IP Library Granted Patent US 9,232,599
Granted Patent B2
US 9,232,599 · App. 14/509,237 · Granted Jan 5, 2016

Liquid crystal display device

Inventor: Jae-Ho Lee (Gyeonggi-do, KR)
Assignee: LG Display Co., Ltd.
H05B33/0854F21K9/56G02F1/133603G02F1/133609G02F1/133621G02F2001/133612
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Quick Facts
Patent No.
US 9,232,599
App. No.
14/509,237
Granted
Jan 5, 2016
Kind
B2
Abstract

A liquid crystal display device includes a backlight unit including an LED assembly, wherein the LED assembly includes: a plurality of LED packages; an LED PCB on which the plurality of LED packages are arranged being spaced apart from each other; and an LED driving circuit board that is connected to the LED PCB and includes a LED driving circuit, wherein the LED package includes first and second LED chips emitting two colors, respectively, out of red, green and blue, and a fluorescent substance emitting the other one color out of the red, green and blue, wherein a temperature sensor is formed in the LED PCB, and wherein the first or second LED chip is supplied with a compensated voltage according to temperature change by the temperature sensor.

Claims (23)

1. A liquid crystal display device, comprising:

a backlight unit including an LED assembly,

wherein the LED assembly includes:

a plurality of LED packages;

an LED PCB on which the plurality of LED packages are arranged being spaced apart from each other; and

an LED driving circuit board that is connected to the LED PCB and includes a LED driving circuit,

wherein the LED package includes first and second LED chips emitting two colors, respectively, out of red, green and blue, and a fluorescent substance emitting the other one color out of the red, green and blue,

wherein a temperature sensor is formed in the LED PCB,

wherein the first or second LED chip is supplied with a compensated voltage according to temperature change by the temperature sensor,

wherein the first LED chips emits the blue, the second LED chip emits the red, and the fluorescent substance emits the green,

wherein the LED driving circuit includes a PWM control IC, a DC-DC block, and an LED sensing portion,

wherein the LED sensing portion includes first and second LED sensing portions that each include a plurality of resistors, and are connected to the first and second LED chips, respectively,

wherein the temperature sensor is connected to the second LED sensing portion,

wherein the DC-DC block supplies DC powers to the first and second LED chips independently,

wherein the PWM control IC controls an output current of the DC-DC block, and

wherein the LED sensing portion feeds output voltages of the first and second LED chips back to the PWM control IC,

wherein the output voltage of the second LED chip is fed back to the PWM control IC through the temperature sensor, and

wherein the output voltage of the first LED chip is fed back to the PWM control IC without the temperature sensor.

2. The device of claim 1 , wherein a full width at half maximum (FWHM) of light emission of the fluorescent substance is about 70 nm or less.

3. The device of claim 1 , wherein the second LED sensing portion includes the plurality of resistors and the temperature sensor, and

wherein a resistance value of the temperature sensor varies proportional to a temperature.

4. The device of claim 1 , wherein a resistance value of the temperature sensor is varied proportional to temperature change of the first or second LED chip.

5. The device of claim 4 , wherein a driving voltage supplied to the first or second LED chip rises as a measured temperature value of the temperature sensor is higher.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Oct 8, 2014
From: LEE, JAE-HO
To: LG DISPLAY CO., LTD.
Reel/Frame 033913/0422 →
Priority Claims (1)
KR 10-2013-0120915 · Oct 10, 2013 · national
Continuity (1)
Related Publication 20150102748A1 · Apr 16, 2015