Display device, method for driving display device, and electronic device
A display device according to the present disclosure includes: a pixel array unit ( 30 ) in which pixel circuits ( 20 A) are disposed in a matrix form, the pixel circuits each including a light emission unit ( 21 ), a write transistor ( 23 ) that writes a signal voltage (Vsig) of a video signal, a retention capacitor ( 24 ) that retains the signal voltage (Vsig) written by the write transistor ( 23 ), a drive transistor ( 22 ) that drives the light emission unit ( 21 ) on the basis of the signal voltage (Vsig) retained by the retention capacitor ( 24 ), and an auxiliary capacitor ( 25 ) of which one terminal is connected to a source node of the drive transistor ( 22 ); and a control unit ( 90 ) that provides a potential change to a source electrode of the drive transistor ( 22 ) by coupling through the auxiliary capacitor ( 25 ) to set an operation point of the drive transistor ( 22 ) as a cut-off region after the threshold value correction process.
1. A display device comprising:
a pixel array unit including pixel circuits disposed in a matrix form, at least one of the pixel circuits including a light emission unit, a write transistor that writes a signal voltage of a video signal, a retention capacitor that retains the signal voltage written by the write transistor, a drive transistor that drives the light emission unit according to the signal voltage retained by the retention capacitor, and an auxiliary capacitor with a first terminal connected to a source electrode of the drive transistor, the pixel circuit being configured to execute a threshold value correction process that changes a source voltage of the drive transistor such that the source voltage becomes a difference between a threshold value voltage of the drive transistor and an initialization voltage of a gate electrode of the drive transistor; and
control circuitry that provides a potential change to the source electrode of the drive transistor by coupling through the auxiliary capacitor to set an operation point of the drive transistor as a cut-off region after the threshold value correction process,
wherein a write scanning signal enters an active state a first time during the threshold value correction process and a second time during the writing of the signal voltage, and
wherein when the write scanning signal enters the active state the first time and the second time, the respective pulse widths are the same.
2. The display device according to claim 1 ,
wherein the control circuitry changes a potential of the source electrode of the drive transistor by providing the potential change to a second terminal of the auxiliary capacitor.
3. The display device according to claim 2 ,
wherein the second terminal of the auxiliary capacitor is connected to a control line, and
the control circuitry provides the potential change to the source electrode of the drive transistor by switching a control signal provided to the second terminal of the auxiliary capacitor through the control line from a non-active state to an active state.
4. The display device according to claim 3 , further comprising:
write scanning circuitry that drives the write transistor through a scanning line in units of rows,
wherein the control circuitry and the write scanning circuitry are provided in a peripheral circuit region on the same side with respect to the pixel array unit.
5. The display device according to claim 4 ,
wherein the control line and the scanning line are formed of same wire material and have same thickness and same width.
6. The display device according to claim 1 ,
wherein the source voltage of the drive transistor when the potential change is provided to the source electrode of the drive transistor is a voltage smaller than at least the sum of a cathode voltage of the light emission unit and a threshold value voltage of the light emission unit.
7. The display device according to claim 1 ,
wherein the write transistor writes a signal voltage into the gate electrode of the drive transistor after the potential change is provided to the source electrode of the drive transistor.
8. The display device according to claim 1 ,
wherein the pixel circuit performs a mobility correction process during the second time that the write scanning signal enters the active state, the mobility correction process applies a negative feedback to a potential difference between the gate electrode and the source electrode of the drive transistor, the negative feedback being a correction amount corresponding to a current flowing in the drive transistor, thereby correcting a mobility of the drive transistor.
9. A method for driving a display device comprising a pixel array unit including pixel circuits disposed in a matrix form, at least one of the pixel circuits including a light emission unit, a write transistor that writes a signal voltage of a video signal, a retention capacitor that retains the signal voltage written by the write transistor, a drive transistor that drives the light emission unit according to the signal voltage retained by the retention capacitor, and an auxiliary capacitor with a first terminal connected to a source electrode of the drive transistor, the pixel circuit being configured to execute a threshold value correction process that changes a source voltage of the drive transistor such that the source voltage becomes a difference between a threshold value voltage of the drive transistor and an initialization voltage of a gate electrode of the drive transistor, the method comprising:
providing a potential change to the source electrode of the drive transistor by coupling through the auxiliary capacitor to set an operation point of the drive transistor as a cut-off region after the threshold value correction process, and
entering an active state a first time during the threshold value correction process and a second time during the writing of the signal voltage, wherein when entering the active state the first time and the second time, the respective pulse widths are the same.
10. An electronic device comprising
a display device comprising:
a pixel array unit including pixel circuits disposed in a matrix form, at least one of the pixel circuits including a light emission unit, a write transistor that writes a signal voltage of a video signal, a retention capacitor that retains the signal voltage written by the write transistor, a drive transistor that drives the light emission unit according to the signal voltage retained by the retention capacitor, and an auxiliary capacitor with a first terminal connected to a source electrode of the drive transistor, the pixel circuit being configured to execute a threshold value correction process that changes a source voltage of the drive transistor such that the source voltage becomes a difference between a threshold value voltage of the drive transistor and an initialization voltage of a gate electrode of the drive transistor; and
control circuitry that provides a potential change to the source electrode of the drive transistor by coupling through the auxiliary capacitor to set an operation point of the drive transistor as a cut-off region after the threshold value correction process,
wherein a write scanning signal enters an active state a first time during the threshold value correction process and a second time during the writing of the signal voltage, and
wherein when the write scanning signal enters the active state the first time and the second time, the respective pulse widths are the same.