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Improved dark state electrophoretic display

IP.com Disclosure Number: IPCOM000033723D
Publication Date: 2004-Dec-23

Publishing Venue

The IP.com Prior Art Database

Abstract

Electrophoretic displays switch due to particle migration into a colored fluid. They are a promising technology for development of high-resolution electronic (re-imageable) paper. This paper describes an electrophoretic device that is capable of showing both white and dark state reflectivities. This is achieved by dissolution of a photochromic material into the polymeric binder, which keep together the capsules containing the ink. The photochromic compound is switched with UV light to the colored state. The colored state of the photochromic compound is the same as the color of the dye in the fluid. The dark state of the electrophoretic device in improved (gets darker). Darker translates into increased contrast ration between dark and white states of the device, resulting in improved viewing of the document. The white state is obtained by switching electrophoretic particles on top and isomerisation of the photochromic compound to the colorless state (with Visible light).