In order to know the effect of the arc power on the radiation power, a trial simulation of the radiation power emitted from high current wall-stabilized arcs has been carried out by using the relation E∝Im, where E is voltage gradient and I is arc current. Radiation powerΦ can be estimated to be proportional to In, where n=2(1-m), and also to PD, where P is input electric power and D=2(1-m)/(1+m):Φ∝I2∝P2 in the mlddle current range from 10 to 100 A because of m=0, and Φ∝I1.2∝P0.86 in the high current range over 1, 000 A because of m=4/10. Similar relations hold in other different gases such as Ar, N2, SF6 etc. at 0.1MPa. The estimated values of n and D almost agree with the experimental ones. Finally, it was clarified that these exponents n and D are closely related to the high temperature transport properties of gases.

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Discharge lamp's electric characteristics, which are nonlinear and hysteretic, can be computed by using the equivalent conductance model. It is important to theoretically represent the lamp voltage and current waveforms under the various conditions. But electric characteristics under the saturated condition can't be computed correctly, because the lamp model equation which has been used is based on the un-saturated condition in which mercury inside the lamp has evaporated completely.
We paid attention to the fact that a lamp voltage shows the condition of the inside of the lamp under the saturated condition. In this paper, we use the ratio of the lamp voltage as parameter which shows the condition of the inside of the lamp. Then we expanded the lamp model equation using the ratio of the lamp voltage. Now, by using this new lamp model equation, electric characteristics of the saturated discharge lamp can be computed.

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In general, HID lamps may be easily extinguished by momentary outage or voltage drop of power source, and they take a few minutes to be restarted. We tested the metal halide lamps, high-pressure Hg lamps and high-pressure Na lamps. On this paper, we describe their extinguishing characteristics by momentary drop of source voltage, discharge voltage after they have been extinguished, and trial on the instant reignition of hot HID lamps.
High-pressure Na lamps were more easily extinguished by half cycle of 60Hz voltage drop, but by one or more cycle drop, they were less easily extinguished than the other kind of lamps. Restriking & keeping voltage of these Na lamps are lowest, and these voltage of metal halide lamps are highest. It is able to restart hot HID lamps within 1 minute by superposing high voltage pulse on power source peak position, and also able to restart hot high-pressure Na lamps instantly.

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We developed a simple numerical arc model for calculating temperature distribution in a spherical microwave discharge lamp which is filled with mercury and iodine. The model is consisted of an energy balance equation, with the assumption of local thermal equilibrium. It is also assumed that the arc has spherical symmetry, which results in disregard of convection and approximation in absorption of microwave. As the radiation loss, we consider HgI molecular radiation and simplified self-absorption of Hg resonance lines, in addition to radiation of some Hg non-resonance lines. The calculated results indicate that as follows: The temperature profile is almost constant from the center of the lamp near to the wall, and sharply decreases there. When mercury content increases, temperature near the wall decreases, and the distance between the plasma and the wall increases. All these agree reasonably with those of measured. On the other hand, there are some differences in detail between measured and calculated results. It seems that these differences result from disregard of convection in the model. It is concluded that this model can be used for predicting the temperature characteristics of the lamps qualitatively.

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In order to utilize the red negative glow of Multi-Color Hg-Ne discharge lamp, we put a pair of aluminum foils or transparent and electrically conductive Indium-Tin-Oxide (ITO) thin films on the outside of the lamp. When it's turned on by several tens kHz sinusoidal wave power source with these outer electrodes, the red negative glow appears on the inner wall of the lamp. We can control the emitted color of the lamp well from red to blue with 100-200cd/m2 of luminance, by superposing negative glow discharge along radial direction on positive column discharge along axial direction.
We applied these ITO transparent outer electrodes to straight FL15EX-N fluorescent lamp, and were able to get 500-600cd/m2 of luminance by only negative glow discharge. We can get 6000-8000cd/m2 of luminance by superposing 10W input of positive column discharge along axial direction with inner filament electrodes on negative glow discharge with outer electrodes, and 3500-6500cd/m2 by superposing 6W input. We can control the color temperature of this fluorescentlamp within a range of 300K maximum by this method.

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The luminous color of a fluorescent lamp is determined by the mixture ratio of the phosphors, but it can not be changed when all phosphors are excited only by the mercury resonance lines. The fluorescent lamp which is coated with the mixed phosphors with different excitation spectra, and which is filled with the mixed gases emitting the excitation radiation of each phosphor, can change its luminous color by means of varying the intensity ratio of the excitation spectra. The mercury-xenon mixtures emit the intense mercury resonance lines in the high frequency pulsed discharge and the strong xenon resonance line in the low frequency one. The phosphor NP-320 (3.5MgO•0.5MgF₂•GeO₂: Mn) is mainly excited by the mercury resonance line 253.7 nm. On the other hand, NP-1047 (Y2SiO₅: Ce) is considerably excited by the xenon resonance line 147 nm. When a lamp is coated with the phosphor NP-626 mixed with NP-320 and NP-1047 and filled with mercury- xenon mixtures, its luminous color can be changed from (x, y)=(0.224, 0.158) to (x, y)=(0.410, 0.2224) by CIE chromaticity coordinates. If the lamps are coated with the mixed phosphors emitting different color luminescences, their colors can be controlled in the different ranges. The luminous color of a lamp coated with the phosphor mixed with NP-60, NP-70 and NP-1047 changes from (x, y)=(0.287, 0.259) to (x, y)=(0.396, 0.354). Its change of color corresponds to the range from the daylight-type to the lamp-type of the fluorescent lamp.
The most important problem to be solved for general use of this variable color fluorescent lamp is that the luminance in the pulsed discharge of the mercury-xenon mixtures must be increased.

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A few spectroscopic methods were applied for inductively-coupled metal-halide-lamp in order to measure density distributions of electron, ion and excited species and to determine temperature distributions. (1) Stark-broadened and -shifted spectral profiles of Na emission lines (568.266, 568.822nm) were used to determine electron density distributions, whose maxima were increased from 3 to 5×1021m-3 with increase of RF power from 150 to 300W. (2) Laser induced fluorescence (LIF) method was applied for the ground state of scandium ion, and obtained signals showed the decrease of up to 40% of their intensities with increase of RF power. (3) Optical emission spectroscopy was used to determine the density distributions of excited species [Sc*, (Sc+)*, Na*]. Emission intensities of spectral lines of (Sc+)* were all decreased up to 40% with increase of RF power, although those of Sc* and Na* were all increased up to three times and even thirteen times, respectively, on the same conditions. (4) From the ratios of emission intensities of spectral lines of Sc* and (Sc+)*, the temperatures were estimated to be about 5, 000K at maximum, which were decreased by about 300K with increase of RF power.
A discharge model based on the thermal equilibrium analysis, was introduced to explain all the above experimental results, which suggests i) the increase of incoming flux of metal atoms, especially of Na atom, from the quartz wall and ii) the resultant decrease of the arc temperature, with increase of RF power.

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Recently, high frequency inverters are widely used in the electronic ballasts for fluorescent lamps. A new combined voltage-resonant inverter is presented to suppress the input current harmonic distortion in the electronic ballasts. In this inverter, the voltage-resonant active filter and inverter are combined, and a switch of the active filter is used in common as that of the inverter. The purpose of this paper is to describe the operation of the combined voltage-resonant inverter with an added simple control circuit and to examine its fundamental performance characteristics. As a result, the high power factor, low input current harmonic distortion factor, low crest factor of the output voltage, low voltage stresses on the main switch and the smoothing capacitor can be realized by using the new control strategy in cases of ±10% change of the input voltage or ±20% change of the load resistance as a fluorescet lamp.

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An arc generation of a long-pulse spiker-sustainer excimer laser with about 250ns of pulse width, is discussed by using time-varying spectroscopic method. First arcing occurs during a main discharge for laser excitation and shows XeII spectrum, while a glow-like discharge represents only XeI spectrum, the metallic spectrum such as NiI caused by vaporization of electrode material begins to appear just after the termination of the main discharge. Second arcing occurs after about 2μs, which brings strong intensity of NiI spectrum. It means that the reignition arc might be produced in a metallic vapor that appears during the main discharge. Accordingly, it is concluded that the reignition arc is inherently metallic, which is different from the main arc with rare gas plasma.

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Optical properties have been investigated in azobenzenc (Az) LB ultrathin films adsorbing cyanine dyes on silver thin films using attenuated total reflection (ATR) measurements. Az LB ultrathin films were deposited by the diffusion adsorption method. The Az LB films containing the dyes showed strong optical absorption bands in the visible light region and the absorption bands remarkably changed as the LB films were annealed. The ATR properties of the LB films after the heat treatments strongly depended upon the wavelengths of the lasers, and the real parts of the complex dielectric constants decreased as the wavelengths became shorter. The dispersion properties of the Kramers-Kronig relation calculated from the absorption spectra coincided with the experimental results. The properties are thought to be due to an anomalous dispersion caused by the strong absorption. The results are useful for optical applications of LB films with strong absorption bands.

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In our investigations, the generated voltage was ascertained in MIM elements of Langmuir-Blodegett (LB) film which is dielectric ultrathin film, and it was considered that the cause of the voltage generation was due to diffusion of electron in LB film. Change of the generated voltage was observed in early stage, and following characteristics were ascertained.
(1) The generated voltage reached the maximum value then decreases and became constant.
(2) The maximum generated voltage was increased with increase of the resistance connected between both electrodes (less than l mV in the case of R=108Ω, about 10mV in the case of R=1010Ω).
(3) The lapse of time until to reach the maximum generated voltage was increased with increase of the resistance connected between both electrodes (10s in the case of R=108Ω, 300s in the case of R=1010Ω).
In the present paper, the generated voltage in early stage is alalyzed by the electron diffusion and compared with the experimental values.

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