Patent ID: 8178010

Claim:
A method of producing an optical device having a sub-wavelength grating formed in at least one of a plurality of regions, wherein a light path of an incident light beam having a predetermined polarization direction in the sub-wavelength grating is the same as a light path of the incident light beam in neighboring regions, said method comprising the steps of: fabricating a mold having a fine grating shape on a region of a surface thereof corresponding to the at least one of the plurality of regions, and having neighboring regions without the fine grating shape, said fabricating including selecting the fine grating shape such that the fine grating shape forms a sub-wavelength grating with a refractive index, a grating height or a duty ratio such that a light path of an incident first light beam passing through the sub-wavelength grating is the same as a light path of the first light beam passing through regions neighboring the at least one region, wherein the sub-wavelength grating is not formed in the neighboring regions; arranging a light-transmittive and thermal elastic resin on the surface of the mold and heating the resin to a melting temperature; pressing the heated resin on the mold; cooling the resin gradually after the resin is shaped based on the mold for shape transcription; and releasing the resin from the mold.