Solid state lighting (SSL) systems are set to begin competing with a number of mature lighting technologies in mainstream markets for narrow- and wide-area illumination. The paper provides a summary overview of the present state of the established illumination lighting sector in terms of its scale and global energy usage, and its core technologies and their major performance characteristics. The established technologies are themselves still evolving in response generally to growing, world-wide, legislative and environmental pressures, and also, no doubt, to the stimulus provided by the rapid advances in the performance of white-LED modules. Several promising new thermal and discharge lamp technologies are identified and discussed briefly.

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Spectra of LED devices show a noticeable temperature and current dependence. Often this behaviour can be neglected. However, some applications like spectrometry or narrow band imaging take advantage of the spectral characteristics of LEDs. In such cases knowledge about the spectral behaviour is relevant. This article describes a measurement setup for investigating the influence of temperature and current on the spectral radiation of LED. Results from measurements are presented. Appropriate mathematical functions for modelling LED spectra are discussed and their applicability is rated. A new formalism for modelling of LED spectra in consideration of current and temperature is derived. With this approach, the prediction accuracy of the spectral behaviour is increased significantly.

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We have developed a polarization-independent reflection-type silicon photodiode trap detector and characterized its performance by laser beam-based measurement. Three dimensional CAD-based modeling enables us to optimize its interior design, resulting in minimizing each distance between centers of adjacent photodiodes by rotating each photodiode by 45° along each normal axis. It is expected by a simple ray-tracing simulation and also confirmed experimentally that the trap detector incorporating a photodiode with a large active area exhibits the largest acceptance angle ever proposed as the polarization-independent trap detector for the convergent incident beam. This is suitable for the national standard detector to realize and disseminate the cryogenic radiometer-based spectral power responsivity with high accuracy. It is also applicable to various kinds of working or transfer standard detectors for collimated or non-collimated monochromatic radiation. In addition, a history of development of trap detectors at national laboratories is reviewed.

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In this study road lighting measurements were made to investigate the impacts of vehicle headlights on luminance contrasts of various targets located on the road. Altogether seven different studies were made to investigate the contribution of halogen and high-intensity discharge headlights to road lighting. The measurement results indicate that in general, the use of dipped vehicle headlights, in the presence of road lighting, does not improve the visibility of various targets located on the road. In fact, in most occasions when the targets were seen darker than the background, dipped headlights reduced target contrasts and in some cases they even made the target merge into the background. The impacts of vehicle headlights are highly dependent on the vehicle, headlights type, target reflection factor, position of the target, position of the vehicle and road lighting conditions. As assumed, the effects of HID headlights on targets luminance contrasts were more significant compared to the ones of halogen headlights.

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The author, et al. made quantitative analysis of the loss caused by glare in the luminance required for identification of faces by fixing eyes on the fact that the illuminance required for the identification of persons varies depending upon the value of threshold increment (TI) studied by Caminada and van Bommel. We could obtain the following results from the experiment we conducted for the above-mentioned quantitative analysis: (1) The luminance (illuminance) required for identification of faces is dependent upon the sum of “equivalent background luminance + equivalent veiling luminance due to glare light.” (2) Reduction of the glare (equivalent veiling luminance) caused by luminaire can minimize the luminance (illuminance) required for face identification.

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Ulva pertusa is widely used as human food and also to feed cultured fish. U. pertusa is expected to be used as a bio-filter for purification of breeding - circulation water in the terrestrial aquaculture of fish. Insufficient sunshine and lower temperature causes bad commercial production. In order to realize stable cultivation of U. pertusa throughout the year, experiments on the growth of a sea water algae with sterile, U. pertusa Kjellman, due to supplemental lighting were performed. An illuminance of 1×10⁴ lx in the treatment areas and 2×10⁴ lx in the control, when the illuminance was 8×10⁴ lx in the greenhouse. Artificial lighting was added during the daytime in treatments 1∼3. The mounting height of each luminaire was adjusted to have a PPFD of 140 μmol m^-2s^-1. Each lamp had the R/FR PF ratio of 3.8, 1.2, 0.8. Considering of relationship between the growth and cumulative PPFD including daylight and supplemental lighting, the growth of the experimental area were superior to the control area. U. pertusa can be grown with warm sea water using supplemental lighting. But under the growth environment with daylight and supplemental lighting together, it is difficult to recognize whether the R/FR PF ratio influences photomorphogenesis.

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