US 2009/0021470 A1Published application

Backlight assembly and display apparatus having the same

OwnerKwang-Hee Lee, Jin-Woo Parkinventors

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Abstract

A light-emitting part includes (N)-th row light-emitting diodes (LEDs) and (N+1)-th row LEDs, wherein ‘N’ is a natural number. A pulse width modulation (PWM) control part generates (N)-th and (N+1)-th PWM signals. A driving voltage generating part includes an (N)-th driving element that applies an (N)-th driving voltage to the (N)-th row LEDs, and an (N+1)-th driving element that applies an (N+1)-th driving voltage to the (N+1)-th row LEDs, wherein a phase of the (N+1)-th driving voltage is delayed by about 360 degrees/M with respect to the phase of the first driving voltage, wherein ‘M’ is a natural number that is more than 2. A current balance part controls an amplitude of an (N)-th driving current applied to the (N)-th row LEDs and an amplitude of (N+1)-th driving current applied to the (N+1)-th row LEDs. Therefore, a striped image may be prevented from being displayed on the display apparatus.

Claims20

Dependent claims

A backlight assembly comprising:

a light-emitting part including a plurality of (N)-th row light-emitting diodes (LEDs) that are connected to each other in series, and a plurality of (N+1)-th row LEDs that are connected to each other in series, wherein ‘N’ is a natural number;
a pulse width modulation (PWM) control part generating an (N)-th PWM signal for controlling the (N)-th row LEDs, and an (N+1)-th PWM signal for controlling the (N+1)-th row LEDs;
a driving voltage generating part including an (N)-th driving element that applies an (N)-th driving voltage to the (N)-th row LEDs in response to the (N)-th PWM signal, and an (N+1)-th driving element that applies an (N+1)-th driving voltage to the (N+1)-th row LEDs in response to the (N+1)-th PWM signal, wherein a phase of the (N+1)-th driving voltage is delayed by about 360 degrees/M with respect to a phase of the first driving voltage, wherein ‘M’ is a natural number that is more than 2;
and
a current balance part being electrically connected to the driving voltage generating part and the light-emitting part to control an amplitude of an (N)-th driving current that is applied to the (N)-th row LEDs and an amplitude of an (N+1)-th driving current that is applied to the (N+1)-th row LEDs.

2 more elements

A display apparatus comprising:

a backlight assembly emitting light;
and
a display panel displaying an image using the light generated from the backlight assembly, wherein the backlight assembly comprises:
a light-emitting part including a plurality of (N)-th row light-emitting diodes (LEDs) that that connected to each other in series, and a plurality of (N+1)-th row LEDs that that connected to each other in series, wherein ‘N’ is a natural number;
a pulse width modulation (PWM) control part generating an (N)-th PWM signal for controlling the (N)-th row LEDs, and an (N+1)-th PWM signal for controlling the (N+1)-th row LEDs;
a driving voltage generating part including an (N)-th driving element that applies an (N)-th driving voltage to the (N)-th row LEDs in response to the (N)-th PWM signal, and an (N+1)-th driving element that applies an (N+1)-th driving voltage to the (N+1)-th row LEDs in response to the (N+1)-th PWM signal, wherein a phase of the (N+1)-th driving voltage is delayed by about 360 degrees/M with respect to a phase of the first driving voltage, wherein ‘M’ is a natural number that is more than 2;
and
a current balance part being electrically connected to the driving voltage generating part and the light-emitting part to control an amplitude of an (N)-th driving current that is applied to the (N)-th row LEDs and an amplitude of an (N+1)-th driving current that is applied to the (N+1)-th row LEDs.

5 more elements

Dependencies are inferred from the claim text.