How to reduce the cost per unit lumen of LED

LED lighting prospects

The U.S. Department of energy (DOE) has made such a rating on LED: no other lighting technology can have such a big energy saving potential like LED and improve the quality of our building environment.

For LED packaging, in 2010 the growth rate of more than 50%, more than $8 billion, by 2014, the LED market CAGR of more than 30%, the amount of more than $20 billion. According to DisplaySearch's latest report shows that due to the LED chip power improvement and cost reduction, each LCD TV backlight use LED devices will be reduced, is expected to 2014 LED lighting applications will replace the LCD TV backlight applications become mainstream LED application.

Four elements of LED quality

At present, there are a lot of parameters to evaluate the quality of LED, which is mainly the following 4 aspects: LED service life, luminous efficiency, color rendering index, color temperature and so on. To improve the quality of LED, we must start from the above four aspects, this paper from the perspective of LED package, mainly focuses on the thermal management of packaging, to improve the quality of LED and reduce the cost per lumen.

LED is a photoelectric conversion semiconductor device, only the 10~40% in the process of working electric energy into light energy, the other almost all electrical energy converted into heat, resulting in LED temperature, LED temperature rise is mainly caused by LED failure and performance. LED overheating LED will affect the short-term and long-term performance, the short-term will affect the luminous efficiency and color offset LED; deterioration of defects and packaging materials will lead to long-term chip, seriously affect the service life and reliability of LED. With the increase of the operating current of a single device, the heating of the device will increase, which leads to the increase of the LED junction temperature and the decrease of the luminous efficiency. Therefore, the thermal management of LED devices is the key to reduce the cost per unit lumen.

Method for reducing unit lumen cost from packaging point of view

At present, the mainstream manufacturers of 1W high power LED chip price is still high, according to the current price, even if the price is also reduced by 50% is still high, in the short term, the possibility of high power chips diving price is small. From the packaging point of view, the price of a single device continued to decline in space is limited, so the price of the chip or a single device to reduce the price of the way to reduce the cost per unit of the lumen of the road is difficult to go on. Here are two possible ways to reduce the cost per unit lumen:

1, from the aspect of the chip, we must improve the current density of a single chip, so that the 1W chip can work under 700mA or 1000mA, and only a small reduction in light efficiency.

2, from the packaging point of view, as far as possible to reduce the size of the device, while reducing the thermal resistance of the entire device, so that a single device to support a greater current, a single device power up to 3-5W, thereby reducing the cost of the entire package.

The ultimate aim is to maintain and enhance the luminous efficiency in the case, to enhance the cooling capacity of LED device, the device in the package is small, light, thin, high efficiency, high current, high power. At present, some manufacturers based on ceramic heat dissipation structure of 3535 (T1901PW) size SMD type high-power devices, has been able to achieve 700mA work, luminous flux of 220lm. At the beginning of 2012 increased to 1050mA above the flux 300lm.

You can also use different packaging process, according to the measured resistance performance of the 3535 devices can be seen using flip eutectic, low thermal resistance to 2.5 DEG /W, this device works even under the condition of 1050mA, the heat dissipation is good, junction temperature and device bottom temperature still does not exceed 10 degrees.

In terms of power devices, improve the device current density is an effective way to reduce the cost per lumen, to adopt new static photoelectric materials with high thermal conductivity (T3400SW) of the 3020 power LED product size in the SMD case, because T3400SW has low thermal resistance, excellent temperature resistance heat resistance, still maintain high photosynthetic efficiency in under the current conditions. At present, the typical luminous flux 20lm@60mA, in early 2012 will be raised to 50lm@150mA, to the current level of view, the cost per unit luminous flux is equivalent to about half of the 20mA device. Has obvious advantages and disadvantages.

Conclusion:

According to the current understanding of the technology and products have achieved results, SMD LED will be the future main type LED package, high power LED packaging products mainly to the development of small and thin, high power, high brightness. At the same time in order to reduce manufacturing costs as soon as possible, the scale is also necessary, the scale is at least 1W of 50KK per month or more high-power LED production capacity. With the development of chip and packaging technology, it is possible to achieve the power of 3535 3-5W devices.

After the realization of the above indicators, the era of LED industry 100lm/1RMB will come, which will have a great role in promoting the popularization of LED in the field of lighting for the development of the entire industry to make a huge contribution to the LED.