Display apparatus, light detection method and electronic apparatus
Disclosed herein is a display apparatus including a plurality of pixel circuits, a displaying driving section, and a light amount information detection section. The pixel circuits are disposed in a matrix at positions at which a signal line and a plurality of scanning lines cross with each other. The displaying driving section applies a signal value to each pixel circuit and drives the scanning lines to cause the pixel circuit to emit light with a luminance according to the signal value to carry out image display. The light amount information detection section detects light amount information. Each pixel circuit includes a light emitting element, a driving transistor, a sampling transistor, and a switching transistor. Each pixel circuit can execute light detection operation of varying the gate potential of the driving transistor in response to a received light amount and outputting the source potential of the driving transistor.
1 . A display apparatus, comprising:
a plurality of pixel circuits disposed in a matrix at positions at which a signal line and a plurality of scanning lines cross with each other;
a displaying driving section adapted to apply a signal value to each of said pixel circuits through the signal line and drive the scanning lines to cause the pixel circuit to carry out light emission with a luminance in accordance with the signal value to carry out image display; and
a light amount information detection section adapted to detect light amount information from an output of each of said pixel circuits to a light detection line disposed for the pixel circuit;
each of said pixel circuits including
a light emitting element,
a driving transistor for carrying out application of current to said light emitting element in response to a signal value voltage inputted thereto,
a sampling transistor for inputting, when said sampling transistor is switched on, the signal value from the signal line to the gate of said driving transistor, and
a switching transistor connected between an end of said driving transistor and the light detection line;
each of said pixel circuits being capable of executing light detection operation of varying the gate potential of said driving transistor in response to a received light amount and outputting the source potential of said driving transistor in accordance with the potential variation to the light detection line through said switching transistor.
2 . The display apparatus according to claim 1 , wherein said sampling transistor is structured so as to function as a light sensor in an off state thereof, and applies, as the light detection operation, when the sampling transistor is placed in an off state, leak current in response to the received light amount to the gate of said driving transistor to vary the gate potential of said driving transistor in response to the received light amount.
3 . The display apparatus according to claim 2 , wherein said sampling transistor in the pixel circuit receives light from said light emitting element in the pixel circuit itself.
4 . The display apparatus according to claim 2 , wherein said sampling transistor in the pixel circuit receives light from the light emitting element in a neighboring pixel circuit.
5 . The display apparatus according to claim 2 , wherein the light detection line is charged to the potential with which said light emitting element does not emit light.
6 . The display apparatus according to claim 2 , wherein each of said pixel circuits further includes a holding capacitor connected between the gate and the source of said driving transistor.
7 . The display apparatus according to claim 6 , wherein, when the light detection operation is carried out by the pixel circuit, said displaying driving section executes a threshold value correction operation of holding a threshold value voltage of said driving transistor into said holding capacitor.
8 . The display apparatus according to claim 1 , wherein each of said pixel circuits further includes a light detection element connected to a fixed power supply and to the gate of said driving transistor through a second switching transistor; and
as the light detection operation, said light detection element applies, when said second switching transistor is placed in an on state, current in accordance with the received light amount to the gate of said driving transistor thereby to vary the gate potential of said driving transistor in response to the received light amount.
9 . The display apparatus according to claim 8 , wherein said light detection element is configured from a transistor connected in diode connection.
10 . The display apparatus according to claim 8 , wherein said light detection element receives light from the outside.
11 . The display apparatus according to claim 1 , wherein said displaying driving section carries out correction of the signal value in response to the light amount information detected by said light amount information detection section.
12 . A light detection method for a display apparatus which includes a plurality of pixel circuits disposed in a matrix at positions at which a signal line and a plurality of scanning lines cross with each other, a displaying driving section adapted to apply a signal value to each of the pixel circuits through the signal line and drive the scanning lines to cause the pixel circuit to carry out light emission with a luminance in accordance with the signal value to carry out image display, and a light amount information detection section adapted to detect light amount information from an output of each of the pixel circuits to a light detection line disposed for the pixel circuit, each of the pixel circuits including alight emitting element, a driving transistor for carrying out application of current to the light emitting element in response to a signal value voltage inputted thereto, a sampling transistor for inputting, when the sampling transistor is switched on, the signal value from the signal line to the gate of the driving transistor, and a switching transistor connected between an end of the driving transistor and the light detection line, the light detection method comprising the step of:
varying, by means of the pixel circuit, the gate potential of the driving transistor in response to the received light amount and outputting the source potential of the driving transistor in response to the potential variation to the light detection line through the switching transistor, and then detecting, by means of the light amount information detection section, light amount information by voltage detection of the light detection line.
13 . An electronic apparatus, comprising;
a plurality of pixel circuits disposed in a matrix at positions at which a signal line and a plurality of scanning lines cross with each other;
a displaying driving section adapted to apply a signal value to each of said pixel circuits through the signal line and drive the scanning lines to cause the pixel circuit to carry out light emission with a luminance in accordance with the signal value to carry out image display; and
a light amount information detection section adapted to detect light amount information from an output of each of said pixel circuits to a light detection line disposed for the pixel circuit;
each of said pixel circuits including
a light emitting element,
a driving transistor for carrying out application of current to said light emitting element in response to a signal value voltage inputted thereto,
a sampling transistor for inputting, when said sampling transistor is switched on, the signal value from the signal line to the gate of said driving transistor, and
a switching transistor connected between an end of said driving transistor and the light detection line;
each of said pixel circuits being capable of executing light detection operation of varying the gate potential of said driving transistor in response to a received light amount and outputting the source potential of said driving transistor in accordance with the potential variation to the light detection line through said switching transistor.
14 . A display apparatus, comprising:
a plurality of pixel circuits disposed in a matrix;
a signal line; and
a light detection line;
each of said pixel circuits including
a light emitting element,
a driving transistor for carrying out current application to said light emitting element,
a sampling transistor for inputting a signal value from said signal line to the gate of said driving transistor, and
a switching transistor connected between an end of said driving transistor and said light detection line;
the gate potential of said driving transistor being varied in response to a received light amount to output a potential at the one end of the driving transistor to said light detection line through said switching transistor.
15 . The display apparatus according to claim 14 , wherein the gate potential of said driving transistor is varied in response to the received light amount with leak current generated in said sampling transistor.
16 . The display apparatus according to claim 14 , further comprising:
a light detection element connected to a fixed power supply;
said light detection element applying current in response to the received light amount to the gate of said driving transistor to vary the gate potential of said driving transistor.
17 . The display apparatus according to claim 16 , wherein said light detection element is configured from a transistor connected in diode connection.