Resonant piezoelectric chopper for infrared radiation

US4850697A · kind A · utility

Assignee

• Dynatech Electro-Optics Corporation · US

Inventors

• Larry J. Schoennauer · San Luis Obispo, US
• Ronald B. Alers · San Luis Obispo, US
• Keith Kaste · Corona, US
• Ross E. Johnson · Rochester, US
• Jacob Y. Wong · Lompoc, US

Key dates

• Filing date: Mar 16, 1988
• Grant date: Jul 25, 1989
• Expiry date: Mar 16, 2008

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N2021/3174
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Apparatus for inserting and removing several filters from an optical path and for determining at all times the instantaneous positional relationship of each filter with respect to the optical path includes a set of filters mounted on a carrier which is attached to a resonant piezoelectric system, and further includes reference tracks also located on the carrier and extending in the direction of the oscillatory motion and including a sequence of binary indicia progressing in the direction of the oscillatory motion. The reference tracks are read optically to produce a series of binary electrical signals which are processed to yield the instantaneous position of the carrier and filters with respect to a fixed optical path.