Browse Prior Art Database

Polymer Field Stop for Electrooptic Device

IP.com Disclosure Number: IPCOM000081906D
Original Publication Date: 1974-Aug-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Eisenmann, DE: AUTHOR [+2]

Abstract

A polymer film may be applied directly to an electrooptic semiconductor device as a field stop to improve registration, reduce parallax and chromatic aberration. When the film is light absorptive, screening effects are further improved.

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Polymer Field Stop for Electrooptic Device

A polymer film may be applied directly to an electrooptic semiconductor device as a field stop to improve registration, reduce parallax and chromatic aberration. When the film is light absorptive, screening effects are further improved.

The figure shows a semiconductor device 10, either light emitting or photoconductor. A PN junction 12 is included in the device and connected in an electrical circuit by conductors 14 and 16. The conductor 14 is suitably insulated from the junction 12 by an insulating layer 18, that may be pyrolytically, thermally or otherwise formed on the surface of the device 10.

A polymer film 22, typically polyimide, is applied as an overcoat to the conductor and insulating members 14 and 18, respectively. The film 22 is made opaque in the area outside the junction 12. The addition of carbon black of appropriate particle size in the polyimide is chemically stable to ultraviolet or infrared frequency, and thermally stable to curing processes of the polymer carrier.

To prevent a glomeration among the polymer/solvent and a filler, a high- surface area, low-particle size (12 millimicrons), nonconductive channel black made from low-content sulphur is an appropriate additive to the film for the formation of opaque areas.

A process for forming the field stop on the device 10 is as follows:
1) Apply a 18 micron carbon black filled polyimide 22

as an overcoat to the surfaces 14 and 18 of the

device 10.
2) Cur...