| 摘要 |
An imaging optical system includes: a light control element formed of a dye pigment-containing dichroic guest-host liquid crystal, and that is disposed on a light path to adjust a quantity of incident light for an image sensing device; and an optical filter disposed on the light path, and that includes an infrared absorbing material, the optical filter having a spectral transmittance that satisfies the following conditions (1), (2), and (3) 0.6<TIRCF(580)/TIRCF(540)<1.05   (1) 0.1<TIRCF(640)/TIRCF(540)<0.5   (2) |TIRCF(700)/TIRCF(540)|<0.05   (3) where TIRCF(540), TIRCF(580), TIRCF(640) and TIRCF(700) are the spectral transmittance of the optical filter for the light with a wavelength of 540 nm, 580 nm, 640 nm and 700 nm, respectively. |
