Process for exposure control in microscope cameras and corresponding photomicroscope

US5682567A · kind A · utility

Assignee

• Carl Zeiss Stiftung · DE

Inventors

• Bernd Spruck · Heubach, DE
• Gerhard Herrmann · Schweinfurt, DE

Key dates

• Filing date: Sep 25, 1995
• Grant date: Oct 28, 1997
• Expiry date: Sep 25, 2015

Classification

• Technology area (CPC G): Physics
• CPC primary: G03B7/093
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

Before the exposure of a film, the brightness of the miscroscope image is determined with a sensor by multiple constant (.tau.) which characterizes the dependence of the microscope image with time is determined. The film is subsequently exposed for a single exposure time (D.sub.c) which takes into account the dependence with time of the microscope image. The process is particularly suitable for microphotography of fluorescence pictures with fluorescence which bleaches out (fading). By the display of both the time constant (.tau.) and also the required exposure time, it can be estimated in advance, before exposure of the film, whether the dependence of the fluorescence on time permits microphotography with a sufficient exposure of the film, in the microscope conditions which have been set. A multiple exposure of the film is not required. A photodiode is provided for exposure measurement, and its photocurrent is integrated over time, the integration time being varied in dependence on the exposure measurement signal.