Matrix drive liquid crystal display device with high horizontal resolution and low duty ratio

• US 4,805,994 A
• Filed: 04/14/1988
• Issued: 02/21/1989
• Est. Priority Date: 03/18/1986
• Status: Expired due to Term

• Current Assignee: Citizen Watch Co Limited (Citizen Electronics Company Limited)
• Original Assignee: Citizen Watch Co Limited (Citizen Electronics Company Limited)
• Inventors: Miyajima, Akira
• Primary Examiner(s): Miller, Stanley D.
• Assistant Examiner(s): Duong, Tai V.
• Application Number:
  US07/183,492
• Time in Patent Office: 313 Days
• Field of Search: 350/332, 350/333, 350/334, 350/335, 350/336, 340/759, 340/784, 340/802, 340/805, 340/765, 340/752, 358/241
• US Class Current: 349/145
• CPC Class Codes: G02F 1/134336 Matrix
• CPC Class Codes: G02F 2203/30 Gray scale
• CPC Class Codes: G09G 2310/027 Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters
• CPC Class Codes: G09G 2310/0297 Special arrangements with multiplexing or demultiplexing of display data in the drivers for data electrodes, in a pre-processing circuitry delivering display data to said drivers or in the matrix panel, e.g. multiplexing plural data signals to one D/A converter or demultiplexing the D/A converter output to multiple columns
• CPC Class Codes: G09G 3/2014 by modulation of the duration of a single pulse during which the logic level remains constant
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers
• CPC Class Codes: G09G 3/3685 Details of drivers for data electrodes

Abstract

A liquid crystal display device in which each of the scanning electrodes has a center portion, an upper projection extending upwards from the center portion and a lower projection extending downwards from the center portion, and two picture elements are formed vertically each in an area comprising the upper projection and the center portion and an area comprising the lower projection and the center portion, and the phases in which the data to be given to the signal electrodes are sampled from even scanning picture signals are made different from the phases in which the data to be given to the signal electrodes are sampled from odd scanning picture signals, so that when the scanning electrodes are selected, the data for four scans of picture signals are given to the signal electrodes.

Claims

1. A quadruplex matrix type liquid crystal display device in which sampling holds are taken with a frequency of n times with respect to each of 4m picture signals necessary for a one-field picture display where n and m are integers;

whenever 4n sampling holds are taken with repect to 4 picture signals, selective pulses are successively sent by time division from m horizontal scanning electrodes;

every 4n sampling data for 4 picture signals with respect to the selective pulse from one of the horizontal scanning electrodes are given by 4n signal electrodes, respectively; and

thus pictures are formed, wherein

(a) an order of the data sampled by the (k)th (where k=1, 2 . . . n) sampling of each of 4 continuous picture signals is (4p-4)n+k, (4p-3)n+k, (4p-2)n+k and (4p-1)n+k (where k=1, 2 . . . n, and p=1, 2 . . . m), ((4p-4)n+k)th and ((4p-2)n+k)th samplings are in phase and ((4p-3)n+k)th and ((4p-1)n+k)th samplings are in phase and are 180°

out of phase with the ((4p-4)n+k)th and ((4p-2)n+k)th samplings;

(b) each of portions for forming directly picture elements of said m horizontal scanning electrodes includes a center portion in the shape of a rectangle having a width of W and a length of L;

said length of L is divided by 2n to make 2n divisions of said center portion, each of said portions for forming directly picture elements further includes n upper projections each having a length of L/2n and a width of W/3 and extending upwards from the respective center portion divisions in odd numbers counted in a direction of said L from one end of said each horizontal scanning electrode; and

n lower projections each having a length of L/2n and a width of W/3 and extending downwards from the respective center portion divisions in even numbers;

(c) each of portions for forming directly picture elements of said 4n signal electrodes is shaped so that along a width of 4Wm/3, electrodes for producing m picture elements each having a length of L/2n and a width of 2W/3 are coupled by means of leads; and

(d) a region made by adding the width (W/3) of the upper projection of each of said scanning electrodes to the width (W) of the center portion which exists on a lower part of said upper projection is vertically divided into two equal parts, the upper part and the lower part of the two equally divided parts of each scanning electrode are called a first position and a third position respectively of the scanning electrode, and also a region made by adding the width (W/3) of the lower projection of each of the scanning electrodes to the width (W) of the center portion which exists]on an upper part of the lower projection is vertically divided into two equal parts, the upper part and the lower part of the two equally divided parts are called a second position and a fourth position respectively of the saanning electrode, and furthermore, the positions of each of the signal electrodes opposite to the corresponding positions of each of said scanning electrodes are also called said first position, said third position, said second position and said foutth position of the signal electrode, said ((4p-4)n+k)th sampling data are given into said first position of the signal electrode, said ((4p-3)n+k)th sampling data are given into said second position of the signal electrode, said ((4p-2)n+k)th sampling data are given into said third position of the signal electrode and said ((4p-1)n+k)th sampling data are given into said fourth position of the signal electrode.