Display device

• US 4,791,417 A
• Filed: 10/31/1984
• Issued: 12/13/1988
• Est. Priority Date: 03/01/1983
• Status: Expired due to Fees

• Current Assignee: Tadeusz Bobak
• Original Assignee: Tadeusz Bobak
• Inventors: Bobak, Tadeusz
• Primary Examiner(s): Brigance, Gerald L.
• Assistant Examiner(s): Brier, Jeffery A.
• Application Number:
  US06/713,409
• Time in Patent Office: 1,504 Days
• Field of Search: 340/700, 340/701, 340/702, 340/703, 340/752, 340/784, 340/792, 340/793, 340/815.27, 340/785, 340/767, 340/765, 340/787, 340/805, 350/334
• US Class Current: 345/89
• CPC Class Codes: G02F 1/13336 Combining plural substrates to produce large-area displays, e.g. tiled displays
• CPC Class Codes: G02F 1/134345 Subdivided pixels, e.g. for grey scale or redundancy
• CPC Class Codes: G02F 2203/30 Gray scale
• CPC Class Codes: G09F 9/35 being liquid crystals G09F9/302 takes precedence; liquid crystal materials C09K19/00; liquid crystal panels comprising a number of electrodes in a single cell per se G02F1/13
• CPC Class Codes: G09G 2300/026 Video wall, i.e. juxtaposition of a plurality of screens to create a display screen of bigger dimensions
• CPC Class Codes: G09G 3/2074 using sub-pixels
• CPC Class Codes: G09G 3/36 using liquid crystals
• CPC Class Codes: H04N 3/127 using liquid crystals

Abstract

The device comprises a two-dimensional display panel (20) composed of interchangable unit modular (24). Each module is composed of display elements which are nematic or smectic LCD cells. Half-tones may be produced by either changing the contrast of the LCD or in subdividing each display element into several unit cells which are, as desired, switched to light or dark and thus producing the impression of a more or less dark dot. The device serves to communicate information in the form of fixed or changing images or sign groups and can also be used for advertisement.

Claims

1. A large panel display device, comprising:

a viewable panel having a front surface for displaying an image thereon and a rear side opposing to said front surface;

said front surface being comprised of a plurality of display elements, each display element including a plurality of liquid crystal display cells, each liquid crystal display cell having a viewable reflective surface which is different in size than the remaining reflective surfaces of the other display cells in said display element and which is operable in a first mode wherein light directed at said reflective surface is reflected by said surface and in a second mode wherein light directed at said reflective surface is absorbed at said reflective surface;

said image being produced solely by the reflection of light from said front surface and said large panel display device lacking and requiring no rear lighting for illuminating said front surface whereby said large panel display device is capable of being positioned against an opaque support;

control means for independently controlling said first and second mode of operation of each liquid crystal display cell, said control means providing energizing signals to said cells having a variable phase shift adjustable between 0° and

180°

; and

support means for supporting said display elements to form said large panel display device.

2. A large panel display device as set forth in claim 1, wherein the control means can selectively change the visual characteristic of one or more display cells within any display element.

3. A large panel display device as set forth in claim 2, wherein the display cells are rectangular in shape.

4. A large panel display device as set forth in claim 1, wherein each of the display elements has three display cells, the display cells having a relative ratio of the size of display surfaces of 2:

3;

4.

5. A large panel display device as set forth in claim 4, wherein the display cells are nematic phase liquid crystals.

6. A large panel display device as set forth in claim 4, wherein the display cells are smectic phase liquid crystals.

7. A large panel display device as set forth in claim 2, wherein the display elements are identical to each other.

8. A large panel display device as set forth in claim 7, wherein said large panel display device is comprised of a plurality of display modules and said display modules are positioned relative to one another to produce the front surface and wherein each of said display modules is, in turn, comprised of a plurality of said display elements.

9. A large panel display device as set forth in claim 8, wherein the display modules are identical to each other.

10. A large panel display device as set forth in claim 9, wherein the display elements within a display module are arranged in a matrix.

11. A large panel display device as set forth in claim 10, wherein the display modules are arranged in a matrix.

12. A large panel display device as set forth in claim 11, wherein the display modules are physically independent from each other.

13. A large panel display device as set forth in claim 2, wherein the display cells change from a first visual characteristic to a second visual characteristic.

14. A large panel display device as set forth in claim 13, wherein the first visual characteristic is black and the second visual characteristic is white.