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US 6,788,401 B1Granted
Lens testing device and testing sheet
AssigneeSeiko Epson Corporation
InventorsMasashi Kitabayashi, Koichi Kojima
Life of this patent
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AssigneeSeiko Epson Corporation
InventorsMasashi Kitabayashi, Koichi Kojima
Estimating the term…
The present invention provides a lens inspection apparatus and an inspection sheet that make is possible to easily evaluate the resolution of a lens at low cost. A lens inspection apparatus can include an inspection sheet having a test pattern, a sliding holding portion for holding the inspection sheet, a light source for introducing a light beam into the test pattern of the inspection sheet held by the sliding holding portion, a rotary holding portion for holding the sliding holding portion so that the sliding holding portion can rotate in a plane, and a measuring section for capturing an image projected on a screen through the inspection sheet and a projection lens to be inspected, and subjecting the image to image processing. The test pattern has a measuring region in which linear light-shielding portions are arranged in stripes so as to achieve a predetermined spatial frequency. By rotating the rotary holding portion, the resolution of the test pattern, in which the light-shielding portions extend in different directions, can be easily evaluated. Accordingly, the invention makes it possible to simply evaluate the lens resolution at a low cost.
A lens inspection apparatus for inspecting a lens in order to evaluate the resolution of the lens by projecting image light containing a test pattern for resolution measurement onto a screen through the lens, and displaying an image of the test pattern for resolution measurement on the screen, comprising:
A rectangular inspection sheet having a test pattern for resolution measurement on an upper surface thereof, and placed upstream from a lens in an optical path so as to evaluate a resolution of the lens by projecting image light containing the test pattern for resolution measurement onto a screen through the lens and displaying an image of the test pattern for resolution measurement on the screen, the inspection sheet having a measuring region in which a plurality of linear light-shielding portions are arranged continuously in stripes extending between a pair of opposing edges.
Dependencies are inferred from the claim text.