Projection device for photogrammetrical purposes

US4012136A · kind A · utility

Assignee

• Jenoptik Jena GmbH · DE

Inventors

• Harald de la Croix · Weimar, DE
• Wilfried Muller · Mannenberg, DE

Key dates

• Filing date: Feb 5, 1975
• Grant date: Mar 15, 1977
• Expiry date: Feb 5, 1995

Classification

• Technology area (CPC G): Physics
• CPC primary: G03B21/20
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A projecting device, particularly for use in photogrammetry, employs a Fresnel condensor for illuminating a picture carrier which is imaged through an objective, including a diaphragm, onto a projection table. At least half of the illumination rays entering said objective, is suppressed by said diaphragm. The Fresnel condensor and the severe stopping-down of the objective produce interfering chromatical effects on the projection table. Said chromatical effects are eliminated either by means of a bi- or multifocal embodiment of the Fresnel lens or by insertion of optical means which extend the optical illumination path or by a respective embodiment of the light source.