Volume phase hologram with liquid crystal in microvoids between fringes
AssigneePolaroid Corporation
InventorsRichard T. Ingwall, Mark A. Troll, Duncan H. Whitney
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Abstract
Composite holograms are disclosed wherein microvoids between the holographic interference fringes are filled with a liquid crystal. The diffraction efficiency and other holographic properties of such composite holograms may be varied by external stimuli, e.g., application of an electric field of thermal energy.
Claims20
A volume phase holographic element, in which information is recorded as a pattern of fringes of a material having a different index of refraction than the material between the fringes, characterized in that microvoids between said fringes are at least partially filled with a liquid crystal.
A switchable cell comprising, in sequence, (a) a first transparent support carrying an electrically conductive coating, (b) a volume phase holographic element, in which information is recorded as a pattern of fringes of a material having a different index of refraction than the material between the fringes, wherein microvoids between fringes are at least partially filled with a liquid crystal, and (c) a second transparent support carrying an electrically conductive coating, and means to supply an electric current to said electrically conductive coatings.
A method of forming a composite volume phase holographic element, said method comprising:
- (a) holographically exposing a photosensitive element to record a holographic interference pattern in the form of fringes comprising a material having a different index of refraction than the material between the fringes,
- (b) processing said holographically exposed photosensitive element to form a volume phase holographic element having microvoids between said fringes, and
- (c) imbibing a liquid crystal which has been heated into said volume phase holographic element to at least partially fill said microvoids with said liquid crystal.
A volume phase holographic element, in which information is recorded as a pattern of fringes of a material having a different index of refraction than the material between the fringes, characterized in that the material between the fringes contains a discontinuous, non-scattering distribution of a separate liquid crystal phase.
Dependencies are inferred from the claim text.