Liquid-crystal image director for single-lens-reflex camera
First Claim
1. A light-directing mechanism for replacing a hinged mirror in a single-lens-reflex camera, comprising:
- polarizing means for polarizing incident light to provide a beam of polarized incident light,polarization-rotating means for rotating the polarization of said beam of polarized light to provide an output beam from said polarization-rotating means,activating means for activating said polarization-rotating means so that said output beam from said polarization-rotating means is not rotated,a polarizing beam splitter for receiving said output beam from said polarization-rotating means and causing said output beam from said polarization-rotating means to traveling in a first direction when said output beam from said polarization-rotating means is rotated and in a second direction when said output beam from said polarization-rotating means is not rotated,first utilization means for utilizing light traveling in said first direction from said polarizing beam splitter, andsecond utilization means for utilizing light traveling in said second direction from said polarizing beam splitter.
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Accused Products
Abstract
The mirror in a single-lens-reflex (SLR) camera is eliminated by employing a liquid crystal cell and a polarizing beam splitter. The light from an illuminating lamp (32) is linearly polarized in a horizontal direction by a polarizer (58). The polarized illuminating light is totally reflected by a polarizing beam splitter (PBS) (54) and passes through a quarterwave plate (QWP) (56) and an objective lens (36). After passing through QWP (56) for the second time, the light is vertically polarized and totally passes through PBS (54). A focusing lens (40) focuses the image onto a film (30). A voltage supply (46) is connected to a liquid-crystal (LC) cell (44) by an electric switch (52) that can turn LC cell (44) on or off. When LC cell (44) is off, the polarization of the light is rotated by 90° to be horizontally polarized. Thus the light is reflected by another PBS (48) to a prism (24) for viewing by a user (26). When the LC cell (44) is on, the light polarization is not rotated, and the light is transmitted through the PBS (48) to a mechanical shutter (28). During the shutter'"'"'s (28) open period, an intense light pulse from a strobe lamp (42) illuminates a patient'"'"'s eye (38) and exposes film (30). Shutter (28) can be eliminated since the LC cell (44) and the PBS (48) may also function as shutter.
32 Citations
11 Claims
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1. A light-directing mechanism for replacing a hinged mirror in a single-lens-reflex camera, comprising:
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polarizing means for polarizing incident light to provide a beam of polarized incident light, polarization-rotating means for rotating the polarization of said beam of polarized light to provide an output beam from said polarization-rotating means, activating means for activating said polarization-rotating means so that said output beam from said polarization-rotating means is not rotated, a polarizing beam splitter for receiving said output beam from said polarization-rotating means and causing said output beam from said polarization-rotating means to traveling in a first direction when said output beam from said polarization-rotating means is rotated and in a second direction when said output beam from said polarization-rotating means is not rotated, first utilization means for utilizing light traveling in said first direction from said polarizing beam splitter, and second utilization means for utilizing light traveling in said second direction from said polarizing beam splitter. - View Dependent Claims (2, 3, 4)
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5. A light-directing mechanism for replacing a hinged mirror in a single-lens-reflex camera, comprising:
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polarizing means for polarizing incident light to provide a first beam of polarized light, a first polarizing beam splitter for reflecting said first beam of polarized light to provide a reflected beam of polarized light, a quarter-wave plate for causing said reflected beam of polarized light to be circularly polarized to provide a beam of circularly polarized light, imaging means for imaging said beam of circularly polarized light onto an object so that said beam of circularly polarized light is reflected from said object to provide a reflected beam of reverse circularly polarized light so that said reflected beam of reverse circularly polarized light passes through said quarter-wave plate to cause said reflected beam of reverse circularly polarized light to be a second beam of polarized light with polarization perpendicular to the polarization of said first beam of polarized light from said polarizing means so that said second beam of polarized light passes through said first polarizing beam splitter to provide an output beam of polarized light from said first polarizing beam splitter, polarization-rotating means for rotating said output beam from said first polarizing beam splitter to provide an output beam from said polarization-rotation means, activating means for activating said polarization-rotating means so that said output beam from said polarization-rotating means is not rotated, a second polarizing beam splitter for receiving said output beam from said polarization-rotating means and causing said output beam from said polarization-rotating means to travel in a first direction when said output beam from said polarization-rotating means is rotated and in a second direction when said output beam from said polarization-rotating means is not rotated, first utilization means for utilizing light traveling in said first direction from said second polarizing beam splitter, and second utilization means for utilizing light traveling in said second direction from said second polarizing beam splitter. - View Dependent Claims (6, 7, 8, 9)
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10. A light-directing mechanism for replacing a hinged mirror in a single-lens-reflex camera, comprising:
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polarizing means for polarizing incident light to provide a beam of polarized incident light, polarization-rotating means for rotating the polarization of said beam of polarized light to provide an output beam from said polarization-rotating means, activating means for activating said polarization-rotating means so that said output beam from said polarization-rotating means is not rotated, a polarizing beam splitter for receiving said output beam from said polarization-rotating means and causing said output beam from said polarization-rotating means to traveling in a first direction when said output beam from said polarization-rotating means is rotated and in a second direction when said output beam from said polarization-rotating means is not rotated, a viewer for receiving light traveling in said first direction from said polarizing beam splitter, and a portion of film in said camera for receiving light traveling in said second direction from said polarizing beam splitter. - View Dependent Claims (11)
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Specification