Double-sided telecentric measurement objective

US5708532A · kind A · utility

Assignee

• Jos. Schneider Optische Werke Kreuznach GmbH & Co. KG · DE

Inventor

• Rolf Wartmann · Bösinghausen, DE

Key dates

• Filing date: Jun 3, 1996
• Grant date: Jan 13, 1998
• Expiry date: Jun 3, 2016

Classification

• Technology area (CPC G): Physics
• CPC primary: G02B13/22
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A double sided telecentic measurement objective for contactless length measurement in two-dimensional and three-dimensional space. The objective has an image-side optical system consisting of three elements equivalent to those of an object-side optical system but in the reverse order, including a cemented positively refracting lens element turned toward the object of image respectively, a collecting lens spaced by an air gap from the cemented lens, and a dispersive meniscus spaced by an air gap from the collecting lens. The widths of the air gaps between the collecting lenses and the meniscus are substantially greater than the widths of air gaps between the cemented lens elements and the collecting lenses.