Illumination Engineering Research Articles

Compensating converter with photodiode

1. The compensating converter with the photodiode makes it possible to attain higher accuracy of measurements of quantities of illumination engineering than in measurements making use of direct conversion methods; the design of the primary converter is rather simple but dependable in operation. 2. In order to increase the accuracy of a converter of this type, measures must be taken to restrict the range of temperatures at which the photodiode is operated to the interval in which the condition r≪R0 is satisfied.

Interchange Illumination—Engineering and Economics

In order to clarify certain aspects of high mast lighting design, this paper reviews and analyzes interchange illumination based on equivalent design criteria, and subsequently determines how mounting heights influence the engineering and economics of such installations. /HSRI/

Impressions of the Session (Pertaining to Subcommittees on Colorimetry, Color Rendering and Illumination Engineering Materials.)

Impressions of the Session (Pertaining to Subcommittees on Colorimetry, Color Rendering and Illumination Engineering Materials.)

Panel Discussion-Future of Illumination Engineering and Its Relations to Associated Fields

Panel Discussion-Future of Illumination Engineering and Its Relations to Associated Fields

A Spectroradiometer for the Spectral Region of Biological Photosensitivity

The instrument described was specifically designed for measurement of the spectral irradiance of lighting in experimental plant growth chambers. However, without modification it is usable for experimental light source measurements and for illumination engineering applications. The spectroradiometer is basically composed of a motor-driven grating monochromator with suitably adapted multiplier phototube, amplifier, and strip chart recorder. The spectral region covered extends from 350 nm in the near uv to 850 nm in the near ir. Included here is a discussion of the desirable characteristics of spectroradiometers for this application.

Terms and units used in the measurement of the intensity of optical energy

The expanding areas of interest of people engaged in electro-optical work leads many into contact with unfamiliar terms and units. This article presents the terms employed in the measurement of the intensity of optical energy employed by physicists, astronomers, and illumination engineers. Factors for converting between systems are presented.

RADIATION MEASUREMENT IN PHOTOBIOLOGY — CHOICE OF UNITS

Abstract— The physical units most commonly used in photometry have limited value outside the field of illumination engineering. They tend also to conceal rather than display the physical concept of radiation as understood at present.Only by making the concepts of quantum theory accessible by a fundamental change of units, can those concepts make their full contribution to photobiology.The paper suggests adoption of the quantum as the unit of intensity and the electron volt as the specification of spectral quality, thus bringing the nomenclature of photometry into line with other branches of radiation physics. A start is made with definition of some of the essential derived units, source intensity, irradiation, and flux.

A Designing Method of Reflector and Projector Lamps

A designing method of reflector or lens contours for reflector and projector lamps is attemped. It has been customary, in illumination engineering, to use simple second-degree or composed surfaces for these designs, but this time we introduce a new method to calculate directly matched surfaces in the caces of various reflector type lamps and desirable light distribution.The reflecting or refracting law exists at any arbitrary points on the unknown desirable surface, and the differential eqation between directions of light and the function of surface can be composed by the medium of gradient of normal line at these points. If the relation between light source and desirable light distribution is assumed, this eqation can be solved by formal or numerical integration.Generally, this solution is different from second-degree surfaces. It is comparatively easy to solve this eqation in the case of a point source and uniform flood lighting. The photographs of a wide flood type sealed-beam lamp designed by this method and its light pattern compared with a medium flood type one are indicated.

Radiation field from a rectangular source

Many radiation shielding problems involve calculations of the response of an isotropic detector to radiation of arbitrary angular distribution from uniform rectangular sources. In calculations of this type the family of integrals integral /sub s/(cos theta dS/r/sup 2/)P/sub 1/(cos theta ) and the integral integral /sub s/ (dS/r/s up 2/)exp(-- mu t/ cos theta ) are frequently encountered, where theta is obliquity with respect to an axis perpendicular to the plane containing the rectangular radiant surface. S, r is the distance from an element source area, dS, to the detector, mu is the attenuation coefficient, and t is the barrier thickness. Solutions of the first type of integral facilitate use of Regendre expansion representations of radiation directional distributions, and may also have application in other radiant surface studies, such as illumination and heat exchange engineering. The second integral relates to exponentially attenuated radiation from a plane isotropic rectangular source sepanated from the detector by a layer of material of thickness t. Formulas, expansions, and numerical results are presented. (autu)

螢光放電燈による人工照明

The author has, ever since 1950, been in the comparative study of fluorescent lamps and incandescent lamps as artificial light-sources by making quantitative and qualitative experiments to prove which is superior from the viewpoint of eye-hygiene and illumination engineering. This time, the author conducted comparative experiments with both types of light-sources in relation to speed of vision with fixed test types, and discernible velocity with moving objects, coming to the following conclusion.A. Fixed Test Types(1) Of all types of light-sources, irrespective of white or colored, time of exposure drastically lessens for the range from 1 H. Lux to 30 H. Lux, and the minimum is reached at about 50 H. Lux. Then gradual decrease in time of exposure continues up until 100 H. Lux. The speed of vision is proportional to logarithm of intensity of illumination.(2) White light is usually superior in speed of vision to any colored light, namely, de luxe daylight fluorescent lamp is best, and then daylight fluorescent lamp and white fluorescent lamp come next slight differences. Then the incandescent lamp, blue-white fluorescent lamp, green fluorescent lamp, and pink fluorescent lamp follow in the order.(3) The rate of the increase in speed of vision to the increase in intensity of illumination is greater in low intensity of illumination, and it grows smaller as intensity of illumnation rises up.B. Moving Object(4) Discernible velocity varies even with the same regularly spaced black and white stripe-patterns in accordance with the angle to face the direction of movement. Discernible velocity is at the minimum in case of the angle of ±45°, and as getting farther off from this angle, it grows the greater.(5) The broader the space is between the black and white stripes, the greater will be the discernible velocity.(6) In case the size of test type remains unchanged, discernible velocity suddenly grows greater until the intensity of illumination on the surface of test type is as large as 3050 H. Lux, and thence up to 500 H. Lux, it continues to increase but gradually. Discernible velocity is proportional. to logarithm of intensity of illumination.(7) In case intensity of illumination is constant, discernible velocity gets heightened, as the test type grows larger in area. A lineal relation is established between the two factors.(8) In case the bright and dark faces of the moving object continue to alternate, the illumination by fluorescent lamps is found inferior to that of incandescent lamps in low intensity of illumination up to 100 H. Lux. In cases other than the above, no significant difference is noticed between the two light-sources, irrespective of moving object or intensity of illumination.

DEVELOPMENT OF FIRE‐RETARDANT DECK COVERING MATERIALS

DEVELOPMENT OF FIRE‐RETARDANT DECK COVERING MATERIALS

Lighting of budd field

The indirect lighting by mercury-vapor lamps of a plant 25 acres in area and nearly 60 feet high is of interest to all illumination engineers. How a lighting system was designed which would meet the requirements from an engineering basis and at the same time be practical from a cost consideration is explained by two engineers who were concerned with the lighting of Budd Field.