Japanese white LED measurement standards detailed analysis
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Baked with white LED Standard LED technology advances, many people have been full of potential as a new generation of the main light source, however, has the traditional lighting LED light emitting characteristics of different space, so that the original optical properties suitable for measurement of traditional light sources approach may not be suitable for LED, such as the luminous flux (LuminousFlux), light intensity and chromameasurement, or LED's precision and accuracy are measured will become the problem. Therefore, the world's leading Standards Association are amended or new LED measurement standards, but a wide range of LED package, the performance is also different, so there are associations for different uses LED to develop new measurement standards to the International Commission on Illumination for example, in 2007, substantially revised its original LED measurement of technical documents CIE-127, but a lot of controversy, there are still many problems to be resolved measurements, and by the U.S. Department of Energy led by the , and its solid-state lighting products with the promotion process, by the American National Standards Institute Illuminating Engineering Society of North America standards group formed, being solid-state lighting standards related to the formulation of the test, including the optical rotation measurements, Measure color and life assessment of such standards, but the characteristics of these standards in its content of solid-state lighting is to be evaluated as a whole, that is, LED monomer can not by the norms of these standards for measurement.
In recent years, China also committed to promoting standards of semiconductor devices, the government's support, has launched a testing method of semiconductor light emitting devices, and other relevant standards are being considered.
However, white LED lighting standards in the promotion, the most advanced countries are Japan, which Japan Illuminating Engineering Society , Japan's Commission on Illumination, Lighting Industry of Japan and the power ball Industries Association of Japan in 2004, four groups have been set a common standard "method of lighting with white LED metering General", as the only white LED for lighting measurement standard set, when its first edition has not been the lead in formulating a number of norms off projects, such as the manufacture of standard LED, small light intensity measurement modules and life assessment methods.
LED light of progress of measurement standards for content and there is still room for expansion, four groups published in the March 2006 revision of this standard to increase the standards and revise the original content, chromaticity and luminous flux measurement measurement methods to make more detailed specifications. However, based on a cautious attitude, there are still many parts are placed in the subsidiary part of some, but not the actual standard, but the instructions in the relevant specifications are still very detailed, can be found at this stage of the LED standard international literature, this standard can be said that the contents of the most complete specifications. In the current industry is still a common lack of adequate case LED measurement specifications, the standard will be a very important reference. The following highlights key provisions of this standard, as well as the additional part of the revision.
Limit the application of white LED lighting at the beginning of the standard title, and already declared is limited to lighting for white LED, it is limited to that goal will be measured using white light LED, to limit the LED compared with the standard method of measurement effectively enhance the accuracy and content of the standard LED to make a very detailed provisions. Measurement of light intensity in part, in accordance with the provisions of the International Commission on Illumination's standard conditions of the measurements; part in the flux measurements, it will be using the integrating sphere measurements, and an increase in the revised version of the color, correlated color temperature, color rendering index and other measurement methods, and in principle the use of an integrating sphere as its school system, the incident light.
This standard is mainly developed specifications for the single LED, but the LED modules for a small measure of light intensity is also included specifications for a small LED modules, its not necessarily apply under the CIE standard conditions, the average LED light intensity measurement method.
White LED lighting standards and defined the standards of other LED's the biggest difference in the "white lighting LED" make a very clear definition. According to the interpretation of this standard, the so-called "white lighting LED" The measurement of the average light intensity of luminous flux or light color, should meet the spectrum , covering almost the full range of visible light region, and which can not have missing parts; correlated color temperature of range (2500 | 10000) K or less; and the correlated color temperature in the CIE1960 uniform color coordinates, with the Planck trajectory (PlanckianLocus) of the deviation three conditions must be less than 0.02.
It should be noted that in this definition, RGB tri-color LED lighting will be excluded from the scope of white LED, in fact, the interpretation of the annex to this standard, the white LED lighting is a controversial definition of the project , the provisions of the correlated color temperature, due here for the general lighting, so the start is the same level with the fluorescent light (correlated color temperature for the (2700 | 8000) K or so) to consider, however, its reference to the actual development of the current white light LED technology, it will set correlated color temperature range from (2500 | 10000) K range.
Light intensity / luminous flux measured in two ways because there is no large number of standardized and unified LED package shape, size and lighting features, but have different purposes in accordance with the design of various structures, it is difficult to measure LED. Therefore, standard LED should have the structure, performance, reproducibility must be provided for.
In this standard, a standard LED light intensity is divided into two kinds of measurements and flux measurements, based on measured characteristics of its different for different design concepts. For example, a standard measurement of light intensity LED, the light intensity measurement as methods, the tested LED Mechanical aligned metering device (PhotoDetector) is a correction factor is important, so the standard mechanical axis alignment is easy with bullet-type (Lamp) package as a standard form; The flux measurement standard LED, taking into consideration the provisions of all flux measurements, the use prevents the rear towards the LED emit light, and more uniform light intensity metal pot package as a standard form. It is worth noting here two forms of the standard LED, are using indium gallium nitride chip series with yttrium aluminum garnet (YAG) phosphor made of white LED, the corresponding item in the definition white LED for lighting described in part without the lack of wavelength.
Since the standard LED is an important reference measurement, so the standard hope to minimize the influence of the surrounding environment, the optical and electrical properties of the instability to a minimum, to achieve the desired reproducibility requirements. In addition to the standard measurement of the ambient temperature changes limit must be less than 2 ℃, for the reduction of the initial LED changes, the proposal should have been more than 100 hours use of constant current (eg 20 mA) drive standard LED, standard LED of the ambient temperature shall be control in 25 ℃. In the revised edition, the increase in temperature in Annex 4 slot (Socket) (as a function of chip temperature control lighting fixture) stated their requirements in the case of constant current, LED time to reach thermal equilibrium (I hope at least 5 minutes) after the lighting measurements. |
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Author Resource:-
I am a editor, http://www.chinaqualitylighting.com provides foam body pillow,electric shredder chipper, welcome to visit!
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By :
Jessie Stone
Submitted
2010-10-10 17:34:06 |
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