Partly smoothing circuit suitable for a constant current type push-pull inverter has been developed for input high power factor and for increasing overall efficiency. The relation between the PF voltage ratio (partly smoothing DC voltage/inverter input peak voltage) and the luminous efficacy of fluorescent lamp was examined. The optimum PF voltage ratio is 50-60% to satisfy input high power factor and high luminous efficacy. The electronic ballast reduces power in 2×40 type (36 W) fluorescent luminaire by 28%, comparing with conventional core-coil ballast.
Recently the finite element method has been introduced for the analysis of non-linear magnetic field. A new method has been developed by us to analyze flux distributions in transformersrtaking into account the secondary load. In this paper, the formulation of the method is performed and the characteristics of a leakage transformer are analyzed using this method. The following items are cleared by the analysis: (1) Flux distribution with time. (2) Effect of load resistance on the flux distribution. (3) Relationship between the secondary voltage and current. (4) Primary and secondary current-waveforms. Computed results agree well with experimental ones. The newly developed method is applicable not only to the leakage transformer but also to transformers on load.
It was confirmed that the luminous flux of fluorescent lamps operated with high frequency (HF) current are determined by the wave forms of the lamp current. In this paper, current wave form of the dark angle part in case of 40 W linear shaped fluorescent lamp was investigated concerned with the luminous flux. In a HF operation, usually, the inverters are driven with the unsmoothed ripples from full wave rectifiers. In such cases, the envelope curve of the HF lamp current exhibits finite zero current phase region. The luminous efficacy would be reduced in considerable order because of the existence of dark angle part in HF lamp current. It was tried to make up continuous lamp current by additions of auxiliary sources in the lower region of rectifier voltage. It was proved experimentally that the luminous flux increased in every case of auxiliary power source. Further, the optimal form of the lamp current from the view point of the total efficiencies is investigated. The luminous flux can be calculated as a function of the wave form of the lamp current that might be regarded as an amplitude modulated HF.
This paper is concerned with multi-band detectors module, a kind of color measuring equipment, and its application to industrial automated visual inspection. For automated visual inspection which deals with color, high speed measurment of an object color with a high accuracy is important. Multi-band detectors module consists of mirror box and some detectors which have different spectral sensitivities, and is suitable for measurment of average color in relatively wide area of an object to be inspected. Using this module, efficiency of detecting signal light is more than one hundred times better that other method such as using dichroic-mirror. In this paper, firstly, efficiency of detecting signal light and uniformity of illuminance on detectors surface are theoretically analyzed. Secondly, designing method for multi-band detector is discussed. Finally, an application of the module to currency note sorter is described.
Luminous build-up characteristics of a compact fluorescent lamp with two separated inner tubes have been studied. In this structure, the temperature of the outer bulb, which determines mercury vapor density in the inner tubes, rises gradually after ignition. As a result, the time in which luminous flux reaches a sufficiently high value` is relatively long. It has been found that this luminous build-up is improved by setting silver ribbons near the electrodes. Mercury atoms adsorbed on silver ribbons evaporate since the silver ribbons are heated by radiation from filaments. This results in a rapid increase of the luminous flux after ignition. The surface area of silver necessary for improvement of the luminous build-up has been found to be about 0.5-1cm2 from the measurement of the amount of mercury adsorbed on silved ribbons.
Simultaneous juxtaposed brightness comparison has been used as a standard method for measuring brightness of colored lights. However, it is a more common task in our everyday lives to successively compare brightness of colored lights. In this report, we performed simultaneous and successive brightness matching between test lights and the: comparison white light to study differences yielded by these two comparison methods. In the simultaneous comparison condition, a test stimulus andt he comparison stimulus were presented at a same time for 1 sec, whereas in the successive comparison condition, a test stimulus was presented first, then the comparison stimulus appeared being preceded by 10 sec blank. The observer adjusted intensity of the comparison to make brightness match between the test and the comparison stimuli. White and 450, 490, 530, 570, 610, and 650 nm monochromatic lights were used-as test lights. The results show that test stimuli of longer wavelengths were estimated darker than other test stimuli, and that the standard deviation of brightness matching for successive comparison was greater than for simultaneous comparison. Some important implications about these results are discussed.
(Pb, Ca) ((Co1/2W1/2) Ti) O3 ceramic pyroelectric properties have been studied by changing the Ca concentration. With an increase in Ca concentration, the pyroelectric coefficient P and the figure of merit Fv increased and reached 4.43×10-8C cm-2°C-1, and 0.61×10-10C cm J-1, respectively. Pyroelectric properties have been improved to twice the values for the PbTiO3 ceramics. Ca introduction into PbTiO3 ceramics exerts a great influence on the pyroelectric properties. The infrared sensor using this ceramic has been fabricated by hybrid IC technique. The low temperature fired ceramic substrate was used by the advantage of its remarkably low thermal conductivity. The sensor can operate without the load resistance of the pyroelectric element. The maximum responsivity Rv value versus chopping frequency is obtained i a less than 1 Hz frequency range. Responsivity Rv and specific detectivity D* are 780 V/W and 1.1×108cm √Hz/W at 1 Hz, respectively. The sensor is applicable for human body sensing.
It is considered that the reflected light of the surface made from dielectrics is obtained by summation of specular reflected light component and diffuse reflected light component. This paper describes the optical reflected characteristics of surfaces (i, e., a method of separation of the two reflected light components) made from dielectrics, such as papers and fabrics which are widely used in illuminating engineering. The reflected light distribution curves are affected by roughness of the surfaces. In this paper, we proposed a method of separation of the two reflected light components using polarized light, in consideration of roughness of the surface and characteristic of specular reflected light.