TIR-modulated wide viewing angle display

• US 9,939,707 B2
• Filed: 07/08/2013
• Issued: 04/10/2018
• Est. Priority Date: 07/08/2013
• Status: Active Grant

• Current Assignee: WUXI Clearink Limited
• Original Assignee: Clearink Displays, Inc.
• Inventors: Loxley, Andrew, Pullen, Anthony E., Ng, Boon Chong, Sadlik, Bram M.
• Primary Examiner(s): Phan, James
• Application Number:
  US14/903,547
• Publication Number:
  US 20160147128A1
• Time in Patent Office: 1,737 Days
• Field of Search: 3592221, 359534, 359536, 359227, 359228
• CPC Class Codes: G02B 5/128 transparent spheres being embedded in matrix
• CPC Class Codes: G02F 1/167 by electrophoresis
• CPC Class Codes: G02F 1/16757 Microcapsules
• CPC Class Codes: G02F 1/1676 Electrodes
• CPC Class Codes: G02F 1/1681 having two or more microcells partitioned by walls, e.g. of microcup type
• CPC Class Codes: G02F 1/195 by using frustrated reflection digital reflection using controlled total internal reflection G02F1/315
• CPC Class Codes: G02F 2001/1678 characterised by the composition or particle type
• CPC Class Codes: G09G 2320/068 for control of viewing angle adjustment
• CPC Class Codes: G09G 3/344 based on particles moving in a fluid or in a gas, e.g. electrophoretic devices electrophoretic devices per se G02F1/167

Abstract

Improvements and modifications are provided in the type of frustrated total internal reflection (TIR) systems described in U.S. Pat. Nos. 6,885,496; 6,891,658; 7,286,280; 7,760,417 and 8,040,591. The improvements and modifications include various methods to improve display operation of hemispherical beaded front plane TIR systems such as (a) inhibit or prevent the undesired non-uniform distribution and lateral migration of charged, electrophoretically mobile, TIR frustrating particles by encapsulating or tethering the particles to the beaded front plane surface; (b) inhibit or prevent the settling of the TIR frustrating particles such as modifying the viscosity of the low refractive index medium; and (c) inhibit or prevent the non-uniformity of the applied electric field during display operation such as using a conforming rear electrode.

Claims

1. An image display device comprising:

a reflective sheet having a hemispherical beaded inward surface and an opposed outward surface;

a low refractive index fluid contacting the beaded surface;

a plurality of charged electrophoretically mobile particles suspended in the low refractive index fluid;

means for applying a voltage across the low refractive index fluid to selectively move the particles closely adjacent the beaded surface to frustrate total internal reflection at the beaded surface of light rays passing through the reflective sheet;

a rear support disposed on the opposed side of the low refractive index fluid comprising suspended charged particles from the reflective sheet; and

a plurality of cross-walls extending from the reflective sheet to the rear support and separating the low refractive index fluid into a plurality of micro-cells isolated from one another by the cross-walls,

the low refractive index fluid having an index of refraction sufficiently smaller than the index of refraction of the reflective sheet such that most of the light passing through the reflective sheet undergoes total internal reflection at the beaded surface when the particles are not closely adjacent the beaded surface.

2. An image display device according to claim 1 wherein the cross-walls form a plurality of square shaped micro-cells.

3. An image display device according to claim 1 wherein the cross-walls form a plurality of hexagonal shaped micro-cells.