EL display apparatus

Patent metadata

Field	Value
Publication number	US-9922597-B2
Application number	US-201615335932-A
Country	US
Kind code	B2
Filing date	Oct 27, 2016
Priority date	Sep 7, 2001
Publication date	Mar 20, 2018
Grant date	Mar 20, 2018

Abstract

An electroluminescent (EL) display apparatus and corresponding method of control are provided. A display screen includes pixels arranged in a matrix. A pixel circuit of each of the pixels includes, in part: a second switch transistor to supply, to a driving transistor, an image signal; and a third switch transistor for initially resetting the pixel circuit before the second switch transistor supplies the image signal. A gate terminal of the second switch transistor and a gate terminal of the third switch transistor are connected to a second gate driver circuit. The second gate driver circuit includes a first gate driver circuit and a second gate driver circuit. The second gate driver circuit includes a second gate signal line connected to both the gate terminal of the second switch transistor of a Nth row and the gate terminal of the third switch transistor of a (N+1)th row.

First claim

What is claimed is:

1. An electroluminescent (EL) display apparatus comprising:
a display screen including pixels arranged in a matrix, each of the pixels including an EL device and a pixel circuit;
a source signal line through which an analog image signal output from a source driver circuit is transmitted; and
a gate driver circuit which includes a first gate driver circuit and a second gate driver circuit, first gate signal lines through which selection voltages and non-selection voltages output from the first gate driver circuit are transmitted, and second gate signal lines through which selection voltages and non-selection voltages output from the second gate driver circuit are transmitted,
wherein the pixel circuit of each of the pixels includes:
a driving transistor to supply a current to the EL device;
a first switch transistor provided on a current path through which the current is supplied by the driving transistor to the EL device;
a second switch transistor to supply, to the driving transistor, the analog image signal supplied from the source signal line; and
a third switch transistor for initially resetting the pixel circuit before the second switch transistor supplies, to the driving transistor, the analog image signal supplied from the source signal line,

a gate terminal of the first switch transistor is connected to the first gate driver circuit,
a gate terminal of the second switch transistor and a gate terminal of the third switch transistor are connected to the second gate driver circuit,
the second gate driver circuit includes a second gate signal line connected to both the gate terminal of the second switch transistor of a Nth row and the gate terminal of the third switch transistor of a (N+1)th row for simultaneously connecting the gate terminal of the second switch transistor of the Nth row and the gate terminal of the third switch transistor of the (N+1)th row,
the third switch transistor initially resets a gate terminal of the driving transistor by shorting the gate terminal of the driving transistor and an initial reset voltage line, and
the first switch transistor of the (N+1)th row is controlled in an OFF state by the first gate driver circuit when the third switch transistor initially resets the gate terminal of the driving transistor.

2. The EL display apparatus according to claim 1 , further comprising:
a source driver circuit connected to the source signal line,
wherein the source driver circuit is configured to supply a signal voltage to a gate of the driving transistor to flow a current which is N times as large as a predetermined value to the EL device to achieve a gray scale display indicated by the analog image signal, and
N is greater than one.

3. The EL display apparatus according to claim 1 , further comprising:
a precharge circuit or a discharge circuit which forcibly charges or discharges the source signal line.

4. The EL display apparatus according to claim 1 ,
wherein, by the first gate driver circuit and the second gate driver circuit, the first switch transistor is independently on/off controlled from the second switch transistor and the third switch transistor.

5. The EL display apparatus according to claim 1 ,
wherein the first gate driver circuit is configured to select a plurality of the first gate signal lines simultaneously.

6. The EL display apparatus according to claim 1 ,
wherein the third switch transistor initially resets the gate terminal of the driving transistor before the second switch transistor supplies, to the driving transistor, the analog image signal supplied from the source signal line.

7. An electronic device, comprising:
the EL display apparatus according to claim 1 .

8. The EL display apparatus according to claim 1 ,
wherein a single transistor is on a path that supplies the analog image signal (from the source signal line to the driving transistor.

9. The EL display apparatus according to claim 1 ,
wherein a different second gate signal line is simultaneously connected to the gate terminal of the second switch transistor of the (N+1)th row and the gate terminal of the third switch transistor of the (N+2)th row.

10. The EL display apparatus according to claim 1 ,
the first switch transistor of the Nth row is controlled in an OFF state by the first gate driver circuit.

11. The EL display apparatus according to claim 1 ,
the voltage of the initial reset voltage line is a predetermined constant voltage.

12. The EL display apparatus according to claim 1 ,
the first switch transistor, the second switch transistor, and third switch transistor are P channel transistors.

13. The EL display apparatus according to claim 1 ,
the second gate driver circuit connecting the gate terminal of the third switch transistor of the Nth row, and sequentially connecting the gate terminal of the second switch transistor of the Nth row, are synchronized with a 1H synchronization signal.

14. The EL display apparatus according to claim 1 ,
the second gate driver circuit connecting the gate terminal of the third switch transistor of the (N+1)th row, and sequentially connecting the gate terminal of the second switch transistor of the (N+1)th row, are synchronized with a 1H synchronization signal.

15. An electroluminescent (EL) display apparatus, comprising:
a display screen including pixels arranged in a matrix, each of the pixels including an EL device and a pixel circuit;
a source signal line through which an analog image signal output from a source driver circuit is transmitted; and
a gate driver circuit which includes a first gate driver circuit and a second gate driver circuit, first gate signal lines through which selection voltages and non-selection voltages output from the first gate driver circuit are transmitted, and second gate signal lines through which selection voltages and non-selection voltages output from the second gate driver circuit are transmitted,
wherein the pixel circuit of each of the pixels includes:
a driving transistor to supply a current to the EL device;
a first switch transistor provided on a current path through which the current is supplied by the driving transistor to the EL device;
a second switch transistor to supply, to the driving transistor, the analog image signal supplied from the source signal line; and
a third switch transistor for initially resetting the pixel circuit before the second switch transistor supplies, to the driving transistor, the analog image signal supplied from the source signal line,

a gate terminal of the first switch transistor is connected to the first gate driver circuit,
a gate terminal of the second switch transistor and a gate terminal of the third switch transistor are connected to the second gate driver circuit,
the second gate driver circuit includes a second gate signal line connected to both the gate terminal of the second switch transistor of a Nth row and the gate terminal of the third switch transistor of a (N+1)th row for simultaneously connecting the gate terminal of the second switch transistor of the Nth row and the gate terminal of the third switch transistor of the (N+1)th row, and
the third switch transistor initially resets a gate terminal of the driving transistor by shorting the gate terminal of the driving transistor and a drain terminal of the driving transistor.

16. A method of controlling an electroluminescent (EL) display apparatus,
the EL display apparatus comprising:
a display screen including pixels arranged in a matrix, each of the pixels including an EL device and a pixel circuit;
a source signa

Assignees

• Joled Inc

Inventors

• Takahara Hiroshi
• Tsuge Hitoshi

Classifications

• G09G2300/0861

  with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes · CPC title

• G09G2310/027

  Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters · CPC title

• G09G2310/0248

  Precharge or discharge of column electrodes before or after applying exact column voltages · CPC title

• G09G2300/0819

  used for counteracting undesired variations, e.g. feedback or autozeroing · CPC title

• G09G2310/0218

  with collection of electrodes in groups for n-dimensional addressing · CPC title