Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

TIME SHARED TWO-FREQUENCY ADDRESSING

IP.com Disclosure Number: IPCOM000025544D
Original Publication Date: 1986-Feb-28
Included in the Prior Art Database: 2004-Apr-04
Document File: 6 page(s) / 235K

Publishing Venue

Xerox Disclosure Journal

Abstract

An improved method of addressing a Liquid Crystal (LC) display using the phenomena of two-f requency addressing is described. The system configuration consists of two planes of horizontal (Y axis) and vertical electrodes (X axis) on glass with the liquid crystal in between without the use of thin film transistors to aid in addressing the display.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 38% of the total text.

Page 1 of 6

XEROX DISCLOSURE JOURNAL

TIME SHARED TWO-FREQUENCY ADDRESSING
Joseph F. Stephany
V. Joseph Hull

Proposed Classification
U.S. Cl. 340/324M

Int. Cl. G08b 23/00

FIG IB

Volume 11 Number 1 January/February 1986 11

[This page contains 1 picture or other non-text object]

Page 2 of 6

TIME SHARED TWO-FREQUENCY ADDRESSING (Cont'd)

I I I I n-*i I

I I

I ON

I I

I

Ii-&+- I I I I

i

I I I

w21 WF

w22 0 FF

12

    XEROX DISCLOSURE JOURNAL Volume 11 Number 1 January/February 1986

[This page contains 1 picture or other non-text object]

Page 3 of 6

TIME SHARED TWO-FREQUENCY ADDRESSING (Cont'd)

12

I

-

CONTROL LINES

-

DRIVER CHIPS

I I

INHIBIT

CONTROL LINES

Tb COMPUTER CLK 1

I

(v II

X LOAD

X LCD0

I

FIG. 3

I I 1 I I

LATCHS

EXCUfSlVE

NORS

NAND GATES

1

SHIFT REGISTER

CLK

FJG 4

    XEROX DISCLOSURE JOURNAL Volume 11 Number 1 January/February 1986 13

[This page contains 1 picture or other non-text object]

Page 4 of 6

TIME SHARED TWO-FREQUENCY ADDRESSING (Cont'd)

An improved method of addressing a Liquid Crystal (LC) display using the phenomena of two-f requency addressing is described. The system configuration consists of two planes of horizontal (Y axis) and vertical electrodes (X axis) on glass with the liquid crystal in between without the use of thin film transistors to aid in addressing the display.

Two-frequency addressing 1s basically the use of two different frequencies for the purpose of turning "on" and "off" the LC. This has the advantage of greater multiplexing capability, but usually requires very complex waveforms utilizing unusual voltages or eiectricaliy floating drivers. This is a great inconvenience which adds to the cost of the drive electronics. It IS the purpose of this improved method of addressing a LC display to simplify the drive electronics, so that no floating or unusual voltages need be applied to the LC. A further purpose is to reduce the burden upon either the computer or control device, as well as any interface, by simplifying the drive requirements, so that extensive waveform generating circuitry IS not necessary.

Figures 1A and 1B illustrate the device configuration 10 and the waveforms necessary to drive it and is the preferred embodiment. Waveforms Yl to Y3 show the waveforms applied with the Y=l line in the selected state. Waveforms X1 to X3 are applied to the X axis with X=l and X=3 being rroff'l states and X=2 being an rron" state. The LC display 10 is being scanned a line at a time where the line is horizontal. The operation is shown with two complete lines being displayed, one for positive charging and one for negative charging. It 1s assumed that the X lines are addressed twice with the same information during these two intervals.

The resulting waveforms upon the LC are shown in Figure 2, Here the waveform W 12 represents an rron" state, whereas the remaining waveforms represent rroffrl states. Only four of the nine waveforms are shown. The ones not shown are exactly the same as either W21 or W22 with the exception that some ma...