Patent ID: 6327085
Filing Date: 2001-12-04
Classification: G02B,H04N

Abstract:
An optical filter comprising:a first birefringent plate constituting an optical element that spatially divides incident light along a first direction extending perpendicular to a direction in which the incident light advances to achieve two separate light fluxes;a vibrational plane converting plate that changes the vibrational plane of each of the two light fluxes emitted from said first birefringent plate;a second birefringent plate constituting an optical element that spatially divides each of the two light fluxes emitted from said vibrational plane converting plate into two light fluxes along a second direction which is different from said first direction, to achieve a total of four separate light fluxes; andan IR blocking filter constituting an optical element provided between said first birefringent plate and said second birefringent plate, wherein:at least either of said first birefringent plate or said second birefringent plate is constituted of a material with a larger difference between the extraordinary ray refractive index and the ordinary ray refractive index compared to that of quartz, andsaid first birefringent plate and said second birefringent plate are both thinner than said vibrational plane converting plate.