Contact-free measuring apparatus having an F-theta-corrected, catadioptric objective and method for using the same
AssigneeZumbach Electronic AG
InventorBrian Blandford
Life of this patent
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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.
Claims11
An apparatus for contact-free measurement of an object by means of a telecentric light beam scanning said object, comprising a light source for emitting a light beam, means for deflecting this light beam with an angular velocity, optical means having an optical axis, for transforming said deflected light beam into said telecentric scanning light beam substantially in the direction of said optical axis for scanning said object, said optical means comprising an F-theta corrected objective comprising a meniscus lens adjacent said means for deflecting said beam, the radii of curvature of said meniscus lens effecting a refraction depending on the angle of deflection of said beam, and two catadioptric elements at the side of said meniscus lens opposite to said means for deflecting the light beam, the dimension of each of said catadioptric elements in a direction perpendicular to the optical axis exceeding the dimension of said meniscus lens, reflecting means on each of said catadioptric elements for said beam, said deflected light beam being thereby transformed into a telecentric light beam of which the scanning velocity is proportional to said angular velocity.
An apparatus for contact-free measurement of an object by means of a telecentric light beam scanning said object, comprising a light source for emitting a light beam, means for deflecting this light beam with an angular velocity, optical means having an optical axis, for transforming said deflected light beam into said telecentric scanning light beam substantially in the direction of said optical axis for scanning said object, said optical means comprising an F-theta corrected objective comprising a meniscus lens adjacent said means for deflecting said beam, a first catadioptric element at the side of said meniscus lens opposite to said means for deflecting the light beam, said first catadioptric element having curved surfaces, and a second catadioptric element having plane surfaces at the outlet of said optical means, at least one dimension of each of said catadioptric elements in a direction perpendicular to said optical axis exceeding the dimension of said meniscus lens, and each of said catadioptric elements having reflecting means for said beam said deflected light beam being thereby transformed into a telecentric light beam of which the scanning velocity is proportional to said angular velocity.
An apparatus for contact-free measurement of an object by means of a light beam scanning said object, comprising a light source for emitting a light beam, means for deflecting this light beam substantially in the direction of said optical axis for scanning said object, said optical means comprising an F-theta corrected objective comprising a lens adjacent said means for deflecting said beam, and two catadioptric elements at the side of said lens opposite to said means for deflecting the light beam, the dimension of said catadioptric elements in a direction perpendicular to the optical axis exceeding the dimension of said lens, said deflected light beam being thereby transformed into a telecentric light beam of which the scanning velocity is proportional to said angular velocity, said catadioptric elements being strip-shaped and extending substantially in said deflecting plane, each of said catadioptric elements having an elongated mirror extending along one side thereof and a light transmitting zone extending along the other side thereof, said beam being transmitted through each of said elements at said light-transmitting zone and reflected by said mirror, said deflected beam and said telecentric beam being in parallel planes adjacent each other.
Dependencies are inferred from the claim text.