A new neutral point type converter circuit with 200V and 100V input voltage tolerance is developed for application as electronic ballast. This circuit is a one-stage converter method electronic ballast, where circuit elements can be reduced by sharing the same switching elements by both converter and inverter circuit and still achieve high circuit efficiency. In this work, the circuit was built and experimented with a fluorescent lamp (NIPPO FLR36T6W) as output load. The proposed electronic ballast satisfies the IEC61000-3-2 class C harmonics standard and suitable for lighting a florescent lamp.

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This research paper aims to investigate dependence of fluorescence spectra of Susabi-nori (Porphyra yezoensis) on the excitation wavelength by comparing with absorption spectra of photosynthetic pigments. The intensities of the fluorescent peaks located at approximately 685 nm and 720 nm relatively increased by using the excitation light with the wavelength of approximately 430 nm, because the excitation light was mostly absorbed by chlorophyll-a. On the other hand, the intensity of the 580 nm peak relatively increased by using that of approximately 500 nm, because the excitation light was mostly absorbed by phycoerythrin. As a result, the intensity ratio of the 580 nm peak to the 685 nm peak was maximal at the excitation wavelength of approximately 500 nm. Therefore, it was concluded that the optimum excitation wavelength was approximately 500 nm for diagnosis of diseases and stresses of Susabi-nori.

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Radiation transport in high intensity discharge lamps (HID) can be calculated using ray tracing technique solving directly radiative transfer equation. The calculations reported in the present paper have been performed by applying basic equations of radiation theory in local thermodynamic equilibrium (LTE) plasma and assuming the cylindrical symmetry. Neither axial variations nor convention have been taken into account. Experimental values for pressure and temperature profiles are used to calculate the radiative and photometric characteristics of the lamp. Neutral Van der Waals and charged particles Stark broadening have been included in the line broadening.

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Questionnaire and field measurements were conducted to identify the light environment and the occupants' visual comfort in mid-scale office buildings in Japan. The answers of the questionnaire were obtained from 389 workers in 77 different buildings. The results have identified that more than 60% of the occupants attended to their work at their own desk in over 80% of working hours. Also, it was identified that only 10% of the occupants used task lighting. On the other hand, 90% of the occupants answered that they always turned on the ceiling luminaires. Field measurements were conducted in 9 different office buildings to identify the actual conditions of the environment around the windows. As results, it was identified that the percentage of the occupants who were dissatisfied with windows became higher in the cases where they could see nothing from the windows because they were covered by furniture, documents and so on placed around them than when they had an outside view through the windows. Over 30% of the area within the windows was hidden by furniture or documents in more than 30% of the measured buildings.

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Investigations in classrooms reveal that disturbing reflections on display screens are the primary complaint regarding the visual environment: in the classroom of the future such screens and hence complaints are expected to increase in quantity. An experiment was carried out to investigate the relationship between lighting, visual acceptability and luminous properties of display screens. This article presents preliminary results from tests using the adjustment method. The results suggest that the limits of luminaire luminance prescribed in current guidance, BS EN 12464-1:2002 and SLL Lighting Guide 7, are too low - modern display screens can tolerate higher luminances.

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The luminous intensity spatial distribution (LISD) of light emitting diodes (LED) can be categorized into two broad types, lambertian type LISD and batwing type LISD. Each type has its own specific characteristics and advantages. Compared to the lambertian type LISD luminaires, the luminaires or light sources with batwing type LISD have some advantages as they can illuminate uniformly a larger area on the target plane and distribute more flux inside the near luminaire area. By considering each single LED as a point batwing emitter, we analyze in this paper the first order design of a luminaire consisting of several LEDs assembled upon a planar surface to be applied in uniform illumination applications such as general lighting. By simulation and first order calculation, we analyze the impact on the illuminance uniformity by different batwing parameters (paramount angle, center versus paramount intensity ratio) and present the optimized batwing design parameters for uniform general lighting applications based on the LEDs luminaire mounting height and the LED-to-LED spacing in different luminaire packaging (string luminaire, ring luminaire, matrix luminaire, etc.).

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According to machinery statistics of the Ministry of Economy, Trade and Industry, the quantity of electric lamps produced in Japan was 613,000,000 (68.1% compared to the previous year). Of these, 73,000,000 were general lamps (88.1% compared to the previous year) and 32,000,000 were halogen lamps (79.3% compared to the previous year). The number of fluorescent lamps produced was 627,000,000 (72.9% compared to the previous year), and the number of general fluorescent lamps excluding backlights was 240,000,000 (86.0% compared to the previous year). Furthermore, the number of HID lamps produced was 7,600,000 (75.6% compared to the previous year). On the other hand, when looking at the sales amounts compared to the previous year, the results for general lighting electric lamps, halogen lamps, general fluorescent lamps, backlights, and HID lamps were 88.5%, 87.7%, 91.6%, 49.1%, and 76.4%, respectively. For compact fluorescent lamps, which are included within the numbers for general fluorescent lamps, sales amounts were 92.7% compared to the previous year, which was a large drop from 137.3% in 2008. The main causes mentioned for the decreases in production numbers and sales volume for these mainstream lamps are generally the economic recession and the rise of LEDs, a new light source that is now being used in the general lighting field. The main exhibition domestically was Lighting Fair 2009 held in March at Tokyo Big Sight. Internationally, it was Light Fair held in New York City in May. Although some new types of and research results for incandescent electric lamps are seen, their use and production continues to be stopped worldwide due to their low luminescence efficiency. In particular, the EUP directive (a directive related to energy using products and now named the ERP directive) was enacted in Europe in September. The sales of white diffused and clear types of incandescent electric lamps of 100 W or more and halogen lamps are prohibited. In Japan as well, major manufacturers continue to stop or reduce production of incandescent electric lamps. With fluorescent lamps, development into energy efficiency and longer life is healthy and new product releases of compact fluorescent lamps and ring fluorescent lamps are seen. Furthermore, the issue of reducing the amount of enclosed mercury remains and the IEC is continuing validity investigations of measurement methods. For light emitting diode (LED) light sources, 2009 was the year they saw full-fledged commercial viability and it may be remembered as the year that LEDs started to receive attention from average consumers. The luminescence efficiency of individual chips was reported to have reached 250 lm/W at the research level. In the Japanese production industry, the current market price of LED light bulbs quickly dropped to almost a third between the beginning and the end of the year. This drop is believed to be due to competition between the main existing light source manufacturers and manufacturers newly entering the market, the development and market introduction of LED products, and the flow of manufacturing processes to developing countries with cheap labor costs. In high-intensity discharge (HID) lamp field, product development and technological research related to ceramic metal halide lamps is as popular as ever. With increased emphasis on environmental conservation, mercury-free ceramic metal halide lamps are also being announced as reference exhibits at exhibitions. While reports regarding HID lamps cover fundamental research, reports of applications for growing plants are also being seen. There are also many reports about other types discharge lamps, including electrodeless lamps that use inductively-coupled mercury, microwave discharge lamps, and excimer discharge lamps. Furthermore, there are many reports about application examples of the nanotechnology as a new light source. With regard to lighting circuits, (…)

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According to statistical documents regarding building construction floor space from the Ministry of Land, Infrastructure, Transport and Tourism, the construction floor space of all buildings was 115,490,000 m², which was 26.6% less than the previous year and was the third year in a row for decline. Even for office space, there was a 20.0% decrease versus the previous year. In 2009, the rebuilding of historical buildings in major metropolitan areas continued, and efforts to reduce greenhouse gases also accelerated. The efficient use of office lighting was established through initial illuminance correction control using sensors, control for using daytime light, and control through motion sensors. Furthermore, in line with JIS standards revisions, lighting facilities that control discomfort glare have started to be implemented. Light emitting diode (LED) lighting is now being used in various types of facilities, including exhibition halls, multipurpose halls, conference rooms, and religious buildings. Even in art galleries, which demand high color rendering, LED lighting has started to be used for exhibits. In hospitals and retirement homes, there continues to be a strong consciousness of energy efficiency. The use of LEDs is increasing even for environmental lighting applications, and chandeliers and LED lightbulb downlights controlled by motion sensors have started to be employed. In 2009, the number of new theaters and halls constructed was very small. With a total number of six plus some small halls, it was the lowest number of new buildings in recent years. On the other hand, there is a feeling that all existing theaters and halls have gone ahead and performed renovations. Countrywide, forty-five facilities performed renovation work, which was a 50% increase over the previous year and was the highest number of renovations in recent years. In shops and business facilities, LED lighting has traditionally been often used as store fixture lighting and wall accent lighting. However, improvements in output and color rendering and the diversification of product types have progressed and full scale introduction into product presentation is now possible. In the accommodation, food and drink, and service industries, the use of LEDs as light sources is increasing in positions that require high color rendering, and renovations that emphasize energy efficiency are being introduced. Furthermore, LEDs are being employed for room lighting to provide modulated lighting that is suitable for when guests awaken. In the residential building industry, LED lighting fixtures are increasingly employed for high ceiling areas and underwater applications in order to utilize their greater control of the distribution of luminous intensity.

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