Recently, low wattage HID lamps are developed and used steadily for an indoor illumination such as offlces or stores. The ballast for the lamps is required to be in smaller size and lighter weight, and moreover it is required to have excellent function with good controllability. If the Simulation model of the HID lamps is given for the behavior in transient such as in starting period, it is very useful for analysis and design of the ballast. In the paper, a simulation model for hige pressure mercury lamps is proposed by means of state variable method. The equations are taken account of the state of each portion such as pressure, temperature and mercury vapor density, etc. The coefficient values of the equations are investigated physically and determined referred to experiment. The calculated results are in good agreement with the experimental results. Then, it is verified that the simulation model is available for the high pressure mercury lamps.
The clear sky light is generated through the process that the direct sunlight is successively scattered by the air and aerosol in the turbid atmosphere and repeatedly reflected by the earth's surface. The scattering-transmitting functions of the direct sunlight and the reflected light from the earth's surface were set up theoretically and the spectral power distributions of the clear sky light were estimeted. It became clear how following factors effect the change of the clear sky light respectively. (1) The scattering light by the air and that by the aerosol. (2) The first scattering light and the higher order scattering light than the first. (3) The reflected light from the earth's surface.
There is much interest in operating HID lamps at frequencies in the several tens k Hz range, since the reduction can be expected in the weight, the size, and the power dissipation of the ballast, and also some of features will be added. The problems made by the acoustic resonances are the change of colour, the unstable arcs, which causes fluctuations in the intensity and distribution of emitted light, the extinguished arc caused by rising the voltage, and/or, the tube cracking. There have been many studies in this field, but only a few studies which reduced the acoustic reasonances have been done. Therefore, the high frequency operation with a full-electronic ballast has never been applied for HID lamps on the market. The purpose of this work is to find the method of reducing the acoustic resonances. And, from view points of the shape of arc tube, we have analysed the pressure distribution by method of using the finite element method, and made several experiments of the arc behavior by changing the tube shaphs. As the result of the study, we found that the specific shape of end portion of the arc tube is very effective to reduce the acoustic resonancesunder the condition of the high frequency operation with the frequency modulated wave. This method is useful to operate higher wattage HID lamps than 250 W.
The present study confirms that the individual variations of the Stiles' 20 color-matching functions are physiologically well predicted by those of eye-lens and macular optical densities. The principal-component analysis of the blue colormatching functions shows the significance of the two independent spectral components, which are expected to correspond to lens and macular optical densities. The lens and macular densities for each of the Stiles' 20 observers are estimated by using their published data physiologically measured. The estimated densities well predict each of the Stiles' 20 colormatching functions. The singular-value decomposition of the estimated 20 color-matching functions gives a good estimate to the standard-deviate observer derived from the original Stiles 20 color-matching functions by using the same procedure.
Becently, interior lighting system designs trend to increase their complexity according to the choices of various lighting systems, sources and luminaires under westernising our life styles. Conventional methods based on the integral equation or simultaneous equations have been widely used to predict the illuminance distribution in interior lighting, where assuming convex enclosures, diffuse reflection and symmetrical luminous intensity distributon, etc, however. In the case of practical interiors all of them can not necessarily be satisfied. It is pointed out that interior illuminance calculation by the Monte Carlo simulation (MCS) in the complicated lighting Systems, including concave surfaces with both diffuse and specular reflectnace component, will be inevitable in the near future. Though MCS procedure solving the problems abovementioned has already beendeveloped by Tregenza to some extent, relatively little study based on the practical numerical experiments has been given to the illuminance estimations in interiors. This paper deals with the application of MCS to solving the interreflected component problem in the interior lighting design and the results obtained from both numerical experiments and calculations. As a result. it becomes clearly that the lighting calculations by using MCS appear to have the advantage of other methods in the simulation of the interior having complex geometry and irregularly diffusing surfaces.
This paper describes the results of high frequency operetion and control of a 90 W low pressure sodium lamp by means of an electronic ballast. The low pressure sodium lamp is operated at about 125 k Hz by means of at electronic ballast of self-commutated constant current push-pull inverter with power MOSFET from fiat DC voltage source. The circuit efficiency and luminous sefficacy are both im proved, and then, the total luminous efficacy increases about 1.3-1.5 times compared with the operation of conventional ballast for commercial 60 Hz frequency. The effects of ripple, containing in a DC source of the rectified commercial AC voltage, on input power factor and total luminous efficacy are investigated by experiment. Based on the results, a controllable operation circuit considering both input power factor and luminous efficacy is proposed by authors. The experimental results by the circuit show good regulation for the constant voltage control to variation of supply voltage. The stable dimming is possible to 70% of rating light output without muct reduction of total luminous efficacy and input power factor.