With this configuration, the electromagnetic noise due to the separation of the image signal line and the control signal line in the direction perpendicular to the substrate and the electromagnetic noise due to the shield between the image signal and the control signal line are reduced. You can enjoy both of the effects.
[0047]
As a result, noise in the image signal and the like is reduced with a relatively simple device configuration, and an electro-optical device capable of displaying a high-quality image can be realized.
[0048]
Such an operation and other advantages of the present invention will become apparent from the embodiments described below.
[0049]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the electro-optical device of the invention is applied to a liquid crystal device.
[0050]
First, the configuration of the electro-optical device according to the embodiment of the invention will be described with reference to FIGS. 1 to 3. FIG. 1 is an equivalent circuit of various elements, wirings, and the like in a plurality of pixels formed in a matrix that forms an image display region of an electro-optical device. FIG. 2 is a plan view of a plurality of adjacent pixel groups on the TFT array substrate on which data lines, scanning lines, pixel electrodes and the like are formed. 3 is a cross-sectional view taken along line AA ′ of FIG. In FIG. 3, the scale of each layer and each member is different in order to make each layer and each member recognizable on the drawing.
[0051]
In FIG. 1, a pixel electrode 9a and a TFT 30 for controlling the switching of the pixel electrode 9a are formed on each of a plurality of pixels formed in a matrix that forms an image display area of the electro-optical device according to the present embodiment. The data line 6 a to which the image signal is supplied is electrically connected to the source of the TFT 30. The image signals S1, S2,..., Sn to be written to the data lines 6a may be supplied line-sequentially in this order, or may be supplied for each group to a plurality of adjacent data lines 6a. good. Further, the scanning line 3a is electrically connected to the gate of the TFT 30, and the scanning signals G1, G2,..., Gm are applied to the scanning line 3a in a pulse-sequential manner in this order at a predetermined timing. It is configured. The pixel electrode 9a is electrically connected to the drain of the TFT 30, and the image signal S1, S2,..., Sn supplied from the data line 6a is obtained by closing the switch of the TFT 30 serving as a switching element for a certain period. Write at a predetermined timing. Image signals S1, S2,..., Sn written in a liquid crystal as an example of an electro-optical material via the pixel electrode 9a are transmitted to a counter electrode (described later) formed on a counter substrate (described later). Held for a certain period of time. The liquid crystal modulates light and enables gradation display by changing the orientation and order of the molecular assembly depending on the applied potential level. In the normally white mode, the transmittance for incident light is reduced according to the voltage applied in units of each pixel, and in the normally black mode, the light is incident according to the voltage applied in units of each pixel. The light transmittance is increased, and light having a contrast corresponding to the image signal is emitted from the electro-optical device as a whole. Here, in order to prevent the held image signal from leaking, a storage capacitor 70 is added in parallel with the liquid crystal capacitor formed between the pixel electrode 9a and the counter electrode. A capacitor line 300 including a fixed potential side capacitor electrode of the storage capacitor 70 and fixed at a constant potential is provided alongside the scanning line 3a.
[0052]
In FIG. 2, a plurality of transparent pixel electrodes 9a (outlined by dotted line portions 9a ′) are provided in a matrix on the TFT array substrate of the electro-optical device. A data line 6a and a scanning line 3a are provided along each boundary.
[0053]
In addition, the scanning line 3a is disposed so as to face the channel region 1a ′ indicated by the hatched region rising to the right in the drawing in the semiconductor layer 1a, and the scanning line 3a functions as a gate electrode (particularly in the present embodiment). Then, the scanning line 3a is formed to be wide in the portion that becomes the gate electrode). As described above, the pixel switching TFT 30 in which the scanning line 3a is disposed as a gate electrode in the channel region 1a ′ is provided at each of the intersections of the scanning line 3a and the data line 6a.
[0054]
As shown in FIGS. 2 and 3, the storage capacitor 70 includes a relay layer 71 as a pixel potential side capacitor electrode connected to the high concentration drain region 1e (and the pixel electrode 9a) of the TFT 30, and a fixed potential side capacitor electrode. A part of the capacitor line 300 is formed so as to be opposed to each other through the dielectric film 75.
[0055]
The relay layer 71 functions as an intermediate conductive layer that relay-connects the pixel electrode 9a and the high-concentration drain region 1e of the TFT 30 via the contact holes 83 and 85 in addition to the function as the pixel potential side capacitor electrode of the storage capacitor 70. Has function.
[0056]
The capacitor line 300 extends in a stripe shape along the scanning line 3a as viewed in a plan view, and a portion overlapping the TFT 30 protrudes up and down in FIG. Such a capacitor line 300 preferably includes a first film made of a conductive polysilicon film having a thickness of about 50 nm and a second film made of a metal silicide film containing a refractory metal having a thickness of about 150 nm. It is configured to have a laminated multilayer structure. With this configuration, the second film functions not only as a fixed potential side capacitor electrode of the capacitor line 300 or the storage capacitor 70 but also as a light shielding layer that shields the TFT 30 from incident light above the TFT 30.
[0057]
On the other hand, below the TFT 30 on the TFT array substrate 10, a lower light-shielding film 11a is provided in a grid pattern. The lower light-shielding film 11a is made of, for example, at least one of refractory metals such as Ti (titanium), Cr (chromium), W (tungsten), Ta (tantalum), Mo (molybdenum), and Pb (lead). Including a single metal, an alloy, a metal silicide, a polysilicide, a laminate of these, and the like.
[0058]
A TFT array is formed by the data lines 6a extending in the vertical direction in FIG. 2 and the capacitor lines 300 extending in the horizontal direction in FIG. On the upper side and the lower side of the TFT 30 on the substrate 10, light shielding regions are configured in a lattice shape when seen in a plan view, and define an opening region of each pixel.
[0059]
In FIG. 3, a dielectric film 75 disposed between the relay layer 71 serving as a capacitor electrode and the capacitor line 300 is a silicon oxide film such as a relatively thin HTO film or LTO film having a film thickness of about 5 to 200 nm, for example. Or a silicon nitride film or the like. From the viewpoint of increasing the storage capacitor 70, the thinner the dielectric film 75 is better as long as the reliability of the film is sufficiently obtained.
[0060]
As shown in FIGS. 2 and 3, the data line 6a is electrically connected to the high-concentration source region 1d in the semiconductor layer 1a made of, for example, a polysilicon film through the contact hole 81. Note that a relay layer made of the same film as the relay layer 71 described above may be formed, and the data line 6a and the high-concentration source region 1d may be electrically connected through the relay layer and the two contact holes.
[0061]
Further, the capacitor line 300 extends from the image display region where the pixel electrode 9a is disposed to the periphery thereof, and is electrically connected to a constant potential source to be a fixed potential. As such a constant potential source, data for controlling a scanning line driving circuit (described later) for supplying a scanning signal for driving the TFT 30 to the scanning line 3a and a sampling circuit for supplying an image signal to the data line 6a. A constant potential source such as a positive power source or a negative power source supplied to a line driving circuit (described later) may be used, or a constant potential supplied to the counter electrode 21 of the counter substrate 20 may be used. Further, the lower light-shielding film 11 a provided on the lower side of the TFT 30 extends from the image display area to the periphery thereof in the same manner as the capacitor line 300 in order to avoid the potential fluctuation from adversely affecting the TFT 30. Then, it may be connected to a constant potential source.
[0062]
The pixel electrode 9a is electrically connected to the high-concentration drain region 1e in the semiconductor layer 1a through the contact holes 83 and 85 by relaying the relay layer 71. That is, in the present embodiment, the relay layer 71 fulfills the function of relaying the pixel electrode 9 a to the TFT 30 in addition to the function of the storage capacitor 70 as the pixel potential side capacitor electrode. As described above, the relay layer 71 is composed of two or more series contact holes having a relatively small diameter while avoiding the technical difficulty of connecting the two with a single contact hole even when the interlayer distance is as long as about 1000 nm. Both can be connected well, the pixel aperture ratio can be increased, and it is useful for preventing etching through when a contact hole is opened.
[0063]
2 and 3, the electro-optical device includes a TFT array substrate 10 and a transparent counter substrate 20 disposed to face the TFT array substrate 10. The TFT array substrate 10 is made of, for example, a quartz substrate, a glass substrate, or a silicon substrate, and the counter substrate 20 is made of, for example, a glass substrate or a quartz substrate.
[0064]
As shown in FIG. 3, the TFT array substrate 10 is provided with a pixel electrode 9a, and an alignment film 16 subjected to a predetermined alignment process such as a rubbing process is provided above the pixel electrode 9a. The pixel electrode 9a is made of a transparent conductive thin film such as an ITO (Indium Tin Oxide) film. The alignment film 16 is made of an organic thin film such as a polyimide thin film.
[0065]
On the other hand, a counter electrode 21 is provided over the entire surface of the counter substrate 20, and an alignment film 22 subjected to a predetermined alignment process such as a rubbing process is provided below the counter electrode 21. The counter electrode 21 is made of a transparent conductive thin film such as an ITO film. The alignment film 22 is made of an organic thin film such as a polyimide thin film.
[0066]
The counter substrate 20 may be provided with a lattice-shaped or striped light-shielding film. By adopting such a configuration, the incident light from the counter substrate 20 side is reduced to the channel region 1a ′ or the low level by the light shielding film on the counter substrate 20 together with the capacitor line 300 and the data line 6a constituting the light shield region as described above. Intrusion into the concentration source region 1b and the low concentration drain region 1c can be more reliably prevented. Further, such a light shielding film on the counter substrate 20 functions to prevent a temperature increase of the electro-optical device by forming at least a surface irradiated with incident light with a highly reflective film.
[0067]
Between the TFT array substrate 10 and the counter substrate 20, which are arranged in such a manner so that the pixel electrode 9 a and the counter electrode 21 face each other, an electro-optical material is placed in a space surrounded by a seal material described later. A liquid crystal layer 50 is formed by encapsulating liquid crystal as an example. The liquid crystal layer 50 takes a predetermined alignment state by the alignment films 16 and 22 in a state where no voltage is generated between the pixel electrode 9 a and the counter electrode 21. The liquid crystal layer 50 is made of, for example, a liquid crystal in which one kind or several kinds of nematic liquid crystals are mixed. The sealing material 52 is an adhesive made of, for example, a photocurable resin or a thermosetting resin for bonding the TFT array substrate 10 and the counter substrate 20 around them, and the distance between the two substrates is set to a predetermined value. Gap materials such as glass fiber or glass beads are mixed.
[0068]
Further, a base insulating film 12 is provided under the pixel switching TFT 30. The base insulating film 12 is formed on the entire surface of the TFT array substrate 10 in addition to the function of interlayer insulating the TFT 30 from the lower light-shielding film 11a, and thus remains rough after polishing the surface of the TFT array substrate 10 and after cleaning. It has a function of preventing changes in the characteristics of the pixel switching TFT 30 due to dirt or the like.
[0069]
In FIG. 3, a pixel switching TFT 30 has an LDD (Lightly Doped Drain) structure, and a scanning line 3a, a channel region 1a ′ of a semiconductor layer 1a in which a channel is formed by an electric field from the scanning line 3a, Insulating thin film 2 including a gate insulating film that insulates scanning line 3a from semiconductor layer 1a, low concentration source region 1b and low concentration drain region 1c of semiconductor layer 1a, high concentration source region 1d and high concentration drain region of semiconductor layer 1a 1e.
[0070]
On the scanning line 3a, a first interlayer insulating film 41 is formed in which a contact hole 81 leading to the high concentration source region 1d and a contact hole 83 leading to the high concentration drain region 1e are respectively opened.
[0071]
A relay layer 71 and a capacitor line 300 are formed on the first interlayer insulating film 41, and a contact hole 81 leading to the high-concentration source region 1d and a contact hole 85 leading to the relay layer 71 are opened on these, respectively. A holed second interlayer insulating film 42 is formed.
[0072]
In the present embodiment, the first interlayer insulating film 41 is baked at 1000 ° C. to activate ions implanted into the polysilicon film constituting the semiconductor layer 1a and the scanning line 3a. Also good. On the other hand, the stress generated in the vicinity of the interface of the capacitor line 300 may be reduced by not performing such firing on the second interlayer insulating film 42.
[0073]
A data line 6 a is formed on the second interlayer insulating film 42, and a flattened third interlayer insulating film 43 in which a contact hole 85 leading to the relay layer 71 is formed is formed thereon. . The pixel electrode 9a is provided on the upper surface of the third interlayer insulating film 43 thus configured.
[0074]
In the present embodiment, the surface of the third interlayer insulating film 43 is flattened by CMP (Chemical Mechanical Polishing) processing or the like, and liquid crystal caused by steps due to various wirings and elements existing therebelow. The alignment defect of the liquid crystal in the layer 50 is reduced.
[0075]
According to the present embodiment configured as described above, when incident light enters the channel region 1a ′ of the TFT 30 and the vicinity thereof from the counter substrate 20 side, the grid-like light shielding composed of the data line 6a and the capacitor line 300 is performed. Shading is performed with a layer. On the other hand, when returning light enters the channel region 1a ′ of the TFT 30 and its vicinity from the TFT array substrate 10 side, the light is blocked by the lower light-shielding film 11a (particularly, a plurality of projectors for a multi-plate color display or the like). When a single optical system is configured by combining the electro-optical devices with a prism or the like, the return light consisting of the projection light portion that penetrates the prism or the like from another electro-optical device is strong, so it is effective. is there.). As a result, the characteristics of the TFT 30 hardly change due to light leakage, and the electro-optical device can obtain very high light resistance. In addition, a large storage capacitor 70 can be constructed using the non-opening region of each pixel in which the data line 6a and the scanning line 3a are formed.
[0076]
Next, with reference to FIG. 4, the wiring and shield in the peripheral region in the present embodiment will be described. FIG. 4 is a schematic plan view showing the configuration of various wirings including a shield provided on the TFT array substrate and peripheral circuits in this embodiment.
[0077]
5 to 10 are cross-sectional views taken along the line BB ′ of FIG. 4 showing various specific examples of wiring such as a shield line, an image signal line, and a clock signal line.
[0078]
In FIG. 4, a data line driving circuit 101, a scanning line driving circuit 104, and a sampling circuit 301 are formed as an example of the peripheral circuit in the peripheral area located around the image display area on the TFT array substrate of the liquid crystal device. Yes.
[0079]
In the following description of FIG. 4, signal wirings 400 input via a plurality of external input terminals 102 provided along the lower side of the TFT array substrate 1 are denoted by the same alphabetic symbols as the signal names for ease of explanation. Are referred to by adding parentheses after the wiring 400 (for example, the signal wiring of the “clock signal CLX” is referred to as “wiring 400 (CLX)”).
The scanning line driving circuit 104 supplies a negative power supply VSSY and a positive power supply VDDY for the scanning line driving circuit 104 supplied from the external control circuit via the external input terminal 102, the wiring 400 (VSSY), and the wiring 400 (VDDY). The built-in shift register circuit is started by the input of the start signal SPY. Then, the reference clock signal CLY for the built-in shift register circuit of the scanning line driving circuit 104 and its inverted clock signal CLY ′ supplied through the external input terminal 102, the wiring 400 (CLY), and the wiring 400 (CLY ′). At a predetermined timing based on this, a scanning signal is applied to the scanning line 3a in a pulse-like manner in a line sequential manner.
[0080]
The data line driving circuit 101 receives a negative power supply VSSX and a positive power supply VDDX for the data line driving circuit 101 supplied from the external control circuit via the external input terminal 102, the signal wiring 400 (VSSX), and the wiring 400 (VDDX). As a power source, the built-in shift register circuit is started by input of a start signal SPX. Then, the reference clock signal CLX for the built-in shift register circuit of the data line driving circuit 101 and the inverted clock signal CLX ′ supplied through the external input terminal 102, the wiring 400 (CLX), and the wiring 400 (CLX ′). Based on the timing at which the scanning line driving circuit 104 applies the scanning signal, for example, 12 parallel signals supplied via the external input terminal 102 and the wiring 400 (VID1) to the wiring 400 (VID12) are serial-parallel. For each of the converted image signals VID1 to VID12, a sampling circuit drive signal Qm (m = 1, 2,...) Is supplied to the sampling circuit 301 via the sampling circuit drive signal line 306 for each data line 6a.
[0081]
The sampling circuit 301 includes a TFT 302 for each data line 6a. The wiring 400 (VID1) to the wiring 400 (VID12) are connected to the source electrode of the TFT 302 via the relay wiring 305, and the sampling circuit is driven. A signal line 306 is connected to the gate electrode of the TFT 302. When the image signals VID1 to VID12 are input, these image signals are sampled. When the sampling circuit driving signal Qm is input from the data line driving circuit 101 via the sampling circuit driving signal line 306, the image signals sampled for the image signals VID1 to VID12 are converted into 12 adjacent data lines. Sequentially applied to each group of 6a.
[0082]
As described above, the data line driving circuit 101 and the sampling circuit 301 are configured to supply the image signals VID1 to VID12 converted into 12 parallel signals to the data line 6a as the image signals S1, S2,. ing. In the present embodiment, the sampling circuit 301 connected to the 12 adjacent data lines 6a is simultaneously selected and sequentially transferred for each group of 12 data lines 6a. However, the data line 6a has been described. May be selected every 6 or every 24. Alternatively, two or more arbitrary numbers may be selected at the same time. At this time, it goes without saying that the external input terminals 102 and the image signal lines for image signals are required as many as the number of parallel image signals. Note that the number of parallel image signals and the number of sampling circuits 301 selected at the same time may be equal to each other, or the former may be configured to be greater than the latter.
[0083]
Further, as shown in FIG. 4, when the start signal SPX is input, the data line driving circuit 101 includes a shift register circuit 101a that starts sequential generation of transfer signals based on the reference clock signal CLX and its inverted clock signal CLK ′. The waveform control circuit 101b and the buffer circuit 101c are provided to the sampling circuit 301 through the sampling circuit drive signal line 306 after waveform shaping of the transfer signal from the shift register circuit 101a. The sampling circuit 301 has 12 TFTs 302 connected in parallel to each sampling circuit drive signal line 306 corresponding to the 12 image signals VID1 to VID12 that are serial-parallel converted. That is, the switches S1 to S12 configured by the TFT 302 are connected to the first sampling circuit drive signal line 306 from the left, and the switches S13 to S24 are connected to the second sampling circuit drive signal line 306 from the left. , Switches Sn-11 to Sn are connected to the rightmost sampling circuit drive signal line 306.
[0084]
Enable signals ENB1 and ENB2 as waveform selection signals which are one of the control signals are input to the waveform control circuit 101b. In this waveform control circuit 101b, the selection period of the sampling circuit 301 is set to (a sampling circuit driving signal that is in succession) by limiting the width of the pulses sequentially output from the shift register circuit 101a to the pulse widths of the enable signals ENB1 and ENB2. Control is performed so that periods in which Q1, Q2,... Are at a high level do not overlap each other. This prevents the occurrence of block ghost between the data lines 6a that receive image signals from the same wiring 400 (VID1) to wiring 400 (VID12). Therefore, the enable signals ENB1 and ENB2 are high-frequency control signals having a cycle shorter than the horizontal scanning period, like the clock signals CLX and CLX ′.
[0085]
In the present embodiment, vertical conduction terminals 106 for electrical conduction between the TFT array substrate 1 and the counter electrode 21 (see FIG. 3) on the counter substrate 20 side are provided at the four corners of the image display area. (However, two corners are shown in FIG. 4). The vertical conduction terminal 106 is supplied via the external input terminal 102 and the wiring 400 (LCCOM).
[0086]
Next, various specific examples of shields that can be employed in the electro-optical device according to the present embodiment are shown in FIGS. 5 to 10 are cross-sectional views showing structures of various specific examples of the shield in the BB 'cross section of FIG.
[0087]
5 to 10, in each of the specific examples, the wiring 400 (VID1) to the wiring 400 (VID12) which are image signal lines are the same conductive films (for example, conductive polylines) as the capacitor lines 300 in the image display region. These wirings 400 are at least electrically shielded by a shield made of the same film (for example, Al film) as the data lines 6a in the image display region. Has been.
[0088]
That is, in the specific example of FIG. 5, the wiring 400 made of the same conductive film as the capacitor line 300 is made of the same conductive film as the data line 6 a formed along the wiring 400 from above and covering the wiring 400. The upper shield 401a is electrically shielded. Particularly in this specific example, since the upper shield 401 a is divided for each wiring 400, each wiring 400 can be electrically shielded from all other wirings 400.
[0089]
In the specific example of FIG. 6, the wiring 400 made of the same conductive film as the capacitor line 300 has the same conductivity as the data line 6 a formed along the plurality of wirings 400 from above and covering the plurality of wirings 400 together. The upper shield 401b made of a film is electrically shielded. Particularly in this specific example, the upper shield 401b is divided for each of a plurality of signal lines. Therefore, the upper shield 401b can be formed relatively easily as compared with the specific example of FIG. 5 in which the upper shield 401a is provided for each signal line. At this time, a plurality of signal lines such as a plurality of pixel signal lines that are basically affected by electromagnetic waves are collectively shielded by one upper shield 401b, and on the other hand, for example, an image signal line and a clock signal Signal lines that are basically affected by electromagnetic waves such as lines may be electrically shielded by separate upper shields 401b. That is, this makes it possible to minimize the disadvantages of collectively shielding a plurality of signal lines.
[0090]
In the specific example of FIG. 7, in addition to the upper shield 401a shown in FIG. 5, the wiring 400 is electrically shielded from above and below from the lower shield 11b made of the same conductive film as the lower light shielding film 11a in the image display region. .
[0091]
In the specific example of FIG. 8, in addition to the upper shield 401a shown in FIG. 5, the wiring 400 is electrically shielded from the vertical direction by the lower shield 402 made of the same conductive film as the scanning line 3a in the image display region.
[0092]
In the specific example of FIG. 9, in addition to the upper shield 401c and the lower shield 11b similar to FIG. 7, the upper shield 401c is extended from the same conductive film, and the base insulating film 12, the first interlayer disconnection film 41, The wiring 400 is electrically shielded from the top, bottom, left, and right directions by a side shield 401 d embedded in a groove dug in the dielectric film 75 and the second interlayer insulating film 42 along the wiring 400. In particular, in this specific example, since the shield electrically shields the entire circumference of each wiring 400, adverse effects due to electromagnetic waves between the plurality of wirings 400 can be reduced as much as possible.
[0093]
In the specific example of FIG. 10, in addition to the upper shield 401c and the lower shield 402 similar to FIG. 8, the upper shield 401c is extended from the same conductive film, and the first interlayer dielectric film 41, the dielectric film 75, and The wiring 400 is electrically shielded from the top, bottom, left, and right directions by a side shield 401 e embedded in a groove dug in the second interlayer insulating film 42 along the wiring 400. In particular, in this specific example, since the shield electrically shields the entire circumference of each wiring 400, adverse effects due to electromagnetic waves between the plurality of wirings 400 can be reduced as much as possible.
As described above, according to the electro-optical device of this embodiment, in the image display region, the second conductive film forming the data line 6a is disposed on the first conductive film forming the capacitor line 300 via the interlayer insulating film. Are stacked. In the peripheral region, a wiring 400 connected to the peripheral circuit is formed from one of the first conductive film and the second conductive film, and at least the wiring 400 is connected from the other of the first conductive film and the second conductive film. A shield that electrically shields from one direction (for example, from above or below) is formed. Accordingly, it is possible to effectively reduce electromagnetic noise jumping into an image signal or the like on the wiring 400 such as an image signal line. Moreover, it is not necessary to separately form a dedicated film for forming the wiring 400 and the shield in the peripheral region, which is advantageous in simplifying the device configuration and the manufacturing process. In particular, when the pixel pitch is refined and the drive frequency is increased to improve the image quality, generally noise related to such signal lines (for example, image signals from control signal lines such as clock signal lines and waveform selection signal lines). Electromagnetic noise to the image signal on the line, electromagnetic noise to the image signal on the image signal line from the external device or other circuit, etc. from the control signal line such as clock signal line or waveform selection signal line to the external device or other circuit, etc. Electromagnetic noise, etc.) increases relatively (ie, S / N decreases). Therefore, the image signal line, the control signal line, and other wiring 400 wired in the peripheral area as in the present embodiment are shielded by the upper shield 401a, 401b or 401c, the lower shield 11b or 402, the side shield 401d or 401e, etc. Thus, the configuration of electrical shielding is very advantageous in reducing the pixel pitch or increasing the driving frequency.
[0094]
Further, in the present embodiment, the image signal line is electrically shielded particularly as the wiring 400. Therefore, the electromagnetic noise to the image signals S1, S2,... On the image signal line from other signal lines or wirings or circuits or elements as noise sources. Dive can be effectively reduced. Therefore, based on the image signals S1, S2,... Having a high S / N finally, it is possible to perform high-quality image display in the image display area.
[0095]
Further, in the embodiment described above, the relay wiring 305 and the sampling circuit drive signal line 306 for relay-connecting the image signal line and the sampling circuit 301 shown in FIG. 4 are arranged upward and downward as shown in FIGS. Alternatively, electrical shielding may be performed from the side. In this way, electromagnetic noise jumps into the image signals S1, S2,... On the relay wiring 305 and electromagnetic noise jumps into the sampling circuit drive signals Q1, Q2,. It can be effectively reduced. Since the relay wiring 305 and the sampling circuit drive signal line 306 include a portion facing the counter electrode 21 provided on the counter substrate 20, from the viewpoint of reducing the parasitic capacitance between the wiring and the counter electrode 21. It is particularly effective to be electrically shielded by the upper shield arranged at the top.
[0096]
Further, in the embodiment described above, the wiring 400 (CLX) and the wiring 400 (CLX ′) as clock signal lines, the wiring 400 (ENB1) and the wiring 400 (ENB2) as waveform selection signal lines are shown in FIGS. As shown in Fig. 5, the electric shielding may be performed from above, below or from the side. With this configuration, high-frequency and strong electromagnetic noise caused by a control signal having a high frequency and a high potential, which is likely to be a noise source for an image signal, on these control signal lines, is generated on the image signal lines and the like. It is possible to effectively prevent jumping into the image signal.
[0097]
In the electro-optical device (including each embodiment) of the present invention described above, the shield is preferably fixed to the ground potential or other constant potential. In particular, the image signal lines (wiring 400 (VID1), wiring 400 (VID2),...) And the control signal lines (wiring 400 (CLX), wiring 400 (CLX ′),...) Are electrically shielded separately. In addition, it is more preferable to fix them at different constant potentials. With this configuration, it is possible to prevent a situation in which the potential fluctuations between the two signal lines influence each other via the same constant potential wiring. For example, the image signal line is electrically shielded at a low potential by connecting it to the first constant potential line having a low potential (ground potential or about several volts), and the control signal line is set to a high potential (about several tens of volts). What is necessary is just to electrically shield with a high potential by connecting to the constant potential line of the 2nd constant potential.
[0098]
In addition, in the present embodiment, it is preferable to share the shield and the main line or branch wiring of the power supply wiring. With this configuration, the shield can be fixed at a constant potential while simplifying the device configuration and the manufacturing process. Moreover, since the area occupied by the shield in the peripheral area is allocated to the power supply wiring, the power supply wiring can be configured to be relatively wide. Furthermore, it is more advantageous to form the shield wider so that the performance of the shield is improved.
[0099]
5 to 10, the wiring 400 is formed from the same conductive film as the capacitor line 300 and the shield is formed from a conductive layer different from the capacitor line 300. However, the wiring 400 is the same as the data line 6a. The conductive film may be formed from a conductive layer different from the data line 6a, or the wiring 400 may be formed from the same conductive film as the scanning line 3a and the shield may be formed from a conductive layer different from the scanning line 3a. Alternatively, the wiring 400 may be formed from the same conductive film as the lower light-shielding film 11a, and the shield may be formed from a conductive layer different from the lower light-shielding film 11a.
[0100]
Furthermore, a part of the shield can be formed from the same film as the wiring, and in this case, it is possible to electrically shield mainly from the side. In the present embodiment, as shown in FIG. 4, the wiring 400 (VSSY) for supplying the negative power supply VSSY and the wiring 400 (VSSX) for supplying the negative power supply VSSX in the same plane are the wiring 400 ( VID2), wiring 400 (VID4), wiring 400 (VID6),... Are functioning as image signal shield lines. Similarly, the wiring 400 (VDDY) for supplying the positive power supply VDDY and the wiring 400 (VSSX) for supplying the negative power supply VSSX are the image signal lines 400 (VID1), 400 (VID3), and 400 in the same plane. (VID5),... And functions as an image signal shield line. Further, the wiring 400 (VDDX) for supplying the positive power supply VDDX also surrounds control signal lines such as the wiring 400 (CLX) and the wiring 400 (CLX ′) as clock signal lines in the same plane, and the control signal shield. It functions as a line. Similarly, the wiring 400 (VDDY) that supplies the positive power supply VDDY surrounds control signals such as the wiring 400 (CLY) and the wiring 400 (CLY ′) as clock signal lines in the same plane, and the control signal shield line. Is functioning as In particular, as shown by a broken line in FIG. 4, two ends of the wiring 400 (VDDX) as the control signal shield line may be connected to each other by the connecting portion 93, and similarly as the image signal shield line. Two ends of the wiring 400 (VSSX) may be connected to each other by the connecting portion 91.
[0101]
Furthermore, it is possible to construct both laminated conductive films from a low-resistance Al film, which makes it possible to electrically shield low-resistance wiring with a low-resistance conductive film. A configuration in which electromagnetic noise hardly enters can be obtained.
[0102]
In the embodiment described above, a large number of conductive layers are stacked as shown in FIG. 3, so that the data line 6a and the scanning line 3a on the lower ground of the pixel electrode 9a (that is, the surface of the third interlayer insulating film 43). The level difference in the region along the line is alleviated by flattening the surface of the third interlayer insulating film 43, but instead of or in addition to this, the TFT array substrate 10, the base insulating film 12, the first A planarization process may be performed by digging a groove in the first interlayer insulating film 41, the second interlayer insulating film 42, or the third interlayer insulating film 43 and embedding the wiring such as the data line 6a, the TFT 30, or the like. The planarization process may be performed by polishing a step on the upper surface of the interlayer insulating film 42 by a CMP (Chemical Mechanical Polishing) process or the like, or by forming it flat using an organic SOG.
[0103]
In the embodiment described above, the pixel switching TFT 30 preferably has an LDD structure as shown in FIG. 3, but does not implant impurities into the low concentration source region 1b and the low concentration drain region 1c. Alternatively, the TFT may be a self-aligned TFT in which a high concentration source and drain regions are formed in a self-aligned manner by implanting impurities at a high concentration using a gate electrode formed of a part of the scanning line 3a as a mask. In this embodiment, only one gate electrode of the pixel switching TFT 30 is arranged between the high concentration source region 1d and the high concentration drain region 1e. However, two or more gate electrodes are provided between these gate electrodes. You may arrange. If the TFT is configured with dual gates or triple gates or more in this way, leakage current at the junction between the channel and the source and drain regions can be prevented, and the off-time current can be reduced.
[0104]
In addition, as a modification of the embodiment of the present invention described above, instead of or in addition to providing various shields as shown in FIG. 5 to FIG. A wiring 400 (CLX), a wiring 400 (CLY),... Serving as control signal lines are formed from one of the four conductive films of the line 6a, the scanning line 3a, and the lower light-shielding film 11a. The wiring 400 (VID1), the wiring 400 (VID2),... Which are image signal lines may be formed from the other film. With this configuration, both signal lines are separated in the direction perpendicular to the substrate and between the two signal lines, compared to the case where these two types of wirings are formed in the same plane by patterning the same conductive film. This is advantageous because noise jumps between both signal lines can be reduced by the amount of the interlayer insulating film. That is, even if there is no shield, it is possible to reduce noise by forming these two types of signal lines so as to be separated in a direction perpendicular to the substrate. Furthermore, the effect of reducing electromagnetic noise can be further enhanced by combining such a configuration with the above-described various shields.
[0105]
(Overall configuration of electro-optical device)
The overall configuration of the electro-optical device according to each embodiment configured as described above will be described with reference to FIGS. 11 and 12. 11 is a plan view of the TFT array substrate 10 as viewed from the counter substrate 20 side together with the components formed thereon, and FIG. 12 is a cross-sectional view taken along the line HH ′ of FIG.
[0106]
In FIG. 12, a sealing material 52 is provided on the TFT array substrate 10 along the edge thereof, and a light shielding film 53 as a frame defining the periphery of the image display region 10a is provided in parallel to the inside thereof. Is provided. A data line driving circuit 101 and an external circuit connection terminal 102 are provided along one side of the TFT array substrate 10 in a region outside the sealing material 52, and the scanning line driving circuit 104 has two sides adjacent to the one side. It is provided along. Needless to say, if the delay of the scanning signal supplied to the scanning line 3a is not a problem, the scanning line driving circuit 104 may be provided on only one side. The data line driving circuit 101 may be arranged on both sides along the side of the image display area 10a. Further, on the remaining side of the TFT array substrate 10, a plurality of wirings 105 are provided for connecting between the scanning line driving circuits 104 provided on both sides of the image display region 10a. Further, at least one corner portion of the counter substrate 20 is provided with a vertical conductive material 106 for electrical connection between the TFT array substrate 10 and the counter substrate 20. Further, the sampling circuit 301 shown in FIG. 4 is provided in the frame area. As shown in FIG. 12, the counter substrate 20 having substantially the same contour as the sealing material 52 shown in FIG. 11 is fixed to the TFT array substrate 10 by the sealing material 52.
[0107]
On the TFT array substrate 10, in addition to the data line driving circuit 101, the scanning line driving circuit 104, the sampling circuit 301 and the like, a precharge signal having a predetermined voltage level is applied to the plurality of data lines 6a before the image signal. In addition, a precharge circuit to be supplied, an inspection circuit for inspecting quality, defects, and the like of the electro-optical device during manufacture or shipment may be formed.
[0108]
In the embodiment described above with reference to FIGS. 1 to 12, instead of providing the data line driving circuit 101 and the scanning line driving circuit 104 on the TFT array substrate 10, for example, they are mounted on a TAB (Tape Automated Bonding) substrate. The drive LSI may be electrically and mechanically connected via an anisotropic conductive film provided on the periphery of the TFT array substrate 10. Further, for example, a TN mode, a VA (Vertically Aligned) mode, a PDLC (Polymer Dispersed Liquid Crystal) mode, and the like are respectively provided on the side on which the projection light of the counter substrate 20 enters and the side on which the emission light of the TFT array substrate 10 exits. A polarizing film, a retardation film, a polarizing plate, and the like are arranged in a predetermined direction according to the operation mode and the normally white mode / normally black mode.
[0109]
Since the electro-optical device in the embodiment described above is applied to a projector, three electro-optical devices are respectively used as RGB light valves, and each light valve is connected to a dichroic mirror for RGB color separation. The light of each color that has been decomposed is incident as projection light. Therefore, in each embodiment, the counter substrate 20 is not provided with a color filter. However, an RGB color filter may be formed on the counter substrate 20 together with its protective film in a predetermined region facing the pixel electrode 9a. In this way, the electro-optical device in each embodiment can be applied to a direct-view type or reflective type color electro-optical device other than the projector. Further, micro lenses may be formed on the counter substrate 20 so as to correspond to one pixel. Alternatively, it is also possible to form a color filter layer with a color resist or the like under the pixel electrodes 9 a facing RGB on the TFT array substrate 10. In this way, a bright electro-optical device can be realized by improving the collection efficiency of incident light. Furthermore, a dichroic filter that produces RGB colors by using interference of light may be formed by depositing several layers of interference layers having different refractive indexes on the counter substrate 20. According to this counter substrate with a dichroic filter, a brighter color electro-optical device can be realized.
[0110]
The present invention is not limited to the above-described embodiments, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification. The apparatus and the manufacturing method thereof are also included in the technical scope of the present invention.
[Brief description of the drawings]
FIG. 1 is an equivalent circuit of various elements, wirings, and the like provided in a plurality of matrix-like pixels constituting an image display area in an electro-optical device according to an embodiment of the invention.
FIG. 2 is a plan view of a plurality of pixel groups adjacent to each other on a TFT array substrate on which data lines, scanning lines, pixel electrodes and the like are formed in the electro-optical device according to the embodiment.
FIG. 3 is a cross-sectional view taken along the line AA ′ in FIG.
FIG. 4 is a schematic plan view showing configurations of various wirings including a shield provided on the TFT array substrate, peripheral circuits, and the like in the present embodiment.
5 is a cross-sectional view taken along the line BB ′ of FIG. 4 according to a specific example of a shield that can be employed in the present embodiment.
6 is a cross-sectional view taken along the line BB ′ of FIG. 4 according to another specific example of a shield that can be employed in the present embodiment.
7 is a cross-sectional view taken along the line BB ′ of FIG. 4 according to another specific example of a shield that can be employed in the present embodiment.
8 is a cross-sectional view taken along the line BB ′ of FIG. 4 according to another specific example of a shield that can be employed in the present embodiment.
9 is a cross-sectional view taken along the line BB ′ of FIG. 4 according to another specific example of a shield that can be employed in the present embodiment.
10 is a cross-sectional view taken along the line BB ′ of FIG. 4 according to another specific example of a shield that can be employed in the present embodiment.
FIG. 11 is a plan view of the TFT array substrate in the electro-optical device according to the embodiment viewed from the side of the counter substrate together with each component formed thereon.
12 is a cross-sectional view taken along the line HH ′ of FIG.
[Explanation of symbols]
1a ... Semiconductor layer
1a '... channel region
1b ... low concentration source region
1c: low concentration drain region
1d ... High concentration source region
1e ... High concentration drain region
2… Insulating thin film
3a ... scan line
6a ... Data line
9a: Pixel electrode
10 ... TFT array substrate
11a: Lower light shielding film
12 ... Underlying insulating film
16 ... Alignment film
20 ... Counter substrate
21 ... Counter electrode
22 ... Alignment film
30 ... TFT
50 ... Liquid crystal layer
70 ... Storage capacity
71 ... Relay layer
75 ... Dielectric film
81, 83, 85 ... contact holes
101: Data line driving circuit
101a: Shift register circuit
101b ... Waveform control circuit
101c... Buffer circuit
104: Scanning line driving circuit
300 ... capacity line
301: Sampling circuit
302 ... TFT of sampling circuit
305 ... Relay wiring
306 ... Sampling circuit drive signal line
400 ... wiring
401a, 401b, 401c ... Upper shield
401d, 401e ... side shield
402 ... lower shield

Claims (14)

A plurality of pixel electrodes, a capacitor line made of a first conductive film for adding a storage capacitor to the pixel electrode, and an interlayer insulation film are stacked on the first conductive film in an image display region on the substrate. A data line made of the second conductive film formed,
A peripheral circuit including a circuit related to driving of the data line in a peripheral region located around the image display region on the substrate; a signal line connected to the peripheral circuit and made of the first conductive film; An electro-optical device comprising a shield made of the second conductive film and electrically shielding the signal line from above.   The shield further includes a main line portion that electrically shields the signal line from above, and a side wall portion that extends from the main line portion and is buried in at least a groove dug in the interlayer insulating film. 2. The electro-optical device according to claim 1, wherein the signal line is electrically shielded from three sides when viewed on a cross section of the signal line by a side wall portion.   The shield further includes a bottom wall portion made of another conductive film laminated via another interlayer disconnection film below the signal line, and the main line portion, the side wall portion, and the bottom wall portion make the The electro-optical device according to claim 2, wherein the signal line is electrically shielded from four directions when viewed on a cross section of the signal line.   The electro-optical device according to claim 1, wherein the signal line includes an image signal line that supplies an image signal. The peripheral circuit includes a sampling circuit that samples an image signal;
5. The electro-optical device according to claim 1, wherein the signal line includes a relay wiring that relay-connects the image signal line for supplying the image signal and the sampling circuit. 6. The peripheral circuit includes a sampling circuit that samples an image signal;
6. The electro-optical device according to claim 1, wherein the signal line includes a gate signal line of the sampling circuit.   The electro-optical device according to claim 1, wherein the signal line includes a control signal line that supplies a control signal including at least one of a clock signal and a waveform selection signal. The signal line includes an image signal line for supplying an image signal and a control signal line for supplying a control signal including at least one of a clock signal and a waveform selection signal,
The shield includes a first portion that electrically shields the image signal line, and a second portion that electrically shields the control signal line,
The first part is fixed at a first constant potential, and the second part is fixed at a second constant potential different from the first constant potential. The electro-optical device described.   The electro-optical device according to claim 1, wherein the shield is divided for each signal line.   The electro-optical device according to claim 1, wherein the shield is divided for each of a plurality of signal lines.   The electro-optical device according to claim 1, wherein at least one of the first conductive film and the second conductive film is formed of a film containing a metal. The image display area further includes a scanning line made of a third conductive film stacked below the first conductive film on the substrate,
The electro-optical device according to claim 1, further comprising another shield made of the third conductive film that electrically shields the signal line from below in the peripheral region. A thin film transistor connected between the data line and the pixel electrode, and a layer below the first conductive film and the thin film transistor on the substrate that shields at least a channel region of the thin film transistor in the image display region. A conductive light shielding film,
13. The electro-optical device according to claim 1, further comprising another shield made of the light-shielding film that electrically shields the signal line from below in the peripheral region.   The electro-optical device according to claim 1, wherein the shield includes a main line or a branch line of power supply wiring.

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