skip to main content
DOE Patents title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Light intensity compressor

Abstract

In a system for recording images having vastly differing light intensities over the face of the image, a light intensity compressor is provided that utilizes the properties of twisted nematic liquid crystals to compress the image intensity. A photoconductor or photodiode material that is responsive to the wavelength of radiation being recorded is placed adjacent a layer of twisted nematic liquid crystal material. An electric potential applied to a pair of electrodes that are disposed outside of the liquid crystal/photoconductor arrangement to provide an electric field in the vicinity of the liquid crystal material. The electrodes are substantially transparent to the form of radiation being recorded. A pair of crossed polarizers are provided on opposite sides of the liquid crystal. The front polarizer linearly polarizes the light, while the back polarizer cooperates with the front polarizer and the liquid crystal material to compress the intensity of a viewed scene. Light incident upon the intensity compressor activates the photoconductor in proportion to the intensity of the light, thereby varying the field applied to the liquid crystal. The increased field causes the liquid crystal to have less of a twisting effect on the incident linearly polarized light, which will cause an increasedmore » percentage of the light to be absorbed by the back polarizer. The intensity of an image may be compressed by forming an image on the light intensity compressor.« less

Inventors:
 [1]
  1. (Livermore, CA)
Issue Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
OSTI Identifier:
875246
Patent Number(s):
H737
Assignee:
United States of America as represented by United States (Washington, DC) LLNL
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
light; intensity; compressor; recording; images; vastly; differing; intensities; image; provided; utilizes; properties; twisted; nematic; liquid; crystals; compress; photoconductor; photodiode; material; responsive; wavelength; radiation; recorded; placed; adjacent; layer; crystal; electric; potential; applied; pair; electrodes; disposed; outside; arrangement; provide; field; vicinity; substantially; transparent; form; crossed; polarizers; opposite; front; polarizer; linearly; polarizes; cooperates; viewed; scene; incident; activates; proportion; varying; increased; causes; twisting; effect; polarized; percentage; absorbed; compressed; forming; substantially transparent; potential applied; liquid crystals; placed adjacent; light intensities; light incident; crystal material; polarized light; electric field; light intensity; electric potential; liquid crystal; linearly polarized; field applied; recording images; disposed outside; intensity compressor; field causes; /349/

Citation Formats

Rushford, Michael C. Light intensity compressor. United States: N. p., 1990. Web.
Rushford, Michael C. Light intensity compressor. United States.
Rushford, Michael C. Mon . "Light intensity compressor". United States. https://www.osti.gov/servlets/purl/875246.
@article{osti_875246,
title = {Light intensity compressor},
author = {Rushford, Michael C.},
abstractNote = {In a system for recording images having vastly differing light intensities over the face of the image, a light intensity compressor is provided that utilizes the properties of twisted nematic liquid crystals to compress the image intensity. A photoconductor or photodiode material that is responsive to the wavelength of radiation being recorded is placed adjacent a layer of twisted nematic liquid crystal material. An electric potential applied to a pair of electrodes that are disposed outside of the liquid crystal/photoconductor arrangement to provide an electric field in the vicinity of the liquid crystal material. The electrodes are substantially transparent to the form of radiation being recorded. A pair of crossed polarizers are provided on opposite sides of the liquid crystal. The front polarizer linearly polarizes the light, while the back polarizer cooperates with the front polarizer and the liquid crystal material to compress the intensity of a viewed scene. Light incident upon the intensity compressor activates the photoconductor in proportion to the intensity of the light, thereby varying the field applied to the liquid crystal. The increased field causes the liquid crystal to have less of a twisting effect on the incident linearly polarized light, which will cause an increased percentage of the light to be absorbed by the back polarizer. The intensity of an image may be compressed by forming an image on the light intensity compressor.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1990},
month = {1}
}

Patent:

Save / Share: