Lighting apparatus
US5923020A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 26, 1996 |
| Grant date | Jul 13, 1999 |
| Priority date | — |
| Expiry date | Mar 26, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/8806
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A lighting apparatus 1 has a convex lens 11 arranged so that its optical axis is at an angle .theta. with respect to the normal of an observation portion 3a (e.g., a semiconductor substrate or the like), with a camera 5 arranged in the path of the reflected light rays. When a light-emitting portion 13 is arranged along the optical axis of the lens 11, a bright field illumination takes place. If a knob 29 is turned, the light-emitting portion 13 moves along a ball screw 25, thereby changing the illumination from a bright field illumination to a dark field illumination. When a knob 37 is turned, the light exiting the lens 11 will diverge if the light-emitting portion 13 is moved close to the lens 11, converge if the light-emitting portion 13 is moved far away from the lens 11, and be parallel if the light-emitting portion 13 is positioned at the focal point of the lens 11. By changing the position of the light-emitting portion 13 in this way, it is possible to change the illuminating angle and the illuminating angle distribution, and by adjusting the position of the light-emitting portion 13 in accordance with the optical characteristics of the object 3, it is possible to obtain a hi…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.