Display apparatus and electronic apparatus

Abstract

A display apparatus includes a pixel unit in which pixels are arranged in a matrix pattern; and a driving circuit for driving the pixel unit. Each of the pixels includes a signal level holding capacitor; a first transistor that is turned on/off in response to a writing signal and via which one end of the signal level holding capacitor is connected to a signal line; a second transistor having one end of the signal level holding capacitor connected to a gate thereof and the other end of the signal level holding capacitor connected to a source thereof; a current-driven self-light-emitting element whose cathode is held at a cathode potential and whose anode is connected to the source of the second transistor; a third transistor that is turned on/off in response to a driving pulse signal; and a fourth transistor that is turned on/off in response to a control signal.

What is claimed is: 
     
       1. A display apparatus comprising:
 a pixel unit in which pixels are arranged in a matrix pattern; and a driving circuit for driving the pixel unit, 
 wherein each of the pixels includes 
 a capacitor; 
 a first transistor that is turned on/off in response to a writing signal and via which one end of the capacitor is connected to a signal line; 
 a second transistor; 
 a light-emitting element which is connected to the second transistor; 
 a third transistor that is turned on/off in response to a driving pulse signal and via which the drain of the second transistor is connected to a power-supply voltage; and 
 a fourth transistor that is turned on/off in response to a control signal and that sets the other end of the signal level holding capacitor to a first fixed potential, and wherein the driving circuit sequentially sets the signal level of the signal line to a signal level and a second fixed potential, 
 wherein during the period of time in which the signal level of the signal line is set to the second fixed potential, sets the third transistor to an on state. 
 
     
     
       2. The electronic apparatus including the display apparatus according to  claim 1 . 
     
     
       3. A display apparatus comprising:
 a pixel unit in which pixels are arranged in a matrix pattern; and a driving circuit for driving the pixel unit,   wherein each of the pixels includes   a signal level holding capacitor;   a first transistor that is turned on/off in response to a writing signal and via which one end of the signal level holding capacitor is connected to a signal line;   a second transistor;   a light-emitting element which is connected to the second transistor;   a third transistor that is turned on/off in response to a driving pulse signal and via which a drain of the second transistor is connected to a power-supply voltage; and   a fourth transistor that is turned on/off in response to a control signal and that sets an other end of the signal level holding capacitor to a first fixed potential   wherein the driving circuit sequentially sets a signal level of the signal line to a signal level potential and a second fixed potential and   wherein during a period of time in which the signal level of the signal line is set to the second fixed potential the driving circuit sets the third transistor to an on state.   
     
     
       4. The display apparatus according to claim 3, wherein a gate of the second transistor is connected to the one end of the signal level holding capacitor. 
     
     
       5. The display apparatus according to claim 3, wherein a source of the second transistor is connected to the other end of the signal level holding capacitor. 
     
     
       6. The display apparatus according to claim 3, wherein a gate of the second transistor is connected to the one end of the signal level holding capacitor, a source of the second transistor is connected to the other end of the signal level holding capacitor. 
     
     
       7. The display apparatus according to claim 3, wherein the driving circuit includes a vertical driving circuit and a horizontal driving circuit. 
     
     
       8. The display apparatus according to claim 7, wherein the vertical driving circuit is configured to output the writing signal, the driving pulse signal, and the control signal. 
     
     
       9. The display apparatus according to claim 7, wherein the horizontal driving circuit is configured to sequentially sets the signal level of the signal line to a gray-scale level and the second fixed potential. 
     
     
       10. The display apparatus according to claim 3, wherein:
 in a first period, the driving circuit sets the first and fourth transistors to an off state and sets the third transistor to an on state;   in a second period after the first period, the driving circuit sets the third transistor to an off state;   in a third period after the second period, the driving circuit sets the fourth transistor to an on state and sets the first transistor to an on state;   in a fourth period after the third period, the driving circuit sets the first transistor to an on state, sets the fourth transistor to an off state, sets the signal level of the signal line to the second fixed potential, and sets the third transistor to an on state; and   in a fifth period after the fourth period, the driving circuit sets the first transistor to an off state and sets the signal level of the signal line to the signal level potential.   
     
     
       11. The display apparatus according to claim 10, wherein the first to fifth periods are cyclically repeated. 
     
     
       12. The display apparatus according to claim 10, wherein, in the fifth period, the driving circuit sets the third transistor to an on state, and sets the first transistor to an off state after a predetermined period of time passes. 
     
     
       13. The display apparatus according to claim 10, wherein, in the fourth period, the driving circuit sets the signal level of the signal line to the second fixed potential in a plurality of times. 
     
     
       14. The display apparatus according to claim 3, wherein each of the first transistor, the second transistor, the third transistor, and the fourth transistor is N-channel transistor. 
     
     
       15. The display apparatus according to claim 3, wherein the pixel unit and the driving circuit are arranged on an insulating substrate. 
     
     
       16. The display apparatus according to claim 15, wherein the pixel unit and the driving circuit are formed on the insulating substrate with an amorphous silicon process. 
     
     
       17. The display apparatus according to claim 3, wherein during the period of time in which the signal level of the signal line is set to the second fixed potential, the driving circuit sets the third transistor to an on state so as to set the potential difference across the ends of the signal level holding capacitor to a voltage approximately equal to a threshold voltage of the second transistor. 
     
     
       18. The display apparatus according to claim 3, wherein the signal level potential corresponds to a gray-scale level. 
     
     
       19. The display apparatus according to claim 18, wherein a gate of the second transistor is connected to the one end of the signal level holding capacitor, a source of the second transistor is connected to the other end of the signal level holding capacitor. 
     
     
       20. The display apparatus according to claim 18, wherein:
 in a first period, the driving circuit sets the first and fourth transistors to an off state and sets the third transistor to an on state;   in a second period after the first period, the driving circuit sets the third transistor to an off state;   in a third period after the second period, the driving circuit sets the fourth transistor to an on state and sets the first transistor to an on state;   in a fourth period after the third period, the driving circuit sets the first transistor to an on state, sets the fourth transistor to an off state, sets the signal level of the signal line to the second fixed potential, and sets the third transistor to an on state; and   in a fifth period after the fourth period, the driving circuit sets the first transistor to an off state and sets the signal level of the signal line to the gray-scale level.   
     
     
       21. The display apparatus according to claim 20, wherein the first to fifth periods are cyclically repeated. 
     
     
       22. An electronic apparatus including the display apparatus according to claim 3.