June 20, 2017: Over the past few years, thin pitch indoor LED displays have emerged in the market. However, there is one immense challenge that the industry is continuously facing and that is, miniaturizing LED appropriate for display smaller than 100-inch, according to an Epistar chief spokesperson.
Thin fine pitch indoor LED displays consists of numerous advantages in the 100-150 inch display variety, however the least amount size of LED package made of extensively -used PLCC, plastic leaded chip carrier, is restricted to 0505.It becomes very expensive to further miniaturize the LED package and to attain the appeal of the consistency of wavelength for displays, which are smaller than 100-inch, said the spokesperson.
Quantum dot solution
In order to get rid of such technical blockage, Epistar has opted for a solution that sprays quantum dots (QD) onto CSP LEDs. With the help of QD enhanced CSP LEDs, the company has taken benefit of the wire-bonding free chips to create LED packages smaller than 0.5mm, miniaturizing package sizes down to 0303 and 0202.
Furthermore, the consequential indoor fine pitch QD LED displays may be smaller than 60-inch, the spokesperson added. The benefit of the QD solution is that it enhances the consistency of blue and green discharge. In addition, it solves the matter from producing costly AlInGaP (red) LED flip chips and, they are more efficient in blue and green range in comparison with traditional LEDs, according to the spokesperson.
Blue and green LEDs are grown on sapphire substrates, which is transparent to let light come through. However, red LEDs are gown on opaque GaAs substrates and, they need to be transferred to glass or another transparent substrates with the purpose of creating flip chips, added the spokesperson.
The wavelength disparity of Epistar’s mass manufactured blue LED chips is 5 to 12nm, which is still far from the objective of achieving the aim of 3 to 4nm in appeal of fine pitch display. In addition, it is very expensive to alter red LED chips from vertical structure to flip chip which is essential in smaller LED displays.