TOP / Publications / Journal of Light & Visual Environment (JLVE) / Volume 30 Number 2, August, 2006
State of Art in the Science and Technology of Electrical Discharge Light Sources
G. ZISSIS and J. B. ROUFFET
51
A New-type of Xenon-Neon Barrier Discharge Fluorescent Lamps: Double Helical External Electrodes Lamp (DHEL)
M. JINNO, Y. MUGURUMA, T. MATSUDA, H. MOTOMURA and S. TAKUBO
55
Optimal Pulse Voltage Waveform for a Xenon Barrier Discharge Lamp using both an Inner Electrode and an External Electrode
M. JINNO, H. TANIUCHI, M. WATANABE and H. MOTOMURA
58
Spectroscopic Measurement of Faint Light Produced by Rapid Separation of an Adhesive Tape
K. KADOWAKI, S. NISHIMOTO and I. KITANI
61
A Dimmable Electrodeless Fluorescent Lamp
Y. CHEN, Q. LONG, D. CHEN, W. LI and A. WANG
64
Sustainable Lighting and Sense-Rich Environments
H. WILLEY
68
Assessing Daylighting Performance of Buildings Using Orthographically Projected Area of Obstructions
T. CHUNG and H. CHEUNG
74
Temporal VUV Emission Characteristics Related to Generations and Losses of Metastable Atoms in Xenon Pulsed Barrier Discharge
H. MOTOMURA, K. H. LOO, Y. IKEDA, M. JINNO and M. AONO
81
Visual Impression of Lighting from a Window and a Ceiling: a Comparison between the Compound Lighting and the Uniform Lighting
S. HAN, T. ISHIDA, M. IGUCHI and W. IWAI
87
Discomfort Glare Caused by White LED Light Sources
T. KASAHARA, D. AIZAWA, T. IRIKURA, T. MORIYAMA, M. TODA and M. IWAMOTO
95
Light is vital for life: Light sources play an indispensable role to daily life of any Human being. Our World cannot be conceived without light. Quality of life, health and, somehow, urban security related with traffic and crime prevention measures depend on light and on its quality. The lighting industry is an important economic factor in Europe, USA and many Asiatic Countries. All in all, lighting is an important socio-economic factor and lighting system development should be an integral part of any Sustainable Development and of any program of improvement of Quality of Life. This presentation provides an overview of the present state of research in the science and technology of light sources. Existing technologies and future challenges for the lighting industry will be presented. To better understanding the light source technology an part of this presentation will be devoted to the physics of light sources.
KEYWORDS : light sources, science and technology, energy savings
Recently as interests in environmental issues increase, demands for mercury-free fluorescent lamps are increasing because mercury is harmful to human beings and creatures. As one of the solutions of this issue the authors have developed a new-type of mercury-free fluorescent lamps using double helical external electrodes. In this paper the fundamental characteristics of Xenon-Neon discharge in the Double Helical External Electrodes Lamps (DHEL) such as the luminance, power consumption and lamp current are investigated. When the pressure ratio of Xe : Ne was fixed at 7 : 3, total pressure at 1.33 kPa and external electrode pitch as 10 mm, luminance over 10000 cd / m2 is achieved. In addition as a prototype 1 m length DHEL is prepared and demonstrated to show basically there is no limit in length of DHEL.
KEYWORDS : barrier discharge, mercury-free, fluorescent lamp, xenon, external electrode, DHEL
When applying a pulsed voltage to a discharge tube using dielectric barrier discharge, discharge occurs two times in a pulse at a rising and a falling edge of a voltage pulse. The timing of the second discharge can be changed by controlling the pulse width. In this study the influence of the pulse width on the luminance of the barrier discharge lamp with an inner electrode is investigated. The lamp used in this study has two electrodes, one is set in the lamp and the other is set on the outside surface of the lamp. Internal electrode is connected to the high voltage side and the external electrode is connected to the ground side. Luminance is observed under the condition of pulse repetition frequency of 10 kHz, peak voltage from 1 kV to 3 kV and pulse width from 2µs to 98µs. Luminance took almost same value from 30 µs to 90µs, whereas it decreased by both deceasing the pulse width less than 30µs and increasing it more than 90µs. It means that the higher luminance is obtained by avoiding the overlap of the two radiations at rising and falling edge of applied voltage.
KEYWORDS : dielectric barrier discharge, pulse width, xenon, fluorescent lamp, mercury-free
This paper describes results on an experimental study of faint light emission produced by separation of an adhesive tape from a glass or from a polymer film. Spectroscopic measurements of the faint light were carried out using a monochromator and a photomultiplier. The results indicated that the light emission was caused by discharges near the tape-air-glass triple junction. We found that the frequency of the light emission was strongly changed by changing the peeling speed of the tape. Discharge lights were detected in many times in the case of high-speed peeling, whereas no light was detected in the case of low-speed peeling. We also measured surface potential distributions on the film after separation from the tape using a XY-movable probe and an electrostatic voltmeter. The surface potential on the film after the fast-speed peeling became slightly higher than that on the film after the low-speed peeling.
KEYWORDS : adhesive tape, discharge, peeling speed, electrical double layer
A dimmable electrodeless fluorescent lamp (induction lamp) is introduced in this paper. The principles of the induction lamp are introduced in details. A dimming approach for the lamp is discussed in both theory and experiment. A continuous dimming range from 30%-100% can be realized with the application of the IC chip.
KEYWORDS : electrodeless fluorescent lamp, IC chip, dimming
Sustainable lighting, considered in the broader context of sustainable design, suggests a return to more natural interior environments with their greater sensory stimulation and experiential richness. Research over the last 50 years has been claimed to provide little evidence of the interaction between the visual, thermal, acoustic, tactile and olfactory senses which might be expected to be essential to sensory richness. A critical evaluation of such research, in the context of understanding gained from recent research in cognitive science and neuroscience, reveals serious flaws in this research into sensory interaction. The nature of these flaws is discussed with examples. Insight gained from studies of visual perception suggests significant changes need to be made to experimental procedures to avoid the problem of “inattentional blindness” and to overcome the lack of reality in the rooms and equipment used in laboratory-based studies. In particular, it is argued that the lack of a sense of “place” and of a realistic activity means that the experimental setting will fail to trigger any significant activity in the neural pathway in the visual cortex which has been found to enable interaction with non-visual sensory modalities.
KEYWORDS : sustainable lighting, cognitive science, neuroscience, inattentional blindness, interactive vision
Recently the Hong Kong Government has issued a performance-based code governing daylighting in buildings to supplement its prescriptive code. The performance-based method uses the vertical daylight factor (VDF ) at the centre of the window pane in the specification of the performance standards. However, the calculation of VDF is not an easy task and is especially not suitable in the early design stage when designers may need to evaluate the daylighting performance quickly using simple sketches and limited data. In view of this, the current performance-based code allows the use of a simplified alternative method called the unobstructed vision area (UVA) method. In this paper, a review of the UVA method is first given. Then a method based on the orthographically projected area (OPA) of all obstructions above the reference point is presented. The OPA can be determined with similar efforts as determining the UVA. Case studies comparing the performance between the OPA and UVA methods are presented. Results show that the OPA method predicts the VDF reliably and therefore is truly a simplified performance-based method.
KEYWORDS : daylighting performance, vertical daylight factor, unobstructed vision area, orthographically projected area, obstructions
Although xenon pulsed dielectric barrier discharge is one of the most promising substitutes for mercury low-pressure discharge for fluorescent lamps, the efficacy of xenon fluorescent lamp is not enough for practical use for general lighting. To improve the efficacy it is indispensable to clarify mechanisms of vacuum ultraviolet (VUV) emissions, which excite phosphor, from xenon discharge related to plasma characteristics. In this paper emission waveforms and temporal change of metastable atom density are measured and temporal VUV emission characteristics related to generations and losses of metastable atoms in xenon pulsed barrier discharge is investigated. It is shown that the lamp efficacy is improved by about 10% with shorter pulse in which the two VUV emission peaks in a pulse are overlapped. It is also shown that at the lower pressure of 1.3 kPa metastable atoms generated during on-period of the voltage pulse are not efficiently consumed for VUV emissions in the off-period of the voltage pulse because of lower rate of three-body collision and quenching. This fact is thought to be one of the reasons why the lamp efficacy is low at lower pressure.
KEYWORDS : VUV emission, metastable, xenon, mercury-free, fluorescent lamp, dielectric barrier discharge
The purpose of this study is to understand the change of impression by comparing the uniformity lighting with the compound lighting. The experiment is carried out with the two scaled-models that were supposed to be an office space. One is lit by the uniform lighting and the other by the compound lighting. Subjects were asked to evaluate the point of difference by semantic differential rating on their overall impression after comparing with two rooms. The results showed that the impressions of compound lighting were more positive score than that of uniformity lighting on the items of ‘dim-bright’, ‘dislike-like’, ‘artificial-natural’ and ‘closed-open’, and that there was no significant difference in impressions between two spaces on other items.
KEYWORDS : visual impression, comparison method, compound lighting, uniform lighting
It is expected that lighting employing white LED will become popular in the future. However, the influence of the arrangement as well as the number of LED lights and luminance distribution of the surface of light sources on discomfort glare has not yet been clarified. The aim of this study is to clarify such influences by conducting an experiment using simulated light sources. The results of the experiment show that the closer the ratio of luminance of the peripheral area against luminance of the LED lighting (luminance of the peripheral area / luminance of the LED lighting) is to 1, the smaller the discomfort glare. It is also clarified that when the total area of the light source is constant, although the BCD average luminance increases as the number of LED lights increases, the level of increase in the BCD average luminance is smaller than that in the number of LED lights. Further, when the interval of LED lights is constant, it is found that although the BCD average luminance decreases as the total area of the light source increases, the level of the decrease is smaller than the level of the increase.
KEYWORDS : discomfort glare, white LED, BCD luminance, UGR, average luminance