Discharge properties of CVD polycrystalline diamond and MgO single crystal (111) plates as electrodes in a cold cathode fluorescent lamp for liquid crystal display backlighting system were investigated. CVD polycrystalline diamond and MgO single crystal (111) plates with polished surface and no polished surfaces, each were employed as the test electrodes. The breakdown voltages for electrode materials of both electrode materials under various Ne pressure filling conditions were measured with a V-Q Lissajous method. The breakdown voltages in them with no polished surfaces were obtained lower than those with polished surface. The relationship between the secondary electron emission coefficient and the surface roughness of CVD polycrystalline plates were influenced strongly as compared with that of MgO single crystal (111) plates.

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It is expected that in the future white LEDs will be widely used in practical applications including replacing conventional lighting in offices and homes. The white LED light source of matrix arrangement is also considered in it. On the other hand, although now the unified glare rating (UGR) is widely used for evaluation of the discomfort glare of the interior lighting, UGR is a thing for a uniform light source, and its application to the matrix light sources that have non-uniform luminance has not been considered. The aim of this study is to clarify the position index which is one of element of UGR for the matrix light source. In this case, to apply the position index for a matrix light source to UGR, the concept of the revised position index is invented. As the preliminary experiment, method for measuring the position index was conducted, and as the experiment, position index for the matrix light source was conducted and compared with the uniform light source. The results of the experiments show that the position index is decided by the relative angle between line of sight and light source. It is also found that the matrix light source have larger position index than uniform light source. Furthermore, it is shown that the discomfort glare caused by a matrix light source can be evaluated by applying the revised position index to the UGR.

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The relationship between the eye movement pattern during stair descent and illumination was studied in 4 elderly people in comparison with that in 5 young people. The illumination condition was light (85.0±30.9 lx) or dark (0.7±0.3 lx), and data of eye movements were obtained using an eye mark recorder. A flight of 15 steps was used for the experiment, and data on 3 steps in the middle, on which the descent movements were stabilized, were analyzed. The elderly subjects pointed their eyes mostly directly in front in the facial direction regardless of the illumination condition, but the young subjects tended to look down under the light condition. The young subjects are considered to have confirmed the safety of the front by peripheral vision, checked the stepping surface by central vision, and still maintained the upright position without leaning forward during stair descent. The elderly subjects, in contrast, always looked at the visual target by central vision even under the light condition and leaned forward. The range of eye movements was larger vertically than horizontally in both groups, and a characteristic eye movement pattern of repeating a vertical shuttle movement synchronous with descent of each step was observed. Under the dark condition, the young subjects widened the range of vertical eye movements and reduced duration of fixation. The elderly subjects showed no change in the range of eye movements but increased duration of fixation during stair descent. These differences in the eye movements are considered to be compensatory reactions to narrowing of the vertical visual field, reduced dark adaptation, and reduced dynamic visual acuity due to aging. These characteristics of eye movements of the elderly lead to an anteriorly leaned posture and lack of attention to the front during stair descent.

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Following article deals with the impacts, evaluation and elimination methods of nocturnal light on health. Evaluation of obtrusive light inside the interior is linked with current legislation on evaluation in exterior conditions. Night illumination factor is additionally proposed. Evaluation of obtrusive light inside the interior is reasonable for certification of building interior environment.

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We have developed phosphor-conversion green light-emitting diode (LED) based on a combination of near-ultraviolet (n-UV) LED and the green phosphor material of SrBaEuSiO, which can provide a luminous efficacy over 110 lm/W at a wavelength of about 530 nm. The present green LED structure is expected to cover the longer wavelengths beside 520 nm that are impossible to generate by semiconductor LEDs with high luminous efficacy. By improving the external quantum efficiency of n-UV LED chips and the extraction efficacy in the phosphor, it is theoretically anticipated that the luminous efficacy can be increased to be about 210 lm/W.

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We have demonstrated a special plan exhibition for appreciation of Japanese antique ink painting of “The trip to Sesshu”, which used the novel warm white light-emitting diode (LED) lighting system having the average color rendering index (Ra) = 96 and special color rendering indices R₉ (95) and R₁₅ (98). A viewer is seen with an original hue and can feel a delicate three-dimensional impression. Comparing with a conventional triple A fluorescent lamp system, the developed white LED system can provide the superior illuminance properties and extremely low electric power consumption.

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At some point in our lives most of us will be affected by reduced visibility from fog. Fog is defined as the visible portion of small water droplets suspended in the atmosphere on or near the earth’s surface. Visibility can be measured by several methods although all are partially limited to some degree. The most common and readily available methods are by : trained human visual observers, transmissometers and forward scatter / back scatter meters. The method used to determine night time visibility is based on the contrast between a bright point light source against a dark or black background. Contrast reduction law does not hold in fog because the target apparent luminance depends on the droplet size. By measuring human spectral sensitivity with LED light brightness inside of fog, it is understood that short wavelengths are scattered much more strongly than long wavelengths. However, in human vision RB and RY color that can be easily seen in foggy conditions, despite the fact that the color wavelength is not as long as red color.

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In this research, we measured the wavelength difference limit for binocular colour vision about peripheral visual field, by using a three-dimensional display to present dichoptic stimuli to the left and right eye respectively. The wavelength range of the stimuli was selected from 450 nm to 650 nm. The size of stimulus was 2° arc of visual angle, and the brightness was set 15 cd/m². The results show that colour fusion occurs more difficult with central visual field than peripheral visual field. More importantly, it offers the basis of important fundamental data for some important optical instruments, for example the designs of optical microscopes.

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According to the machinery statistics by Ministry of Economy, Trade and Industry (METI), the total of domestic light bulb production in 2006 was 1,101 million (88.5% year-on-year). Production for general purpose illumination light bulbs and halogen light bulbs accounted for 122 million (99.2% y/y) and 45 million (96.3% y/y), respectively. The total of fluorescent lamp production was 988 million (114.9%) and the production of general purpose fluorescent lamps excluding backlights accounted for 367 million (101.7% y/y). Further, HID lamp production was 10 million (106.3% y/y). What is noteworthy regarding such lamp production is that, similar to the previous year, the sales volume (amount) of lamps for general illumination exceeded 100% against the previous year, indicating a steady shift to high value added products. Major lighting exhibitions in 2006 included the Light + Building Trade Fair held in Frankfurt in April and the Light Fair International 2006 held in Las Vegas, U.S.A. in May, both of which demonstrated signs of acceleration toward energy saving, high efficiency and resource saving. As for incandescent lamps, products filled with larger atomic weight gases aiming at higher efficiency/longer life are becoming the mainstream. As for new technologies, it was experimentally demonstrated that infrared radiation can be suppressed by processing micro cavities to metal plates made of tungsten, tantalum, etc. For fluorescent lamps, straight and circular fluorescent lamps achieving a longer life/higher luminous flux maintenance factor continued to be widely developed/launched again this year. For compact fluorescent lamps, energy saving/high efficiency products, multifunctional type products combined with LED and new shaped products were launched. As to HID lamps, ceramic metal halide lamps with high efficiency, improved color rendering, longer life and higher luminous flux maintenance factor were commercialized one after another. Numerous studies and analyses, on discharge models were reported. Further, studies on ultra high-pressure mercury lamps as light sources for projectors are becoming the mainstream of HID lamp related researches. For high-pressure sodium lamps, many studies on plant growing and pest control utilizing low insect attracting aspects were also reported in 2006. Additionally, for discharge lamps, the minimum sustaining electric power for arc tubes employed in electrode-less compact fluorescent lamps was investigated. For Hg-free rare-gas fluorescent lamps, a luminance of 10,000cd/m² was attained by a 1 meter-long external duplex spiral electrode prototype using Xe/Ne barrier discharge. As to startup circuits, the commercialization of energy saving and high value added products mainly associated with fluorescent lamps and HID lamps are becoming common. Further, the miniaturization of startup circuits for self electronic-ballasted lamps has advanced. Speaking of the overall light sources and startup circuits in 2006 and with the enforcement of RoHS in Europe in July, the momentum toward hazardous substance-free and energy saving initiatives has been enhanced from the perspective of protecting the global environment. It is anticipated that similar restrictions will be globally enforced in the future.

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According to the statistics by the Ministry of Land, Infrastructure and Transport, the total floor space of all building construction started was 188.87 million m² (1.5% increase y/y), marking the fourth straight year of increase. Many large-scale buildings under construction in central Tokyo become fully occupied by tenants before completion. As for office buildings, it is required to develop comfortable and functional office spaces as working styles are becoming more and more diversified, and lighting is also an element of such functionalities. The total floor space of construction started for exhibition pavilions, multipurpose halls, conference halls and religious architectures decreased 11.1% against the previous year. This marked a decline for 10 consecutive years and the downward trend continues. In exhibition pavilions, the light radiation is measured and adjusted throughout the year so as not to damage the artworks by lighting. Hospitals, while providing higher quality medical services and enhancing the dwelling environment of patients, are expected to meet various restrictions and requirements, including the respect for privacy. Meanwhile, lighting designs for school classrooms tend to be homogeneous, yet new ideas are being promoted to strike a balance between the economical and functional aspects. The severe economic environment continues to be hampering the growth of theaters and halls in both the private and public sectors. Contrary to the downsizing trend of such facilities, additional installations of lighting equipment were conspicuous, and the adoption of high efficacy lighting appliances and intelligent function control circuits are becoming popular. In the category of stores/commercial facilities, the construction of complex facilities is a continuing trend. Indirect lighting, high luminance discharge lamps with excellent color rendition and LEDs are being effectively used in these facilities, together with the introduction of lighting designs that take into account the traffic flow of shoppers. For hotels, restaurants and other service industries, lighting equipment that corresponds to the purpose of the facility is being employed. An innovative lighting design was observed for the bath space, while such idea was not so much emphasized in the past. As to residences, illumination positioning plans that cope with diversifying lifestyles in an innovative space expanding in a horizontal or vertical direction using high efficient light sources/appliances are being introduced.

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