Optical conversion method

• US 4,067,043 A
• Filed: 01/21/1976
• Issued: 01/03/1978
• Est. Priority Date: 01/21/1976
• Status: Expired due to Term

• Current Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Original Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Inventors: Perry, William E.
• Primary Examiner(s): Murray, Richard
• Application Number:
  US05/651,007
• Time in Patent Office: 713 Days
• Field of Search: 358/41, 358/43, 358/44, 358/55, 358/225, 358/228, 178/DIG. 29, 350/147, 350/148, 350/159, 350/150, 354/227, 351/25, 351/26, 356/114, 250/225
• US Class Current: 348/361
• CPC Class Codes: H04N 23/10 for generating image signals from different wavelengths
• CPC Class Codes: H04N 23/125 Colour sequential image capture, e.g. using a colour wheel
• CPC Class Codes: H04N 23/55 Optical parts specially adapted for electronic image sensors; Mounting thereof

Abstract

Disclosed is a method for converting an optical system, employing an electrooptic device in conjunction with a pair of crossed polarizing devices, between an activated mode and a deactivated mode. Embodiments in which the optical system is used as a neutral density filter, a selective color filter, or a light shutter, as applied to a television camera are described in which the electrooptic device and the polarizing analyzer are fixed with respect to the television camera, and the first polarizing device is selectively positioned in, or removed from, the optical path of the optical system to activate or deactivate the optical system, respectively. Where the optical system is used as a selective color filter to produce light beams of alternating colors in a field sequential color television system, deactivation of the optical system renders the television a black-and-white system.

Claims

1. The method of selectively activating and deactivating an optical system, which comprises electrooptic means located between crossed polarizing devices comprising first polarizing means and second polarizing means all positioned along a common optical axis, comprising the steps of activating said optical system by positioning said first polarizing means along said optical axis of said optical system so that light incident on said electrooptic means must first pass through said first polarizing means, and deactivating said optical system by removing said first polarizing means from said optical axis of said optical system.

2. The method of selectively activating and deactivating an optical neutral density filter, in combination with a television camera, and comprising an electrooptic device located between crossed polarizing devices comprising a first and second polarizing device all positioned along a common optical axis comprising the steps of activating said optical neutral density filter by positioning said first polarizing device along said optical path of said neutral density filter, and deactivating said neutral density filter by removing said first polarizing device from said optical path of said optical neutral density filter.

3. The method of selectively activating and deactivating a selective color filter, in combination with a television camera, and comprising an electrooptic device located between crossed polarizing devices comprising a first and second polarizing device all positioned along a common optical axis comprising the steps of activating said selective color filter by positioning said first polarizing device along said optical path of said selective color filter, and deactivating said selective color filter by removing said first polarizing device from said optical path of said selective color filter.

4. The method of selectively activating and deactivating a light shutter, in combination with a television camera, and comprising an electrooptic device located between crossed polarizing devices comprising a first and second polarizing device all positioned along a common optical axis comprising the steps of activating said light shutter by positioning said first polarizing device along said optical path of said light shutter, and deactivating said light shutter by removing said first polarizing device from said optical path of said light shutter.

5. The method of switching a television system between a color mode and a black-and-white mode said television system having an optical pickup comprising an electrooptic device located between crossed polarizing devices comprising a first and second polarizing means all positioned along a common optical axis and capable of producing sequential color light signals, comprising the steps of converting said television system to said color mode by placing said first polarizing means along said optical path of said optical signal pickup, and converting said television system to said black-and-white mode by removing said first polarizer from said optical path of said optical signal pickup.