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Variable Density Filter Through a Combination of Polarized Filter

IP.com Disclosure Number: IPCOM000045375D
Original Publication Date: 1983-Mar-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Peck, RH: AUTHOR

Abstract

A polarizing filter structure is provided which has two polarizing members in which each member consists of several bands of polarizing material, the bands being arranged in alternate polarizing orientations. Thus, when the first and second members containing such bands are placed on top of each other so that the alternating polarizing bands in each member coincide with each other, there will be a maximum transmission of light. On the other hand, when the two members are moved approximately one band width to a position where the alternating polarizing bands in each layer have polarizing layers of opposite orientation juxtaposed on each other, then light transmission will be minimal. It will be understood that at various points in between during the movement of one band width, we will get various levels of light transmission.

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Variable Density Filter Through a Combination of Polarized Filter

A polarizing filter structure is provided which has two polarizing members in which each member consists of several bands of polarizing material, the bands being arranged in alternate polarizing orientations. Thus, when the first and second members containing such bands are placed on top of each other so that the alternating polarizing bands in each member coincide with each other, there will be a maximum transmission of light. On the other hand, when the two members are moved approximately one band width to a position where the alternating polarizing bands in each layer have polarizing layers of opposite orientation juxtaposed on each other, then light transmission will be minimal. It will be understood that at various points in between during the movement of one band width, we will get various levels of light transmission.

When two polarized filters are similarly oriented, light passes through them. When two polarized filters are in complementary orientation, light passing through the first is blocked by the second filter. The filter structure consists of two layers free to move with respect to one another. Each layer is composed of a large number of bands of a polarizing material. Adjacent bands have complementary orientation. When the two layers are moved with respect to one another in a direction perpendicular to the bands, the light transmitted by the filter structure will vary.

Possible usag...