Electro-optic display and adhesive composition for use therein

• US 6,657,772 B2
• Filed: 06/28/2002
• Issued: 12/02/2003
• Est. Priority Date: 07/09/2001
• Status: Expired due to Term

• Current Assignee: E Ink Corporation (E Ink Holdings Incorporated)
• Original Assignee: E Ink Corporation (E Ink Holdings Incorporated)
• Inventors: Loxley, Andrew L.
• Primary Examiner(s): Epps, Georgia
• Assistant Examiner(s): THOMPSON, TIMOTHY J
• Application Number:
  US10/064,279
• Publication Number:
  US 20030011867A1
• Time in Patent Office: 522 Days
• Field of Search: 359/296, 359/298, 359/245, 359/246, 359/250, 345/85, 349/86
• US Class Current: 359/296
• CPC Class Codes: C08L 33/00 Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 75/04 Polyurethanes
• CPC Class Codes: C08L 83/00 Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 83/04 Polysiloxanes
• CPC Class Codes: C09J 11/04 inorganic
• CPC Class Codes: C09J 11/08 Macromolecular additives
• CPC Class Codes: C09J 9/02 Electrically-conducting adhesives
• CPC Class Codes: G02F 1/1334 based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals
• CPC Class Codes: G02F 1/167 by electrophoresis
• CPC Class Codes: G02F 1/16757 Microcapsules

Abstract

An electro-optic display comprises first and second substrates, and an adhesive layer and a layer of electro-optic material disposed between the first and second substrates. The adhesive layer has a volume resistivity in the range of about 10⁹ to about 10¹¹ ohm cm and comprises a mixture of an adhesive material having a volume resistivity of at least about 5×10¹¹ ohm cm and a filler having a volume resistivity not less than about 10⁷ ohm cm, the filler being present in the mixture in a proportion above its percolation threshold in the adhesive material.

Claims

1. An electro-optic display comprising first and second substrates, and an adhesive layer and a layer of electro-optic material disposed between the first and second substrates, the adhesive layer having a volume resistivity in the range of 10⁹ to 10¹¹ ohm cm and comprising a mixture of an adhesive material having a volume resistivity of at least 5×

10¹¹ ohm cm and a filler having a volume resistivity not less than 10⁷ ohm cm, the filler being present in the mixture in a proportion above its percolation threshold in the adhesive material.

2. An electro-optic display according to claim 1 wherein the adhesive material comprises a pressure sensitive adhesive.

3. An electro-optic display according to claim 2 wherein the pressure sensitive adhesive has a volume resistivity of from 10¹² to 10¹⁵ ohm cm.

4. An electro-optic display according to claim 2 wherein the pressure sensitive adhesive is an acrylate, urethane or silicone-based pressure sensitive adhesive.

5. An electro-optic display according to claim 1 wherein the filler has a volume resistivity of from 10⁸ to 5×

10⁹ ohm cm.

6. An electro-optic display according to claim 1 wherein the filler comprises any one or more of polyethylene glycol, a polyurethane polymer dispersion, an acrylate polymer, diamond, zirconium oxide, silicon carbide and sodium-doped glass.

7. An electro-optic display according to claim 1 wherein the filler comprises from 3 to 50 percent by weight of the adhesive layer.

8. An electro-optic display according to claim 1 wherein the electro-optic medium comprises a rotating bichromal member or electrochromic medium.

9. An electro-optic display according to claim 1 wherein the electro-optic medium comprises an electrophoretic medium comprising a plurality of capsules, each capsule comprising a capsule wall and an internal phase comprising electrically charged particles suspended in a suspending fluid and capable of moving through the fluid on application of an electric field to the electrophoretic medium.

10. An electro-optic display according to claim 9 further comprising a polymeric binder within which the capsules are held.

11. An electro-optic display according to claim 9 further comprising at least one electrode disposed between the electro-optic medium and one of the substrates, this electrode being arranged to apply an electric field to the electro-optic medium.

12. An electro-optic display according to claim 11 comprising two electrodes disposed on opposed sides of the electro-optic medium and between the electro-optic medium and the two substrates, at least one of the electrodes and the adjacent substrate being light-transmissive such that the electro-optic medium can be viewed through the light-transmissive substrate and electrode.