In the case of improved yellow light efficiency, the traditional LED + phosphor lighting method will gradually be replaced. The era of pure LED lighting is coming.
Traditionally, the LED+phosphorescent illumination method has its limitations. Since the luminous efficiency of the yellow LED is low for a long time, the blue light emission efficiency is very high, and the highest luminous efficiency of the blue LED is currently about 80%. Therefore, in the previous LED lighting solutions, a large number of blue LEDs and phosphors were used to generate white light illumination. However, experiments have shown that long-term blue-rich illumination is harmful to human physiology.
Traditionally, the luminous efficiency of yellow LEDs is very low. In 1965, Bell Labs initially studied yellow LEDs. In 1971, Monsanto achieved one-tenth of the luminous power efficiency. After continuous development and technological innovation, Toshiba reported a yellow LED with a luminous power efficiency of 9.4%. No new progress has been made since.
Under this circumstance, China's R&D team made an important breakthrough in 2016, achieving 20% luminous power efficiency. The latest progress has been achieved by 26.8%, which is about three times the level of foreign research, reaching 160-230lm/W@20-2A/cm2. At present, GaN/Si-based yellow light exceeds other routes of yellow light! Such luminous efficiency can already be illuminated like a light source without the use of a phosphor.
The reason for achieving such a technological breakthrough is to master the entire technology chain on the one hand and to master the entire middle, lower and lower reaches. On the other hand, it is to combine equipment and craftsmanship. If you just buy ready-made equipment and only stay in the stage of using imported equipment, it is very difficult to break through the yellow light. Mastering the core technology of autonomous equipment and the silicon substrate, and combining the two, can achieve a key breakthrough in the yellow LED.
The advantages of pure LED lighting include taking into account the index and efficiency, solving the problem of rich blue light hazard, meeting the low color temperature demand, saving rare earth resources, solving the problem of color drift and light decay, breaking the efficiency limit, realizing intelligent scene lighting, and taking into account visible light communication technology. A healthy light source should protect the eyes and maintain normal biological rhythms. It is in line with the long-term cultivation of the habit of "sunrise and sunset".
Finally, the visible light LED light effect has room for further improvement. The operators engaged in LED and LED lighting in China should have greater ideals.
