Diffractive optical element and method of manufacturing the same
AssigneeCanon Kabushiki Kaisha
InventorsEiichi Murakami, Seiji Takeuchi
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Abstract
The present invention discloses a diffractive optical element whose optical axis can be precisely positioned, and a method of manufacturing the diffractive optical element. The diffractive optical element includes a region provided with a concentric uneven pattern and having a predetermined light bending characteristic, and a peripheral section worked so that the optical axis of the diffractive optical element determined by the light bending characteristic of the region aligns with the center of the profile of the diffractive optical element.
Claims8
A method of manufacturing a diffractive optical element, which is turned by a turntable and has a light-bending function, said method comprising:
- a first step of forming a diffraction grating of the diffractive optical element;
- a second step of detecting the state of light transmitted from a light source through the diffractive optical element while turning the diffractive optical element about a turn axis of the turntable;
- a third step of adjusting relative positions of an optical axis of the diffractive optical element and the turn axis to minimize a detected amount of shift of the light detected by said second step;
- and
- a fourth step of cutting an outer periphery of the diffractive optical element, so that the optical axis of the diffractive optical element aligns with a center of a profile of the diffractive optical element.
A diffractive optical element manufacturing apparatus for manufacturing a diffractive optical element having a diffraction grating formed on a substrate, said apparatus comprising:
- a turning unit adapted to turn the diffractive optical element about a turn axis;
- a detector adapted to detect an offset between the turn axis and an optical axis of the diffraction grating;
- position adjustment unit adapted to adjust relative positions of the turn axis and the diffraction grating based on a detection result provided by said detector;
- and
- a cutter adapted to cut an outer periphery of the diffractive optical element while the diffractive optical element is being turned by said turning unit so that the optical axis of the diffraction grating aligns with a center of a profile of the diffractive optical element.
Dependencies are inferred from the claim text.