Abstract: A method of producing a metal halide arc tube is provided, in which four seals are made in the arc tube body. Electrode assemblies are inserted and the arc tube body is sealed at one end, blocking contamination from that end. A second seal encloses the electrode assembly nearer the first seal. Halide and mercury doses are introduced into the central arc chamber through the open end of the arc tube body. A third seal is made at the open end at a distance from the arc chamber, reducing vaporization of the doses and contamination of equipment. A fourth seal encloses the electrode assembly nearer the third seal. The electrode assemblies are thus protected and a reflective coating may be applied without electrode contamination. The ends of the arc tube body are then removed, exposing the electrodes. The arc tube is thus provided.

Abstract: A method and apparatus for assembling a ceramic metal halide high intensity discharge (HID) lamp is disclosed. The apparatus includes a base adapted to receive a ceramic arc tube body, a movable gauge arm having a first portion contacting an end surface of the arc tube body, an electrode holder for supporting an electrode in contact with a second portion of the gauge arm, and a crimper for securing a stop to the electrode at a position determined by the extent of movement of the gauge arm. The apparatus permits stops to be secured to electrodes, either simultaneously or sequentially, thereby correcting for a length deviation of the arc tube body. As a result, half of the required correction is made on each electrode. Since both electrodes are set to the same insertion length, an arc gap is inherently centered in the arc tube body during assembly.

Abstract: A high pressure discharge lamp utilizing an improved ceramic arctube. The arctube has a ceramic central portion, a first ceramic leg extending from one end of the central portion and in some embodiments a second ceramic leg extending from the other end of the central portion. The arctube has reinforcing means where one or both of the legs joins the central portion to reinforce and strengthen the connection between each leg and the central portion. The reinforcing means is preferably seal glass or a layer of seal glass adjacent a ceramic ring.

Abstract: An interference filter or coating is provided in a predetermined pattern on a lamp envelope. The coating is comprised of alternating layers of high and low index of refraction materials applied to a vitreous outer surface of a lamp envelope. The coating may be geometrically symmetric or asymmetric, continuous or discontinuous with respect to the coating itself or the envelope to which it has been applied. The envelope can be masked prior to deposition of the coating so that removal of the mask leaves the filter in the desired pattern. The preferred process for forming the coating includes forming a boric oxide mask on a portion of the envelope, applying the coating over the mask and removing the coating from masked areas of the envelope by dissolving the mask in an aqueous solution.

Abstract: A lamp-to-light guide coupling arrangement includes an electrodeless high intensity discharge lamp comprising an arc tube with an ionizable fill, and an excitation circuit for electrically exciting the ionizable fill to induce therein a light-producing arc discharge. The coupling arrangement further includes a coupling device comprising a generally tubular, hollow body that has an inlet end for receiving light from the arc discharge and a larger, outlet end. The coupling device further comprises an interiorly directed reflector on a surface of the hollow body for reflecting visible light. Such coupling device is shaped so as to receive light at one solid angle over an area of the inlet end and to transmit light at a smaller solid angle but over a larger area of the outlet end. The coupling device is preferably formed from dielectric material. The reflector preferably comprises a refractory optical interference filter.

Abstract: An interference filter or coating is provided in a predetermined pattern on a lamp envelope. The coating is comprised of alternating layers of high and low index of refraction materials applied to a vitreous outer surface of a lamp envelope. The coating may be geometrically symmetric or asymmetric, continuous or discontinuous with respect to the coating itself or the envelope to which it has been applied. The envelope can be masked prior to deposition of the coating so that removal of the mask leaves the filter in the desired pattern. The preferred process for forming the coating includes forming a boric oxide mask on a portion of the envelope, applying the coating over the mask and removing the coating from masked areas of the envelope by dissolving the mask in an aqueous solution.

Abstract: A simulated load circuit for measuring the impedance of the arc discharge of an electrodeless discharge lamp of the type having an arc tube and an excitation coil for exciting the arc discharge in an ionizable fill contained therein includes: a secondary coil spaced apart from the excitation coil by a distance which is varied in order to vary the coupling coefficient between the secondary coil and the excitation coil; a fixed load resistance coupled to the secondary coil; and a variable matching network coupled in series or parallel with the load resistance, the impedance of the matching network being varied in order to vary the ratio of reactance to resistance of the load circuit. The distance between the secondary coil and the excitation coil is varied, and the impedance of the matching network is varied, until the input impedance of the load circuit is substantially equivalent to the operating impedance of the lamp.

Abstract: A high intensity metal halide arc discharge lamp, such as an electrodeless lamp wherein RF energy is inductively coupled to the arc discharge, contains a halide of neodymium alone or in combination with other metals such as one or more rare earth metals, Na, Cs and is essentially mercury free (i.e., <1 mg per cc of arc chamber volume).

Abstract: A base for an electrodeless arc discharge lamp having an elongated tubular stem extending through an outer envelope pinch or press seal includes a pair of electrically non-conductive members secured in mating relation to define an upper cavity and a lower axial bore. The lamp is mounted in the base with its pinch seal secured in the cavity and its stem extending into the bore. With the base mounted in a fixture, RF energy is coupled into the lamp to excite a starting aid in the stem via a conductive bushing in the bore.

Abstract: An electrodeless discharge lamp comprising an arc tube constructed of a light-transmissive material. An exciting structure surrounds the arc tube and is energizable with radio frequency current to develop an arc discharge. A reflective coating of non-conducting insulating material is disposed on the arc tube wall and is located to reflect light from the arc discharge through the arc tube. The reflective coating and the uncoated portion of the arc tube wall are surrounded by the exciting structure so that light from the arc discharge may reach the reflective coating without blockage by the exciting structure and, following reflection by the coating, travel through the uncoated portion of the arc tube wall.

Abstract: An electrodeless high intensity discharge (HID) lamp arc tube having a stabilized condensate location. The arc tube contains a predetermined location or distortion on the inside surface of the arc tube. The distortion may be a protrusion on the inside surface of the arc tube formed during the arc tube forming process. In operation of the lamp, the non gaseous dose remains condensed substantially in the cold spot region formed by said protrusion so that the arc tube walls remain clear for maximal light output, and the arc tube remains stable and efficacious to substantially higher power than is the case for arc tubes without the distortion.

Abstract: A high intensity electrodeless metal halide arc discharge lamp wherein RF energy is coupled to the arc discharge, contains a halide of praseodymium alone or in combination with other metals such as one or more rare earth metals, Na and Cs and is essentially mercury free (i.e., < 1 mg per cc of arc chamber volume).

Abstract: A simulated load circuit for measuring the impedance of the arc discharge of an electrodeless discharge lamp of the type having an arc tube and an excitation coil for exciting the arc discharge in an ionizable fill contained therein includes: a secondary coil spaced apart from the excitation coil by a distance which is varied in order to vary the coupling coefficient between the secondary coil and the excitation coil; a fixed load resistance coupled to the secondary coil; and a variable matching network coupled in series or parallel with the load resistance, the impedance of the matching network being varied in order to vary the ratio of reactance to resistance of the load circuit. The distance between the secondary coil and the excitation coil is varied, and the impedance of the matching network is varied, until the input impedance of the load circuit is substantially equivalent to the operating impedance of the lamp.

Abstract: An arc stabilization arrangement for a discharge lamp having a light transmissive arc tube containing a fill of gas excitable to a discharge state upon introduction thereto of a drive signal having a predetermined frequency associated therewith, includes a modulating arrangement effective for providing a modulating signal which is imposed onto the drive signal. The modulating signal has a frequency associated therewith which approximates the acoustic resonance of the gases within the fill, such modulating signal frequency being less than the frequency of the drive signal. In one embodiment of the invention the modulating arrangement is an amplitude modulating scheme effective such that a modulating amplitude of greater than about 5% of the amplitude of the drive signal is achieved. In yet a further implementation of the present invention, the frequency of the modulating signal is swept about a range of frequencies so that a varying acoustic resonance frequency can be encompassed by the modulating signal.

Abstract: This electrodeless high intensity discharge lamp including a light-transmissive arc tube having spaced wall portions of dielectric material and a first gaseous fill within the arc tube. An excitation coil about the arc tube is energizable with RF current effective to develop a toroidal arc discharge in the first gaseous fill upon a dielectric breakdown of the fill. A starting container is joined to the arc tube and has an end wall constituted by one of said arc-tube wall portions. A second gaseous fill within the starting container has a dielectric strength lower than that of the first gaseous fill. For initiating the rotoidal arc discharge, we provide an arrangement for producing a dielectric breakdown of the gaseous fill within the starting container that develops into an electric discharge that changes the potential at the end wall in such a manner as to cause a dielectric breakdown of the first gaseous fill.

Abstract: A low-loss L-C circuit arrangement for an electrodeless high intensity discharge (HID) lamp includes an excitation coil having at least one coil turn which is disposed in surrounding relation to the arc tube portion of the HID lamp and is configured in a low profile manner so as to minimize light blockage caused thereby. The L-C circuit arrangement includes a capacitor member having first and second capacitor plates which are electrically and mechanically connected to the excitation coil. The connection between the excitation coil and the capacitor member is made by a pair of connection members integrally formed with the coil turn and capacitor plates from a stock sheet of electrically and thermally conductive material.

Abstract: The fill of a self-extinguishing gas probe starter for an electrodeless high intensity discharge lamp includes a starter fill component which has a relatively low vapor pressure and is substantially inert in the starter fill at ambient temperatures, but which component vaporizes and becomes electronegative as the temperature of the lamp increases, so that the starter fill component attaches electrons of the starting discharge in the gas probe starter and thereby extinguishes the starting discharge after initiation of the arc discharge in the arc tube. As a result, the flow of currents between the gas probe starter and the arc tube, which would otherwise have a detrimental effect on the arc tube wall, is avoided.

Abstract: An electrodeless high intensity discharge (HID) lamp having an arc tube, a starting aid, and an outer jacket all integrally formed of fused quartz, includes an excitation circuit for providing RF energy effective for initiating and maintaining a gas discharge within the arc tube. The arc tube is positioned within the outer jacket such that a minimum space exists between the outer jacket and the arc tube thereby allowing the efficient coupling of such RF energy to the arc tube by means of an excitation coil wound in close proximate location to the arc tube. The starting aid is of a substantially smaller dimension than the arc tube thereby allowing for a second spacing to occur above the arc tube. This second spacing is effective for optimum thermal management of heat generated within the outer jacket. The upper end of the outer jacket has an integrally formed annular groove for receiving an annular support member effective for securing the HID lamp to a lighting fixture.

Abstract: This electrodeless high intensity discharge lamp comprises a light-transmissive arc tube having spaced wall portions of dielectric material and a first gaseous fill within the arc tube. An excitation coil about the arc tube is energizable with RF current effective to develop a toroidal arc discharge in the first gaseous fill upon a dielectric breakdown of the fill. A starting container is joined to the arc tube and has an end wall constituted by one of arc-tube wall portions. A second gaseous fill within the starting container has a dielectric strength lower than that of the first gaseous fill. For initiating toroidal arc discharge, we provide an arrangement for producing a dielectric breakdown of the gaseous fill within the starting container that develops into an electric discharge that changes the potential at end wall in such a manner as to cause a dielectric breakdown of first gaseous fill.

Abstract: A gas probe starter for an electrodeless high intensity discharge (HID) lamp includes a fixed starting electrode for coupling a starting voltage to a chamber which is attached to the outer wall of the arc tube and contains a gas. The gas in the starting chamber, which is preferably at a low pressure relative to that of the arc tube fill, is switched between conducting and nonconducting states corresponding to lamp-starting and normal running operation, respectively. To start the lamp, the starting voltage is applied to the starting electrode, causing a discharge current to flow in the gas chamber which, in turn, results in the capacitive coupling of a sufficiently high voltage to the arc tube in order to initiate an arc discharge therein. After the arc discharge is initiated, the starting voltage is substantially reduced so that the discharge current in the starting chamber is extinguished.