Illuminance Meter Research Articles

照度計相対分光応答度測定の国内比較

照度計相対分光応答度測定の国内比較

温水パネルラジエーターの輻射放熱量に関する測定とその考察

The net thermal radiation of hot water panel was measured in accordance with the new measurement method using the radiant illumination meter, developed by Heating Machinery Society of Japan in 1987. The main results are shown as follows : (1) The ratio of radiation to total output of single panel and double panel are 20〜30% and 11〜14%, respectively, regardless of temperature difference between room air and hot water in panel. (2) the measured values are 0〜20% greater than predicted values of thermal radiation based on Hottel's radiant theorem.

The Detector-Based Candela Scale and Related Photometric Calibration Procedures at NIST

The candela, one of the SI base units, has been realized by using absolutely calibrated detectors rather than sources. A group of eight photometers was constructed using silicon photodiodes, precision apertures, and glass filters for V (λ) match. Their absolute spectral responsivities were calibrated against the NIST absolute spectral responsivity scale. The measurement chain has been significantly shortened compared with the old scale based on a blackbody. This resulted in improving the calibration uncertainty to 0.46% (2σ), a factor-of-2 improvement. This revision has made various photometric calibrations at NIST more versatile and flexible. Luminous intensities of light sources ranging from 10 -3 to 10 4 candelas are directly calibrated with the standard photometers, which have a linear response over that range. Illuminance meters are calibrated directly against the standard photometers. A luminance scale has also been realized on the detector base using an integrating sphere source. Total flux ranging from 10 -2 to 10 5 lumens can be measured in a 2 m integrating sphere using a photometer with a wide dynamic range. The revisions of the calibration procedures significantly improved the calibration uncertainty.

Development of Photo Sensor Using Magnetic Semiconductor

This paper describes the preparation and response to light stimulation of a magnetic semiconductor photosensor (MSP). The MSP is composed of ferrite powder, binder, solvent and a radiant flux absorbent. After the mixed magnetic semiconductor fluid is printed using a spray gun, it is sintered at 800C and its surface is covered with radiant flux absorbent. When light in the visible wavelength range is incident on the MSP, the radiant flux absorbent absorbs the radiant energy and the element temperature rises. As a result the MSP reluctance increases, so that an optical stimulus is manifested as a change in magnetic behavior, that is read out by a Hall element. MSPs can be used in photo relays, illuminance meters and photocouplers.

磁性半導体を用いた光センサの開発

This paper describes the preparation and response to light stimulation of a magnetic semiconductor photosensor (MSP). The MSP is composed of ferrite powder, binder, solvent and a radiant flux absorbent. After the mixed magnetic semiconductor fluid is printed using a spray gun, it is sintered at 800C and its surface is covered with radiant flux absorbent. When light in the visible wavelength range is incident on the MSP, the radiant flux absorbent absorbs the radiant energy and the element temperature rises. As a result the MSP reluctance increases, so that an optical stimulus is manifested as a change in magnetic behavior, that is read out by a Hall element. MSPs can be used in photo relays, illuminance meters and photocouplers.

Light source with light emitting diodes. Determination of limited frequencies and of the crest factor of illuminance meters and luminance meters

The checking of illuminance meters and luminance meters, following the recommendations issued by the International Commission of Illumination as to their frequency effects and their crest factor requires the use of a modulated luminous beam. A light source with light emitting diodes is suggested to carry out this check. It emits light sinusoidally modulated (frequency: from 10 Hz to 32 kHz) or in pulses of variable width (frequency: 100 Hz; duty cycle: 1/16 to 16/16) modulated in a constant average luminous flux, thanks to an electronic supply with logging control.

An Extinction-Type Photometering Technique for Low-Light-Level Luminance Measurements in Accident Investigations

Abstract An extinction-type luminance measurement method using an inexpensive illuminance meter for low-light-level measurements is described. The method has application in night-time crime and accident scene investigations where poor and inadequate visibility may be a contributing factor. The meter is useful for measuring luminances under field conditions.

半円筒面照度の妥当性と照度計の試作

半円筒面照度の妥当性と照度計の試作

Photometric error due to non-uniform responsivity in a photometer aperture

Photometric error due to non-uniform responsivity in a photometer aperture is theoretically analyzed for illuminance measurement. Such error is only caused when neither responsivity nor illuminance is distributed uniformly in the aperture of an illumination meter. This error is given by the product of the fractional-standard-deviations in both distributions and the correlation coefficient between them. The fractional-standard-deviation is consequently proposed as a parameter to describe the non-uniformity of each distribution. This theory is validated by applying it to error estimation for luminance measurement of a color TV picture tube using a luminance meter composed of a diaphragm, a tube and an illumination meter. The spacial resolutions required in the measurements of both distributions, which make it possible to precisely estimate the above error, are also discussed. It is revealed that, if the distribution of either responsivity or illuminance is more gradual than the other and sinusoidal, the resolutions should be less than 1/8 the spacial period in which the sinusoidal patterns are repeated.

受光器の感度不均一性による測光誤差

Photometric error due to non-uniform responsivity at the surface of a detector is theoretically analyzed for illuminance measurement and for light beam flux measurement by means of an illuminance meter. In illuminance measurement, photometric error is caused only when responsivity and illuminance are not distributed uniformly in the aperture of the illuminance meter. This error is given by the product of the relative standard deviations of both distributions and their correlation factor. As a result, the relative standard deviation is proposed as the parameter to describe the non-uniformity of each distribution. The spatial resolutions reequired to measure both distributions, which would make it possible to precisely estimate the above error, are also discussed. The conclusion is reached that, if the distribution of either responsivity or illuminance is more gradual than the other and sinusoidal, the resolution should be smaller than 1/8 the spatial period in which the sinusoilal patterns are repeated.

IES Transaction: An Instrument for the Measurement of Equivalent Sphere Illumination

A new instrument is described for the measurement of equivalent sphere illumination. A basic optical system formed by the visual target and telephotometer is usually used for luminance contrast measurements. It is shown that this optical system can be replaced by an ordinary illuminance meter, the angular response of which is changed to mimic that of the bidirectional reflectances of a visual target's background and task. Moreover, a technique is described for producing a set of variable transmittance enclosures that are placed over an illuminance meter to give it the appropriate angular response. A combination of computer plotting and photographic techniques is used to generate enclosures that have transmittances which vary in the appropriate fashion. Successful operation of the new device is demonstrated.

Effect of Light and Other Factors on Capsule Expansion in Funaria hygrometrica

Effect of Light and Other Factors on Capsule Expansion in Funaria hygrometrica

A new portable photoelectric illumination meter

This paper describes a photoelectric illumination meter using the emission type of photocell with valve amplification. Simplifications are introduced in the electrical circuit with a view to simplicity and compactness. The instrument is capable of measuring illuminations as low as 0.005 f.c. to an accuracy of ± 1 per cent.

Résumé of Methods of Determining Screen Brightness and Reflectance<!--<xref ref-type="other" rid="fn1-10.5594_J08683">*</xref>-->

The importance of screen brightness as compared to auditorium brightness is referred to. Various methods of measuring and determining the brightness and reflectance of screens are reviewed. A new photoelectric illumination meter is described which should simplify the procedure of making screen measurements.