US4865425A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Power source device for driving liquid crystal
Assignee: Stanley Electric Co Ltd
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Filing: 1986-12-01
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Granted: 1989-09-12
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Expires: 2006-12-01
Abstract
Abstract A power source device for driving a liquid crystal device comprises an inverter for powering a back-light discharge lamp and a negative voltage power source generator for driving the liquid crystal device. The negative voltage generator is provided as part of the inverter. A step-up transformer of the inverter is commonly used as part of the negative voltage power source generator.
Inventors
- 👤 Uruo Kobayashi
- 👤 Youji Oki
- 👤 Katsunori Kawano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 15:23
CPC Classifications
H; H05; H05B; H05B41/00; H05B41/14; H05B41/26; H05B41/28; H05B41/282; H05B41/2821
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
191 words
A power source device for driving both a liquid crystal device with a DC negative voltage, and an AC driven light source arranged for illuminating said liquid crystal device, the power source device comprising: an inverter circuit coupled to said light source for providing AC power to said light source for lighting said light source, said inverter circuit comprising: a step-up transformer having at least a primary winding, a secondary winding, and a feedback winding; and an oscillator circuit coupled to said primary winding of said step-up transformer for supplying an AC voltage to said primary winding; said secondary winding being coupled to said light source for providing an AC voltage to light said light source; and a negative voltage power source generator comprising: a rectifier circuit coupled to said secondary winding of said step-up transformer for receiving an AC voltage therefrom, and for generating a negative DC voltage from said received AC voltage; and means for coupling said negative DC voltage to said liquid crystal device to drive said liquid crystal device; said rectifier circuit of said negative voltage power source generator comprising diode means for rectifying said AC voltage.
Claim 2
Dependent Claim
191 words
A power source device for driving both a liquid crystal device with a DC negative voltage, and an AC driven light source arranged for illuminating said liquid crystal device, the power source device comprising: an inverter circuit coupled to said light source for providing AC power to said light source for lighting said light source, said inverter circuit comprising: a step-up transformer having at least a primary winding, a secondary winding, and a feedback winding; and an oscillator circuit coupled to said primary winding of said step-up transformer for supplying an AC voltage to said primary winding; said secondary winding being coupled to said light source for providing an AC voltage to light said light source; and a negative voltage power source generator comprising: a rectifier circuit coupled to said secondary winding of said step-up transformer for receiving an AC voltage therefrom, and for generating a negative DC voltage from said received AC voltage; and means for coupling said negative DC voltage to said liquid crystal device to drive said liquid crystal device; said rectifier circuit of said negative voltage power source generator comprising diode means for rectifying said AC voltage.
Claim 3
Dependent Claim
15 words
The power source device of claim 1, wherein said light source is a discharge-type lamp.
Claim 4
Dependent Claim
21 words
The power source device of claim 2, wherein said discharge-type lamp is arranged for back illumination of said liquid crystal device.
Claim 5
Dependent Claim
21 words
The power source device of claim 1, wherein said light source is arranged for back illumination of said liquid crystal device.
Claim 6
Dependent Claim
26 words
The power source device of claim 1, wherein said rectifier circuit is coupled to at least a portion of said secondary winding of said step-up transformer.
Claim 7
Dependent Claim
24 words
The power source device of claim 5, wherein said secondary winding includes a tapped portion, said rectifier circuit being coupled to said tapped portion.
Claim 8
Dependent Claim
15 words
The power source device of claim 6, wherein said light source is a discharge-type lamp.
Claim 9
Dependent Claim
21 words
The power source device of claim 7, wherein said discharge-type lamp is arranged for back illumination of said liquid crystal device.
Claim 10
Dependent Claim
21 words
The power source device of claim 6, wherein said light source is arranged for back illumintion of said liquid crystal device.
Claim 11
Dependent Claim
194 words
A power source device for driving both a liquid crystal device with a DC negative voltage, and an AC driven light source arranged for illuminating said liquid crystal device, the power source device comprising: an inverter circuit coupled to said light source for providing AC power to said light source for lighting said light source, said inverter circuit comprising: a step-up transformer having at least a primary winding, a secondary winding, a feedback winding and a tertiary winding; and an oscillator circuit coupled to said primary winding of said step-up transformer for supplying an AC voltage to said primary winding; said secondary winding being coupled to said light source for providing an AC voltage to light said light source; and a negative voltage power source generator comprising: a rectifier circuit coupled to said tertiary winding of said step-up transformer for receiving an AC voltage therefrom, and for generating a negative DC voltage from said received AC voltage; and means for coupling said negative DC voltage to said liquid crystal device to drive said liquid crystal device; said rectifier circuit of said negative voltage power source generator comprising diode means for rectifying said AC voltage.
Claim 12
Dependent Claim
194 words
A power source device for driving both a liquid crystal device with a DC negative voltage, and an AC driven light source arranged for illuminating said liquid crystal device, the power source device comprising: an inverter circuit coupled to said light source for providing AC power to said light source for lighting said light source, said inverter circuit comprising: a step-up transformer having at least a primary winding, a secondary winding, a feedback winding and a tertiary winding; and an oscillator circuit coupled to said primary winding of said step-up transformer for supplying an AC voltage to said primary winding; said secondary winding being coupled to said light source for providing an AC voltage to light said light source; and a negative voltage power source generator comprising: a rectifier circuit coupled to said tertiary winding of said step-up transformer for receiving an AC voltage therefrom, and for generating a negative DC voltage from said received AC voltage; and means for coupling said negative DC voltage to said liquid crystal device to drive said liquid crystal device; said rectifier circuit of said negative voltage power source generator comprising diode means for rectifying said AC voltage.
Claim 13
Dependent Claim
15 words
The power source device of claim 10, wherein said light source is a discharge-type lamp.
Claim 14
Dependent Claim
21 words
The power source device of claim 11 wherein said discharge-type lamp is arranged for back illumination of said liquid crystal device.
Claim 15
Dependent Claim
21 words
The power source device of claim 10, wherein said light source is arranged for back illumination of said liquid crystal device.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1992-09-11 | 1993-03-13 | 1993-09-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-09-11 | 1997-03-13 | 1997-09-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-09-11 | 2001-03-13 | 2001-09-12 | $7700.00 | Window Closed / Lapsed |