Phase shifting device and method
US4984893A · kind A · utility
37Cited by
4References
17Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Dec 1, 1989 |
| Grant date | Jan 15, 1991 |
| Priority date | — |
| Expiry date | Dec 1, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/2527
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A phase shifting projector includes an incandescent lamp, a heat-absorbing filter filtering infrared light from the incandescent lamp, a condensing lens receiving light from the filter, a transparent slide having a sinusoidal grating thereon, a projecting lens, a rotatable transparent plate disposed between the slide and the projecting lens, a test surface on which the grating is projected, and a stepper motor connected to the transparent plate for rotating it about an axis generally parallel to a line of the grating to modulate the phase of the grating image projected on the test surface.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.