Contact-free measuring apparatus having an F-theta-corrected, catadioptric objective and method for using the same

Patent 4792695 Issued on December 20, 1988. Estimated Expiration Date:

July 14, 2006. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

3520586

3667360

3825322

3858046

Cata-dioptric objective lens system
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Inventor: Fujii

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Inventor

Blandford, Brian

Assignee

Zumbach Electronic AG

Application

No. 06/885874 filed on 07/14/1986

US Classes:

250/559.24, Transversal measurement (e.g., width, diameter, cross-sectional area)250/236, Rotary motion250/559.13, With laser source356/640, Single beam scans entire width or diameter359/218, Having six, seven, or eight facets359/742Echelon (e.g., Fresnel lens, etc.)

Examiners

Primary: Nelms, David C.
Assistant: Messinger, Michael

International Class

G02B 17/08 (20060101)

Foreign Application Priority Data

1985-07-24 CH

Abstract

An apparatus for the non-contacting measurement of rod-shaped objects contains a telecentric, F-theta-corrected objective which comprises two catadioptric elements. The first catadioptric element is a Mangin mirror and the second catadioptric element is a plane plate mirror-coated at the front, while a third optical element is a meniscus lens. The use of catadioptric elements permits a simplified and inexpensive form of construction which is also compact, as a result of which objects with large dimensions can be measured quickly and accurately. Such an apparatus serves, in particular, for the continuous control of the production of filament-shaped objects.