Electrooptic ceramic display and method for making same

• US 4,636,786 A
• Filed: 12/20/1982
• Issued: 01/13/1987
• Est. Priority Date: 12/20/1982
• Status: Expired due to Term

• Current Assignee: CTS Corporation
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Haertling, Gene H.
• Primary Examiner(s): Brigance, Gerald L.
• Assistant Examiner(s): Brier, Jeffery A.
• Application Number:
  US06/450,889
• Time in Patent Office: 1,485 Days
• Field of Search: 350/392, 350/393, 340/783, 340/784, 340/785, 340/756, 340/763
• US Class Current: 345/84
• CPC Class Codes: G02F 1/055 the active material being a ceramic G02F1/035 takes precedence
• CPC Class Codes: G02F 1/0551 Constructional details

Abstract

An improved electrooptic ceramic reflective display is depicted utilizing polished plates of PLZT ceramic materials in a specific arrangement of dual polarizers, PLZT plate, dual transparent electrode patterns deposited on each major surface in precise alignment of the PLZT plate, and a reflecting surface. The display achieves an optimum effect of high contrast of the associated characters, good brightness, wide viewing angle, and minimum operating voltage requirements. When no voltage is applied, the display has a uniform brightness with no characters shown. When a segment, character, or group of characters is activated by applying a selective voltage, a transverse electrooptic effect is electrically induced and a dark character on a light background is depicted. An elastomer Zebra type connector bar is slit and is utilized to facilitate the electrical connections to the top and bottom electrode pads of the PLZT plate as well as to the associated circuitry for the assembled display.

Claims

1. An electrooptic ceramic display comprising:

a first and second polarizer;

a uniaxial transparent ferroelectric ceramic plate having first and second parallel major surfaces, said first and second surfaces disposed contiguous to said first and second polarizers, respectively;

means for inducing first and second electric fields on the first and second surfaces of said plate, respectively, said first and second fields having the same polarity orientation and occupying opposing areas on said first and second surface, said inducing means capable of selectively inducing said first and second fields at a plurality of perdetermined areas on said first and second surfaces; and

a reflector disposed adjacent said first polarizer on a side of the first polarizer opposite said plate.

2. The display according to claim 1 further comprising a light source disposed adjacent said reflector opposite said first polarizer, said reflector being a partial reflector which passes a portion of light emitted by said light source and reflects a portion of the external light entering the display, thereby defining a transflective display.

3. The display according to claim 1 wherein said plate consists of PLZT.

4. The display according to claim 1 wherein said inducing means includes a plurality of electrode groups disposed to induce electric fields to form selectable alphanumeric characters.

5. An electrooptic display comprising:

means for controlling the display of selectable indicia in response to an applied electric field, said controlling means including a first and second polarizer, an electrooptic plate disposed between said first and second polarizers and having first and second major surfaces, first and second sets of electrodes disposed on said first and second surfaces, respectively, said first set of electrodes being in mutual registration with said second set of electrodes, first and second groups of conductors disposed on said first and second surfaces, respectively, and connected to said corresponding first and second sets of electrodes, said first and second groups of conductors disposed opposite each other at an edge of said plate;

an elongate elastomer bar having a plurality of spaced-apart transverse conductive sections and an elongate slit in which said edge of the plate is seated, each conductive section engaging one of the first conductors and an oppositely disposed one of said second group of conductors thereby connecting said first and second groups;

a printed circuit board having a plurality of spaced-apart conductive runners, said bar engaging said printed circuit board, said runners spaced-apart so as to contact correspondingly spaced ones of said conductive sections, whereby each runner is electrically connected to one electrode in said first set and to an electrode in said second set in mutual registration with said one electrode.

6. The display according to claim 5 further comprising a mechanical means for securing said bar to said printed circuit board.

7. The display according to claim 5 further comprising a retaining plate, said retaining plate contiguously engaging a surface of said bar and said printed circuit board contiguously engaging an opposing surface of said bar so that said bar seals said electrooptic plate between said retaining plate and said printed circuit board.