Browse Prior Art Database

IMPROVED OPPOSED REFLECTIVE OPTO-COUPLER

IP.com Disclosure Number: IPCOM000005733D
Original Publication Date: 1988-Oct-01
Included in the Prior Art Database: 2001-Oct-31
Document File: 2 page(s) / 91K

Publishing Venue

Motorola

Related People

Clem Brown: AUTHOR

Abstract

A new opto-coupler has been developed (FIG. 1) which offers improved performance over prior art opto- coupler configurations shown in FIG. 2-3.

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MOlORdLA Technical Developments Volume 8 October 1988

IMPROVED OPPOSED REFLECTIVE OPTO-COUPLER

by Clem Brown

A new opto-coupler has been developed (FIG. 1) which offers improved performance over prior art opto- coupler configurations shown in FIG. 2-3.

   Referring to FIGS. 1-3, lead 10 has mounted thereon emitter die E and lead 12 has mounted thereon detec- tordie D. In FIGS. 1-2, leads 10 and 12 are arranged so that emitter E and detector D are in opposed relationship, and in FIG. 3 so as to have a side-by-side relationship. The space surrounding emitter E and detector D is filled with optically transparent die coat 14. Emitter E, detector D and die coat 14 are surrounded by opaque encap- sulant 16.

   The interface between die coat 14 and encapsulant 16 is desirable reflective. It is important that die coat 14 and encapsulant 16 be molecularly bonded as described for example in U.S. Patent 4645,551 to prevent leakage paths developing along the die coat-encapsulant interface.

   The invented device of FIG. 1 achieves improved performance by using a smaller volume of die coat 14 in the region immediately surrounding the opposed emitter-detector die, as compared to the prior art ar- rangements of FIGS 2-3, in combination with a reflective and molecularly bonded die coat-encapsulant inter- face. This enables a larger proportion of light rays 18 emitted by emitter E to reach detector D. Hence, the coupl- ing efficiency and device performance are improved. Further, by ha...