Display apparatus and drive method thereof and electronic device

• US 20080231625A1
• Filed: 03/14/2008
• Published: 09/25/2008
• Est. Priority Date: 03/22/2007
• Status: Active Grant

• Current Assignee: JOLED Inc.
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Tomida, Masatsugu, Uchino, Katsuhide, Iida, Yukihito, Minami, Tetsuo
• Granted Patent: US 8,836,690 B2
• Time in Patent Office: Days
• US Class Current: 345/212
• CPC Class Codes: G09G 2300/0819 used for counteracting undesired variations, e.g. feedback or autozeroing
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2310/0256 with the purpose of reversing the voltage across a light emitting or modulating element within a pixel
• CPC Class Codes: G09G 2310/0297 Special arrangements with multiplexing or demultiplexing of display data in the drivers for data electrodes, in a pre-processing circuitry delivering display data to said drivers or in the matrix panel, e.g. multiplexing plural data signals to one D/A converter or demultiplexing the D/A converter output to multiple columns
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element

Abstract

Disclosed herein is a display apparatus including a pixel array section and a drive section. The pixel array section has power supply lines, scan lines arranged in row, signal lines arranged in column, and pixels arranged in matrix at intersections of each of the scan lines and each of the signal lines. The drive transistor is connected at one of a pair of current terminals to the light emitting device and at the other of the pair of current terminals to the power supply line. The drive section supplies a control signal to each scan line and a video signal to each signal line to drive each pixel, executing a threshold voltage correcting operation, a write operation, and a light emitting operation.

Claims

1. A display apparatus comprising:

a pixel array section and a drive section,

said pixel array section having power supply lines, scan lines arranged in row, signal lines arranged in column, and pixels arranged in matrix at intersections of each of said scan lines and each of said signal lines,

each of said pixels at least having a sampling transistor, a drive transistor, a light emitting device, and a capacitor,

said sampling transistor is connected at a control terminal to said scan line and at one of a pair of current terminals of said sampling transistor to said scan line and at the other of said pair of current terminals to a control terminal of said drive transistor,

said drive transistor is connected at one of a pair of current terminals to said light emitting device and at the other of said pair of current terminals to the power supply line,

said drive section supplying a control signal to each scan line and a video signal to each signal line to drive each pixel, executing a threshold voltage correcting operation for correcting a fluctuation of a threshold voltage of said drive transistor, a write operation for writing said video signal to said capacitor, and a light emitting operation for driving said light emitting device in accordance with the written video signal,

said threshold voltage correcting operation having a preparation process in which, while the control terminal that is a gate of said drive transistor is maintained at a reference potential, a gate-to-source voltage with the current terminal that is a source of said drive transistor is set higher than said threshold voltage to turn on said drive transistor,

an energizing process in which said drive transistor is energized with said gate maintained at the reference potential to hold, in said capacitor, a voltage equivalent to said threshold voltage appearing between said gate and said source when said drive transistor is cut off, and

a compression process in which said reference potential applied to said gate is varied to compress said gate-to-source voltage to higher level than the voltage equivalent to said threshold voltage to surely turn off said drive transistor.

2. The display apparatus according to claim 1, wherein said drive section has a write scanner for sequentially supplying control signals to scan lines for each horizontal scan period, a power supply scanner for switching each power supply line between high potential and low potential, and a signal driver for supplying a video signal in which a signal potential and a reference potential are switched in each horizontal scan period to each signal line;

in said preparation period, while said write scanner outputs a control signal to turn on said sampling transistor and samples the reference potential from the signal line to apply the sampled reference potential to the gate of said drive transistor, said power supply scanner switches said power supply line from high potential to low potential to lower a potential of the source of said drive transistor to low potential;

in said energizing process, said power supply scanner switches said power supply line from low potential to high potential to energize said drive transistor until said drive transistor cuts off; and

in said compression process, said signal driver switches a level of said reference potential downward immediately before said write scanner clears the control signal to turn off said sampling transistor while said power supply scanner maintains said power supply line at high potential.

8. An electronic device, comprising

a display apparatus according to claim 1.

3. A display apparatus comprising:

a pixel array section and a drive section,

said pixel array section having power supply lines, scan lines arranged in row, signal lines arranged in column, and pixels arranged in matrix at intersections of each of said scan lines and each of said signal lines,

each of said pixels at least having a sampling transistor, a drive transistor, a light emitting device, and a capacitor,

said sampling transistor is connected at a control terminal to said scan line and at one of a pair of current terminals of said sampling transistor to said scan line and at the other of said pair of current terminals to a control terminal of said drive transistor,

said drive transistor is connected at one of a pair of current terminals to said light emitting device and at the other of said pair of current terminals to the power supply line,

said drive section supplying a control signal to each scan line and a video signal to each signal line to drive each pixel, executing a threshold voltage correcting operation for correcting a fluctuation of a threshold voltage of said drive transistor, a write operation for writing said video signal to said capacitor, and a light emitting operation for emitting said light emitting device in accordance with the written video signal,

said threshold voltage correcting operation having a preparation process in which, while the control terminal that is a gate of said drive transistor is maintained at a reference potential, a gate-to-source voltage with the current terminal that is a source of said drive transistor is set higher than said threshold voltage to turn on said drive transistor and

an energizing process in which said drive transistor is energized with said gate maintained at the reference potential to hold, in said capacitor, a voltage equivalent to said threshold voltage appearing between said gate and said source when said drive transistor is cut off,

said energizing process being executed in a time division manner a plurality of times until said drive transistor cuts off, there being a difference between a reference potential to be applied to the gate of said drive transistor in a preceding energizing process and a reference potential to be applied to the gate of said drive transistor in a following energizing process.

4. The display apparatus according to claim 3, wherein said energizing process is executed in a time division manner a plurality of times until said drive transistor cuts off and the reference potential to be applied to the gate of said drive transistor in the following energizing process becomes higher than the reference potential to be applied to the gate of said drive transistor in the preceding energizing process.

5. The display apparatus according to claim 4, wherein said drive section has a write scanner for sequentially supplying control signals to scan lines for each horizontal scan period, a power supply scanner for switching each power supply line between high potential and low potential, and a signal driver for supplying a video signal in which a signal potential and a reference potential are switched in each horizontal scan period to each signal line;

in said preparation period, while said write scanner outputs a control signal to turn on said sampling transistor and samples the reference potential from the signal line to apply the sampled reference potential to the gate of said drive transistor, said power supply scanner switches said power supply line from high potential to low potential to lower a potential of the source of said drive transistor to low potential; and

in said energizing process, said power supply scanner switches said power supply line from low potential to high potential to energize said drive transistor until said drive transistor cuts off,

wherein said signal driver executes switching control such that the reference potential to be outputted to the signal line in the following energizing processing is higher than the reference potential to be outputted to the signal line in the preceding energizing process.

9. An electronic device, comprising

a display apparatus according to claim 3.

6. A driving method for a display apparatus made up of a pixel array section and a drive section,

said pixel array section having power supply lines, scan lines arranged in row, signal lines arranged in column, and pixels arranged in matrix at intersections of each of said scan lines and each of said signal lines,

each of said pixels at least having a sampling transistor, a drive transistor, a light emitting device, and a capacitor,

said sampling transistor is connected at a control terminal of the sampling transistor to said scan line and at one of a pair of current terminals of said sampling transistor to said signal line and at the other of said pair of current terminals to a control terminal of said drive transistor,

said drive transistor is connected at one of a pair of current terminals to said light emitting device and at the other of said pair of current terminals to the power supply line,

said drive section supplying a control signal to each scan line and a video signal to each signal line to drive each pixel, executing a threshold voltage correcting operation for correcting a fluctuation of a threshold voltage of said drive transistor, a write operation for writing said video signal to said capacitor, and a light emitting operation for emitting said light emitting device in accordance with the written video signal, said driving method comprising the steps of:

setting a gate-to-source voltage with the current terminal that is a source of said drive transistor is set higher than said threshold voltage to turn on said drive transistor while the control terminal that is a gate of said drive transistor is maintained at a reference potential;

energizing said drive transistor with said gate maintained at the reference potential to hold, in said capacitor, a voltage equivalent to said threshold voltage appearing between said gate and said source when said drive transistor is cut off; and

varying said reference potential applied to said gate to compress said gate-to-source voltage to higher level than the voltage equivalent to said threshold voltage to surely turn off said drive transistor.

7. A driving method for a display apparatus made up of a pixel array section and a drive section,

said pixel array section having power supply lines, scan lines arranged in row, signal lines arranged in column, and pixels arranged in matrix at intersections of each of said scan lines and each of said signal lines,

each of said pixels at least having a sampling transistor, a drive transistor, a light emitting device, and a capacitor,

said sampling transistor is connected at a control terminal of the sampling transistor to said scan line and at one of a pair of current terminals of said sampling transistor to said signal line and at the other of said pair of current terminals to a control terminal of said drive transistor,

said drive transistor is connected at one of a pair of current terminals to said light emitting device and at the other of said pair of current terminals to the power supply line,

said drive section supplying a control signal to each scan line and a video signal to each signal line to drive each pixel, executing a threshold voltage correcting operation for correcting a fluctuation of a threshold voltage of said drive transistor, a write operation for writing said video signal to said capacitor, and a light emitting operation for emitting said light emitting device in accordance with the written video signal, said driving method comprising the steps of:

setting a gate-to-source voltage with the current terminal that is a source of said drive transistor is set higher than said threshold voltage to turn on said drive transistor while the control terminal that is a gate of said drive transistor is maintained at a reference potential; and

energizing said drive transistor with said gate maintained at the reference potential to hold, in said capacitor, a voltage equivalent to said threshold voltage appearing between said gate and said source when said drive transistor is cut off,

said energizing process being executed in a time division manner a plurality of times until said drive transistor cuts off, there being a difference between a reference potential to be applied to the gate of said drive transistor in a preceding energizing process and a reference potential to be applied to the gate of said drive transistor in a following energizing process.

10. A display apparatus comprising:

pixel array means and drive means,

said pixel array means having power supply lines, scan lines arranged in row, signal lines arranged in column, and pixels arranged in matrix at intersections of each of said scan lines and each of said signal lines,

each of said pixels at least having a sampling transistor, a drive transistor, a light emitting device, and a capacitor,

said sampling transistor is connected at a control terminal to said scan line and at one of a pair of current terminals of said sampling transistor to said scan line and at the other of said pair of current terminals to a control terminal of said drive transistor,

said drive transistor is connected at one of a pair of current terminals to said light emitting device and at the other of said pair of current terminals to the power supply line,

said drive means supplying a control signal to each scan line and a video signal to each signal line to drive each pixel, executing a threshold voltage correcting operation for correcting a fluctuation of a threshold voltage of said drive transistor, a write operation for writing said video signal to said capacitor, and a light emitting operation for driving said light emitting device in accordance with the written video signal,

said threshold voltage correcting operation having a preparation process in which, while the control terminal that is a gate of said drive transistor is maintained at a reference potential, a gate-to-source voltage with the current terminal that is a source of said drive transistor is set higher than said threshold voltage to turn on said drive transistor,

an energizing process in which said drive transistor is energized with said gate maintained at the reference potential to hold, in said capacitor, a voltage equivalent to said threshold voltage appearing between said gate and said source when said drive transistor is cut off, and

a compression process in which said reference potential applied to said gate is varied to compress said gate-to-source voltage to higher level than the voltage equivalent to said threshold voltage to surely turn off said drive transistor.

11. A display apparatus comprising:

pixel array means and drive means,

said pixel array means having power supply lines, scan lines arranged in row, signal lines arranged in column, and pixels arranged in matrix at intersections of each of said scan lines and each of said signal lines,

each of said pixels at least having a sampling transistor, a drive transistor, a light emitting device, and a capacitor,

said sampling transistor is connected at a control terminal to said scan line and at one of a pair of current terminals of said sampling transistor to said scan line and at the other of said pair of current terminals to a control terminal of said drive transistor,

said drive transistor is connected at one of a pair of current terminals to said light emitting device and at the other of said pair of current terminals to the power supply line,

said drive means supplying a control signal to each scan line and a video signal to each signal line to drive each pixel, executing a threshold voltage correcting operation for correcting a fluctuation of a threshold voltage of said drive transistor, a write operation for writing said video signal to said capacitor, and a light emitting operation for emitting said light emitting device in accordance with the written video signal,

said threshold voltage correcting operation having a preparation process in which, while the control terminal that is a gate of said drive transistor is maintained at a reference potential, a gate-to-source voltage with the current terminal that is a source of said drive transistor is set higher than said threshold voltage to turn on said drive transistor and

an energizing process in which said drive transistor is energized with said gate maintained at the reference potential to hold, in said capacitor, a voltage equivalent to said threshold voltage appearing between said gate and said source when said drive transistor is cut off,

said energizing process being executed in a time division manner a plurality of times until said drive transistor cuts off, there being a difference between a reference potential to be applied to the gate of said drive transistor in a preceding energizing process and a reference potential to be applied to the gate of said drive transistor in a following energizing process.