Several key technologies for making good LED lighting products

If you want to make a good LED lighting product, you must know the most critical parts, which are light distribution, structure, and electronics. Light distribution, structure, and electronics are expressed in professional terms as: optical performance, thermal performance, and electrical performance. At the same time, light distribution is particularly important. If you don’t understand light distribution, you can’t make good LED lighting.

Optical performance (light distribution): The optical performance of LED mainly involves the performance requirements of spectrum, photometry and chromaticity. According to the newly formulated industry standard "Test Method for Semiconductor Light Emitting Diodes", the main parameters include peak wavelength, spectral radiation bandwidth, axial luminous intensity angle, luminous flux, radiant flux, luminous efficiency, chromaticity coordinates, correlated color temperature, color purity and dominant wavelength, color rendering index and other parameters. LEDs used for display are mainly for visual intuitive effects, so there is no requirement for the relevant color rendering index. For white light LEDs used for lighting, color temperature, color rendering index and illumination are particularly important. They are important indicators of lighting atmosphere and effect, while color purity and dominant wavelength are generally not required.

At present, the mainstream practice in the global LED industry is to package LED chips to form light sources or light source modules, and then distribute the light when the lamps are made. This is the original practice of traditional light sources, because traditional light sources emit light at 360 degrees. If light is to be guided to the application end, the light loss of Philips's best traditional lamps is 40%. The optical parameters of lamps used by many LED downstream manufacturers in China are actually the optical parameters of chips or light sources, rather than the optical index parameters of the overall lamps.

The most advanced scientific method now is to do light distribution on the chip package, guide the light of the chip out at one time, maintain the maximum light output, so that the light loss rate is only 5%-10%. With the continuous improvement of technology, the light loss rate will become lower and lower, and the light efficiency of the light source will become higher and higher. Similarly, lamps equipped with such light sources do not need to do light distribution, and the relative efficiency of lamps will be greatly improved, making them more widely used in functional lighting, forming a considerable market channel. Therefore, a good LED supplier is our top priority. We don’t need to spend a high price to study how to distribute the light of our LED, nor do we need to spend a lot of time and experience to let engineers use software simulation. The simplest way is to let the LED white light supplier cooperate. You must know that if our engineers use software to simulate, then the necessary actions are input and output. Input is the import of early data, and output is the result of simulation. Therefore, the early data must be accurate for the back-end simulation to be correct.

Thermal performance (structure): The luminous efficiency and power of LEDs used for lighting are one of the keys to the LED industry. At the same time, the PN junction temperature of LEDs and the heat dissipation of the housing are particularly important. The greater the difference between the PN junction temperature and the temperature of the lamp body, the greater the thermal resistance, and the light energy is converted into heat energy and consumed in vain. In severe cases, the LED is damaged. A good structural engineer must not only consider the structure of the lamp and the thermal resistance of the LED, but also consider whether the shape of the lamp is reasonable, fashionable, and novel, and of course reliability, maintainability, and practicality. That is, he must think from the perspective of the designer and consider the product from the perspective of the user.

At present, upstream leading enterprises, such as CREE, can achieve chip luminous efficacy of 130-150lm/W. However, the junction temperature of LED directly affects the light output efficiency, device life, reliability, emission wavelength, etc. of LED. Keeping the junction temperature of LED within the allowable range is a key factor that must be studied in every link of high-power LED chip preparation, device packaging and device application, especially the core problem that must be solved in LED device packaging and device application design.

The mainstream application technology material is now packaged with aluminum substrates, but there are technical core bottlenecks in the heat dissipation and light conversion efficiency of the chip packaged with aluminum substrates. It cannot effectively control the junction temperature and stably maintain high-power light output. In addition, the application will be extremely inconvenient because the higher the chip light efficiency, the larger the area of ​​the aluminum substrate required, which will increase the cost and application volume. Therefore, how to get out of this misunderstanding and open up a new path is the core feature of the new technology. Under the premise of maintaining low cost and passive heat dissipation, using high thermal conductivity media, through a brand-new device/lamp overall structure, reduce thermal resistance, reduce PN junction temperature, make the PN junction work within the allowable operating temperature, and maintain the maximum amount of photon output. The minimum requirements are as follows:

(1) Ultra-low thermal resistance material, fast heat dissipation overall structure technology;

(2) High thermal conductivity and UV-resistant packaging technology;

(3) Apply low environmental stress structural technology;

(4) Overall thermal resistance <20K/W, junction temperature <80 degrees;

(5) The operating temperature of the LED light source lighting module is controlled below 65°C.

Electrical performance (electronics): If a lighting fixture is likened to a girl, then the light distribution is her connotation, the structure is her appearance, and the electronics is her heart. (People's eyes are always attracted by those beautiful and fashionable beauties, and the same is true for products). Without a heart, a person has no life, and without electronics, a lamp cannot be a power source. A good driving power source can also determine the life of a product. The standards and parameters of electronics are often much more complicated than the structure, and the initial R&D energy investment is also relatively large. The current technological trends and updates are changing with each passing day... Engineers have to spend a lot of energy to learn, absorb, decompose, and apply new technologies. The early planning, mid-term implementation, and late-stage molding of electronic design require the formation of documents and data, which is also the most tedious thing in design. For example: a preliminary plan for a power supply design, product introduction, standard specification basis, safety specification basis, electrical performance expectations, process requirements, raw material evaluation, test methods, etc. must be formed into a system file.

In the field of LED driver power supply, the development path of Maoshuo Power Supply, which is now the industry leader, is full of legends. With a keen sense of the LED industry, Maoshuo Power Supply's head Gu Yongde led his team to invest in the research and development of LED power supplies in 2006. Today, Maoshuo Power Supply's world-leading technology has led the trend of LED street lamp intelligent drive, and proposed to provide the most reliable intelligent drive solutions for LED street lamp manufacturers, which is another example of leading ideas.

LED driver power supply is powerful

As the core component of LED lamps, LED power supply is like the heart of LED. The quality of LED driving power supply directly determines the quality of LED lamps.

First of all, in terms of structural design, the outdoor LED driver power supply must have strict waterproof function, otherwise it cannot withstand the harsh external operating environment.

Secondly, the lightning protection function of the LED driver power supply is also crucial. When working outside, it is inevitable to encounter thunderstorms. If the driver power supply has no lightning protection function, it will directly affect the life of the LED lamp and increase the maintenance cost of the lamp;

Finally, in the selection of raw materials, their reliability must meet the life requirements, and the functional characteristics must be good enough. At present, the theoretical life of LED chips is about 100,000 hours, and if the life of components in the industry is to match this, the selection of key components must be subject to perfect DMT and DVT verification management to ensure long life and product reliability requirements. Otherwise, the life of the power supply is not enough and the life of the lamp cannot be achieved.

Therefore, the reliability of LED driver power supply (electronic design) is the foundation for supporting the development of LED. Only when LED driver power supply is energy-saving, efficient and has a lifespan superior to traditional lamps can LED truly achieve energy saving and consumption reduction and promote the development of the industry. LED heat dissipation (structural design) is the key to determining the light flux maintenance rate, component and equipment safety. LED light distribution (optical design) is a symbol of the industry's technical level. Mastering the above three technologies will make LED lighting simple.