The wavelength of blue light is located in the 400~500nm band, and one of the most important characteristics of light in this band is that it is easily absorbed by highly antimetallic materials such as copper. The absorption rate of blue light by highly reflective metals such as copper is 5-10 times higher than that of common infrared lasers. This characteristic, which enables higher quality and processing efficiency for highly reflective metals, has led to a sharp increase in market demand for blue light lasers.
Key drivers behind the growth in demand for blue light
Undoubtedly, the biggest driving force behind the growth of blue light demand comes from the field of lithium battery manufacturing.
Under the general trend of energy saving, environmental protection and sustainable development, new energy vehicles, mainly electric vehicles, are gradually replacing fuel vehicles. New energy vehicles are already an unstoppable new force in the market.2023 data from the Ministry of Industry and Information Technology at the beginning of the year showed that China's new energy vehicles continued to grow explosively in 2022, remaining the world's number one for eight consecutive years, and the market penetration rate hit a new record high. Earlier this year in July, the 20 millionth new energy vehicle produced in China has come off the production line in Guangzhou! China is expected to be the first country in the world to cross the line into the era of 10 million annual sales of new energy vehicles.
Continued growth in the production and sales of electric vehicles, driven by the rapid growth of the lithium battery market. China's power battery industry continues to lead the world, 70% of the power battery is made in China.
In the manufacture of lithium batteries, many links are involved in the welding of copper, aluminum and other high anti-metal materials, such as pole lug welding, square battery shell welding; which is most commonly used in square batteries, is the use of laser welding parts of the most types of batteries. Compared with the common infrared light, blue light welding can achieve no spatter, no porosity, weld consistency of good welding results, which makes the market demand for blue light is unprecedented.
In addition to the huge driving force of industrial applications, blue light lasers can also be used in medical treatment, underwater detection, lighting, display and other fields, and the demand revealed in these fields has also promoted the development of blue light laser technology to a certain extent.
The core technology of blue laser
The core technology of blue light laser is the blue light single tube chip.
Blue light semiconductor chips are usually based on materials such as InGaN/AlGaN/GaN, etc., and formed into usable single-tube products after epitaxial growth, wafer flow process, cavity surface treatment, packaging and other processes.
Currently, the power level of commercially available blue light single tubes is 5W, with the ability to achieve approximately 10W in the laboratory. There are not many manufacturers that can provide blue light single-tube chips, although there are some domestic manufacturers specializing in this field, but currently in a dominant position is still a few German and Japanese companies, Germany ams OSRAM is one of them.
In 2023 Munich Shanghai Optical Expo, Laser World Magazine had the honor to interview Ms. Jie Xia, senior manager of ams OSRAM system solution engineering department. She said, at present, ams OSRAM has a complete production line from laser chip manufacturing to packaging, and the highest output power of the commercial blue light single tube provided at present is 5W. ams OSRAM has exquisite process capability to produce blue light single tube products with stable performance, which is one of the core advantages of ams OSRAM that can dominate the field of blue light laser chips.
Blue light applications continue to expand
Talking about the application of blue light, Xia Jie said, blue light single-tube 5W power level is not enough to meet the demand for higher power for industrial processing, so more single-tube products will be combined together, after optical beam combining and other processing, in order to achieve higher power can be used for industrial processing of blue light source.
Looking at the semiconductor industry, the complexity is very high, which is very similar to the challenges faced by the photonics industry. Much like the photonics industry, the semiconductor industry continues to invest heavily in research and development. In fact, in 2021, the semiconductor industry is spending a whopping $71 billion on R&D, which ranks second in the world in terms of R&D spending across all industries.
In this exhibition, ams OSRAM demonstrated the module samples of 30W, 100W blue laser based on the blue laser chip assembly, it namely is the combination of multiple single tube chips, through the fiber coupling output, to achieve ≥ 30W, 100W power output, and achieve high brightness and high power density, which can be used for precision processing tasks.
Blue light, as a light source for certain minimally invasive surgeries, will pioneer new innovations in terms of surgical trauma, scar reduction and patient pain. It is reported that a number of organizations are already conducting in-depth research and studies on blue light medical applications, with ams OSRAM providing them with blue light sources.
It is reported that in November 2011, the First Affiliated Hospital of Xi'an Jiaotong University announced the world's first blue laser surgical equipment with an output power of 200W, which is used in the laser enucleation of urinary bladder tumors for tumor enucleation.
ams OSRAM also demonstrated a laser engraving module based on the blue laser chip assembly, the module can provide 20W, 30W, 40W, 50W output power, the output spot size of 50μm × 70μm ~ 80μm × 110μm, the focal length of 20 ~ 50mm between optional. This blue light module can be used for home DIY engraving machine, suitable for engraving metal, wood, paper, leather, plastic and many other materials; it can also cut wood, paper and leather with thickness less than 5mm. When the spot size is 50μm×70μm and the power is 40W, it can realize high-precision engraving on the surface of brass with a thickness of 1cm; when the focal length is 50mm, it can engrave metal and cut wood.
For industrial processing applications requiring higher power blue laser, the output wavelength of 445nm is suitable for welding, cladding and additive manufacturing applications of copper, gold and other metal materials. It is also possible to stack and combine multiple blue lasers together to achieve a power of kilowatts or even higher blue light module products, which for the largest application areas - lithium battery manufacturing in a variety of copper, aluminum and other high anti-corrosion materials welding link, to ensure the quality of the processing at the same time, to achieve higher processing efficiency.
In addition to the welding application of copper and other highly anti-materials, copper laser cladding and additive manufacturing, is also an important application area of blue light.
Future Trends
From the point of view of future market application demand, for the new energy vehicle lithium battery manufacturing in copper and other non-ferrous materials welding, is still one of the main application areas of blue laser. Lithium batteries in the lugs, busbar, top cover, module and many other welding links, the high demand for sealing, aesthetics, welding efficiency and other indicators, will prompt the blue laser toward a higher power, better beam quality direction. This will further promote the industry at the technical level is committed to higher power blue single-tube products, according to Xia Jie revealed that ams OSRAM has been in the development of higher power commercial blue single-tube.
In addition to enhance the power of blue single-tube, the single-tube array will be combined together, through the combined beam method, able to achieve kilowatt power, the industry has reported power up to 4kW of blue light products, and do a good beam quality. Therefore, driven by market demand, blue light combined beam technology will make more new breakthroughs.
Higher power, higher brightness blue light source, will be the mainstream lithium manufacturing in the processing quality and efficiency, to a new level. The emergence of higher performance blue light source, will also be outside the industrial processing of a wider range of fields, to develop more emerging applications, such as blue laser and red light, green light three-color synthesis, the formation of laser white light illumination, to achieve a more vibrant, brighter, more energy-efficient display color, can be used on the TV screen.
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