Optical collimating device employing cholesteric liquid crystal and a non-transmissive reflector
First Claim
1. An optical collimating apparatus for focussing an image at infinity or at a desired finite distance as viewed by an observer, the image being formed by an image means to include circular polarized image light having components within a predetermined bandwidth and of a first rotary sense of circular polarization, the apparatus comprising:
- a cholesteric liquid crystal element of the type reflective to light within the predetermined bandwidth and of a first rotary sense of circular polarization; and
a non-transmissive optical mirror positioned to receive and reflect the image light to the cholesteric liquid crystal element, reversing the rotary sense of circular polarization in so doing;
whereby the cholesteric liquid crystal element and the optical mirror are arranged and positioned so that image light from the image means is reflected or transmitted by the cholesteric liquid crystal element then received and reflected by the optical mirror with reversal of the rotary sense of the image light components to the choesteric liquid crystal element and into the line-of-sight of the observer.
1 Assignment
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Accused Products
Abstract
An optical collimating device employs an optical (concave) mirror and cholesteric liquid crystal element to collimate and project image light into the line-of-sight of an observer in efficient manner. Image light is generated with light components within a predetermined bandwidth and with a predetermined rotary sense. The image light is directed so that it is reflected by the concave mirror, expanding (collimating) the image light, projecting in onto a cholesteric liquid crystal element that reflects those components of the image light within the bandwidth B and having the proper rotary sense of circular polarization. The cholesteric liquid crystal element substantially reflects the returned image to the observer.
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Citations
25 Claims
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1. An optical collimating apparatus for focussing an image at infinity or at a desired finite distance as viewed by an observer, the image being formed by an image means to include circular polarized image light having components within a predetermined bandwidth and of a first rotary sense of circular polarization, the apparatus comprising:
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a cholesteric liquid crystal element of the type reflective to light within the predetermined bandwidth and of a first rotary sense of circular polarization; and a non-transmissive optical mirror positioned to receive and reflect the image light to the cholesteric liquid crystal element, reversing the rotary sense of circular polarization in so doing; whereby the cholesteric liquid crystal element and the optical mirror are arranged and positioned so that image light from the image means is reflected or transmitted by the cholesteric liquid crystal element then received and reflected by the optical mirror with reversal of the rotary sense of the image light components to the choesteric liquid crystal element and into the line-of-sight of the observer. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An optical collimating apparatus for focussing an image at infinity or at a desired finite distance as viewed by an observer, the image being formed by an image means to include image light having components within a predetermined bandwidth and of a predetermined rotary sense of circular polarization, the apparatus comprising:
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a cholesteric liquid crystal element of the type reflective to light of the predetermined bandwidth and the predetermined rotary sense of circular polarization; and a non-transmissive optical mirror; whereby the cholesteric liquid crystal element and the optical mirror are arranged and positioned so that the image light from the image means is projected onto the cholesteric liquid crystal element, and the components of the image light having the predetermined bandwidth and rotary sense are reflected to the optical mirror to be reflected back to the cholesteric liquid crystal element and into the line-of-sight of the observer. - View Dependent Claims (8)
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9. An optical collimating apparatus for focussing image light into the line-of-sight of an observer for viewing as if at infinity or at a desired finite distance from the observer, the apparatus comprising:
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image means for generating an image having light image components within a predetermined bandwidth and having at lease a first rotary sense; reflecting means positioned to receive the light images from the image means for reflecting the light image components, and for transmitting light images having a second rotary sense opposite from the first rotary sense; and non-transmissive optical means positioned to receive and reflect back to the reflecting means and into the line-of-sight of the observer the light image components reflected by the reflecting means, the optical focussing means including means for reversing the rotary sense of the received image light components. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
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18. A method for optically collimating an image at infinity or at a desired finite distance from an observer, comprising the steps of:
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causing to be incident upon a cholesteric liquid crystal element image light having image light components within a predetermined bandwidth and of a predetermined rotary sense of circular polarization, the cholesteric liquid crystal element being constructed to be reflective to image light components of the predetermined bandwidth and of the predetermined rotary sense; positioning the cholesteric liquid crystal element to reflect said image light components to an optical focussing mirror; positioning a nontransmissive focussing mirror to reflect the image light components back toward said cholesteric liquid crystal element; and transmitting the image light components reflected from the optical focussing mirror to said observer.
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19. An system for collimating and projecting an image into the line of sight of an observer, comprising:
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image generating means for producing the image having at least image light components within a predetermined bandwidth and of first and second rotary sense of circular polarization, the first rotary sense being opposite form the second rotary sense; reflecting means constructed to be transmissive to the image light components within the predetermined bandwidth and of the first rotary sense and to be reflective to the image light components within the predetermined bandwidth and of the second rotary sense; a first optical mirror; and a second optical mirror; whereby the reflecting means is relatively positioned (1) to receive the image and to transmit the image light components within the predetermined bandwidth and of the first rotary sense to the first optical mirror for reflection back to the reflecting means with the rotary sense reversed to reflect the image light components from the first optical mirror into the line of sight of the observer, and (2) to reflect the image components from the image source within the predetermined bandwidth and of the second rotary sense to the second optical mirror for reflection back to the reflecting means with reversal from the second rotary sense to the first rotary sense to transmit the image light components from the second optical mirror into the line of sight of the observer. - View Dependent Claims (20, 21, 22, 23, 24, 25)
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Specification