Abstract: A dimmer for fluorescent lights utilizes a standard A.C. phase control at normal line A.C. frequencies to control the line power to the standard fluorescent light ballast and thereby control the illumination level of the light. During the "off" time of the A.C. line signal, a high frequency signal is applied to the ballast which supplies additional power through the ballast to the filament of the light but is substantially blocked by the ballast from the discharge portion of the light so does not substantially affect the illuminating output of the light.

Abstract: A shutter system for stage-lighting spotlights includes a housing having a fixed framing gate therein which has an opening therethrough for the passage of light. Two sets of opposing shutter blades are sandwiched, one on each side of the framing gate, between the framing gate and one of a pair of pressure plates which have means urging them toward the framing gate. Each shutter blade has a neck portion which extends through a slot in the housing and which serves as a handle to which pressure may be applied to move the shutter blade. The blades are normally held in place by the action of the pressure plates against the blades and framing gate.

Abstract: A light-collecting reflector for use with a source of light comprises a main reflector having a central parabolic reflecting surface and an outer ellipsoidal reflecting surface surrounding the central surface. The main reflector is adapted to have a source of light placed along its central axis. A secondary reflector having a reflecting surface facing the reflector surfaces of the main reflector and having an open central portion to allow light to pass therethrough, is positioned in front of the main reflector so that light striking the reflector surface of the secondary reflector is reflected back toward the reflecting surfaces of the main reflector. The reflecting surface of the secondary reflector is arcuate with radii that emanate from a circle which is concentric with the center axis of the main reflector.