System and method for measuring accuracy of focus
US8139138B1 · kind B1 · utility
2Cited by
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27Claims
0Family size
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Key dates
| Filing date | Dec 11, 2008 |
| Grant date | Mar 20, 2012 |
| Priority date | — |
| Expiry date | Oct 9, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B13/32
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A reliable and repeatable accuracy of focus measurement device to measure the focus accuracy of cameras that employ a different light path between the lens and the focusing sensor and between the lens and the film or image sensor. The measurement device includes a frame having a substantially planar front face with a focusing target located thereon, and at least one depth-of-field ruler coupled to the frame with a transverse axis falling within a front face plane and a long axis that is angularly adjustable with respect to the front face plane.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.