Display apparatus, display-apparatus driving method and electronic instrument

• US 20090278834A1
• Filed: 04/08/2009
• Published: 11/12/2009
• Est. Priority Date: 05/08/2008
• Status: Active Grant

• Current Assignee: JDI Design and Development GK
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Tomida, Masatsugu, Asano, Mitsuru
• Granted Patent: US 8,300,038 B2
• Time in Patent Office: Days
• US Class Current: 345/211
• CPC Class Codes: G09G 2300/0465 Improved aperture ratio, e.g. by size reduction of the pixel circuit, e.g. for improving the pixel density or the maximum displayable luminance or brightness
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2300/0866 by means of changes in the pixel supply voltage
• 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 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 2330/02 Details of power systems and of start or stop of display operation
• CPC Class Codes: G09G 2330/028 Generation of voltages supplied to electrode drivers in a matrix display other than LCD
• 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 matrix section including pixel circuits laid out to form a pixel matrix to serve as pixel circuits each having an electro optical device, a signal writing transistor, a signal storage capacitor, and a device driving transistor, and a power-supply section configured to change a power-supply electric potential appearing on a power-supply line for providing a driving current flowing to the device driving transistor from one level to another in order to control transitions from a light emission period of the electro optical device to a no-light emission period of the electro optical device and vice versa, and stopping an operation to assert the power-supply electric potential on the power-supply line during a portion of the no-light emission period of the electro optical device.

Claims

1. A display apparatus comprising:

a pixel matrix section including pixel circuits laid out to form a pixel matrix to serve as pixel circuits each having

an electro optical device,

a signal writing transistor for writing a video signal,

a signal storage capacitor for holding said video signal written by said signal writing transistor into said signal storage capacitor, and

a device driving transistor for driving said electro optical device in accordance with said video signal held by said signal storage capacitor, and

a power-supply section configured to

change a power-supply electric potential appearing on a power-supply line for providing a driving current flowing to said device driving transistor from one level to another in order to control transitions from a light emission period of said electro optical device to a no-light emission period of said electro optical device and vice versa, and

set a power-supply electric potential appearing on the power-supply line at an electric potential appearing on the cathode electrode of the electro optical device during a portion of said no-light emission period of said electro optical device.

2. The display apparatus according to claim 1 wherein said power-supply section stops said operation to assert said power-supply electric potential on said power-supply line during said portion ending at the start of an operation to initialize an electric potential appearing on a specific electrode which pertains to said device driving transistor and is placed on a side opposite to said power-supply line with respect to said device driving transistor.

3. The display apparatus according to claim 2 wherein:

in said operation to initialize an electric potential appearing on said specific electrode of said device driving transistor, said power-supply section sets said power-supply electric potential at a level causing a reversed bias to be applied to said electro optical device, and

in said light emission period of said electro optical device, said power-supply section sets said power-supply electric potential at another level causing a forward bias to be applied to said electro optical device.

4. The display apparatus according to claim 3 wherein said power-supply section controls a ratio of said light emission period of said electro optical device to said no-light emission period of said electro optical device by adjusting the length of said light emission period used as a period during which said power-supply section is applying said forward bias to said electro optical device.

5. A driving method provided for a display apparatus including

pixel circuits laid out to form a pixel matrix to serve as pixel circuits each having

an electro optical device,

a signal writing transistor for writing a video signal,

a signal storage capacitor for holding said video signal written by said signal writing transistor into said signal storage capacitor, and

a device driving transistor for driving said electro optical device in accordance with said video signal held by said signal storage capacitor,

said driving method including the steps of

changing a power-supply electric potential appearing on a power-supply line for providing a driving current flowing to said device driving transistor from one level to another in order to control transitions from a light emission period of said electro optical device to a no-light emission period of said electro optical device and vice versa, and

setting a power-supply electric potential appearing on the power-supply line at an electric potential appearing on the cathode electrode of the electro optical device during a portion of said no-light emission period of said electro optical device.

6. An electronic instrument employing a display apparatus comprising:

a pixel matrix section including pixel circuits laid out to form a pixel matrix to serve as pixel circuits each having

an electro optical device,

a signal writing transistor for writing a video signal into a signal storage capacitor,

said signal storage capacitor for holding said video signal written by said signal writing transistor into said signal storage capacitor, and

a device driving transistor for driving said electro optical device in accordance with said video signal held by said signal storage capacitor, and

a power-supply section configured to

change a power-supply electric potential appearing on a power-supply line for providing a driving current flowing to said device driving transistor from one level to another in order to control transitions from a light emission period of said electro optical device to a no-light emission period of said electro optical device and vice versa, and

set a power-supply electric potential appearing on the power-supply line at an electric potential appearing on the cathode electrode of the electro optical device during a portion of said no-light emission period of said electro optical device.

7. A display apparatus comprising:

pixel matrix means including pixel circuits laid out to form a pixel matrix to serve as pixel circuits each having

an electro optical device,

a signal writing transistor for writing a video signal,

a signal storage capacitor for holding said video signal written by said signal writing transistor into said signal storage capacitor, and

a device driving transistor for driving said electro optical device in accordance with said video signal held by said signal storage capacitor, and

power-supply means for

changing a power-supply electric potential appearing on a power-supply line for providing a driving current flowing to said device driving transistor from one level to another in order to control transitions from a light emission period of said electro optical device to a no-light emission period of said electro optical device and vice versa, and

setting a power-supply electric potential appearing on the power-supply line at an electric potential appearing on the cathode electrode of the electro optical device during a portion of said no-light emission period of said electro optical device.