Optical isolator with encapsulation

Claim 1

An optical isolator which is fabricated upon a lead frame having two side rails, in accordance with a process having the steps of: down setting an LED attachment portion of the lead frame and a photodiode attachment portion of the lead frame to a downset plane substantially parallel to the plane of the side rails and located therebelow a predetermined downset distance; attaching a photodiode die to a photodiode lead of the downset photodiode attachment portion; attaching an LED die to an LED lead of the downset LED attachment portion; rotating one of the attachment portions approximately 180° about an axis in the side rail plane which connects the side rails and thereby positioning the LED die proximate the photodiode die and separated therefrom by an isolation gap substantially equal to twice the downset distance minus the sum of the thicknesses of the LED and photodiode dice; applying a first sheet to a backside of the LED lead opposite the isolation gap; applying a second sheet to a backside of the photodiode lead opposite the isolation gap; filling a cavity between the first and second sheets with an optically transparent material such that the isolation gap is filled with the material; creating an encapsulating body about the optical isolator; and finishing the lead frame protruding from the body.