The CO₂ uptake rate (CUR) of the aerial part of cos lettuce (Lactuca sativa) was measured in pulsed and continuous light at an average photosynthetic (wavelength range: 400–700 nm) photon flux density (PPFD) of 100 μmol m^-2 s^-1 from white light-emitting diodes (LEDs). Three duty ratios of 25, 50, and 75%, combined variously with eight frequencies of 0.1, 0.2, 0.4, 0.8, 1.6, 3.2, 6.4, and 12.8 kHz were used for pulsed light irradiation. The CURs were significantly lower at a duty ratio of 50% for frequencies of 0.1–0.8 kHz and at a duty ratio of 25% for all frequencies than those in continuous light although the average PPFD was unchanged. These results indicate that pulsed light at lower duty ratios, combined with lower frequencies, makes CUR of cos lettuce lower than that attained in continuous light. We infer, based on a PPFD-CUR curve obtained with cos lettuce plant used in the experiment, that when greater PPFD is provided, pulsed light at lower duty ratios with lower frequencies is less advantageous than continuous light for photosynthesis.

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Not only illuminance but also color of light, color of interior surfaces and luminance distribution contribute to the visual environment which affects our mood as well as perception of brightness. In order to identify the effects of light color, surface color and luminance distribution on perceptions of brightness and atmosphere in living rooms, a subjective experiment using a scale model was carried out. The relationship between Bright–Dark sensation and NB value showed that average NB value in the space could not predict Bright–Dark sensation. A further study on the effects of the color of light and the color of the wall on Bright–Dark sensation is necessary. The CCT of the lamps had effects on “Natural–Unnatural”, “Relaxing–Tense”, “Comfortable–Uncomfortable” as well as “Warm–Cool”. The 5200 K lamp gave a more comfortable and relaxing effects to the subjects than the 2800 K lamp.

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A portable-sized full-color LED illumination panel and a Palm-sized Controller were developed. In addition to 3 primary color (red, green, and blue) LED, white LED was used in order to achieve high illuminance in the white illumination region and to facilitate realization of pastel colors. A mobile computer was used as the controller. Adjustment of illuminance is performed through the duty ratio control device connected to the computer. By using this controller system, 4 types of LED could be controlled according the input 3 information (Chromaticity Coordinates and light intensity) by a real-time calculation. Up to 255 illumination panels can be connected. This system allows individual control of a maximum of 255 illumination panels, or control of all illumination panels using the same illumination conditions. By using this system, 9 types of illumination colors were selected and some characteristics were measured. For every illumination, the chromaticity coordinates hardly changed above the duty ratio above 30%.

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According to machinery statistics of the Ministry of Economy, Trade and Industry, in 2011, the quantity of incandescent electric lamps produced in Japan was 725 million units (91.0% year-on-year). Of these, 47 million units were general lamps (66.7% year-on-year) and 28 million units were halogen lamps (79.5% year-on-year). The decrease in total production quantity of incandescent electric lamps is less than 10% only because of the large quantity of automotive lamps included in the statistics. The quantity of fluorescent lamps produced was 284 million units (52.1% year-on-year), and the quantity of general fluorescent lamps, excluding backlights, was 211 million units (84.1% year-on-year). Additionally, the quantity of HID lamps produced was 8.9 million units (91.2% year-on-year). On the other hand, year-on-year sales volumes were 71.2% for general lighting electric lamps, 69.0% for halogen lamps, 85.4% for general fluorescent lamps, 25.1% for backlights, and 91.6% for HID lamps. The compact self-ballasted fluorescent lamp, which had not been separately listed until 2010, had been included in the “other fluorescent lamps” category and specific figures, although not available, are undoubtedly decreasing. According to a report by a private research company, since the Great East Japan Earthquake, sales of bulb-type LED lamps as a percentage of total sales have been increasing rapidly, but compact self-ballasted fluorescent lamps, although higher-efficiency than incandescent electric lamps, have continued to decrease slowly as a percentage of number of sales per month, and consumer awareness of energy savings seems to be directed toward LEDs. To summarize these figures, from a long-term perspective, the replacement of lamps with LED light sources has been steadily progressing, with the fastest rate of progress being exhibited for backlights and relatively slow progress for automotive lamps, which are inexpensive and used in large quantities, and for high-intensity HID lamps. Major exhibitions in 2011 were Lighting Fair 2011, which was held in March in Japan, and Lightfair International 2011, which was held in May in Philadelphia, PA in the USA. Announcements of new products or new research activities concerning incandescent electric lamps were almost non-existent. In the future, as LEDs are used more and more, incandescent electric lamps may only remain significant as a comparative example when discussing color rendering properties and the like. In recent years, although the development of fluorescent lamps has been advanced for energy savings and longer service life, outstanding new products are no longer being seen. R&D activities are also gradually decreasing despite the many remaining challenges, such as hot cathode behavior and the discharge state of an electrodeless lamp. New product development and research of LED light sources has been very active. As for bulb-type LED lamps, many new products have introduced, and in particular, lamps for which the distribution of luminous intensity toward the base direction has been made wider, which had been a challenge until last year, have been developed one-after-another, and lamps that realize a luminous intensity distribution angle of approximately 300°, which is equivalent to that of an incandescent electric lamp, have also appeared. In Japan, a cabinet order amending a portion of the Order For Enforcement of the Electrical Appliance and Material Safety Law has been promulgated, mandating that the PSE mark be affixed to bulb-type LED lamps (effective as of 7/1/2012). For HID lamps, (…)

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