China National Institute of metrology for LED products, such as the calculation of the value of the relevant national standards

Topic: LED standards and traceability

Expert: Director Liu Hui China Institute of Metrology optical and Laser Institute of metrology room

Beijing Olympic Games opening ceremony of the historical picture and the dream ring left a deep impression. However, not many people know that the director of this scene of the hero, but it is called a LED (light-emitting diode) products.

"The 2008 Olympic Games in Beijing, LED lighting investment of about 500 million yuan, a large number of applications that LED lighting technology in the electronics and lighting industry prospects are very broad. Liu Hui, deputy researcher of China Academy of metrology. Liu Hui Institute of Optics and laser metrology science laboratory, is currently developing LED product value measurement and related national standards.

In 1960s, the first application of semiconductor PN has made the advent of the LED light source principle. Because of its low light efficiency, it can only be used as an indicator lamp on electrical equipment and instruments. After more than 30 years of development, LED light rich. At the beginning of 90s, the successful development of the red and yellow light greenish blue, GaAlInP and GaInN two kinds of new materials, the LED gradually entered the fields of display and lighting. At present, LED is widely used in traffic signals, outdoor night lighting, interior decoration and functional lighting, LED display has become the standard configuration of public facilities. With the development of technology and the development of new white LED, the development and application of LED are more and more popular.

China is a big country in the production and use of LED products, in 2007 China's LED Application Market Sales Revenue $4 billion 200 million, composite packaging production accounted for 15% of the world. With the rapid development of LED industry, it is necessary to accurately measure the light, color, electricity and thermal parameters of LED in order to control the quality of the products and sell the products. Many enterprises of our country has gradually developed to LED chip, luminous materials, LED tube, LED lamp and other industry chain, detection equipment, downstream of each link, including the quality inspection laboratory for testing equipment, production line automatic detection and sorting equipment and products with instruments.

However, due to the constraints of the level of some of the equipment manufacturing technology, as well as the understanding of the gap between the LED measurement standards, making the measurement results between the various manufacturers often have obvious differences. For the same LED pipe, the measurement results between two manufacturers may be more than 10 percent or even dozens of errors, far more than the general range of photometric accuracy.

Liu Hui introduction, the current value of LED measurement instruments traceability method is not uniform, only because of the uncertainty caused by the instrument calibration is much higher than other photometric instruments. Therefore, it is urgent to establish the LED standard and traceability system. Although the light and color parameters of LED can be traced back to the established standard of measurement, LED has its own characteristics, and can not be completely according to the test method of incandescent lamp.

The present study Chinese optics and Laser Technology Research Institute of Metrology in the ongoing research work in this area, by using the actual data with customers or close to the LED as the transfer standard, which can improve the consistency of measurement results, reduce the requirements for measuring the quality of personnel and requirements. Accurate and consistent measurement results are the premise and guarantee for the healthy development of the industry, standardize the market order and fair competition.

Calibration and quantity to establish standards for special LED light and color parameter measurement will be unified LED photometric and colorimetric, radiation and electrical parameter value transfer method, the LED of our country production, application and export will play a promoting role. On the one hand, can promote China's LED to improve the quality of the product, the value transfer situation is not consistent to play a regulatory role; on the one hand, with the development of economic globalization, the measured data of the mutual recognition of the increasing demand, the foundation depends on the benchmark level and consistency.

To this end, the International Bureau of Metrology (BIPM) according to the requirements of WTO, National Metrology Institute invited by discussion on 1999 signed the "agreement on mutual recognition of national measurement standards and the National Metrology Institute issued for calibration and measurement certificates" (MRA), put forward the mutual recognition of calibration and measurement certificates for measurement datum and National Measurement Institute issued by countries the. The international organization for Standardization (ISO) international standard assessment laboratory capacity revised (ISO17025-2000) has been clearly defined, must have traceability for all measurement data of all kinds of laboratories, which can be traced to the national benchmark.

On behalf of Chinese Institute of metrology Chinese in 1997~1998 by the International Committee of the Advisory Committee radiation luminosity measurement (CCPR) International Comparison of luminous intensity unit organization, a total of 16 countries participated, results show that the strength of our units and international light average phase difference of 0.16%, at the international advanced level. At the same time, China also participated in the international comparison of photometer responsivity, the participating countries have a total of 15, of which 4 countries value is less than or equal to 0.2% and the average deviation of China was 0.2%. These data indicated that the strength of our international light unit and the average value is consistent with.

At present, China's all photometric projects have entered the international calibration and mutual recognition database CMC, that is, in these projects we issued a certificate of international mutual recognition, without repeated testing.