Refers to the blue LED. The center of the emission wavelength is around 470 nm. A light source for a blue display portion such as a lighting fixture and an indicator, a blue light source for an LED display panel, and a backlight source of the liquid crystal panel. Use in combination with a phosphor material to obtain white light. Current white LEDs generally use a combination of blue LEDs and fluorescent materials. battery pack current sensor,battery current sensor function,battery current sensor test,allegro current sensor Shanghai Zhilong Electronic Technology Co.,Ltd , https://www.zhilongsensor.com
The opportunity for the wide application of blue LEDs was the first time in 1993 that Nichia Chemical Industry developed a variety of light intensity of more than 1 cd. Prior to this, there were no LEDs with high blue purity and practical light intensity. Therefore, a large-size display using LEDs cannot achieve full-color display.
The material of the blue LED uses a gallium nitride (GaN)-based semiconductor. In the past, blue LEDs were developed using zinc selenide (ZnSe) semiconductors. However, since the development of high-brightness blue LEDs using GaN-based semiconductors in December 1993, the mainstream of blue LEDs has become GaN-based. Semiconductor products.
The blue LED is configured such that an aluminum nitride (AlN) semiconductor layer and a GaN-based semiconductor layer are stacked on a surface of a sapphire or SiC substrate or the like. A structure in which a p-type GaN-based semiconductor layer and an n-type GaN-based semiconductor layer are overlapped is provided in a portion called an active layer and blue-emitting light.
The pn junction is the structure that must be used to make high-brightness LEDs. Among LEDs such as red, which use materials other than GaN, the pn junction is a mainstream structure long ago. Before the introduction of high-brightness blue LEDs in 1993, it was difficult to achieve pn junctions using GaN-based materials. The reason is that the formation of the n-type GaN-based semiconductor layer is relatively simple, but the fabrication of the p-type GaN-based semiconductor layer is difficult. After that, by using a multiple quantum well structure for the GaN-based semiconductor layer disposed between the p-type GaN-based semiconductor layer and the n-type GaN-based semiconductor layer, and further improving the quality of the GaN-based semiconductor layer, the light intensity is greatly improved.
The large investment in blue LEDs continues to rise, and there is a fear of oversupply
At present, LED backlights are rapidly spreading in the fields of LCD TVs, personal computers and liquid crystal displays. Most of the demand is white LEDs, and the blue LEDs on which they are based are starting to be under-supplied. To this end, not only LED professional manufacturers, but also the display manufacturers that buy LEDs have begun to expand the production of white LEDs and blue LEDs. For example, in addition to South Korea’s Samsung Electronics’ active investment in Samsung’s LED chips , LCD panel makers such as South Korea’s LG Display have also begun to strengthen LED production. The old LED professional manufacturers led by Nichia Chemical Industry are also actively investing. If the investment production equipment can run smoothly, it can eliminate the shortage of LED supply in one fell swoop, but it may also lead to oversupply due to overproduction.
Display Search's survey shows that the production capacity of blue LED chips for LED backlights produced by Samsung LED is 467 million/month in 2009, and will reach 1.33 billion/month in 2010 (annual production capacity) For 16 billion). In 2009, the MOCVD device (blue LED GaN-based semiconductor device) introduced by the company far exceeded 100 units. If the device is fully operational, it is estimated that the monthly output will reach about 2 billion chips.
In addition, Display Search also predicts that Nichia's production capacity of blue LED chips will increase from 1.33 billion/month in 2009 to 3.067 billion/month by strengthening production capacity. In addition, Taiwan's OptoTech, which is cooperating with Nichia's chemical industry, will increase its monthly production capacity by more than two times from 133 million in 2009 to 3 billion. Other manufacturers are also strengthening the production capacity of blue LED chips, so the overall equipment investment in the industry will exceed the 2010 LED chip demand (100 billion chips) estimated by Display Search.