Method for driving a light source and light source apparatus for performing the method

• US 8,692,759 B2
• Filed: 06/11/2009
• Issued: 04/08/2014
• Est. Priority Date: 01/06/2009
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Park, Se-Ki, Yeo, Dong-Min, Kim, Gi-Cherl, Song, Si-Joon, Cho, Chi-O, Lee, Young-Keun
• Primary Examiner(s): Wang, Claire X
• Assistant Examiner(s): STONE, ROBERT M
• Application Number:
  US12/482,959
• Publication Number:
  US 20100171690A1
• Time in Patent Office: 1,762 Days
• Field of Search: 345/102
• US Class Current: 345/102
• CPC Class Codes: G09G 2320/0285 using tables for spatial correction of display data
• CPC Class Codes: G09G 2320/064 by time modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix

Abstract

A light source apparatus includes light-emitting blocks, a local dimming control part and a light source driving part driving. The light-emitting blocks include a first-color light source which emits first-color light and a second-color light source which emits second-color light. The second-color light source includes a third-color chip and a fourth-color phosphor disposed on the third-color chip, and is disposed as one package to emit the second-color light therefrom. The local dimming control part compensates a driving current of the first-color light source and a driving current of the second-color light source of each of the light-emitting blocks. The light source driving part drives the first-color light source and the second-color light sources based on the driving current of the first-color light source and the a driving current of the second-color light source, respectively, each compensated by the local dimming control part.

Claims

1. A method for driving a light source, the light source comprising light-emitting blocks, each of the light-emitting blocks including a first-color light source which emits first-color light and a second-color light source which emits second-color light, the second-color light source comprising a third-color chip and a fourth-color phosphor disposed on the third-color chip, the third color chip and the fourth-color phosphor disposed as one package to emit the second-color light therefrom, the method comprising:

compensating a driving current of the first-color light source and a driving current of the second-color light source of each of the light-emitting blocks based on image signal data corresponding to each of the light-emitting blocks, respectively, to generate a compensated driving current of the first-color light source and a compensated driving current of the second-color light source; and

driving the first-color light source and the second-color light source based on the compensated driving current of the first-color light source and the compensated driving current of the second-color light source, respectively,

wherein the compensating the driving current of the first-color light source and the driving current of the second-color light source comprises;

determining a duty of the driving current of the first-color light source and a duty of the driving current of the second-color light source using image data corresponding to each of the light-emitting blocks;

determining a driving mode of each of the light-emitting blocks based on the duty of the driving current of the first-color light source and the duty of the driving current of the second-color light source; and

compensating the driving current of the first-color light source and the driving current of the second-color light source based on the driving mode, and

wherein the determining the duty of the driving current of the second-color light source comprises;

generating representative data by sampling a larger one of third-color and fourth-color data of the image data; and

determining the duty of the driving current of the second-color light source based on the representative data.

2. The method of claim 1, wherein the compensating the driving current of the first-color light source and the second-color light source comprises time-filtering the duty of the driving current of the first-color light source and the duty of the driving current of the second-color light source when a corresponding light-emitting block operates in a normal mode.

3. The method of claim 1, wherein the compensating the driving current of the first-color light source and the driving current of the second-color light source comprises compensating at least one of the duty and a level of at least one of the driving current of the first-color light source and the driving current of the second-color light source when a corresponding light-emitting block operates in a boost mode.

4. The method of claim 3, wherein the compensating the at least one of the duty and the level of the at least one of the driving current of the first-color light source and the driving current of the second-color light source comprises compensating the duty of the driving current of the first-color light source when the level of the driving current of the first-color light sources is maximum and compensating the level of the driving current of the second-color light source when the duty of the driving current of the second-color light source is maximum, such that the compensating the duty of the driving current of the first-color light source and the compensating the level of the driving current of the second-color light source correspond to target color coordinates and target luminance.

5. The method of claim 3, wherein the compensating the at least one of the duty and the level of the at least one of the driving current of the first-color light source and the driving current of the second-color light source comprises using a lookup table which stores a pair comprising the duty of the driving current of the first-color light source and the level of the driving current of the second-color light source corresponding to target color coordinates and target luminance.

6. The method of claim 5, wherein the compensating the at least one of the duty and the level of the at least one of the driving current of the first-color light source and the driving current of the second-color light source further comprises additionally compensating the duty of the driving current of the second-color light source when the level of the driving current of the second-color light sources is greater than a predetermined value.

7. The method of claim 1, wherein the first-color light source comprises a green light-emitting diode, and the second-color light source comprises a magenta light-emitting diode which includes a blue chip and a red phosphor disposed on the blue chip.

8. The method of claim 1, wherein the first-color light source comprises a red light-emitting diode, and the second-color light source comprises a cyan light-emitting diode which includes a blue chip and a green phosphor disposed on the blue chip.

9. The method of claim 1, wherein the fourth-color phosphor only covers the second light source of the light emitting group.

10. A light source apparatus comprising:

light-emitting blocks, each including a first-color light source which emits first-color light and a second-color light source which emits second-color light, the second-color light source comprising a third-color chip and a fourth-color phosphor disposed on the third-color chip, the third color chip and the fourth-color phosphor disposed as one package to emit the second-color light therefrom;

a local dimming control part which compensates a driving current of the first-color light source and a driving current of the second-color light source of each of the light-emitting blocks based on image signal data corresponding to each of the light-emitting blocks, respectively, and the local dimming control part comprising;

a duty determining part which determines a duty of the driving current of the first-color light source and a duty of the driving current of the second-color light source using image data corresponding to each of the light-emitting blocks;

a driving mode determining part which determines a driving mode of the light-emitting blocks based on the duty of the driving current of the first-color light source and the duty of the driving current of the second-color light source; and

a compensating part which compensates the driving current of the first-color light source and the driving current of the second-color light source based on the driving mode; and

a light source driving part which drives the first-color light source and the second-color light source based on the driving current of the first-color light source and the driving current of the second-color light source, respectively, each compensated by the local dimming control part,

wherein the duty determining part generates representative data by sampling a larger one of third-color and fourth-color data of the image data and determines the duty of the driving current of the second-color light source based on the representative data.

11. The light source apparatus of claim 10, wherein

the compensating part time-filters the duty of the driving current of the first-color light source and the duty of the driving current of the second-color light source when the light-emitting block operates in a normal mode, and

the compensating part compensates at least one of the duty and a level of at least one of the driving current of the first-color light source and the driving current of the second-color light source when the light-emitting block operates in a boost mode.

12. The light source apparatus of claim 11, wherein the compensating part compensates the duty of the driving current of the first-color light source when the level of the driving current of the first-color light sources is maximum and compensates the level of the driving current of the second-color light source when the duty of the driving current of the second-color light sources is maximum, such that the duty of the driving current of the first-color light source and the level of the driving current of the second-color light source correspond to target color coordinates and target luminance when the corresponding light-emitting block operates in the boost mode.

13. The light source apparatus of claim 12, wherein the compensating part uses a lookup table which stores a pair, the pair including the duty of the driving current of the first-color light source and the level of the driving current of the second-color light source corresponding to the target color coordinates and the target luminance.

14. The light source apparatus of claim 10, wherein

the first-color light source comprises a red light-emitting diode, and

the second-color light source comprises a cyan light-emitting diode which includes a blue chip and a green phosphor disposed on the blue chip.

15. The light source apparatus of claim 10, wherein

the first-color light source comprises a green light-emitting diode, and

the second-color light source comprises a magenta light-emitting diode which includes a blue chip and a red phosphor disposed on the blue chip.

16. The light source apparatus of claim 10, wherein

the first-color light source and the second-color light source include at least one red chip, at least one blue chip and a green phosphor disposed on the at least one red chip and the at least one blue chip, and

the first-color light source and the second-color light source are integrally disposed together as a light-emitting diode.

17. The light source apparatus of claim 10, wherein the third-color chip includes a plurality of color chips.

18. The light source apparatus of claim 10, wherein the fourth-color phosphor is mixed with one of a silicone resin and an epoxy resin.

19. The light source apparatus of claim 10, wherein the fourth-color phosphor only covers the second light source of the light emitting group.