摘要 |
An optical device comprises a first optical system, a second optical system, a shading unit, and a diffraction grating. The first optical system transforms incident light to parallel light. The second optical system transforms incident light to parallel light. An optical axis of the second optical system is different from an optical axis of the first optical system. The shading unit has transmission areas having slit forms and shading areas having strip forms. The transmission areas and the shading areas are alternately arranged. The diffraction grating deflects the light transmitted by the transmission areas in a predetermined direction. Part of the incident light through the first optical system passes through the transmission areas, and the rest are shaded by the shading areas. Part of the incident light through the second optical system passes through the transmission areas, and the rest are shaded by the shading areas.
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