IP Library Granted Patent US 8,610,698
Granted Patent B2
US 8,610,698 · App. 12/700,755 · Granted Dec 17, 2013

Display device

Inventors: Taku Saito (Mobara, JP); Shuuichirou Matsumoto (Mobara, JP); Mitsuru Goto (Chiba, JP)
Assignees: Japan Display Inc.; Panasonic Liquid Crystal Display Co., Ltd.
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Quick Facts
Patent No.
US 8,610,698
App. No.
12/700,755
Granted
Dec 17, 2013
Kind
B2
Abstract

To provide a display device including a switching regulator type power generating circuit which realizes an increase in display quality by an output voltage being more stable, and by suppressing a flickering of a screen. A display device includes a switching regulator type direct current power generating circuit, wherein a period for which a switching element is turned on is determined in such a way as to increase or decrease by a given width when a code of an output voltage with respect to a setting voltage is constant, and the period is determined in such a way as to increase or decrease differently from the given width when the code changes.

Claims (14)

1. A display device comprising:

a display panel; and

a power generating circuit which supplies an output voltage to the display panel,

the power generating circuit including:

a voltage raising circuit which generates the output voltage;

a switching element which drives the voltage raising circuit;

an on signal generating circuit which outputs a signal turning on the switching element to the switching element during an on period;

an output voltage detection circuit which detects a polarity of the output voltage of the voltage raising circuit with respect to setting voltage, and outputs a code; and

an on period determination unit which determines a length of the on period of a following cycle based on the code,

wherein the on period determination unit determines the on period of the following cycle in such a way that the length of the on period increases or decreases by a predetermined width in accordance with a timing at which the code is the same in two consecutive cycles,

and determines the on period of the following cycle in such a way that the length of the on period increases or decreases differently from the predetermined width in accordance with a timing at which the code differs in two consecutive cycles.

2. A display device according to claim 1 , wherein the on period determination unit including a storage module which stores on period information,

the storage module stores one item of the on period information in accordance with a timing at which the code differs in two consecutive cycle periods.

3. A display device according to claim 1 , wherein the on period determination unit, in accordance with a timing at which the code differs in two consecutive cycle periods, determines the length of the on period by taking an average value of the on period corresponding to the timing and the on period stored in the storage module.

Assignments (7)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jul 10, 2025
From: JAPAN DISPLAY INC
To: MAGNOLIA PURPLE CORPORATION
Reel/Frame 071890/0202 →
NUNC PRO TUNC ASSIGNMENT Recorded Nov 17, 2023
From: PANASONIC LIQUID CRYSTAL DISPLAY CO., LTD.
To: PANASONIC INTELLECTUAL PROPERTY CORPORATION OF AMERICA
Reel/Frame 065615/0327 →
CHANGE OF NAME Recorded Oct 28, 2013
From: JAPAN DISPLAY EAST INC.
To: JAPAN DISPLAY INC.
Reel/Frame 031506/0242 →
CHANGE OF NAME Recorded Oct 25, 2013
From: HITACHI DISPLAYS, LTD.
To: JAPAN DISPLAY EAST, INC.
Reel/Frame 031496/0663 →
COMPANY SPLIT PLAN TRANSFERRING FIFTY (50) PERCENT SHARE IN PATENT APPLICATIONS Recorded Oct 20, 2011
From: HITACHI DISPLAYS, LTD.
To: IPS ALPHA SUPPORT CO., LTD.
Reel/Frame 027092/0684 →
MERGER Recorded Oct 20, 2011
From: IPS ALPHA SUPPORT CO., LTD.
To: PANASONIC LIQUID CRYSTAL DISPLAY CO., LTD.
Reel/Frame 027093/0937 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Feb 5, 2010
From: SAITO, TAKU; MATSUMOTO, SHUUICHIROU; GOTO, MITSURU
To: HITACHI DISPLAYS, LTD.
Reel/Frame 023902/0299 →
Priority Claims (1)
JP 2009-061415 · Mar 13, 2009 · national
Continuity (1)
Related Publication 20100231570A1 · Sep 16, 2010