Liquid crystal light modulating materials with selectable viewing angles

In a light modulating material comprising microdroplets of liquid crystal dispersed in a light transmissive synthetic resin matrix, the liquid crystal being soluble in the matrix-providing composition and the microdroplets being formed spontaneously by phase separation therefrom, the improvement wherein the ratio of the ordinary index of refraction of the liquid crystal microdroplets to the index of refraction of the matrix is less that one so that when the optical axes of the microdroplets are aligned perpendicular to the surface of the material light is transmitted through viewing-angles oblique to the surface or so that when the optical axes of the microdroplets are aligned at an oblique viewing-angle relative to the surface, light is transmitted through the material at a viewing-angle about the perpendicular to the surface.

In a light modulating material comprising microdroplets of liquid crystal dispersed in a light transmissive synthetic resin matrix, the liquid crystal being soluble in the matrix-providing composition and the microdroplets being formed spontaneously by phase-separation therefrom, the improvement wherein the microdroplets are ellipsoidal with the long axes of the ellipses aligned at an angle oblique to the surface of the material, wherein the optical axes of the microdroplets are aligned generally with the long axes of the ellipses so that in the absence of an applied field light is transmitted through the material at a viewing-angle that generally coincides with the angle of alignment of the optical axes of the microdroplets, and wherein the optical axes of the microdroplets are movable by the application of an external field and the viewing-angle is movable along optical axes of the microdroplets.

A light modulating material comprising at least two sheets of a light transmissive synthetic resin matrix containing dispersed microdroplets of liquid crystal wherein the effective index of refraction of the microdroplets in each sheet is different from the effective index of refraction of the microdroplets in an adjacent sheet.

A light modulating material comprising at least two sheets of a light transmissive synthetic resin matrix containing dispersed microdroplets of liquid crystal wherein the ratio of the index of refraction of the synthetic resin matrix to the ordinary index of refraction of the microdroplets in one sheet differs from the ratio of the index of refraction of the synthetic resin matrix to the ordinary index of refraction of the microdroplets in an adjacent sheet.

A window for selectively scattering away incident light and suitable for use in a vehicle or an architectural structure, the window comprising liquid crystal microdroplets dispersed in a light transmissive synthetic resin matrix, the microdroplets having their extraordinary indices of refraction aligned at a selected angle relative to a planar surface of the matrix, the liquid crystal being soluble in the matrix-forming composition and the microdroplets being formed spontaneously by phase separation therefrom, and the ordinary index of refraction of the microdroplets is deliberately mismatched relative to the index of refraction of the matrix by a selected amount to achieve an effective refractive index such that said material exhibits maximum transparency through a viewing angle which is one of a predetermined angle about a perpendicular to the surface or an angle oblique to the surface, while light incident on same surface at angles other than the viewing angle is primarily diffused or scattered.

A window for selectively scattering away incident light and suitable for use in a vehicle or an architectural structure, the window comprising microdroplets of liquid crystal dispersed in a light transmissive synthetic resin matrix, the microdroplets having their extraordinary indices of refraction aligned at a selected angle relative to a planar surface of the matrix, the liquid crystal being soluble in the matrix-forming composition, the microdroplets being formed spontaneously by phase separation therefrom, and the ordinary index of refraction of the matrix exceeding the refractive index of the microdroplet by a predetermined amount such that light that is incident on the window at a selected angle will be transmitted through the window while incident light at other angles will be diffused or scattered.

A window for selectively scattering away incident light and suitable for use in a vehicle or an architectural structure, the window comprising microdroplets of liquid crystal dispersed in a light transmissive synthetic resin matrix, the microdroplets having their extraordinary indices of refraction aligned at a selected angle relative to a planar surface of the matrix, the liquid crystal being soluble in the matrix-forming composition and the microdroplets being formed spontaneously by phase separation therefrom, and the ordinary index of refraction of the microdroplets being less than the refractive index of the matrix by a predetermined amount such that light that is incident on the window at a selected angle will be transmitted through the window while incident light at other angles will be diffused or scattered.

A window for selectively scattering away incident light and suitable for use in a vehicle or an architectural structure comprising two sheets of a light transmissive synthetic resin matrix containing dispersed microdroplets of liquid crystal wherein the effective index of refraction of the microdroplets in each sheet is different from the effective index of refraction of the microdroplets in an adjacent sheet.

A window for selectively scattering away incident light and suitable for use in a vehicle or an architectural structure comprising two sheets of a light transmissive synthetic resin matrix containing dispersed microdroplets of liquid crystal wherein the ratio of the index of refraction of the synthetic resin matrix to the ordinary index of refraction of the microdroplets in one sheet differs from the ratio of the index of refraction of the synthetic resin matrix to the ordinary index of refraction of the microdroplets in an adjacent sheet.

In a method of making a light modulating material comprising microdroplets of liquid crystal dispersed in a light transmissive synthetic resin matrix, the liquid crystal being soluble in the matrix-providing composition and the microdroplets being formed spontaneously by phase separation therefrom, the improvement comprising the step of adjusting the ratio of the ordinary index of refraction of the liquid crystal microdroplets to the index of refraction of the matrix to a value such that when the microdroplet directors are aligned perpendicular to the surface of the material, incident light is transmitted through the material through a narrow viewing-angle about the perpendicular to the surface or through a viewing-angle oblique to the surface or such that when the microdroplet directors are aligned oblique to the surface of the material, incident light is transmitted through the material at a viewing-angle oblique to the surface or is transmitted through a viewing-angle about the perpendicular to the surface.

In a method of making a light modulating material comprising microdroplets of liquid crystal dispersed in a light transmissive synthetic resin matrix, the liquid crystal being soluble in the matrix-forming composition and the microdroplets being formed spontaneously by phase separation therefrom, the improvement comprising the steps of determining a maximum viewing angle through which light incident to a planar surface of said-material passes through said material, while incident light at other angles is primarily diffused or scattered, and deliberately mismatching the ordinary index of refraction of said microdroplets relative to the index of refraction of said matrix by a selected amount that results in an effective refractive index such that said maximum viewing angle is achieved when the extraordinary indices of refraction of the microdroplets are aligned at a selected angle relative to said surface.

A method of making a light modulating material comprising microdroplets of liquid crystal having positive dielectric anisotropy dispersed in a light transmissive synthetic resin matrix, said liquid crystal being soluble in the matrix-forming composition and said microdroplets being formed spontaneously by phase separation therefrom, the improvement comprising the step of deliberately mismatching the ordinary index of refraction of said microdroplets relative to the index of refraction of said matrix by a selected amount in order to achieve an effective refractive index such that when the extraordinary indices of refraction of the microdroplets are aligned at a selected angle relative to a planar surface of said material light incident to said surface at a predetermined maximum viewing angle passes through said material, while light at other incident angles is primarily diffused or scattered.

A light modulating material comprising liquid crystal microdroplets dispersed in a resin matrix having a generally planar surface, said microdroplets being formed by phase separation and having their optical axes prealigned in a first direction oblique to said surface in the absence of an aligning field, and said material being responsive to an aligning field having a second direction relative to said surface so that the prealigned optical axes of said microdroplets are caused to rotate from said first direction toward said second direction, thereby changing the viewing angle at which light is transmitted through said material.

A light modulating material comprising at least two sheets stacked face-to-face, each of said sheets comprising a resin matrix containing microdroplets of liquid crystal dispersed in said matrix, said microdroplets being formed by phase separation from a solution of liquid crystal and resin upon solidifying of said resin, said material being characterized in that the ratio of the index of refraction of said matrix to the ordinary index of refraction of said microdroplets in one sheet differs from the corresponding ratio in the other sheet, whereby each of said sheets exhibits a different angle of transparency to light incident upon the face thereof, said material exhibiting an overall angle of transparency lying between the different angles of transparency of said two sheets.