Display device, method for driving same, and electronic apparatus
View Patent ↗In an embodiment of the present invention, a signal driver employs a two-stage system in which the potential of a signal line (SL) is switched from a reference potential (Vofs) to an intermediate potential (Vofs 2 ), and then switched to a signal potential (Vsig) of a video signal. A scanner supplies a first control pulse to a scan line (WS) when the signal line (SL) is at the intermediate potential (Vofs 2 ), and then supplies a second control pulse to thereby turn on and off a sampling transistor T 1 when the signal line (SL) is at the signal potential (Vsig). Based on this configuration, two times of mobility correction (μ correction) are carried out.
1. A display device comprising:
a pixel array part configured to include scan lines disposed along rows, signal lines disposed along columns, and pixels that are disposed at intersections of the scan lines and the signal lines and arranged in a matrix; and
a drive part configured to drive the pixels via the scan lines and the signal lines, wherein
the pixel includes at least a sampling transistor, a drive transistor, a hold capacitor, and a light-emitting element,
a control terminal of the sampling transistor is connected to the scan line, and a pair of current terminals of the sampling transistor are connected between the signal line and a control terminal of the drive transistor,
a current terminal of the drive transistor is connected to the light-emitting element,
the hold capacitor is connected between the control terminal of the drive transistor and the current terminal of the drive transistor,
the drive part has a scanner that sequentially supplies a control signal to the scan lines and a driver that supplies a video signal to the signal lines,
in the pixel, the sampling transistor is turned on in response to the control signal to sample the video signal and write the video signal to the hold capacitor, and a current that flows through the drive transistor at the time of the writing of the video signal is subjected to negative feedback to the hold capacitor from the current terminal of the drive transistor to carry out correction for mobility of the drive transistor, and a drive current is supplied from the drive transistor to the light-emitting element depending on a corrected video signal following the correction,
the driver switches a potential of the signal line from a reference potential to an intermediate potential before switching the potential of the signal line to a signal potential of the video signal, for the writing of the video signal to the hold capacitor, and
the scanner supplies a first control signal pulse to turn on and off the sampling transistor when the signal line is at the intermediate potential, and then supplies a second control signal pulse to turn on and off the sampling transistor when the signal line is at the signal potential,
wherein said intermediate potential is different from said reference potential and said signal potential, and said intermediate potential is between said reference potential and said signal potential.
2. The display device according to claim 1 , wherein
the scanner keeps a potential of the scan line at a predetermined potential during a period from falling-down of the first control signal pulse to rising-up of the second control signal pulse,
if the signal potential is higher than a potential obtained by subtracting a threshold voltage of the sampling transistor from the predetermined potential, the sampling transistor is turned on in response to rising-up of the first control signal pulse and turned off in response to the falling-down of the first control signal pulse, and then the sampling transistor is turned on in response to the rising-up of the second control signal pulse and turned off in response to falling-down of the second control signal pulse, and
if the signal potential is lower than the potential obtained by subtracting the threshold voltage of the sampling transistor from the predetermined potential, the sampling transistor is kept at an on-state during a period from the rising-up of the first control signal pulse to the falling-down of the second control signal pulse.
3. The display device according to claim 1 , wherein
the sampling transistor is kept at an off-state during a period from falling-down of the first control signal pulse to rising-up of the second control signal pulse, and
during the period, a potential of the control terminal of the drive transistor increases in such a way that potential difference between the control terminal of the drive transistor and the current terminal of the drive transistor is kept constant.
4. An Electronic apparatus comprising
a display device including
a pixel array part configured to include scan lines disposed along rows, signal lines disposed along columns, and pixels that are disposed at intersections of the scan lines and the signal lines and arranged in a matrix;
and a drive part configured to drive the pixels via the scan lines and the signal lines, wherein
the pixel includes at least a sampling transistor, a drive transistor, a hold capacitor, and a light-emitting element,
a control terminal of the sampling transistor is connected to the scan line, and a pair of current terminals of the sampling transistor are connected between the signal line and a control terminal of the drive transistor,
a current terminal of the drive transistor is connected to the light-emitting element,
the hold capacitor is connected between the control terminal of the drive transistor and the current terminal of the drive transistor,
the drive part has a scanner that sequentially supplies a control signal to the scan lines and a driver that supplies a video signal to the signal lines,
in the pixel, the sampling transistor is turned on in response to the control signal to sample the video signal and write the video signal to the hold capacitor, and a current that flows through the drive transistor at the time of the writing of the video signal is subjected to negative feedback to the hold capacitor from the current terminal of the drive transistor to carry out correction for mobility of the drive transistor, and a drive current is supplied from the drive transistor to the light-emitting element depending on a corrected video signal following the correction,
the driver switches a potential of the signal line from a reference potential to an intermediate potential before switching the potential of the signal line to a signal potential of the video signal, for the writing of the video signal to the hold capacitor, and
the scanner supplies a first control signal pulse to turn on and off the sampling transistor when the signal line is at the intermediate potential, and then supplies a second control signal pulse to turn on and off the sampling transistor when the signal line is at the signal potential,
wherein said intermediate potential is different from said reference potential and said signal potential, and said intermediate potential is between said reference potential and said signal potential.
5. A method for driving a display device that includes a pixel array part and a drive part, the pixel array part including scan lines disposed along rows, signal lines disposed along columns, and pixels that are disposed at intersections of the scan lines and the signal lines and arranged in a matrix, the drive part driving the pixels via the scan lines and the signal lines, the pixel including at least a sampling transistor, a drive transistor, a hold capacitor, and a light-emitting element, a control terminal of the sampling transistor being connected to the scan line, a pair of current terminals of the sampling transistor being connected between the signal line and a control terminal of the drive transistor, a current terminal of the drive transistor being connected to the light-emitting element, the hold capacitor being connected between the control terminal of the drive transistor and the current terminal of the drive transistor, the drive part having a scanner that sequentially supplies a control signal to the scan lines and a driver that supplies a video signal to the signal lines, the sampling transistor being turned on in response to the control signal to sample the video signal and write the video signal to the hold capacitor, a current that flows through the drive transistor at the time of the writing of the video signal being subjected to negative feedback to the hold capacitor from the current terminal of the drive transistor to carry out correction for mobility of the drive transistor, a drive current being supplied from the drive transistor to the light-emitting element depending on a corrected video signal following the correction, the method comprising the steps of:
switching, by the driver, a potential of the signal line from a reference potential to an intermediate potential before switching the potential of the signal line to a signal potential of the video signal, for the writing of the video signal to the hold capacitor; and
supplying a first control signal pulse from the scanner to turn on and off the sampling transistor when the signal line is at the intermediate potential, and then supplying a second control signal pulse from the scanner to turn on and off the sampling transistor when the signal line is at the signal potential,
wherein said intermediate potential is different from said reference potential and said signal potential, and said intermediate potential is between said reference potential and said signal potential.
6. A display device comprising:
pixel arraying means for including scan lines disposed along rows, signal lines disposed along columns, and pixels that are disposed at intersections of the scan lines and the signal lines and arranged in a matrix; and
driving means for driving the pixels via the scan lines and the signal lines, wherein
the pixel includes at least a sampling transistor, a drive transistor, a hold capacitor, and a light-emitting element,
a control terminal of the sampling transistor is connected to the scan line, and a pair of current terminals of the sampling transistor are connected between the signal line and a control terminal of the drive transistor,
a current terminal of the drive transistor is connected to the light-emitting element,
the hold capacitor is connected between the control terminal of the drive transistor and the current terminal of the drive transistor,
driving means has a scanner that sequentially supplies a control signal to the scan lines and a driver that supplies a video signal to the signal lines,
in the pixel, the sampling transistor is turned on in response to the control signal to sample the video signal and write the video signal to the hold capacitor, and a current that flows through the drive transistor at the time of the writing of the video signal is subjected to negative feedback to the hold capacitor from the current terminal of the drive transistor to carry out correction for mobility of the drive transistor, and a drive current is supplied from the drive transistor to the light-emitting element depending on a corrected video signal following the correction,
the driver switches a potential of the signal line from a reference potential to an intermediate potential before switching the potential of the signal line to a signal potential of the video signal, for the writing of the video signal to the hold capacitor, and
the scanner supplies a first control signal pulse to turn on and off the sampling transistor when the signal line is at the intermediate potential, and then supplies a second control signal pulse to turn on and off the sampling transistor when the signal line is at the signal potential,
wherein said intermediate potential is different from said reference potential and said signal potential, and said intermediate potential is between said reference potential and said signal potential.
7. The electronic apparatus according to claim 4 , wherein
the scanner keeps a potential of the scan line at a predetermined potential during a period from falling-down of the first control signal pulse to rising-up of the second control signal pulse,
if the signal potential is higher than a potential obtained by subtracting a threshold voltage of the sampling transistor from the predetermined potential, the sampling transistor is turned on in response to rising-up of the first control signal pulse and turned off in response to the falling-down of the first control signal pulse, and then the sampling transistor is turned on in response to the rising-up of the second control signal pulse and turned off in response to falling-down of the second control signal pulse, and
if the signal potential is lower than the potential obtained by subtracting the threshold voltage of the sampling transistor from the predetermined potential, the sampling transistor is kept at an on-state during a period from the rising-up of the first control signal pulse to the falling-down of the second control signal pulse.
8. The electronic apparatus according to claim 4 , wherein
the sampling transistor is kept at an off-state during a period from falling-down of the first control signal pulse to rising-up of the second control signal pulse, and
during the period, a potential of the control terminal of the drive transistor increases in such a way that potential difference between the control terminal of the drive transistor and the current terminal of the drive transistor is kept constant.
9. The method for driving the display device according to claim 5 , wherein the supplying further comprises
keeping, by the scanner, a potential of the scan line at a predetermined potential during a period from falling-down of the first control signal pulse to rising-up of the second control signal pulse,
turning the sampling transistor on in response to rising-up of the first control signal pulse and turned off in response to the falling-down of the first control signal pulse if the signal potential is higher than a potential obtained by subtracting a threshold voltage of the sampling transistor from the predetermined potential, and then turning the sampling transistor on in response to the rising-up of the second control signal pulse and turning the sampling transistor off in response to falling-down of the second control signal pulse, and
keeping the sampling transistor at an on-state during a period from the rising-up of the first control signal pulse to the falling-down of the second control signal pulse if the signal potential is lower than the potential obtained by subtracting the threshold voltage of the sampling transistor from the predetermined potential.
10. The method for driving a display device according to claim 5 further includes the steps of
keeping the sampling transistor at an off-state during a period from falling-down of the first control signal pulse to rising-up of the second control signal pulse, and
said keeping further comprising increasing a potential of the control terminal of the drive transistor in such a way that potential difference between the control terminal of the drive transistor and the current terminal of the drive transistor is kept constant.