JP4239299B2 - Active matrix type liquid crystal display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device used for a notebook PC, a portable terminal, and the like, and in particular, an array inspection circuit for an active matrix liquid crystal display device in which peripheral circuits such as a drive circuit are integrally formed on the same array substrate as a pixel portion. It is about.
[0002]
[Prior art]
As a direct-view type liquid crystal display device, a thin film transistor (hereinafter referred to as TFT) made of amorphous Si (a-Si) or polycrystalline Si (p-Si) is provided for each pixel, and a voltage is applied to the pixel electrode by this switching operation to provide liquid crystal. Driven active matrix type liquid crystal display devices have come to be used in many respects because of high image quality.
[0003]
In the a-Si TFT type liquid crystal display device, the driving circuit for driving the pixels is externally attached to the driving LSI. However, in recent years, not only the pixel portion of the panel but also the peripheral circuits such as the driving circuit with high performance p-Si TFTs. A p-Si TFT type liquid crystal display device integrally formed on the same array substrate has been developed. By incorporating the drive circuit, not only can the number of external connections be significantly reduced, but an external drive LSI is not required, and therefore material costs can be reduced.
[0004]
As a configuration of the driving circuit, there are a dot sequential method and a line sequential method. FIG. 10 shows a circuit configuration of a liquid crystal display device having an analog dot sequential driving circuit. 1 is a gate line, 2 is a data line, 3 is a TFT switch for pixels (hereinafter also referred to as a pixel TFT), 4 is a pixel electrode, 5 is a storage capacitor, 6 is a signal input line, 7 is a signal terminal, and 8 is vertical. A driving circuit 100 is an analog dot sequential horizontal driving circuit. The drive circuit 100 has a simple configuration of a shift element 20 and a switching element 21 composed of TFTs. An input signal that is serially input from the signal terminal 7 to the signal input line 6 is sequentially turned on by the scanning circuit of the shift register 20 and applied to the data line 2 as it is, and is sequentially written for each pixel. This dot-sequential method is currently in practical use. For example, Japanese Patent Laid-Open No. 10-96754 also shows a circuit configuration of a dot sequential type liquid crystal panel.
[0005]
On the other hand, the line sequential method includes an analog method and a digital method. FIG. 11 shows a circuit configuration of a liquid crystal display device having an analog line sequential driving circuit. The analog line sequential driving circuit 101 includes a shift register 30, a sample hold 31, and an amplifier 32. In the analog system, an analog input signal is held by a sample hold 31 for one line, amplified by an amplifier 32, and a signal voltage is supplied to all data lines 2 all at once in synchronization with the output of the vertical drive circuit 8 to drive vertically. Write to all the pixels on the gate selected by the circuit 8.
[0006]
FIG. 12 shows a circuit configuration of a liquid crystal display device having a digital line sequential type horizontal drive circuit. The digital line sequential horizontal driving circuit 102 includes a shift register 40, a latch 41, and a D / A converter 42. The D / A converter 42 includes resistance division, capacitance division, PWM method, and the like. In the digital method, the digital input signal of the signal input line 6 is latched for one line, converted into a voltage corresponding to the gradation by the D / A converter 42, and the signal voltage is supplied to the data line 2 all at once. In the D / A converter 42 in the figure, a reference voltage corresponding to a gradation is supplied to the reference voltage line 43 by a resistance division method or the like, and the reference voltage line 43 corresponding to the gradation is connected to a plurality of switches 44. This is the method to select with. In the figure, for the sake of simplicity, an example of parallel input with a gradation of 2 bits is shown. This method has the advantage of less output variation than amplification by an analog amplifier, but has the disadvantage that the circuit area becomes very large as the number of gradations increases.
[0007]
The array substrate is subjected to array inspection after completion of the substrate. Since the array substrate is bonded to the color filter substrate and a panel assembly process such as liquid crystal injection is performed later, it is necessary to find a defective panel at an early stage for cost reduction. In particular, since the number of TFTs further increases when a drive circuit is built in, array inspection becomes more important.
[0008]
For example, FPD inspection technology is introduced in P84-89 of Monthly FPD Intelligence 19988.9 of Press Journal. The array inspection mainly includes an optical inspection method and an electrical inspection method. The optical inspection method is mainly an appearance inspection such as a pattern defect, and a TFT defect having no appearance abnormality cannot be detected. The electrical inspection method includes an open / short test method, a pixel charge measurement method, a TEG inspection, and the like. Since the TEG inspection is performed by a dedicated inspection circuit provided around the panel, the quality of the panel itself can be determined only by analogy.
[0009]
The pixel charge measurement method is superior to the open / short test method in that it can detect not only the open / short of the gate line and the data line but also the quality of the pixel. This applies probes to all gate lines and data lines, applies an ON signal to the gate lines to turn on the pixel TFTs, and writes a constant voltage applied to the data lines to the storage capacitor of the pixels. After holding for a certain time, an ON signal is applied to the gate line again to turn on the pixel TFT, and the charge stored in the storage capacitor is read out by an external detector (integrator). Not only the wiring but also the quality of the pixel can be determined by the magnitude of the output of the detector.
[0010]
[Problems to be solved by the invention]
However, an array inspection method for a liquid crystal display device in which a drive circuit is integrally formed has not been established at present, and there are few documents introducing this inspection technique.
For example, the above-described Japanese Patent Laid-Open No. 10-96754 proposes a dot sequential type horizontal driving circuit inspection method. FIG. 13 shows an inspection circuit configuration of a liquid crystal display device having a dot sequential driving circuit. This is in principle a pixel charge measurement method. At the time of writing at the time of inspection, the switch 11 is on the W (Write) side, and an input signal having a constant voltage is input from the input terminal 7 to the input signal line 6. In the shift register 50 of the horizontal driving circuit 103, the switching elements 51 made of TFTs are sequentially turned on and input signals are given to the data lines 2, and the vertical driving circuit sequentially applies on signals to the gate lines 1 to turn on the pixel TFTs 3. The data is written in the storage capacitor 5 and held for a certain time. At the time of inspection reading, the switch 11 is on the R (Read) side, the ON signal is again applied to the gate line 1 to turn on the pixel TFT 3, and the charge stored in the storage capacitor 5 is sequentially switched by the shift register 50. 51 is turned on, and electric charges are read from the data line 2 through the signal input line 6 by an external detector (integrator) 10. In the dot sequential method, pixel charges can be detected because only the switching elements are connected between the data lines and the input signal lines at the time of reading. That is, the dot sequential driving circuit also functions as a pixel signal readout circuit. Further, in this example, since the readout terminal also serves as the input terminal, there is an advantage that the number of probes necessary for the inspection is small.
[0011]
However, there has been no report on an inspection method using a more complicated line sequential driving circuit. In the line-sequential method, the output line and the input signal line have amplifiers and D / A converters in the drive circuit, so the paths are separated, and the internal circuit is various, so that it is difficult to detect pixel charges.
An object of the present invention is to provide a configuration of a pixel signal readout circuit capable of determining the quality of each pixel in an active matrix liquid crystal display device in which a drive circuit is integrally formed on the same substrate, in particular, with a line-sequential drive circuit, and this An object of the present invention is to provide a liquid crystal display device having a reading circuit.
[0012]
[Means for Solving the Problems]
First active matrix type according to the present inventionliquid crystalThe display device includes a line sequential horizontal drive circuit, a vertical drive circuit, a TFT array including a TFT switch, a pixel electrode, and a storage capacitor in each pixel portion, and a signal from a shift register of the line sequential horizontal drive circuit. The pixel signal readout circuit for sequentially selecting the horizontal pixel columns is integrally formed on the same array substrate.
[0016]
Also,The pixel signal readout circuit has a plurality of bypass lines in the line-sequential horizontal driving circuit for connecting an input signal line to the line-sequential horizontal driving circuit and a plurality of data lines through switching transistors. ,Sequentially selected by the shift register of the horizontal driving circuit and the switching transistorStored in the storage capacitor via the data line and the bypass lineThe pixel signals are sequentially output to the outside via the bypass line.
[0017]
Also,From the data line to the line sequential horizontal drive circuitReference voltage supply for D / A converterlinePart ofOutput the pixel signal held in the storage capacitor to the outside viaIs.
[0018]
The horizontal drive circuit is connected to the data line of the TFT array via a switching element,When outputting the pixel signal held in the storage capacitor to the outside,Switching element is selectively turned offThus, the output side of the line sequential type horizontal drive circuit is set to high impedance.Is.
[0019]
The drive frequency of the pixel signal readout circuit isLine sequential methodHorizontal drive circuitWrite driveControl independent of frequencyRumoIt is.
[0020]
The pixel signal readout circuitPixel signal from the outsideRead-out and supply of image signals from the outside to the line-sequential horizontal drive circuit via a common terminalSwitchableIt is comprised so that it may be performed.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a circuit diagram of a liquid crystal display device according to the present invention. In the figure, 104 is a line sequential horizontal drive circuit, 8 is a vertical drive circuit, 108 is a TFT array, 9 is an array substrate, 200 is a pixel signal readout circuit, and the pixel signal readout circuit 200 is connected to the TFT array 108. Since the data line is connected to one end of the data line and the other end of the data line is connected to the 104 horizontal drive circuit, the pixel signal readout circuit is located at the end of the array substrate 9. The pixel signal readout circuit 200 includes a shift register 201 and a plurality of switching transistors 202 including TFTs. Reference numeral 203 denotes a readout line at the time of inspection. At the time of test writing, the switches 11 and 12 are on the W side, an on signal is applied to the gate line 1 to turn on the pixel TFT 3, and a constant signal voltage is passed through the signal line 2 by the horizontal drive circuit 104. It is written in the storage capacitor 5 and held for a certain time. At the time of inspection readout, the switches 11 and 12 are on the R side, and an on signal is again applied to the gate line 1 to turn on the pixel TFT 3, and the charge stored in the storage capacitor 5 is transferred to the shift register of the pixel signal readout circuit 200. The switching transistor 202 is sequentially turned on in 201, and is read out by the external detector 10 via the readout line 203 and the signal terminal 7.
[0022]
In this embodiment, since the pixel signal readout circuit is arranged at the end of the array substrate 9 as described above, the pixel signal readout circuit can be cut and removed after the inspection. By removing the pixel signal readout circuit, the panel size can be reduced, which is advantageous for mounting on a personal computer or the like.
In this embodiment, the signal terminal 7 is also used as a test readout terminal. In this case, there is an advantage that the wiring layout is easy. However, as shown in FIG. 2, a readout terminal may be provided separately, and the effect of enabling evaluation for each pixel is the same.
[0023]
Embodiment 2. FIG.
FIG. 3 is a circuit diagram of the liquid crystal display device according to the present invention. In the figure, 105 is a line-sequential horizontal drive circuit, 60 is a shift register, 61 is another circuit, and 300 is a pixel signal readout circuit provided between the drive circuit and the screen. The pixel signal readout circuit 300 includes a switch 301 connected to the output of the shift register 60 and a switching transistor 302 that can be interlocked with the output of the shift register. The pixel signal readout circuit 300 has a function of sequentially selecting the data lines 2 and is driven in a dot sequential manner. This corresponds to the circuit configuration. Reference numeral 303 denotes a readout line at the time of inspection. The above circuit is configured on the array substrate 9. At the time of test writing, the switches 11 and 12 are turned to the W side, the switch 301 is turned off, an on signal is applied to the gate line 1 to turn on the pixel TFT 3, and a constant signal voltage is output from the output of the horizontal drive circuit 105. Is written in the storage capacitor 5 of the pixel and held for a certain period of time. At the time of inspection readout, the switch is turned to the R side, the switch 301 is turned on, an on signal is again applied to the gate line 1 to turn on the pixel TFT 3, and the charge stored in the storage capacitor 5 is shifted by the drive circuit 105. The switching transistors 302 are sequentially turned on in conjunction with the output of the register 60 and read by the external detector 10 via the read line 303 and the signal terminal 7. Since the circuit at the time of reading of the inspection is a circuit configuration corresponding to a dot sequential driving circuit, the inspection can be performed. Not only the drive circuit and the wiring but also the quality of the pixel can be determined by the magnitude of the output of the detector 10.
[0024]
In this embodiment, the length of the readout signal line up to the switch can be made shorter than that in the first embodiment, and the influence of signal wiring resistance and wiring capacitance can be reduced.
In this embodiment, the shift register included in the pixel signal readout circuit is also used as the shift register included in the horizontal drive circuit, so that the circuit configuration is simplified and the manufacturing yield can be improved.
In this embodiment, a part of the signal terminal 7 is also used as an inspection readout terminal, but a readout terminal may be provided separately.
[0025]
Embodiment 3 FIG.
FIG. 4 is a circuit diagram of the liquid crystal display device according to the present invention. In the figure, 105 is a line-sequential horizontal drive circuit, 60 and 62 are shift registers, 61 is another circuit, and 300 is a pixel signal readout circuit provided between the drive circuit and the TFT array. The pixel signal readout circuit 300 includes a shift register 62 and a switching transistor 302 that switches according to the output of the shift register 62. The pixel signal readout circuit 300 has a function of sequentially selecting the data lines 2, and corresponds to a dot sequential driving circuit configuration. Reference numeral 303 denotes a readout line at the time of inspection. The above circuit is configured on the array substrate 9. During the test writing, the switches 11 and 12 are turned to the W side, the switching transistor 302 is turned off, an on signal is applied to the gate line 1 to turn on the pixel TFT 3, and a constant signal is output from the output of the horizontal drive circuit 105. The voltage is written in the storage capacitor 5 of the pixel and held for a certain time. At the time of reading of the inspection, the switch is on the R side, the ON signal is applied again to the gate line 1 to turn on the pixel TFT 3, and the charge stored in the storage capacitor 5 is output from the shift register 62 of the pixel signal reading circuit 300. The switching transistors 302 are sequentially turned on in conjunction with the signal lines and read by the external detector 10 via the read line 303 and the signal terminal 7. Since the circuit at the time of reading of the inspection is a circuit configuration corresponding to a dot sequential driving circuit, the inspection can be performed. Not only the drive circuit and the wiring but also the quality of the pixel can be determined by the magnitude of the output of the detector 10.
[0026]
In this embodiment, the length of the read signal line up to the switching device can be made shorter than that of the first embodiment as in the second embodiment, and the influence of signal wiring resistance and wiring capacitance can be reduced.
In this embodiment, since the shift register included in the pixel signal readout circuit can be driven independently of the shift register included in the horizontal drive circuit, detailed inspection can be performed by changing the drive frequency.
In this embodiment, a part of the signal terminal 7 is also used as an inspection readout terminal, but a readout terminal may be provided separately.
[0027]
Embodiment 4 FIG.
FIG. 5 is a circuit diagram of another liquid crystal display device according to the present invention. In the figure, 106 is an analog line sequential horizontal drive circuit, 70 is a shift register, 71 is a switching element, 72 is a sample and hold circuit, 73 is an amplifier, and 74 is a bypass line connecting the input side and the output side. When the test is written, the switches 11, 75 and 76 are on the W side. An on signal is applied to the gate line 1 to turn on the pixel TFT 3, and a constant signal voltage is written into the storage capacitor 5 of the pixel by the horizontal driving circuit 106 and held for a certain period of time. At the time of inspection reading, the switches 11, 75, and 76 are on the R side, the ON signal is again applied to the gate line 1 to turn on the pixel TFT 3, and the charges stored in the storage capacitor 5 are sequentially transferred by the shift register 70. The switching element 71 is turned on, the data line 2 is returned to the read line 77 via the bypass line 74, and read by the external detector 10 via the signal terminal 7. The signal charge does not pass through the amplifier 73 and the sample hold circuit 72 in the driving circuit, and the circuit at the time of reading of the inspection corresponds to a dot sequential time driving circuit, so that the inspection can be performed.
In this embodiment, the signal terminal 7 is provided with a switch 76 and serves as an inspection readout terminal. However, an inspection readout terminal may be provided separately.
[0028]
Embodiment 5 FIG.
FIG. 6 is a circuit diagram of another liquid crystal display device according to the present invention. In the figure, 107 is a digital line sequential horizontal drive circuit, 80 is a shift register, 81 is a switching transistor, 82 is a latch, 83 is a D / A converter, 84 is a bypass line connecting the input side and the output side, 85 is A switch 86 is a readout line. The horizontal drive circuit 107 has a circuit configuration on the output side that can be brought into a high impedance state by the switch 85 or the like when reading the inspection. The D / A converter 83 in the figure is configured such that a reference voltage corresponding to the gradation is supplied to the reference voltage line 43 by a resistance division method or the like, and the reference voltage line 43 corresponding to the gradation is connected to a plurality of switches 85. This is the method to select with. In the figure, for the sake of simplicity, an example of parallel input with a gradation of 2 bits is shown. At the time of inspection writing, the switches 11 and 87 are on the W side, and a bit signal having a gradation determined by the inspection specifications is input to the signal input line 6. The grayscale signal becomes a predetermined voltage signal by the horizontal drive circuit 107 and is written in the storage capacitor 5 of the pixel, and is held for a certain time. When the inspection is read out, the switches 11 and 87 are on the R side, the ON signal is again applied to the gate line 1 to turn on the pixel TFT 3, and the charge stored in the storage capacitor 5 is sequentially switched by the shift register 80. The transistor 81 is turned on, the data line 2 is returned to the read line 86 via the bypass line 84 and the switching transistor 81, and read by the external detector 10 via the input terminal. Since the charge does not pass through the D / A converter and latch in the drive path, and the circuit at the time of reading of the inspection corresponds to a dot sequential driving circuit, inspection for each pixel becomes possible.
In this embodiment, a part of the signal terminal 7 is also used as an inspection readout terminal, but a readout terminal may be provided separately.
[0029]
Embodiment 6 FIG.
FIG. 7 is a circuit diagram of another liquid crystal display device according to the present invention. In the figure, 107 is a digital line sequential horizontal drive circuit, 90 is a shift register, 11 and 91 are switches, 95 and 97 are switches, 92 is a latch, 93 is a D / A converter, and 94 is a plurality of reference voltage lines. 96 are readout lines for connecting a part of the signal input line 6 and the reference voltage line 94. A D / A converter 93 in the figure is configured to be supplied with a reference voltage corresponding to a gradation from a reference voltage line 94 by a resistance division method or the like, and the reference voltage line 94 is selected by a plurality of switches 95. It is a method. In the figure, for the sake of simplicity, an example of parallel input with a gradation of 2 bits is shown.
When writing the test, the switches 11 and 91 are turned to the W side, the switch 97 is turned off, and a digital signal having a predetermined gradation is inputted to the signal input line 6. The gradation signal becomes a predetermined signal voltage by the output of the horizontal drive circuit 107 and is written in the storage capacitor 5 of the pixel, and is held for a certain time. At the time of inspection readout, the switches 11 and 91 are turned to the R side, the switch 97 is turned on, an on signal is again applied to the gate line 1 to turn on the pixel TFT 3, and the charge stored in the storage capacitor 5 is The specific switch of the switch 95 is sequentially turned on in conjunction with the output of the shift register 90, and flows from the data line 2 to the read line 96 via a part of the reference voltage line 94. Then, the signal is read by the external detector 10 via the signal terminal 7. Since the charge does not pass through a part of the D / A converter in the horizontal drive circuit and the latch, and the circuit at the time of test readout corresponds to the drive circuit of the dot sequential method, the test for each pixel becomes possible.
In this embodiment, a part of the signal terminal 7 is also used as an inspection readout terminal, but a readout terminal may be provided separately.
[0030]
Embodiment 7 FIG.
FIG. 8 is a circuit diagram of the liquid crystal display device according to the present invention. In the figure, reference numeral 104 denotes a line-sequential horizontal drive circuit, 8 denotes a vertical drive circuit, 108 denotes a TFT array, 9 denotes an array substrate, and 200 denotes a pixel signal readout circuit. The TFT array 108 is opposite to the horizontal drive circuit 104. Is provided. The pixel signal readout circuit 200 includes a shift register 201 and a plurality of switching transistors 202. Reference numeral 203 denotes a readout line at the time of inspection. Further, the horizontal driving circuit 104 has a circuit configuration that can turn off the switching element 204 in conjunction with the switching signal and set the output impedance to a high impedance state at the time of reading the inspection. At the time of test writing, the switches 11 and 12 are on the W side, an ON signal is applied to the gate line 1 to turn on the pixel TFT 3, and a constant signal voltage is written to the storage capacitor 5 of the pixel by the horizontal drive circuit 104. It is held for a certain time. When the inspection is read out, the switches 11 and 12 are on the R side, the ON signal is again applied to the gate line 1 to turn on the pixel TFT 3, and the charge stored in the storage capacitor 5 is transferred to the shift register of the pixel signal reading circuit 200. The switching transistor 202 is sequentially turned on in 201, and is read out by the external detector 10 via the readout line 203 and the signal terminal 7. At the time of reading, the switching transistor 204 is in an off state, so that the output side of the horizontal driving circuit 104 is in a high impedance state, and most of the charge stored in the storage capacitor 5 flows to the pixel signal reading circuit 200 side. Since the circuit at the time of inspection reading selects each signal line 1 in order, each pixel can be inspected. Depending on the magnitude of the output of the detector 10, not only the drive circuit and wiring, but also the quality of the pixel can be determined.
In this embodiment, the signal terminal 7 is also used as an inspection readout terminal, but a readout terminal may be provided separately.
[0031]
Embodiment 8 FIG.
FIG. 9 shows another embodiment according to the present invention. In the figure, reference numerals 104A and 104B denote line-sequential horizontal drive circuits, which correspond to two separate display pixel arrays, and input signals A and B corresponding to the respective display pixels are inputted. . The shift register constituting the pixel signal readout circuit 200 is provided with a clock signal input terminal 205 for independently controlling the clock frequency. In general, the performance of a p-Si (polysilicon) transistor or the like used to constitute a drive circuit is lower than that of single crystal Si, and the maximum operable frequency is low. Since the drive frequency increases when the number of pixels is large, for example, as shown in FIG. 9, the drive circuit may be divided into a plurality of parts, and the input signal may be divided into a plurality of parts to reduce the drive frequency. Many. However, the read drive frequency of the inspection circuit does not necessarily need to match the write drive frequency of the drive circuit. If the drive frequency of the inspection circuit can be controlled independently of the frequency of the drive circuit, for example, the frequency will be slower than usual to increase the charge retention time and the integration time of the detector, and the charge retention characteristics of the pixel will be evaluated in detail. It becomes possible to do. If the frequency is low, the pixel readout circuit does not necessarily need to be divided as shown in the figure.
[0032]
Embodiment 9 FIG.
FIG. 2 is a diagram in which the readout terminal and the signal terminal are separately provided in the first embodiment according to the present invention.
[0033]
【The invention's effect】
  As described above, according to the present invention,,eachTFT switch and pixel electrode in the pixel areaAnd storage capacityTFT array with, DroopingDirect drive circuit and,lineA sequential horizontal drive circuit;The data line is sequentially selected by a signal from the shift register of the line sequential horizontal driving circuit, and the pixel signal held in the pixel storage capacitor is output to the outside.Since the pixel signal readout circuit is integrally formed on the same array substrate, it is possible to perform an array inspection in which it is possible to judge the quality of each pixel, which has been impossible in the past, and the cost reduction effect by early detection of defective substrates There is.In addition, the influence of the signal wiring resistance and the wiring capacitance at the time of signal readout can be reduced as compared with the case where the pixel signal readout circuit is provided at the substrate end.
[0037]
  Also,The pixel signal readout circuit has a plurality of bypass lines in the line-sequential horizontal driving circuit for connecting an input signal line to the line-sequential horizontal driving circuit and a plurality of data lines through switching transistors. The pixel signal held in the storage capacitor is sequentially output to the outside through the data line and the bypass line selected by turning on the switching transistor by the shift register of the line sequential horizontal driving circuit.Therefore, the shift register included in the pixel signal readout circuit isLine sequential methodThe shift register included in the horizontal drive circuit can also be used, which simplifies the circuit configuration and improves the manufacturing yield.
[0038]
  Also,From the data line to the line sequential horizontal drive circuitSupply of reference voltage for the D / A converterlinePart ofOutput the pixel signal held in the storage capacitor to the outside viaSoPixelThe area occupied by the signal readout circuit can be reduced, and the panel size can be reduced.
[0039]
  Also, the line sequential horizontal drive circuitThe output side is connected to a plurality of data lines via switching elements, and when the pixel signal held in the storage capacitor is output to the outside,Switching element is selectively turned offThus, the output side of the line sequential type horizontal drive circuit is set to high impedance.Therefore, leakage of signals to the drive circuit during inspection is suppressed, and the charge accumulated for each pixel can be accurately evaluated.
[0040]
  The drive frequency of the pixel signal readout circuit isLine sequential methodHorizontal drive circuitWrite driveControl independent of frequencyRuThus, detailed evaluation of the pixels can be performed by changing the driving frequency.
[0041]
Further, since the readout terminal at the time of inspection of the pixel signal readout circuit also serves as the input terminal at the time of signal writing, the number of terminals can be reduced, and the wiring layout on the substrate becomes easier.
[Brief description of the drawings]
1 is a circuit configuration diagram showing a liquid crystal display device according to Embodiment 1 of the present invention;
FIG. 2 is a circuit configuration diagram showing a liquid crystal display device according to a ninth embodiment of the present invention.
FIG. 3 is a circuit configuration diagram showing a liquid crystal display device according to a second embodiment of the present invention.
FIG. 4 is a circuit configuration diagram showing a liquid crystal display device according to a third embodiment of the present invention.
FIG. 5 is a circuit configuration diagram showing a liquid crystal display device according to a fourth embodiment of the present invention.
FIG. 6 is a circuit configuration diagram showing a liquid crystal display device according to a fifth embodiment of the present invention.
FIG. 7 is a circuit configuration diagram showing a liquid crystal display device according to a sixth embodiment of the present invention.
FIG. 8 is a circuit configuration diagram showing a liquid crystal display device according to a seventh embodiment of the present invention.
FIG. 9 is a circuit configuration diagram showing a liquid crystal display device according to an eighth embodiment of the present invention.
FIG. 10 is a circuit configuration diagram showing a dot sequential drive type liquid crystal display device;
FIG. 11 is a circuit configuration diagram showing a liquid crystal display device of an analog line sequential drive method.
FIG. 12 is a circuit configuration diagram showing a digital line sequential drive type liquid crystal display device.
FIG. 13 is a configuration diagram showing an inspection circuit of an analog dot sequential drive type liquid crystal display device.
[Explanation of symbols]
1 Gate line
2 data lines
3 TFT switch (pixel TFT)
4 Pixel electrode
5 storage capacity
6 Signal input line
7 Signal terminal
8 Vertical drive circuit
9 Array substrate
10 Detector
11 switcher
12 selector
100 Analog dot sequential horizontal drive circuit
101 Analog line sequential horizontal drive circuit
102 Digital line sequential horizontal drive circuit
103 Analog dot sequential horizontal drive circuit
104, 105 line sequential horizontal drive circuit
106 Analog line sequential horizontal drive circuit
107 Digital line sequential horizontal drive circuit
108 TFT array
200 pixel signal readout circuit
201 Shift register
202 Switching transistor
203 Read line
204 Switching transistor
205 Clock signal input terminal
300 Pixel signal readout circuit
301 switch
302 switching transistor
303 Read line

Claims (5)

A pixel including a plurality of data lines and a plurality of scanning signal lines intersecting in an XY matrix, each of which includes a pixel electrode connected via a switching TFT, and a storage capacitor is provided. A TFT array;
A vertical driving circuit having a function of sequentially selecting the scanning signal lines;
A shift register and a holding circuit for holding a pixel signal, each of the pixel signals corresponding to the plurality of data lines is held in the holding circuit by each output signal from the shift register, and the vertical drive circuit A line-sequential horizontal drive circuit that supplies the pixel signals to the corresponding pixels all at once via the plurality of data lines in synchronization with the selection of a scanning signal line;
A pixel signal having a readout line for sequentially selecting the data line by each output signal from the shift register of the line sequential horizontal driving circuit and outputting the pixel signal held in the storage capacitor of the pixel to the outside A readout circuit;
In an active matrix type liquid crystal display device provided on the same substrate ,
The pixel signal readout circuit is provided on the same side as the line sequential horizontal driving circuit with respect to the TFT array,
The readout line is connected to the plurality of data lines via each of a plurality of switching elements controlled by each output signal from the shift register of the line sequential type horizontal drive circuit,
Each output signal from the shift register sequentially turns on the switching element, so that the pixel signal held in the storage capacitor of the selected pixel is transferred from the data line via the switching element. An active matrix type liquid crystal display device which outputs to a readout line . A pixel including a plurality of data lines and a plurality of scanning signal lines intersecting in an XY matrix, and a pixel electrode connected to each intersection via a switching TFT and a storage capacitor is provided. A TFT array;
A vertical driving circuit having a function of sequentially selecting the scanning signal lines;
A shift register and a holding circuit for holding a pixel signal, each pixel signal corresponding to the plurality of data lines is held in the holding circuit by each output signal from the shift register, and the vertical drive circuit A line-sequential horizontal drive circuit that supplies the pixel signals to corresponding pixels all at once via the plurality of data lines in synchronization with selection of a scanning signal line;
A pixel signal having a readout line for sequentially selecting the data line by each output signal from the shift register of the line sequential horizontal driving circuit and outputting the pixel signal held in the storage capacitor of the pixel to the outside A readout circuit;
In an active matrix type liquid crystal display device provided on the same substrate,
The pixel signal readout circuit is provided on the same side of the TFT array as the line sequential horizontal driving circuit,
A plurality of bypass lines connecting the read line and each of the plurality of data lines via each of a plurality of switching transistors controlled by each output signal from the shift register of the line sequential type horizontal drive circuit. In the line sequential horizontal drive circuit,
Each output signal from the shift register sequentially turns on the switching transistor, whereby the pixel signal held in the storage capacitor of the selected pixel is passed from the data line via the bypass line, and An active matrix liquid crystal display device that outputs to the readout line via a switching transistor. A pixel including a plurality of data lines and a plurality of scanning signal lines intersecting in an XY matrix, and a pixel electrode connected to each intersection via a switching TFT and a storage capacitor is provided. A TFT array;
A vertical driving circuit having a function of sequentially selecting the scanning signal lines;
A shift register and a holding circuit for holding a pixel signal, each pixel signal corresponding to the plurality of data lines is held in the holding circuit by each output signal from the shift register, and the vertical drive circuit Synchronously with the selection of the scanning signal line, via the plurality of data lines A line-sequential horizontal drive circuit that supplies the pixel signals to corresponding pixels all at once;
A pixel signal having a readout line for sequentially selecting the data line by each output signal from the shift register of the line sequential horizontal driving circuit and outputting the pixel signal held in the storage capacitor of the pixel to the outside A readout circuit;
In an active matrix type liquid crystal display device provided on the same substrate,
The pixel signal readout circuit is provided on the same side of the TFT array as the line sequential horizontal driving circuit,
Each output signal from the shift register of the line-sequential horizontal driving circuit, and a selection switch for selecting a part from a plurality of reference voltage supply lines of the D / A converter of the line-sequential horizontal driving circuit, Connect via the readout switch,
The pixel signal held in the storage capacitor of the selected pixel by turning on the readout switch and each output signal of the shift register sequentially turning on the selection switch of the D / A converter. Is output from the data line to the readout line via the selection switch and a part of the reference voltage supply line of the D / A converter. The drive frequency of the pixel signal readout circuit, the line sequential system active matrix type liquid crystal according to any one of claims 1 to 3, characterized in that controlled independently of the write driving frequency of the horizontal drive circuit Display device. 2. The readout of a pixel signal from the pixel signal readout circuit to the outside and the supply of the pixel signal from the outside to the line-sequential type horizontal drive circuit are switchable via a common terminal. to an active matrix type liquid crystal display device of any one of claims 4.

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