Backlight for display device, light source for display device, and light emitting diode used therefor

• US 20050286264A1
• Filed: 06/29/2005
• Published: 12/29/2005
• Est. Priority Date: 06/29/2004
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Yoon, Ju-Young, Kim, Gi-Cherl, Kim, Jin-Ha, Lee, Sang-Yu, Song, Chun-Ho, Lee, Jong-Seo, Lee, Sang-Gil, Kang, Seock-Hwan
• Granted Patent: US 7,293,907 B2
• Time in Patent Office: Days
• US Class Current: 362/600
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A light source for a display device includes a board and light emitting diodes mounted on the board. The light emitting diodes include a white light emitting diode which emits white light and a red light emitting diode which emits red light.

Claims

1. A light source for a display device comprising:

a board; and

light emitting diodes (LEDs) mounted on the board,

wherein the LEDs include a white LED which emits white light and a red LED which emits red light.

2. The light source of claim 1, wherein the white LED includes:

an LED chip which emits light having a wavelength range equal to or less than a wavelength of blue light; and

a fluorescent material which converts a wavelength of the light emitted by the LED chip,

wherein the white LED emits light having all of a red component, a green component, and a blue component.

3. The light source of claim 2, wherein the LED chip is disposed at a lead frame and the fluorescent material is covered by a molding element.

4. The light source of claim 1, wherein the white LED includes a blue LED chip and a yellow fluorescent material covering the blue LED chip.

5. The light source of claim 1, wherein the white LED includes an ultraviolet LED chip and a mixture of red fluorescent material, green fluorescent material, and blue fluorescent material covering the ultraviolet LED chip.

6. The light source of claim 1, further comprising white LEDs and red LEDs arranged alternately in a line on the board.

7. The light source of claim 1, further comprising white LEDs arranged on the board to surround the red LED.

8. A light source for a display device comprising:

a board;

a first LED mounted on the board, the first LED including an LED chip and a fluorescent material for converting a wavelength of light emitted from the LED chip; and

a second LED mounted on the board, the second LED including no fluorescent material.

9. The light source of claim 8, wherein the LED chip emits blue light, the fluorescent material is yellow, and the second LED emits red light.

10. The light source of claim 8, wherein the LED chip emits ultraviolet light, the fluorescent material is a mixture of red fluorescent material, green fluorescent material, and blue fluorescent material, and the second LED emits red light.

11. The light source of claim 8, further comprising first LEDs and second LEDs arranged alternately in a line on the board.

12. The light source of claim 8, further comprising first LEDs arranged to surround the second LED.

13. A light source for a display device comprising:

a board;

a first LED mounted on the board and emitting light having a spectrum width which spans a wavelength range below about 600 nm; and

a second LED mounted on the board and emitting light having a spectrum width which spans a wavelength range above about 600 nm.

14. The light source of claim 13, wherein a spectrum of light emitted by the first LED has at least two peaks, and a spectrum of light emitted by the second LED has a peak.

15. The light source of claim 14, wherein the spectrum of the light emitted by the first LED has a peak in a red area, a peak in a green area, and a peak in a blue area.

16. The light source of claim 14, wherein the spectrum of the light emitted from the second LED has the peak in a red area.

17. A light emitting diode (LED) comprising:

a lead frame;

a first LED chip mounted on the lead frame;

a fluorescent material which covers the first LED chip;

a second LED chip mounted on the lead frame; and

a molding element which covers all of the first LED chip, the fluorescent material and the second LED chip.

18. The light emitting diode of claim 17, wherein a number of first LED chips is larger than a number of second LED chips.

19. The light emitting diode of claim 17, wherein the first LED chip emits blue light, the fluorescent material is yellow, and the second LED chip emits red light.

20. The light emitting diode of claim 17, wherein the first LED chip emits ultraviolet light, the fluorescent material is a mixture of red fluorescent material, green fluorescent material, and blue fluorescent material, and the second LED chip emits red light.

21. A backlight device comprising:

a light guiding plate; and

a first light source disposed at a first edge of the light guiding plate and including a white LED emitting white light and a red LED emitting red light.

22. The backlight device of claim 21, wherein the light guiding plate includes grooves and the white LED and the red LED are disposed in the grooves.

23. The backlight device of claim 21 further comprising a second light source disposed at a second edge of the light guiding plate that is opposite to the first edge of the light guiding plate.

24. The backlight device of claim 21, wherein the light guiding plate has a largest thickness at the first edge, and becomes gradually slimmer while extending toward a second edge that is opposite to the first edge.

25. A backlight device comprising:

a board;

a white LED mounted on the board and emitting white light;

a red LED mounted on the board and emitting red light; and

a reflecting plate mounted on the board and including holes for exposing portions of the white LED and the red LED.

26. The backlight device of claim 25, wherein the white LED and the red LED are arranged in a line on the board.

27. The backlight device of claim 26, further comprising a plurality of boards arranged substantially parallel to each other.

28. A light source for a display device comprising:

a board;

a first LED mounted on the board and emitting light having a spectrum width which spans a first wavelength range; and

a second LED mounted on the board and emitting light having a spectrum width which spans a second wavelength range,

wherein the first and second wavelength ranges are substantially mutually exclusive and the first and second wavelength ranges combine to substantially span an entire wavelength range of visible light.