Unpackaged LED will show up

As LED lighting is increasingly seeping into the home market, the use of high-power LEDs is also increasing day by day, and technology is continuously improving. One of the major developments is the gradual reduction of LED size. However, high power generates more heat than low- and medium-power LEDs, and chip sizes are getting smaller and smaller. This causes heat to be increasingly concentrated on small-sized chips, resulting in higher heat densities and LED lighting. Thermal management of products is facing increasingly severe challenges. Once improperly handled, the lifespan of LED lighting products will be seriously affected.

From the perspective of LED lighting design, in order to make LED lighting popular, LED lighting products are mostly based on the size of the traditional light source or lamp shape, but compared to traditional lighting, LED also need to use optical accessories and electronic circuits The combination of components can shine, and more components must be placed in the same space, thus reducing the space for heat dissipation.

Space shrinks, passive cooling technology is popular

Under the limitation of the size of the traditional lighting design, how to make the LED lamp's heat sink perform high-efficiency heat conduction, heat convection and heat radiation in a limited space has become one of the important tasks of LED lamp manufacturers.

Due to the influence of the 3C industry, the heat dissipation of early LED lamps did not consider the aesthetics, and only the heat dissipation performance was considered. Therefore, it is emphasized that the larger the heat sink is, the better the heat exchange fins are. However, in addition to performance considerations, current LED heat dissipation needs to be more aesthetically pleasing. The design of finned heat sinks is no longer the only mainstream. Instead, it is a smoother, streamlined, and conventional heat dissipation technology. It also evolved from increasing heat conduction, thermal convection, to increasing heat radiation.

It is for these reasons that LED heat dissipation technology is still mainly based on passive heat dissipation in recent years. In order to get closer to the design of traditional lighting, emphasis has been placed on lightweight design and high-standard safety design, and lightweight technology has also emerged in heat dissipation technology. High thermal conductivity composite material.

Everlight Electronics Industry Co., Ltd. is currently based on the use of passive cooling technology, the company's industrial lighting manager Liang Jiahao said, Yiguang is based on high-tech computer simulation analysis to design the structure, after the reliability and safety assessment and assessment Subsequent mold opening and production, the current use of heat-dissipating material is mainly aluminum products, if there are special needs will use composite coatings.

Compared with the advantages and disadvantages of passive heat dissipation and active cooling technologies, in general, passive heat dissipation has the advantage of high stability. The disadvantage is that for space-constrained designs, heat dissipation capability has its limits; In terms of design, although the heat dissipation capacity can be overcome by increasing the heat dissipation volume, it also faces the problems of weight and unit price.

As for the advantage of active heat dissipation is its strong heat dissipation, but its reliability is not high, so it still can not be favored by the industry vendors. This is because in the active heat dissipation technology, a group of parts means that there is one more variable in stability. In addition, whether or not the noise of multiple lighting fixtures at the same time will affect the operation of the active heat dissipation technology also needs to be increased. Considerations.

In addition to the choice of heat dissipation technology, the ultimate solution to LED heat dissipation lies in the LED body. As long as the efficiency of the LED is higher, the corresponding waste energy (heat) is less. In this regard, Everlight has also actively introduced and developed ultra-efficient LED components to increase efficiency and reduce waste heat generation. In the field of LED lighting, Everlight's A60 bulbs can now achieve luminous efficiencies of more than 100 lm/W. In LED lighting fixtures, Everlight's LED street lamps can now achieve lighting efficiencies of 130 lm/W.

Unpackaged LEDs Reduce Package Thermal Resistance

It is worth mentioning that TSMC's subsidiary, TSMC Solid-State Lighting, has announced that it will mass-produce LED light sources without packaging in the second half of this year after mass production of silicon-based gallium nitride LEDs. This will be an LED light source technology. Great progress.

In order to improve the heat dissipation performance of high-power LEDs, in general, high-power LED suppliers must achieve thermal targets by selecting low-thermal-resistive substrates and lowering the thermal resistance of the packages, while TSMC solid-state lighting utilizes high-radiation silicon substrates for mass production. Power LED, adopting non-wire COB packaging technology, can reduce the thermal resistance of the package.

Tan Changlin, general manager of TSMC Solid-State Lighting, stated that in the future, the technical problems of reducing the thermal resistance of the package will be solved by eliminating the manufacturing process of the package. In addition, the LED die with less package body can be directly integrated into the heat dissipation module, simplifying the manufacturing process. Under the circumstances, the overall cost will be significantly reduced and it is expected to challenge the target of 1000 lumens/US dollar.

In addition to TSMC solid-state lighting, LED maker Cree is currently actively investing in the development of LED light sources without packaging. In the LED lighting application market, the product price will be the key for the manufacturer to win the market. Without packaging, the cost of the LED light source packaging process will also be saved (the estimated cost will be reduced by 15% for customers). Therefore, compared to Traditional LED light sources will be more competitive in price, and it is expected that the mass production without packaging LEDs will have a huge impact on LED lighting applications.

In general, in order to replace traditional lighting fixtures, LED lighting products must be close to the needs of the general public in terms of price. Therefore, in the future development of cooling technology, it is expected that the new cooling technology will replace the existing cooling architecture. Instead of blindly pursuing high-performance heat-dissipating technologies, the low-cost, high-reliability, thermally conductive composite materials will be one of the major trends in the future. However, the most basic factor is the need to continuously promote the efficiency of LED components and the increase in lumens per dollar (lm/$). This is the main goal of LED lighting development.