JP2006267545A - Electrooptical apparatus and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a matrix structure capable of effectively protecting the components of the matrix structure from electrostatic destruction, and electronic equipment. <P>SOLUTION: This electrooptical apparatus comprises: a structure wherein a plurality of gate lines 4a, 4b and 4c arranged in an X axis direction and a plurality of data lines 3a, 3b and 3c arranged in a Y axis direction cross in a grid shape; a TFT 2 arranged at the crossing part; a liquid crystal pixel 1 driven by signals flowing through the TFT 2; a common electrode line 5 turned to a reference potential; and a capacitor C arranged in at least one of a part between the gate lines 4a, 4b and 4c and the common electrode line 5 and a part between the data lines 3a, 3b and 3c and the common electrode line 5. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electro-optical device and an electronic apparatus.

  TFT liquid crystal display devices that control the display of each pixel area of a liquid crystal display device using thin film transistors (TFTs) are applied to flat-screen TVs, personal computer monitors, PDAs (Personal Digital Assistants), mobile phones, etc. The market is expanding rapidly. By the way, in a TFT liquid crystal display device, there may be a display defect such as a dot defect in which only a black spot or a white spot is displayed at a specific part on the display screen, or display unevenness. Such a display defect is mainly caused by a TFT that drives and controls each pixel being destroyed by static electricity or the like. This electrostatic breakdown is mechanical or electrical under a predetermined environment such as temperature and humidity at the time of mounting, assembly or shipment, storage, and use of the product after shipment in the TFT liquid crystal display device manufacturing process. Caused by contact.

As an electrostatic protection circuit of a conventional liquid crystal display device, a protective diode made of a TFT is arranged between a scanning line (gate line) or signal line (data line) and a common electrode line (line serving as a reference potential). There is what I did. This is because when an excessive voltage due to static electricity is applied to the scanning line or signal line of the liquid crystal display device, the protective TFT that forms the protective diode is turned on by the excessive voltage, and the static electricity flows through the common electrode line. Thus, the pixel driving TFT is to be protected (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 10-10493

  However, the conventional electrostatic protection circuit described in Patent Document 1 may not sufficiently protect the pixel driving TFT and the like. That is, there is a case that the current due to the static electricity destroys the gate insulating film of the pixel driving TFT or the like faster than the protective TFT is turned on by static electricity. The distance between the source and drain of the TFT is generally 3 to 4 μm, which is longer than the thickness of the gate insulating film. Accordingly, before the excessive voltage applied to the scanning line or the like is reduced to an allowable voltage due to static electricity flowing between the source and drain of the protective TFT, the gate insulating film of the pixel driving and protective TFT is caused by the excessive voltage. Static electricity will flow through and the insulating film will be destroyed.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an electro-optical device and an electronic apparatus that can effectively protect components of the electro-optical device from electrostatic breakdown.
Another object of the present invention is to provide an electro-optical device and an electronic apparatus that can effectively protect components such as switching elements in the electro-optical device from electrostatic breakdown by a simple electrostatic protection circuit.
It is another object of the present invention to provide an electro-optical device and an electronic apparatus that can effectively protect components of the electro-optical device from electrostatic breakdown while suppressing an increase in manufacturing cost.

In order to achieve the above object, an electro-optical device of the present invention includes a structure in which a plurality of gate lines arranged in the X-axis direction and a plurality of data lines arranged in the Y-axis direction intersect each other, A switching element disposed at an intersection, a pixel electrode disposed corresponding to the switching element, a common electrode line set to a reference potential, a space between the gate line and the common electrode line, and the data line And a common electrode line, and at least one of the capacitors.
According to the present invention, components of the electro-optical device can be effectively protected from electrostatic breakdown. For example, there may be a case where static electricity is applied to a portion of a single data line in the electro-optical device and an excessive voltage is applied to the portion. At this time, the electrostatic charge flows into a capacitor disposed between the data line and the common electrode line, and charges and discharges the capacitor. As a result, an excessive voltage (for example, 1000 volts) due to static electricity is rapidly lowered to an allowable voltage (for example, 100 volts) or less by the capacitor. Therefore, the electro-optical device of the present invention can reduce an excessive voltage due to static electricity to an allowable voltage or less of the switching element or the like before the switching element or the like is destroyed, and effectively protects the components from the electrostatic breakdown. be able to.

In the electro-optical device according to the aspect of the invention, it is preferable that the capacitor protects components of the electro-optical device from electrostatic breakdown.
According to the present invention, since the capacitor can exhibit only the electrostatic protection function, the components of the electro-optical device can be electrostatically discharged without damaging the original function (display function, etc.) of the electro-optical device. It can be effectively protected from destruction.

In the electro-optical device according to the aspect of the invention, the capacitor may have a capacitance between the control end and the input end of the switching element as a first capacitance, and a capacitance between the control end and the output end of the switching element as a second capacitance. In this case, it is preferable that the capacity is 10 times or more of the first capacity or the second capacity.
According to the present invention, the switching element, which is a component of the electro-optical device, can be effectively protected from electrostatic breakdown. For example, there may be a case where static electricity is applied to a portion of a single data line in the electro-optical device and an excessive voltage is applied to the portion. At this time, the overvoltage is V (volts), the electrostatic charge Q (coulomb), and the first capacitance or the second capacitance of the switching element in the vicinity of the portion where the static electricity is applied is the capacitance C (farad). These relationships are expressed by the following mathematical formula (1).
V = Q / C (1)
Then, when there is no capacitor, an excessive voltage (for example, 1000 volts) is applied to the switching element as it is. On the other hand, when there is the capacitor, the capacitance C is added by the capacitance of the capacitor in the equation. And when the capacity | capacitance of a capacitor | condenser is 10 times the 1st capacity | capacitance or a 2nd capacity | capacitance, it becomes following Numerical formula (2).
V = Q / 11C (2)
Therefore, according to the present invention, the excessive voltage of static electricity (for example, 1000 volts) can be reduced to 1/10 or less (100 volts or less).

In the electro-optical device according to the aspect of the invention, it is preferable that the capacitor has a capacitance that does not change the content of a signal applied to the gate line or the data line to which one end of the capacitor is connected.
In the electro-optical device according to the aspect of the invention, the capacitance of the capacitor connected to one of the gate lines or the data lines includes a plurality of the switching elements connected to the one gate line or the data lines. It is preferably 50% or less of the total of the first capacity or the second capacity.
According to the present invention, for example, when 200 switching elements are connected to one gate line, the gate line has a capacitance of 200C obtained by multiplying the capacitance C of one switching element by 200. It will be. Then, if the capacitance of the capacitor is 50% or less of 200C, when one capacitor is connected to one gate line, the gate line has a capacitance of {200C + 200C × 0.5} = 300C or less. Become. Therefore, since the increase in the capacitance of the entire gate line due to the connection of the capacitor to the gate line is 50% or less, it is avoided that the capacitor affects the original scanning signal applied to the gate line. can do. On the other hand, since the capacitance of the capacitor is nearly 100 times the capacitance of one switching element to be destroyed by static electricity, an excessive voltage due to static electricity can be reduced to nearly 1/100. Here, the charge amount of static electricity is generally smaller than the charge amount sent from the signal source of the original signal applied to the gate line or the data line. Therefore, the capacitor can sufficiently reduce the excessive voltage due to static electricity without affecting the original signal.

The electro-optical device according to the aspect of the invention may be configured such that the capacitance of the capacitor connected to one gate line or data line is a plurality of the switching elements connected to the one gate line or data line. It is preferable to be within the range of 5 to 30 percent (especially 10 percent is preferable) of the total of the first capacity or the second capacity.
According to the present invention, since the capacity of the capacitor is 5 to 30% with respect to the capacity of one gate line or the entire data line, the capacitor affects the original signal waveform of the gate line or the data line. It can be avoided. Further, assuming that 200 switching elements are connected to one gate line or data line, the capacitance of the capacitor is 10 to 60 times that of one switching element. The overvoltage can be reduced to 1/10 to 1/60.

In the electro-optical device according to the aspect of the invention, it is preferable that the capacitor is disposed in the vicinity of the outer periphery of the electro-optical device.
According to the present invention, a plurality of capacitors for electrostatic protection can be arranged without affecting the arrangement of original components such as gate lines, data lines, common electrode lines, and switching elements in the electro-optical device. . Therefore, according to the present invention, electrostatic breakdown can be effectively prevented while maintaining a high-density arrangement of the components of the electro-optical device.

The electro-optical device of the present invention is a component of a liquid crystal display device, the driving element is a pixel having a liquid crystal sandwiched between the pixel electrode and a counter electrode, and the switching element is a thin film transistor. Preferably, the gate of the thin film transistor is connected to the gate line, and the thin film transistor supplies a signal from the data line to the pixel electrode based on a signal supplied to the gate line.
According to the present invention, it is possible to effectively avoid electrostatic breakdown of a thin film transistor or the like of a liquid crystal display device. Therefore, according to the present invention, a liquid crystal display device highly resistant to static electricity can be provided at low cost.

In the electro-optical device according to the aspect of the invention, it is preferable that the capacitor is disposed so as to overlap a peripheral parting disposed in the periphery of the display area of the liquid crystal display device.
According to the present invention, it is possible to increase resistance to static electricity while arranging TFTs, pixel electrodes, and the like in a display area of a liquid crystal display device at high density. Accordingly, an image can be displayed with high quality, and a liquid crystal display device with high resistance to static electricity, high reliability, and long life can be provided at low cost.

In the electro-optical device according to the aspect of the invention, it is preferable that the capacitor is formed in the thin film transistor forming step.
According to the present invention, it is possible to form a protective capacitor in the TFT formation process at the time of manufacturing the electro-optical device. Therefore, the present invention can provide an electro-optical device that is resistant to static electricity while suppressing an increase in manufacturing cost.

In the electro-optical device according to the aspect of the invention, the capacitor includes a pair of opposing first and second electrodes, and an insulating film sandwiched between the first electrode and the second electrode. The first electrode of the capacitor is made of the same constituent material as the gate electrode of the thin film transistor, the insulating film of the capacitor is made of the same constituent material as the gate insulating film of the thin film transistor, and the second electrode of the capacitor is made of the thin film transistor It is preferable that it consists of the same constituent material as a source electrode or a drain electrode.
According to the present invention, when the electro-optical device is manufactured, the first electrode of the capacitor can be formed when forming the gate electrode of the TFT, and the insulating film of the capacitor can be formed when forming the insulating film of the TFT. The second electrode of the capacitor can be formed when forming the source or drain electrode. In other words, the capacitor first electrode can be formed in the same layer as the TFT gate electrode formation layer, the capacitor insulation film can be formed in the same layer as the TFT insulation film formation layer, the TFT source electrode or The second electrode of the capacitor can be formed of the same layer as the drain electrode formation layer. Therefore, the present invention can provide an electro-optical device that is resistant to static electricity and inexpensive.

In the electro-optical device according to the aspect of the invention, the capacitor includes a pair of opposing first and second electrodes, and an insulating film sandwiched between the first electrode and the second electrode. The first electrode of the capacitor has the same thickness as the gate electrode of the thin film transistor, the insulating film of the capacitor has the same thickness as the gate insulating film of the thin film transistor, and the second electrode of the capacitor has the same thickness as the gate electrode of the thin film transistor. The film thickness is preferably the same as that of the source or drain electrode.
According to the present invention, when forming a capacitor for electrostatic protection, steps such as adjusting the thicknesses of the first electrode, the second electrode, and the insulating film by an etching process or the like can be eliminated. Therefore, the present invention can provide an electro-optical device that is more inexpensive and resistant to static electricity.

In the electro-optical device according to the aspect of the invention, it is preferable that the dielectric constant of the insulating film of the capacitor is higher than the dielectric constant of the insulating film that is a component of the switching element.
According to the present invention, the capacitance per unit area of the electrostatic protection capacitor can be increased. Therefore, the protection effect against static electricity can be enhanced while reducing the area occupied by the electrostatic protection capacitor.

In the electro-optical device according to the aspect of the invention, it is preferable that the common electrode line is disposed along the outer periphery of the electro-optical device.
According to the present invention, when a capacitor for electrostatic protection is disposed on the outer periphery of the electro-optical device, the distance between the capacitor and the common electrode line can be shortened. Therefore, the present invention can further enhance the protection effect against static electricity. Here, the distance between the electrostatic protection capacitor and the gate line or the data line is preferably short.

In order to achieve the above object, an electronic apparatus according to an aspect of the invention includes the electro-optical device.
According to the present invention, it is possible to provide an electronic device having high resistance to static electricity, inexpensive and high performance.

  Hereinafter, an electro-optical device and an electronic apparatus according to an embodiment of the invention will be described with reference to the drawings. In the embodiments described below, a display unit (matrix structure) of a liquid crystal display device is given as an example of an electro-optical device.

  FIG. 1 is a circuit diagram illustrating an example of an electro-optical device according to an embodiment of the invention. The matrix structure (electro-optical device) 100 forms a display portion of an active matrix type liquid crystal display device driven by TFTs. In the matrix structure 100, a plurality of data lines 3a, 3b, 3c arranged in the Y-axis direction and a plurality of gate lines 4a, 4b, 4c arranged in the X-axis direction intersect in a lattice pattern. It has a structure. A TFT (switching element) 2 is arranged at each intersection of the data lines 3a, 3b, 3c and the gate lines 4a, 4b, 4c in the matrix structure 100. The TFT 2 is a switching element and controls signal transmission between the data lines 3a, 3b and 3c and the liquid crystal pixel 1 which is a driving element. The TFT 2 is an n-channel TFT, for example. The data line 3a, 3b, 3c is electrically connected to the source of the TFT 2 disposed in the vicinity of the data line 3a, 3b, 3c. The gates of the TFTs 2 disposed in the vicinity of the gate lines 4a, 4b, and 4c are electrically connected to the gate lines 4a, 4b, and 4c.

  Further, a liquid crystal pixel (driving element) 1 is arranged at each intersection of the data lines 3a, 3b, 3c and the gate lines 4a, 4b, 4c in the matrix structure 100. The liquid crystal pixel 1 serves as a driving element driven by a signal flowing through the TFT 2. The liquid crystal pixel 1 has a configuration in which the liquid crystal is sandwiched between the pixel electrode 1a and the counter electrode 1b. The pixel electrode 1a is electrically connected to the drain of the TFT2. A reference potential (for example, 0 volts or several volts) is applied to the counter electrode 1b. In the matrix structure 100, the liquid crystal is not partitioned for each pixel. That is, the liquid crystal is interposed without being partitioned in the entire display region of the matrix structure 100 and is sandwiched between a pair of substrates.

  In the matrix structure 100 having such a configuration, a plurality of liquid crystal pixels 1 whose display states such as light and dark are driven and controlled by the TFTs 2 are arranged like a grid, and an image having a desired shape can be displayed. In the image display, image signals (data signals) are supplied to the data lines 3a, 3b, 3c, and scanning signals are supplied to the gate lines 4a, 4b, 4c. For example, each of the TFTs 2 is turned on (conductive state) for a certain period by a pulsed scanning signal sequentially applied to the gate lines 4a, 4b, and 4c. During this fixed period, the image signal applied to the data lines 3a, 3b, 3c is applied to the pixel electrode 1a through the TFT 2. The image signal (potential) applied to the pixel electrode 1a is held in the liquid crystal pixel 1 for a certain period. The liquid crystal sandwiched between the pixel electrode 1a and the counter electrode 1b changes the orientation and order of the molecular assembly depending on the applied voltage level, modulates the light transmittance, and enables gradation display. As a result, the liquid crystal pixel 1 has substantially constant brightness according to the image signal for a certain period.

  For example, it is assumed that the matrix structure 100 forms a normally white display unit. Then, when the level of the image signal is zero, the liquid crystal pixel 1 is displayed in white (minimum state). When the level of the image signal is the maximum level, the liquid crystal pixel 1 is displayed in black (maximum state). When the level of the image signal is an intermediate level, the liquid crystal pixel 1 is displayed in gray (halftone). In FIG. 1, a data line driving circuit for supplying an image signal and a gate line driving circuit for supplying a scanning signal are not shown. Further, a color image is displayed by overlaying a color filter on each liquid crystal pixel 1.

  Furthermore, the matrix structure 100 of the present embodiment includes a common electrode line 5 and a capacitor C. The common electrode line 5 is a linear conductor having a reference potential. Here, the reference potential may mean, for example, a reference potential (Signal Ground) of an image signal or a scanning signal, or may mean a case ground (Frame Ground). The common electrode line 5 may be disposed along the outer periphery of the matrix structure 100.

  The capacitor C is disposed between the gate lines 4a, 4b, 4c and the common electrode line 5, and between the data lines 3a, 3b, 3c and the common electrode line 5, respectively. That is, one terminal of the capacitor C is connected to any one of the data lines 3 a, 3 b, 3 c or the gate lines 4 a, 4 b, 4 c, and the other terminal of the capacitor C is connected to the common electrode line 5. Note that the wiring connecting the terminal of the capacitor C and the data lines 3a, 3b, 3c or the gate lines 4a, 4b, 4c is preferably as short as possible. Further, it is preferable that the wiring connecting the terminal of the capacitor C and the common electrode line 5 is as short as possible.

  The capacitor C arranged in this way protects components such as the TFT 2 of the matrix structure 100 from electrostatic breakdown. For example, when static electricity enters the gate line 4a of the matrix structure 100, the potential of the gate line 4a may instantaneously rise to about 1000 volts. However, the electrostatic charge that has entered the gate line 4 a first passes through the conductor forming the gate line 4 a and then enters the capacitor C that is disposed between the gate line 4 a and the common electrode line 5. Then, the potential of the gate line 4a rapidly decreases and becomes equal to or lower than the withstand voltage (for example, 100 volts) of the TFT2. Here, the time required for the electrostatic charge to enter the capacitor C through the conductor is shorter than the time required to pass through the gate insulating film of the TFT 2. From these, the potential of the gate line 4a is lowered before the TFT 2 is destroyed due to electrostatic charges passing between the gate of the TFT 2 and the source or drain.

  As a result, the matrix structure 100 of the present embodiment can more reliably avoid the destruction of the components such as the TFT 2 due to static electricity by the capacitor C as compared with the conventional case. Therefore, according to the present embodiment, the matrix structure 100 that is resistant to static electricity can be provided at low cost.

The capacity of the capacitor C is the first capacity or the second capacity when the capacity between the gate and the source of one TFT 2 is the first capacity and the capacity between the gate and the drain of the TFT 2 is the second capacity. It is preferable that it is 10 times or more. This is equivalent to increasing the first capacitance and the second capacitance of one TFT 2 by the capacitance of the capacitor C with respect to the electrostatic potential (signal). That is, the first capacitor and the second capacitor (C) of the TFT 2 are 10 times or more. The relationship between the electrostatic charge Q (coulomb), the capacitance C (farad) and the voltage V (volt) is V = Q / C
It is. Therefore, the matrix structure 100 of the present embodiment can reduce an excessive voltage of static electricity (for example, 1000 volts) to 1/10 or less (100 volts or less).

  The capacitance of the capacitor C is preferably a capacitance that does not change the content of the signal applied to the gate lines 4a, 4b, 4c or the data lines 3a, 3b, 3c to which one end of the capacitor is connected. In other words, the capacitance of the capacitor C connected to the data lines 3a, 3b, 3c is preferably a capacitance that does not change the content of the image signal. Further, the capacitance of the capacitor C connected to the gate lines 4a, 4b, 4c is preferably a capacitance that does not change the content of the scanning signal.

  Specifically, for example, the capacitance of the capacitor C connected to one data line 3a, 3b, 3c is the first of the plurality of TFTs 2 connected to the one data line 3a, 3b, 3c. It is preferably 50% or less (or 5 to 30%) of the total of the capacity or the second capacity. More specifically, the capacitance of the capacitor C connected to one data line 3a, 3b, 3c is the first capacitance of the plurality of TFTs 2 connected to the one data line 3a, 3b, 3c. Alternatively, it is preferably about 10 percent of the total of the second capacity.

  The capacitance of the capacitor C connected to the single gate line 4a, 4b, 4c is the first capacitance or the second capacitance of the plurality of TFTs 2 connected to the single gate line 4a, 4b, 4c. It is preferable that it is 50 percent or less (or 5 to 30 percent) of the total of the above. More specifically, the capacitance of the capacitor C connected to one gate line 4a, 4b, 4c is the first capacitance of the plurality of TFTs 2 connected to the one gate line 4a, 4b, 4c. Alternatively, it is preferably about 10 percent of the total of the second capacity.

Consider the case where the capacitance of the capacitor C is 10% of the total of the first capacitance or the second capacitance of the plurality of TFTs 2 connected to one gate line or data line. Then, for example, when 200 TFTs 2 are connected to one gate line 4a, 4b, 4c, a capacitance of 200C obtained by multiplying the first capacitor or the second capacitor (C) of one TFT 2 by 200 is obtained. One gate line 4a, 4b, 4c has. Then, assuming that the capacity of the capacitor is 10% of 200C, when one capacitor C is connected to one gate line 4a, 4b, 4c,
{200C + 200C × 0.1} = 220C
That is, one gate line 4a, 4b, 4c has the above-mentioned capacitance. Therefore, since the increase in the capacitance of the entire gate lines 4a, 4b, 4c due to the connection of the capacitor C to the gate lines 4a, 4b, 4c is 10%, the capacitor C is connected to the gate lines 4a, 4b, 4c. It is possible to avoid affecting the original scanning signal to be applied.

Here, the scanning signal or the image signal is supplied to all the TFTs 2 connected to one data line 3a, 3b, 3c or gate line 4a, 4b, 4c. It is empirically considered that the influence is exerted on one TFT 2. Therefore, in the case of the one gate line 4a, 4b, 4c described above, the capacitance of one TFT 2 is reduced by the capacitor C against the electrostatic voltage.
{C + 200C × 0.1} = 21C
It becomes. Therefore, the capacitance of the TFT 2 is increased about 21 times by the capacitor C against static electricity.

  As a result, the matrix structure 100 of the present embodiment can accurately execute the original operation by the scanning signal and the image signal by adding the capacitor C to the original configuration, and avoids the breakdown due to static electricity. Can do. The waveform of the scanning signal or image signal may be set in advance in consideration of the influence of the capacitance of the capacitor C on the scanning signal or image signal.

  FIG. 2 is a circuit diagram showing an example of a matrix structure 200 according to another embodiment of the present invention. In FIG. 2, the same components as those in FIG. In the matrix structure 200, a plurality of capacitors 2 are arranged near the outer periphery of the matrix structure 200. The common electrode line 5 is disposed on the outer periphery (four sides) of the matrix structure 200. The plurality of capacitors 2 are arranged inside the common electrode line 5 in the matrix structure 200 and in the vicinity of the common electrode line 5. Therefore, the plurality of capacitors 2 are arranged at almost equal intervals in the vicinity of the four sides of the matrix structure 200.

  Moreover, it is preferable that the capacitor | condenser 2 is arrange | positioned in the position which overlaps with the formation area of what is called a peripheral parting. Here, the peripheral parting is an area arranged so as to surround the periphery of the display area (arrangement area of the liquid crystal pixels 1) in the matrix structure 200, for example, an area where a member made of a light shielding material is arranged. Note that the gate line driving circuit 20 and the data line driving circuit 30 shown in FIG. 2 may be constituent elements of the matrix structure 200, or may be constituent elements that are not included in the matrix structure 200 (other liquid crystal display devices). . The gate line driving circuit 20 outputs a scanning signal to the gate lines 4a, 4b, 4c. The data line driving circuit 30 outputs image signals to the data lines 3a, 3b, 3c.

  Thus, according to the matrix structure 200, the arrangement of the original components arranged in the display area such as the data lines 3a, 3b, 3c, the gate lines 4a, 4b, 4c, the common electrode line 5, and the TFT 2 is affected. A plurality of capacitors 2 for electrostatic protection can be arranged without any problem. Therefore, according to the present embodiment, electrostatic breakdown can be effectively prevented while maintaining the high density arrangement of the original components in the display area of the matrix structure 200. Therefore, by using the matrix structure 200, an image can be displayed with high quality, and a liquid crystal display device with high resistance to static electricity, high reliability, and long life can be provided at low cost.

  In the matrix structure 200 of the present embodiment, the common electrode lines 5 are arranged along the outer periphery of the matrix structure 200. Thereby, the distance between the capacitor C and the common electrode line 5 can be shortened. Therefore, the matrix structure 200 can further enhance the protection effect against static electricity. The distance between the capacitor C and the data lines 3a, 3b, 3c or the gate lines 4a, 4b, 4c is preferably short.

(Liquid crystal display device)
FIG. 3 is a plan view showing a main part of the liquid crystal display device according to the embodiment of the present invention. The main part of this liquid crystal display device has the matrix structure 100 of the above embodiment. In FIG. 3, the same components as those shown in FIG.

  The main part of the liquid crystal display device includes a TFT array substrate 7 having a configuration corresponding to the matrix structure 100. As shown in FIG. 3, a plurality of pixel electrodes 1a (contours are indicated by broken lines) made of a transparent conductive film such as indium tin oxide (hereinafter abbreviated as ITO) on the TFT array substrate 7. ) Are arranged in a matrix, and data lines 3 (the outline is indicated by a two-dot chain line) are provided along the side of the pixel electrode 1a that extends in the vertical direction on the paper surface. (Scanning line) 4 and capacitive line 6 (both contours are indicated by solid lines) are provided.

  In the main part of the present liquid crystal display device, the gate line 4 includes a main gate line 4A intersecting with the plurality of data lines 3, and a branch gate line 4B extending from the main gate line 4A, and a polysilicon film. An L-shaped portion 8a intersecting the branch gate line 4B and the main gate line 4A is formed in the semiconductor layer (first capacitor electrode) 8 (contour is indicated by a one-dot chain line). That is, the L-shaped portion 8a intersects the main gate line 4A and the branch gate line 4B to form two channel regions.

  Contact holes 9 and 10 are formed at both ends of the L-shaped portion 8a of the semiconductor layer 8, and one contact hole 9 serves as a source contact hole that electrically connects the data line 3 and the source region of the semiconductor layer 8, and the other The contact hole 10 is a drain contact hole that electrically connects the drain electrode 11 (the outline is indicated by a two-dot chain line) and the drain region of the semiconductor layer 8. That is, the source contact hole 9 and the drain contact hole 10 are disposed on opposite sides of the gate line 4. Further, a pixel contact hole 12 for electrically connecting the drain electrode 11 and the pixel electrode 1a is formed at the end of the drain electrode 11 opposite to the side where the drain contact hole 10 is provided. .

  The TFT 2 in the main part of the present liquid crystal display device intersects the main gate line 4A and the branch gate line 4B at the L-shaped portion 8a of the semiconductor layer 8, and the semiconductor layer 8 and the gate line 4 intersect twice. Therefore, a TFT having two gates on one semiconductor layer, a so-called dual gate type TFT is formed. Further, the capacitor line 6 extends along the gate line 4 so as to pass through pixels arranged in the horizontal direction on the paper surface, and a branched part 6 a extends along the data line 3 in the vertical direction on the paper surface. Therefore, the storage capacitor 5 is formed by the semiconductor layer 8 and the capacitor line 6 along the data line 3. In the present embodiment, half of the branch gate line 4B is covered with the wide portion 3A in which the width of the data line 3 is increased, thereby suppressing light from entering the channel region of this portion.

  FIG. 4 is a diagram showing a cross-sectional structure of the TFT array substrate 7. As shown in FIG. 4, the TFT array substrate 7 has a glass substrate 41 as a supporting substrate, and the TFT 2 is formed on the inner surface via a base insulating film 42. The TFT 2 includes a gate line 4, a channel region 50 of the semiconductor layer 8 in which a channel is formed by an electric field from the gate line 4, a gate insulating film 44 that is an insulating thin film that insulates the gate line 4 and the semiconductor layer 8, data Line 3, source region 49 and drain region 51 of semiconductor layer 8 are provided.

  Further, on the glass substrate 41 including the gate line 4 and the gate insulating film 44, the first interlayer insulating layer 52 in which the source contact hole 9 leading to the source region 49 and the drain contact hole 10 leading to the drain region 51 are respectively formed. Is formed. That is, the data line 3 is electrically connected to the source region 49 through the source contact hole 9 that penetrates the first interlayer insulating layer 52. Further, a second interlayer insulating layer 53 in which the drain contact hole 10 leading to the drain region 51 is formed is formed on the data line 3 and the first interlayer insulating layer 51. That is, the drain region 51 is electrically connected to the drain electrode 11 and the pixel electrode 1a through the drain contact hole 10 penetrating the first interlayer insulating layer 52 and the second interlayer insulating layer 53. Further, an alignment film 54 that has been subjected to an alignment process in a certain rubbing direction Y by a rubbing process is provided on the second interlayer insulating layer 53 and the pixel electrode 1a. The alignment film 54 is a horizontal alignment film made of a polyimide-based polymer resin.

  The wide portion (light shielding layer) 3A and the capacitor line (light shielding layer) 6 function as a so-called black matrix that shields light from areas other than the display area of each pixel. That is, the wide portion 3A and the capacitor line 6 have a function of hiding the disclination portion, and incident light from the counter substrate 15 side enters the channel region 50, the source region 49, the drain region 51, and the like in the semiconductor layer 8 of the TFT 2. In addition to preventing intrusion, it has functions such as improving the contrast ratio and preventing color mixing of the color filter color material.

  In the main part of the present liquid crystal display device, the overlapping part (hatched part in FIG. 3) of the wide part 3A and the capacitor line 6 and the pixel electrode 1a is located on the opposite side of the rubbing direction Y in the peripheral part of the pixel electrode 1a. A region overlapping with the peripheral portion (region where the disclination is large) is formed wider than the peripheral portion (region where the disclination is small) on the forward direction side in the rubbing direction Y. That is, the width of the overlapping portion b is wider than that of the overlapping portion a, and the width of the overlapping portion c is set wider than that of the overlapping portion d, so that the overlapping portion is asymmetric on the left and right and top and bottom. Note that the widths of these overlapping portions a, b, c, and d are determined according to the range of disclination that occurs in those portions.

  FIG. 5 is a plan view showing the overall configuration of the liquid crystal display device 40 having the TFT array substrate 7. That is, FIG. 5 shows an overall configuration of a liquid crystal display device 40 according to an application example of the present embodiment. 6 is a cross-sectional view of the liquid crystal display device 40 shown in FIG. The liquid crystal display device 40 has a configuration in which the liquid crystal layer 116 is sandwiched between the TFT array substrate 7 and the counter substrate 15.

  5 and 6, a sealing material 28 is provided on the TFT array substrate 7 along the edge thereof, and a light shielding film 29 as a frame is provided in parallel to the inside thereof. The region where the light shielding film 29 is provided corresponds to the “peripheral parting” region, and the capacitor C shown in FIGS. 1 and 2 is arranged at a position overlapping the light shielding film 29.

  A data line driving circuit 130 and an external circuit connection terminal 31 are provided along one side of the TFT array substrate 7 in a region outside the sealing material 28, and the gate line driving circuit 32 is provided on two sides adjacent to the one side. It is provided along. Needless to say, if the delay of the scanning signal supplied to the gate line 4 does not become a problem, the gate line driving circuit 32 may be only on one side. Further, the data line driving circuit 130 may be arranged on both sides along the side of the image display area. For example, the odd-numbered data lines 3 supply an image signal from a data line driving circuit disposed along one side of the image display area, and the even-numbered data lines 3 are on the opposite side of the image display area. The image signal may be supplied from a data line driving circuit arranged along the line. If the data lines 3 are driven in a comb shape in this way, the area occupied by the data line driving circuit can be expanded, and a complicated circuit can be configured. Further, on the remaining side of the TFT array substrate 7, a plurality of wirings 33 are provided for connecting between the gate line driving circuits 32 provided on both sides of the image display area. In addition, a conductive material 34 for providing electrical continuity between the TFT array substrate 7 and the counter substrate 15 is provided in at least one corner of the counter substrate 15 on which the counter electrode is formed inside. . The counter substrate 15 having substantially the same outline as the sealing material 28 is fixed to the TFT array substrate 7 by the sealing material 28.

  In the present liquid crystal display device 40, in the overlapping portion of the wide portion 3A and the capacitor line 6 and the pixel electrode 1a, the region overlapping the peripheral portion on the opposite side of the rubbing direction Y in the peripheral portion of the pixel electrode 1a is in the rubbing direction Y. Since it is formed wider than the area overlapping the forward direction side, an appropriate size black matrix (overlapping part) is arranged according to the size of disclination determined by the rubbing direction, and disclination from the opening Can be prevented, and the aperture ratio can be improved by not shielding light more than necessary in a portion where the disclination is small.

  In the liquid crystal display device 40, the wide portion 3A and the capacitor line 6 which are part of the data line 3 are used as the light shielding layer, but a light shielding layer may be provided separately from these. For example, a black matrix may be formed inside the counter substrate 15. However, if the wide portion 3A of the data line 3 and the capacitor line 6 function as a black matrix as in the present liquid crystal display device 40, it is not necessary to separately provide a light shielding layer serving as a black matrix on the counter substrate 15 or the like. Simplification of the structure and reduction of manufacturing processes can be achieved.

  Further, in the manufacturing process of the TFT array substrate 7 which is a component of the liquid crystal display device 40, the capacitor C may be formed in the TFT 2 forming process. For example, it is assumed that the capacitor C is composed of a pair of first and second electrodes facing each other and an insulating film sandwiched between the first electrode and the second electrode. The first electrode of the capacitor C is the same layer as the gate line 4, and the first line of the capacitor C may be formed by etching or the like to form the gate line 4 at the same time. . In addition, the insulating film of the capacitor C is the same layer as the gate insulating film 44, and the insulating film of the capacitor C may be formed by etching or the like to form the gate insulating film 44 at the same time. . The second electrode of the capacitor C is the same layer as the drain electrode 11 (or the wide portion 3A or the data line 3). The drain electrode 11 is formed by etching the layer, and at the same time, the etching of the capacitor C is performed. A second electrode may be formed.

  In this way, the first electrode of the capacitor C is made of the same constituent material as the gate line 4 of the TFT 2, the insulating film of the capacitor C is made of the same constituent material as the gate insulating film 44 of the TFT 2, and the second electrode of the capacitor C is made. The electrode is made of the same material as that of the drain electrode 11 of the TFT 2. Therefore, the capacitor C for electrostatic protection can be formed in the process of forming the TFT 2. Therefore, it is possible to provide the liquid crystal display device 40 that is resistant to static electricity while suppressing an increase in manufacturing cost.

  The first electrode of the capacitor C has the same thickness as the gate line 4, the insulating film of the capacitor C has the same thickness as the gate insulating film 44, and the second electrode of the capacitor C is the same as the drain electrode 11. It is good also as it being the film thickness of. In this way, in the formation of the electrostatic protection capacitor C, it is not necessary to add another etching process or the like to the formation process of the TFT 2 in order to adjust the thicknesses of the first electrode, the second electrode, and the insulating film. It becomes. Therefore, it is possible to provide a liquid crystal display device 40 that is more inexpensive and resistant to static electricity.

  Further, the insulating film of the capacitor C may be formed of a layer different from the gate insulating film 44. In this case, the dielectric constant of the insulating film of the capacitor C is preferably higher than the dielectric constant of the gate insulating film 44. In this way, the capacitor C can be made compact and the capacity can be increased, and a compact and high-performance liquid crystal display device 40 can be provided.

(Electronics)
Next, another electronic device having the liquid crystal display device 40 of the above embodiment as a component will be described.
FIG. 7A is a perspective view showing an example of a mobile phone. In FIG. 7A, reference numeral 500 indicates a mobile phone body, and reference numeral 501 indicates a display unit having the liquid crystal display device 40 of the above embodiment. FIG. 7B is a perspective view showing an example of a wristwatch type electronic device. In FIG. 7B, reference numeral 600 denotes a watch body, and reference numeral 601 denotes a display unit having the liquid crystal display device 40 of the above embodiment. FIG. 7C is a perspective view illustrating an example of a portable information processing apparatus such as a word processor or a personal computer. In FIG. 7C, reference numeral 700 denotes an information processing apparatus, reference numeral 701 denotes an input unit such as a keyboard, reference numeral 702 denotes a display unit including the liquid crystal display device 40 of the above embodiment, and reference numeral 703 denotes an information processing apparatus main body. Show.

  Since the electronic device shown in FIG. 7 has the liquid crystal display device 40 of the above-described embodiment, the electronic device has high resistance to static electricity, can be inexpensive, and has high performance.

  The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention, and the specific materials and configurations described in the embodiment. These are merely examples, and can be changed as appropriate.

  For example, in the above-described embodiment, the electro-optical device (matrix structure) has been described as being used in a liquid crystal display device. However, the present invention is not limited to this, and various devices including the electro-optical device. Can be applied to. Examples of the application target of the electro-optical device and the electronic apparatus according to the present invention include an electro-optical device such as an organic electroluminescence display device, a memory integrated circuit including a complementary metal oxide semiconductor (CMOS), or an imaging element integrated circuit.

  In the above embodiment, a normally white liquid crystal display device has been described. However, the present invention can also be applied to a normally black display device. Further, in the matrix structures 100 and 200 of the above embodiment, the common electrode line 5 is cited as a connection target of one terminal of the capacitor C. The present invention is not limited to this, and one terminal of the capacitor C may be connected to a conductor other than the common electrode line 5.

1 is a circuit diagram showing a matrix structure (electro-optical device) according to an embodiment of the present invention. It is a circuit diagram which shows the matrix structure which concerns on other embodiment of this invention. It is a principal part top view of the liquid crystal display device which concerns on embodiment of this invention. It is principal part sectional drawing of a liquid crystal display device same as the above. It is a whole top view of a liquid crystal display device same as the above. It is a whole sectional view of a liquid crystal display same as the above. It is a figure which shows an example of the electronic device which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Liquid crystal pixel, 1a ... Pixel electrode, 1b ... Counter electrode, 2 ... TFT, 3a, 3b, 3c ... Data line, 4a, 4b, 4c ... Gate line (scanning line), 5 ... Common electrode line, 100, 200 ... Matrix structure (electro-optical device), capacitor ... C

Claims (15)

A plurality of gate lines arranged in the X-axis direction and a plurality of data lines arranged in the Y-axis direction cross each other;
Switching elements arranged at the intersections;
A pixel electrode disposed corresponding to the switching element;
A common electrode line to be a reference potential;
An electro-optical device comprising a capacitor disposed between at least one of the gate line and the common electrode line and between the data line and the common electrode line.   The electro-optical device according to claim 1, wherein the capacitor protects components of the electro-optical device from electrostatic breakdown.   The capacitance of the capacitor is the first capacitance or the capacitance when the capacitance between the control end and the input end of the switching element is a first capacitance and the capacitance between the control end and the output end of the switching element is a second capacitance. The electro-optical device according to claim 1, wherein the electro-optical device has 10 times or more the second capacity.   4. The capacitor according to claim 1, wherein the capacitor has a capacitance that does not change a content of a signal applied to the gate line or the data line to which one end of the capacitor is connected. 5. The electro-optical device described.   The capacity of the capacitor connected to one gate line or data line is the sum of the first capacity or second capacity of the plurality of switching elements connected to the one gate line or data line. 5. The electro-optical device according to claim 3, wherein the electro-optical device is 50% or less.   The capacitance of the capacitor connected to one gate line or data line is equal to the first capacitance or the second capacitance of the plurality of switching elements connected to the one gate line or data line. 5. The electro-optical device according to claim 3, wherein the total amount is in a range of 5 to 30 percent.   The electro-optical device according to claim 1, wherein the capacitor is disposed near an outer periphery of the electro-optical device. The electro-optical device is a component of a liquid crystal display device,
The drive element is a pixel having a liquid crystal sandwiched between the pixel electrode and a counter electrode,
The switching element is a thin film transistor,
A gate of the thin film transistor is connected to the gate line;
8. The electricity according to claim 1, wherein the thin film transistor supplies a signal from the data line to the pixel electrode based on a signal supplied to the gate line. Optical device.   The electro-optical device according to claim 8, wherein the capacitor is disposed so as to overlap a peripheral parting disposed around a display area of the liquid crystal display device.   10. The electro-optical device according to claim 8, wherein the capacitor is formed in the thin film transistor forming step. The capacitor includes a pair of first and second electrodes facing each other, and an insulating film sandwiched between the first electrode and the second electrode,
The first electrode of the capacitor is made of the same constituent material as the gate electrode of the thin film transistor,
The capacitor insulating film is made of the same material as the gate insulating film of the thin film transistor,
11. The electro-optical device according to claim 8, wherein the second electrode of the capacitor is made of the same material as that of the source electrode or the drain electrode of the thin film transistor. The capacitor includes a pair of first and second electrodes facing each other, and an insulating film sandwiched between the first electrode and the second electrode,
The first electrode of the capacitor has the same film thickness as the gate electrode of the thin film transistor,
The insulating film of the capacitor has the same thickness as the gate insulating film of the thin film transistor,
12. The electro-optical device according to claim 8, wherein the second electrode of the capacitor has the same film thickness as a source electrode or a drain electrode of the thin film transistor.   13. The electro-optical device according to claim 1, wherein a dielectric constant of the insulating film of the capacitor is higher than a dielectric constant of an insulating film that is a component of the switching element.   The electro-optical device according to claim 1, wherein the common electrode line is disposed along an outer periphery of the electro-optical device. An electronic apparatus comprising the electro-optical device according to claim 1.

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