If you take apart the LED lights, you will find a tight arrangement of yellow LED lamp beads. But have you ever wondered why the light emitted by these yellow LED lamp beads is white? A few days ago, when a reporter from the China Securities Journal investigated the LED packaging leader Mu Linsen, Tang Guoqing, the company's executive general manager, took the reporter into the workshop and unveiled the mystery.
LED lamp beads
Image source: Mulinsen's official website
"It starts with the principle of LED light." Tang Guoqing told reporters that in 1986, Isamu Akasaki of Nagoya University in Japan and his student Hiroshi Amano successfully made gallium nitride crystals, and found in 1989 that when current is passed into the crystal, the latter's luminous energy is enhanced. This research result was noticed by Shuji Nakamura, an employee of Nichia Chemical Industry, and in 1993, they produced a high-brightness blue LED in the direction of their research. In 2014, Isamu Akasaki, Hiroshi Amano, and Shuji Nakamura were jointly awarded the Nobel Prize in Physics for their "invention of a high-brightness blue light-emitting diode, which brought an energy-saving and bright white light source". And blue light-emitting diodes, i.e., blue LEDs.
Isamu Akasaki, Hiroshi Amano, and Shuji Nakamura Image source: Nobel Prize official website
The invention of blue LEDs has enabled human beings to gather LEDs that can emit three primary colors of light, and have been able to use LEDs to make up enough bright white light. The invention of white LED lamps has greatly improved lighting efficiency, and has been hailed as "the second lighting revolution after Edison".
"But we can't use blue light for daily lighting, so blue LEDs need to be excited by yellow phosphors to show white light." Tang Guoqing pointed to the equipment that was working and told reporters, "The LED lamp beads are coated with yellow phosphor, and then the glue is added to complete the packaging." ”
Tang Guoqing introduced that because red, green and blue are the three primary colors in nature, the superposition of the three colors will produce white, and the superposition of red and green will produce yellow, so the blue LED will naturally emit white light by stimulating the yellow phosphor.
Tang Guoqing, executive general manager of Mulinsen, introduced the principle of LED light to reporters Photo by Ren Mingjie, reporter of this newspaper
In the same way, the combination of blue LED and red and green phosphors can also be used to make white LEDs, and different proportions of red and green phosphors can be adjusted to achieve the desired white color temperature effect; Red, green, and blue LED chips can also be used to mix light, and by controlling the brightness and color ratio of the three LEDs, a relatively pure white light can be obtained, and the effect of adjusting the color temperature can also be realized.
Guohai Securities said that according to the luminescence mechanism, electric light sources can be divided into three categories: thermal radiation light sources (incandescent lamps), gas discharge light sources (fluorescent lamps, high-pressure sodium lamps) and semiconductor light sources (LED lamps). Compared with the first two, semiconductor light sources not only have higher luminous efficiency and display performance, but also have a longer service life, lower unit energy consumption, and are more environmentally friendly, so in recent years, LED lights have gradually replaced traditional light sources. According to market research firm HIS, the share of LED lighting will reach 83.8% in 2025.
China is the world's largest producer and exporter of LEDs. According to customs data, the total export value of mainland lighting products in the first half of the year was about 27.5 billion US dollars. Among them, the export value of LED electric light source products was about 2.3 billion US dollars, accounting for 88% of the total export of electric light sources for general lighting in mainland China, an increase of 1 percentage point year-on-year and 9 percentage points compared with the same period in 2019.
As the enterprise with the highest sales of LED packaging and lighting fixtures in China, MLS was founded in 1997 and landed on the Shenzhen Stock Exchange in 2015, with revenue of 8.182 billion yuan in the first half of this year, a year-on-year decrease of 1.6%; net profit was 262 million yuan, a year-on-year increase of 28.8%; The amount of operating cash flow is 944 million yuan, and the cash dividend is planned to be 534 million yuan.
The company implements a multi-brand strategy and owns domestic brands such as MLS, MLS, Light Source Family, Air Purification Vision, as well as foreign brands such as LEDVANCE and Forest Lighting. In 2017, MLS successfully acquired LEDVANCE, the light source business of global lighting giant OSRAM. LEDVANCE has a long history and obvious channel advantages, especially the overseas LEDVANCE brand business, which has a development history of nearly 100 years and enjoys a high reputation in the world. Since the completion of the acquisition, LEDVANCE's overall performance has been stable, with revenue of 10.606 billion yuan in 2023, accounting for 60.48% of MLS's total revenue.
It is worth mentioning that LEDVANCE and Osram recently renewed the brand cooperation agreement, extending the brand authorization to 2036, expanding the scope of authorization from lighting products to "light sources and luminaires", from domestic to global. In the first half of the year, LEDVANCE continued to strengthen the construction of brand channels and the output of product strength from various aspects such as design, channels, products and operation support, and explored emerging markets. After the renewal, LEDVANCE will maintain diversified and in-depth cooperation with OSRAM to support the development of global markets and new business layouts.