A design solution that achieves a breakthrough in light efficiency for LED lighting fixtures

The key to the development of LED chip technology lies in the substrate material and epitaxial growth technology. The substrate material has evolved from traditional sapphire materials, silicon and silicon carbide to new materials such as zinc oxide and gallium nitride. In just a few years, with the help of a series of technical improvements including chip structure, surface roughening treatment and multi-quantum well structure design, LED has achieved a huge breakthrough in light efficiency.

Reducing the cost of LED lights

LED chips account for a major part of the cost of LED lamps, so the main way to reduce the cost of LEDs is to reduce the cost of LED chips.

The key to the development of LED chip technology lies in the substrate material and epitaxial growth technology. The substrate material has evolved from traditional sapphire materials, silicon and silicon carbide to new materials such as zinc oxide and gallium nitride. In just a few years, with the help of a series of technical improvements including chip structure, surface roughening treatment and multi-quantum well structure design, LED has achieved a huge breakthrough in light efficiency.

The cost of silicon substrates is very low and the technology is constantly improving, but the current luminous efficiency is still unsatisfactory. If this development speed is maintained, once a higher level is reached, silicon substrates will become the most important technical solution and become an inevitable choice, and companies will also reap huge economic returns.

Improve the color rendering of LED lights

In high-brightness white LEDs, a small portion of the blue light has a longer wavelength after Stokes shift. This is a good thing, because it allows LED lamp manufacturers to use many different colors of phosphor layers, thereby expanding the emission spectrum and effectively improving the color rendering index (CRI) of the LED. The high CRI obtained by using phosphor white LEDs comes at a cost, because the Stokes shift causes the efficiency of white LEDs to be lower than that of monochrome LEDs. However, for most lighting applications, it is better to use LED lamps with high CRI but slightly lower efficiency.

Improving LED lighting system reliability

The overall efficiency, service life and reliability of LEDs must be improved through system optimization.

Light source: compact, efficient, choose the right color and output power.

Control and drive: Use electronic circuits to achieve constant current drive and control of LEDs.

Thermal management: To achieve a longer service life, the LED node temperature must be controlled. Heat dissipation model calculation and the use of new materials and new processes are hot spots in LED lighting technology.

Optical components: Lenses, reflectors or light guide materials focus light on a target area or disperse it around, depending on the design requirements.

Improving the efficiency of LED lamp power supply

Whether it is a current-limiting constant current controlled power supply or a constant current power supply controlled by an op amp, the power supply problem must be solved. That is, when the switching power supply chip is working, a relatively stable DC voltage is needed to power the chip, and the working current of the chip ranges from one MA to several MA. Like FSD200, NCP1012, and HV9910, this type of chip is high-voltage self-fed, which is convenient to use, but the high-voltage feeding causes the heat of the IC to rise, because the IC has to withstand about 300V DC. As long as there is a little current, even one MA, there will be 0.3 watts of damage. Generally, the LED power supply is only about ten watts, and the loss of a few watts can reduce the efficiency of the power supply by several points. A typical example is QX9910. , use a resistor to pull down to get power, so the loss is on the resistor, and it will lose about a few watts. There is also magnetic coupling, which is to use a transformer to add a winding to the main power coil, just like the auxiliary winding of the flyback power supply, so as to avoid the loss of these few watts of power. This is one of the reasons why a transformer is used when the power supply is not isolated, in order to avoid the loss of a few tenths of a watt of power and increase the efficiency by a few points.

As the problem of greenhouse gas emissions from the earth becomes increasingly serious and approaches the critical point of the earth's self-regulation, countries have introduced relevant policies one after another. Governments around the world, including my country, must urgently implement energy conservation and emission reduction (carbon dioxide). LED lights are currently the most energy-saving and green environmentally friendly electric light sources, and naturally become the main option for lighting energy conservation and emission reduction. As the cost and price of LED lights gradually decrease, their popularity is also accelerating. Before 2020, the market share of LED lights will exceed 50%.