摘要 |
Optical apparatus for simultaneously focussing first and second coaxially spaced object planes in respective separate first and second areas of a common image plane 13 (such as the sensor of a CCD camera) comprises non-diffractive beamsplitter means for receiving light from said object planes along a common path 2 for transmission to said first and second image areas along respective first and second optical paths 3, 4, and reflective or transmissive focussing means 8 arranged to bring said first and second object planes into focus in said first and second areas. The object planes may be differentiated by having different length paths 3,4 (different physical lengths and/or using a differential optical delay), and/or by having different focussing powers in the two paths. In an add-on for a camera, differently curved mirrors of long focal length modify the main camera lens. Polarising optics may be used to separate the two images. The apparatus may be used for 3-D imaging or wavefront analysis.
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