Manufacturing method of diffractive optical elements
AssigneesFusao Ishii, DOCOMO Incorporated
InventorsFusao Ishii, Nakanishi Mikiko, Takahashi Kazuhiko, Abrakawa Yuji, Keiichi Murakami
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Abstract
Manufacturing methods are disclosed to produce DOE, HOE and Fresnel optical elements. These methods enable low cost manufacturing with high precision. The methods include lithography, roll-to-roll imprint and UV-casting.
Claims27
A method for manufacturing a diffractive optical element (DOE) on a substrate coated with a photoresist comprising:
- preparing a plurality of photomasks corresponding to a plurality levels of phase-shift at predestinated locations on the substrate and applying the photomasks on top of the photoresist followed by exposing the photoresist to a plurality of photolithographic exposures;
- developing the photoresist after the photolithographic exposure into a top surface of multiple horizontal levels followed by etching the substrate over the photoresist to form a plurality of top surface levels on the substrate corresponding to the plurality levels of phase-shift at the predestinated locations on the substrate;
- and
- applying isotropic etchants to horizontally etch the substrate for removing fences and sharp corners on top of the substrate.
A method for manufacturing a diffractive optical element (DOE) on a substrate coated with a photoresist comprising:
- preparing a photomask with a pattern of different grayscales corresponding to a plurality levels of phase-shift at predestinated locations on the substrate and applying the photomask on top of the photoresist followed by exposing the photoresist to a photolithographic exposure;
- developing the photoresist after the photolithographic exposure into a top surface of multiple horizontal levels followed by etching the substrate over the photoresist to form a plurality of top surface levels on the substrate corresponding to the plurality levels of phase-shift at the predestinated locations on the substrate;
- and
- applying isotropic etchants to horizontally etch the substrate for removing sharp corners on top of the substrate.
A method for manufacturing a diffractive optical element (DOE) on a substrate coated with a photoresist comprising:
- preparing a photolithographic exposure system with a 2D array of pixels with controllable intensity pattern of projection light corresponding to a plurality levels of phase-shift at predestinated locations on the substrate and exposing the photoresist to the projection light;
- and
- developing the photoresist after the photolithographic exposure into a top surface of multiple horizontal levels.
Dependencies are inferred from the claim text.