Optical inspection system employing dual path pickup system with single spherical mirror
US4125317A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 26, 1977 |
| Grant date | Nov 14, 1978 |
| Priority date | — |
| Expiry date | Nov 26, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/245
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An optical system having a single spherical mirror for collecting light from two directions combined by a beam splitter after the light has been scattered from the surface of a turbine blade or the like. The spherical mirror is located at an equal optical distance from both the surface of the test specimen and a linear detector array so that it operates at a one-to-one magnification ratio. The linear detector array receives light focused by the mirror along a path folded by the beam splitter. This arrangement is helpful in contouring the surface of a turbine blade near a vertical obstruction such as a shroud of a turbine blade since the collection axes of the pickup legs view the incident spot from different directions. None of the optical elements of the inspection system are located in the plane of movement of the test specimen so that even particularly long items such as a helicopter rotor blade can be contoured. Identical upper and lower optical systems allow both surfaces of the test specimen to be contoured simultaneously. An automatic gain control is provided to adjust the optical modulator so that the effective intensity of the beam incident on the detector array is maintai…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.