El display and its driving method

• US 20070080905A1
• Filed: 04/28/2004
• Published: 04/12/2007
• Est. Priority Date: 05/07/2003
• Status: Abandoned Application

• Current Assignee: Toshiba Matsushita Display Technology (Japan Display Incorporated)
• Original Assignee: Toshiba Matsushita Display Technology (Japan Display Incorporated)
• Inventors: Takahara, Hiroshi
• Application Number:
  US10/555,460
• Publication Number:
  US 20070080905A1
• Time in Patent Office: Days
• US Class Current: 345/76
• CPC Class Codes: G09G 2300/043 Compensation electrodes or other additional electrodes in matrix displays related to distortions or compensation signals, e.g. for modifying TFT threshold voltage in column driver
• CPC Class Codes: G09G 2300/0861 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 Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 3/3241 the current through the light-emitting element being set using a data current provided by the data driver, e.g. by using a two-transistor current mirror
• CPC Class Codes: G09G 3/3258 with pixel circuitry controlling the voltage across the light-emitting element

Abstract

It is difficult to obtain a good image display by using an organic EL display panel.

An EL display apparatus includes EL elements 15 and driving transistors 11a placed like a matrix, a voltage gradation circuit 1271 for generating a program voltage signal, a current gradation circuit 164 for generating a program current signal, and a drive circuit means of applying a signal to the driving transistors 11a, having switches 151a and 151b for switching between the program voltage signal and the program current signal.

Claims

1. An EL display apparatus comprising:

EL elements and drive elements placed like a matrix;

a voltage gradation circuit for generating a program voltage signal;

current circuit means of generating a program current signal; and

a drive circuit means of applying a signal to the drive elements, having a switching circuit for switching between the program voltage signal and the program current signal.

2. A driving method of an EL display apparatus having EL elements and drive elements placed like a matrix formed therein and having a source signal line for stamping a signal to the drive elements, in which:

one horizontal scanning period has a period A for applying a voltage signal to the source signal line and a period B for applying a current signal to the source signal line; and

the period B is started after an end of, or concurrently with the period A.

3. An EL display apparatus comprising:

a first source driver circuit connected to one end of a source signal line; and

a second source driver circuit connected to the other end of the source signal line,

in which the first source driver circuit and the second source driver circuit output currents corresponding to gradations.

4. A driving method of an EL display apparatus having pixels formed like a matrix, in which:

a lighting rate is acquired from a size of a video signal applied to the EL display apparatus so as to control a flowing current correspondingly to the lighting rate.

5. An EL display apparatus comprising:

a first reference current source for prescribing a size of a first output current to be applied to red pixels;

a second reference current source for prescribing a size of a second output current to be applied to green pixels;

a third reference current source for prescribing a size of a third output current to be applied to blue pixels; and

control means of controlling the first reference current source, the second reference current source and the third reference current source,

in which the control means changes the sizes of the first output current, the second output current and the third output current in proportion.