Current attitudes to daylighting and electric lighting design need reviewing, revitalizing and redirection. Daylighting design methods involving static concepts such as daylight factor and average or mean skies are criticised. Similarly, consideration of electric lighting design as the means of providing uniform horizontal illuminances and glare checks in satisfaction of code requirements are also criticised as limited. Consider the light sources. Fixed spectrum and fixed light output from electric light luminaires on the one hand, and variable spectrum, variable direction and variable, fluctuating, output from sun and sky on the other hand. This is the contrast to be recognised and incorporated in integration of the two light sources. This is one challenge in lighting design in satisfaction of human needs. Many existing computer programs for lighting calculations do not recognise these realities. Static concepts for daylight are not lighting design, and integration of such programs into energy conservation calculations are quite misleading. New computer programs incorporating variability of daylight as it occurs naturally present a further challenge. The Commission internationale de L’Eclairage (C.I.E) International Daylight Measurement Programme (IDMP) aims to provide the necessary daylighting design data for a new approach to lighting design and energy conservation in lighting. Of course, new computer programs will be developed from this data. For this daylight measurements programme special equipment specifications have been defined and participants must comply with strict standards of data acquisition and reporting. In electric lighting design, new work is required to develop design methods for variability in spatial illuminance, and also to build on earlier work involving vector and scalar illuminances in modelling, and applications of semicylindrical and cylindrical illuminance in a 4-dimensional approach to lighting, where the fourth dimension can be considered to be time, or change, or variety/variability in satisfaction of human needs. With changed attitudes in lighting engineers the problems of daylight and electric light, new windows and people, will provide an exciting challenge for the future.

View full abstract

The electron swarm parameters in Hg/Ar and Hg/Ar/0.1%H₂ mixtures are analyzed using a Boltzmann equation in which the generation of secondary electrons through Penning and cumulative ionization, and collisions between two metastable Hg (Hg^*) atoms are taken properly into consideration. The present values of the Townsend first ionization coefficient and the concentration of Hg^* agree well with the experimental values of Burgumann et al. and Bigio respectively. It is shown that mixing 0.1%H₂ in Hg/Ar lowers the ionization coefficient significantly. This lowering effect is discussed how it influences the characteristics of discharge lamps.

View full abstract

We have developed the computer simulation program in the design of optical multi-layers including a heat absorbing layer which are coated on the metal (Aluminum) based substrate. We have investigated the influences on the spectral reflectance on the case of changing the thickness of each layer, refractive indices and the degree of oblique incidence of light. As the result of the aforesaid, optical multi-layers including the heat absorbing layer were deposited on the substrate by the ionplating method. Then, we have manufactured mirrors which absorbs infrared radiation of about 80 percent from a lamp. Simultaneously, we have evaluated several characteristics of the optical multi-layers and confirmed that they are fit for practical use satisfactory.

View full abstract

In terms of designing daylighting of good quality, it is very important and necessary to predict and evaluate in advance the luminous environment in an interior space. Therefore, not only illuminance but also luminance distributions by daylight in an interior space should be predicted as precisely as possible. A new method of daylight calculation was developed. This method predicts luminous environment in an interior space of arbitrary shape lit by sunlight and skylight through the translucent or transparent openings. A new daylight source model under all-weather conditions is developed for the direct illuminance calculation. The luminous flux transfer method is adopted for the indirect or total illuminance calculation. In the luminance calculation, the sky luminance distribution seen through the transparent openings is predicted as well as the interior luminance distribution. The method was applied to a computer program of daylight and artificial light calculation on a membrane structure with open and closed translucent roofs under any condition of weather, location, date and hour. The program predicts the illuminance distribution in the interior space and the luminance distribution on the visual field watched at any view point. The luminance contrast of the fly ball is also predicted in the case of a baseball stadium.

View full abstract

The absolute spectral responsivity of inversion layer silicon photodiodes has been self-calibrated on four wavelengths using lasers, and interpolated over the entire visible region. Using the calibrated photodiodes in combination with a V (λ) filter and a precision aperture, a photometric standard detector has been constructed. The spectral transmittance of the filter was measured by a method which can eliminate, in principle, the errors caused by the interreflections between the filter surface and the photodiode surface. The calibrated detector was compared with an illuminance standard lamp calibrated at ETL (Electrotechnical Laboratory) in Japan, and also with luminous intensity standard lamps maintained at NIST of the U.S. The luminous intensity measured by the detector agreed with the values of ETL and NIST within a 0.5% difference.

View full abstract