Lamp Life Research Articles

FT-IR Diagnostics of Tungsten-Halogen Lamps: Role of Halogen Concentration, Phosphorus, Wall Material, and Burning Environment

A 24 factorial design matrix experiment is conducted to measure the effects of four different parameters on the HBr and CO levels in tungsten-halogen lamps as a function of burn time. The two gas species are measured at room temperature with the use of Fourier Transform Infrared (FT-IR) spectroscopy. The four parameters varied are (1) initial halogen concentration (as CH3Br); (2) presence or lack of phosphorus; (3) bulb wall material; and (4) burning environment. The effects of these parameters on lamp efficacy and life are also analyzed. In addition, separate oven results show that a small amount of HBr is initially adsorbed onto the bulb surfaces. Also, results are given for separate CO measurements over a wider range of initial CH3Br fill for bulbs with and without phosphorus.

LTE and near-LTE lighting plasmas

High-pressure mercury lamps, metal halide arc lamps, high-pressure sodium lamps, xenon short-arc lamps, xenon flashlamps, and microwave-excited metal halide lamps are extremely important commercial applications of LTE and near-LTE plasma physics. The author outlines in very brief form the basic plasma science in such light sources. The factors controlling the power balance and the luminous efficacy of such sources are discussed. Current research in modeling these complex plasma devices is described. This has reached the stage that successful CAD models are available for new-product design in mercury and high-pressure sodium lamps, but not yet for metal halide lamps. The behavior of electrodes is discussed as an important practical determinant of lamp life. Directions of future research and development are briefly discussed. >

Phase-resolved thermal modeling of a fluorescent lamp electrode as a function of current waveshape and frequency

A modeling technique for calculations of approximate phase resolved temperature profiles of a fluorescent lamp electrode is presented. Analytical expressions for instantaneous electrode temperature are derived by solving a set of simplified differential equations describing time domain electrode temperature dynamics. The electrode surface temperature fluctuations are a function of current waveshape and its operating frequency. The model shows that moderate temperature fluctuations may indicate the safe operating conditions as far as lamp life expectancy is concerned.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Lighting device for medical endoscopes

The author relates approaches to enhancing the effectiveness and safety of the lighting system of endoscopes. The optical and structural diagrams of the lighting unit for endoscopes have been devised. Pilot items of the lighting units based on an illuminating lamp 15-150, intended for flexible and rigid endoscopes of new generation have been manufactured. The unit provides for increasing the life of low-voltage filament lamp as well as for their work in the nominal mode within the range of the mains voltage fluctuations +/- 10% over the whole life.

Modulation of subminiature tungsten-halogen lamps

Halfwave rectified 60 Hz powering of subminiature tungsten-halogen lamps can give 35% brightness modulation in the near IR with no reduction in lamp life.

バランサーを用いた2灯並列式直列インバータにおけるランプ寿命検出の一検討

バランサーを用いた2灯並列式直列インバータにおけるランプ寿命検出の一検討

A Human Factors Evaluation of Freeway Guide Sign Lighting Systems

The objective of the study was to identify a lighting system for freeway guide signs which is more economical and which adequately satisfies motorist's needs in terms of legibility, illumination, color rendition, and other factors. Through the use of technical data and specification review, photometric tests, and computer analyses, ten lighting systems were selected for field testing (10–14 months). Luminance levels, power consumption, maintenance requirements, and lamp life were noted. A human factors study determined legibility distance and rated viewing comfort, lighting uniformity, and color rendition. Senior citizens and young adults were used to detect possible age-related differences. None were noted other than seniors placed more importance on color rendition. It was determined that the differences between the best human factors performing lighting systems and the best regarding economics was only marginal concerning human factors. The most economical system was thus recommended.

SAVING TIME IN TESTING LIFE

By using only the median and the shortest life in statistical analysis, the time required to predict performance from a test is accelerated. This article describes how the method was used successfully for saving time in testing life of incandescent lamps; however, this method is just as applicable to many other products.

Should We Turn Off the Lights When Leaving?

“Since the cost of power saved by turning lamps off may be over-balanced by the cost of shorter lamp life, it may not pay to turn them off for very short periods” [Potter and Roehr 1964]. We developed a decision model to rationally determine whether a policy exhorting facility users to switch off lights is optimal. This model determines the balance between electricity costs and replacement costs for systems using fluorescent lighting.

Elimination of methane from the outer bulb of low‐pressure sodium lamps

The presence of methane in the outer bulb of low‐pressure sodium lamps causes undesirable heat losses by conduction through the gas. Methane is formed by the reaction of water vapor or hydrogen gas with traces of carbon in the barium flash getter present in the outer bulb. Elimination of methane has proved to be possible by using a chemical cracking device consisting of, e.g., a supported platinum catalyst. Methane conversion occurs permanently throughout the complete lamp life. After 10 000 h in service the gas pressure is below 10−5 mbar and is only made up of argon and helium.

Efficient 7-J flashlamp-pumped dye laser at 500-nm wavelength

An existing transverse flow flashlamp-pumped dye laser capable of operation at 500 pps for extended periods of time has been modified and optimized for operation at 502 nm using coumarin 504. Energies of over 7 J/pulse and efficiencies of over 1% have been demonstrated in single-shot operation. This has been achieved by using a spectral transfer dye in the flashlamp coolant to increase the useful output of the flashlamps. Flashlamps were tested at up to 400-J input per lamp for extended periods to develop lamp life data.

Light-Bulb Saver Performance

Information is provided on the characteristics of the incandescent lamp connected in series with a diode. The reduction in lm/W, a drastic decrease in color temperature, and the injection of dc in the power network disadvantages that outweight the only true benefit derived from this connection: a much longer lamp life. Theoretical calculations supported by experimental measurements prove that to keep the illumination constant the lamp wattage must be more than doubled. A simple economical analysis indicates that the cost of typical incandescent lamps, lasting 750 h or more, is exceeded by the cost of additional losses. The most serious drawback of this method is the injection of dc and current harmonics into the ac supply network.

Burn-In of Incandescent Sign Lamps

This paper describes an experiment in which it was determined that properly designed burn-in can not only eliminate a weak subpopulation, but also stabilize the healthy one. Accelerated life tests have been carried out on 30W sign lamps to show that the time-to-failure pattern is bimodal. The accelerated life data have been used to design burn-in process parameters, and to determine the deterioration caused in the healthy subpopulation by the chosen burn-in. The results showed no decrease in mean life of the healthy lamps. Rather, increased stability (lower standard deviation in life) has been observed. The burn-in procedure with parameters 240V and duration in the range 15-20s was successfully applied to the 30W sign lamps in order to eliminate the weak subpopulation. Due to fast turnaround of the procedure it can be implemented at the end of the production line. The high temperature thermal treatment of filaments during burn-in seems to relax structural stresses caused by fabrication process. The fact that the power coefficient obtained here differs from the one quoted by GE Technical Information TP-110 as well as by IES Lighting Handbook (Reference Volume 1984) should alert users of accelerated reliability tests to be wary of uncritical application of experimental factors taken from the literature, including this paper.

Irradiance and plant temperature monitor/controller

An irradiance and plant temperature monitor/controller has been developed and is being tested for use in controlled environments and in commercial greenhouses. Photosynthetic photon flux density was monitored using a quantum sensor, while plant temperature was monitored with an infrared thermometer. A microprocessor integrated the signals from each sensor and permitted a choice of priority control of high-intensity discharge (HID) lamps or infrared (IR) heaters for control of plant temperature. It also permits dimming of HID lamps inversely proportional to natural irradiance. Effects of the monitor/controller changes on high-pressure sodium lamp output to input ratio, lamp life and dimming response time will be illustrated. The effects of irradiance variations on leaf heating and cooling are presented.

蛍光ランプへの水銀合金の応用

As a rule, fluorescent lamps are filled with mercury and argon. As regards mercury dosiny into the bulb, the method which drops a few drops of liquid mercury through the exhaust tube has been employed. Such conventional method in production is of advantage to exhaust the gaseous impurities from the bulb but causes various defects of quality and characteristic. To eliminate such disadvantages, a manufacturing method which uses a mercury dispenser such as a strip mounted around the etctrode and releases mercury within the tube by means os R. F heating after sealing is introduced. Advantages using mercury dispenser are as follows:(1) The quantity of mercury enclosed in the lamp is very precise.(2) The pressure fluctuation of argon fill can be reduced, therefore it is possible to reduce the fluctuation of lamp life and to increse its average life.(3) In addition, if the new production process is applied for conventional mercury dosing method it is possible to decrease the mercury contents of lamp.

On the economic life of GLS incandescent lamps

The paper deals with the determination of the theoretical optimum length of life of GLS incandescent lamps at a rated voltage. The mathematics include both lamps whose wattage is rated and those with a rated luminous flux. An exact mathematical derivation leads to values of life surpassing those derived hitherto. These results support the suggestion, expressed already earlier by another author, that the designed life of GLS incandescent lamps for domestic lighting should be increased—for economic reasons—by at least 50 per cent.

Extending the life of low-power high-pressure sodium lamps

As new low power ratings of high pressure sodium lamps were designed and developed it was found that lamp lives were unexpectedly short compared with higher power ratings. The principal feature of failed lamps was extensive blackening of the arc tube with emitter material from the electrodes. Improvements to electrode construction and emitter processing offered some improvements but lamp lives were still not satisfactory. A detailed study was made of the processes occurring in the region of the electrode when the lamps were started. This revealed that sodium amalgam in electrical contact with electrode assemblies was causing the lamps to act temporarily as rectifiers, for time periods of up to two minutes, after the lamps were switched on. A new type of end plug was designed to prevent electrical contact between the sodium amalgam and the electrode assembly. Optimised 70W high-pressure sodium lamps made with this new end plug have been found to live six times longer than lamps containing the usual end construction.

Fluorescent System Performance of F40T12 and Smaller Lamp Diameters

Recent domestic and international developments with smaller diameter fluorescent lamps have prompted a review of lamp and system performance as a function of tube diameter. Limiting constraints on system performance when lamps of various diameter are used with the standard rapid start ballast are discussed. Performance comparisons are also made when these various diameter lamps are mated with ballasts optimized specifically for both 60 HZ and high frequency operation. The role of lumen maintenance in affecting the mean footcandle level throughout the lamp life is a key issue in these discussions.

The convection phenomena in the high pressure sodium lamp

High pressure sodium lamp is known as a light source in which convection phenomena of the arc are so small. Recently, arc tubes with larger diameter and high pressure xenon filling have been used for the HPS lamps with high color rendition or high luminous efficacy. It was found that the convection phenomena were not negligible in such HPS arc tubes. This was confirmed by measuring the 475 nm sodium line intensity and knowing by the displacement of the arc axis. The results are:(1) The convection becomes larger with increase in arc tube diameter and filling xenon pressure.(2) The convection becomes smaller with increase in the power input.The temperature difference between the upper and lowerside of the arc tube wall in the horizontal operation reaches 40-50°C and this local heating of the arc tube will be a problem in the life of HPS lamps.

高圧ナトリウムランプにおける対流現象

High pressure sodium lamps have been known as convection phenomena of the arc are so small. Recently, the arc tubes with larger diameter and high pressure xenon filling have been used for the HPS lamps with high color rendition or high luminous efficacy. It was found the convection phenomena were not negligible in such HPS arc tubes. This phenomenon was confirmed by measuring the 475.1nm sodium line intensity and knowing the displacement of the arc axis. The results are:(1) the convection becomes larger with increasing arc tube diameter and filling xenon pressure, (2) the convection becomes smaller with increassing the power input. And the temperature difference of the upper and lower side of the arc tube wall inthe horizontal operation was estimated 40-50°C and this local heating of the arc tube will be a problem in the life of HPS lamps.