Diffractive optical element
AssigneeMerck Patent GmbH
InventorsStephen Mulcahy, Peter Wyatt, Owain Llyr Parri
Life of this patent
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Abstract
A diffractive optical element comprising at least one achromatic half-wave plate and at least one chromatic half-wave plate, each half-wave plate comprising at least two layers of a polymerized chiral liquid crystal (LC) material on a substrate, wherein at least one of the substrates has a periodic surface grating, a method for its preparation. Also, its use in optical or electrooptical components or devices, especially for digital optics or augmented reality or virtual reality (AR/VR) applications like non-mechanical beam steering elements, optical waveguides, optical couplers, optical combiners, optical deflectors, polarization beam splitters, partial mirrors or lenses.
Claims15
A diffractive optical element (DOE), comprising:
- at least one achromatic half-wave plate (HWP);
- and
- at least one chromatic HWP,
- wherein each HWP comprises a substrate and, provided on the substrate, two or more cholesteric liquid crystal (CLC) layers, the first CLC layer deposited directly on the substrate and the second and further CLC layers deposited directly onto a respective previous CLC layer,
- wherein each CLC layer consists of a polymerized chiral reactive mesogen (RM) mixture, wherein the LC director exhibits a helical twist with a defined twist angle along a helix axis in a thickness direction of the CLC layer, said chiral RM mixture comprising one or more RMs selected from mono-, di and multireactive RMs, and further comprising one or more chiral compounds selected from chiral RMs, and a photoinitiator,
- wherein in at least one of the achromatic HWP or the chromatic HWP the substrate contains a periodic surface grating that induces a rotation of the LC director in an in-plane direction of the first CLC layer.
Dependencies are inferred from the claim text.