Relative density distributions of particles at excited levels are estimated in fluorescent lamps having oblate cross sections (aspect ratios of 0.4-1.0). Since the plasma in such a fluorescent lamp does not have cylidrical symmetry, a new computed tomo graphic (CT) technique, which is applicable to a spatially non symmetrical shape, is used to measure emission intensities from optically thin levels. Reflection and refraction at the surface of the tube are calibrated by their first order components. From the measured values of electric field strength, electron energy distributions and density distributions of particles at excited levels including optically thick levels are calculated. On the major axis, the distributions of excited levels emitting visible lines sag under the Jo distribution, and on the minor axis, they are bullet shaped. These distributions depend heavily on its tube aspect ratio and not on its current.
This paper describes a new approximate calculation of interreflection in a room containing fixtures. In the conventional calculation for interior lighting which is based on luminous flux transfer, the number of form factors and hence the computation time increases with the number of surface elements. For this evaluation, the illuminanceof each surface in the room calculated vary in fixture type, fixture height, and fixture reflection factor. We present results that the approximate values have strikingly good agreements with the exact values for the average illuminance and illuminance distribution of all surfaces, and the computation time is much shorter.
The empirical formulas introduced in our previous paper to calculate the equivalent lightness of colored surfaces when their Munsell color notations were known had a problem with the contribution of hue to the chromatic lightness particularly in the region of hue 5Y. We present a new formula for hue coefficient h (φ). The revised formula for equivalent lightness nicely describes our old experimental results and our new ones making it useful in predicting the equivalent lightness of any colored objects if they are specified by the Munsell color notations. As additional experiment, the color naming experiment was conducted for the color charts used in the equivalent lightness experiment and the chromatic lightness was found to be mainly determined by the amounts of unique hue components, red, green, and blue, but not by yellow.
In the CIE TC3-13 meeting in 1993, the unified glare rating (UGR) proposed by K. S φresen was approved for adoption in the TC report. In Japan, the “G-Classification” which classifies luminaires based on the CIE Glare Safeguard System, has been used. Therefore, it is important to clarify the relationship between the “G-Classification” and UGR. This paper analyzes the relationship between them using calculations for nine typical luminaires and establishes that there is a clear relationship between them. However, UGR has a significant problem. It was developed based not on observations, but on calculations that merely simplify and make more consistent the previous glare evaluation methods. Thus there is no observation data to proveits accuracy. The second part of this paper presents studies done to clarify the relationship between the subjective appraisals of discomfort glare and UGR. Using a full-scale office model where various lighting conditions could be presented, the degree of discomfort glare was evaluated by many observers, and the relationship between the evaluations and the calculated UGR was analyzed. The results show that although there is a certain relationship between them, the degree of discomfort glare obtained by the subjective appraisal is lower than the value calculated for UGR.
In the operating circuits of high pressure mercury arc lamps of various ratings, the voltage and current characteristics of the lamps exhibit some analogous properties inherent in their respective characteristics pairs. In this paper, we first replace the lamp, treated as a circuit element by a equivalent conductance. Then, based on the model constants of the equivalent conductance of the lamp's operating circuit having specified ratings, we obtain from the analogous properties of the lamp's voltage and current characteristics the corresponding model constants of the equivalent conductance for the lamp in operating circuits having various other ratings. This makes possible waveform analysis of the voltage and current characteristics of each circuit element by simulation, which is described in this paper.
A new band-spectral solar ultraviolet-B (UV-B: 290-320 nm) radiometer is developed for easy and accurate outdoor measurement. The spectral response of the radiometer is a maximum at 305 nm and has a 20-nm bandwidth. In this radiometer, incident global solar UVB irradiance is converted to visible light by a phosphor layer and is detected by a Si-photodiode. The spectral, cosine, azimuth, and temperature responses of the radiometer are evaluated. Contamination by the UV-A irradiance longer than 320 nm is less than 6% of the measured UV-B irradiance. No changes in the instrumental constant or in the spectral responses of the radiometer were found by periodical checks over a two-year period. Results indicate that this radiometer is useful for continuous, high time-resolution measurement of global solar UV-B irradiance.
The behavior of gaze in the task of color matching was studied at various stimuli separations from 6 to 120 deg. for two subjects. Eye and head positions were measured with a limbus tracker and a CCD camera attached to a pair of spectacles. Whereas the time required per match was almost constant, the number of gaze shifts decreased and the fixational duration increased with stimuli separation. This indicates a change in the strategy in the visual system. For one subject, head rotation started at 30 deg. separation and for the other at 15 deg. separation. Whenever the subjects' head rotated, vestibulo-ocular reflex (VOR) occurred after eye saccade. Moreover, at 60deg. separation or more, pre-saccade VOR and multiple saccades were observed. The time duration for gaze shifting increased with stimuli separation, but at larger separation angles the slope of the time duration increase curve became gentler.
The Magnetic Semiconductor Photodetector (MSP) is a 40-μm-thick transducer with a magnetic semiconductor film that is composed of MnO, ZnO and Fe2O3 and that has a surface painted with a radiant flux absorbent. Incident light increases the MSP temperature, increasing the MSP's magnetic reluctance. The magnetic density variation in the MSP is read out by a Hall element. MSP patterns can be printed on the substrate in various shapes (such as a plate, a ring, or a rod), and the MSP is suitable for use as a photosensor, a photochopper, a photorelay, or an exposure meter. Preparation techniques, pyromagnetic characteristics, and the light signal read out are discussed here.
A color matching task was done by one subject repeatedly to study color discriminability as a function of inter stimulus interval (ISI) in successive stimuli presentation. Reference and matching stimuli were presented alternately with a certain ISI (0-1000 msec.) The subject adjusted the color of the matching stimulus to match the color of the reference stimulus while switching their presentation at will. The distribution of matching points was assessed by an ellipsoid in xyY color space. The size of the ellipsoid was constant in spite of the ISI increase, but was nevertheless larger than that obtained in simultaneous presentation. The fact shows that the time interval between successive fixations was not a primary factor of low discriminability for spatially separated stimuli.
Electrotechnical Laboratory has established a standard of spectral response at 633 nm based on the self-calibration of a silicon photodiode and an absolute radiometer (operating at room temperature). The standard was maintained a windowed silicon photodiode and transferred by a calibration system using a monochromator. The change in the response of the windowed silicon photodiode was 0.04% over five years. The accuracy of this standard was verified through three international comparisons: the first one organized by CCPR in 1986, the second by CIE in 1988, and the third by CCPR in 1992. The uncertainty of the standard is estimated to be 0.2%.