Optical element, imaging apparatus including the element, and method of manufacturing the optical element
AssigneePanasonic Intellectual Property Management Co., Ltd.
InventorsJun Murata, Takamasa Tamura
Life of this patent
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Abstract
A lens is obtained by injection molding. The lens includes a plurality of projections arranged on a surface at a pitch smaller than or equal to a predetermined value to reduce reflection of light with a wavelength equal to or greater than the pitch, and a gate mark formed on an outer periphery of the optical element in the injection molding. A peripheral portion of the surface includes a first region whose circumferential position corresponds to the gate mark, and a second region being adjacent to the first region. A pitch of first projections in the first region is greater than a pitch of second projections in the second region.
Claims7
An optical element obtained by injection molding, the element comprising:
- a plurality of projections arranged on a surface at a pitch smaller than or equal to a predetermined value to reduce reflection of light with a wavelength equal to or greater than the pitch;
- and
- a gate mark formed on an outer periphery of the optical element in the injection molding, wherein:
- the surface includes at least a first region and a second region, the first region being located between the gate mark and the second region,
- at least a part of the first region and a part of the second region has the same distance from an optical axis of the optical element, and
- for a given distance from the optical axis the pitch in the first region is greater than the pitch in the second region.
A method of manufacturing an optical element including projections arranged on a surface at a pitch smaller than or equal to a predetermined value to reduce reflection of light with a wavelength equal to or greater than the pitch, the method comprising:
- preparing a mold provided with recesses corresponding to the projections;
- injecting a melted molding material into a cavity of the mold via a gate;
- and
- solidifying the molding material in the mold, wherein:
- the mold includes at least a first mold region and a second mold region, the first mold region being located between the gate mark and the second mold region,
- at least a part of the first mold region and a part of the second mold region has the same distance from an optical axis of the optical element, and
- for a given distance from the optical axis the pitch in the first mold region is greater than the pitch in the second mold region.
Dependencies are inferred from the claim text.