Transmission type diffraction grating
AssigneeNippon Sheet Glass Co., Ltd.
InventorsNaoko Hikichi, Kenichi Nakama
Life of this patent
Estimating the term…
Abstract
A transmission diffraction optical element is presented in which ridges having a roughly rectangular cross-section shape are disposed parallel to each other at a regular pitch at the surface of a substrate. Striped thin-film layers are formed on these ridges and a thin-film layer is inserted between the substrate and the ridges. The thin-film layers are arranged at a regular pitch identical to the regular pitch of the ridges and the thin-film layer does not have a periodic pattern oriented in the same direction as the periodic pattern of the ridges.
Claims11
1-4. (canceled)
A transmission diffraction optical element comprising:
- a substrate layer;
- a plurality of parallel ridge-shaped projections formed in a periodic pattern and disposed on the substrate layer, said ridge-shaped projections having roughly rectangular cross-section shapes perpendicular to a longitudinal axis;
- a plurality of parallel striped thin-film layers with a uniform composition being arranged at a pitch matching a pitch at which said ridge-shaped projections are arranged and with an orientation identical to an orientation of an arrangement of said ridge-shaped projections, said plurality of parallel striped thin-film layers formed parallel to said substrate layer and at a fixed distance from said substrate layer or on a plane parallel to said substrate layer with a boundary surface within said ridge-shaped projections;
- and
- a thin-film layer being disposed parallel to said substrate layer, having a boundary surface either parallel to the surface of said substrate layer or on said substrate layer, and formed with a uniform composition within a plane parallel to said substrate layer, said thin-film layer being formed without a periodic pattern in a direction identical to that of said periodic pattern of said ridge-shaped projections and having wavelength-selective transmission properties;
- wherein said striped thin-film layer is disposed on top surfaces of said ridge-shaped projections and on bottom surfaces of grooves between said ridge-shaped projections.
8-11. (canceled)
A transmission diffraction optical element further comprising:
- a striped thin-film layer disposed on each bottom groove surface between adjacent ridge-shaped projections.
13-14. (canceled)
A transmission diffraction optical element further comprising:
- a first striped thin-film layer disposed on the top surface of each ridge-shaped projection and a second striped thin-film layer disposed on each bottom groove surface between adjacent ride-shaped projections.
(canceled)
Dependencies are inferred from the claim text.