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1. WO1991000588 - POWER SYSTEM AND SCAN METHOD FOR LIQUID CRYSTAL DISPLAY

Publication Number WO/1991/000588
Publication Date 10.01.1991
International Application No. PCT/US1990/003732
International Filing Date 29.06.1990
Chapter 2 Demand Filed 24.01.1991
IPC
G09G 3/36 2006.01
GPHYSICS
09EDUCATING; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
GARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
3Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
20for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix
34by control of light from an independent source
36using liquid crystals
CPC
G09G 2310/0289
GPHYSICS
09EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
GARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
2310Command of the display device
02Addressing, scanning or driving the display screen or processing steps related thereto
0264Details of driving circuits
0289Details of voltage level shifters arranged for use in a driving circuit
G09G 2320/041
GPHYSICS
09EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
GARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
2320Control of display operating conditions
04Maintaining the quality of display appearance
041Temperature compensation
G09G 2330/02
GPHYSICS
09EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
GARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
2330Aspects of power supply; Aspects of display protection and defect management
02Details of power systems and of start or stop of display operation
G09G 3/36
GPHYSICS
09EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
GARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
3Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
20for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix ; no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
34by control of light from an independent source
36using liquid crystals
G09G 3/3622
GPHYSICS
09EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
GARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
3Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
20for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix ; no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
34by control of light from an independent source
36using liquid crystals
3611Control of matrices with row and column drivers
3622using a passive matrix
G09G 3/3685
GPHYSICS
09EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
GARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
3Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
20for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix ; no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
34by control of light from an independent source
36using liquid crystals
3611Control of matrices with row and column drivers
3685Details of drivers for data electrodes
Applicants
  • POQET COMPUTER CORPORATION [US/US]; 5200 Patrick Henry Drive Santa Clara, CA 95054, US
Inventors
  • FAIRBANKS, John, P.; US
  • YUAN, Andy, C.; US
  • KLINGER, Lance, T.; US
Agents
  • YOUNG, Edel, M. ; Skjerven, Morrill, MacPherson, Franklin & Friel 25 Metro Drive, Suite 700 San Jose, CA 95110, US
Priority Data
374,34030.06.1989US
Publication Language English (EN)
Filing Language English (EN)
Designated States
Title
(EN) POWER SYSTEM AND SCAN METHOD FOR LIQUID CRYSTAL DISPLAY
(FR) SYSTEME D'ALIMENTATION ELECTRIQUE ET PROCEDE DE BALAYAGE POUR AFFICHAGE A CRISTAUX LIQUIDES
Abstract
(EN)
A structure and method for controlling a liquid crystal display takes advantage of the sharp reflectance change over a small voltage change for new liquid crystal display materials, applying ON and OFF pixel voltages very close to the transition voltage of the liquid crystal material and regulating the applied voltage to remain reliably near and on the desired side of this transition voltage. Also, a net zero DC voltage across pixels of the crystal is maintained using a switching mode close to half the frequency of prior art modes. Driving voltages are provided by a switching regulator rather than the prior art voltage divider, resulting in a significant reduction in operating power. The preferred switching regulator generates only three additional voltages for driving rows and columns of the display, in contrast to the five generated voltages of the prior art voltage divider. An on/off voltage regulator alternately provides or does not provide power to a primary coil (P81), thereby controlling voltage across capacitors (C81, C82, C83, C84) associated with secondary coils (S81, S82, S83, S84). This gives accurate voltage control over a wide range of display loads. This voltage regulator is controlled preferably by the low voltage applied across pixels during the time when the pixels are not in the selected row, that is, during the time when the logic state of a pixel is not provided to the pixel.
(FR)
Structure et procédé de commande d'un affichage à cristaux liquides tirant avantage du changement de réflectance important par rapport à un petit changement de tension pour de nouveaux matériaux d'affichage à cristaux liquides, en appliquant des tensions de pixels ON et OFF très proches de la tension de transition du matériaux à cristaux liquides et en régulant la tension appliquée pour qu'elle reste fiablement proche et du côté désiré de cette tension de transition. De même, une tension à courant continu de zéro net sur les pixels du cristal est maintenue en utilisant un mode de commutation proche de la moitié de la fréquence des modes de l'art antérieur. Des tensions d'attaque sont fournies à l'aide d'un régulateur de commutation plutôt qu'à l'aide d'un diviseur de tension comme dans l'art antérieur, ce qui se traduit par une réduction importante de la puissance d'alimentation électrique de fonctionnement. Le régulateur de commutation préféré génère uniquement trois tensions additionnelles pour l'alimentation des rangées et des colonnes de l'affichage, en comparaison aux cinq tensions générées du diviseur de tension de l'art antérieur. Un régulateur de tension on/off fournit ou ne fournit pas de manière alternative un courant électrique à une bobine principale (P81) commandant ainsi la tension sur les condensateurs (C81, C82, C83, C84) associés aux bobines secondaires (S81, S82, S83, S84). Ceci permet d'obtenir une commande de tension précise sur une plage étendue de charges d'affichage. Ce régulateur de tension est commandé de préférence par la basse tension appliquée sur les pixels pendant le temps durant lequel les pixels ne sont pas dans la rangée sélectionnée, c'est-à-dire pendant le temps où l'état logique d'un pixel n'est pas donné au pixel.
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