WO2012161042A1 - 走査信号線駆動回路、それを備えた表示装置、および走査信号線の駆動方法 - Google Patents
走査信号線駆動回路、それを備えた表示装置、および走査信号線の駆動方法 Download PDFInfo
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- WO2012161042A1 WO2012161042A1 PCT/JP2012/062474 JP2012062474W WO2012161042A1 WO 2012161042 A1 WO2012161042 A1 WO 2012161042A1 JP 2012062474 W JP2012062474 W JP 2012062474W WO 2012161042 A1 WO2012161042 A1 WO 2012161042A1
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K3/00—Circuits for generating electric pulses; Monostable, bistable or multistable circuits
- H03K3/01—Details
- H03K3/012—Modifications of generator to improve response time or to decrease power consumption
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
- G09G3/3611—Control of matrices with row and column drivers
- G09G3/3674—Details of drivers for scan electrodes
- G09G3/3677—Details of drivers for scan electrodes suitable for active matrices only
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
- G09G3/3611—Control of matrices with row and column drivers
- G09G3/3696—Generation of voltages supplied to electrode drivers
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11C—STATIC STORES
- G11C19/00—Digital stores in which the information is moved stepwise, e.g. shift registers
- G11C19/28—Digital stores in which the information is moved stepwise, e.g. shift registers using semiconductor elements
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2310/00—Command of the display device
- G09G2310/02—Addressing, scanning or driving the display screen or processing steps related thereto
- G09G2310/0264—Details of driving circuits
- G09G2310/0286—Details of a shift registers arranged for use in a driving circuit
Definitions
- the present invention relates to a scanning signal line driving circuit, a display device including the scanning signal line driving method, and a scanning signal line driving method, and more particularly, to a scanning signal line driving circuit suitable for monolithic operation, a display device including the scanning signal line driving circuit,
- the present invention relates to a scanning signal line driving method by a line driving circuit.
- a gate driver for driving a gate line (scanning signal line) of a liquid crystal display device is mounted as an IC (Integrated Circuit) chip on a peripheral portion of a substrate constituting a liquid crystal panel.
- IC Integrated Circuit
- a-Si TFT a thin film transistor using amorphous silicon (a-Si)
- a-Si TFT a thin film transistor using amorphous silicon
- a-Si TFT a thin film transistor using microcrystalline silicon
- IGZO oxide semiconductor
- IGZOTFT a thin film transistor using IGZO
- ⁇ c-SiTFT and IGZOTFT have higher mobility than a-SiTFT. Therefore, by adopting ⁇ c-SiTFT or IGZOTFT as a drive element, it is possible to reduce the frame area and increase the definition of the liquid crystal display device.
- the display portion of the active matrix type liquid crystal display device includes a plurality of source lines (video signal lines), a plurality of gate lines, and intersections of the plurality of source lines and the plurality of gate lines. And a plurality of pixel formation portions provided corresponding to each. These pixel formation portions are arranged in a matrix to constitute a pixel array.
- Each pixel forming unit holds a pixel voltage value, and a thin film transistor (switching element) having a gate terminal connected to a gate line passing through a corresponding intersection and a source terminal connected to a source line passing through the intersection.
- the pixel capacity is included.
- the active matrix liquid crystal display device is also provided with the above gate driver and a source driver (video signal line driving circuit) for driving the source line.
- a video signal indicating a pixel voltage value is transmitted by a source line, but each source line cannot transmit a video signal indicating a pixel voltage value for a plurality of rows at a time (simultaneously). For this reason, the writing (charging) of the video signal to the pixel capacitors in the above-described pixel formation portion arranged in a matrix is sequentially performed row by row. Therefore, the gate driver is configured by a shift register having a plurality of stages so that a plurality of gate lines are sequentially selected for a predetermined period. Each stage of the shift register is in one of two states (first state and second state) at each time point, and is a signal indicating the state (hereinafter referred to as “state signal”). ) As a scanning signal. Then, by sequentially outputting active scanning signals from a plurality of bistable circuits in the shift register, video signals are sequentially written to the pixel capacitors row by row as described above.
- the bistable circuit in the conventional gate driver is configured as shown in FIG.
- Such a bistable circuit is disclosed in Patent Document 1, for example.
- the transistors M3 and M7 in FIG. 32 may have a multi-gate configuration as disclosed in Patent Document 1.
- the bistable circuit shown in FIG. 32 is referred to as “first conventional example”.
- the first conventional example when the scanning signal GOUT (i ⁇ 1) (set signal S) sent from the previous stage becomes high level, the transistor M3 is turned on, so that the potential of the second node N2 becomes low level. Become. Thereby, the transistors M5 and M6 are turned off. Accordingly, when the scanning signal GOUT (i ⁇ 1) becomes high level, the potential of the first node N1 becomes high level, and the capacitor C1 is charged.
- the potential of the clock signal CK appears on the gate line.
- the potential of the clock signal CK applied to each bistable circuit is set to high level, so that the shift register Active scanning signals are sequentially output from a plurality of bistable circuits.
- the plurality of gate lines are sequentially driven one by one.
- the potential of the first node N1 is maintained at a low level during a period other than a period during which an operation for outputting an active scanning signal is performed (a “normal operation period” to be described later).
- the potential of the second node N2 is maintained at a high level.
- the potential of the second node N2 needs to be maintained at a high level so that the potential of the first node N1 is maintained at a low level during the normal operation period. Therefore, during this normal operation period, a high-level potential (the potential of the second node N2) is always applied to the gate terminals of the transistors M5 and M6. Since the period during which the operation for outputting the active scanning signal is performed is small in each vertical scanning period, a substantially DC potential is applied to the gate terminals of the transistors M5 and M6. As a result, threshold fluctuations occurring in these transistors M5 and M6 increase, leading to a decrease in transistor reliability.
- Patent Document 2 includes a plurality of bistable circuits including an input unit 920, a pull-up driving unit 930, a pull-down driving unit 940, and an output unit 950, as shown in FIG. A gate driver is disclosed.
- the bistable circuit shown in FIG. 33 is referred to as a “second conventional example”.
- the input unit 920 includes a transistor T1
- the pull-up driving unit 930 includes transistors T9 and T10
- the pull-down driving unit 940 includes transistors T3, T4, T7, T8, and T11
- the output unit 950 includes It consists of transistors T1, T5, T6 and a capacitor C1.
- a second node is connected to the gate terminals of the transistors T4 and T5.
- These transistors T4 and T5 correspond to the above-described transistors M5 and M6, respectively.
- Two-phase clock signals CK1 and CK2 (duty ratio 1/4) are applied to the bistable circuit.
- the clock signal CK1 is supplied to the drain terminal of the transistor T1, the gate terminal and drain terminal of the transistor T9, and the gate terminal of the transistor T11.
- the clock signal CK1 is also applied to the gate terminal of the transistor T4 and the gate terminal of the transistor T5 via the transistor T9.
- the clock signal CK2 is supplied to the gate terminal of the transistor T8 and the gate terminal and drain terminal of the transistor T10. This clock signal CK2 is also applied to the gate terminal of the transistor T6 via the transistor T10.
- the potential of the second node N2 is at a low level during an operation for outputting an active scanning signal.
- the potential of the second node N2 becomes high level when the clock signal CK1 becomes high level, and becomes low level when the clock signal CK2 becomes high level. Therefore, a potential having a duty ratio of substantially 1 ⁇ 2 is applied to the gate terminals of the transistors T4 and T5 to which the second node N2 is connected. As a result, threshold fluctuations occurring in these transistors T4 and T5 can be suppressed, and the reliability of the transistors can be increased.
- an object of the present invention is to provide a scanning signal line driving circuit in which the reliability of a switching element is improved while reducing power consumption, a display device including the scanning signal line driving method, and a scanning signal line driving method.
- a first aspect of the present invention is a scanning signal line driving circuit for driving a plurality of scanning signal lines, A shift register that includes a plurality of bistable circuits connected in cascade, and that sequentially activates output signals of the plurality of bistable circuits based on a clock signal that is input from the outside and periodically repeats an on level and an off level With
- Each bistable circuit is A first drive unit connected to the first node and changing a potential of the first node based on a received signal; A second drive unit connected to the second node and changing the potential of the second node based on the received signal; The first node and the second node are connected to the first node and the second node, and the potential of the first node and the second node are on and off, respectively, and the potential of the signal received by the first driver is off.
- the first driving unit includes a first node turn-off switching in which the second node is connected to a control terminal, the first node is connected to one conduction terminal, and an off-level potential is applied to the other conduction terminal. Having elements, The output unit is configured such that the second node is connected to a control terminal, an output node for outputting the output signal is connected to one conduction terminal, and an off-level potential is applied to the other conduction terminal.
- the first driving unit and the second driving unit maintain the potential of the first node and the potential of the second node at an off level in a predetermined period equal to or more than two horizontal scanning periods among the vertical scanning periods, respectively. It is characterized by.
- the supply of the clock signal to the plurality of bistable circuits is stopped.
- the longer the predetermined period the higher the frequency of the clock signal.
- the first driving unit and the second driving unit further maintain the potential of the first node and the potential of the second node at an off level, respectively, after the power is turned on until the start of the first vertical scanning period, Further, the supply of the clock signal to the plurality of bistable circuits is stopped after the power is turned on until the start of the first vertical scanning period.
- the plurality of bi-stables in the predetermined period based on an end signal whose potential is turned on in order to make the output signal inactive.
- a clock control circuit for stopping supply of the clock signal to the stabilization circuit is further provided.
- the first drive unit in the final stage bistable circuit is configured such that the end signal is supplied to the control terminal, the first node is connected to one conduction terminal, and the off-level potential is given to the other conduction terminal. It further has a switching element for one end, In the second driving unit in each bistable circuit, the end signal is supplied to a control terminal, the second node is connected to one conduction terminal, and an off-level potential is given to the other conduction terminal. It has the switching element for an end, It is characterized by the above-mentioned.
- a seventh aspect of the present invention is the sixth aspect of the present invention,
- the first drive unit in the bistable circuit of each stage other than the final stage further includes the first end switching element.
- the second drive unit in the bistable circuit in each stage other than the front stage changes the potential of the second node toward the on level based on the start signal that is turned on at the start timing of each vertical scanning period. It further has a start switching element.
- a ninth aspect of the present invention is the eighth aspect of the present invention.
- the first driving unit further includes a first node turn-on switching element that changes a potential of the first node toward an on level based on a set signal,
- the set signal in the foremost stage bistable circuit is the start signal,
- the set signal in the bistable circuit other than the foremost stage is an output signal of the bistable circuit in the previous stage of the bistable circuit.
- the output unit is An output control switching element in which the first node is connected to a conduction terminal, the clock signal is applied to one conduction terminal, and the output node is connected to the other conduction terminal;
- the output control switching element further includes a capacitive element having a control terminal connected to one end and the output node connected to the other end.
- the second driving unit further includes a second node turn-off switching element in which the second node is connected to one conduction terminal and an off-level potential is applied to the other conduction terminal.
- a twelfth aspect of the present invention is the eleventh aspect of the present invention,
- the second node turn-off switching element As the second node turn-off switching element, A first second node turn-off switching element in which the set signal is applied to a control terminal, the second node is connected to one conduction terminal, and an off-level potential is applied to the other conduction terminal; There is provided a second second node turn-off switching element in which the output node is connected to a control terminal, the second node is connected to one conduction terminal, and an off-level potential is applied to the other conduction terminal. It is characterized by.
- a thirteenth aspect of the present invention is the eleventh aspect of the present invention, A control terminal of the second node turn-off switching element is connected to the first node.
- a fourteenth aspect of the present invention is the eleventh aspect of the present invention.
- the second drive unit in the bistable circuit of each stage other than the front stage changes the potential of the second node toward the on level based on the output signal of the bistable circuit subsequent to the bistable circuit. It further has a node turn-on switching element.
- the clock signal includes a first clock signal and a second clock signal that are out of phase with each other by one horizontal scanning period.
- the first clock signal is supplied to one conduction terminal of the output control switching element,
- the second driving unit may further include a charge supplement switching element that changes the potential of the second node toward an on level based on the second clock signal.
- a sixteenth aspect of the present invention is a display device, A display unit on which a plurality of scanning signal lines are arranged; A scanning signal line driving circuit that drives the plurality of scanning signal lines; and a display control circuit that supplies a clock signal that periodically repeats an on level and an off level to the scanning signal line driving circuit,
- the scanning signal line drive circuit includes a plurality of bistable circuits connected in cascade with each other, and includes a shift register that sequentially activates output signals of the plurality of bistable circuits based on the clock signal,
- Each bistable circuit is A first drive unit connected to the first node and changing a potential of the first node based on a received signal; A second drive unit connected to the second node and changing the potential of the second node based on the received signal; The first node and the second node are connected to the first node and the second node, and the potential of the first node and the second node are on and off, respectively, and the potential of the signal received by the first driver is off.
- the first driving unit includes a first node turn-off switching in which the second node is connected to a control terminal, the first node is connected to one conduction terminal, and an off-level potential is applied to the other conduction terminal. Having elements, The output unit is configured such that the second node is connected to a control terminal, an output node for outputting the output signal is connected to one conduction terminal, and an off-level potential is applied to the other conduction terminal.
- the first driving unit and the second driving unit maintain the potential of the first node and the potential of the second node at an off level in a predetermined period that is two horizontal scanning periods or more in each vertical scanning period. It is characterized by.
- a seventeenth aspect of the present invention is the sixteenth aspect of the present invention, In the predetermined period, the supply of the clock signal to the plurality of bistable circuits is stopped.
- the scanning signal line drive circuit is based on an end signal whose potential is turned on to deactivate the output signal after the output signal of the final stage bistable circuit in the shift register becomes active. It further includes a clock control circuit for stopping the supply of the clock signal to the plurality of bistable circuits during a predetermined period.
- the display control circuit stops supplying the clock signal to the plurality of bistable circuits during the predetermined period.
- the display control circuit increases the frequency of the clock signal as the predetermined period is longer.
- the display unit and the scanning signal line driving circuit are integrally formed.
- a twenty-second aspect of the present invention includes a plurality of bistable circuits cascade-connected to each other, and outputs from the plurality of bistable circuits based on a clock signal input from the outside and periodically repeating an on level and an off level.
- a method of driving a plurality of scanning signal lines by a scanning signal line driving circuit including a shift register that sequentially activates signals, Receiving a signal at each bistable circuit and changing a potential of a first node in the bistable circuit based on the signal; Receiving a signal at each bistable circuit and changing a potential of a second node in the bistable circuit based on the signal;
- the potential of the first node and the potential of the second node are on level and off level, respectively, and the potential of the signal received by each bistable circuit in the step of changing the potential of the first node is off level.
- Each bistable circuit is A first node turn-off switching element in which the second node is connected to a control terminal, the first node is connected to one conduction terminal, and an off-level potential is applied to the other conduction terminal; An output node turn-off switching element in which the second node is connected to a control terminal, an output node for outputting the output signal is connected to one conduction terminal, and an off-level potential is applied to the other conduction terminal.
- the potential of the first node is maintained at an off level in a predetermined period that is two horizontal scanning periods or more of each vertical scanning period
- the potential of the second node is maintained at an off level during the predetermined period.
- the method further includes the step of stopping the supply of the clock signal to the plurality of bistable circuits during the predetermined period.
- the longer the predetermined period the higher the frequency of the clock signal.
- the potential of the first node is further maintained at an off level between power-on and the start of the first vertical scanning period.
- the potential of the second node is further maintained at an off level between power-on and the start of the first vertical scanning period.
- the step of stopping the supply of the clock signal is characterized in that the supply of the clock signal is further stopped after the power is turned on until the start of the first vertical scanning period.
- the potential of the second node in each bistable circuit becomes an off level in a predetermined period that is two horizontal scanning periods or more in each vertical scanning period. For this reason, the duty ratio of the potential applied to the control terminal of the first node turn-off switching element and the control terminal of the output node turn-off switching element is substantially reduced as compared with the prior art. Thereby, threshold value fluctuations of the first node turn-off switching element and the output node turn-off switching element are suppressed. By increasing the reliability of the first node turn-off switching element and the output node turn-off switching element, the sizes of the first node turn-off switching element and the output node turn-off switching element can be reduced.
- the power consumption can be reduced by reducing the size of the first node turn-off switching element and the output node turn-off switching element.
- the reliability of the first node turn-off switching element and the output node turn-off switching element can be improved while reducing power consumption.
- the size of the scanning signal line driving circuit can be reduced by reducing the sizes of the first node turn-off switching element and the output node turn-off switching element.
- the supply of the clock signal to the bistable circuit is stopped during the predetermined period. Therefore, the potential of the first node and the potential of the second node are reliably maintained at a low level during the predetermined period. Thereby, the potential of the second node in each bistable circuit is reliably maintained at the off level. Therefore, the duty ratio of the potential of the second node in each bistable circuit is surely reduced as compared with the prior art. As a result, the reliability of the first node turn-off switching element and the output node turn-off switching element can be reliably increased by reliably suppressing the threshold fluctuation.
- the longer the predetermined period the higher the frequency of the clock signal. For this reason, the length of one vertical scanning period is constant. Thereby, the reliability of the first node turn-off switching element and the output node turn-off switching element can be improved without lowering the substantial drive frequency.
- the potential of the first node and the potential of the second node are reset to the off level.
- the supply of the clock signal to the bistable circuit is stopped during the period from when the power is turned on until the start of the first vertical scanning period. For this reason, the potential of the first node and the potential of the second node are reliably maintained at the off level. Thereby, the circuit operation can be further stabilized.
- the clock control circuit controls the supply of the clock signal to the bistable circuit based on the end signal. For this reason, the supply of the clock signal is reliably controlled. Thereby, the circuit operation can be stabilized.
- the potential of the second node in each bistable circuit is reliably set to the off level at the start of the vertical blanking period, and at least the final stage The potential of the first node in the bistable circuit is surely set to the off level.
- the duty ratio of the potential applied to the control terminal of the first node turn-off switching element and the control terminal of the output node turn-off switching element can be reliably reduced as compared with the prior art, and the circuit operation can be further stabilized.
- the potential of the first node in each bistable circuit is reliably turned off at the start of the vertical blanking period.
- the duty ratio of the potential applied to the control terminal of the first node turn-off switching element and the control terminal of the output node turn-off switching element can be more reliably reduced than before, and the circuit operation can be further stabilized. it can.
- the potential of the second node of the bistable circuit other than the first stage is reliably turned on by the start signal. Thereby, the circuit operation can be further stabilized.
- the potential of the first node is reliably set to the on level based on the set signal. Thereby, the circuit operation can be further stabilized.
- the output signal based on the clock signal is reliably output based on the potential of the first node and the potential of the second node. Thereby, the circuit operation can be further stabilized.
- the potential of the second node can be reliably maintained at the on level or the off level. Thereby, the circuit operation can be further stabilized.
- the potential of the second node can be more reliably maintained at the off level. Thereby, the circuit operation can be further stabilized.
- the potential of the second node is reliably set to the on level based on the reset signal. Thereby, the circuit operation can be further stabilized.
- the second node in the period other than the period in which the operation for outputting the active output signal is performed, the second node The potential increases. For this reason, the potential of the second node can be reliably maintained at a high level in a period other than the period in which an operation for outputting an active output signal is performed. Thereby, the circuit operation can be further stabilized.
- the display device has effects similar to those of the first aspect, the second aspect, and the third aspect of the present invention, respectively. Can play.
- the supply of the clock signal can be reliably stopped on the scanning signal line drive circuit side.
- the supply of the clock signal can be reliably stopped on the display control circuit side.
- the frame area of the display device can be reduced.
- the scanning signal line driving method can achieve the same effects as the first to fourth aspects of the present invention, respectively.
- FIG. 1 is a block diagram illustrating an overall configuration of a liquid crystal display device according to a first embodiment of the present invention. It is a block diagram for demonstrating the structure of the gate driver in the said 1st Embodiment. It is a block diagram which shows the structure of the shift register in the said 1st Embodiment. It is a block diagram which shows the structure of the forefront stage side of the shift register in the said 1st Embodiment. It is a block diagram which shows the structure by the side of the last stage of the shift register in the said 1st Embodiment. It is a signal waveform diagram for demonstrating operation
- FIG. 3 is a block diagram showing a configuration of a clock control circuit in the first embodiment. It is a circuit diagram which shows the structure of the 1st control signal generation circuit in the said 1st Embodiment.
- FIG. 3 is a circuit diagram showing a configuration of a second control signal generation circuit in the first embodiment.
- FIG. 2 is a circuit diagram showing a configuration of a clock output circuit in the first embodiment. It is a signal waveform diagram for demonstrating operation
- FIG. 6 is a circuit diagram showing a configuration of a bistable circuit other than the foremost stage and the last stage in the first modification of the first embodiment. It is a circuit diagram which shows the structure of the bistable circuit of the front
- the gate terminal of the thin film transistor corresponds to the control terminal
- the drain terminal corresponds to one conduction terminal
- the source terminal corresponds to the other conduction terminal.
- all the thin film transistors provided in the bistable circuit are n-channel type.
- FIG. 1 is a block diagram showing the overall configuration of an active matrix liquid crystal display device according to a first embodiment of the present invention.
- this liquid crystal display device is common to a power supply 100, a DC / DC converter 110, a display control circuit 200, a source driver (video signal line driving circuit) 300, and a gate driver (scanning signal line driving circuit) 400.
- An electrode driving circuit 500 and a display unit 600 are provided.
- the gate driver 400 is formed over a display panel including the display portion 600 using amorphous silicon, polycrystalline silicon, microcrystalline silicon, an oxide semiconductor (eg, IGZO), or the like. That is, in this embodiment, the gate driver 400 and the display unit 600 are formed on the same substrate (an array substrate that is one of the two substrates constituting the liquid crystal panel). Thereby, the frame area of the liquid crystal display device can be reduced.
- the display unit 600 includes n source lines (video signal lines) SL1 to SLn, m gate lines (scanning signal lines) GL1 to GLm, and intersections of these source lines SL1 to SLn and gate lines.
- a pixel circuit including m ⁇ n pixel forming portions provided in correspondence with each other is formed. The plurality of pixel forming portions are arranged in a matrix to form a pixel array.
- Each pixel forming portion includes a thin film transistor 80 which is a switching element having a gate terminal connected to a gate line passing through a corresponding intersection and a source terminal connected to a source line passing through the intersection, and a drain terminal of the thin film transistor 80
- a common electrode Ec that is a common electrode provided in common to the plurality of pixel formation portions, and a common electrode Ec provided in common to the plurality of pixel formation portions.
- a pixel capacitor Cp is constituted by a liquid crystal capacitor formed by the pixel electrode and the common electrode Ec.
- an auxiliary capacitor is provided in parallel with the liquid crystal capacitor in order to reliably hold the voltage in the pixel capacitor Cp.
- the auxiliary capacitor is not directly related to the present invention, its description and illustration are omitted.
- the power supply 100 supplies a predetermined power supply voltage to the DC / DC converter 110, the display control circuit 200, and the common electrode drive circuit 500.
- the DC / DC converter 110 generates a predetermined DC voltage for operating the source driver 300 and the gate driver 400 from the power supply voltage and supplies it to the source driver 300 and the gate driver 400.
- the common electrode drive circuit 500 gives a predetermined potential Vcom to the common electrode Ec.
- the display control circuit 200 receives an image signal DAT and a timing signal group TG such as a horizontal synchronization signal and a vertical synchronization signal sent from the outside, and receives a digital video signal DV and a source start pulse for controlling image display on the display unit 600.
- a signal SSP, a source clock signal SCK, a latch strobe signal LS, a gate start pulse signal GSP, a gate end pulse signal GEP, and a gate clock signal GCKf (hereinafter referred to as “gate clock signal before control”) are output.
- the pre-control gate clock signal GCK is a two-phase clock signal GCKf1 (hereinafter referred to as “first gate clock signal before control”) and a clock signal GCKf2 (hereinafter referred to as “pre-control second gate clock signal”). It consists of).
- the high-level potential of the pre-control gate clock signal GCKf is Vdd, and the low-level potential is Vss.
- the source driver 300 receives the digital video signal DV, the source start pulse signal SSP, the source clock signal SCK, and the latch strobe signal LS output from the display control circuit 200, and receives the video signal SS (1) on the source lines SL1 to SLn, respectively. Apply ⁇ SS (n).
- the gate driver 400 Based on the gate start pulse signal GSP, the gate end pulse signal GEP, and the pre-control gate clock signal GCKf output from the display control circuit 200, the gate driver 400 generates active scan signals GOUT (1) to GOUT (m). The application to each of the gate bus lines GL1 to GLm is repeated with one vertical scanning period as a cycle. A detailed description of the gate driver 400 will be given later.
- the video signals SS (1) to SS (n) are applied to the source lines SL1 to SLn, respectively, and the scanning signals GOUT (1) to GOUT (m) are applied to the gate lines GL1 to GLm, respectively.
- the display unit 600 an image based on the image signal DAT sent from the outside is displayed on the display unit 600.
- FIG. 2 is a block diagram for explaining the configuration of the gate driver 400 in this embodiment.
- the gate driver 400 includes a shift register 410 and a clock control circuit 420 including m (stage) bistable circuits 40 (1) to 40 (m).
- the clock control circuit 420 receives the gate start pulse signal GSP, the gate end pulse signal GEP, and the pre-control gate clock signal GCKf, and is a gate clock that is a signal obtained by stopping the pre-control gate clock signal GCKf for a certain period.
- a signal GCK (hereinafter referred to as “post-control gate clock signal”) is supplied to the shift register 410.
- post-control gate clock signal A detailed description of the clock control circuit 420 will be given later.
- the display unit 600 is formed with a pixel matrix of m rows ⁇ n columns as described above, and the bistable circuit is provided at each stage so as to correspond to each row of these pixel matrices on a one-to-one basis.
- This bistable circuit is in any one of two states (first state and second state) at each time point, and a signal indicating the state (hereinafter referred to as “state signal”). Output.
- a high level (on level) state signal is output from the bistable circuit
- the bistable circuit is in the second state.
- a low level (off level) state signal is output from the bistable circuit.
- selection period a period during which a high-level state signal is output from the bistable circuit and a high-level scanning signal is applied to the gate line corresponding to the bistable circuit.
- FIG. 3 is a block diagram showing a configuration of the shift register 410 other than the first and last stages in the present embodiment.
- FIG. 4 is a block diagram showing a configuration on the forefront side of the shift register 410 in the present embodiment.
- FIG. 5 is a block diagram showing a configuration on the last stage side of the shift register 410 in the present embodiment.
- the shift register 410 includes m bistable circuits 40 (1) to 40 (m).
- FIG. 3 shows the i-2 stage 40 (i-2) to i + 1 stage 40 (i + 1)
- FIG. 4 shows the first stage 40 (1) and the second stage 40 (2)
- the m-1 stage 40 (m-1) and the m stage 40 (m) are shown.
- each bistable circuit has an input terminal for receiving the clock signal CKA, an input terminal for receiving the clock signal CKB, and a low-level DC power supply potential Vss (of this potential). The magnitude is also referred to as “Vss potential”.)
- the clock signal CKA is referred to as an “operation control clock signal”
- the clock signal CKB is referred to as a “charge replenishment clock signal”.
- Each stage except the m-th stage (last stage) is further provided with an input terminal for receiving the reset signal R.
- Each stage excluding the first stage (frontmost stage) is further provided with an input terminal for receiving the start signal ST.
- the shift register 410 includes a two-phase clock signal GCK1 (hereinafter referred to as “first gate clock signal after control”) and a clock signal GCK2 (hereinafter referred to as “second gate clock signal after control”) as a gate clock signal GCK after control. Is given.
- first gate clock signal after control a clock signal
- second gate clock signal after control a clock signal GCK2
- the post-control first gate clock signal GCK1 and the post-control second gate clock signal GCK2 are out of phase with each other by one horizontal scan period, and both are one horizontal scan period in the two horizontal scan periods. Only a high level (Vdd level) is obtained (except for a vertical blanking period described later).
- each stage each bistable circuit of the shift register 410
- i and m are even numbers.
- the first gate clock signal GCK1 after control is given as the operation control clock signal CKA
- the second gate clock signal GCK2 after control is the clock signal CKB for charge replenishment.
- the controlled first gate clock signal GCK1 is supplied as the charge replenishment clock signal CKB
- the controlled second gate clock signal GCK2 is supplied as the operation control clock signal CKA.
- the state signal Q output from the previous stage is supplied as the set signal S and the state signal Q output from the next stage is supplied as the reset signal R to both the odd and even stages.
- the gate start pulse signal GSP is supplied as the set signal S to the first stage (frontmost stage) 40 (1).
- the reset signal R is not given to the m-th stage (last stage) 40 (m).
- Each stage is commonly supplied with the gate end pulse signal GEP as the end signal ED and is commonly supplied with the low-level DC power supply potential Vss.
- the gate start pulse signal GSP is given as a start signal to each stage except the first stage 40 (1).
- the gate start pulse signal GSP as the set signal S is given to the first stage 40 (1) of the shift register 410, the controlled first gate clock signal GCK1 and the controlled second gate clock signal Based on GCK2, pulses included in the gate start pulse signal GSP (this pulse is included in the status signal Q output from each stage) are sequentially transferred from the first stage 40 (1) to the mth stage 40 (m).
- the status signals Q output from the first stage 40 (1) to the m-th stage 40 (m) are sequentially set to the high level.
- the state signals Q output from the first stage 40 (1) to m-th stage 40 (m) are respectively applied to the gate lines GL1 to GLm as scanning signals GOUT (1) to GOUT (m).
- the state signals Q output from the first stage 40 (1) to the m-th stage 40 (m) are increased in voltage by the level shifter, and then used as scanning signals GOUT (1) to GOUT (m) as gate lines. It may be given to each of GL1 to GLm. As described above, as shown in FIG. 6, a scanning signal that sequentially becomes high level (active) for each horizontal scanning period is supplied to the gate line in the display portion 600. The detailed operation of the gate driver 400 will be described later.
- FIG. 7 is a circuit diagram showing a configuration of a bistable circuit other than the first stage (frontmost stage) and the mth stage (last stage) in the present embodiment.
- the bistable circuit includes a first drive unit 61, a second drive unit 62, and an output unit 63.
- This bistable circuit is provided with six input terminals 41 to 44, 46 and 47 and one output terminal (output node) 51 in addition to the input terminal for the low-level DC power supply potential Vss. ing.
- the input terminal that receives the set signal S is denoted by reference numeral 41
- the input terminal that receives the reset signal R is denoted by reference numeral 42
- the input terminal that receives the end signal ED is denoted by reference numeral 43
- the start signal The input terminal that receives ST is denoted by reference numeral 44
- the input terminal that receives the operation control clock signal CKA is denoted by reference numeral 46
- the input terminal that receives the charge replenishment clock signal CKB is denoted by reference numeral 47.
- An output terminal for outputting the status signal Q is denoted by reference numeral 51.
- the first driving unit 61 includes three thin film transistors M1, M5, and MA.
- the second drive unit 62 includes six thin film transistors M3, M4, M7 to M9, and MB, and one capacitor C2.
- the output unit 63 includes two thin film transistors M2 and M6 and one capacitor C1.
- the source terminal of the thin film transistor M1, the gate terminal of the thin film transistor M2, the drain terminal of the thin film transistor M5, and one end of the capacitor C1 are connected to each other.
- a connection point (wiring) where these are connected to each other is referred to as a “first node” for convenience.
- connection point where these are connected to each other is referred to as a “second node” for convenience.
- the first node is denoted by reference numeral N1
- the second node is denoted by reference numeral N2.
- the source terminal of the thin film transistor M1, the drain terminal of the thin film transistor M5, and the drain terminal of the thin film transistor MA provided in the first drive unit 61 are connected to the first node N1.
- the drain terminal of the thin film transistor M3, the drain terminal of the thin film transistor M4, the source terminal of the thin film transistor M7, the source terminal of the thin film transistor M8, the source terminal of the thin film transistor M9, the drain terminal of the thin film transistor MB, and the capacitor C2 Is connected to the second node N2.
- the gate terminal of the thin film transistor M2 provided in the output unit 63 and one end of the capacitor C1 are connected to the first node N1, and the gate terminal of the thin film transistor M6 is connected to the second node N2.
- the gate terminal and the drain terminal are connected to the input terminal 41 (that is, diode connection), and the source terminal is connected to the first node N1.
- the gate terminal is connected to the first node N1
- the drain terminal is connected to the input terminal 46
- the source terminal is connected to the output terminal 51.
- the gate terminal is connected to the input terminal 41, the drain terminal is connected to the second node N2, and the source terminal is connected to the input terminal for the DC power supply potential Vss.
- the gate terminal is connected to the output terminal 51, the drain terminal is connected to the second node N2, and the source terminal is connected to the input terminal for the DC power supply potential Vss.
- the gate terminal is connected to the second node N2, the drain terminal is connected to the first node N1, and the source terminal is connected to the input terminal for the DC power supply potential Vss.
- the gate terminal is connected to the second node N2, the drain terminal is connected to the output terminal 51, and the source terminal is connected to the input terminal for the DC power supply potential Vss.
- the gate terminal and the drain terminal are connected to the input terminal 42 (that is, diode connection), and the source terminal is connected to the second node N2.
- the gate terminal and the drain terminal are connected to the input terminal 44 (that is, diode connection), and the source terminal is connected to the second node N2.
- the gate terminal and the drain terminal are connected to the input terminal 47 (that is, diode connection), and the source terminal is connected to the second node N2.
- the gate terminal is connected to the input terminal 43, the drain terminal is connected to the first node N1, and the source terminal is connected to the input terminal for the DC power supply potential Vss.
- the gate terminal is connected to the input terminal 43, the drain terminal is connected to the second node N2, and the source terminal is connected to the input terminal for the DC power supply potential Vss.
- the capacitor C1 has one end connected to the first node and the other end connected to the output terminal 51.
- the capacitor C2 has one end connected to the second node N2 and the other end connected to the input terminal for the DC power supply potential Vss.
- the thin film transistor M1 changes the potential of the first node N1 toward the high level when the potential of the set signal S is at the high level.
- the thin film transistor M2 gives the potential of the operation control clock signal CKA to the output terminal 51 when the potential of the second node N2 is at a high level.
- the thin film transistor M3 changes the potential of the second node N2 toward the Vss potential when the potential of the set signal S is at a high level.
- the thin film transistor M4 changes the potential of the second node N2 toward the Vss potential when the potential of the state signal Q (the potential of the output terminal 51) is at a high level.
- the thin film transistor M5 changes the potential of the first node N1 toward the Vss potential when the potential of the second node N2 is at a high level.
- the thin film transistor M6 changes the potential of the output terminal 51 toward the Vss potential when the potential of the second node N2 is at a high level.
- the thin film transistor M7 changes the potential of the second node N2 toward the high level when the potential of the reset signal R is at the high level.
- the thin film transistor M8 changes the potential of the second node N2 toward the high level when the potential of the start signal ST is at the high level.
- the thin film transistor M9 changes the potential of the second node N2 toward the high level when the potential of the charge supplement clock signal CKB is at the high level.
- the thin film transistor MA changes the potential of the first node N1 toward the Vss potential when the end signal ED is at a high level.
- the thin film transistor MB changes the potential of the second node N2 toward the Vss potential when the end signal ED is at a high level.
- the capacitor C1 functions as a compensation capacitor for maintaining the potential of the first node at a high level during the period when the gate line connected to the bistable circuit is in a selected state.
- the capacitor C2 functions as a compensation capacitor for maintaining the potential of the second node N2 at a high level during a normal operation period.
- FIG. 8 is a circuit diagram showing a configuration of a first stage (frontmost stage) bistable circuit in the present embodiment. As shown in FIG. 8, this bistable circuit is provided with a thin film transistor M8 and an input terminal 44, unlike the bistable circuit other than the first stage (frontmost stage) and the mth stage (last stage) shown in FIG. Not.
- the other configuration of this bistable circuit is the same as that of the bistable circuit other than the first stage (frontmost stage) and the mth stage (last stage) shown in FIG.
- FIG. 9 is a circuit diagram showing a configuration of the m-th (last stage) bistable circuit in the present embodiment. As shown in FIG. 9, this bistable circuit is provided with a thin film transistor M7 and an input terminal 42, unlike the bistable circuit other than the first stage (frontmost stage) and the mth stage (last stage) shown in FIG. Not.
- the other configuration of this bistable circuit is the same as that of the bistable circuit other than the first stage (frontmost stage) and the mth stage (last stage) shown in FIG.
- the first node turn-on switching element is realized by the thin film transistor M1
- the output control switching element is realized by the thin film transistor M2
- the first second node turn-off switching element is realized by the thin film transistor M3, and the thin film transistor.
- a second second node turn-off switching element is realized by M4
- a first node turn-off switching element is realized by the thin film transistor M5
- an output node turn-off switching element is realized by the thin film transistor M6
- a second node turn-on is realized by the thin film transistor M7.
- Switching element is realized, the switching element for start is realized by the thin film transistor M8, and the electric current is supplied by the thin film transistor M9.
- Supplementary switching element is realized, first end switching elements is realized by the thin film transistor MA, the second end switching element is realized by a thin film transistor MB.
- a capacitor element is realized by the capacitor C1.
- FIG. 10 is a signal waveform diagram for explaining the operation of the i-th stage bistable circuit 40 (i) in this embodiment. Since other bistable circuits operate in the same manner, the description thereof is omitted.
- the period from time t1 to time t2 corresponds to the selection period.
- one horizontal scanning period immediately before the selection period is referred to as a “set period”
- one horizontal scanning period immediately after the selection period is referred to as a “reset period”.
- a period from a time when the start signal ST (gate start pulse signal GSP) rises to a time when the end signal ED (gate end pulse signal GEP) rises is referred to as a “writing period”.
- a period (predetermined period) from the time when the end signal ED rises to the time when the start signal ST rises in the subsequent vertical scanning period in one vertical scanning period is referred to as a “vertical blanking period”.
- a period in which the end signal ED is at a low level is particularly referred to as a “pause period”.
- a period other than the selection period, the set period, and the reset period in the writing period is referred to as a “normal operation period”.
- the potential of the second node N2 is maintained at a high level. Therefore, the thin film transistors M5 and M6 are in an on state. Since there is a parasitic capacitance between the gate and drain of the thin film transistor M2, noise occurs at the first node N1 due to fluctuations in the waveform of the first clock CK1 for operation control (see FIG. 10), but the thin film transistor M5 is in the on state. Therefore, the potential of the first node N1 is pulled to a low level.
- the potential of the charge replenishment clock signal CKB repeats a high level and a low level every horizontal period, so that the thin film transistor M9 is turned on in one horizontal period every two horizontal scanning periods. For this reason, charges are supplied to the second node N2 via the thin film transistor M9.
- the potential of the second node N2 increases during the period when the charge supplement clock signal CKB is at the high level.
- the capacitor C2 is charged. Therefore, in the normal operation period, the potential of the second node N2 is reliably maintained at a high level.
- the set signal S changes from low level to high level. Since the thin film transistor M1 is diode-connected as shown in FIG. 7, when the set signal S goes high, the thin film transistor M1 is turned on and the capacitor C1 is charged (here, precharged). As a result, the potential of the first node N1 changes from the low level to the high level, and the thin film transistor M2 is turned on. However, since the potential of the operation control clock signal CKA is at a low level during the set period, the potential of the state signal Q is maintained at a low level. Further, when the set signal S becomes high level, the thin film transistor M3 is turned on. For this reason, the potential of the second node N2 becomes low level. Accordingly, the thin film transistors M5 and M6 are turned off.
- the set signal S changes from high level to low level.
- the thin film transistor M1 is turned off.
- the thin film transistor M5 is in an off state. Therefore, the first node N1 is in a floating state.
- the potential of the operation control clock signal CKA changes from the low level to the high level.
- the potential of the first node N1 also increases with the increase of the potential of the input terminal 46 (the first node N1 is bootstrapped). ).
- the thin film transistor M2 is completely turned on, and the potential of the state signal Q rises to a level sufficient to select the gate line connected to the output terminal 51 of the bistable circuit.
- the output unit 63 has a signal (thin film transistor) in which the potentials of the first node N1 and the second node N2 are high level (on level) and low level (off level), respectively, and the first driving unit 61 receives.
- the set signal S which is a signal given to M1
- the thin film transistor M4 is turned on when the potential of the state signal Q becomes high level, the potential of the second node N2 is surely low level. Accordingly, the thin film transistors M5 and M6 are reliably maintained in the off state during the selection period.
- the potential of the operation control clock signal CKA changes from high level to low level. Since the thin film transistor M2 is in the on state at the time point t4, the potential of the state signal Q decreases as the potential of the input terminal 43 decreases. As the potential of the state signal Q decreases in this way, the potential of the first node N1 also decreases via the capacitor C1. During this period, the reset signal R changes from the low level to the high level. Therefore, the thin film transistor M7 is turned on, and the potential of the second node N2 becomes high level. Thereby, the thin film transistors M5 and M6 are turned on.
- the potential of the first node N1 and the potential of the state signal Q are lowered to a low level. Further, since the capacitor C2 is charged as the potential of the second node N2 rises, the potential (high level) of the second node N2 is maintained even after the reset period.
- the end signal Ed changes from the low level to the high level in the reset period, whereby the thin film transistors M5 and M6 are turned on. As a result, also in the m-th stage bistable circuit 40 (m), the potential of the first node N1 and the potential of the state signal Q are lowered to the low level during the reset period.
- FIG. 11 is a block diagram showing a configuration of the clock control circuit 420 in the present embodiment.
- the clock control circuit 420 is provided in the gate driver 400 as described above.
- the clock control circuit 420 includes a first control signal generation circuit 71, a second control signal generation circuit 72, and a clock output circuit 73.
- the first control signal generation circuit 71 is supplied with the gate start pulse signal GSP and the gate end pulse signal GEP from the display control circuit 200.
- the first control signal generation circuit 71 generates and outputs a first control signal CT based on the received gate start pulse signal GSP and gate end pulse signal GEP.
- the first control signal generation circuit 71 is realized by an RS latch circuit, for example, as shown in FIG.
- the first control signal generation circuit 71 receives the gate start pulse signal GSP and the gate end pulse signal GEP as the set signal S and the reset signal R, respectively, and outputs the first control signal CT1 as the state signal Q.
- the second control signal generation circuit 72 is supplied with the first control signal CT from the first control signal generation circuit 71 and the gate start pulse signal GSP from the display control circuit 200.
- the second control signal generation circuit 72 generates and outputs a second control signal CT2 based on the received first control signal CT and gate start pulse signal GSP.
- the second control signal generation circuit 72 is realized by an XOR (exclusive OR) circuit, for example, as shown in FIG.
- the second control signal generation circuit 72 receives the first control signal CT1 and the gate end pulse signal GEP as a first input and a second input, respectively, and outputs a second control signal CT2.
- the clock output circuit 73 is supplied with the pre-control gate clock signal GCKf (the pre-control first gate clock signal GCKf1 and the pre-control second gate clock signal GCKf2) from the display control circuit 200 and from the second control signal generation circuit 72.
- a second control signal CT is provided.
- the clock output circuit 73 generates a post-control gate clock signal GCK (a post-control first gate clock signal GCK1 and a post-control second gate clock signal GCK2) based on the received pre-control gate clock signal GCKf and the second control signal CT. Is generated and output.
- the clock output circuit 73 is realized by two AND circuits 73a and 73b, for example, as shown in FIG.
- one of the two AND circuits 73a is referred to as a “first AND circuit”, and the other AND circuit 73b is referred to as a “second AND circuit”.
- the first AND circuit 73a receives the pre-control first gate clock signal GCKf1 and the second control signal CT2, and outputs a logical product of these before the control as the first gate clock signal GCK1.
- the second AND circuit 73b receives the pre-control second gate clock signal GCKf2 and the second control signal CT2, and outputs the logical product of these as the second gate clock signal GCK2 after control.
- the post-control first gate clock signal GCK1 and the post-control second gate clock signal GCK2 respectively output from the first AND circuit 73a and the second AND circuit 73b are applied to each bistable circuit in the shift register 410.
- the configuration of the clock control circuit 420 described above is merely an example, and the present invention is not limited to this.
- FIG. 15 is a signal waveform diagram for explaining the operation of the clock control circuit 420 in the present embodiment. As shown in FIG. 15, the pre-control first gate clock signal GCK1f and the pre-control second gate clock signal GCKf2 periodically repeat a high level and a low level.
- the gate start pulse signal GSP changes from the low level to the high level.
- the gate end pulse signal GEP is at a low level.
- the set signal of the first control signal generation circuit 71 shown in FIG. 12 is at a high level, and the reset signal R is at a low level.
- the first control signal CT1 which is the state signal Q of the first control signal generation circuit 71
- the first input of the second control signal generation circuit 72 shown in FIG. 13 becomes high level
- the post-control first gate clock signal GCK1 and the post-control second gate clock signal GCK2 become low level. That is, at this time, the supply of the pre-control gate clock signal GCKf to each bistable circuit is stopped.
- the gate start pulse signal GSP changes from high level to low level.
- the gate end pulse signal GEP is at a low level.
- the set signal of the first control signal generation circuit 71 shown in FIG. 12 is low level, and the reset signal R is low level. Therefore, as shown in FIG. 15, the first control signal CT1, which is the state signal Q of the first control signal generation circuit 71, maintains the high level that is the previous state (the state at the time point ta).
- the first input of the second control signal generation circuit 72 shown in FIG. 13 becomes high level, and the second input becomes low level. Therefore, as shown in FIG. 15, the second control signal CT2 that is the output of the second control signal generation circuit 72 is at a high level.
- the pre-control first gate clock signal GCKf1 and the pre-control second gate clock signal GCKf2 are output as the post-control first gate clock signal GCK1 and the post-control second gate clock signal GCK2, respectively. That is, at this time, the pre-control gate clock signal GCKf is supplied to each bistable circuit. This state is maintained until the gate end pulse signal GEP changes from low level to high level (until time tc).
- the gate end pulse signal GEP changes from the low level to the high level.
- the gate start pulse signal GSP is at a low level.
- the set signal of the first control signal generation circuit 71 shown in FIG. 12 is low level, and the reset signal R is high level. Therefore, as shown in FIG. 15, the first control signal CT1, which is the state signal Q of the first control signal generation circuit 71, is at a low level.
- the first input of the second control signal generation circuit 72 shown in FIG. 13 becomes low level, and the second input becomes low level. Therefore, as shown in FIG. 15, the second control signal CT2 that is the output of the second control signal generation circuit 72 is at a low level.
- the post-control first gate clock signal GCK1 and the post-control second gate clock signal GCK2 become low level. That is, at this time, the supply of the pre-control gate clock signal GCKf to each bistable circuit is stopped. This state is maintained until the gate start pulse signal GSP changes from the high level to the low level (until time td) in the writing period of the subsequent vertical scanning period.
- the gate start pulse signal GSP (start signal ST) rises in the subsequent vertical scanning period from the time when the gate end pulse signal GEP (end signal ED) falls.
- the vertical blanking period which is the period up to the time point, both the controlled first gate clock signal GCK1 and the controlled second gate clock signal GCK2 are at a low level. That is, in the vertical blanking period, the supply of the first gate clock signal GCKf1 before control and the second gate clock signal GCKf2 before control to each bistable circuit is stopped.
- the operation of the clock control circuit 420 described above is merely an example, and the present invention is not limited to this.
- FIG. 16 is a signal waveform diagram for explaining the detailed operation of the gate driver 400 in this embodiment.
- one vertical scanning period is described as being driven at a general driving frequency of 60 Hz (about 16.7 msec).
- a vertical blanking period (about 8.3 msec) having a length of about 1 ⁇ 2 of one vertical scanning period is provided.
- the driving frequency in the writing period is 120 Hz (about 8.3 msec), which is double the general driving frequency. That is, in the present embodiment, the length of the writing period and the length of the vertical blanking period are substantially equal to each other.
- the first node N1 in the first stage 40 (1) to the m-th stage 40 (m) is represented by reference numerals N1 (1) to N1 (m), respectively, and the second node N2 is represented respectively.
- Reference numerals N2 (1) to N2 (m) are used.
- the first nodes N1 (1) to N1 (m) are respectively referred to as “first-stage first node to m-th stage first node”, and the second nodes N2 (1) to N2 (m) are respectively referred to as “1”. It is referred to as “second stage node to m-th stage second node”.
- the potential of the gate start pulse signal GSP which is the set signal S in the first stage 40 (1)
- Node N1 (1) is precharged.
- the thin film transistor M3 is turned on, and the first-stage second node N2 (1) is maintained at the low level.
- the potential of the first gate clock signal GCK1 after control and the potential of the second gate clock signal GCK2 after control are at a low level. Further, as the potential of the gate start pulse signal GSP changes from the low level to the high level, as shown in FIGS.
- the thin film transistor M8 in the second stage 40 (2) to the m stage 40 (m) Turns on. For this reason, the potentials of the second-stage second node N2 (2) to the m-th stage N2 (m) change from the low level to the high level. In this way, the potentials of the second-stage second node N2 (2) to the m-th stage N2 (m) become high level, so that the second-stage first node N1 (2) to the m-th stage N1 (m) Can be reliably maintained at a low level.
- the first gate after control which is the operation control clock signal CKA of the first stage 40 (1).
- the first-stage first node N1 (1) is bootstrapped.
- the potential of the scanning signal GOUT (1) of the first stage 40 (1) becomes high level (active).
- the potential of the scanning signal GOUT (1) of the first stage 40 (1) which is the set signal S, changes from the low level to the high level. Node N1 (2) is precharged.
- the thin film transistor M3 since the set signal S changes from the low level to the high level, the thin film transistor M3 is turned on, and the potential of the second-stage second node N2 (2) changes from the high level to the low level.
- the first stage 40 (1) Since the potential of the scanning signal line GOUT (2) of the second stage 40 (2) as the reset signal R changes from the low level to the high level, the potential of the first stage second node N2 (1) changes from the low level to the high level. Change to level. As a result, the potential of the first-stage first node N1 (1) changes from the high level to the low level. Therefore, the potential of the scanning signal GOUT (1) of the first stage 40 (1) changes from the high level to the low level.
- the potential (high level) of the first-stage second node N2 (1) is maintained until the end of the writing period (the time when the gate end pulse signal GEP rises).
- the second-stage first node N1 (2) is changed by changing the potential of the second gate clock signal GCK2 after the control, which is the operation control clock signal CKA, from the low level to the high level. ) Is bootstrapped.
- the potential of the scanning signal line GOUT (1) in the second stage 40 (2) becomes high level (active).
- the scanning signal GOUT (2) of the second stage 40 (2) which is the set signal S, changes from the low level to the high level, so that the third stage first node N1 (3) Precharged.
- the set signal S changes from the low level to the high level, the thin film transistor M3 is turned on, and the potential of the third-stage second node N2 (3) changes from the high level to the low level.
- the same operation is performed for each horizontal scanning period in each stage except the m-th stage 40 (m) until the end of the writing period.
- the thin film transistor M7 and the input terminal 42 are not provided as described above. Therefore, the operation for changing the scanning signal GOUT (m) from the high level to the low level at the m-th stage 40 (m) is based on the end signal ED (gate end pulse signal GEP) instead of the reset signal R. Done.
- the operation for changing the scanning signal from the high level to the low level in the reset period of each stage is referred to as “reset operation”.
- the reset operation of the m-th stage 40 (m) is performed in the first horizontal scanning period in the vertical blanking period.
- the gate end pulse signal GEP changes from the low level to the high level. Therefore, the thin film transistors MA and MB are turned on at each stage that receives the gate end pulse signal GEP as the end signal ED. As a result, the potential of the first-stage first node N1 (1) to the (m ⁇ 1) -th stage first node N1 (m ⁇ 1) is reliably maintained at a low level, and the first-stage second node N2 (1) ) ⁇ m ⁇ 1 stage second node N2 (m ⁇ 1) potential changes from high level to low level.
- the potential of the m-th stage first node N1 (m) changes from the high level to the low level, and thus the scanning signal GOUT (m) Changes from a high level to a low level.
- the reset operation is performed based on the end signal ED.
- the thin film transistors MA and MB are turned on, so that the potential of the m-th stage second node N2 (m) is maintained at a low level.
- the clock control circuit 420 stops the supply of the pre-control first gate clock signal GCKf1 and the pre-control second gate clock signal GCKf2. That is, the potentials of the first gate clock signal GCK1 after control and the second gate clock signal GCK2 after control become low level.
- the gate end pulse signal GEP changes from a high level to a low level in the vertical blanking period (when it enters a rest period)
- the thin film transistors MA and MB in each stage are turned off. All the other thin film transistors are also turned off. For this reason, the first node N1 and the second node N2 are in a floating state in each stage.
- the potentials of the first gate clock signal GCK1 after control and the second gate clock signal GCK2 after control are at the low level as described above.
- the potential of the input terminal 46 does not fluctuate, the potential fluctuation of the first node N1 due to the parasitic capacitance between the gate and the drain of the thin film transistor M2 in which the input terminal 46 is connected to the drain terminal does not occur. .
- the potential fluctuation of the second node N2 due to the parasitic capacitance between the gate and the drain of the thin film transistor M9 in which the input terminal 47 is connected to the drain terminal does not occur.
- the potential of the first node N1 and the potential of the second node N2 in each stage are reliably maintained at a low level.
- the potentials of all signals given to the m bistable circuits, the potential of the first node N1 in each stage, and the potential of the second node N2 become low level. A period is provided.
- the potential of the second node N2 in each stage becomes a high level in the writing period excluding the set period and the selection period of the stage, and the set period and the selection of the stage. It becomes low level during the period and the vertical blanking period including the pause period. Further, the length of the vertical blanking period is about 1 ⁇ 2 of one vertical scanning period. For this reason, the duty ratio of the potential of the second node N2 in each stage is substantially 1 ⁇ 2. That is, the duty ratio of the potential applied to the gate terminal of the thin film transistor M5 and the gate terminal of the thin film transistor M6 is substantially 1 ⁇ 2. Thereby, threshold value fluctuations of these thin film transistors M5 and M6 are suppressed.
- the reliability of the thin film transistors M5 and M6 can be improved.
- the sizes of the thin film transistors M5 and M6 can be reduced.
- power consumption can be reduced.
- the reliability of the thin film transistors M5 and M6 can be increased while reducing power consumption.
- the frame area of the liquid crystal display device can be reduced by reducing the sizes of the thin film transistors M5 and M6.
- the supply of the pre-control first gate clock signal GCKf1 and the pre-control second gate clock signal GCKf2 is stopped, so that the first node N1 in each stage The potential and the potential of the second node N2 are reliably maintained at a low level. For this reason, the duty ratio of the potential of the second node N2 in each stage is surely reduced as compared with the prior art. Thereby, by reliably suppressing threshold value fluctuations of the thin film transistors M5 and M6, it is possible to reliably improve their reliability.
- the power consumption W required to drive the capacitive load is proportional to the product of the square of the voltage (amplitude) V, the capacitance value C, and the frequency f.
- the capacitance value C increases as the number of thin film transistors to which a clock signal is applied to the gate terminal increases. That is, in the gate driver, the consumption electrode W increases as the number of thin film transistors to which the clock signal is applied to the gate terminal increases.
- the clock signal is supplied to the gate terminal directly or through another transistor.
- the clock signal CK1 four transistors T4, T5, T9, and T11 and the clock signal CK2 are used. Are three transistors T6, T8, and T10.
- a transistor to which a clock signal is applied to the gate terminal directly or via another transistor is one transistor T4 for the operation control clock signal CKA and one for the charge replenishment clock signal CKB.
- the drive frequency in the writing period is increased (the writing period is shortened) in accordance with the length of the vertical blanking period, that is, the frequency of the pre-control gate clock signal GCKf. Therefore, the length of one vertical scanning period is not different from the conventional one. As a result, the reliability of the thin film transistors M5 and M6 can be improved without reducing the substantial driving frequency.
- the clock control circuit 420 is configured to perform the pre-control gate clock signal GCKf (the pre-control first gate clock signal GCKf1 and the pre-control second) based on the gate start pulse signal GSP and the gate end pulse signal GEP.
- the supply of the gate clock signal GCKf2) to the bistable circuit is controlled. For this reason, the supply control of the pre-control gate clock signal GCKf is reliably performed. Thereby, the circuit operation can be stabilized.
- the potential of the second node N2 in each stage is surely at a low level at the start in the vertical blanking period. This reliably reduces the duty ratio of the potential applied to the gate terminal of the thin film transistor M5 and the gate terminal of the thin film transistor M6, and stabilizes the circuit operation.
- the thin film transistor MA since the thin film transistor MA is provided in each stage, the potential of the first node N1 in each stage is surely at a low level at the start of the vertical blanking period. Thereby, the duty ratio of the potential applied to the gate terminal of the thin film transistor M5 and the gate terminal of the thin film transistor M6 is more reliably reduced, and the circuit operation is further stabilized.
- the thin film transistor M4 since the thin film transistor M4 is provided, the potential of the second node N2 is surely at a low level in the selection period. Thereby, the circuit operation is further stabilized.
- FIG. 17 is a circuit diagram showing a configuration of a bistable circuit other than the first stage (frontmost stage) and the mth stage (last stage) in the first modification of the first embodiment.
- FIG. 18 is a circuit diagram showing a configuration of a first stage (frontmost stage) bistable circuit in the present modification.
- the thin film transistor MA is provided at each stage.
- the first stage 40 (1) to the m ⁇ 1th stage 40 (m In 1) the thin film transistor MA is not provided.
- the first stage 40 (1) to the m ⁇ 1th stage 40 m In 1
- the potentials of the first-stage first node N1 (1) to the (m-1) -th stage first node N1 (m-1) are at the low level. Even in a mode in which the thin film transistor MA is not provided in the first stage 40 (1) to the (m ⁇ 1) th stage 40 (m ⁇ 1), the first stage first node N1 (1) to the (m ⁇ 1) th stage in the vertical blanking period. The potential of the first node N1 (m ⁇ 1) can be set to a low level.
- the thin film transistor MA is provided in the m-th stage 40 (m) in the present modification, as in the first embodiment. According to this modification, since the number of thin film transistors is reduced, the power consumption can be further reduced, and the frame area of the liquid crystal display device including the gate driver 400 can be further reduced.
- FIG. 19 is a signal waveform diagram for explaining the detailed operation of the gate driver 400 in the second modification of the first embodiment.
- one vertical scanning period is driven at a driving frequency of 60 Hz (about 16.7 msec).
- the driving frequency of the writing period is 60 Hz (about 16.7 msec)
- the length of the vertical blanking period is about 16.7 msec, which is about 1 ⁇ 2 of the length of the vertical scanning period.
- the duty ratio of the potential of the second node N2 in each stage is substantially 1 ⁇ 2, the same effect as in the first embodiment can be obtained.
- the length of the vertical blanking period is about 25 msec, which is about 3/4 of the length of the vertical scanning period.
- the duty ratio of the potential of the second node N2 at each stage is substantially 1 ⁇ 4. Therefore, threshold value fluctuations of the thin film transistors M5 and M6 are further suppressed.
- FIG. 20 is a signal waveform diagram for explaining the detailed operation of the gate driver 400 in the third modification of the first embodiment.
- one vertical scanning period is driven at a driving frequency of 60 Hz (about 16.7 msec).
- the driving frequency of the writing period is 60 Hz (about 16.7 msec) as in the second modification
- the length of the vertical blanking period is about 3/4 of the length of the vertical scanning period. It is about 50 msec.
- the duty ratio of the potential of the second node N2 at each stage is substantially 1 ⁇ 4. Therefore, threshold value fluctuations of the thin film transistors M5 and M6 are suppressed as compared with the first embodiment.
- the length of the vertical blanking period is about 58.3 msec, which is about 7/8 of the length of the vertical scanning period. .
- the duty ratio of the potential of the second node N2 in each stage is substantially 1/8. Therefore, threshold value fluctuations of the thin film transistors M5 and M6 are further suppressed.
- FIG. 21 is a circuit diagram showing a configuration of a bistable circuit other than the first stage (frontmost stage) and the mth stage (last stage) in the fourth modification example of the first embodiment.
- the thin film transistors M3 and M4 are provided at each stage.
- a thin film transistor M10 is provided instead of the thin film transistors M3 and M4. Since the same applies to the first stage (frontmost stage) and the mth stage (last stage), the description and illustration thereof are omitted.
- the thin film transistor M10 has a gate terminal connected to the first node N1, a drain terminal connected to the second node, and a source terminal connected to the input terminal for the DC power supply potential Vss.
- the thin film transistor M10 changes the potential of the second node N2 toward the Vss potential when the potential of the first node N1 is at a high level.
- a second node turn-off switching element is realized by the thin film transistor M10. According to this modification, by providing the thin film transistor M10 in each bistable circuit instead of the thin film transistors M3 and M4, the potential of the second node N2 can be reliably maintained at a low level in the set period and the selection period.
- FIG. 22 is a signal waveform diagram for explaining the detailed operation of the gate driver 400 according to the second embodiment of the present invention. Note that the overall configuration and operation of the liquid crystal display device, the configuration of the gate driver 400, the configuration and operation of the bistable circuit, and the configuration and operation of the clock control circuit 420 are the same as those in the first embodiment. Since these are the same as those described above, their description is omitted.
- a vertical blanking period (about 8.3 msec) that is about 1 ⁇ 2 the length of one vertical scanning period is provided, and the driving frequency of the writing period is set to a general driving frequency (60 Hz). 120 Hz (about 8.3 msec).
- a vertical blanking period (about 11.1 msec) having a length of about 2/3 of one vertical scanning period is provided, and the driving frequency of the writing period is set. , 180 Hz (about 5.6 msec), which is three times the general driving frequency. That is, in this embodiment, the length of the vertical blanking period is about twice the length of the writing period. Note that the operations in the writing period and the vertical blanking period in the present embodiment are the same as those in the first embodiment, and a description thereof will be omitted.
- the potential of the second node N2 in each stage is at a high level in the writing period excluding the set period and the selection period in the stage, and the set period, the selection period, and the pause period in the stage are set. It becomes low level in the vertical blanking period including.
- the length of the vertical blanking period is about twice the length of the writing period.
- the duty ratio of the potential of the second node N2 in each stage is substantially 1/3. That is, the duty ratio of the potential applied to the gate terminal of the thin film transistor M5 and the gate terminal of the thin film transistor M6 is substantially 3.
- threshold value fluctuations of the thin film transistors M5 and M6 are further suppressed as compared with the first embodiment. For this reason, since the reliability of the thin film transistors M5 and M6 is further increased, the size of the thin film transistor can be further reduced. Thus, when the sizes of the thin film transistors M5 and M6 are reduced, the power consumption can be further reduced and the frame area of the liquid crystal display device including the gate driver 400 can be further reduced.
- FIG. 23 is a signal waveform diagram for describing a detailed operation of the gate driver 400 in the third embodiment of the present invention. Note that the overall configuration and operation of the liquid crystal display device, the configuration of the gate driver 400, the configuration and operation of the bistable circuit, and the configuration and operation of the clock control circuit 420 are the same as those in the first embodiment. Since these are the same as those described above, their description is omitted.
- a vertical blanking period (about 8.3 msec) that is about 1 ⁇ 2 the length of one vertical scanning period is provided, and the driving frequency of the writing period is set to a general driving frequency (60 Hz). 120 Hz (about 8.3 msec).
- a vertical blanking period (about 11.1 msec) having a length of about 2/3 of one vertical scanning period is provided, and the driving frequency of the writing period is set to a general driving frequency.
- the triple speed is 180 Hz (about 5.6 msec).
- a vertical blanking period (about 12.5 msec) having a length of about 3/4 of one vertical scanning period is provided, and the driving frequency of the writing period is set to a general driving frequency.
- the quadruple speed is 240 Hz (about 4.2 msec). That is, in this embodiment, the length of the vertical blanking period is about three times the length of the writing period. Note that the operations in the writing period and the vertical blanking period in the present embodiment are the same as those in the first embodiment, and a description thereof will be omitted.
- the potential of the second node N2 in each stage is at a high level in the writing period excluding the set period and the selection period in the stage, and the set period in the stage. And the low level during the selection period and the vertical blanking period including the pause period.
- the length of the vertical blanking period is about three times the length of the writing period.
- the duty ratio of the potential of the second node N2 in each stage is substantially 1 ⁇ 4. That is, the duty ratio of the potential applied to the gate terminal of the thin film transistor M5 and the gate terminal of the thin film transistor M6 is substantially 1 ⁇ 4.
- threshold value fluctuations of the thin film transistors M5 and M6 are further suppressed as compared with the second embodiment. For this reason, since the reliability of the thin film transistor is further increased, the size of the thin film transistor can be further reduced. As a result, power consumption can be further reduced, and the frame area of the liquid crystal display device including the gate driver 400 can be further reduced.
- FIG. 24 is a signal waveform diagram for describing a detailed operation of the gate driver 400 according to the fourth embodiment of the present invention. Note that the overall configuration and operation of the liquid crystal display device, the configuration of the gate driver 400, the configuration and operation of the bistable circuit, and the configuration and operation of the clock control circuit 420 are the same as those in the first embodiment. Since these are the same as those described above, their description is omitted.
- a vertical blanking period (about 8.3 msec) that is about 1 ⁇ 2 the length of one vertical scanning period is provided, and the driving frequency of the writing period is set to a general driving frequency (60 Hz). 120 Hz (about 8.3 msec).
- a vertical blanking period (about 5.6 msec) having a length of about 1/3 of one vertical scanning period is provided, and the driving frequency of the writing period is set.
- 90 Hz (about 11.1 msec), which is 1.5 times the general driving frequency. That is, in the present embodiment, the length of the vertical blanking period is about 1 ⁇ 2 times the length of the writing period.
- the operations in the writing period and the vertical blanking period in the present embodiment are the same as those in the first embodiment, and a description thereof will be omitted.
- the potential of the second node N2 in each stage is at a high level in the writing period excluding the set period and the selection period in the stage, and the set period, the selection period, and the pause period in the stage are set. It becomes low level in the vertical blanking period including.
- the length of the vertical blanking period is about 1 ⁇ 2 times the length of the writing period.
- the duty ratio of the potential of the second node N2 in each stage is substantially 2/3. That is, the duty ratio of the potential applied to the gate terminal of the thin film transistor M5 and the gate terminal of the thin film transistor M6 is substantially 2/3.
- the driving frequency in the writing period in the present embodiment is lower than that in the first embodiment.
- the power consumption is further reduced and the circuit operation is further stabilized. Therefore, according to the present embodiment, it is possible to further improve the reliability of the thin film transistor as compared with the related art while further reducing the power consumption and further stabilizing the circuit operation.
- FIG. 25 shows the start time of the first vertical scanning period after power-on in the gate driver 400 according to the fifth embodiment of the present invention (the time when the gate start pulse signal GSP first changes from low level to high level). It is a signal waveform diagram for demonstrating the operation
- the overall configuration and operation of the liquid crystal display device, the configuration of the gate driver 400 and the operation other than immediately after power-on, the configuration and operation of the bistable circuit, and the configuration and operation of the clock control circuit 420 are described in this embodiment. Since these are the same as those in the first embodiment, description thereof will be omitted.
- the first input of the second control signal generation circuit 72 shown in FIG. 13 becomes low level
- the second input becomes low level
- the second control signal CT2 which is the output of the second control signal generation circuit 72 is obtained.
- the post-control first gate clock signal GCK1 and the post-control second gate clock signal GCK2 become low level. That is, at this time, the supply of the pre-control gate clock signal GCKf to each bistable circuit is stopped. This state is maintained until the gate start pulse signal GSP changes from the high level to the low level in the writing period of the first vertical scanning period.
- the thin film transistors MA and MB are turned on at each stage that receives the gate end pulse signal GEP as the end signal ED.
- the potentials of the first-stage first node N1 (1) to the m-th stage first node N1 (m) are reset to a low level and the first-stage second node N2 (1) to the m-th stage first node.
- the potential of the two node N2 (m) is reset to a low level.
- the potential of the first node N1 and the potential of the second node N2 that are unstable in the period from when the power is turned on to the start of the first vertical scanning period are reset to a low level. Further, during the period from when the power is turned on to the start of the first vertical scanning period, the supply of the pre-control gate clock signal GCKf to each bistable circuit is stopped. For this reason, the potential of the first node N1 and the potential of the second node N2 are reliably maintained at a low level. Thereby, the circuit operation can be further stabilized.
- FIG. 26 is a block diagram showing a configuration other than the foremost stage and the last stage of the shift register 410 according to the sixth embodiment of the present invention.
- FIG. 27 is a block diagram showing a configuration on the forefront side of the shift register 410 in the present embodiment.
- FIG. 28 is a block diagram showing a configuration on the last stage side of the shift register 410 in the present embodiment. Note that the overall configuration and operation of the liquid crystal display device and the configuration and operation of the clock control circuit 420 are the same as those in the first embodiment, and thus the description thereof is omitted.
- each bistable circuit in this embodiment is provided with an input terminal for receiving the charge replenishment clock signal CKB, unlike each bistable circuit in the first embodiment.
- the first gate clock signal GCK1 after control is supplied as the operation control clock signal CKA
- the second gate clock signal GCK2 after control is supplied as the operation control clock signal CKA.
- the other terminals (input terminal and output terminal) of each bistable circuit in the present embodiment are the same as those in each bistable circuit of the first embodiment.
- the basic operation of the gate driver 400 in the present embodiment is the same as that of the gate driver 400 in the first embodiment, and a description thereof will be omitted.
- FIG. 29 is a circuit diagram showing a configuration of a bistable circuit other than the first stage (frontmost stage) and the mth stage (last stage) in the present embodiment.
- this bistable circuit is obtained by adding thin film transistors M8, MA, and MB to the bistable circuit described in Patent Document 1 (FIG. 32).
- the bistable circuit in this embodiment is not provided with the thin film transistors M4 and M9.
- This bistable circuit is provided with five input terminals 41 to 44 and 46 and one output terminal 51 in addition to the input terminal for the low-level DC power supply potential Vss. As described above, this bistable circuit is not provided with the input terminal 47 for receiving the charge replenishment clock signal CKB.
- the first driving unit 61 is composed of three thin film transistors M1, M5, and MA, as in the first embodiment.
- the second drive unit 62 includes four thin film transistors M3, M4, M8, M9, and MB, and one capacitor C2.
- the output unit 63 includes two thin film transistors M2 and M6 and one capacitor C1 as in the first embodiment.
- the source terminal of the thin film transistor M1, the drain terminal of the thin film transistor M5, and the drain terminal of the thin film transistor MA provided in the first drive unit 61 are connected to the first node N1.
- the drain terminal of the thin film transistor M3, the source terminal of the thin film transistor M7, the source terminal of the thin film transistor M8, the drain terminal of the thin film transistor MB, and one end of the capacitor C2 provided in the second driver 62 are connected to the second node N2.
- a gate terminal of the thin film transistor M2 provided in the output unit 63 and one end of the capacitor C1 are connected to the first node N1, and a gate terminal of the thin film transistor M6 is connected to the second node N2. Since the connection and function of each thin film transistor and each capacitor are the same as those in the first embodiment, the description thereof is omitted.
- FIG. 30 is a circuit diagram showing a configuration of a first stage (frontmost stage) bistable circuit in the present embodiment. As shown in FIG. 30, this bistable circuit is provided with a thin film transistor M8 and an input terminal 44, unlike the bistable circuit other than the first stage (frontmost stage) and the mth stage (last stage) shown in FIG. Not. Other configurations of the bistable circuit are the same as those of the bistable circuit other than the first stage (frontmost stage) and the mth stage (last stage) shown in FIG.
- FIG. 31 is a circuit diagram showing a configuration of the m-th (last stage) bistable circuit in the present embodiment. As shown in FIG. 31, this bistable circuit is provided with a thin film transistor M7 and an input terminal 42, unlike the bistable circuit other than the first stage (frontmost stage) and the mth stage (last stage) shown in FIG. Not. Other configurations of the bistable circuit are the same as those of the bistable circuit other than the first stage (frontmost stage) and the mth stage (last stage) shown in FIG.
- the first node turn-on switching element is realized by the thin film transistor M1
- the output control switching element is realized by the thin film transistor M2
- the first second switch is realized by the thin film transistor M3.
- a node turn-off switching element is realized, a thin-film transistor M5 realizes a first node turn-off switching element, a thin-film transistor M6 realizes an output node turn-off switching element, and a thin-film transistor M7 realizes a second node turn-off switching element.
- a thin film transistor M8 realizes a start switching element, and a thin film transistor MA realizes a first end switching element.
- the second end switching element is realized by.
- a capacitor element is realized by the capacitor C1.
- bistable circuit ⁇ 6.3 Operation of bistable circuit>
- the basic operation of the bistable circuit in this embodiment is the same as that in the first embodiment. Therefore, description of operations common to the present embodiment and the first embodiment will be omitted, and only differences from each other will be described with reference to FIG.
- the potential of the charge supplement clock signal CKB changes between the high level and the low level every horizontal period.
- the thin film transistor M9 is turned on in one horizontal period every two horizontal scanning periods. For this reason, charges are supplied to the second node N2 via the thin film transistor M9. This ensures that the potential of the second node N2 is maintained at a high level during the normal operation period.
- the input terminal 47 and the thin film transistor M9 for receiving the charge replenishment clock signal CKB are not provided. Therefore, as in the first embodiment, the second node in the normal operation period. No charge is supplied to N2. Therefore, the present embodiment is not different from the conventional one in terms of the stability of the potential of the second node N2 during the normal operation period.
- the present embodiment since the thin film transistor M4 is not provided, an operation for surely setting the potential of the second node N2 to the low level during such a selection period is not performed. Therefore, the present embodiment is not different from the conventional one regarding the potential of the second node N2 in the selection period.
- the detailed operation of the gate driver in the present embodiment is the same as that in the first embodiment, except that the potential of the second node N2 is likely to be unstable during the normal operation period and the selection period. Therefore, explanation is omitted.
- the potential of the second node N2 in the normal operation period and the selection period becomes more unstable than in the first embodiment, so that the potential of the first node N1 and the state signal Q (scanning signal) ) Is likely to generate noise. That is, in this embodiment, circuit operation tends to become unstable.
- the threshold fluctuations of the thin film transistors M5 and M6 are suppressed more than before, and the number of thin film transistors to which a clock signal is applied to the source terminal becomes smaller than before.
- the reliability of the thin film transistors M5 and M6 can be increased while reducing power consumption.
- the reliability of the thin film transistors M5 and M6 is increased, so that the sizes of the thin film transistors M5 and M6 can be reduced.
- the power consumption is further reduced and the frame area of the liquid crystal display device including the gate driver 400 can be reduced.
- the thin film transistor MA may not be provided in the first stage 40 (1) to the m ⁇ 1th stage 40 (m ⁇ 1). In this case, since the number of thin film transistors is further reduced, power consumption can be further reduced and the frame area of the liquid crystal display device including the gate driver 400 can be further reduced.
- the configuration of the gate driver 400 in the present invention is not limited to that in the above embodiments. That is, the gate driver 400 includes at least thin film transistors M5 and M6 in each bistable circuit, and provides a vertical blanking period longer than two horizontal scanning periods, and a clock signal to each bistable circuit in this vertical blanking period. And the potential of the first node connected to the drain terminal of the thin film transistor M5 and the potential of the second node N2 connected to the gate terminals of the thin film transistors M5 and M6 during the vertical blanking period As long as the configuration is maintained at the off level.
- the thin film transistors M8, MA, and MB in the first embodiment may be added.
- the transistors T4 and T5 correspond to the thin film transistors M5 and M6 in the present invention.
- the first drive unit 61 is realized by the input unit 920
- the second drive unit 62 is realized by the pull-down drive unit 940
- the output unit 63 is realized by the output unit 450.
- the gate terminals of the transistors T4 and T5 to which the second node N2 is connected are connected. In other words, a potential having a duty ratio substantially 1 ⁇ 4 is applied.
- the threshold fluctuation occurring in the transistors T4 and T5 can be suppressed as compared with the second conventional example.
- the potential of the second node N2 has a duty ratio of 1/2 in the writing period (the length of the writing period and the length of the vertical blanking period are the same as those in the first embodiment. Therefore, the noise resulting from the potential fluctuation of the second node N2 is generated in the potential of the first node N2 and the potential of the state signal Q. Therefore, the stability of the circuit operation is inferior to that of the first embodiment.
- the supply of the clock signal to each bistable circuit is stopped in the vertical blanking period, but the present invention is not limited to this. Even if the supply of the clock signal to each bistable circuit is not stopped in the vertical blanking period, the threshold value fluctuations of the transistors M5 and M6 can be suppressed more than in the past.
- the length of the vertical blanking period is about 1/2, about 2/3, about 3/4, and about 1/3 of the length of one vertical scanning period, respectively.
- the length of the vertical blanking period is sufficiently long from the viewpoint of improving the reliability of the thin film transistor.
- the clock control circuit 420 controls the supply of the clock signal to the bistable circuit, but the present invention is not limited to this.
- the display control circuit 200 directly generates clock signals corresponding to the above-described controlled first gate clock signal GCK1 and the controlled second gate clock signal GCK2. However, it may be supplied to a bistable circuit.
- the clock control circuit 420 in each of the above embodiments controls the supply of the pre-control gate clock signal GCKf based on the gate start pulse signal GSP and the gate end pulse signal GEP, but the present invention is not limited to this. is not.
- a gate end pulse signal GEP delayed by the length of the vertical blanking period is used instead of the gate start pulse signal GSP.
- the second control signal generation circuit 72 may be provided.
- the configuration of the clock control circuit 420 is not particularly limited.
- one clock control circuit 420 is provided in the gate driver 400, but the present invention is not limited to this.
- a circuit corresponding to the clock control circuit 420 may be provided in each bistable circuit.
- the thin film transistors provided in the bistable circuit are all n-channel type, but the present invention is not limited to this. The present invention can be applied even if the thin film transistor provided in the bistable circuit is a p-channel type.
- the liquid crystal display device has been described as an example, but the present invention is not limited to this.
- the present invention can also be applied to other display devices such as organic EL (Electro Luminescence) display devices.
- organic EL Electro Luminescence
- the above-described embodiments can be variously modified and implemented without departing from the spirit of the present invention.
- a scanning signal line driving circuit that reduces the power consumption and increases the reliability of the switching element, a display device including the scanning signal line driving circuit, and a scanning signal line driving method.
- the present invention can be applied to a scanning signal line driving circuit, a display device including the scanning signal line driving method, and a scanning signal line driving method using the scanning signal line driving circuit, in particular, a monolithic scanning signal line driving circuit, It is suitable for a display device provided with the display device and a scanning signal line driving method using the scanning signal line driving circuit.
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Abstract
Description
互いに縦続接続された複数の双安定回路を含み、外部から入力されオンレベルとオフレベルとを周期的に繰り返すクロック信号に基づいて前記複数の双安定回路の出力信号を順次にアクティブとするシフトレジスタを備え、
各双安定回路は、
第1ノードに接続され、受け取った信号に基づいて該第1ノードの電位を変化させる第1駆動部と、
第2ノードに接続され、受け取った信号に基づいて該第2ノードの電位を変化させる第2駆動部と、
前記第1ノードおよび前記第2ノードに接続され、該第1ノードの電位および該第2ノード電位がそれぞれオンレベルおよびオフレベルであり、かつ、該第1駆動部が受け取った信号の電位がオフレベルであるときに、アクティブな前記出力信号を前記クロック信号に基づいて出力する出力部とを有し、
前記第1駆動部は、前記第2ノードが制御端子に接続され、前記第1ノードが一方の導通端子に接続され、オフレベルの電位が他方の導通端子に与えられた第1ノードターンオフ用スイッチング素子を有し、
前記出力部は、前記第2ノードが制御端子に接続され、前記出力信号を出力するための出力ノードが一方の導通端子に接続され、オフレベルの電位が他方の導通端子に与えられた出力ノードターンオフ用スイッチング素子を有し、
前記第1駆動部および前記第2駆動部が、各垂直走査期間のうちの2水平走査期間以上の所定期間において前記第1ノードの電位および前記第2ノードの電位をそれぞれオフレベルに維持することを特徴とする。
前記所定期間において、前記複数の双安定回路への前記クロック信号の供給が停止することを特徴とする。
前記所定期間が長いほど、前記クロック信号の周波数が高くなることを特徴とする。
前記第1駆動部および第2駆動部は、電源投入後から最初の垂直走査期間の開始までの間にさらに、前記第1ノードの電位および前記第2ノードの電位をそれぞれオフレベルに維持し、
電源投入後から最初の垂直走査期間の開始までの間にさらに、前記複数の双安定回路への前記クロック信号の供給が停止することを特徴とする。
前記シフトレジスタにおける最終段の双安定回路の出力信号がアクティブとなった後に該出力信号を非アクティブとするために電位がオンレベルとなるエンド信号に基づいて、前記所定期間において、前記複数の双安定回路への前記クロック信号の供給を停止させるクロック制御回路をさらに備えることを特徴とする。
最終段の双安定回路における第1駆動部は、前記エンド信号が制御端子に与えられ、前記第1ノードが一方の導通端子に接続され、オフレベルの電位が他方の導通端子に与えられた第1エンド用スイッチング素子をさらに有し、
各双安定回路における前記第2駆動部は、前記エンド信号が制御端子に与えられ、前記第2ノードが一方の導通端子に接続され、オフレベルの電位が他方の導通端子に与えられた第2エンド用スイッチング素子を有することを特徴とする。
最終段以外の各段の双安定回路における第1駆動部は、前記第1エンド用スイッチング素子をさらに有することを特徴とする。
最前段以外の各段の双安定回路における第2駆動部は、各垂直走査期間の開始のタイミングでオンレベルとなるスタート信号に基づいて、前記第2ノードの電位をオンレベルに向けて変化させるスタート用スイッチング素子をさらに有することを特徴とする。
前記第1駆動部は、セット信号に基づいて、前記第1ノードの電位をオンレベルに向けて変化させる第1ノードターンオン用スイッチング素子をさらに有し、
最前段の双安定回路における前記セット信号は、前記スタート信号であり、
最前段以外の双安定回路における前記セット信号は、該双安定回路の前段の双安定回路の出力信号であることを特徴とする。
前記出力部は、
前記第1ノードが導通端子に接続され、前記クロック信号が一方の導通端子に与えられ、前記出力ノードが他方の導通端子に接続された出力制御用スイッチング素子と、
前記出力制御用スイッチング素子の制御端子が一端に接続され、前記出力ノードが他端に接続された容量素子とをさらに有することを特徴とする。
前記第2駆動部は、前記第2ノードが一方の導通端子に接続され、オフレベルの電位が他方の導通端子に与えられた第2ノードターンオフ用スイッチング素子をさらに有することを特徴とする。
前記第2駆動部には、前記第2ノードターンオフ用スイッチング素子として、
前記セット信号が制御端子に与えられ、前記第2ノードが一方の導通端子に接続され、オフレベルの電位が他方の導通端子に与えられた第1の第2ノードターンオフ用スイッチング素子と、
前記出力ノードが制御端子に接続され、前記第2ノードが一方の導通端子に接続され、オフレベルの電位が他方の導通端子に与えられた第2の第2ノードターンオフ用スイッチング素子とが設けられていることを特徴とする。
前記第2ノードターンオフ用スイッチング素子の制御端子が、前記第1ノードに接続されていることを特徴とする。
最前段以外の各段の双安定回路における第2駆動部は、該双安定回路の後段の双安定回路の出力信号に基づいて、前記第2ノードの電位をオンレベルに向けて変化させる第2ノードターンオン用スイッチング素子をさらに有することを特徴とする。
前記クロック信号は、互いに1水平走査期間だけ位相がずれた第1クロック信号および第2クロック信号からなり、
前記出力制御用スイッチング素子の一方の導通端子には前記第1クロック信号が与えられ、
前記第2駆動部は、前記第2クロック信号に基づいて前記第2ノードの電位をオンレベルに向けて変化させる電荷補充用スイッチング素子をさらに有することを特徴とする。
複数の走査信号線が配置された表示部と、
前記複数の走査信号線を駆動する走査信号線駆動回路と
前記走査信号線駆動回路に、オンレベルとオフレベルとを周期的に繰り返すクロック信号を供給する表示制御回路とを備え、
前記走査信号線駆動回路は、互いに縦続接続された複数の双安定回路を有し、前記クロック信号に基づいて前記複数の双安定回路の出力信号を順次にアクティブとするシフトレジスタを含み、
各双安定回路は、
第1ノードに接続され、受け取った信号に基づいて該第1ノードの電位を変化させる第1駆動部と、
第2ノードに接続され、受け取った信号に基づいて該第2ノードの電位を変化させる第2駆動部と、
前記第1ノードおよび前記第2ノードに接続され、該第1ノードの電位および該第2ノード電位がそれぞれオンレベルおよびオフレベルであり、かつ、該第1駆動部が受け取った信号の電位がオフレベルであるときに、アクティブな前記出力信号を前記クロック信号に基づいて出力する出力部とを有し、
前記第1駆動部は、前記第2ノードが制御端子に接続され、前記第1ノードが一方の導通端子に接続され、オフレベルの電位が他方の導通端子に与えられた第1ノードターンオフ用スイッチング素子を有し、
前記出力部は、前記第2ノードが制御端子に接続され、前記出力信号を出力するための出力ノードが一方の導通端子に接続され、オフレベルの電位が他方の導通端子に与えられた出力ノードターンオフ用スイッチング素子を有し、
前記第1駆動部および前記第2駆動部が、各垂直走査期間のうちの2水平走査期間以上の所定期間において前記第1ノードの電位および前記第2ノードの電位をそれぞれオフレベルに維持することを特徴とする。
前記所定期間において、前記複数の双安定回路への前記クロック信号の供給が停止することを特徴とする。
前記走査信号線駆動回路は、前記シフトレジスタにおける最終段の双安定回路の出力信号がアクティブとなった後に該出力信号を非アクティブとするために電位がオンレベルとなるエンド信号に基づいて、前記所定期間において、前記複数の双安定回路への前記クロック信号の供給を停止させるクロック制御回路をさらに含むことを特徴とする。
前記表示制御回路は、前記所定期間において、前記複数の双安定回路への前記クロック信号の供給を停止することを特徴とする。
前記表示制御回路が、前記所定期間が長いほど、前記クロック信号の周波数を高めることを特徴とする。
前記表示部と前記走査信号線駆動回路とが一体的に形成されていることを特徴とする。
各双安定回路において信号を受け取り、該信号に基づいて、該双安定回路における第1ノードの電位を変化させるステップと、
各双安定回路において信号を受け取り、該信号に基づいて、該双安定回路における第2ノードの電位を変化させるステップと、
前記第1ノードの電位および前記第2ノードの電位がそれぞれオンレベルおよびオフレベルであり、かつ、前記第1ノードの電位を変化させるステップにおいて各双安定回路が受け取った信号の電位がオフレベルであるときに、アクティブな前記出力信号を出力するステップとを備え、
各双安定回路は、
前記第2ノードが制御端子に接続され、前記第1ノードが一方の導通端子に接続され、オフレベルの電位が他方の導通端子に与えられた第1ノードターンオフ用スイッチング素子と、
前記第2ノードが制御端子に接続され、前記出力信号を出力するための出力ノードが一方の導通端子に接続され、オフレベルの電位が他方の導通端子に与えられた出力ノードターンオフ用スイッチング素子を有し、
前記第1ノードの電位を変化させるステップでは、各垂直走査期間のうちの2水平走査期間以上の所定期間において前記第1ノードの電位がオフレベルに維持され、
前記第2ノードの電位を変化させるステップでは、前記所定期間において前記第2ノードの電位がオフレベルに維持されることを特徴とする。
前記所定期間において、前記複数の双安定回路への前記クロック信号の供給を停止するステップをさらに備えることを特徴とする。
前記所定期間が長いほど、前記クロック信号の周波数が高くなることを特徴とする。
前記第1ノードの電位を変化させるステップでは、電源投入後から最初の垂直走査期間の開始までの間にさらに、前記第1ノードの電位がオフレベルに維持され、
前記第2ノードの電位を変化させるステップでは、電源投入後から最初の垂直走査期間の開始までの間にさらに、前記第2ノードの電位がオフレベルに維持され、
前記クロック信号の供給を停止するステップでは、電源投入後から最初の垂直走査期間の開始までの間にさらに、前記クロック信号の供給が停止されることを特徴とする。
<1.1 全体構成および動作>
図1は、本発明の第1の実施形態に係るアクティブマトリクス型の液晶表示装置の全体構成を示すブロック図である。図1に示すように、この液晶表示装置は、電源100とDC/DCコンバータ110と表示制御回路200とソースドライバ(映像信号線駆動回路)300とゲートドライバ(走査信号線駆動回路)400と共通電極駆動回路500と表示部600とを備えている。なお、ゲートドライバ400は、アモルファスシリコン、多結晶シリコン、微結晶シリコン、または酸化物半導体(例えばIGZO)などを用いて、表示部600を含む表示パネル上に形成されている。すなわち、本実施形態においては、ゲートドライバ400と表示部600とは同一基板(液晶パネルを構成する2枚の基板のうちの一方の基板であるアレイ基板)上に形成されている。これにより、液晶表示装置の額縁面積を縮小することができる。
図2は、本実施形態におけるゲートドライバ400の構成を説明するためのブロック図である。図2に示すように、ゲートドライバ400はm個(段)の双安定回路40(1)~40(m)からなるシフトレジスタ410およびクロック制御回路420によって構成されている。クロック制御回路420は、上述のゲートスタートパルス信号GSP、ゲートエンドパルス信号GEP、および制御前ゲートクロック信号GCKfを受け取り、当該制御前ゲートクロック信号GCKfを一部の期間停止させた信号であるゲートクロック信号GCK(以下「制御後ゲートクロック信号」という)をシフトレジスタ410に供給する。なお、このクロック制御回路420の詳しい説明については後述する。
図7は、本実施形態における、1段目(最前段)およびm段目(最後段)以外の双安定回路の構成を示す回路図である。図7に示すように、この双安定回路は、第1駆動部61、第2駆動部62、および出力部63により構成されている。また、この双安定回路には、ローレベルの直流電源電位Vss用の入力端子のほか、6個の入力端子41~44、46および47と1個の出力端子(出力ノード)51とが設けられている。ここで、セット信号Sを受け取る入力端子には符号41を付し、リセット信号Rを受け取る入力端子には符号42を付し、エンド信号EDを受け取る入力端子には符号43を付し、スタート信号STを受け取る入力端子には符号44を付し、動作制御用クロック信号CKAを受け取る入力端子には符号46を付し、電荷補充用クロック信号CKBを受け取る入力端子には符号47を付している。また、状態信号Qを出力する出力端子には符号51を付している。
図10は、本実施形態におけるi段目の双安定回路40(i)の動作を説明するための信号波形図である。なお、他の双安定回路も同様の動作であるので、説明を省略する。図10では、時点t1から時点t2までの期間が選択期間に相当する。以下では、選択期間直前の1水平走査期間のことを「セット期間」といい、選択期間直後の1水平走査期間のことを「リセット期間」という。また、1垂直走査期間のうち、スタート信号ST(ゲートスタートパルス信号GSP)が立ち上がる時点からエンド信号ED(ゲートエンドパルス信号GEP)が立ち上がる時点までの期間を「書き込み期間」という。また、1垂直走査期間のうち、エンド信号EDが立ち上がる時点から後続の垂直走査期間においてスタート信号STが立ち上がる時点までの期間(所定期間)を「垂直帰線期間」という。なお、この垂直帰線期間のうち、エンド信号EDがローレベルとなっている期間を特に「休止期間」という。また、書き込み期間のうちの、選択期間、セット期間、およびリセット期間以外の期間のことを「通常動作期間」という。
図11は、本実施形態におけるクロック制御回路420の構成を示すブロック図である。このクロック制御回路420は、上述のようにゲートドライバ400内に設けられている。図11に示すように、このクロック制御回路420は、第1制御信号生成回路71、第2制御信号生成回路72、およびクロック出力回路73により構成されている。
図15は、本実施形態におけるクロック制御回路420の動作を説明するための信号波形図である。図15に示すように、制御前第1ゲートクロック信号GCK1fおよび制御前第2ゲートクロック信号GCKf2は、ハイレベルとローレベルとを周期的に繰り返している。
図16は、本実施形態におけるゲートドライバ400の詳細な動作を説明するための信号波形図である。本実施形態および後述の各実施形態では、1垂直走査期間を、一般的な駆動周波数である60Hz(約16.7msec)で駆動するものとして説明する。図16に示すように、本実施形態では、1垂直走査期間の約1/2の長さの垂直帰線期間(約8.3msec)を設けている。これに合わせて、書き込み期間の駆動周波数を、一般的な駆動周波数の倍速の120Hz(約8.3msec)している。すなわち、本実施形態では、書き込み期間の長さと垂直帰線期間の長さとが互いにほぼ等しくなっている。なお、以下では、説明の便宜上、1段目40(1)~m段目40(m)における第1ノードN1をそれぞれ符号N1(1)~N1(m)で表し、第2ノードN2をそれぞれ符号N2(1)~N2(m)で表す。また、第1ノードN1(1)~N1(m)をそれぞれ「1段目第1ノード~m段目第1ノード」といい、第2ノードN2(1)~N2(m)をそれぞれ「1段目第2ノード~m段目第2ノード」という。
本実施形態では、以上のような動作により、各段における第2ノードN2の電位が、当該段のセット期間および選択期間を除く書き込み期間においてハイレベルとなると共に、当該段のセット期間と、選択期間と、上記休止期間を含む垂直帰線期間とにおいてローレベルとなる。また、垂直帰線期間の長さが、1垂直走査期間の約1/2となっている。このため、各段における第2ノードN2の電位のデューティー比が実質的に1/2となる。すなわち、薄膜トランジスタM5のゲート端子および薄膜トランジスタM6のゲート端子に与えられる電位のデューティー比が実質的に1/2となる。これにより、これらの薄膜トランジスタM5およびM6のしきい値変動が抑制される。したがって、本実施形態によれば、薄膜トランジスタM5およびM6の信頼性を高めることができる。これらの薄膜トランジスタM5およびM6の信頼性が高められることにより、薄膜トランジスタM5およびM6のサイズを縮小することができる。このように薄膜トランジスタM5およびM6のサイズを縮小することにより、消費電力を低減できる。以上により、本実施形態によれば、消費電力を低減しつつ、薄膜トランジスタM5およびM6の信頼性を高めることができる。また、薄膜トランジスタM5およびM6のサイズを縮小することにより、液晶表示装置の額縁面積を縮小することができる。
図17は、上記第1の実施形態の第1の変形例における1段目(最前段)およびm段目(最後段)以外の双安定回路の構成を示す回路図である。図18は、本変形例における1段目(最前段)の双安定回路の構成を示す回路図である。上記第1の実施形態では各段において薄膜トランジスタMAが設けられていたが、本変形例では、図17および図18に示すように、1段目40(1)~m-1段目40(m-1)に薄膜トランジスタMAが設けられていない。垂直帰線期間の開始時には、図16に示すように1段目第1ノードN1(1)~m-1段目第1ノードN1(m-1)の電位はローレベルとなっているので、1段目40(1)~m-1段目40(m-1)に薄膜トランジスタMAを設けない態様においても、垂直帰線期間において1段目第1ノードN1(1)~m-1段目第1ノードN1(m-1)の電位をローレベルとすることができる。なお、本変形例におけるm段目40(m)については、上記第1の実施形態と同様に薄膜トランジスタMAが設けられている。本変形例によれば、薄膜トランジスタの数が低減されるので、消費電力をさらに低減すると共に、ゲートドライバ400を備える液晶表示装置の額縁面積をさらに縮小することができる。
図19は、上記第1の実施形態の第2の変形例におけるゲートドライバ400の詳細な動作を説明するための信号波形図である。上記第1の実施形態では、1垂直走査期間を駆動周波数60Hz(約16.7msec)で駆動していたが、本変形例では、図19に示すように、1垂直走査期間を駆動周波数30Hz(約33.3msec)で駆動している。例えば、書き込み期間の駆動周波数を60Hz(約16.7msec)とすると、垂直帰線期間の長さが、垂直走査期間の長さの約1/2である約16.7msecとなる。この場合、各段における第2ノードN2の電位のデューティー比が実質的に1/2となるので、上記第1の実施形態と同様の効果が得られる。
図20は、上記第1の実施形態の第3の変形例におけるゲートドライバ400の詳細な動作を説明するための信号波形図である。上記第1の実施形態では、1垂直走査期間を駆動周波数60Hz(約16.7msec)で駆動していたが、本変形例では、図20に示すように、1垂直走査期間を駆動周波数15Hz(約66.6msec)で駆動している。例えば、書き込み期間の駆動周波数を、上記第2の変形例と同様に60Hz(約16.7msec)とすると、垂直帰線期間の長さが、垂直走査期間の長さの約3/4である約50msecとなる。この場合、垂直帰線期間の長さが書き込み期間の長さの約3倍となるので、各段における第2ノードN2の電位のデューティー比が実質的に1/4となる。したがって、薄膜トランジスタM5およびM6のしきい値変動が上記第1の実施形態よりも抑制される。
図21は、上記第1の実施形態の第4の変形例における1段目(最前段)およびm段目(最後段)以外の双安定回路の構成を示す回路図である。上記第1の実施形態では各段において薄膜トランジスタM3およびM4が設けられていたが、本変形例では、図21に示すように、これらの薄膜トランジスタM3およびM4に代えて薄膜トランジスタM10が設けられている。なお、1段目(最前段)およびm段目(最後段)についても同様であるので、それらについての説明及び図示は省略する。この薄膜トランジスタM10については、ゲート端子が第1ノードN1に接続され、ドレイン端子が第2ノードに接続され、ソース端子が直流電源電位Vss用の入力端子に接続されている。この薄膜トランジスタM10は、第1ノードN1の電位がハイレベルとなっているときに、第2ノードN2の電位をVss電位に向けて変化させる。本変形においては、薄膜トランジスタM10によって第2ノードターンオフ用スイッチング素子が実現されている。本変形例によれば、薄膜トランジスタM3およびM4に代えて薄膜トランジスタM10を各双安定回路に設けることにより、セット期間および選択期間において第2ノードN2の電位を確実にローレベルに維持することができる。
<2.1 ゲートドライバの詳細な動作>
図22は、本発明の第2の実施形態におけるゲートドライバ400の詳細な動作を説明するための信号波形図である。なお、液晶表示装置の全体構成および動作と、ゲートドライバ400の構成と、双安定回路の構成および動作と、クロック制御回路420の構成および動作とについては、本実施形態は上記第1の実施形態と同様であるのでこれらの説明を省略する。
本実施形態では、各段における第2ノードN2の電位が、当該段のセット期間および選択期間を除く書き込み期間においてハイレベルとなると共に、当該段のセット期間と、選択期間と、上記休止期間を含む垂直帰線期間とにおいてローレベルとなる。また、本実施形態では、垂直帰線期間の長さが書き込み期間の長さの約2倍となっている。このため、各段における第2ノードN2の電位のデューティー比が実質的に1/3となる。すなわち、薄膜トランジスタM5のゲート端子および薄膜トランジスタM6のゲート端子に与えられる電位のデューティー比が実質的に1/3となる。したがって、本実施形態によれば、薄膜トランジスタM5およびM6のしきい値変動が、上記第1の実施形態と比べてさらに抑制される。このため、薄膜トランジスタM5およびM6の信頼性がさらに高まるので、当該薄膜トランジスタのサイズをさらに小さくすることができる。このように薄膜トランジスタM5およびM6のサイズを小さくした場合には、消費電力をさらに低減すると共に、ゲートドライバ400を備える液晶表示装置の額縁面積をさらに縮小することができる。
<3.1 ゲートドライバの詳細な動作>
図23は、本発明の第3の実施形態におけるゲートドライバ400の詳細な動作を説明するための信号波形図である。なお、液晶表示装置の全体構成および動作と、ゲートドライバ400の構成と、双安定回路の構成および動作と、クロック制御回路420の構成および動作とについては、本実施形態は上記第1の実施形態と同様であるのでこれらの説明を省略する。
本実施形態では、上記第1の実施形態と同様に、各段における第2ノードN2の電位が、当該段のセット期間および選択期間を除く書き込み期間においてハイレベルとなると共に、当該段のセット期間と、選択期間と、上記休止期間を含む垂直帰線期間とにおいてローレベルとなる。また、本実施形態では、垂直帰線期間の長さが書き込み期間の長さの約3倍となっている。このため、各段における第2ノードN2の電位のデューティー比が実質的に1/4となる。すなわち、薄膜トランジスタM5のゲート端子および薄膜トランジスタM6のゲート端子に与えられる電位のデューティー比が実質的に1/4となる。したがって、本実施形態によれば、薄膜トランジスタM5およびM6のしきい値変動が、上記第2の実施形態と比べてさらに抑制される。このため、薄膜トランジスタの信頼性がさらに高まるので、当該薄膜トランジスタのサイズをさらに小さくすることができる。その結果、消費電力をさらに低減すると共に、ゲートドライバ400を備える液晶表示装置の額縁面積をさらに縮小することができる。
<4.1 ゲートドライバの詳細な動作>
図24は、本発明の第4の実施形態におけるゲートドライバ400の詳細な動作を説明するための信号波形図である。なお、液晶表示装置の全体構成および動作と、ゲートドライバ400の構成と、双安定回路の構成および動作と、クロック制御回路420の構成および動作とについては、本実施形態は上記第1の実施形態と同様であるのでこれらの説明を省略する。
本実施形態では、各段における第2ノードN2の電位が、当該段のセット期間および選択期間を除く書き込み期間においてハイレベルとなると共に、当該段のセット期間と、選択期間と、上記休止期間を含む垂直帰線期間とにおいてローレベルとなる。また、本実施形態では、垂直帰線期間の長さが書き込み期間の長さの約1/2倍となっている。このため、各段における第2ノードN2の電位のデューティー比が実質的に2/3となる。すなわち、薄膜トランジスタM5のゲート端子および薄膜トランジスタM6のゲート端子に与えられる電位のデューティー比が実質的に2/3となる。これにより、薄膜トランジスタM5およびM6のしきい値変動が従来よりも抑制される。また、本実施形態における書き込み期間の駆動周波数は、上記第1の実施形態におけるものよりも低速となる。その結果、消費電力がさらに低減すると共に、回路動作がさらに安定する。したがって、本実施形態によれば、消費電力をさらに低減すると共に回路動作をさらに安定させつつ、薄膜トランジスタの信頼性を従来よりも高めることができる。
<5.1 ゲートドライバの電源投入後の動作>
図25は、本発明の第5の実施形態におけるゲートドライバ400での、電源投入後から最初の垂直走査期間の開始時点(ゲートスタートパルス信号GSPが最初にローレベルからハイレベルに変化する時点)までの動作を説明するための信号波形図である。なお、液晶表示装置の全体構成および動作と、ゲートドライバ400の構成および電源投入直後以外の動作と、双安定回路の構成および動作と、クロック制御回路420の構成および動作とについては、本実施形態は上記第1の実施形態と同様であるのでこれらの説明を省略する。
本実施形態によれば、電源投入後から最初の垂直走査期間の開始時点までの期間において不安定となる第1ノードN1の電位および第2ノードN2の電位がローレベルにリセットされる。また、電源投入後から最初の垂直走査期間の開始時点までの期間には、制御前ゲートクロック信号GCKfの各双安定回路への供給が停止した状態となる。このため、第1ノードN1の電位および第2ノードN2の電位が確実にローレベルに維持される。これにより、回路動作をさらに安定させることができる。
<6.1 シフトレジスタの構成および動作>
図26は、本発明の第6の実施形態におけるシフトレジスタ410の、最前段および最後段以外の構成を示すブロック図である。図27は、本実施形態におけるシフトレジスタ410の最前段側の構成を示すブロック図である。図28は、本実施形態におけるシフトレジスタ410の最後段側の構成を示すブロック図である。なお、液晶表示装置の全体構成および動作と、クロック制御回路420の構成および動作とについては、本実施形態は上記第1の実施形態と同様であるのでこれらの説明を省略する。
図29は、本実施形態における、1段目(最前段)およびm段目(最後段)以外の双安定回路の構成を示す回路図である。図29に示すように、この双安定回路は、上述の特許文献1に記載の双安定回路(図32)に、薄膜トランジスタM8、MA、およびMBを追加したものである。また、本実施形態における双安定回路には、上記第1の実施形態における双安定回路と異なり、薄膜トランジスタM4およびM9が設けられていない。この双安定回路には、ローレベルの直流電源電位Vss用の入力端子のほか、5個の入力端子41~44および46と1個の出力端子51とが設けられている。上述のように、この双安定回路には電荷補充用クロック信号CKBを受け取るための入力端子47が設けられていない。
本実施形態における双安定回路の基本的な動作は、上記第1の実施形態におけるものと同様である。したがって、本実施形態および上記第1の実施形態に互いに共通する動作の説明は省略し、互いの相違点のみについて上記図10を参照しつつ説明する。
しかし、本実施形態によっても、薄膜トランジスタM5およびM6のしきい値変動が従来よりも抑制されると共に、ソース端子にクロック信号が与えられる薄膜トランジスタの数が従来よりも少なくなる。その結果、消費電力を低減しつつ、薄膜トランジスタM5およびM6の信頼性を高めることができる。これに加えて、本実施形態によれば、上記第1の実施形態と同様に、薄膜トランジスタM5およびM6の信頼性が高められることにより、これらの薄膜トランジスタM5およびM6のサイズを小さくすることができる。このように薄膜トランジスタM5およびM6のサイズを小さくした場合には、消費電力がさらに低減されると共に、ゲートドライバ400を備えた液晶表示装置の額縁面積を縮小することができる。
本発明におけるゲートドライバ400の構成は、上記各実施形態におけるものに限定されるものではない。すなわち、ゲートドライバ400が、各双安定回路内に少なくとも薄膜トランジスタM5およびM6を備え、2水平走査期間よりも長い垂直帰線期間を設けると共に、この垂直帰線期間において各双安定回路へのクロック信号の供給を停止させ、かつ、この垂直帰線期間において、上記薄膜トランジスタM5のドレイン端子に接続された第1ノードの電位と上記薄膜トランジスタM5およびM6のゲート端子に接続された第2ノードN2の電位とをオフレベルに維持する構成となっていれば良い。例えば、上記第2の従来例において、上記第1の実施形態における薄膜トランジスタM8、MAおよびMBを追加した構成としても良い。なお、上記第2の従来例では、トランジスタT4およびT5が、本発明における薄膜トランジスタM5およびM6に相当する。また、入力部920により第1駆動部61が実現され、プルダウン駆動部940により第2駆動部62が実現され、出力部450により出力部63が実現されている。このような態様において、書き込み期間の長さおよび垂直帰線期間の長さを、上記第1の実施形態におけるものと同様にすると、第2ノードN2が接続されたトランジスタT4およびT5のゲート端子には、ディーティー比が実質的に1/4の電位が与えられることとなる。これにより、このような態様においては、トランジスタT4およびT5に生じるしきい値変動を上記第2の従来例よりも抑制することができる。ただし、このような態様では、第2ノードN2の電位が書き込み期間におけるディーティー比1/2(書き込み期間の長さおよび垂直帰線期間の長さを、上記第1の実施形態におけるものと同様にすると1/4)となるので、この第2ノードN2の電位変動に起因するノイズが第1ノードN2の電位および状態信号Qの電位に生じる。したがって、回路動作の安定性については、上記第1の実施形態のものよりも劣る。
41~44、46、47…入力端子
51…出力端子(出力ノード)
61…第1駆動部
62…第2駆動部
63…出力部
71…第1制御信号生成回路
72…第2制御信号生成回路
73…クロック出力回路
73a…第1のAND回路
73b…第2のAND回路
200…表示制御回路
300…ソースドライバ(映像信号線駆動回路)
400…ゲートドライバ(走査信号線駆動回路)
410…シフトレジスタ
420…クロック制御回路
600…表示部
C1、C2…コンデンサ(容量素子)
M1~M10、MA、MB…薄膜トランジスタ(スイッチング素子)
N1…第1ノード
N2…第2ノード
GCKf1…制御前第1ゲートクロック信号
GCKf2…制御後第2ゲートクロック信号
GCK1…制御後第1ゲートクロック信号
GCK2…制御後第2ゲートクロック信号
GSP…ゲートスタートパルス信号
GEP…ゲートエンドパルス信号
CKA…動作制御用クロック信号
CKB…電荷補充用クロック信号
S…セット信号
R…リセット信号
ST…スタート信号
ED…エンド信号
GOUT(1)~GOUT(m)…走査信号
Vss…ローレベルの直流電源電位
Claims (25)
- 複数の走査信号線を駆動する走査信号線駆動回路であって、
互いに縦続接続された複数の双安定回路を含み、外部から入力されオンレベルとオフレベルとを周期的に繰り返すクロック信号に基づいて前記複数の双安定回路の出力信号を順次にアクティブとするシフトレジスタを備え、
各双安定回路は、
第1ノードに接続され、受け取った信号に基づいて該第1ノードの電位を変化させる第1駆動部と、
第2ノードに接続され、受け取った信号に基づいて該第2ノードの電位を変化させる第2駆動部と、
前記第1ノードおよび前記第2ノードに接続され、該第1ノードの電位および該第2ノード電位がそれぞれオンレベルおよびオフレベルであり、かつ、該第1駆動部が受け取った信号の電位がオフレベルであるときに、アクティブな前記出力信号を前記クロック信号に基づいて出力する出力部とを有し、
前記第1駆動部は、前記第2ノードが制御端子に接続され、前記第1ノードが一方の導通端子に接続され、オフレベルの電位が他方の導通端子に与えられた第1ノードターンオフ用スイッチング素子を有し、
前記出力部は、前記第2ノードが制御端子に接続され、前記出力信号を出力するための出力ノードが一方の導通端子に接続され、オフレベルの電位が他方の導通端子に与えられた出力ノードターンオフ用スイッチング素子を有し、
前記第1駆動部および前記第2駆動部が、各垂直走査期間のうちの2水平走査期間以上の所定期間において前記第1ノードの電位および前記第2ノードの電位をそれぞれオフレベルに維持することを特徴とする、走査信号線駆動回路。 - 前記所定期間において、前記複数の双安定回路への前記クロック信号の供給が停止することを特徴とする、請求項1に記載の走査信号線駆動回路。
- 前記所定期間が長いほど、前記クロック信号の周波数が高くなることを特徴とする、請求項2に記載の走査信号線駆動回路。
- 前記第1駆動部および第2駆動部は、電源投入後から最初の垂直走査期間の開始までの間にさらに、前記第1ノードの電位および前記第2ノードの電位をそれぞれオフレベルに維持し、
電源投入後から最初の垂直走査期間の開始までの間にさらに、前記複数の双安定回路への前記クロック信号の供給が停止することを特徴とする、請求項2に記載の走査信号線駆動回路。 - 前記シフトレジスタにおける最終段の双安定回路の出力信号がアクティブとなった後に該出力信号を非アクティブとするために電位がオンレベルとなるエンド信号に基づいて、前記所定期間において、前記複数の双安定回路への前記クロック信号の供給を停止させるクロック制御回路をさらに備えることを特徴とする、請求項2に記載の走査信号線駆動回路。
- 最終段の双安定回路における第1駆動部は、前記エンド信号が制御端子に与えられ、前記第1ノードが一方の導通端子に接続され、オフレベルの電位が他方の導通端子に与えられた第1エンド用スイッチング素子をさらに有し、
各双安定回路における前記第2駆動部は、前記エンド信号が制御端子に与えられ、前記第2ノードが一方の導通端子に接続され、オフレベルの電位が他方の導通端子に与えられた第2エンド用スイッチング素子を有することを特徴とする、請求項2に記載の走査信号線駆動回路。 - 最終段以外の各段の双安定回路における第1駆動部は、前記第1エンド用スイッチング素子をさらに有することを特徴とする、請求項6に記載の走査信号線駆動回路。
- 最前段以外の各段の双安定回路における第2駆動部は、各垂直走査期間の開始のタイミングでオンレベルとなるスタート信号に基づいて、前記第2ノードの電位をオンレベルに向けて変化させるスタート用スイッチング素子をさらに有することを特徴とする、請求項6に記載の走査信号線駆動回路。
- 前記第1駆動部は、セット信号に基づいて、前記第1ノードの電位をオンレベルに向けて変化させる第1ノードターンオン用スイッチング素子をさらに有し、
最前段の双安定回路における前記セット信号は、前記スタート信号であり、
最前段以外の双安定回路における前記セット信号は、該双安定回路の前段の双安定回路の出力信号であることを特徴とする、請求項8に記載の走査信号線駆動回路。 - 前記出力部は、
前記第1ノードが制御端子に接続され、前記クロック信号が一方の導通端子に与えられ、前記出力ノードが他方の導通端子に接続された出力制御用スイッチング素子と、
前記出力制御用スイッチング素子の前記制御端子が一端に接続され、前記出力ノードが他端に接続された容量素子とをさらに有することを特徴とする、請求項9に記載の走査信号線駆動回路。 - 前記第2駆動部は、前記第2ノードが一方の導通端子に接続され、オフレベルの電位が他方の導通端子に与えられた第2ノードターンオフ用スイッチング素子をさらに有することを特徴とする、請求項10に記載の走査信号線駆動回路。
- 前記第2駆動部には、前記第2ノードターンオフ用スイッチング素子として、
前記セット信号が制御端子に与えられ、前記第2ノードが一方の導通端子に接続され、オフレベルの電位が他方の導通端子に与えられた第1の第2ノードターンオフ用スイッチング素子と、
前記出力ノードが制御端子に接続され、前記第2ノードが一方の導通端子に接続され、オフレベルの電位が他方の導通端子に与えられた第2の第2ノードターンオフ用スイッチング素子とが設けられていることを特徴とする、請求項11に記載の走査信号線駆動回路。 - 前記第2ノードターンオフ用スイッチング素子の制御端子は、前記第1ノードに接続されていることを特徴とする、請求項11に記載の走査信号線駆動回路。
- 最前段以外の各段の双安定回路における第2駆動部は、該双安定回路の後段の双安定回路の出力信号に基づいて、前記第2ノードの電位をオンレベルに向けて変化させる第2ノードターンオン用スイッチング素子をさらに有することを特徴とする、請求項11に記載の走査信号線駆動回路。
- 前記クロック信号は、互いに1水平走査期間だけ位相がずれた第1クロック信号および第2クロック信号からなり、
前記出力制御用スイッチング素子の一方の導通端子には前記第1クロック信号が与えられ、
前記第2駆動部は、前記第2クロック信号に基づいて前記第2ノードの電位をオンレベルに向けて変化させる電荷補充用スイッチング素子をさらに有することを特徴とする、請求項11に記載の走査信号線駆動回路。 - 複数の走査信号線が配置された表示部と、
前記複数の走査信号線を駆動する走査信号線駆動回路と
前記走査信号線駆動回路に、オンレベルとオフレベルとを周期的に繰り返すクロック信号を供給する表示制御回路とを備え、
前記走査信号線駆動回路は、互いに縦続接続された複数の双安定回路を有し、前記クロック信号に基づいて前記複数の双安定回路の出力信号を順次にアクティブとするシフトレジスタを含み、
各双安定回路は、
第1ノードに接続され、受け取った信号に基づいて該第1ノードの電位を変化させる第1駆動部と、
第2ノードに接続され、受け取った信号に基づいて該第2ノードの電位を変化させる第2駆動部と、
前記第1ノードおよび前記第2ノードに接続され、該第1ノードの電位および該第2ノード電位がそれぞれオンレベルおよびオフレベルであり、かつ、該第1駆動部が受け取った信号の電位がオフレベルであるときに、アクティブな前記出力信号を前記クロック信号に基づいて出力する出力部とを有し、
前記第1駆動部は、前記第2ノードが制御端子に接続され、前記第1ノードが一方の導通端子に接続され、オフレベルの電位が他方の導通端子に与えられた第1ノードターンオフ用スイッチング素子を有し、
前記出力部は、前記第2ノードが制御端子に接続され、前記出力信号を出力するための出力ノードが一方の導通端子に接続され、オフレベルの電位が他方の導通端子に与えられた出力ノードターンオフ用スイッチング素子を有し、
前記第1駆動部および前記第2駆動部が、各垂直走査期間のうちの2水平走査期間以上の所定期間において前記第1ノードの電位および前記第2ノードの電位をそれぞれオフレベルに維持することを特徴とする、表示装置。 - 前記所定期間において、前記複数の双安定回路への前記クロック信号の供給が停止することを特徴とする、請求項16に記載の表示装置。
- 前記走査信号線駆動回路は、前記シフトレジスタにおける最終段の双安定回路の出力信号がアクティブとなった後に該出力信号を非アクティブとするために電位がオンレベルとなるエンド信号に基づいて、前記所定期間において、前記複数の双安定回路への前記クロック信号の供給を停止させるクロック制御回路をさらに含むことを特徴とする、請求項17に記載の表示装置。
- 前記表示制御回路は、前記所定期間において、前記複数の双安定回路への前記クロック信号の供給を停止することを特徴とする、請求項17に記載の表示装置。
- 前記表示制御回路は、前記所定期間が長いほど、前記クロック信号の周波数を高めることを特徴とする、請求項17に記載の表示装置。
- 前記表示部と前記走査信号線駆動回路とは一体的に形成されていることを特徴とする、請求項16から20までのいずれか一項に記載の表示装置。
- 互いに縦続接続された複数の双安定回路を含み、外部から入力されオンレベルとオフレベルとを周期的に繰り返すクロック信号に基づいて前記複数の双安定回路の出力信号を順次にアクティブとするシフトレジスタを備えた走査信号線駆動回路による、複数の走査信号線の駆動方法であって、
各双安定回路において信号を受け取り、該信号に基づいて、該双安定回路における第1ノードの電位を変化させるステップと、
各双安定回路において信号を受け取り、該信号に基づいて、該双安定回路における第2ノードの電位を変化させるステップと、
前記第1ノードの電位および前記第2ノードの電位がそれぞれオンレベルおよびオフレベルであり、かつ、前記第1ノードの電位を変化させるステップにおいて各双安定回路が受け取った信号の電位がオフレベルであるときに、アクティブな前記出力信号を出力するステップとを備え、
各双安定回路は、
前記第2ノードが制御端子に接続され、前記第1ノードが一方の導通端子に接続され、オフレベルの電位が他方の導通端子に与えられた第1ノードターンオフ用スイッチング素子と、
前記第2ノードが制御端子に接続され、前記出力信号を出力するための出力ノードが一方の導通端子に接続され、オフレベルの電位が他方の導通端子に与えられた出力ノードターンオフ用スイッチング素子を有し、
前記第1ノードの電位を変化させるステップでは、各垂直走査期間のうちの2水平走査期間以上の所定期間において前記第1ノードの電位がオフレベルに維持され、
前記第2ノードの電位を変化させるステップでは、前記所定期間において前記第2ノードの電位がオフレベルに維持されることを特徴とする、駆動方法。 - 前記所定期間において、前記複数の双安定回路への前記クロック信号の供給を停止するステップをさらに備えることを特徴とする、請求項22に記載の駆動方法。
- 前記所定期間が長いほど、前記クロック信号の周波数が高くなることを特徴とする、請求項23に記載の駆動方法
- 前記第1ノードの電位を変化させるステップでは、電源投入後から最初の垂直走査期間の開始までの間にさらに、前記第1ノードの電位がオフレベルに維持され、
前記第2ノードの電位を変化させるステップでは、電源投入後から最初の垂直走査期間の開始までの間にさらに、前記第2ノードの電位がオフレベルに維持され、
前記クロック信号の供給を停止するステップでは、電源投入後から最初の垂直走査期間の開始までの間にさらに、前記クロック信号の供給が停止されることを特徴とする、請求項23に記載の駆動方法。
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- 2012-05-16 WO PCT/JP2012/062474 patent/WO2012161042A1/ja active Application Filing
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WO2014092011A1 (ja) * | 2012-12-14 | 2014-06-19 | シャープ株式会社 | 表示装置およびその駆動方法 |
US9666140B2 (en) | 2012-12-14 | 2017-05-30 | Sharp Kabushiki Kaisha | Display device and method for driving same |
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US9466254B2 (en) | 2013-12-20 | 2016-10-11 | Boe Technology Group Co., Ltd. | Shift register unit, gate driving circuit and display apparatus |
JP2018508809A (ja) * | 2014-12-30 | 2018-03-29 | 深▲セン▼市華星光電技術有限公司 | 液晶ディスプレイとそのゲート駆動装置 |
JP2018018050A (ja) * | 2016-07-29 | 2018-02-01 | エルジー ディスプレイ カンパニー リミテッド | ゲートドライバ、表示装置及びゲートドライバの駆動方法 |
US10176746B2 (en) | 2016-07-29 | 2019-01-08 | Lg Display Co., Ltd. | Display device, gate driver and method of driving gate driver |
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US10909942B2 (en) | 2016-08-05 | 2021-02-02 | Sakai Display Products Corporation | Drive circuit and display apparatus |
Also Published As
Publication number | Publication date |
---|---|
CN103503057A (zh) | 2014-01-08 |
US9362892B2 (en) | 2016-06-07 |
JP5372268B2 (ja) | 2013-12-18 |
US20140111495A1 (en) | 2014-04-24 |
KR101552420B1 (ko) | 2015-09-10 |
CN103503057B (zh) | 2016-02-10 |
KR20140033139A (ko) | 2014-03-17 |
JPWO2012161042A1 (ja) | 2014-07-31 |
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