IP Library Granted Patent US 7,817,223
Granted Patent B2
US 7,817,223 · App. 11/924,641 · Granted Oct 19, 2010

Liquid crystal display device

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Quick Facts
Patent No.
US 7,817,223
App. No.
11/924,641
Granted
Oct 19, 2010
Kind
B2
Abstract

The present invention provides a display device of high brightness which can eliminate brightness irregularities on a display surface while preventing the degradation of display quality attributed to an undesired electric field generated at the time of performing inverter driving of the cold cathode fluorescent lamps of a backlight. In a liquid crystal display device, a plurality of cold cathode fluorescent lamps of a backlight unit is arranged along a short axis of the display device. The cold cathode fluorescent lamp has a high-voltage electrode thereof connected to an inverter circuit and a ground electrode thereof connected to a ground. Further, the plurality of cold cathode fluorescent lamps arranged along the short axis have electrodes thereof arranged alternately between the high-voltage electrode and the ground electrode.

Claims (10)

1. A liquid crystal display device comprising:

a liquid crystal panel which interposes liquid crystal between a first panel substrate having thin film transistors and a second panel substrate having color filters; and

a backlight unit which supplies light to the liquid crystal panel, wherein

the backlight unit includes a plurality of cold cathode fluorescent lamps which extends toward a second side portion from a first side portion;

the cold cathode fluorescent lamps include a first cold cathode fluorescent lamp and a second cold cathode fluorescent lamp;

the first cold cathode fluorescent lamp connects an electrode formed on a first side portion thereof to an inverter circuit on a first printed circuit board and connects an electrode formed on a second side portion thereof to a ground;

the second cold cathode fluorescent lamp connects an electrode formed on a second side portion thereof to an inverter circuit on a second printed circuit board and connects an electrode formed on a first side portion thereof to a ground, and

the inverter circuits formed on the first printed circuit board are configured such that the respective neighboring inverter circuits supply AC voltages having phases opposite to each other.

2. A liquid crystal display device according to claim 1 , wherein the first cold cathode fluorescent lamp and the second cold cathode fluorescent lamp are alternately arranged.

3. A liquid crystal display device according to claim 1 , wherein the first cold cathode fluorescent lamp and the second cold cathode fluorescent lamp are alternately arranged for every two other cold cathode fluorescent lamps.

Assignments (4)
COMPANY SPLIT PLAN TRANSFERRING FIFTY (50) PERCENT SHARE OF PATENTS AND PATENT APPLICATIONS Recorded Dec 12, 2011
From: HITACHI DISPLAYS, LTD.
To: IPS ALPHA SUPPORT CO., LTD.
Reel/Frame 027362/0532 →
MERGER/CHANGE OF NAME Recorded Dec 12, 2011
From: IPS ALPHA SUPPORT CO., LTD.
To: PANASONIC LIQUID CRYSTAL DISPLAY CO., LTD.
Reel/Frame 027363/0282 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded May 4, 2011
From: HITACHI DISPLAY DEVICES, LTD.
To: HITACHI DISPLAYS, LTD.
Reel/Frame 026223/0293 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Feb 28, 2008
From: WATANABE, SAKAE; KURIHARA, HIROSHI; NISHIYAMA, SEIICHI
To: HITACHI DISPLAYS, LTD; HITACHI DISPLAY DEVICES, LTD.
Reel/Frame 020575/0888 →