Abstract: A zoom lens device includes a focusing lens group arranged on an object side, and a variator lens group next thereto, and a temperature sensor. The focusing lens group includes a focusing lens, and a temperature-based correction lens for correcting changes in focal point caused by temperature changes around the focusing lens group. The temperature-based correction lens is moved by a temperature-based correction lens driving mechanism along an optical axis to a position determined by a temperature detected by the temperature sensor, independently of the positions of the focusing lens or variator lens group. Thereby, the zoom lens device is capable of favorably correcting defocus of the lens group caused by an ambient temperature change with a simple correcting mechanism.

Abstract: An illumination aperture diaphragm 100A for a light source device for supplying illumination light in an endoscopic device to simultaneously observe a subject image formed by reflected illumination light in the visible light region and a fluorescence image from a fluorescent substance in a subject has a filter region 1 formed in a flat plate-like base material 3 and an aperture region 2 formed inside the filter region 1. The filter region 1 transmits light in the wavelength region of excitation light for allowing the subject to emit fluorescent light and reduces or blocks the transmission of the light in the visible light region that forms the subject image. An illumination aperture diaphragm 200A may include a plurality of diaphragm blade members 20A.

Abstract: A zoom lens device includes a focusing lens group arranged on an object side, and a variator lens group next thereto, and a temperature sensor. The focusing lens group includes a focusing lens, and a temperature-based correction lens for correcting changes in focal point caused by temperature changes around the focusing lens group. The temperature-based correction lens is moved by a temperature-based correction lens driving mechanism along an optical axis to a position determined by a temperature detected by the temperature sensor, independently of the positions of the focusing lens or variator lens group. Thereby, the zoom lens device is capable of favorably correcting defocus of the lens group caused by an ambient temperature change with a simple correcting mechanism.

Abstract: An aperture stop 10A includes a filter area 1 formed on a flat-plate substrate 23, and an aperture area 2 formed inside the filter area 1. The filter area 1 transmits infrared light and reduces or blocks the transmission of visible light. The aperture area 2 transmits light in the wavelength range corresponding to fluorescent light from an observed area of a subject and light in the wavelength range corresponding to illumination light to the subject. The aperture stop 10A does not reduce the light in the wavelength range corresponding to fluorescent light from the observed area of the subject, but variably reduces visible light since the area of the aperture area 2 is variable. Therefore, it becomes possible to simultaneously and clearly observe, with a simple method, a subject image formed by illumination light in the visible light band and an observed image formed by weak fluorescent light from the observed area of the subject in the infrared light band.