Refocusing wavelengths to a common focal plane for electrical trace testing
US6653851B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 24, 2001 |
| Grant date | Nov 25, 2003 |
| Priority date | — |
| Expiry date | Dec 21, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R31/309
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The present invention relates to a method and apparatus for testing electrical traces wherein ultraviolet wavelengths from a laser source and visible wavelengths from a scanning camera are focused to a common focal plane. In a first embodiment of the method and apparatus, the wavelengths are commonly focused using an auxiliary lens having a power sufficient to accommodate the difference between the focusing plane of the ultraviolet laser source and the scanning camera. In a second embodiment, the wavelengths are commonly focused by moving the camera optics of the scanning camera relative to its visible light source. Both of these methods and apparatuses employ a fused silica lens system, avoiding the use of calcium fluoride.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.