BACKLIGHT ASSEMBLY HAVING EXTERNAL ELECTRODE FLUORESCENT LAMP, METHOD OF DRIVING THEREOF AND LIQUID CRYSTAL DISPLAY HAVING THE SAME
First Claim
1. A method of driving an external electrode fluorescent lamp (EEFL) in a lamp unit, the lamp unit including a plurality of parallel-connected EEFLs, and an external electrode disposed at least one end of each of the EEFLs, the method comprising:
- (a) converting an external dimming signal into an analogue dimming signal;
(b) generating a first switching signal based on an external on-off control signal, the analogue dimming signal and a lamp current level signal;
(c) converting an external DC power signal into a pulse power signal based on the first switching signal;
(d) converting the pulse power signal into an AC power signal;
(e) raising a voltage level of the AC power signal to produce a raised AC power signal;
(f) providing a first end of the lamp unit with a first raised AC power signal of the raised AC power signal;
(g) providing a second end of the lamp unit with a second raised AC power signal of the raised AC power signal, the second raised AC power signal having a phase difference with respect to the first raised AC power signal; and
(h) providing the lamp current level signal based on a current supplied to the lamp unit.
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Accused Products
Abstract
A backlight assembly has a lamp driving device for driving external electrode fluorescent lamps (EEFLs) parallel connected each other. The lamp driving device includes a power switch transistor, a diode, an inverter and a PWM controller. The transistor converts external DC power signal into pulse power signal based on switching signal, the diode prevents rush current from flowing into the transistor. The inverter converts the pulse power signal into AC power signal, raises voltage level of the AC power signal, and provides the lamps with the raised AC power signal. The PWM controller is activated by external on/off signal to provide the transistor with the switching signal so as to regulate voltage level of the AC power signal. The EEFLs can maintain a constant current level, and the backlight assembly can have characteristics of uniform luminance, high luminance and high heat efficiency.
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Citations
20 Claims
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1. A method of driving an external electrode fluorescent lamp (EEFL) in a lamp unit, the lamp unit including a plurality of parallel-connected EEFLs, and an external electrode disposed at least one end of each of the EEFLs, the method comprising:
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(a) converting an external dimming signal into an analogue dimming signal; (b) generating a first switching signal based on an external on-off control signal, the analogue dimming signal and a lamp current level signal; (c) converting an external DC power signal into a pulse power signal based on the first switching signal; (d) converting the pulse power signal into an AC power signal; (e) raising a voltage level of the AC power signal to produce a raised AC power signal; (f) providing a first end of the lamp unit with a first raised AC power signal of the raised AC power signal; (g) providing a second end of the lamp unit with a second raised AC power signal of the raised AC power signal, the second raised AC power signal having a phase difference with respect to the first raised AC power signal; and (h) providing the lamp current level signal based on a current supplied to the lamp unit. - View Dependent Claims (2, 3)
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4. A liquid crystal display (LCD) apparatus comprising:
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a backlight assembly comprising; i) a lamp unit for generating a light, the lamp unit including a plurality of parallel-connected external electrode fluorescent lamps (EEFLs), and an external electrode disposed at least one end of each of the EEFLs; ii) a lamp driving device for receiving an external DC power signal and an external dimming signal, converting the external DC power signal into an AC power signal, detecting a level of a current supplied to the lamp unit, controlling a level of a voltage of the AC power signal supplied to the lamp unit based on the external dimming signal and the detected current level, raising a voltage level of the AC power signal having the controlled voltage level to provide the lamp unit with the raised AC power signal so as to control the lamp unit to generate the light using the raised AC power signal; and iii) an optical sheet for changing an optical distribution of the light generated from the light emitting means; and a display unit, disposed on the optical distribution changing means, for displaying an image by receiving the light from the lamp unit. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A backlight assembly having an external electrode fluorescent lamp (EEFL), the backlight assembly comprising:
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a lamp unit which generates a light, the lamp unit comprising a plurality of parallel-connected EEFLs, and an external electrode disposed at least one end of each of the EEFLs; a lamp driving device which receives an external DC power signal and an external dimming signal, converts the external DC power signal into an AC power signal, detects a level of a current supplied to the lamp unit, controls a level of a voltage of the AC power signal supplied to the lamp unit based on the external dimming signal and the detected current level, raises a voltage level of the AC power signal having the controlled voltage level to provide the lamp unit with the raised AC power signal so as to control the lamp unit to generate the light using the raised AC power signal; and an optical sheet which changes an optical distribution of the light generated from the lamp unit. - View Dependent Claims (17, 18, 19, 20)
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Specification