Patent ID: 8004477
Filing Date: 2011-08-23
Classification: G09G

Abstract:
1. A display apparatus including a pixel-array unit, a scanner unit and a signal unit, wherein: said pixel-array unit has pixels laid out to form a matrix and each provided at an intersection of first and second scanning lines each oriented in a row direction of said matrix and a signal line oriented in a column direction of said matrix; said signal unit provides a video signal to said signal line; said scanner unit sequentially scans said pixels of said matrix in row units by supplying first and second control signals to said first and second scanning lines respectively; each of said pixels includes a sampling transistor, a pixel capacitor connected to said sampling transistor, a drive transistor connected to said sampling transistor as well as said pixel capacitor, a light emitting device connected to said drive transistor, and a switching transistor for connecting said drive transistor to a power supply; said first control signal supplied by said scanner unit through said first scanning line causes said sampling transistor to enter a conductive state of sampling the electric potential of a video signal supplied by said signal unit to said signal line and storing said sampled electric potential in said pixel capacitor; said pixel capacitor applies an input voltage to the gate of said drive transistor in accordance with said sampled electric potential of said video signal; said drive transistor supplies an output current according to said input voltage to said light emitting device as an output current exhibiting a characteristic of dependence on the threshold voltage of said drive transistor; the output current generated by said drive transistor causes said light emitting device to emit a light beam with a luminance according to said electric potential of said video signal during a light emission period; said second control signal supplied by said scanner unit through said second scanning line causes said switching transistor to enter a conductive state of connecting said drive transistor to said power supply during said light emission period; during a period other than said light emission period, said switching transistor is put in a non-conductive state in order to disconnect said drive transistor from said power supply; during a horizontal scanning period, said scanner unit supplies said first control signal to said first scanning line in a control operation to put said sampling transistor in on and off states and said second control signal to said second scanning line in a control operation to put said switching transistor in on and off states and, in order to compensate said pixel capacitor for an effect of said characteristic exhibited by the output current of said drive transistor as a characteristic of dependence on said threshold voltage of said drive transistor, said pixel carries out: wherein said drive transistor exhibits a characteristic displaying dependence of an output current generated by said drive transistor on a mobility of carriers in a channel area in said drive transistor in addition to dependence on a threshold voltage of said drive transistor; and a mobility compensatory operation to compensate an input voltage applied to said drive transistor for an effect of said characteristic showing dependence of the output current on said mobility of carriers by drawing the output current from said drive transistor with a signal electric potential sampled and feeding back said drawn output current to said pixel capacitor in a negative feedback operation.