Display apparatus with function which makes gradiation control easier

• US 20030174152A1
• Filed: 01/30/2003
• Published: 09/18/2003
• Est. Priority Date: 02/04/2002
• Status: Abandoned Application

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Noguchi, Yukihiro
• Application Number:
  US10/354,183
• Publication Number:
  US 20030174152A1
• Time in Patent Office: Days
• US Class Current: 345/690
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• 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 2320/0233 Improving the luminance or brightness uniformity across the screen
• 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 3/3283 in which the data driver supplies a variable data current for setting the current through, or the voltage across, the light-emitting elements
• CPC Class Codes: G09G 3/3291 in which the data driver supplies a variable data voltage for setting the current through, or the voltage across, the light-emitting elements

Abstract

When a data transferring transistor turns on, luminance data being applied to a data line is set in a drive transistor in the form of a data voltage. A current corresponding to the data voltage thus set flows to the drive transistor and simultaneously the same current flows to a first current mirror transistor. Then, a current corresponding to the ratio of a driving capability of a second current mirror transistor to that of the first current mirror transistor flows to the second current mirror transistor.

Claims

1. A display apparatus, including:

an optical element;

a drive circuit which drives said optical element; and

a conversion circuit which converts a driving capability of said drive circuit,

wherein the driving capability which has been converted by said conversion circuit operates on said optical element.

2. A display apparatus according to claim 1, wherein said conversion circuit includes a current mirror circuit, and wherein after a current flowing through said drive circuit is multiplied by a predetermined factor by the current mirror circuit, the current flows to said optical element.

3. A display apparatus according to claim 2, wherein said conversion circuit further includes a shutoff means which substantially shuts off a current flowing to the current mirror circuit, and luminance of said optical element is controlled by controlling the shutoff means.

4. A display apparatus according to claim 1, wherein said conversion circuit includes a current branch circuit which directs part of currents flowing to said drive circuit to said optical element.

6. A display apparatus according to claim 1, wherein said drive circuit includes a thin film transistor.

7. A display apparatus according to claim 2, wherein said drive circuit includes a thin film transistor.

8. A display apparatus according to claim 3, wherein said drive circuit includes a thin film transistor.

9. A display apparatus according to claim 4, wherein said drive circuit includes a thin film transistor.

11. A display apparatus according to claim 1, wherein said optical element is an organic light emitting diode.

12. A display apparatus according to claim 2, wherein said optical element is an organic light emitting diode.

13. A display apparatus according to claim 3, wherein said optical element is an organic light emitting diode.

14. A display apparatus according to claim 4, wherein said optical element is an organic light emitting diode.

16. A display apparatus according to claim 6, wherein said optical element is an organic light emitting diode.

17. A display apparatus according to claim 7, wherein said optical element is an organic light emitting diode.

18. A display apparatus according to claim 8, wherein said optical element is an organic light emitting diode.

19. A display apparatus according to claim 9, wherein said optical element is an organic light emitting diode.

5. A display apparatus which sets luminance data in a driver element by an analog gradation method and which includes a conversion circuit that widens a setting range of the luminance data in the display apparatus that drives an optical element.

10. A display apparatus according to claim 5, wherein said drive circuit includes a thin film transistor.

15. A display apparatus according to claim 5, wherein said optical element is an organic light emitting diode.

20. A display apparatus according to claim 10, wherein said optical element is an organic light emitting diode.