Patent ID: 8045043

Claim:
An imaging device comprising: a lens ( 21 ); an optical module ( 10 ), wherethrough light from the lens ( 21 ) transmits; a first polarizer ( 22 ) for adjusting the polarization plane of the light entering into the optical module ( 10 ); a second polarizer ( 23 ) for polarizing and separating the light being emitted from the optical module ( 10 ); and a photodetector ( 24 ) for detecting light emitted from the second polarizer ( 23 ), wherein the optical module ( 10 ) comprises: a first plate-like optical element ( 4 ) formed with a ¼ wavelength plate portion ( 1 ) and a −¼ wavelength plate portion ( 2 ), the ¼ wavelength plate portion ( 1 ) and the −¼ wavelength plate portion ( 2 ) alternately being jointed together at a joint portion ( 3 ); and a second plate-like optical element ( 8 ) formed with a ¼ wavelength plate portion ( 5 ) and a −¼ wavelength plate portion ( 6 ), the ¼ wavelength plate portion ( 5 ) and the −¼ wavelength plate portion ( 6 ) alternately being jointed together at a joint portion ( 7 ), wherein the first optical element ( 4 ) and the second optical element ( 8 ) are parallel, wherein the ¼ wavelength plate portion ( 1 ) of the first optical element ( 4 ) and the −¼ wavelength plate portion ( 6 ) of the second optical element ( 8 ) are overlapped across a gap ( 9 ), and wherein the −¼ wavelength plate portion ( 2 ) of the first optical element ( 4 ) and the ¼ wavelength plate portion ( 5 ) of the second optical element ( 8 ) are overlapped across the gap ( 9 ), or wherein the optical module ( 10 ) comprises: a first plate-like optical element ( 4 ) formed with a ¼ wavelength plate portion ( 1 ) and a −¼ wavelength plate portion ( 2 ), the ¼ wavelength plate portion ( 1 ) and the −¼ wavelength plate portion ( 2 ) alternately being jointed together at a joint portion ( 3 ); and a second plate-like optical element ( 8 ) formed with a ¼ wavelength plate portion ( 5 ) and a −¼ wavelength plate portion ( 6 ), the ¼ wavelength plate portion ( 5 ) and the −¼ wavelength plate portion ( 6 ) alternately being jointed together at a joint portion ( 7 ), wherein the first optical element ( 4 ) and the second optical element ( 8 ) are parallel, wherein the ¼ wavelength plate portion ( 1 ) of the first optical element ( 4 ) and the ¼ wavelength plate portion ( 5 ) of the second optical element ( 8 ) are overlapped across a gap ( 9 ), and wherein the −¼ wavelength plate portion ( 2 ) of the first optical element ( 4 ) and the −¼ wavelength plate portion ( 6 ) of the second optical element ( 8 ) are overlapped across the gap ( 9 ).