The five elements determine the technological development direction of LED lamps

The future of LED lights

With the growing problem of global greenhouse gas emissions, approaching the critical point of self-regulation of the earth, various countries have issued relevant policies one after another. Governments around the world, including China, must implement energy conservation and emission reduction (CO2) without delay. The LED lamp is currently the most energy-efficient. Green environmental protection electric light source naturally becomes the main option for energy saving and emission reduction of lighting. With the gradual reduction of the cost and price of LED lamps, the speed of popularization is also accelerating. By 2020, the market share of LED lamps will exceed 50%.

Reduce the cost of LED lights

LED chips occupy 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 is base material and epitaxial growth technology. The base material is developed from traditional sapphire materials, silicon and silicon carbide to new materials such as zinc oxide and gallium nitride. Within a few years, LED has achieved a great breakthrough in light efficiency with a series of technological improvements including chip structure, surface roughening and multi-quantum well structure design.

The cost of the silicon substrate is very low, and the technology is continuously improving. However, the current luminous efficiency is not yet satisfactory. If this rate of development is maintained, once the high level is reached, the silicon substrate becomes the most important technical solution and becomes an inevitable choice. The company will also Get a huge economic return.

Improve the efficacy of LED lights

Improving light efficiency can also start with increasing the proportion of effective light. The thin-film chip technology can reduce the light output loss of each side, with the bottom of the reflective surface to make more than 97% of the light output from the front, so that most of the light obtained by the electrical energy conversion is an effective light, not only significantly improve the efficiency of the LED, It also creates superior convenience for lens design. Thin film chip technology is currently the core technology in the production of ultra-bright LED chips.

Improve the color rendering of LED lights

In high-brightness white LEDs, a small fraction of 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 to extend the emission spectrum and effectively increase the color rendering index (CRI) of LEDs. The high CRI obtained with phosphor-based white LEDs is costly because Stokes shifts cause white LEDs to be less efficient than monochromatic LEDs. However, for most lighting applications, LED lamps that prefer high CRI and slightly lower efficiency are preferred.

Improve the efficiency of LED lamp power supply

Whether it is to do current limiting constant current control power supply, or op amp controlled Constant Current Power Supply, we must solve the power supply problem. That is, when the switching power supply chip works, it needs a relatively stable DC voltage to power its chip. The operating current of the chip varies from one MA to several MAs. Like the FSD200, NCP1012, and HV9910, this type of chip is self-fed with high voltage, which is convenient to use, but the high-voltage power supply causes the IC's heat to rise because the IC is subject to about 300V of direct current, as long as there is a little bit of current, even if One MA also has a loss of 0.3 watts. The general LED Power Supply, however, is about ten watts. A loss of a few tenths of a watt can pull down the power supply efficiency by several points. Typical like the QX9910. Pull down the power with a resistor, so that the loss is on the resistor, and it must lose about a few tenths of a watt. There is magnetic coupling, that is, using a transformer, add a winding on the main power coil, just like the auxiliary winding of the flyback power supply, so as to avoid losing the zero-watt power. This is one of the reasons why the transformer is not isolated from the power supply. In order to avoid losing the power of a few tenths of a watt, the efficiency is increased to several points.

Improve LED lamp system reliability

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

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

Control and Drive: Use an electronic circuit to achieve LED constant current drive and control.

Thermal Management: To achieve a longer lifetime, LED node temperature must be controlled. Thermal model calculations and the use of new materials and processes are LED lamp technology hotspots.

Optics: Lenses, reflectors, or light guide materials focus the light on the target area or on the periphery, depending on the design requirements.

With the rapid development of LED technology and the gradual improvement of LED light efficiency, the application of LED lights will become more and more extensive. In particular, with the increasing global shortage of energy, LED lamps will be an inevitable choice to replace incandescent, tungsten and fluorescent lamps. In addition, in terms of indoor lighting design, LEDs will tend to be intelligent, diverse, and artistic.