| 摘要 |
An optical element includes: a base material formed of a film-like resin material that has an infrared absorbing effect; and a multilayered film that adjusts spectral characteristics, and is formed on an object-side surface and an image-side surface of the base material. The optical element is disposed on a light path of an imaging optical system, and of such characteristics that its spectral transmittance, and its spectral reflectivities on the object-side surface and the image-side surface satisfy the conditions (1) to (4) 0.75<TIRCF (600)/TIRCF (540)<0.95  (1) 615<λLT50%<670  (2) |TIRCF (700)/TIRCF (540)|<0.05  (3) 680≦̸λLR50%,  (4) where TIRCF (600), TIRCF (540), and TIRCF (700) are the spectral transmittances of light with wavelength of 600 nm, 540 nm, and 700 nm, respectively, and λLT50% and λLR50% are the wavelengths of near-infrared light at 50% spectral transmittance and 50% spectral reflectivity, respectively. |
