It is more practical to mention the types of LEDs in somewhat chronological order, so those who are immediately interested in SMD LEDs can find them at the bottom of the page.
DIP LED
The most well-known LED form, which is also the oldest type. Originally, it functioned as an indicator light for electronic devices. The industry considers the lifespan of these traditional (usually 3-5mm diameter) epoxy-housed LEDs to be the shortest. If this weren’t the case, as the oldest types, only these would exist, and new solutions wouldn’t have been developed. Of course, these DIP LEDs are also constantly being developed, and they are capable of emitting increasing luminous flux. Moreover, to ensure higher luminous flux, the so-called dual-chip DIP LED was created. This is practically two LEDs built into one, thus capable of emitting double the luminous flux from one spot. This encapsulation of multiple chips has proven to be a successful solution for other types as well. In this case, its peculiarity is that its size remains the same as if there were only one chip in the epoxy housing. Thus, theoretically, we can achieve double the luminous flux from the same spot, but this also comes with double heating, which raises doubts about the expected lifespan.
The industry considers DIP LEDs to have a short lifespan because the light and heat generated in a small area, due to their small size, result in poor heat dissipation, and the continuous oxidation of the epoxy housing, the lens, leads to a decrease in luminous flux. Against the problem of heat dissipation, it is argued that the excellent (in many cases perhaps the highest) efficiency of DIP LEDs results in very little heat generation. Even after prolonged illumination, DIP LEDs are touchable, just warm, not hot, and manufacturers haven’t even installed heat sinks on them. In contrast, the Power LEDs introduced below, and increasingly more powerful SMD LEDs generate so much heat that they are unusable without heat sinks, as they would quickly deteriorate. The advantage of DIP LEDs over other solutions is that practically any lighting angle LED can be manufactured within a 120-degree spatial angle without a separate lens or mirror structure. That is, the head end of the epoxy casing is shaped into a lens form, and the distance between the light source and the lens, as well as the curvature of the head end (i.e., lens), determines the lighting angle. Most commonly, DIP LEDs with lighting angles of 120, 90, 60, 38, 30, and 15 degrees are found.
SuperFlux LED
The lifespan of SuperFlux packaged LEDs is considered somewhat better due to their larger size and more favorable heat dissipation. However, like DIP LEDs, they are also made of epoxy material, where continuous oxidation reduces their output luminous flux. SuperFlux LEDs are similar to DIP LEDs, as if 3 chips were encapsulated together, but naturally in a larger size to ensure more favorable heat distribution.
Power LED
Power LEDs, also known as High Power LEDs, form a category that is not precisely defined. In Hungarian, we could call them performance LEDs. Some consider any LED of 0.5 Watts and above to be a Power LED, while others consider those of 1 Watt and above. This category can include SMD LEDs, especially grouped SMD LEDs and COB LEDs. In a narrower sense, a group of lens-packaged LEDs, similar to DIP LEDs, but larger, more powerful, and more reliable with a longer lifespan, appeared before SMD LEDs. Various manufacturers develop these performance LEDs according to their own research, thus giving them different brand names such as Edison, CREE, Luxeon, LumiLeds, Epistar, Sharp, etc.
A correct assessment is determined not only by the material usage mentioned earlier, the chip temperature, and the cooling options but also by several other factors.
The quality of LED manufacturing, that is, the contamination of the semiconductor, is also important. Particularly for higher heat-producing SMD LEDs and Power LEDs, it is crucial to use them in places where the heat dissipation of the heat sinks is ensured. High external environmental temperatures, such as in a sauna, shorten the lifespan of all types of LEDs. The current strength driving the LED is also a lifespan-determining factor; higher current can provide greater luminous flux, but this may come at the cost of a shorter lifespan. The quality of the driver circuit and its components is important as well. For instance, the electrolytic capacitors in the driver circuit have a lifespan of a few tens of thousands of hours. So it can happen that the LED could still shine with sufficient brightness, but the driver component no longer works.
SMD LED
SMD stands for Surface Mounted Diode. The situation with SMD packaged LEDs is more favorable in that this type no longer has an epoxy lens. Nevertheless, a decrease in luminous flux cannot be ruled out, but this can only be traced back to material changes at the atomic level.
This LED technology has greatly facilitated and continues to facilitate the spread of LED lighting technology. Currently (in 2012/2013), it may be the most viable alternative to mercury vapor-based energy-saving lighting. Not that the activities of world-renowned Power LED developers don’t act as a driving force, but their price range can only ensure limited dissemination. In contrast, many non-name manufacturers (LED lamp assemblers) use SMD chips because of the more favorable prices, and in this sense, they can be expected to spread more widely compared to Power LEDs. This does not mean that the manufacturing background of SMD LED chips is weaker, as world brands (e.g., Edison, Samsung) are also found here. During automation, manufacturers achieved such favorable volumes that reduced production costs while continuously improving quality control, resulting in products with better heat conduction, higher luminous flux, and longer lifespans. Moreover, it is noticeable even to the lay buyer (unlike with DIP LEDs) that the light sources (chips) have moved in the direction appropriate to the intended use. SMD chips are not only found in individual packaging but also form groups, similar in appearance to COB LEDs. Consequently, this technical solution led to the development direction of COB LEDs, enabling even more advantageous physical parameters.