JOURNAL OF THE ILLUMINATING ENGINEERING INSTITUTE OF JAPAN
Online ISSN : 1349-838X
Print ISSN : 0019-2341
ISSN-L : 0019-2341
Volume 81, Issue 8
Displaying 1-11 of 11 articles from this issue
  • Haelim Yoon, Mitsuo Ikeda, Hiroyuki Shinoda
    1997 Volume 81 Issue 8 Pages 621-627
    Published: August 01, 1997
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    Continuity perception between two spaces can be obtained in general by adjusting the illuminance level of one of the spaces, when we say that the recognized visual spaces of illumination of the twospaces were made equal. This continuity can be experienced, for example, when an observer in a room looks outside through a window and the illuminance of the room is properly adjusted. There exists a range of illuminance within which continuity perception is assured. In the present experiment the range was measured when the color temperature of the room was systematically changed so that there were various differences in the color temperature between the room and the outside. The experiment was carried out during day time, and the weather outside varied greatly both during and between the experimental sessions. The results show that the range, when expressed in a specific form of outside illuminance and room illuminance, was constant regardless of the color temperature difference. The upper limits as well as the lower limits of the range slightly increased as the color temperature of the room became lower than that of the outside.
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  • Tadao Uetsuki, Noriyuki Taguchi
    1997 Volume 81 Issue 8 Pages 628-637
    Published: August 01, 1997
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    The performance of a Ne-Hg negative glow lamp (having no positive column) was measured at different frequencies. The results showed that the efficiency decreased as frequency increased. The plasma characteristics were measured by a Langmuir probe and spectroscope to analyze this phenomenon. The following results were observed:
    1. There were two groups of electrons, first electrons and second electrons, in this plasma, and there was a period without first electrons at high frequency.
    2. The energy of the second electrons at high frequency operation is lower than at low frequency.
    3. Peak energy of the first electrons at high frequency operation is higher than at low frequency.
    From these results we attribute the reason the efficiency of this lamp becomes lower at high frequency to the following.
    (1) The energy of the second electrons at high frequency operation is lower than at low frequency because the second electrons, which can get the energy only from electron-electron collision, but cannot get energy in the period without first electrons.
    (2) Ionization loss at high frequency operation is higher than at low frequency because the peak energy of the first electrons at high frequency operation is higher than at low frequency.
    Lastly the performance of negative glow, in a Ne-Hg lamp and Ar-Hg lamp with a positive column, was checked by observing the spectrum. The measurement results shows that there was no discrepancy to the conclusion that the peak value of cathode fall voltage at high frequency operation is higher than at low frequency.
    It has been reported that the cathode fall voltage at high frequency operation is lower than at low frequency. In this paper we found out that the m.r.s. of cathode fall voltage at high frequency operation was lower than at low frequency, but that the peak value of cathode fall voltage at high frequency was higher than at low frequency.
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  • Influence of HUD Luminance, Observer's Age, and Actual Driving
    Kazumoto Morita, Jin'ichi Mashiko, Takeo Okada
    1997 Volume 81 Issue 8 Pages 638-647
    Published: August 01, 1997
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    Since the image of an automobile head-up display (HUD) overlaps with the scenery in front of the vehicle, this may be considered to be troublesome for drivers. We have already revealed the basic relationship between display position and a feeling of troublesomeness by conducting experiments outdoors. In this research, we carried out indoor experiments to clarify the influence of factors such as luminance of the HUD and observer's age on a feeling of troublesomeness. As a result, we found that older observers feel much troublesomeness in a position directly in front of them. We also carried out outdoor experiments, in which the observer was actually in a car and a mock-up HUD making use of clear film was used. We investigated how the feeling of troublesomeness changed depending on whether the vehicle was stopped or moving. We found that while driving, the observer was likely to feel much troublesomeness at display positions on the left side. This is probably because the distribution of the line of vision of the driver moves toward the left when driving in Japan (where one drives on the left.)
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  • Hajimu Nakamura, Masayuki Iguchi
    1997 Volume 81 Issue 8 Pages 648-655
    Published: August 01, 1997
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    The main purpose of the work described in this paper was to develop a new lighting design technique to help create a pleasant or comfortable indoor lighting environment. Subjective appraisal was studied, using the semantic differential method on impression given by the stimulus of perspective drawings which have various shape and array of luminaires on ceiling.
    At the first experiment, numerical values of data was processed by correlation analysis between harmonious/unharmonious and other scales, and yielded the following results: Three scales affected harmonious/unharmonious in order of strongness of effect, such as too large/too small, the impression on area size of luminaires, too many/too few, the impression on number of luminaires, too narrow/too wide, the impression on distance between the edge of the luminaire and the neighbor one. In the relationship between rating of impression and value of physical factor, the result of subjective appraisal in real buying space had similar trend as the above result.
    At the second experiment, authors studied on the factor analysis concerning the atmosphere realized by the stimulus. It was clarified that the important factors were harmony, unusualness and activity. Square luminaires tended to realize more unusual atmosphere than rectangular ones.
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  • Yasumitsu Fujisawa, Mamoru Hashimoto, Tsutomu Araki
    1997 Volume 81 Issue 8 Pages 656-663
    Published: August 01, 1997
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    Temporal emission characteristics of light emitting diodes (LEDs) for high-speed repetitive current have been investigated. For this purpose, three commercially available LEDs (red, green and blue LEDs) were prepared. Each LED was driven by a specially designed pulse generator constructed using an avalanche transistor to generate high-speed pulse current. Resultant injection current showed a nanosecond duration pulse with peak height of a few amperes. Time responses and spectral profiles of the emission waveforms were measured with respect to the pulsed current. Resultant light durations of the pulsed LEDs were in the nanosecond range. When the injection current increased, the peak emission intensity of the LED increased without saturation. In particular, the ultraviolet component of the blue LED became evident, resulting in peak emission intensity of 30 m W with duration of 5 ns. Lifetime of the pulse-operated LED was over 1O 10 shots, which corresponds to 140 hours running at repetition frequency of 20 kHz.
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  • Yukitaka Shinoda, Takashi Higo
    1997 Volume 81 Issue 8 Pages 664-670
    Published: August 01, 1997
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    We intend to make a coherent heterodyne light source that oscillates at a low beat frequency which has a simple structure and is easy to handle.
    The frequency of light waves can be shifted by the doppler effect, which occurs in swept along the length of the movable arm of a polarization interferometer.
    This paper showes how to make a heterodyne light source by retardance modulation based on this method.
    Next, we present an application of the trial manufactured heterodyne light source to visualization of the distribution of responsivity on the photodiode's surface and the electrode's position by optical beam induced curennt, and the measurement of small displacement in a nano meterscale region by the heterodyne interferometric method.
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  • Tatsuo Shiina, Koichi Ikeda
    1997 Volume 81 Issue 8 Pages 671-678
    Published: August 01, 1997
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    In bad weather conditions e. g. rainy, foggy and snowy conditions, exact slant visual ranges should be obtained for safe landings at airports. However no equipment for achieving this has been installed in airports yet.
    In this study, the laser radar system is developed for estimating the slant visual range. It is found that the practical data in bad weather conditions do not correspond to the predictions of the current laser radar equation. Therefore, the new laser radar equation, which considered the divergence of transmitting laser beam, is proposed. The slopes of this equation correspond well to the practical data in various weather conditions. The visibilities estimated by this equation also coincide with those obtained by the slant transmittance system. And the extent of the divergence is examined by means of classifying the practical data by weather conditions. As a result, it is found that the divergence of the transmitted laser beam increases in the order of rain, fog, misty rain, and snow.
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  • Factor Analysis of the Time Required to Read the Name of the Destination among Multiple Place Names
    Kazumoto Morita, Jin'ichi Mashiko, Takeo Okada
    1997 Volume 81 Issue 8 Pages 679-685
    Published: August 01, 1997
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    I ndoor experiments were carried out to investigate the legibility of navigation information displayed by in-vehicle navigation devices. Observers were asked to judge whether the destination name was included among the multiple place names presented. To determine the time required for shifting the line of vision and that for accommodation, we set the experimental conditions so that the observer moved his/her line of vision away from distant scenery (5.6meters in front) or from nearby scenery (0.75meters in front) toward a navigation display device located to his lower left (0.75meters away from his/her eye.) The reading times were measured and compared under these conditions. Furthermore, the observers were divided into two groups: a younger group in their2Os and an older group in their60s.
    Results show that the time for shifting the line of vision ranged from 0.3 to 0.4 seconds measured from the time a buzzer was sounded simultaneous with the information being displayed. Observers in their 2Os finished accommodation roughly at the same time as completing the shift of the line of vision. On the other hand, those in their6Os required for longer accommodation.
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  • Hajimu Nakamura, Yoshinori Karasawa
    1997 Volume 81 Issue 8 Pages 687-694
    Published: August 01, 1997
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    A residence is a place for various living activities, for which a variety of lighting conditions should be studied including a general lighting illuminance, illuminance distribution, luminance, luminance distribution, color rendering properties and color temperature, to achieve a preferable atmosphere with suitable lighting. Selecting two factors of illuminance and color temperature, the effect on the atmosphere was scientifically studied. The experimental study of subjective appraisal with semantic differential method was carried out, using the experimental equipment developed to simulate various combinations of illuminance and color temperature.
    Observers were asked to make their appraisals by first participating in an imaginary scene involving an enjoyable conversation with family and/or friends and next by imagining themselves in a relaxed state drinking coffee alone. The first scene applies to a state that we shall refer to as the communal state, and the second scene as the solitary state.
    Analysis was performed on the results of how the preference changed with the adjustments of illuminance and color temperature. For the communal state, atmosphere preference grew with the increase of illuminance within the range between 1001x and 4001x, and was saturated at higher illuminance levels. For the solitary state, preference was not so proportionally related to illuminance, and observers expressed a little dislike for high illuminance levels in comparison with low illuminance. The first activity preferred higher illuminance level and the second activity preferred lower illuminance level. The results above were compared with Kruithof's.
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  • Hiroyuki Shinoda, Mitsuo Ikeda, Masato Niimoto
    1997 Volume 81 Issue 8 Pages 695-699
    Published: August 01, 1997
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    Colored surfaces appear brighter than expected from their lightness and the discrepancy has been solved by replacing the lightness by the equivalent lightness defined by the brightness perception. The equivalent lightness increases with illuminance level under which the surfaces are observed. This concept was introduced based on the heterochromatic brightness matching between a colored surface and a grey scale, and to be useful in daily life it should be proved to be the dominant factor determining the overall impression of a picture which is a complicated composition of colored surfaces. In this experiment a colored picture was evaluated by a series of grey-scale pictures in terms of overall impression under various illuminance levels. The most similar impression was obtained with a grey-scale picture composed of picture portions similar to the colored picture in the equivalent lightness. This indicates that the equivalent lightness is the dominant factor determining the impression of a colored picture.
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  • Yoshihiko Tabuchi
    1997 Volume 81 Issue 8 Pages 700-702
    Published: August 01, 1997
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
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