EP0199361A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Driver circuit for liquid crystal display
Assignee: Panasonic Holdings Corp
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Filing: 1986-04-25
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Granted: —
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Expires: 2006-04-25
Abstract
Abstract A driver circuit for a liquid crystal display for driving a liquid crystal panel (1) in a A.C. manner. In this circuit, a display signal voltage to be applied to one electrode of the liquid crystal cell and a common voltage to be applied to a common electrode (6) thereof are inverted in their polarity with a certain period, respectively (14, 15; Q 6 - 0 9 ), and at least one of the signal voltage and common voltage that are being polarity-inverted with the certain period is varied in its D.C. level by the same amount in the same direction in each period so that they can be adjusted so as to be in a predetermined relation for A.C. driving (O 1 - Q 2 , V R1 , R 4 , R 6 ; Q 3 , V R2 , R 6 ).
Inventors
- 👤 Masaki Hosono
- 👤 Yukio Nemoto
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 10:25
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/137; G02F1/139; G09; G09G; G09G3/00; G09G3/20; G09G3/34; G09G3/36; G09G3/3611; G09G3/3648; G09G3/3655; G02F1/133; G09G3/3614; G09G2320/00; G09G2320/02; G09G2320/0204
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
111 words
A driver circuit for A.C. driving a liquid crystal display cell comprising polarity inversion means (14, 15) for polarity-inverting, with a given period, a display signal voltage to be applied to one electrode of the liquid crystal display cell and a common voltage to be applied to an opposite common electrode thereof, respectively; said driver circuit being characterized by D .C. level shifting means (Q 1 , Q 2 , R 4 , R 5 , VR I ) for varying D.C. voltage level of at least one of the signal voltage and common voltage polarity-inverted with the given period by a same amount in a same direction in each period.
Claim 2
Dependent Claim
111 words
A driver circuit for A.C. driving a liquid crystal display cell comprising polarity inversion means (14, 15) for polarity-inverting, with a given period, a display signal voltage to be applied to one electrode of the liquid crystal display cell and a common voltage to be applied to an opposite common electrode thereof, respectively; said driver circuit being characterized by D .C. level shifting means (Q 1 , Q 2 , R 4 , R 5 , VR I ) for varying D.C. voltage level of at least one of the signal voltage and common voltage polarity-inverted with the given period by a same amount in a same direction in each period.
Claim 3
Dependent Claim
47 words
A driver circuit according to Claim 1, comprising a switching element (3) having a first electrode to be supplied with a switching signal, second electrode to be supplied with a display signal voltage and third electrode connected with one electrode of the liquid crystal cell. or 2
Claim 4
Dependent Claim
90 words
A driver circuit according to Claim 1/, wherein said D.C. level shifting means comprises a first transistor (Q 1 ) for receiving the polarity inverted signal voltage, a series circuit comprising first and second resistors (R 4 , R 5 ) connected with the emitter of said first transistor, a signal voltage output terminal (16) provided at a connection point of said first and second resistors and a constant current source (Q 2 , VR 1 ) with its current value being adjustable, connected in parallel to said second resistor.
Claim 5
Dependent Claim
30 words
A driver circuit according to Claim 3, wherein said constant current source includes a series circuit comprising a second transistor (Q 2 ) and a variable resistor (VR 1 ).
Claim 6
Dependent Claim
47 words
A driver circuit according to Claim 1 or 2, wherein said common voltage polarity inversion means comprises a constant voltage device (Q 3 ) and switching means (Q 6 - Q 9 ) for alternately outputting two voltages provided from both ends of said constant voltage device.
Claim 7
Dependent Claim
28 words
A driver circuit according to Claim 5, wherein said D.C. level shifting means comprises means (VR 2 ) for varying the voltage applied to said constant voltage device.
References Cited (Backward Citations)
No citation records indexed.
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