Method and apparatus for visually examining an array of objects disposed in a narrow gap
US4686565A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 20, 1985 |
| Grant date | Aug 11, 1987 |
| Priority date | — |
| Expiry date | May 20, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B21/0016
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method of and apparatus for visual inspection of the condition of soldered connections between connector pads of a wiring pattern provided on a circuit board and tips of conductor pins of an IC package mounted thereby on the circuit board. The back, or bottom surface of the circuit board is illuminated by a flood of light to produce diffused, or scattered, light in the gap between the circuit board and the IC package, which diffused light is emitted from the edge of the gap. The emitted light is deflected by a small prism disposed adjacent the edge of the gap into a focusing means, such as a stereoscopic microscope having a long focal distance and an optical axis oriented substantially perpendicularly to the surface of the circuit board. Images of the soldered connections are observeable through the eyepiece of the microscope, or are detected by a photoelectric transducer such as a video camera for display on a video screen.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.