Westinghouse Electric Corporation

North American Philips Lighting Corp.

North American Philips Electric Corp.

Daniel A Larson

William A Thornton

Robert J Zollweg

Edward Chen

Jacob F Michael

A high intensity discharge lamp, for example a high pressure sodium or sodium halide lamp, which utilizes a refractory metal spiral with positive electric potential applied to it positioned around the arc tube to aid in starting and inhibit sodium migration through the arc tube during operation.

High pressure electric discharge lamp employing a metal spiral with

High-intensity-discharge (HID) sodium lamp has a starting aid comprising a conducting ceramic which is hermetically sealed to and extends through an alumina arc tube at least at one end thereof to form an electrically conducting path. The conducting ceramic is fused to the alumina arc tube and is electrically conductive by virtue of having embedded therein a small percentage of finely divided refractory metal. At least during starting, the conducting ceramic is electrically connected through a resistor to the opposite lamp electrode and, as a result, on application of energizing potential, a glow discharge is established between an arc-tube-interior portion of the conducting ceramic and the adjacent electrode to ionize the atmosphere within the arc tube and facilitate lamp starting.

Starting arrangement for high-intensity-discharge sodium lamp

High-intensity-discharge lamp of the mercury-metal halide type efficiently illuminates objects with excellent color appearance. The arc tube filling comprises the usual inert, ionizable starting gas and mercury in predetermined amount as required to provide a predetermined operating voltage drop between the lamp electrodes. The metal halide filling substantially comprises a predetermined limited amount of thallous iodide, a predetermined limited amount of stannous iodide and a predetermined limited amount of calcium iodide. The stannous iodide is used in such amount that it serves primarily to enhance the emission of the calcium iodiode and the amount of stannous iodide is sufficiently limited to curtail the generation of the characteristic continuous tin emission. The calcium iodide is present in greater gram amount than the tin iodide so that the effects of the calcium iodide emission are predominant. The resulting discharge has its emission concentrated in three selected wavelength portions of the visible spectrum, namely, blue violet which is due primarily to the calcium iodide emission, green which is due to the thallium iodide emission, and red which is due to the tin-iodide-enhanced calcium iodide emission. The efficiency of the composite discharge is good and the color appearance of illuminated objects is excellent.

High-intensity-discharge lamp of the mercury-metal halide type which

High-intensity-discharge lamp is fabricated in a fashion generally similar to a standard high-pressure-mercury lamp which has a red-emitting phosphor coated on the outer envelope. In the present lamp, the discharge-sustaining filling in the arc tube is modified to include a small, predetermined proportion of cadmium which adds radiations of a wavelength of about 490 nm to the composite lamp emission. The resulting composite emission has greatly improved color-rendering properties as compared to a similar lamp which does not incorporate the cadmium addition to the arc tube filling.

High-intensity-discharge lamp with improved color rendition of

A metal halide high-intensity discharge lamp for connection to a constant wattage-type mercury ballast including a transformer having a secondary winding having a capacitor in series circuit arrangement therewith. The lamp includes starting aid means and warm-up assistance means to ensure reliable operation. The starting aid means is a voltage doubler comprising a diode and two resistors operating in conjunction with the ballast capacitor and also including a normally closed heat-responsive switch means operative to prevent voltage stress on the diode after the lamp starts. The warm-up assistance means comprises a resistor in series circuit arrangement with the arc tube and a normally open heat-responsive switch means connected in parallel circuit arrangement with the resistor so that during lamp warm up, the resistor reduces the phase shift between the voltage of the lamp and the open circuit voltage of the ballast, thereby increasing the maximum sustaining voltage to the lamp when the lamp current is zero, to prevent the arc from extinguishing.

Resistor-aided starting of metal halide lamps

High-pressure-discharge (HID) sodium lamp has a starting aid comprising a plug-like ceramic member extending through the longitudinal wall of the arc tube proximate one of the lamp electrodes. The plug-like ceramic member is fused to the alumina arc tube and is electrically conductive by virtue of having embedded therein a small percentage of finely divided refractory metal. At least during lamp starting, the plug-like ceramic starting aid is electrically connected through a resistor to the opposite lamp electrode and, as a result, on application of energizing potential, a glow discharge is established between the interior surface of the plug-like ceramic member and the proximate lamp electrode to ionize the atmosphere within the arc tube to facilitate lamp starting.

Starting arrangement for high pressure discharge sodium lamp

A high pressure sodium vapor lamp having an elongated light-transmitting refractory arc tube with closure members sealing each end of the arc tube. An elongated hollow refractory metal member of predetermined length and surface area projects from the arc tube and is sealed through one of the closure members. The interior of the hollow metal member opens into the interior of the arc tube and the projecting end of the hollow metal member is sealed. During the operation of the lamp, the hollow metal member acts as a condensing repository for excess discharge sustaining filling which is not vaporized since the coolest spot of the hollow metal member is at a temperature less than the arc tube. The hollow metal member is provided on the outer surface with a radiation-emissive and electrical-insulating means, and a resistive-heater member is affixed to the exterior of the hollow metal member and in thermal contact with the radiation-emissive and electrical-insulating means. The resistive-heater member generates a predetermined power dissipation when carrying the normal operating current of the lamp to provide a heating effect for the metal member. Voltage rises in the lamp are normally encountered during prolonged operation and typically cause the lamp current to decrease, reducing the heating provided by the resistive-heater member which at least in part compensates for the tendency for increased voltage to be developed across the arc tube.

High pressure sodium vapor lamp with voltage rise compensator

High-intensity-discharge sodium lamp incorporates as a starting gas xenon at a pressure between 50 and 300 torrs, in order to improve the lamp efficiency and the spectral power distribution of the discharge. To facilitate lamp starting on a conventional pulse-type starting circuit, a trigger electrode is wrapped about the exterior of the arc tube proximate one of the lamp electrodes, with the potential applied to the trigger electrode during lamp starting being the same as that which is applied to the other or more remote lamp electrode. The starting pulse applied between the trigger electrode and the proximate lamp electrode initiates the lamp discharge. The trigger electrode also extends along the outer surface of the arc tube contiguous therewith toward the other electrode and the discharge, once initiated, progresses toward the other electrode. If the arc tube is pervious to the migration of sodium ions therethrough under the influence of an electric field during the normal lamp operation, the trigger electrode is effectively removed from the circuit by a switch or a high impedance to prevent such sodium ion migration.

Hid sodium lamp which incorporates a high pressure of xenon and a

A method for securing an electrode to the electrode holder in a high pressure sodium discharge lamp and resulting article, which method, involves spot welding a thin niobium, tantalum or titanium wire across the flattened end of the electrode holder and thereafter spot welding the electrode rod to the electrode holder perpendicular to the axis of the thin wire to provide a strong bond between the electrode and the electrode holder.

Method for mounting electrodes in high pressure sodium lamps and

A high pressure, mercury-vapor (HPMV) discharge lamp of the additive type having a discharge sustaining filling which includes between 0.5 and 2.5 mg. of bismuth iodide (BiI.sub.3) per cubic centimeter of arc tube volume, a mercury charge of about 3.0 mg. per cubic centimeter of arc tube volume and a small quantity of inert ionizable starting gas whereby a substantially continuous radiation spectrum is achieved.

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Cedar Grove, NJ, United States of America

Daniel A Larson