From the perspective of LED bulbs (E26 socket products) manufactured by Japanese manufacturers such as home appliances stores, products with a simple design without heat sinks are gradually increasing. Moreover, products with the same lighting angle as the incandescent bulbs are expected to increase in the future.
LED bulbs manufactured by Korean, Chinese, and Taiwanese manufacturers are dominated by products that use large and heavy aluminum die-cast heat sinks. Recently, I have the privilege of disassembling the LED bulbs manufactured by these overseas companies and comparing them with those made by Japanese manufacturers (Toshiba Lighting ). Let's take a brief introduction.
At first, I thought that the simple LED bulb made in Japan wanted to reduce the cost by eliminating the heat sink, but now I think it is wrong. Because aluminum die-cast heat sinks are not expensive parts. On the contrary, since the heat sink is omitted, the outer casing will be formed at a high temperature, and the internal power supply module needs to use a component having high heat resistance, so that the overall cost will not fall. From the perspective of Toshiba Lighting, its LED components use a COB (Chip On Board) product with high luminous efficiency to suppress heat generation. It can be said that the simple LED bulb manufactured in Japan improves the industrial design performance by using expensive components.
The overseas LED bulbs adopt a structure that places great emphasis on cost reduction. It is manifested in the fact that many designs rarely use large-sized LED chips . The most costly component of LED bulbs is LEDs. Therefore, overseas products mostly reduce the cost by increasing the input power of each LED chip to increase the brightness while reducing the number of LED chips. At this time, the luminous efficiency of the LED will decrease, and the amount of heat will increase accordingly, so it is necessary to provide an aluminum die-casting heat sink with high heat dissipation capability. In addition, due to the small number of LEDs, the uniformity of light will also decrease.
This time, I used a thermal imager to detect the surface temperature of the LED bulb in the lighted state. The results show that South Korea's Samsung LED 7.1W product (540lm) equipped with aluminum die-cast heat sink is 47 ° C, while Toshiba lighting 7.2W product (600 lm) without heat sink and thin aluminum plate shell is as high as 61 ° C. Because of the different design concepts, it is not easy to say that it is better or worse, but this difference is true. Toshiba Lighting simplifies the heat sink by setting the surface temperature of the case to the highest extent without causing problems.
Then, this involves the problem that "the LED bulb has a heat sink will be better". The author thinks that it cannot be generalized and asserts whether the heat sink is good or bad. At least for the manufacturers, if there is a heat sink, it is easier to reduce the cost. When users buy low-priced products, they will buy LED bulbs with heat sinks. However, attention should be paid to the luminous efficiency and uniformity of light. On the other hand, if you pay attention to the shape design and luminous efficiency of the bulb, the new LED bulb without heat sink is the best option. Personally, I think there is also a heat sink, but I hope to get a cheap and luminous LED bulb.
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