US 5,739,803 A · Electronic system for driving liquid crystal displays

Abstract

A novel electronic apparatus for driving passive x-y addressed liquid crystal displays (LCDs) and having improved display performance is disclosed and claimed. This apparatus is comprised of row driving integrated circuits capable of driving row lines of the LCD with a pattern of voltages corresponding to the basis vectors of a linear transform matrix. Column driver circuits containing analog CMOS pixel memory store video information and compute the linear transform of the pixel matrix. High voltage amplifier circuits to drive the column lines with voltages corresponding to the linear transform of the pixel matrix columns can be monolithically integrated with the transform computation circuitry. The LCD screen inherently performs the inverse transform and displays the desired pixel matrix. The speed and contrast of the LCD are improved, allowing the display of video rate images on passive LCD screens.

Claims19

Dependent claims

An apparatus for addressing a liquid crystal display with video pixel information, comprising:

(a) analog memory for storing a first and a second value, wherein the first value is representative of the video pixel information and the second value is representative of a square root of a constant minus a square of the video pixel information;
(b) analog computation means for computing a linear transform of the first and second values;
and
(c) at least one amplifier for driving at least one column electrode of the liquid crystal display with a first voltage representative of the linear transform of the first value minus the linear transform of the second value and a second voltage representative of the linear transform of the first value plus the linear transform of the second value.

1 more element

A method for addressing a liquid crystal display having multiple overlapping row and column electrodes affixed to substrates on opposite sides of liquid crystal material wherein the overlapping row and column electrodes define a matrix of pixels that display gray-scale video information, the method comprising the steps of:

(a) storing the gray-scale video information as a matrix of analog electric charges in an analog vector-matrix multiplier;
(b) multiplying the matrix of stored video information by a basis vector in the analog vector-matrix multiplier, wherein the basis vector is selected from a group consisting of a binary and a ternary basis vector, whereby a video information transform vector is generated;
(c) addressing the column electrodes with a first set of voltages that is representative of the video information transform vector;
and
(d) simultaneously addressing the row electrodes with a second set of voltages that is representative of the basis vector, wherein at least two row electrodes are addressed with non-zero voltages.

2 more elements

An apparatus for addressing a liquid crystal display, wherein the liquid crystal display has multiple overlapping row and column electrodes affixed to substrates on opposite sides of liquid crystal material and wherein the overlapping row and column electrodes define a matrix of pixels that display gray-scale video information, comprising:

an analog vector-matrix multiplier, wherein the gray-scale video information is stored as a matrix of analog electric charges within the analog vector-matrix multiplier, and wherein the analog vector-matrix multiplier computes a video information transform vector by multiplying the matrix of analog electric charge with a basis vector, wherein the basis vector is selected from the group consisting of a binary and a ternary basis vector;
and
wherein the video information transform vector is applied to the column electrodes and the basis vector simultaneously is applied the row electrodes and wherein at least two elements of the basis vector are non-zero.

Dependencies are inferred from the claim text.

Electronic system for driving liquid crystal displays

Life of this patent

Electronic system for driving liquid crystal displays

Life of this patent

Abstract

Claims19