Method and apparatus for electro-optically testing circuits
US5272434A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 18, 1990 |
| Grant date | Dec 21, 1993 |
| Priority date | — |
| Expiry date | Dec 18, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R31/308
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Electro-optical in-circuit testing, especially of large circuits such as those assembled on printed circuit boards, is achieved in an automatic test system by disposing an electro-optical sensor in proximity to the circuit conductors, applying test signals to the circuit under test, and measuring an optical property of the sensor at selected regions thereof corresponding to internal nodes, i.e. test points, of the circuit. The sensor may be an optical probe, having a lens and a layer of electro-optical material which is adapted to be applied to the circuit. The electro-optical material may be either a polymer film or a crystal, the latter requiring a flexible coupling medium on the face applied to the circuit under test. The electro-optical material is provided with a reflective coating on one surface to facilitate a polarimetric measurement made transverse to the plane of the material. Another type of optical probe has a layer of electro-optical material with electrodes on the surface opposite the surface applied to the circuit under test. A polarimetric measurement is made by suitably biasing the electrodes and detecting light that passes through the material parallel to its surf…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.