Solid state lighting (SSL) beyond the traditional lighting rely on?

Daily consumption in Kunming at the end of 2012 senior lighting designer forum, I made a report "to discuss" the four elements of green lighting, green lighting which must include energy saving and environmental protection, safety and comfort of the four elements. With the progress of the light source technology and the improvement of the standard, the safety and comfort of the light can also be discussed in depth.

Solid state lighting includes LED and OLED. At present, OLED has not been widely used in general lighting, so this paper mainly discusses the LED. With the elimination of incandescent lamp and high pressure mercury lamp gradually withdraw, the scope of traditional lighting is narrow, the current mainly includes halogen tungsten lamp, fluorescent lamp, high pressure sodium lamp and metal halide lamps and other light source and its supporting appliances and lamps.

Evaluation of energy efficiency indicators light source and lamp light efficiency, life and light flux maintenance rate. The environmental protection index is the discharge of harmful substances in the process of production, transportation, operation, waste and recycling, as well as the corresponding emissions of electricity consumed during the operation. LED does not contain mercury and other harmful substances, and the luminous efficiency, life and luminous flux maintenance rate are more than the traditional light source, so the advantages of energy saving and environmental protection has been recognized by everyone.

For safety, all light sources and luminaires shall comply with the mandatory standards for electrical safety. Here we only discuss the problem of the blue light hazard. Comfort index has color temperature, color rendering index, color tolerance and glare index. Traditional light source for a long time, equivalent to the biological safety and quality of light set the threshold. LED has been fully beyond the traditional lighting it?

Blue light hazard

Blue light hazards have international standards and national standards, hazard levels and test methods have been standardized. A number of research results have been published in the white paper of the journal, conference and semiconductor lighting alliance.

According to the theoretical and experimental studies conducted in 2013, we find that the blue light hazard is related to the color temperature and brightness of the light source, and the LED is not essentially different from the traditional light source. In the light of the color temperature and color rendering index are similar, almost all kinds of light source efficiency of blue light hazards; blue light hazards and color temperature is proportional to the efficiency, so the efficiency of 6500 K light blue light hazard is 2.4 times 2700 K light source, influence is not big.

The evaluation of the blue light intensity is proportional to the brightness of the blue light, while the brightness range of the light source can reach 100 times. Control the brightness of the light source, the blue light hazards also control. For the color temperature below 6500 K light source, as long as its brightness is not more than 100kcdm-2, or the illumination is not more than 1000 LX, is the safety of blue light (Class 0, no danger). The higher brightness of the light source, if classified in the low risk category (1 categories), as long as the avoidance of direct viewing, the use of light sources are not limited.

The traditional indoor lighting light source, fluorescent lamp and compact fluorescent lamps (CFLs) the minimum brightness, in general lighting color temperature range belong to the 0 blue light hazard (no danger), which belongs to the light source can be a long time to open; tungsten halogen lamp and metal halide lamp with high brightness, only a short time look. High power LED single or integrated packaging device brightness is high, may reach the quartz halogen lamp brightness, such as for the light, can not directly with the eyes. Regional lighting with LED light source or lamp, the need to add a diffuser or diffusion cover outside the package, to reduce the brightness of an order of magnitude or more, it can also achieve 0 types of blue light hazards. If the brightness of a LED light source is almost the same as an energy-saving lamp, then it must be a blue light.

Of course, due to the brightness of the LED light source and lighting should be larger, do lighting design should pay special attention to control glare. Overall, the general lighting with white LED light source and lighting as long as the control of brightness, the blue light hazards in the safe range.

Non visual biological effects have not been clearly defined. The domestic and international research results show that the rhythm efficiency of the light source is directly proportional to the color temperature. In order to adapt to the natural rhythm of the human body, indoor lighting at night should use low color temperature light source, so as not to interfere with the body's sleep.

Two, light quality

Comfort is determined by the light quality of the light source, including spectrum, color temperature, color rendering index, color tolerance, spatial color uniformity, glare index, strobe and color stability during life.

Over millions of years of evolution, the human eye has adapted to the continuous spectrum of nature, including the sun, the sky and the moon. Early artificial light sources are continuous spectrum, such as fire, candles and oil lamps, as well as the first generation of electric light source incandescent lamp and halogen tungsten lamp. With the gas discharge light source, high light efficiency of the fluorescent lamp spectra and different degrees of continuous high pressure sodium lamp and metal halide lamp appeared in people's life, but the use of less than 80 years is only a moment in human history, is not enough to affect the human eye vision from a genetic perspective. From the nature point of view, the continuous spectrum light source is always more natural choice in interior lighting.

At present, the mainstream of the LED is to use the blue chip to stimulate the yellow phosphor to produce white light, which belongs to the continuous spectrum in the visible region, but the green area is weak, and the red light area is less. Therefore, the spectral continuity of LED is stronger than that of fluorescent lamp, but no more than the ceramic metal halide lamp. General LED red special display index (R9) requires only >0, can not be good to restore the deep red. So the Great Hall of the people with LED do lighting transformation, or red with the halogen tungsten lamp to shine