US 4,125,843 AGranted

Method and apparatus for recording and projecting images

AssigneeThe Singer Company

InventorClyde M. Whitby

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Abstract

A single projector and a laser radiation deflecting means enable laser generated images to be projected onto a screen together with a laser pointer. A first laser beam polarized in a first plane and a second laser beam polarized in a second plane is projected into a polarizer cube wherein the first laser beam is reflected to a record medium to record images thereon and the second laser beam is transmitted through the polarizer cube. Polarization and deflecting means located in the path of the transmitted second laser beam changes the polarization of the second laser beam to the polarization of the first laser beam and reflects the second laser beam back into the polarizer cube wherein the second laser beam is reflected in a direction opposite to that of the first laser beam to enable the second laser beam to function as a pointer. By backlighting the record medium with illumination radiation polarized in the second plane, the images recorded on the record medium can be projected onto a screen together with the laser pointer. Illumination radiation polarized in the second plane is obtained from unpolarized illumination by focusing the unpolarized illumination radiation into a polarizer cube to convert the single beam of unpolarized radiation into a first beam of radiation polarized in the second plane and a second beam of radiation polarized in the first plane. By changing the polarization of the second beam of radiation to polarization in the second plane, both the first and second beams of polarized, illumination radiation can be utilized to backlight the record medium to project the image(s) recorded therein.

A recording and projection system comprising;

a projection lens having a projection axis,
image recording medium located at the object plane of said projection lens and positioned substantially perpendicular to said projection axis,
said recording medium normally having an opaque state that is changed into a transparent state where exposed to focused laser radiation,
a polarizer cube located between said recording medium and said projection lens and along said projection axis for reflecting light that is polarized in a first plane and transmitting light that is polarized in a second plane,
a first laser providing laser radiation polarized in said first plane,
a second laser providing laser radiation polarized in said second plane,
means for selectively deflecting said laser radiation from said first and second lasers and directing said deflected radiation into said polarizer cube in a direction substantially perpendicular to said projection axis,
said laser radiation polarized in said first plane being deflected by said polarizer cube to said recording medium to record an image therein,
said laser radiation polarized in said second plane being transmitted thru said polarizer cube,
polarizing and reflecting means interposed in the path of said radiation polarized in said second plane and transmitted through said polarizer cube for causing the polarization of said transmitted laser radiation to be polarized in said first plane and reflecting said transmitted radiation back into said polarizer cube,
said radiation polarized in said second plane and reflected back through said polarizer cube being reflected by said polarizer cube to pass through said projection lens along said projection axis,
a source of illumination radiation polarized in said second plane located behind said recording medium for projecting said images recorded on said recording medium through said polarizer cube and said projection lens along said projection axis.

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Abstract

Claims11