Abstract: A two-lens device includes two lens portions that are disposed so as to be laterally aligned, a lens case that supports the two lens portions in a state where a convergence point can be adjusted in order to image a subject as stereoscopic images by the two lens portions, and a filter installation portion at which a single circular optical filter covering the entire surface of the subject side of the two lens portions is installed so as to be attachable and detachable through thread connection on the subject side of the two lens portions of the lens case.

Abstract: A method and apparatus is disclosed which minimizes the temperature difference between upper and lower portions of a lamp bulb in an optical unit. A UV-IR cut filter is disposed in a downwardly inclined relationship such that an upper portion thereof is nearer to a discharge lamp than a lower portion thereof so that infrared rays and ultraviolet rays included in light emitted from a lamp bulb and reflected in a forward direction from an upper portion of a reflecting face are reflected toward a lower portion of the reflecting face. As the reflected light from the UV-IR cut filter is illuminated on the lower portion of the reflecting face, the temperature difference between upper and lower portions of the lamp bulb is reduced.