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US 3,944,336 AGranted
Uni-directional viewing system
AssigneeElectron Optics Corporation
InventorW. John Carr, Jr.
Life of this patent
Estimating the term…
Abstract
A uni-directional viewing system with an obliquely disposed mirror defining a beam splitter for partial reflection and partial transmission of a light beam that is generated by a source and having an absorber disposed at one side of the mirror for absorbing the beam that is transmitted through the mirror. The reflected beam is directed towards a viewing port, which is disposed at the other side of the mirror. An eye port, which is disposed on the absorber side of the mirror, is provided for observing a subject at the viewing port. The observed subject views only the image of the source and the observer views the observed subject.
Claims11
An optical system for viewing a subject by a viewer, the viewer being optically concealed from the subject, said system comprising:
- a. an eye port through which the viewer looks;
- b. a viewing port for observing the subject;
- c. source means for generating light, said source means including masking means having randomly distributed shading;
- d. light absorbing means;
- e. means for partially reflecting and partially transmitting said light generated by said source means, said partially reflecting and partially transmitting means interposed between said source means and said light absorbing means;
- f. said partially reflecting and partially transmitting means disposed in a plane that is oblique with respect to a path along which said light is directed from said source means, said plane of said partially reflecting and partially transmitting means being such that light is directed towards said viewing port, the viewer looking into said eye port views the subject, the subject looking into said viewing port observes said light, said light absorbing means operative to prevent said light from being reflected towards the viewer, said masking means operative to camouflage the viewer and his surrounding area.
3 more elements
An optical system for viewing a subject by a viewer, the viewer being optically concealed from the subject, said system comprising:
- a. source means for generating light;
- b. light absorbing means;
- and
- means for partially reflecting and partially transmitting said light generated by said source means, said partially reflecting and partially transmitting means interposed between said source means and said light absorbing means, said partially reflecting and partially transmitting means being transparent mirror means;
- d. said source means including a light source for generating a beam of light, said beam of light directed towards said partially reflecting and partially transmitting means, a translucent sheet interposed between said light source and said partially reflecting and partially transmitting means, said translucent sheet operative to diffuse said beam of light directed towards said partially reflecting and partially transmitting means, and masking means interposed between said translucent sheet and said partially reflecting and partially transmitting means, said masking means having randomly distributed shading;
- e. said transmitted light directed towards said light absorbing means, said reflected light directed towards the subject, the viewer observing the subject through said partially reflecting and partially transmittng means, the subject viewing only said light reflected by said partially reflecting and partially transmitting means, said light absorbing means operative to prevent said transmitted light from being reflected towards the viewer.
3 more elements
An optical system for viewing a subject by a viewer, the viewer being optically concealed from the subject, said system comprising:
- a. a housing;
- b. source means mounted to said housing at one end thereof, said light source generating a beam of light that is directed along a path towards an opposite end of said housing;
- c. a viewing port for the subject mounted to said housing proximate said opposite end thereof;
- d. an observing port for the viewer mounted to said housing proximate said one end thereof, said observing port and said viewing port disposed in planes that are in space parallel relationship wtih a longitudinal axis of said housing;
- and observing port and said viewing port mounted on opposite sides of said housing;
- e. light absorbing means mounted to said housing on said side opposite said observing port at said one end, said light absorbing means disposed in a plane that is in spaced parallel relationship with the plane of said viewing port;
- f. means for partially reflecting and partially transmitting said light generated by said source, said partially reflecting and partially transmitting means mounted to said housing proximate to said one end and disposed in a plane that is oblique to said light path, said partially reflected light directed towards said light absorbing means, said partially transmitted light directed along said light path;
- and
- g. means for reflecting said partially transmitted light towards said viewing port, said reflecting means mounted to said housing proximate to said opposite end and disposed in a plane that is oblique to said light path;
- h. the viewer looking through said observing port views the subject at said viewing port through said partially reflecting and partially transmitting means and said reflecting means, the subject looking through said viewing port observes only said light transmimtted by said partially reflecting and partially transmitting means, said light absorbing means operative to prevent said partially reflected light from being transmitted towards said observing port, said partially reflecting and partially transmitting means being transparent mirror means;
- i. said source means including a light source for generating a beam of light, said beam of light directed towards said transparent mirror means, a translucent sheet interposed between said light source and said transparent mirror means, said translucent sheet operative to diffuse said beam of light, a field of light directed towards said transparent mirror means, and masking means interposed between said translucent sheet and said transparent mirror means, said masking means having randomly distributed shading.
8 more elements
An optical system for viewing a subject by a viewer, the viewer being optically concealed from the subject, said system comprising:
- a. an eye port through which the viewer looks;
- b. a viewing port for observing the subject;
- c. source means for generating light, said source means including masking means through which said light is directed, said masking means having randomly distributed shading, the average spatial frequency of said randomly distributed shading lies within two octaves of the average spatial frequency of a scene defined by the viewer and his surrounding area when viewed through said viewing port;
- d. light absorbing means;
- e. means for partially reflecting and partially transmitting said light generated by said source means, said partially reflecting and partially transmitting means interposed between said source means and said light absorbing means;
- f. said partially reflecting and partially transmitting means disposed in a plane that is oblique with respect to a path along which said light is directed from said source means, said plane of said partially reflecting and partially transmitting means being such that light is directed towards said viewing port, the viewer looking into said eye port views the subject, the subject looking into said viewing port observes said light, said light absorbing means operative to prevent said light from being reflected towards the viewer.
3 more elements
An optical system for viewing a subject by a viewer, the viewer optically concealed from the subject, said system comprising;
- a. a housing mountable in a door, said housing including a viewing port for the subject and an observing port for the viewer, said viewing port and said observing ports located at opposite sides of said housing;
- b. source means mounted to said housing at one end thereof, said source means generating light, said source means including masking means having randomly distributed shading;
- c. light absorbing means mounted to said housing at an opposite end thereof;
- and
- d. means for partially reflecting and partially transmitting said light generated by said source means, said partially reflecting and partially transmitting means mounted to said housing between said source means and said light absorbing means;
- e. said transmitted light directed towards said light absorbing means, said reflected light directed towards said viewing port, the viewer looking through said observing port views the subject at said viewing port through said partially reflecting and partially transmitting means, the subject looking through said viewing port observes only said light reflected by said partially reflecting and partially transmitting means, said light absorbing means operative to prevent said transmitted light from being reflected towards said observing port.
3 more elements
Dependencies are inferred from the claim text.