Abstract: To cool the diaphragm of a spectral discharge lamp having an anode and a cathode between which a discharge is established, which discharge is controlled by the diaphragm, a fluid supply and removal duct is connected to a cooling circuit in or on the diaphragm structure to supply, for example, water to cool the diaphragm. The tube or bulb of the lamp may be in form of a jacketed enclosure through which cooling water is conducted, preferably in the same supply and removal circuit as that for the diaphragm structure.

Abstract: A light source 2 projects light through a lens system which, preferably, has interchangeable lenses 4, 4', 4" to a conical reflecting body 6 with a reflecting surface 5, from which the light is reflected laterally to a ring reflector 8, to be in turn reflected to an operating field 17 to be illuminated. To permit distance adjustment of the operating room light fixture with respect to the illuminated field 17, a plurality of reflecting bodies 6, 6', with respective reflecting surfaces 5, 5' of different characteristics, for example a ridge surface, concave, conical or the like, are positioned on a drum for selective placement in the beam of light 7 from the lenses. Additionally, the position of the selected reflecting bodies 6, 6' with respect to the light source can be changed by locating the reflecting body on a cam follower and positioning of a camming surface with respect thereto to change the distance between the reflecting body 6 and the light source.

Abstract: To provide for more reliable determination of resistance of sample surfaces to light and weather influences, test apparatus is equipped with a radiation-measuring device. A portion of radiation used for testing is guided to the measuring device, by quartz guides, spectrally dispersed, and measured as to intensity and/or dosage in one or several pre-selected spectral regions. Tests may use natural or artificial radiation, and a measuring device may be stationary or movable relative to a radiation source.

Abstract: A light guide with a liquid light transmissive medium is connected to a variable pressure source, such as a controllable pump, and a hydraulic pressure take-off is connected to the light guide, for example adjacent the light exit window, to control the position of a positionable element, typically an optical system, such as a fluid lens, a movable lens, a diaphragm or the like, with respect to the exit light window from the light guide tube as a function of the pressure applied to the light transmitting liquid within the tube. Thus, the light guide can function simultaneously as a light guide and as a hydraulic servo pressure control element, to control the light output or the position of another element linked to the hydraulic servo positioning piston-cylinder arrangement coupled to the light transmitting fluid in the light guide.