Metal Halide High Intensity Discharge Research Articles

Radiative properties of ceramic metal-halide high intensity discharge lamps containing additives in argon plasma

The lighting represents a consumption of about 19% of the world electricity production. We are thus searching new effective and environment-friendlier light sources. The ceramic metal-halide high intensity lamps (C-MHL) are one of the options for illuminating very high area. The new C-MHL lamps contain additives species that reduce mercury inside and lead to a richer spectrum in specific spectral intervals, a better colour temperature or colour rendering index. This work is particularly focused on the power radiated by these lamps, estimated using the net emission coefficient, and depending on several additives (calcium, sodium, tungsten, dysprosium, and thallium or strontium iodides). The results show the strong influence of the additives on the power radiated despite of their small quantity in the mixtures and the increase of visible radiation portion in presence of dysprosium.

Highly Efficient Metal Halide HID Systems With Acoustically Stabilized Convection

High-intensity discharge (HID) lamp systems based on the application of acoustically induced convection, causing arc straightening, enhanced plasma mixing, and effective suppression of segregation effects, are presented. Outstanding HID lamp system properties with significantly enhanced efficacy level up to 150 lm·W-1 providing high-quality white light can be achieved. The design and dimensioning of the ceramic lamp tubes in accordance with high-frequency supply schemes, which enables the system for long-term operation, are discussed.

Observation of vapor pressure enhancement of rare-earth metal-halide salts in the temperature range relevant to metal-halide lamps

Total vapor-phase densities of Dy in equilibrium with a DyI3/InI condensate and Tm in equilibrium with a TmI3/TlI condensate have been measured for temperatures between 900 K and 1400 K. The measurements show strong enhancements in rare-earth vapor densities compared to vapors in equilibrium with the pure rare-earth metal-halides. The measurements were made with x-ray induced fluorescence on the sector 1-ID beam line at the Advanced Photon Source. The temperature range and salt mixtures are relevant to the operation of metal-halide high-intensity discharge lamps.

Atomic transition probabilities of Ce I from Fourier transform spectra

Atomic transition probabilities for 2874 lines of the first spectrum of cerium (Ce I) are reported. These data are from new branching fraction measurements on Fourier transform spectra normalized with previously reported radiative lifetimes from time-resolved laser-induced-fluorescence measurements (Den Hartog et al 2009 J. Phys. B: At. Mol. Opt. Phys. 42 085006). The wavelength range of the data set is from 360 to 1500 nm. Comparisons are made to previous investigations which are less extensive. Accurate Ce i transition probabilities are needed for lighting research and development on metal halide high-intensity discharge lamps.

Radiative lifetimes of neutral cerium

Radiative lifetimes, accurate to ±5%, have been measured for 153 levels of neutral cerium using time-resolved laser-induced fluorescence (TRLIF) on a slow beam of cerium atoms. Of the 153 levels studied, 150 are even parity and 3 are odd parity. The levels range in energy from 16 869 to 28 557 cm−1. This set of Ce I lifetimes is much more extensive than others published to date, and will provide the absolute calibration for a very large set of measured Ce I transition probabilities. Accurate transition probabilities for lines in the visible and ultraviolet are needed both in astrophysics, for the determination of elemental abundances, and by the lighting community, for research and development of metal halide high-intensity discharge lamps.

A survey of infrared continuum versus line radiation from metal halide lamps

Near-infrared radiation (near-IR) losses from the arcs of six commercial metal halide high intensity discharge (MH-HID) lamps with various power levels and with both Na/Sc and rare earth doses were surveyed in this paper. A radiometrically calibrated Fourier transform infrared spectrometer was used. Lamps with rare earth doses have appreciably better color rendering indices (CRIs) than lamps with Na/Sc doses. The ratios of near-IR continuum emission over near-IR line emission from these six lamps were compared. The near-IR continuum dominates near-IR losses from lamps with rare earth doses and the continuum is significant, but not dominant, from lamps with Na/Sc doses. There was no strong dependence of this ratio on input power or color temperature (Tc). Total near-IR losses were estimated using absolutely calibrated, horizontal irradiance measurements. Estimated total near-IR losses were correlated with CRI. The lamps with rare earth doses yield the best CRIs, but have appreciably higher near-IR losses due primarily to continuum processes. One of these rare earth MH-HID lamps was used in a more detailed study of the microscopic physics of the continuum mechanism (Herd M T and Lawler E 2007 J. Phys. D: Appl. Phys. 40 3386).

Infrared continuum radiation from metal halide high intensity discharge lamps

Infrared (IR) continuum radiation from the arc of a metal halide high intensity discharge lamp was measured and modelled. There are three contributions to the near IR continuum from free electrons: electron–Hg atom bremsstrahlung, electron–ion bremsstrahlung and electron–ion recombination radiation. Electron–Hg atom bremsstrahlung is the most important of these. The radiation transport model utilized empirical Hg density, arc temperature and electron density maps. The line width of the Hg 71S0 to 61P1 resonance broadened transition was used to determine the arc core Hg density. The arc temperature as a function of radius was determined using the radiance of the Hg 9860, 7311 and 7166 cm−1 lines. Relative densities of neutral Dy atoms and Dy ions as a function of radius were found using an Abel inversion of the relative line radiance of selected Dy I and Dy II lines. A Saha analysis was used to determine the electron density in the lamp. The continuum is 73% of the total near IR radiation in the 4000–12 800 cm−1 range.

X-ray induced fluorescence measurement of segregation in a DyI3–Hg metal-halide lamp

Segregation of elemental Dy in a DyI3–Hg metal-halide high-intensity discharge lamp has been observed with x-ray induced fluorescence. Significant radial and axial Dy segregation are seen, with the axial segregation characterized by a Fischer parameter value of λ = 0.215 ± 0.002 mm−1. This is within 7% of the value (λ = 0.20 ± 0.01 mm−1) obtained by Flikweert et al (2005 J. Appl. Phys. 98 073301) based on laser absorption by neutral Dy atoms. Elemental I is seen to exhibit considerably less axial and radial segregation. Some aspects of the observed radial segregation are compatible with a simplified fluid picture describing two main transition regions in the radial coordinate. The first transition occurs in the region where DyI3 molecules are in equilibrium with neutral Dy atoms. The second transition occurs where neutral Dy atoms are in equilibrium with ionized Dy. These measurements are part of a larger study on segregation in metal-halide lamps under a variety of conditions.

Infrared losses from a Na/Sc metal-halide high intensity discharge arc lamp

A study of the near-infrared (IR) emission from the arc of a metal-halide high intensity discharge (MH-HID) lamp with a sodium/scandium chemistry is reported. Radiometrically calibrated spectra from 0.7 to 2.5 μm were recorded as a function of position on the arc tube of a 250 W lamp. These spectra were analysed to determine the relative densities of Na and Sc atoms and the arc temperature as a function of radius. Information from these spectra, combined with absorption measurements in the companion paper (Bonvallet and Lawler 2003), were used to determine the absolute output power in the near-IR from the MH-HID lamp.

Optical absorption spectroscopy on a metal-halide high intensity discharge arc lamp using synchrotron radiation

A sensitive, spatially resolved optical absorption spectroscopy experiment using synchrotron radiation on metal-halide high intensity discharge (MH-HID) lamps was performed. This experiment was used to measure the absolute column densities of ground and excited level Sc atoms, ground level Sc+ ions, and ground level Na atoms in a 250 W MH-HID lamp during operation. The column densities were Abel inverted and used to determine the arc temperature as a function of radius and the absolute electron density as a function of radius. Although most of these measurements were made using a one-dimensional spectrally-multiplexed experiment, a two-dimensional spatially and spectrally multiplexed experiment has also been demonstrated. The absolute density and temperature maps from this experiment were used to determine the absolute near-infrared output power from the MH-HID lamp as described in the companion paper (Smith et al 2003).

Automotive HID headlamps producing compact electronic ballasts using power ICs

Incandescent halogen lamps have been the standard for automotive headlamps; however, metal halide high-intensity discharge (HID) lamps have slowly begun to be commercially used since the mid-1990s. The lighting system of the metal halide HID headlamp makes a great contribution to energy savings, longer lamp life and better visibility in traffic zones compared with halogen lamps. (Lamp life is lengthened because it prevents the loss of sodium metal as plus ions through the quartz of the lamp bulb.) This article describes power ICs consisting of full bridge inverters and their drivers in detail. Market requirements for electronic ballasts include more compact size, lighter weight, and lower cost. On the other hand, lamp manufacturers recommend that automotive metal halide HID lamps should be operated at negative voltage potential to the body of automotive headlight fixture in order to lengthen lamp life. In order to meet these requirements, a new multichip power integrated circuit (IC) for electronic ballast of automotive HID headlamps has been developed. Discrete power metal-oxide-semiconductor field-effect transistors (MOSFETs) are used for the inverter of the HID electronic ballast. It contains a high-voltage driver IC including a P-channel lateral double diffused MOSFET (LDMOS) to control the full bridge power MOSFETs.

Discharge lamp using acoustic resonant oscillations to ensure high efficiency

In an electroded metal halide high intensity discharge lamp, the arc is ignited and acoustic resonant oscillations are excited in the fill by a high frequency electrical power supply in order to thoroughly mix the ingredients comprising the fill. Either an amplitude modulated or a non-amplitude-modulated power supply can be used to drive the arc. The result is highly efficient straight arc operation of the lamp even in the horizontal burning position.

Reducing Additive Segregation in Metal Halide High-Intensity Discharge Lamps

Additive segregation in metal halide lamps often reduces lamp efficacy. The author, having ascertained the probable mechanism causing segregation, suggests several parametric changes to reduce segregation and thereby increase lamp efficacy.