Backlight unit and display apparatus having the same

• US 20070081321A1
• Filed: 10/10/2005
• Published: 04/12/2007
• Est. Priority Date: 10/10/2005
• Status: Abandoned Application

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Dong-Ho, Kim, Do-Hyung, Ahn, Seung-Ho
• Application Number:
  US11/247,882
• Publication Number:
  US 20070081321A1
• Time in Patent Office: Days
• US Class Current: 362/97.300
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133604 with lamps
• CPC Class Codes: G02F 1/133609 including means for improving the color mixing, e.g. white
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side

Abstract

In a backlight unit and a display apparatus having the backlight unit, the backlight unit includes a first light source, a second light source, and an optical plate having a lower surface facing the second light source and an upper surface substantially parallel with the lower surface. The first light source generating a first light having a first wavelength range. The second light source generating a second light having a second wavelength range different from the first wavelength range to compensate the first light. Thus, display quality of display apparatus may be improved.

Claims

1. A backlight unit comprising:

a first light source generating a first light having a first wavelength range;

a second light source generating a second light having a second wavelength range different from the first wavelength range; and

an optical plate having a lower surface facing the second light source, an upper surface substantially parallel with the lower surface, and a side surface to connect the lower surface with the upper surface.

2. The backlight unit of claim 1, wherein the second wavelength range is within the first wavelength range.

3. The backlight unit of claim 1, further comprising a reflecting plate disposed under the optical plate, the reflecting plate reflecting a portion of the first and the second light toward the upper surface of the optical plate.

4. The backlight unit of claim 1, wherein the first light source is disposed adjacent to the side surface of the optical plate.

5. The backlight unit of claim 1, wherein the first light source is disposed under the optical plate.

6. The backlight unit of claim 5, wherein the first light source comprises a plurality of fluorescent lamps disposed substantially parallel with each other, and the second light source is disposed between the fluorescent lamps.

7. The backlight unit of claim 1, wherein the second light source is disposed under the optical plate in a matrix shape.

8. The backlight unit of claim 1, wherein the first light source comprises at least one fluorescent lamp.

9. The backlight unit of claim 1, wherein the second light source comprises at least one organic electro luminescent device.

10. The backlight unit of claim 1, wherein the second light source comprises at least one light emitting diode.

11. The backlight unit of claim 1, wherein the first light emitted from the first light source comprises a white light having a red light, a green light, and a blue light, and the second light emitted from the second light source comprises one of the red light, the green light, and the blue light.

12. The backlight unit of claim 1, wherein the second light source includes:

a first electrode receiving a first voltage;

a second electrode receiving a second voltage; and

a luminescent layer disposed between the first and second electrodes,

wherein an electric field is formed in response to the first and second voltages applied to the first and second electrodes to generate the second light.

13. The backlight unit of claim 12, wherein the luminescent layer includes an organic layer having at least one of red color, green color, and blue color.

14. The backlight unit of claim 12, wherein the first electrode includes metal material having a low work function.

15. The backlight unit of claim 14, wherein the second electrode includes transparent conductive material.

16. A display apparatus comprising:

a backlight unit comprising;

a first light source generating a first light having a first wavelength range;

a second light source generating a second light having a second wavelength range different from the first wavelength range; and

an optical plate having a lower surface facing the second light source, an upper surface substantially parallel with the lower surface, and a side surface to connect the lower surface with the upper surface, and

a display panel displaying images using the first and second lights generated by the backlight unit.

17. The display apparatus of claim 16, wherein the backlight unit further comprises a reflecting plate disposed under the optical plate, the reflecting plate reflecting a portion of the first and the second light toward the upper surface of the optical plate.

18. The display apparatus of claim 16, wherein the first light source comprises at least one fluorescent lamp.

19. The display apparatus of claim 16, wherein the second light source comprises at least one organic electro luminescent device.

20. The display apparatus of claim 16, wherein the second light source comprises at least one light emitting diode.

21. The display apparatus of claim 16, wherein the first light emitted from the first light source comprises a white light having a red light, a green light, and a blue light, and the second light comprises one of the red light, the green light, and the blue light.

22. The display apparatus of claim 21, wherein the display panel comprises:

a red color pixel to transmit the red light;

a green color pixel to transmit the green light; and

a blue color pixel to transmit the blue light.

23. A display apparatus comprising:

a first driving unit generating a first driving signal and a control signal in response to an external signal;

a display unit displaying images in response to the first driving signal, the display unit having a plurality of color areas;

a second driving unit generating a second driving signal in response to the control signal from the first driving unit; and

a backlight unit providing the color areas of the display unit with lights having wavelength ranges different from each other, the backlight unit having a plurality of luminescent groups corresponding to the color areas.

24. The display apparatus of claim 23, wherein each of the luminescent groups comprises a plurality of red organic electro luminescent devices, a plurality of green organic electro luminescent devices, and a plurality of blue organic electro luminescent devices, and electric currents different from each other are applied to the red, green, and blue organic electro luminescent devices, respectively.

25. The display apparatus of claim 24, wherein red, green, and blue organic electro luminescent devices of a luminescent group include first, second, and third electrodes, respectively, receiving the electric currents, the first, second, and third electrodes being electrically insulated from each other.

26. The display apparatus of claim 23, wherein each of the luminescent groups comprises a plurality of red organic electro luminescent devices, a plurality of green organic electro luminescent devices, and a plurality of blue organic electro luminescent devices,

a same electric current is applied to the red, green, and blue organic electro luminescent devices, and

color expressions of the red, green, and blue organic electro luminescent devices are different from each other.

27. The display apparatus of claim 26, wherein the red, green, and blue organic electro luminescent devices of a luminescent group include first, second, and third electrodes, respectively, receiving the same electric current, the first, second, and third electrodes being electrically connected to each other.

28. The display apparatus of claim 23, wherein each of the luminescent groups comprises a plurality of red light emitting diodes, a plurality of green light emitting diodes, and a plurality of blue light emitting diodes, and electric currents different from each other are applied to the red, green, and blue light emitting diodes, respectively.

29. The display apparatus of claim 23, wherein each of the luminescent groups comprises a plurality of red light emitting diodes, a plurality of green light emitting diodes, and a plurality of blue light emitting diodes,

a same electric current is applied to the red, green, and blue light emitting diodes, and

color expressions of the red, green, and blue light emitting diodes are different from one another.