Construction of Two-Axis Goniophotometer for Measurement of Spatial Distribution of a Light Source and Calculation of Luminous Flux

The solid volumetric true−3D display requires light source with high brightness, high energy utilization rate and high frequency color field. So high−power red, green and blue LEDs with collimators were used as the projection light source. Firstly, the required quantity of LEDs was determined according to the required output luminance, the efficiency of the projector and the red, green and blue LEDs' parameters. Secondly, with the consideration of the LEDs' dimensions, light−emitting mode and output luminous flux, collimator was designed and simulation model was established. Simulation and practical measurement results both show that light source based on high−power LED meet the requirements of the solid volumetric true−3D display.

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Comparison of luminous intensity distributions

Lighting Research and Technology ◽

10.1177/1477153515614613 ◽

2016 ◽

Vol 49 (1) ◽

pp. 62-83 ◽

Cited By ~ 2

Author(s):

F Gassmann ◽

U Krueger ◽

T Bergen ◽

F Schmidt

Keyword(s):

Structural Properties ◽

Light Source ◽

Radiation Characteristic ◽

Luminous Flux ◽

Luminous Intensity ◽

Measuring System ◽

Operating Parameters ◽

Data Noise ◽

Flux Data ◽

The Difference

Luminous intensity distributions enable an evaluation of the spatial radiation characteristic of a light source. This radiation characteristic is determined by the structural properties of the light source, its operating parameters and the properties of the measuring system. This paper describes some possible methods and rules for comparing luminous intensity distributions. The focus is on the development of calculation rules for quantifying the differences between two luminous intensity distributions. The difference measures developed allow the user to establish an objective comparison between luminous intensity distributions, this comparison being completely independent of the measuring system, the properties of the luminous intensity distributions and the users themselves. Further, the dependence of the properties of luminous intensity distributions resulting from measurement practice, such as adjustment uncertainties, regions that cannot be covered or measured, deviations of the total luminous flux, data noise and resolution differences, are discussed, and appropriate pre-processing and correction steps proposed. In addition, various visualisations of the differences between two luminous intensity distributions are demonstrated and the functionality of the difference measures developed is documented.

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Missile-borne measuring device of effective light intensity spatial distribution for pulsed light source

Journal of Applied Optics ◽

10.5768/jao202041.0410001 ◽

2020 ◽

Vol 41 (4) ◽

pp. 754-760

Author(s):

YUAN Liang ◽

◽

QIU Lirong ◽

KANG Dengkui ◽

LI Hongguang ◽

...

Keyword(s):

Spatial Distribution ◽

Light Intensity ◽

Light Source ◽

Pulsed Light ◽

Measuring Device

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Development of portable device for measurement of dynamic and static light-emission WOLED characteristics

Technology audit and production reserves ◽

10.15587/2706-5448.2021.225239 ◽

2021 ◽

Vol 1 (1(57)) ◽

pp. 30-33

Author(s):

Ihor Helzhynsky ◽

Stepan Kutsiy ◽

Andriy Veryha ◽

Khrystyna Ivaniuk ◽

Taras Dudok

Keyword(s):

Light Source ◽

Data Exchange ◽

Light Emission ◽

Spectral Characteristics ◽

Light Flux ◽

Luminous Flux ◽

Visible Range ◽

Light Sources ◽

Measuring Device ◽

Routine Work

The research object of this work is the parameters of organic light-emitting diodes, namely power and luminous flux. Determination of these parameters can be carried out using a photodiode and requires measuring the dark current of the sensor (photodiode), measuring the current of the photodiode when illuminated by the LED under investigation. And also take into account the relationship between the light flux received by the sensor and its output current, and take into account the spectral characteristics of the sensor. Calculate the investigated parameters of the LED based on the measurements. Carrying out these measurements requires laboratory instruments and workplace organization, and further calculations are routine work. It is possible to increase the measurement accuracy by improving the existing methods for measuring the required parameters, and it is possible to automate the process of measurements and calculations using a modern microprocessor radioelement base. Microcontrollers are widespread such radioelements. They have the necessary peripherals for independent operation and have sufficient computing power to implement the required measuring device. Its application makes it possible to automate the measurement process, carry out the necessary calculations, save correction constants, accumulate and process the obtained data, analyze these received data, exchange data with a computer, etc. So, the work is aimed at developing a methodology that will allow the simultaneous measurement of power and luminous flux of planar light sources. And also on the feasibility of this technique in the device and software with the ability to measure the power of the light source in an arbitrary band of the spectral visible range. Thus, it is possible to determine what power in watts a light source emits with the dynamics of supply currents in the optical bands, knowing the spectrum of this source without using glass filters. So, the result of applying the technique is to determine the power of light radiation (in watts) or the luminous flux (in lumens) of the emitter (light sources).

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THE USE OF A MIX-450 MOBILE FORENSIC LIGHT SOURCE TO IDENTIFY CRIME TRACES

Russian investigator ◽

10.18572/1812-3783-2020-12-3-5 ◽

2020 ◽

Vol 12 ◽

pp. 3-5

Author(s):

Olga A. Barinova ◽

Keyword(s):

Light Source ◽

Human Skin ◽

Luminous Flux ◽

Biological Origin ◽

Forensic Light Source ◽

Fluorescent Lamps ◽

Preliminary Examination ◽

Forensic Tools ◽

Material Evidence

One of the tasks of forensic science is to improve the tactics of conducting an inspection of the scene, which is largely associated with the use of modern technical and forensic tools used to detect, fix and seize traces and other material evidence in order to disclose and investigate a crime and establish the identity of the offender. However, as practice shows, the use of traditional technical means — portable sources of ultraviolet radiation to detect traces of biological origin (blood, semen, saliva and other human secretions) is not always effective. This is due to the fact that the intensity of the luminous flux of fluorescent lamps is quite low, which prevents the detection of traces during daylight hours. In addition, long-term illumination of the object, over 5 seconds, causes the destruction of the DNA in the blood and semen, which prevents the possibility of its further examination. At the same time, the arsenal of methods and technical means is constantly expanding. For example, a mobile forensic light source “MIKS-450” has now been developed. However, there is no information about the types of traces detected with its use. To fill this gap, the author of the article carried out a set of experiments, the results of which testify to the effectiveness of its use for detecting traces of human skin and preliminary examination of documents at the scene. The author also comes to the conclusion that the possibility of detecting traces of human skin depends on the physical properties of the trace substance (dirty or clean hands, dry or wet), the structure of the trace-sensing surface (smooth, rough), its color, as well as the time elapsed since the occurrence traces.

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Influence of a Light Source Installed in a Luminaire of Opal Sphere Type on the Effect of Light Pollution

Energies ◽

10.3390/en13020306 ◽

2020 ◽

Vol 13 (2) ◽

pp. 306 ◽

Cited By ~ 3

Author(s):

Przemyslaw Tabaka ◽

Pawel Rozga

Keyword(s):

Light Source ◽

Spectral Distribution ◽

Spectral Characteristics ◽

Measurement Data ◽

Luminous Flux ◽

Light Pollution ◽

Light Sources ◽

Pollution Effect ◽

The Impact ◽

Effect Of Light

The article presents the results of the studies concerning the influence of a light source installed in luminaire of opal sphere type on the light pollution effect of the night sky. It is known from literature reports that the effect of light pollution is influenced by the spectral distribution of light. Although the influence of the spectral distribution has been widely studied from different perspectives, there is still a need to study this phenomenon—for example, from the point of view of the spectral reflection properties of the ground, on which the lanterns are installed. Hence, the above-mentioned aspect was considered in the authors’ investigations. The luminaire considered has been equipped with 20 different light sources, including the latest generation of lamps (light-emitting diodes, LEDs) as well as the conventional ones. With respect to these light sources, the measurements of light distribution and spectral distribution of emitted radiation of the luminaire were performed. Having these measurement data, the simulations were carried out using the DIALux software, and the calculations were made using the specially prepared calculation tool. On the basis of the results obtained in this way this was stated that the type of light source installed in the luminaire has a significant effect on the sky glow. An important factor affecting light pollution is not only the value of the luminous flux emitted upward but also the spectral characteristics of the emitted radiation, the impact of which is most noticeable. The conclusions from the studies indicate the next steps in the analysis of the light pollution effect. These steps will be focused on extended analysis of LEDs as modern and developed light sources.

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Research on adjustable correlated color temperature COB-LED light source based on flip chips and screen printing technology

10.21203/rs.3.rs-232002/v1 ◽

2021 ◽

Author(s):

Rongrong Zhang ◽

Zuojie Wen ◽

Bingqian Li ◽

Shenghua Liang ◽

Mingde Yang ◽

...

Keyword(s):

Light Source ◽

White Light ◽

Screen Printing ◽

Light Emitting Diode ◽

Luminous Flux ◽

Color Temperature ◽

Current Ratio ◽

Led Light ◽

Driving Current ◽

Screen Printing Technology

Abstract Using the characteristic of flip light emitting diode (LED) chips without front-side welding wires, before applying fluorescent glue throughout the luminous surface, a part of the chips are directionally and quantitatively coated fluorescent glue by screen printing process, a chip on board (COB) white LED light source is developed with adjustable correlated color temperature (CCT). A part of the blue LED chips in the light source excites the fluorescent glue to produce a warm white light (CCT = 2631K), and the other part produces cool white light (CCT = 6181K). When changing the driving current ratio of the two parts of the chips, the CCT of COB LED light source can be continuously adjusted between warm and cool white light. According to the measured data, the relationship between the CCT and the driving current ratio of the two parts is obtained by fitting. Within the adjustable range of the CCT (2631 K to 6181 K), the color rendering index (CRI) is about 90. The minimum is 89.3 and the maximum is 93.1. While achieving adjustable CCT and high CRI, the LED light source has a luminous flux of 1938.76 lm on a circular surface with a diameter of 11 mm. The overall luminous efficiency is close to 100 lm/W.

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MODELLING OF VERTICAL SURFACES RADIATION IN CONNECTION WITH THE EVALUATION OF THE OBTRUSIVE LIGHT

10.25039/x48.2021.po64 ◽

2021 ◽

Author(s):

P. Becak ◽

T. Novak

Keyword(s):

Light Source ◽

Distribution Curve ◽

Field Measurements ◽

Active Surface ◽

Vertical Surface ◽

Luminous Flux ◽

Real Field ◽

Light Sources ◽

The Real ◽

The Creation

The issue of the luminous flux radiation to the upper hemisphere is very broad and complex. The paper deals with the modelling of the vertical surface radiators. It presents an approach to unify the behaviour of these types of light sources. These will be understood as cosine radiators. If this cosine distribution curve is taken into account, then only the luminance and the light-active surface can be known to supplement the information about the radiation of such the light source. The luminance and radiated surface can be obtained relatively easily from real field measurements. The article presents the implementation of this data into lighting calculations and the creation of the distribution curves which are necessary for the radiation calculations of these surfaces. It also analyses the influence of the luminance and active areas on the radiated luminous flux and assign these values to the real radiators.

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