Optical elements having image-forming, color- and polarization-selective reflection and containing cholesteric liquid crystals, and the preparation and use of these elements

Claim 2

A wavelength- and polarization-selective element which forms an optical image, wherein at least one cholesteric liquid crystal is enclosed in the cavity of constant thickness between two light-transmitting substrates having curved surfaces in such a way that the helix axis of the liquid crystal is aligned perpendicular to the curved surface of the light-transmitting substrates; wherein the cholesteric liquid crystal employed comprises at least one polyorganosiloxane.

Claim 3

A wavelength- and polarization-selective element which forms an optical image, wherein at least one cholesteric liquid crystal is enclosed in a cavity of constant thickness between two light-transmitting substrates having curved surfaces in such a way that the helix axis of the liquid crystal is aligned perpendicular to the curved surface of the light-transmitting substrates, wherein the light-transmitting substrate having curved surfaces is the concave side of a first cylindrical lens combined with the convex side of a second cylindrical lens in such a way that the element is in the form of a cylinder segment.

Claim 4

A wavelength- and polarization-selective element which forms an optical image, wherein at least one cholesteric liquid crystal is enclosed in a cavity of constant thickness between two light-transmitting substrates having curved surfaces in such a way that the helix axis of the liquid crystal is aligned perpendicular to the curved surface of the light-transmitting substrates, wherein the light-transmitting substrate having curved surfaces is the concave side of a first cylindrical lens combined with the convex side of a second cylindrical lens in such a way that the element is in the form of a cylinder segment.

Claim 5

A wavelength- and polarization-selective element which forms an optical image, wherein at least one cholesteric liquid crystal is enclosed in the cavity of constant thickness between two light-transmitting substrates having curved surfaces in such a way that the helix axis of the liquid crystal is aligned perpendicular to the curved surface of the light-transmitting substrates; wherein the light-transmitting substrate curved surfaces are the concave side of a first lens combined with the convex side of a second lens in such a way that said cholesteric liquid crystal forms a reflector in the form of a concave mirror.

Claim 6

A wavelength- and polarization-selective element which forms an optical image, wherein at least one cholesteric liquid crystal is enclosed in the cavity of constant thickness between two light-transmitting substrates having curved surfaces in such a way that the helix axis of the liquid crystal is aligned perpendicular to the curved surface of the light-transmitting substrates; wherein the light-transmitting substrate curved surfaces are the concave side of a first lens combined with the convex side of a second lens in such a way that said cholesteric liquid crystal forms a reflector in the form of a concave mirror.

Claim 7

A process for the production of optical elements, comprising (a) applying at least one cholesteric liquid crystal to the curved surface of a light-transmitting substrate optionally having an alignment layer; wherein the liquid crystal and substrate are optionally warmed; and (b) subsequently distributing the cholesteric liquid by applying the curved surface of a second optionally warmed light-transmitting substrate, optionally having an alignment layer; in such a manner so as to form a thin cholesteric liquid crystal film having a constant thickness between the light-transmitting substrates.

Claim 8

A process for the production of optical elements, comprising (a) applying at least one cholesteric liquid crystal to the curved surface of a light-transmitting substrate optionally having an alignment layer; wherein the liquid crystal and substrate are optionally warmed; and (b) subsequently distributing the cholesteric liquid by applying the curved surface of a second optionally warmed light-transmitting substrate, optionally having an alignment layer; in such a manner so as to form a thin cholesteric liquid crystal film having a constant thickness between the light-transmitting substrates.

Claim 9

A wavelength- and polarization-selective element which forms by reflection an optical image, wherein at least one cholesteric liquid crystal is enclosed in a cavity of constant thickness between a first light-transmitting substrate and a second light-transmitting substrate, said first and second light-transmitting substrates each having at least one curved cavity defining surface, in such a way that the helix axis of said liquid crystal is aligned perpendicular to said cavity defining surfaces, at least one of said first and second light-transmitting substrates being of non-uniform thickness; wherein said first and second light-transmitting substrates are lenses individually selected from the group consisting of planoconcave, planoconvex, concaveconvex, concaveconcave, and convexconvex.

Claim 10

A wavelength- and polarization-selective element which forms by reflection an optical image, wherein at least one cholesteric liquid crystal is enclosed in a cavity of constant thickness between a first light-transmitting substrate and a second light-transmitting substrate, said first and second light-transmitting substrates each having at least one curved cavity defining surface, in such a way that the helix axis of said liquid crystal is aligned perpendicular to said cavity defining surfaces, at least one of said first and second light-transmitting substrates being of non-uniform thickness; wherein said first and second light-transmitting substrates are lenses individually selected from the group consisting of planoconcave, planoconvex, concaveconvex, concaveconcave, and convexconvex.

Claim 11

An optical system useful as a beam splitter comprising a wavelength- and polarization-selective element which forms an optical image, wherein at least one cholesteric liquid crystal is enclosed in the cavity of constant thickness between two light-transmitting substrates having curved surfaces in such a way that the helix axis of the liquid crystal is aligned perpendicular to the curved surface of the light-transmitting substrates; wherein the cholesteric liquid crystal employed comprises at least one polyorganosiloxane and a mirror positioned within a portion of a path of incident light impinging upon said element such that light reflected from said liquid crystal contained in said cavity of said element impinges upon said mirror and is reflected away from the path of incident light impinging upon said element.

Claim 12

An optical system useful as a beam splitter comprising a wavelength- and polarization-selective element which forms an optical image, wherein at least one cholesteric liquid crystal is enclosed in the cavity of constant thickness between two light-transmitting substrates having curved surfaces in such a way that the helix axis of the liquid crystal is aligned perpendicular to the curved surface of the light-transmitting substrates; wherein the cholesteric liquid crystal employed comprises at least one polyorganosiloxane and a mirror positioned within a portion of a path of incident light impinging upon said element such that light reflected from said liquid crystal contained in said cavity of said element impinges upon said mirror and is reflected away from the path of incident light impinging upon said element.

Claim 13

A color projection display device capable of producing a multicolored optical image from a stream of parallel white light having a direction of incidence, said device comprising: a first beam splitter comprising a first wavelength- and polarization-selective element which forms an optical image, wherein at least one cholesteric liquid crystal is enclosed in the cavity of constant thickness between two light-transmitting substrates having curved surfaces in such a way that the helix axis of the liquid crystal is aligned perpendicular to the curved surface of the light-transmitting substrates, and a mirror positioned within a portion of said stream of incident light impinging upon said first wavelength and polarization selective element such that light reflected from a liquid crystal reflective surface contained in said cavity of said first wavelength and polarization selective element impinges upon said mirror and is reflected away from the path of incident light impinging upon said wavelength and polarization selective element such that light of a first color and circular polarization is reflected to form a first color reflected stream of polarized light, light of color and polarization other than said color and polarization being transmitted through said first beam splitter as a first color-polarization-removed stream of light; at least a second beam splitter comprising a second wavelength- and polarization-selective element which forms an optical image, wherein at least one cholesteric liquid crystal is enclosed in the cavity of constant thickness between two light-transmitting substrates having curved surfaces in such a way that the helix axis of the liquid crystal is aligned perpendicular to the curved surface of the light-transmitting substrates, and a mirror positioned within a portion of the path of said first color-polarization-removed stream of light impinging upon said second wavelength and polarization selective element such that light reflected from a liquid crystal reflective surface contained in said cavity of said second wavelength and polarization selective element impinges upon said mirror and is reflected away from the path of incident light impinging upon said second wavelength and polarization selective element to form a second color reflected stream of polarized light; a first color image positioned across said first color reflected stream of polarized light such that said first color reflected stream passes through said first color image to form a first color image stream of light; a second color image positioned across said second color reflected stream of polarized light such that said second color reflected stream passes through said second color image to form a second color image stream of light; a first recombiner comprising a third wavelength- and polarization-selective element which forms an optical image, wherein at least one cholesteric liquid crystal is enclosed in the cavity of constant thickness between two light-transmitting substrates having curved surfaces in such a way that the helix axis of the liquid crystal is aligned perpendicular to the curved surface of the light-transmitting substrates, having a mirror positioned in the path of said first color image stream on the side of said third wavelength and polarization selective element having a concave reflective surface defined by said liquid crystal contained in said cavity between said curved surfaces of said substrates such that said first color image stream impinging upon said mirror is directed to said concave reflective surface and is reflected thereby past said mirror to form a first color recombinable image-defining stream; a second recombiner comprising a fourth wavelength- and polarization-selective element which forms an optical image, wherein at least one cholesteric liquid crystal is enclosed in the cavity of constant thickness between two light-transmitting substrates having curved surfaces in such a way that the helix axis of the liquid crystal is aligned perpendicular to the curved surface of the light-transmitting substrates, having a mirror positioned in the path of said second color image stream on the side of said fourth wavelength and polarization selective element having a concave reflective surface defined by said liquid crystal contained in said cavity between said curved surfaces of said substrates such that said second color image stream impinging upon said mirror is directed to said concave reflective surface of said second recombiner and is reflected thereby to form a second color recombinable image-defining stream such that said first color recombinable image-defining color stream is transmitted through said second recombiner and merges with said first color recombinable image-defining stream to form a recombined multicolored image stream.

Claim 14

A color projection display device capable of producing a multicolored optical image from a stream of parallel white light having a direction of incidence, said device comprising: a first beam splitter comprising a first wavelength- and polarization-selective element which forms an optical image, wherein at least one cholesteric liquid crystal is enclosed in the cavity of constant thickness between two light-transmitting substrates having curved surfaces in such a way that the helix axis of the liquid crystal is aligned perpendicular to the curved surface of the light-transmitting substrates, and a mirror positioned within a portion of said stream of incident light impinging upon said first wavelength and polarization selective element such that light reflected from a liquid crystal reflective surface contained in said cavity of said first wavelength and polarization selective element impinges upon said mirror and is reflected away from the path of incident light impinging upon said wavelength and polarization selective element such that light of a first color and circular polarization is reflected to form a first color reflected stream of polarized light, light of color and polarization other than said color and polarization being transmitted through said first beam splitter as a first color-polarization-removed stream of light; at least a second beam splitter comprising a second wavelength- and polarization-selective element which forms an optical image, wherein at least one cholesteric liquid crystal is enclosed in the cavity of constant thickness between two light-transmitting substrates having curved surfaces in such a way that the helix axis of the liquid crystal is aligned perpendicular to the curved surface of the light-transmitting substrates, and a mirror positioned within a portion of the path of said first color-polarization-removed stream of light impinging upon said second wavelength and polarization selective element such that light reflected from a liquid crystal reflective surface contained in said cavity of said second wavelength and polarization selective element impinges upon said mirror and is reflected away from the path of incident light impinging upon said second wavelength and polarization selective element to form a second color reflected stream of polarized light; a first color image positioned across said first color reflected stream of polarized light such that said first color reflected stream passes through said first color image to form a first color image stream of light; a second color image positioned across said second color reflected stream of polarized light such that said second color reflected stream passes through said second color image to form a second color image stream of light; a first recombiner comprising a third wavelength- and polarization-selective element which forms an optical image, wherein at least one cholesteric liquid crystal is enclosed in the cavity of constant thickness between two light-transmitting substrates having curved surfaces in such a way that the helix axis of the liquid crystal is aligned perpendicular to the curved surface of the light-transmitting substrates, having a mirror positioned in the path of said first color image stream on the side of said third wavelength and polarization selective element having a concave reflective surface defined by said liquid crystal contained in said cavity between said curved surfaces of said substrates such that said first color image stream impinging upon said mirror is directed to said concave reflective surface and is reflected thereby past said mirror to form a first color recombinable image-defining stream; a second recombiner comprising a fourth wavelength- and polarization-selective element which forms an optical image, wherein at least one cholesteric liquid crystal is enclosed in the cavity of constant thickness between two light-transmitting substrates having curved surfaces in such a way that the helix axis of the liquid crystal is aligned perpendicular to the curved surface of the light-transmitting substrates, having a mirror positioned in the path of said second color image stream on the side of said fourth wavelength and polarization selective element having a concave reflective surface defined by said liquid crystal contained in said cavity between said curved surfaces of said substrates such that said second color image stream impinging upon said mirror is directed to said concave reflective surface of said second recombiner and is reflected thereby to form a second color recombinable image-defining stream such that said first color recombinable image-defining color stream is transmitted through said second recombiner and merges with said first color recombinable image-defining stream to form a recombined multicolored image stream.