Polaroid Corporation

Cheryl P Petersen

Russell A Gaudiana

Eric S Kolb

Richard T Ingwall

William J Cumming

Alan L Borror

Michael P Filosa

Efthimios Chinoporos

Stephen R Herchen

Electroluminescent devices have, as the active layer, a polymer having a chain comprising a plurality of electroluminescent groupings, adjacent pairs of the electroluminescent groupings being connected via two benzene rings linked to each other only by a single covalent bond, at least one of the benzene rings bearing, at a position ortho to the covalent bond, a substituent of sufficient size that the length of the bond connecting the two benzene rings is not less than 1.495 Angstroms. Preferred electroluminescent groupings comprise a chain of three or more para-phenylene groups connected to one another by amide, carboxy, ester, urea, urethane or vinyl groups. The polymers have a fixed conjugation length with predictable electroluminescent properties.

Electroluminescent devices comprising polymers, and processes for their

Electroluminescent devices have, as the active layer, a polymer having a chain comprising a plurality of electroluminescent groupings, adjacent pairs of the electroluminescent groupings being connected via two benzene rings linked by only a single covalent bond, at least one of the benzene rings bearing, at a position ortho to the covalent bond, a substituent of sufficient size that the two benzene rings are essentially not conjugated with each other. Preferred electroluminescent groupings comprise a chain of three or more para-phenylene groups connected to one another by amide, carboxy, ester, urea, urethane or vinyl groups. The polymers have a fixed conjugation length with predictable electroluminescent properties.

Disclosed is a class of dyes that can be rendered colorless by the application of heat in a silverless imaging system and which have utility in information recording and display, color hard copy and photographic systems. Certain dye ylides, for example, xanthane dye ylides are disclosed which when incorporated in a thin film can be imagewise heated to develop an image by reason of the ylide dye disassociating in the areas where heated and thereby being rendered colorless.

Thermal imaging with ylide dyes

This invention relates to diffusion transfer photographic processes adapted to be performed in the presence of ambient light and to diffusion transfer products useful in such processes wherein enhanced opacification particularly, in the green region of the visible spectrum is achieved by employing a 7-sulfonamido/5- or 6-sulfamoyl indole phthalein as the light-absorbing, pH-sensitive optical filter agent for the shorter wavelength region of the visible spectrum.

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Acton, MA, United States of America

Cheryl P Petersen