JP2004151345A - Inspection circuit, electrooptical panel and electronic appliance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the leakage amount of an inspection circuit and to reduce a circuit scale. <P>SOLUTION: Analog switches ASW5-ASW7 are connected between data lines 3-1 - 3-3 and inspection lines T1-T3. In inspection, the analog switches ASW1 and ASW2 are turned on and selection signals SEL and inverted selection signals SELX are supplied to the control terminals of the analog switches ASW5-ASW7. In non-inspection, while the analog switches ASW1 and ASW2 are turned off, since the control terminals of the analog switches ASW5-ASW7 are connected through the analog switches ASW3 and ASW4 to a high potential power source VDD or a low potential power source VSS, the analog switches ASW5-ASW7 are surely turned off. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention belongs to a technical field related to inspection of an electro-optical panel.
[0002]
[Prior art]
The liquid crystal panel includes an element substrate and a counter substrate. While a common electrode is formed on the opposing substrate, an inspection circuit may be provided on the element substrate for inspecting disconnection and short-circuit of the data line in addition to the scanning line and the data line. And Patent Document 2).
[0003]
FIG. 10 is a block diagram of an element substrate provided with an inspection circuit. A plurality of scanning lines 2 and a plurality of data lines 3 are formed on the element substrate. Then, each pixel P is formed in a matrix corresponding to the intersection of the scanning line 2 and the data line 3. One end of the data line 3 is connected to the sampling switch SW, and the other end is connected to the inspection circuit 300D.
[0004]
The inspection circuit 300D includes an analog switch SWA and an analog switch SWB. The control signal C is supplied to the analog switch SWB, and when the analog switch SWB is turned on, the inspection circuit and the data line 3 are connected. On the other hand, when the analog switch SWB is turned off, the test circuit 300D and the data line 3 are disconnected. The inspection of the data line 3 is performed with the analog switch SWB turned on, and the analog switch SWB is turned off in a normal operation state.
[0005]
The selection signal S is supplied to the control terminal of the analog switch SWA, and the inspection line and the data line 3 are connected during the active period of the selection signal. At this time, by turning on the sampling switch SW, a path of the inspection line → the analog switch SWA → the analog switch SWB → the data line 3 → the sampling switch SW → the signal line is formed. The disconnection can be known through this route.
[0006]
[Patent Document 1]
JP-A-11-271806 (FIGS. 5 and 6)
[0007]
[Patent Document 2]
JP-A-5-307167 (FIG. 1)
[0008]
[Problems to be solved by the invention]
In image display on a liquid crystal panel, when a scanning signal is applied via a scanning line, each TFT connected to the scanning line is turned on. When each sampling switch is sequentially turned on during a period in which a certain scanning line is selected, an image signal is sequentially applied to each pixel electrode via each data line, and the pixel electrode and the common electrode (common electrode) are turned on. Predetermined charges are accumulated in the liquid crystal layer between them. Then, when the sampling switch SW is turned off and the scanning signal becomes inactive, the writing is completed. Such a scanning method is called a dot sequential method.
[0009]
In the dot sequential method, there is a time lag between the time when the voltage of the signal line is sampled by the sampling switch SW and the time when the scanning signal becomes inactive and writing is completed. During this period, electric charge may leak between the data line and the test circuit 300D, and the write voltage may fluctuate. The amount of leakage between the data line and the test circuit increases as the off-resistance of the analog switches SWA and SWB decreases. The off resistance depends on the potential difference between the source and the drain of the TFT forming the switch. At the time of non-inspection, the inspection circuit side is in a floating state from the inspection circuit side terminal of the analog switch SWB, and its potential is not determined. Therefore, the conventional liquid crystal panel has a problem that the amount of leak increases and the quality of the displayed image deteriorates.
[0010]
Further, when a DC voltage is applied to the liquid crystal, the composition changes and so-called burning occurs. Therefore, the liquid crystal is generally driven by an AC drive in which an AC voltage is applied to drive the liquid crystal. The AC driving includes a method of inverting the potential of the data line at a predetermined cycle while keeping the potential of the common electrode constant, and a method of inverting the potential of the common electrode at a predetermined cycle. In particular, when the latter driving method is adopted, there is a problem that the potential difference between the source and the drain of the TFT constituting the analog switch SWB becomes large, and the leakage amount becomes large.
[0011]
Further, at the time of inspection, it is necessary to reduce the resistance values of the analog switches SWA and SWB, but it is necessary to increase the channel width of the transistors constituting the analog switches SWA and SWB, and the circuit scale of the inspection circuit becomes large. There was a problem.
[0012]
The present invention has been made in view of the above-described circumstances, and has as its object to provide an inspection circuit, an electro-optical panel, and the like that can suppress the amount of charge leakage with a simple configuration.
[0013]
[Means for Solving the Problems]
In order to solve the above problem, an inspection circuit according to the present invention includes a plurality of scanning lines, a plurality of data lines, and switching elements arranged in a matrix corresponding to intersections of the scanning lines and the data lines. An inspection line for supplying an inspection signal, a separation switch connected between the scanning line or the data line and the inspection line, and a selection signal for one of the following. A selection switch that is supplied to an input / output terminal and the other input / output terminal is connected to a control terminal of the separation switch via a signal line, and is connected to a control terminal of the selection switch, and turns on the selection switch during inspection. A control line for supplying a control signal for turning off the selection switch at the time of non-inspection, a wiring to which a potential for turning off the separation switch is supplied, and the signal line; The switch comprises an auxiliary switch for exclusively on and off.
[0014]
According to the present invention, since the inspection signal is supplied to the scanning line or the data line via the separation switch, the on-resistance value can be reduced. Further, the auxiliary switch is turned on / off exclusively with the selection switch, and thus is turned on at the time of non-inspection in which the selection switch is turned off. For this reason, the potential of the signal line at the time of non-inspection is a potential for turning off the separation switch. Therefore, the control terminal of the separation switch does not enter a floating state at the time of non-inspection, and the separation switch is reliably turned off. This makes it possible to reduce the amount of leakage of charges flowing into the inspection circuit. Further, the selection switch and the auxiliary switch only need to control the potential of the control terminal of the separation switch, and the inspection signal does not flow there. Therefore, the size of the transistors constituting the selection switch and the auxiliary switch may be extremely small. Thereby, the circuit scale of the inspection circuit can be significantly reduced. Note that the separation switch, the selection switch, and the auxiliary switch can be formed using the same elements as the switching elements, and for example, TFTs may be used.
[0015]
Here, it is preferable that the wiring is a power supply line for supplying power. Since the power supply line has low impedance, the separation switch can be reliably turned off. Preferably, the wiring is the control line. In this case, the control line and the wiring can be shared, and the circuit scale of the inspection circuit can be reduced.
[0016]
In addition, it is preferable that the above-described test circuit includes a test line switch connected between a potential line to which a predetermined potential is supplied and the test line and turned off during a test and turned on during a non-test. In this case, since a predetermined potential can be supplied to the inspection line at the time of non-inspection, it is possible to reduce the amount of leakage of the charge flowing into the inspection circuit.
[0017]
Here, a control terminal of the inspection line switch is preferably connected to the control line. In this case, since a control signal can be supplied to the inspection line switch via the control line, there is no need to separately provide a wiring, and the circuit scale can be reduced.
[0018]
Next, another inspection circuit according to the present invention includes a plurality of scanning lines, a plurality of data lines, and switching elements arranged in a matrix corresponding to intersections of the scanning lines and the data lines. It is used for an electro-optical panel and is connected between an inspection line for supplying an inspection signal and the scanning line or the data line and the inspection line, and is turned on at the time of inspection and turned off at the time of non-inspection. An isolation switch and a test line switch connected between a potential line to which a predetermined potential is supplied and the test line and turned off during a test and turned on during a non-test. According to the present invention, it is possible to supply a predetermined potential to the inspection line at the time of non-inspection, so that it is possible to reduce the amount of charge leakage flowing into the inspection circuit.
[0019]
The above-described inspection circuit includes an element substrate on which the plurality of scanning lines, the plurality of data lines, and the switching element are formed, a counter substrate having a common electrode, and an electric circuit between the element substrate and the counter substrate. If it is used for an electro-optical panel sandwiching an optical substance, it is desirable that the predetermined potential is the potential of the common electrode. The composition of an electro-optical material such as a liquid crystal changes when a DC voltage is applied, and so-called burn-in occurs. For this reason, it is usual to drive by AC drive which inverts an applied voltage. The AC driving includes a method of inverting the potential of the common electrode at a predetermined cycle around a reference potential, and a method of fixing the potential of the common electrode and inverting the polarity of an image signal at a predetermined cycle around this potential. In either method, the potential of the common electrode becomes the center potential. On the other hand, the amount of charge leakage depends on the off resistance of the separation switch and the potential difference between the input and output terminals of the separation switch. According to the present invention, at the time of non-inspection, the potential of one input / output terminal of the separation switch can be set to the potential of the common electrode, so that the amount of leakage can be reduced. Here, the potential of the common electrode may be inverted at a predetermined cycle around a reference potential.
[0020]
Further, an electro-optical panel according to the present invention includes the above-described inspection circuit. Further, an electronic apparatus according to the present invention includes the above-described electro-optical panel. For example, a liquid crystal device, a viewfinder used for a video camera, a mobile phone, a notebook computer, a video projector, and the like correspond to the present invention.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
<1. First Embodiment>
<1-1: Overall Configuration of Liquid Crystal Device>
FIG. 1 is a block diagram illustrating the overall configuration of the liquid crystal device according to the embodiment. This liquid crystal device includes a liquid crystal panel AA, a timing generation circuit 400, and an image processing circuit 500. The liquid crystal panel AA includes a pixel region A, a scanning line driving circuit 100, a data line driving circuit 200, and an inspection circuit 300A on the element substrate.
[0022]
The input image data D supplied to the liquid crystal device is, for example, in a 3-bit parallel format. The timing generation circuit 400 generates a Y clock signal YCK, an inverted Y clock signal YCKB, an X clock signal XCK, an inverted X clock signal XCKB, a Y transfer start pulse DY, and an X transfer start pulse DX in synchronization with the input image data D. Then, the data is supplied to the scanning line driving circuit 100 and the data line driving circuit 200. Further, the timing generation circuit 400 generates and outputs various timing signals for controlling the image processing circuit 500.
[0023]
Here, the Y clock signal YCK specifies a period for selecting the scanning line 2, and the inverted Y clock signal YCKB is obtained by inverting the logic level of the Y clock signal YCK. The X clock signal XCK specifies a period for selecting the data line 3, and the inverted X clock signal XCKB is obtained by inverting the logic level of the X clock signal XCK.
[0024]
The image processing circuit 500 subjects the input image data D to gamma correction and the like in consideration of the light transmission characteristics of the liquid crystal panel AA, and then performs D / A conversion on the image data of each of the RGB colors to generate image signals R, G, and B. Is generated and supplied to the liquid crystal panel AA.
[0025]
Next, as shown in FIG. 1, m (m is a natural number of 2 or more) scanning lines 2 are arranged in the pixel area A in parallel along the X direction, while 3n ( (n is one or more natural numbers) data lines 3 are formed in parallel along the Y direction. In the vicinity of the intersection between the scanning line 2 and the data line 3, the gate of the TFT 50 is connected to the scanning line 2, the source of the TFT 50 is connected to the data line 3, and the drain of the TFT 50 is connected to the pixel electrode 6. Connected. Each pixel is composed of a pixel electrode 6, a common electrode (described later) formed on a counter substrate, and a liquid crystal sandwiched between these electrodes. As a result, the pixels are arranged in a matrix corresponding to each intersection of the scanning line 2 and the data line 3.
[0026]
The description returns to FIG. The scanning signals Y1, Y2,..., Ym are applied to each scanning line 2 to which the gate of the TFT 50 is connected in a pulsed line-sequential manner. Therefore, when a scanning signal is supplied to a certain scanning line 2, the TFT 50 connected to the scanning line is turned on, so that data line signals X1, X2,..., X3n supplied from the data line 3 at a predetermined timing. Are written in the corresponding pixels in order and are held for a predetermined period.
[0027]
Since the orientation and order of the liquid crystal molecules change according to the potential level applied to each pixel, gray scale display by light modulation becomes possible. For example, in a normally white mode, the amount of light passing through the liquid crystal is limited as the applied potential increases, while in a normally black mode, the amount of light passing through the liquid crystal is reduced as the applied potential increases. Then, light having a contrast according to the image signal is emitted for each pixel. For this reason, a predetermined display becomes possible. Further, in order to prevent the held image signal from leaking, a storage capacitor 51 is added in parallel with a liquid crystal capacitor formed between the pixel electrode 6 and the common electrode.
[0028]
<1-2: Configuration of inspection circuit>
FIG. 2 is a block diagram showing a configuration of the inspection circuit. As shown in this figure, the inspection circuit 300A is supplied with a start pulse SP, a clock signal CLK, an inverted clock signal CLKX, a control signal GC, an inverted control signal GCX, and first to third inspection signals TS1 to TS3. The control signal GC is at a high level during a test, and is at a low level during a non-test. The inversion control signal GCX is obtained by inverting the control signal GC. The first to third inspection signals TS1 to TS3 are supplied to the units U1 to Un via inspection lines T1 to T3.
[0029]
The test circuit 300A includes n units U1 to Un. Each of the units U1 to Un has the same configuration, and three data lines 3 are connected to each other. The unit U1 includes a unit shift circuit SR and first to seventh analog switches ASW1 to ASW7. The unit shift circuit SR of each of the units U1 to Un shifts the start pulse SP according to the clock signal CLK and the inverted clock signal CLKX to generate the selection signal SEL and the inverted selection signal SELX. The selection signal SEL is active at a high level. The inversion selection signal SELX is obtained by inverting the selection signal SELX, and becomes active at a low level. Then, during a period in which the selection signal SEL of a certain unit is at the high level, the inspection of the three data lines 3 connected to the unit is performed.
[0030]
A control signal GC is supplied to the non-inversion control terminals of the first and second analog switches ASW1 and ASW2, and an inversion control signal GCX is supplied to their inversion control terminals. Accordingly, the first and second analog switches ASW1 and ASW2 are turned on at the time of inspection, while the first and second analog switches ASW1 and ASW2 are turned off at the time of non-inspection. That is, the first and second analog switches ASW1 and ASW2 function as selection switches for supplying the selection signal SEL and the inverted selection signal SELX at the time of inspection.
[0031]
The first and second analog switches ASW1 and ASW2 are connected to the non-inversion control terminals and the inversion control terminals of the fifth to seventh analog switches ASW5 to ASW7 via signal lines. At the time of inspection, the inversion selection signal SELX is supplied to the inversion control terminals of the fifth to seventh analog switches ASW5 to ASW7 via the first analog switch ASW1, and the selection signal SEL is supplied to the inversion control terminal via the second analog switch ASW2. It is supplied to the normal rotation control terminals of the fifth to seventh analog switches ASW5 to ASW7. On the other hand, at the time of non-inspection, the third analog switch ASW3 and the fourth analog switch ASW4 (auxiliary switch) are turned on. Therefore, at the time of non-inspection, the inversion control terminals of the fifth to seventh analog switches ASW5 to ASW7 are connected to the power supply line to which the high-potential power supply VDD is supplied, and their non-inversion control terminals are connected to the low-potential power supply VSS. Connected to the supplied power line.
[0032]
As a result, at the time of inspection, the first to third inspection signals TS1 to TS3 are supplied to the data lines 3-1 to 3-3 via the fifth to seventh analog switches ASW5 to ASW7, respectively, and the inspection for disconnection or the like is performed. It is possible to execute. That is, the fifth to seventh analog switches ASW5 to ASW7 function as separation switches for separating and connecting the inspection circuit 300A and the data line 3.
[0033]
According to the inspection circuit 300A in the present embodiment, there are the following advantages. First, the amount of charge leakage between the data line 3 and the inspection circuit 300A during non-inspection can be significantly reduced. At the time of the non-test, the first and second analog switches ASW1 and ASW2 are turned off. Therefore, unless any potential is applied to the signal line, one of the input / output terminals of the fifth to seventh analog switches ASW5 to ASW7 becomes Floating state. Therefore, when the potential fluctuates, such as when noise is superimposed on the signal line, the off-resistance of the fifth to seventh analog switches ASW5 to ASW7 may decrease, and the leakage amount may increase. However, in the present embodiment, the third and fourth analog switches ASW3 and ASW4 connect the potential of the signal line to the high-potential power supply or the low-potential power supply, so that the fifth to seventh analog switches ASW5 to ASW7 are connected. The off state can be ensured, and the leak amount can be reduced.
[0034]
Second, the resistance of the test circuit 300A can be reduced. In the conventional test circuit, two analog switches are connected in series between the test line and the data line, whereas in the present embodiment, the test lines T1 to T3 are connected via one analog switch ASW5 to ASW7. And the data lines 3-1 to 3-3 are connected.
[0035]
Third, the circuit scale can be significantly reduced. Comparing the conventional test circuit shown in FIG. 10 with the test circuit 300A according to the present embodiment shown in FIG. 2, it seems that only the third and fourth analog switches ASW3 and ASW4 have an increased circuit configuration. However, since the analog switch SWA shown in FIG. 10 passes an inspection signal, it is necessary to suppress the on-resistance value of the analog switch SWA. Therefore, the channel width of the TFT constituting the analog switch SWA must be increased. On the other hand, the first to fourth analog switches ASW1 to ASW4 of the present embodiment are merely connected to the control terminals of the fifth to seventh analog switches ASW5 to ASW7. Therefore, the first to fourth analog switches ASW1 to ASW4 need only supply a current for controlling the gate voltages of the fifth to seventh analog switches ASW5 to ASW7, so that the transistor size can be significantly reduced. . As a result, the area occupied by the inspection circuit 300A can be significantly reduced, and the frame area can be reduced to reduce the cost of the liquid crystal panel AA.
[0036]
<1-3: Electrical configuration of liquid crystal panel AA>
FIG. 3 is a perspective view illustrating a configuration of the liquid crystal panel AA, and FIG. 4 is a cross-sectional view taken along line ZZ ′ in FIG. As shown in these figures, the liquid crystal panel AA includes an element substrate 151 such as glass on which the pixel electrodes 6 and the like are formed and a transparent counter substrate 152 such as glass on which the common electrodes 158 and the like are formed. A predetermined gap is maintained by a sealing material 154 in which 153 is mixed, and the electrodes are bonded so that the electrode forming surfaces face each other, and a liquid crystal 155 as an electro-optical material is sealed in the gap. Note that the sealant 154 is formed along the periphery of the opposing substrate 152, but is partially open to seal the liquid crystal 155. Therefore, after the liquid crystal 155 is sealed, the opening is sealed with the sealing material 156.
[0037]
Here, a data line driving circuit 200 is formed on one side of the sealing material 154 opposite to the element substrate 151 to drive the data lines 3 extending in the Y direction. A plurality of connection electrodes 157 are formed on one side to input various signals necessary for controlling the inspection circuit 300A in addition to various signals from a timing generation circuit (not shown). A scanning line driving circuit 100 is formed on one side adjacent to the one side, and is configured to drive the scanning lines 2 extending in the X direction from both sides. Further, an inspection circuit 300A is formed on one side opposite to this one side, so that the inspection of the data line 3 can be executed at the time of inspection.
[0038]
On the other hand, the common electrode 158 of the opposing substrate 152 is electrically connected to the element substrate 151 by a conductive material provided at at least one of four corners in a bonding portion with the element substrate 151. In addition, the opposing substrate 152 is provided with, for example, first, color filters arranged in a stripe shape, a mosaic shape, a triangle shape, or the like according to the use of the liquid crystal panel AA. Thirdly, a black matrix such as resin black in which a metal material such as nickel or nickel, or carbon or titanium is dispersed in a photoresist is provided. Third, a backlight for irradiating the liquid crystal panel AA with light is provided. In particular, in the case of application for color light modulation, a black matrix is provided on the counter substrate 152 without forming a color filter. Further, a light-shielding film for shielding light is formed in a peripheral area of the counter substrate 152, so that a frame as a non-display area is formed.
[0039]
In addition, on the opposing surfaces of the element substrate 151 and the opposing substrate 152, an alignment film or the like rubbed in a predetermined direction is provided, respectively, and on the back side thereof, a polarizing plate (not shown) corresponding to the alignment direction is provided. Are respectively provided. However, when a polymer-dispersed liquid crystal in which fine particles are dispersed in a polymer is used as the liquid crystal 155, the above-described alignment film, polarizing plate, and the like become unnecessary, and the light use efficiency is increased. This is advantageous in reducing power consumption.
[0040]
Note that instead of forming part or all of the peripheral circuits such as the scanning line driving circuit 100, the data line driving circuit 200, and the inspection circuit 300A on the element substrate 151, for example, TAB (Tape Automated Bonding) technology is used. The driving IC chip mounted on the film may be electrically and mechanically connected via an anisotropic conductive film provided at a predetermined position on the element substrate 151. (Chip On Grass) technology may be used to electrically and mechanically connect to a predetermined position of the element substrate 151 via an anisotropic conductive film.
[0041]
<2. Second Embodiment>
The liquid crystal device according to the second embodiment has the same configuration as the liquid crystal device according to the first embodiment except that a test circuit 300B is used instead of the test circuit 300A. FIG. 5 is a block diagram illustrating a configuration of an inspection circuit 300B according to the second embodiment.
[0042]
The test circuit 300B shown in FIG. 5 differs from the test circuit 300A shown in FIG. 2 in that the inversion control signal GCX is supplied to the drain of the TFT forming the third analog switch ASW3 and the fourth analog switch ASW4 is formed. This is the point that the control signal GC is supplied to the source of the TFT to be controlled.
[0043]
Since the control signal GC is at the low level when not selected and the inversion control signal GCX is at the high level, the inversion control terminals of the fifth to seventh analog switches ASW5 to ASW7 are pulled up during non-inspection, and , Their forward control terminals are pulled down.
[0044]
Therefore, it is not necessary to route the power supply lines for supplying the positive power supply VDD and the negative power supply VSS, and the configuration can be simplified, and the area occupied by the inspection circuit 300B can be reduced.
[0045]
<3. Third embodiment>
The liquid crystal device according to the third embodiment performs AC driving by inverting the signal potentials of the image signals R, G, and B at a predetermined cycle around the potential of the common electrode. This liquid crystal device has the same configuration as the liquid crystal device of the second embodiment except that a test circuit 300C is used instead of the test circuit 300B.
[0046]
FIG. 6 is a block diagram showing a configuration of an inspection circuit 300C according to the third embodiment. The test circuit 300C shown in FIG. 6 differs from the test circuit 300B shown in FIG. 5 in that a unit U0 is provided. The unit U0 has a function of fixing the inspection lines T1 to T3 at the time of non-inspection to the common electrode potential VCOM.
[0047]
The unit U0 includes eighth to tenth analog switches ASW8 to ASW10. The common electrode potential VCOM is supplied to one input terminal of each of the eighth to tenth analog switches ASW8 to ASW10 via a potential line. The other input terminals are connected to inspection lines T1 to T3, respectively. The inversion control signal GCX is supplied to the non-inversion control terminals of the eighth to tenth analog switches ASW8 to ASW10, while the control signal GC is supplied to their inversion control terminals. The eighth to tenth analog switches ASW8 to ASW10 are turned off during a test, and turned on during a non-test. Therefore, at the time of non-inspection, the potentials of the inspection lines T1 to T3 are fixed to the common electrode potential VCOM.
[0048]
As described above, since the potentials of the image signals R, G, and B fluctuate around the common electrode potential VCOM, if the potentials of the inspection lines T1 to T3 are fixed to the common electrode potential VCOM during non-inspection, the fifth to seventh potentials are set. It is possible to reduce the potential difference between the source and the drain of the TFT forming the analog switches ASW5 to ASW7. As a result, it is possible to greatly reduce the charge leakage between the data line 3 and the inspection circuit 300.
[0049]
In addition, the composition of an electro-optical material such as a liquid crystal changes when a DC voltage is applied, and so-called burn-in occurs. For this reason, it is usual to drive by AC drive which inverts an applied voltage. The AC driving includes a method of inverting the potential of the common electrode at a predetermined cycle around the reference potential, and a method of fixing the common electrode potential VCOM and inverting the polarity of the image signal at a predetermined cycle around this potential. In any case, the common electrode potential VCOM becomes the center potential. In the above-described embodiment, the common electrode potential VCOM may be inverted at a predetermined cycle around the reference potential. In this case, the potential of the inspection lines T1 to T3 fluctuates at a predetermined cycle during non-inspection. .
[0050]
<4. Application>
<4-1: Configuration of Element Substrate>
In each of the above-described embodiments, the element substrate 151 of the liquid crystal panel AA is formed of a transparent insulating substrate such as glass, a silicon thin film is formed on the substrate, and the source, drain, and channel are formed on the thin film. Although the formed TFT constitutes the elements of the pixel switching element (TFT 50), the scanning line driving circuit 100, the data line driving circuit 200, and the inspection circuits 300A to 300C, the present invention is not limited to this. Not something.
[0051]
For example, the element substrate 151 is formed using a semiconductor substrate, and a switching element of a pixel or an element of various circuits is formed using an insulated gate field effect transistor in which a source, a drain, and a channel are formed on the surface of the semiconductor substrate. Is also good. When the element substrate 151 is formed of a semiconductor substrate as described above, it cannot be used as a transmissive display panel. Therefore, the pixel electrode 6 is formed of aluminum or the like and used as a reflective type. Alternatively, the pixel substrate 6 may simply be of a reflection type while the element substrate 151 is a transparent substrate.
[0052]
Furthermore, in the above-described embodiment, the switching element of the pixel has been described as a three-terminal element represented by a TFT, but may be configured with a two-terminal element such as a diode. However, when a two-terminal element is used as a pixel switching element, the scanning line 2 is formed on one substrate, the data line 3 is formed on the other substrate, and the two-terminal element is connected to the scanning line 2 or the data line. 3 and the pixel electrode. In this case, the pixel is composed of a liquid crystal and a two-terminal element connected in series between the scanning line 2 and the data line 3.
[0053]
Further, the present invention has been described as an active matrix type liquid crystal display device. However, the present invention is not limited to this, and is also applicable to a passive type using STN (Super Twisted Nematic) liquid crystal. Further, as the electro-optical material, in addition to the liquid crystal, the present invention can be applied to a display device that uses an electroluminescence element or the like to perform display by the electro-optical effect. That is, the present invention is applicable to all electro-optical devices having a configuration similar to the above-described liquid crystal device.
[0054]
<4-2: Electronic device>
Next, a case where the above-described liquid crystal device is applied to various electronic devices will be described.
<4-2-1: Projector>
First, a projector using the liquid crystal device as a light valve will be described. FIG. 7 is a plan view showing a configuration example of the projector. As shown in this figure, inside the projector 1100, a lamp unit 1102 including a white light source such as a halogen lamp is provided. The projection light emitted from the lamp unit 1102 is separated into three primary colors of RGB by four mirrors 1106 and two dichroic mirrors 1108 arranged in a light guide 1104, and is used as a light valve corresponding to each primary color. The light enters the liquid crystal panels 1110R, 1110B, and 1110G.
[0055]
The configurations of the liquid crystal panels 1110R, 1110B, and 1110G are the same as those of the above-described liquid crystal panel AA, and are driven by R, G, and B primary color signals supplied from an image signal processing circuit (not shown). Then, the light modulated by these liquid crystal panels AA enters the dichroic prism 1112 from three directions. In the dichroic prism 1112, the R and B lights are refracted at 90 degrees, while the G light travels straight. Accordingly, as a result of combining the images of the respective colors, a color image is projected on a screen or the like via the projection lens 1114.
[0056]
Here, focusing on the display images by the liquid crystal panels 1110R, 1110B, and 1110G, the display images by the liquid crystal panels 1110G need to be horizontally inverted with respect to the display images by the liquid crystal panels 1110R, 1110B.
[0057]
Since light corresponding to the primary colors of R, G, and B is incident on the liquid crystal panels 1110R, 1110B, and 1110G by the dichroic mirror 1108, it is not necessary to provide a color filter.
[0058]
<4-2-2: Mobile computer>
Next, an example in which the liquid crystal panel AA is applied to a mobile personal computer will be described. FIG. 8 is a perspective view showing the configuration of the personal computer. In the figure, a computer 1200 includes a main body 1204 having a keyboard 1202, and a liquid crystal display unit 1206. The liquid crystal display unit 1206 is configured by adding a backlight to the back of the liquid crystal panel 1005 described above.
[0059]
<4-2-3: Mobile phone>
Further, an example in which the liquid crystal panel AA is applied to a mobile phone will be described. FIG. 9 is a perspective view showing the configuration of the mobile phone. In the figure, a mobile phone 1300A includes a plurality of operation buttons 1302 and a reflective liquid crystal panel 1005. In this reflection type liquid crystal panel 1005, a front light is provided on the front surface as needed.
[0060]
In addition to the electronic devices described with reference to FIGS. 7 to 9, a liquid crystal television, a viewfinder type, a video tape recorder of a monitor direct-view type, a car navigation device, a pager, an electronic notebook, a calculator, a word processor, a work Stations, videophones, POS terminals, devices equipped with touch panels, and the like. Needless to say, the present invention can be applied to these various electronic devices.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating an overall configuration of a liquid crystal device according to a first embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of an inspection circuit 300A used in the apparatus.
FIG. 3 is a perspective view showing an appearance of a liquid crystal panel AA used in the device.
FIG. 4 is a partial cross-sectional view illustrating a structure of a liquid crystal panel AA.
FIG. 5 is a block diagram illustrating a configuration of an inspection circuit 300A used in a liquid crystal device according to a second embodiment of the present invention.
FIG. 6 is a block diagram illustrating a configuration of an inspection circuit 300B used in a liquid crystal device according to a third embodiment of the present invention.
FIG. 7 is a cross-sectional view of a video projector as an example of an electronic apparatus to which the liquid crystal panel AA is applied.
FIG. 8 is a perspective view illustrating a configuration of a personal computer as an example of an electronic apparatus to which the liquid crystal panel AA is applied.
FIG. 9 is a perspective view illustrating a configuration of a mobile phone as an example of an electronic apparatus to which the liquid crystal panel AA is applied.
FIG. 10 is a block diagram of an element substrate provided with a conventional inspection circuit.
[Explanation of symbols]
AA: Liquid crystal panel
2 ... scanning line
3: Data line
6 ... pixel electrode
300… Inspection circuit
50 ... TFT (switching element)
100 ... scanning line drive circuit
200 data line drive circuit
300… Inspection circuit
ASW1 to ASW10 ... first to tenth analog switches

Claims (10)

A plurality of scanning lines, a plurality of data lines, an inspection circuit used in an electro-optical panel including switching elements arranged in a matrix corresponding to the intersection of the scanning lines and the data lines,
An inspection line for supplying an inspection signal;
A separation switch connected between the scanning line or the data line and the inspection line,
A selection switch in which a selection signal is supplied to one input / output terminal and the other input / output terminal is connected to a control terminal of the separation switch via a signal line;
A control line connected to a control terminal of the selection switch, for supplying a control signal for turning on the selection switch during inspection and turning off the selection switch during non-inspection;
An inspection circuit, comprising: an auxiliary switch that is connected between a wiring to which a potential for turning off the separation switch is supplied and the signal line, and that is turned on / off exclusively with the selection switch. The inspection circuit according to claim 1, wherein the wiring is a power supply line for supplying power. The inspection circuit according to claim 1, wherein the wiring is the control line. 4. A test line switch connected between a potential line to which a predetermined potential is supplied and the test line and turned off during a test and turned on during a non-test. 2. The inspection circuit according to claim 1. The inspection circuit according to claim 4, wherein a control terminal of the inspection line switch is connected to the control line. A plurality of scanning lines, a plurality of data lines, an inspection circuit used in an electro-optical panel including switching elements arranged in a matrix corresponding to the intersection of the scanning lines and the data lines,
An inspection line for supplying an inspection signal;
A separation switch connected between the scanning line or the data line and the inspection line, turned on during inspection, and turned off during non-inspection;
An inspection circuit, comprising: an inspection line switch connected between a potential line to which a predetermined potential is supplied and the inspection line and turned off during an inspection and turned on during a non-inspection. An element substrate on which the plurality of scanning lines, the plurality of data lines, and the switching elements are formed, a counter substrate having a common electrode, and an electro-optical material interposed between the element substrate and the counter substrate. An inspection circuit used for an electro-optical panel,
The inspection circuit according to claim 4, wherein the predetermined potential is a potential of the common electrode. The inspection circuit according to claim 7, wherein the potential of the common electrode is inverted at a predetermined cycle around a reference potential. An electro-optical panel comprising the inspection circuit according to any one of claims 1 to 8. An electronic apparatus comprising the electro-optical panel according to claim 9.

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