In recent years, windowless office spaces have increased remarkably, while problems related to windowless roomsremain to be solved.
This study was conducted to evaluate the effects of visual environment on human psychology and behavior in a windowless office space.
This thesis consists of three Experiments which are stated below.
In Experiment 1, using scale models, at first the psychological factor structure of the visual environment of a windowless control room, which is the typical windowless office room, are surveyed. Secondly the relationship between psychological factors and physical factors which constitute visual environment are examined.
In Experiment 2, how the visual environment affect subjective appraisal and human behavior such as eye movement, task performance and behavior pattern, in windowless office spaces are disscussed, when subjects were at fundamental task in an actual sized experimental space.
In Experiment 3, how visual environment and types of task affect human psychology and behavior such as subjective appraisal, task performance, behavior patterns in windowless office spaces are examined, when subjects took six types of task, which were chosen to take usual work at an office space into consideration, in the same experimental space.
Summing up the results obtained above, we conclude that although the visual environment of the windowless office space have negative influence upon human psychology and behavior, they can be compensated by considering interior decoration and types of task.

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In the preceding paper, we investigated driver's ability to recognize Head-up Display (HUD) images and the forward view comparing to Head-Down Displays (HDDs) by in-laboratory experiments. Recognizability of HUD images can be enhanced by setting the distance between driver's eyes and displayed images long, though the recognizability of the forward view does not depend upon the distance.
In this paper to verify the results, we have carried out two kinds of experiments using HUDs and a HDD installed in an experimental vehicle under actual running conditions. One is sensory evaluations of HUDs, and the other is measurement of eye fixation time for recognizing displayed images.
In recognizing displayed images and the forward view, the results of both the in-laboratory experiments and the actual vehicle experiments well match with each other.
HUDs can shorten the fixation time under all running conditions. For the recognizability of the HUD images, the increase in distance to the images improves the driver's recognizability. This is also true under actual running conditions, however, when the vehicle runs in city roads at low speed, the effect of moving vehicle brings in new factor that should be taken into account for optimizing the distance. The performance of HUDs that is related to this factor deteriorates when the distance increases.
It is concluded that the new factor should be traded off with the recognizability of HUD images to optimize the distance.

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It is well known that older people are more sentitive to discomfort glare than young people. This sensitivity is one of the visual problems that go with aging. On the relationship between discomfort glare and an observer's age, Bennett has already reported that older people produce lower BCDs (Borderline between Comfort and Discomfort) than young people. It is also known that the discomfort glare is affected by the color temperature of the light sources used, but this effect has not been clarified quantitatively.
In order to clarify the quantitative relationship between the discomfort glare and the color temperature of light sources, we conducted a series of experiments on the discomfort glare for light sources with different color temperatures. The results are as follows (1) Both old and young observers are more sensitive to discomfort glare for the light sources with high color temperatures than for those with low color temperatures.(2) The effects of the color temperatures on the discomfort glare are about the same for both old and young observers.(3) The spectral distribution of light sources has no effect on the discomfort glare, if these color temperatures are constant.

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Legibility of VDT using LCD was evaluated compared with the VDT using CRT. The display luminance, contrast and chromaticity of the color LCD and CRT were examined under the different illumination. The LCD with back lighting system, which was used in emissive mode like CRT, showed less washedout and better legibility than the CRT under high lighting condition. The LCD with the display luminance of only 120cd/m² in white was readable under high lighting condition of 100000 lx. The variation of the display contrast and chromaticity was less than CRT, when the luminous intensity was changed. These were due to the lower diffusive reflectance of LCD compared with CRT. The variation of the display contrast was dependent on the diffusive reflectance of light shield mask, which was formed in the color filter of the LCD panel. It was concluded that the variation of the contrast was expected to be more improved using the mask with lower diffusive reflectance, which was made of zelatin insted of chromium. It was declared that the LCD was suitable for the use under the bad lighting environment, i.e. for outdoor use.

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Average illuminance is a guide to judge the quality of lighting, and it is necessary to predict the average illuminance on working plane after interflection in the design of interior lighting.
Calculation of the average illuminance on working plane used in the design of interior lighting is formed on an assumption that the space between the plane of the luminaries and the working plane is empty, but in practice most interiors contain room fixtures.
Therefore, the authors calculated the average illuminance on such working plane with fixtures which varied in height, position and reflectance. The result showed the effect of room fixtures on the average illuminance on such working plane.
Furthermore, this paper presents approximate calculation method of the average illuminance on such working plane, and the approximate calculated results agree well with the conventional calculated results in the average illuminance and illuminance distribution on working plane.

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Spectral diffuse reflectance and radiance factors of pressed polytetrafluoroethylene (PTFE) powder produced in Japan have been measured with variation of density, thickness, surface roughness, wavelength and ageing effects of the pressed powder. The 0°/d spectral diffuse reflectance was measured over 250 to 2500nm region. The radiance factors were measured at 0°and 45°incidence and at-80°to 80°viewing angles, on wavelength of 400nm, 550nm, 700nm, using an absolute goniophotometer. It has been found that, although slight ageing effects and weak fluorescence in UV region are recognized, the newly pressed powder has high reproducibility on diffuse reflectance and radiance factors under a certain range of pressing condition, and that the pressed powder will be useful for the radiance factor's standards as well as the diffuse reflectance standards.

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To detect the amount of Oxygen (O₂), existing in conventional incandesent lamps as impurity, we have investigated light spectra with discharging them. The total pressure is 93000 Pa (Ar90%, N₂10%) and O₂ content is iess than 250PPM.
Though any significant dependence of spectrum decaytime on the O₂ content is not found from Ar and N₂ gas, large dependence on the O₂ is found from O (¹S) Ar excimer formed in the discharge, i. e., while 0₂ content is less than 50 PPM, R (R; attenuation constant [1/sec]) of the spectrum from the excimer increases in proportion to O₂ content. The measured decaytime fits a calculaion using the equation of Welge and Atkinson. While O₂ content becomes more than 50 PPM, R increases with the third power of O₂ content. The reason of this higher rate may be related to production of 0₃.
With checking time dependent behaviour of the excimer spectrum, it becomes possible to detect the amount of O₂ in conventional incandescent lamps without destruction of envelopes.

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By means of a newly developed analytical method applying the via-perspective method, equations to calculate various spacial illuminances by means of flat surface sources with an arbitrary shape and at arbitrary location have been able to develop.
When calculations are achieved by using the equations, it has been clarified that the error in the rough calculating method to obtain a spherical illuminance by average of six-directions-illuminances becomes very large when an angle subtending a flat surface source is small.
However, assuming a twenty-six minute face pieces interpolated at 45 degrees, it has been clarified that the degree of error may be significantly improved by adopting a method to average the values obtained by multiplying respectively the illuminance of each face by area ratio of each face.

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The present report describes the effects of light sources and color elements (hue, value, and chroma) of chairs on the atmosphere in a living room. A life-size model about 3.5m in width and length was used as an experimental room. The illuminance on the center table was adjusted to 200 lux.
24 seven-point semantic deferential rating scales were used in this experiment.
The evaluation of the atmosphere in the living room tended to correlate with Activity more clearly as lowering the color temperature of light source by using principal component analysis.
A mutual effect of light sources and hue of chairs on activity and that of light sources and chroma of chairs on evaluation were found.
Incandescent lamps and three-band type incandescent-colored fluorescent lamps effected on making the atmosphere more comfortably.

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When we indicate or describe an object in everyday lives we often use a color of the object. Although there are a million of colors around us we do not use so many colors, but categorize defferent colors into several color names. Eleven color names; red, green, yellow, blue, brown, orange, purple, pink, white, black and gray, have been qualified as basic color categories, that are used consistently among observers and occasions. In this study we measured categorical regions in a color space determined with a categorical color naming method using these 11 besic color names. Two color-appearance modes; aperture color mode and surface color mode, were tested. We employed both a color CRT monitor and a OSA uniform color scales set as test stimuli in the two color-appearance modes. It is shown in our results that both aperture and surface color spaces were consistently divided into the 11 basic color categories, and that positions and borders of color categories depend on luminance (lightness) of test stimuli in the surface color mode, but almost independent on luminance in the aperture color mode. Furthermore, test stimuli made by a color CRT do not appear so different from those by color chips in both color-appearance modes. There are some similarities between our results and the Kelly's chart.

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The illuminance of meeting attendees' faces is one of the most important values for visual tasks in the modern office. A series of experimental studies, with subjective appraisals, were carried out to determine the preferred face illuminance versus the illuminance of the visual task area on a desk.
In previous studies, background illuminance was set at the lower limit value of about 90% cumulative occurrence rate of desk illuminance; then, the background illuminance was changed simultaneously with the desk illuminance. Because of this, the influence of varying background illuminance when desk illuminance is held fixed, or the influence of varying desk illuminance when background illuminance is held fixed had not been determined yet.
In this study, background illuminance and desk illuminance are changed independently of each other. In addition, experiments were conducted to compare face illuminance to desk illuminance in one case and in the other case the face illuminance was observed without comparing it to desk illuminance. The latter two experiments were conducted to see in more detail the effects of desk illuminance on visual tasks.
The results are as follows:
1. There is very little relationship between the optimum face illuminance value and the background (wall) illuminances.
2. There is also very little relationship between the optimum face illumination and background (wall) luminance, including wall reflectance.
3. Whether face illuminance is compared to desk illuminance or not, the optimum face illuminance is in logarithmic proportion to the desk illuminance.
When face and desk illuminances are compared, the optimum face illuminance is more related to desk illuminance than not.
According to conventional theory, optimum face illuminance should be affected by background (wall) illuminance. However, the studies show that the illuminance of the desk in front of the observer has more influence on the optimum face illuminance.

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For reflecting or transmitting object colours, the CIE tristimulus vslues of a colour stimulus are obtained by multiplying, at each wavelength, the value of the weigthing factors by that of each of the spectral reflectance or the spectral transmittance of the object colour. Then each set of products is integrated over the wavelength range corresponding to the entire visible spectrum, 380 to 780nm. The integration may be carried out by numerical summation at a wavelength interval, equal to 5nm. The weigthing factors are obtained by multiplying, at each wavelength, the value of the relative spectral power distribution of the illuminant by the CIE colour-matching functions.
In practical applications, all the required data may not be available because of measurement at greater intervals intervals than 5nm, equal to the 10nm or 20nm intervals data. In this paper, the method for the calculation of the weigthing factors for the 10nm or 20nm intervals measurenent data using interpolation is reported.

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