Backlight unit of liquid crystal display device

• US 20080123024A1
• Filed: 10/03/2007
• Published: 05/29/2008
• Est. Priority Date: 11/24/2006
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Philips LCD Company Limited (LG Display Co., Ltd.)
• Inventors: Han, Sang Ho, Moon, Je Young
• Granted Patent: US 8,212,464 B2
• Time in Patent Office: Days
• US Class Current: 349/71
• 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: H01J 1/63 characterised by the luminescent material

Abstract

This invention relates to a backlight unit of a liquid crystal display device using a cold cathode fluorescent lamp that is capable of realizing pure colors and having a broad color reproduction range. A backlight unit of a liquid crystal display device according to an embodiment of the present invention includes at least one lamp including a first red phosphor having a dominant wavelength of about 620 nm, a second red phosphor having a dominant wavelength of about 658 nm, a green phosphor having a dominant wavelength of about 515 nm and a blue phosphor having a dominant wavelength of about 447 nm; a bottom cover in which the lamp is disposed; and an optical member disposed on the lamp.

Claims

1. A backlight unit of a liquid crystal display device which irradiates light onto a liquid crystal display panel, comprising:

at least one lamp including a first red phosphor having a dominant wavelength of about 620 nm, a second red phosphor having a dominant wavelength of about 658 nm, a green phosphor having a dominant wavelength of about 515 nm and a blue phosphor having a dominant wavelength of about 447 nm;

a bottom cover in which the lamp is disposed; and

an optical member disposed on the lamp.

2. The backlight unit of a liquid crystal display device according to claim 1, wherein the lamp is a cold cathode fluorescent lamp.

3. The backlight unit of a liquid crystal display device according to claim 1, wherein in a phosphor spectrum area, the first red phosphor is about 15-20% of the area thereof, the second red phosphor is about 30-40% of the area thereof, the green phosphor is about 20-30% of the area thereof and the blue phosphor is about 20-25% of the area thereof.

4. The backlight unit of a liquid crystal display device according to claim 1, wherein the first red phosphor is formed of YVO₄ phosphor, the second red phosphor is formed of Ge phosphor, the green phosphor is formed of a mixture of manganese added to a phosphor of a BAM group phosphor, and the blue phosphor is formed of a blue phosphor of a SCA group phosphor.

5. A four-wavelength lamp for a liquid crystal display devise comprising:

a first red phosphor having a dominant wavelength;

a second red phosphor having a dominant wavelength substantially different from that of the first red phosphor;

a green phosphor having a dominant wavelength; and

a blue phosphor having a dominant wavelength such that a broad color reproduction range is realized.

6. A method of manufacturing a four-wavelength lamp for a liquid crystal display devise compromising:

forming a first red phosphor of a yttrium vanadate (YVO₄) phosphor;

forming a second red phosphor of a germanium (Ge) phosphor;

forming a green phosphor; and

forming a blue phosphor.

7. The method of claim 6, wherein the green phosphor includes a mixture of manganese added to a phosphor of a BAM group phosphor.

8. The method of claim 6, wherein the blue phosphor is an SCA group phosphor.