Abstract: Low pressure sodium lamp color output is shifted from yellow to a fuller spectral range of visible light (white) by effective simultaneous excitation of sodium and a mercury additive. This is made possible principally by controlling the vapor constituents and the excitation arrangement.

Abstract: A fluorescent lamp (2) having at least two phosphor coatings (12) on the surface of the sealed lamp bulb, typically an inner surface. There is variable driving means which preferentially activates one phosphor and not the other phosphors, at one arrangement or setting or configuration of the driving means, while at another setting the driving means activates in addition a different or several different phosphors. Each phosphors may be a blend of phosphors and the phosphors and/or blends may be overcoated upon one another forming multiple layers or all mixed together and applied as a one layer coating on the lamp surface.

Abstract: A high pressure discharge lamp having a thick film resistor comprising a plurality of resistive elements. A first resistive element is included in a starting circuit for the lamp and a second resistive element is in series with the arc tube during lamp operation for flicker elimination. The integral thick film resistor facilitates mounting and connection of the resistor elements within the lamp envelope. Favorably, the resistor substrate has a surface emissivity of greater than about 0.5, and preferably greater than about 0.9, to provide sufficient radiation cooling within an evacuated outer lamp envelope to prevent resistor failure while keeping the size of the resistor small enough for use as a component in an HID lamp. Additionally, a suitable coating of low vapor pressure thickness covers the solder connecting the metallic resistor terminals to the substrate to prevent evaporation of the solder and its deposition on the inner surface of the outer lamp envelope.

Abstract: A high intensity discharge (HID) lamp includes a resistive fuse for overcurrent protection of its associated ballast, which fuse is connected electrically in series with the discharge vessel of the lamp and continuously dissipates power during lamp operation. The resistive fuse is heated by passage of the operating current through the discharge vessel during lamp operation to a temperature substantially controlled by the operating current. In response to an increase in the operating current to a predetermined overcurrent, the resistive fuse reaches a temperature such that it breaks and disconnects the discharge vessel from its source of electric potential within a predetermined time period. The fuse passes short-term high starting currents and does not disconnect the discharge vessel during each lamp start-up at least until the operating current reaches the predetermined over-current during lamp life.

Abstract: A high pressure discharge lamp having a thick film resistor comprising a plurality of resistive elements. A first resistive element is included in a starting circuit for the lamp and a second resistive element is in series with the arc tube during lamp operation for flicker elimination. The integral thick film resistor facilitates mounting and connection of the resistor elements within the lamp envelope.

Abstract: Two series connected high pressure sodium arc discharge tubes include a saturated arc tube and an unsaturated arc tube. When the saturated arc tube voltage shifts in value due to changes in operating conditions, the other unsaturated arc tube voltage does not shift to compensate for the voltage increase. Because the unsaturated arc tube voltage does not shift, the rate of voltage shift of the saturated arc tube is smaller in magnitude than otherwise would occur if both arc tubes were saturated.

Abstract: A 1000 watt arc discharge arc tube assembly comprises two series connected side-by-side arc discharge tubes whose combined break down voltage in sufficient for a standard 2-5 kv starting pulse to simultaneously start both arc tubes without additional structure. A standard ballast, starter and fixture can be used with the arc tube assembly whose overall length is less than 300 millimeters. The lamps are spaced sufficiently apart to preclude detrimental heat transfer effects on one another and sufficiently close to act as a single source of light in standard fixtures normally employing lamps having a single discharge tube.

Abstract: An HPS sodium vapor discharge lamp having a starting aid consisting essentially of a metallic band disposed circumscribing one end of the lamp discharge vessel, and means for applying a voltage to the metallic bond for inducing ionization throughout the volume of the discharge vessel to facilitate lamp starting. The metallic band may define a heat shield for inhibiting thermal radiation from one end of the discharge vessel.

Abstract: A reflector lamp having an outer reflector envelope filled with a rare gas at a pressure of approximately one atmosphere during lamp operation, a high pressure sodium discharge device within the outer envelope, and support conductors for mounting the discharge device. A sleeve over one of the support conductors helps prevent electrical breakdown through the rare gas.