LIQUID CRYSTAL IMAGE DISPLAY PANEL WITH INTEGRATED ADDRESSING CIRCUITRY

• US 3,840,695 A
• Filed: 10/10/1972
• Issued: 10/08/1974
• Est. Priority Date: 10/10/1972
• Status: Expired due to Term

• Current Assignee: Magnascreen Corporation
• Original Assignee: Albert G. Fischer
• Inventors: Fischer, Albert G.
• Primary Examiner(s): Richardson, Robert L.
• Assistant Examiner(s): Saffian, Mitchell
• Application Number:
  US05/296,425
• Time in Patent Office: 728 Days
• Field of Search: 178/5.4BD,7.3D,5.4R,7.5D,5.4EL 340/166R,324M,166EL 315/169TV 350/150
• US Class Current: 348/761
• CPC Class Codes: G02F 1/133526 Lenses, e.g. microlenses or Fresnel lenses
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: G09G 3/3607 for displaying colours or for displaying grey scales with a specific pixel layout, e.g. using sub-pixels display of colours in flat matrix panels other than liquid crystal displays G09G3/2003; grey scales specific for television H04N3/127
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence
• CPC Class Codes: G09G 3/3688 suitable for active matrices only

Abstract

A flat, non-vacuum display panel using a lightmodulating layer of a voltage-dependent, optically active material of twisted nematic liquid crystals, X-Y matrix addressed by an array of coextensive, vacuum-deposited, interconnected thin film transistors which are scanned from the periphery of the flat panel by electronic shift registers. The panel is illuminated from the rear by white light, which passes a mosaic color filter for color television display. The invention hereindescribed was made in the course of or under a contract with the U.S. Air Force.

Claims

1. A color television display system comprising:

a liquid crystal layer exhibiting the property of rotating the polarization plane of transmitted light in response to application of an electric field across said liquid crystal layer, a front electrode member for said liquid crystal layer comprised of a layer of electrical conductive material transmissive to light positioned on one side of said liquid crystal layer, a back electrode member transmissive to light for said liquid crystal layer comprised of a plurality of electrical conductive contact members on an insulating support member positioned on the other side of said liquid crystal layer with respect to front electrode, a thin film transistor array comprising a plurality of spaced apart interconnected transistors which are disposed upon the insulating support member side facing the liquid crystal layer, with individual transistors being spaced between the electrical conductive contact members of the back electrode member, and wherein each individual transistor of the array is connected to an individual electrical conductive contact member of the back electrode, whereby potential is selectively addressable to said back electrode contact members to thereby scan and modulate the rotation property of said liquid crystal layer, a light source and means for directing substantially parallel light toward said back electrode member, a first linear polarizer member positioned between said light source and said back electrode member, a second linear polarizer member positioned on the opposite side of said liquid crystal layer with respect to said first polarizer member, said first and second polarizer members oriented in the same direction and a color filter member comprising a plurality of spatially positioned different color filters positioned between said first polarizer member and said back electrode member, in which only one color filter aligned and associated with only one of said back electrode contact members so that only one primary color illuminates that back electrode contact.

2. The system set forth in claim 1 in which said color filter comprises at least a first and second group of filters, said first group of filters transmissive of a first color and second group of filters transmissive of a second color.

3. The system set forth in claim 2 in which said first group of filters comprise a plurality of columns of filters and second group of filters are in columns and positioned between columns of said first group.

4. The system set forth in claim 1 in which said filter members are comprised of a first, second and third group of filters in which said groups are each arranged in columns and in which columns of the first and second groups are disposed between columns of the third group.

5. The system set forth in claim 4 in which said first group of filters transmits only blue light, said second group transmits only red light and said third group transmits only green light.

6. The system set forth in claim 1 in which said liquid crystal layer is a twisted nematic liquid crystal.

7. The system set forth in claim 1 in which said means for selectively addressing said back electrode contact members comprises a plurality of parallel conductor X-bars and parallel conductor Y-bars normal to each other, and insulated from each deposited on said support plate.

8. The system set forth in claim 7 in which one of said thin film transistors of gate type is operatively associated with one of said back electrode contacts and with said X and Y conductors.

9. The system set forth in claim 8 in which said X conductor is connected to the gate of said transistor and the Y-conductor is the source electrode of said transistor and the back electrode contact is the drain electrode of said transistor.

10. A color television display system comprising:

a sealed panel comprising spaced-apart light transmissive insulative front and back support members and peripheral sealing means between the front and back support members, a liquid crystal material filling said sealed panel, which liquid crystal material exhibits the property of rotating the polarization plane of transmitted light in response to application of an electric field across said liquid crystal material, a front electrode disposed on the interior surface of the front support member, which front electrode comprises a layer of electrical conductive material transmissive to light, a back electrode disposed on the interior surface of the back support member, which back electrode comprises a plurality of spaced-apart light transmissive electrical conductive contacts, a thin film transistor array disposed on the interior surface of the back support member between the back electrode contacts, with individual transistors electrically connected to an individual back electrode contact, whereby potential is selectively addressable to the back electrode contacts to thereby scan and modulate the rotation property of the liquid crystal material, a first linear light polarizer disposed on the exterior surface of the back support member, a second linear light polarizer disposed on the exterior surface of the front suppoRt member, with the second polarizer oriented in the same direction as the first polarizer, a color filter member disposed on the exposed surface of the first polarizer and comprising a plurality of spatially positioned different color filters in which individual color filters are aligned and associated with individual back electrode contacts so that only one primary color illuminates the individual back electrode contact, a light source and means proximate the color filter member for directing substantially parallel light through the color filter member.