[Text / high-tech LED Xu Chaopeng] Previously, the father of blue LED, Nakamura Shuji, said in the seminar "The GaN Energy Revolution", "The white LED technology using blue LED will disappear sooner or later." Lively discussion.
Some analysts pointed out that Nakamura Shuji, who won the 2014 Nobel Prize in Physics for inventing blue LEDs, is now "overturning" his research results, perhaps because of the promotion of the purple LED that Soraa company founded. (According to the author, the US Soraa company is a LED venture company established by Professor Nakamura and three UCSB professors as co-founders)
However, there are also many people in the industry who support Nakamura Shuji. "As a scientist who won the Nobel Prize, it should have a high moral standard and professional ethics. Because he sees the huge prospect of purple LED, he will invest in such a Purple LED research and development based company." Wang Liyang, director of Hongli Optoelectronics, mentioned.
In any case, as a well-known scientist, we also believe that his judgment should be based on his understanding and starting point. For his view of the blue LED, as long as it has theoretical support, it is naturally reasonable. Sex. But 'blue LED' is not good, what is purple LED?
The father of blue LED - Nakamura Shuji
According to the data, the advantages of purple LED are mainly: two characteristics: high color rendering index and high luminous efficiency.
Among them, the high color rendering index is mainly reflected in the way that the purple LED obtains the white LED by exciting the phosphor with the purple LED to obtain the blue light, and the peak intensity of the blue light is not too high, and the purple LED can output the visible wavelength range. All the light, so the color rendering index is relatively high, can achieve the ideal white like the sun. It is understood that the red color rendering index R9 of this purple LED is particularly high, and the average color rendering index Ra is also as high as 95.
Another feature of the purple LED - high luminous efficiency is reflected in the following four points:
1) The purple LED is made of a GaN substrate, and a GaN-based semiconductor is stacked on a GaN substrate to produce a purple LED chip, which belongs to a "GaN on GaN" type LED, and the GaN-based semiconductor layer has a relatively high crystal quality, so that the purple LED has high luminous efficiency. And the efficiency is improved fast;
2), the purple LED chip is triangular, and the shape of the ordinary LED chip is a quadrangle, compared with the efficiency of the light emitted from the light emitting layer of the triangular LED chip to the off-chip (light extraction efficiency) is higher;
3) Ordinary blue LED chips are fabricated on sapphire substrates. GaN-based semiconductors and sapphire have different lattice constants, so crystal defects called "dislocations" are prone to occur, and there are almost no crystals in GaN substrates. The difference in lattice constants, so crystal defects are difficult to occur, and the dislocation density can be reduced to about 1/1000 compared with products using sapphire substrates;
4), the purple LED chip is not easy to appear "light effect (droop)" problem. The decrease in luminous efficiency is a phenomenon in which the luminous efficiency is lowered when the driving current density is increased to increase the luminous intensity, and is also a major problem in improving the brightness, and the "GaN on GaN" type product has a high crystal quality and a sapphire substrate. Compared with the type products, the problem of light efficiency degradation is less likely to occur. In general, GaN substrate type products can increase current density by a factor of 5 to 10 compared to sapphire substrate type products.
"Purple light conversion white light is more efficient, the spectral distribution is balanced, and the color rendering index is relatively good, which is of great significance for energy saving and emission reduction and improvement of light quality. Although it is currently affected by high prices, it has not yet been popularized, but the advantages are obvious." Wang Gaoyang has a positive attitude towards the development prospects of purple LED.
Hongli Optoelectronics' deep ultraviolet LED can effectively inhibit the growth of static water bacteria
Hongli Optoelectronics, where Wang Gaoyang is located, is also in the process of developing the purple LED product line. As a domestic packaging manufacturer of deep-UV LEDs, Hongli Optoelectronics not only has a large-scale production line of deep-UV LEDs, but also has its own professional microbiology testing laboratory, and can provide customers with the best for deep-UV LED applications. Apply the solution and verify the solution to help the customer confirm the feasibility of the solution.
Therefore, we also believe that in the use of violet or ultraviolet LED to stimulate RGB three-color phosphors, to obtain high-color white LED technology, in the current chip efficiency has been increased to a new level, purple LED will gain more and more in the industry More favor.
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