Interpreting LED lighting technology from three aspects: chip, packaging and application

　　As LED lighting technology continues to develop and society pays more and more attention to the energy crisis, the LED lighting industry is experiencing a period of rapid growth, attracting a large amount of capital and enterprises to enter the market. As a result, competition in the lighting market is becoming increasingly fierce.

　　If we look at the development of LED lighting technology, we can talk about it from three aspects: chip level, packaging level, and application level. The chip level mainly focuses on the manufacturing technology of LED; the packaging level mainly focuses on how to convert LED chips into lamp beads or light sources that can be used for lighting; the technology development at the LED application level is relatively complex, mainly including the development of electronic control technology, the development and use of new materials, and the development and improvement of environmental lighting quality evaluation technology.

　　Chip level

　　The pursuit of high luminous efficiency has always been the driving force for the development of LED chip technology. Flip-chip technology is currently one of the main technologies for obtaining high-efficiency and high- power LED chips. Among the substrate materials, sapphire and its supporting vertical structure laser substrate lift-off technology (LLO) and new bonding technology will still dominate for a long time.

　　But in the near future, by adopting metal semiconductor structure, improving ohmic contact, improving crystal quality, improving electron mobility and electrical injection efficiency, and improving light extraction efficiency through roughening of LED chip surface and photonic crystals, high reflectivity mirrors, and transparent electrodes, the total efficiency of white light LEDs can reach 52%.

　　As the light efficiency of LEDs improves, on the one hand, the chips are getting smaller and smaller, and the number of chips that can be cut on a certain size of epitaxial wafer is increasing, thereby reducing the cost of a single chip. On the other hand, the power of a single chip is getting bigger and bigger. For example, it is 3W now, and will develop to 5W and 10W in the future. This can reduce the number of chips used for lighting applications with power requirements and reduce the cost of the application system.

　　In short, flip-chip, high voltage, and silicon-based gallium nitride will still be the development direction of semiconductor lighting chips.

　　Packaging level

　　Chip-level packaging, LED filament packaging, high color rendering index and wide color gamut will be the development trend of packaging technology in the future. The use of transparent conductive film, surface roughening technology, DBR reflector technology to improve the light efficiency of LED lamp beads is still the mainstream technology; at the same time, the COB/COF technology of flip-chip structure is also the focus of packaging manufacturers, and integrated packaged light engines will become the research and development focus of the next season.

　　Power-off solution (high-voltage LED), popularization of COB/COF applications: Driven by cost factors, power-off solution has gradually become an acceptable product, and high-voltage LED fully caters to the power-off solution, but it needs to solve the chip reliability. With the advantages of low thermal resistance, good light type, no soldering and low cost, COB application will be widely popularized in the future.

　　In addition, medium power will become the mainstream packaging method. Currently, most products on the market are high-power LED products or low-power LED products. Although they each have their own advantages, they also have insurmountable defects. Medium-power LED products that combine the advantages of both have emerged.

　　Another is the application of new materials in packaging. Materials with higher environmental tolerance such as high temperature resistance, UV resistance and low water absorption, such as thermosetting materials EMC, thermoplastic PCT, modified PPA and ceramic-like plastics, will be widely used.

　　Regarding the demand for light quality, for indoor lighting, the LED color rendering index CRI takes 80 as the standard and 90+ as the goal, and tries to make the light color of lighting products close to the Planck curve. This can improve the light quality of LEDs. In the future, indoor lighting will also pay more attention to the quality of light.

　　By optimizing LED packaging technology, the light efficiency is further improved, and it has now exceeded 200lm/W, which is much higher than other traditional light sources that are widely used. The heat dissipation performance of LED lamp beads will be further improved, the reliability will be further improved, and the life of the lamp beads will be further extended, thereby further improving the light color quality and ultimately improving the comfort of the human eye.

　　LED application research and development

　　Currently, application manufacturers mainly optimize the cost of LED lighting products by adopting new heat dissipation materials, advanced optical design and application of new optical materials, while ensuring product performance.

　　But in the future, LED lighting application manufacturers will focus on these points:

　　1. Interchangeable LED light engine technology based on application scenario requirements;

　　2. LED intelligent lighting system architecture technology based on the Internet of Things platform;

　　3. Development of LED lighting fixtures based on reliability design, and development of high-performance LED lighting fixtures that maintain color/brightness consistency during the use cycle;

　　4. Development of lamps based on large-area high-efficiency diffuser technology;

　　5. Lighting system solution technology and service system for online light environment experience;

　　6. The rich colors of LED light sources make scene lighting the core competitiveness of LED lighting.

　　Traditional lighting fixtures are designed around the shape and size of the light source and have fixed sizes.

　　The characteristics of LED lighting are:

　　The lamp has free shape and creative appearance;

　　The lamps are free in size and flexible in size;

　　The light quantity of the lamp is flexible and lighting can be provided on demand;

　　The lamp has a free spectrum and dynamic light colors;

　　The lamps can be positioned freely and installed at will.

　　In the future, the shape of LED lamps will no longer be limited to the shape of traditional lamps, but will tend to be free and hidden. Free shape can meet individual needs on the one hand, and can be used as decoration on the other hand; and the hidden nature of LED will make the lighting fixture hidden in the form of embedded but ubiquitous.

　　At the same time, LED lighting products can realize arbitrary control of light lumens and are no longer limited to a fixed wattage in a certain area or scenario. This will be a great technological advancement.

　　Smart lighting: future development trend

　　Smart lighting refers to the use of smart clients to collect, process and control information, and achieve safety, energy saving, health and comfort through functions such as lighting brightness adjustment, light switch distribution control, spectrum adjustment control, scene setting, etc.

　　The characteristics of intelligent lighting technology include distribution, remote control and telemetry, openness, compatibility, interactivity, etc.

　　To achieve smart lighting, it is necessary to have client intelligent operation technology and data collection technology, Internet data transmission technology, cloud big data management and analysis technology, and customer online experience situational lighting technology. Only with these technologies as the basis can smart lighting be truly realized.

　　The requirements for intelligent lighting in the future are personalized display, simple control, and emotional sensing.

　　Home lighting has simple lighting requirements and is easy to control, so smart LED lighting will start from here. However, with the development of technology, a good lighting system will be needed even in public places in the future. For example, the demand for intelligent outdoor landscape lighting is very high, but technology is difficult to meet the demand.

　　How to break through the technical bottlenecks and price barriers of smart lighting in public places such as outdoor lighting and commercial lighting has become an urgent problem to be solved.

　　Intelligence is an inevitable trend in future life. The intelligence of LED lamps is only a small part of the intelligence of various home appliances. Enterprises must make lamps intelligent and diverse through technological research and development to meet the personalized needs of customers. However, due to the high cost and poor product matching of intelligent lighting technology, LED intelligent lighting products cannot be popularized.

　　As technology improves, product performance becomes more stable, and costs decrease, intelligent LED lamps will surely be widely circulated in the market. Whether LED companies have mastered intelligent lighting technology and designed products and intelligent control systems that meet market demand will largely determine whether the company can develop in the long term.

　　From the perspective of usage scenarios, different scenarios have different lighting requirements. As a "torrent" of LED lighting, the development of LED indoor lighting has gone through three main stages:

　　1. Improve product performance.

　　During this stage, LED companies focused on improving product performance and ensuring the lighting quality of LED products, such as improving the performance of LED light sources, MR16 lamp cups, and LED modules.

　　2. Optimize costs.

　　At this stage, enterprises should try to shorten the product recycling cycle, increase their own product capacity, and produce cost-effective products that are accepted by customers by improving product research and development technology;

　　3. Leading the digitalization of light.

　　There are three important indicators for measuring the quality of indoor lighting: physical indicators, physiological indicators and psychological indicators. Different lighting environments will affect consumers' physiological indicators such as heart rate and blood pressure, thereby affecting consumers' psychological comfort. In lighting applications, physiological indicators and psychological indicators are more important.

　　In the future, indoor lighting will not focus too much on light effects, but will pay more attention to the quality of light, pay more attention to the emotional experience of customers, create a pleasant environment through the perception of light, and the color difference of lamps in different viewing directions. The color difference, color drift and flicker of LED products themselves will affect the indoor lighting effect.

　　At present, the application technology of domestic LED lighting is relatively scattered, and homogeneous products and inferior products are flooding the LED lighting market, resulting in market chaos and disorderly competition. Many domestic LED companies are in the learning stage, rather than independent innovation. Many small and medium-sized enterprises focus on short-term interests, and on the other hand, they do not have enough resources and time to invest in product research and development, resulting in uneven LED products. The quality and performance of LED products of international lighting companies, especially in optical design and product intelligent control, are superior to domestic products.

　　In response to this situation, small LED companies can develop their businesses in the early stages by purchasing technology from industry associations or relying on their marketing strength. When the company reaches the medium-sized stage, it needs to change its development strategy, conduct in-depth market research, clarify the future development trend of LED lighting products, actively invest a lot of resources to enhance R&D capabilities, and compete with other competitors in the LED lighting market.

　　The LED lighting industry will continue to integrate resources. The leaders of LED lighting companies must have keen market insight, increase investment to enhance product research and development capabilities, and accumulate core competitiveness in order to be invincible in future competition.