In the last few years, LED manufacturers positively develop high-brightness LED chips, treating the corresponding market as full of potentials and opportunities. The basic concept is enabling LEDs to work under high current to generate brighter light. According to current specifications, a LED chip with an area of 30um2 can withstand the maximum current of 30mA, which cannot meet the requirements of having LEDs generate larger luminance. In accordance with the expectation of the market, a LED chip with an area of 1mm2 can withstand the maximum current of 350mA. So that single-chip LEDs could generate higher internal quantum efficiency. Supposed the driver current is 3 volts, after calculation, there will be nearly 1W power that flow into LED chips every second.
However, simply increasing the current cannot solve the problem fundamentally. Normally, about 3/4 inflow electricity will be wasted and convert into thermal energy. In another word, only 1/4 (0.25W) electrical energy will convert into optical energy. Troubles caused by the thermal effect usually exerted bad influence on LED lighting applications. LEDs will change the wavelength with the variation working temperature. Working in high temperature for a long time will reduce the luminous efficiency and CRI.
Theoretically, if the luminous efficiency of blue-ray LED chips can reach up to 360lm/W, along with high-level packing capabilities, it is not really difficult to obtain a 100lm/W white-ray output. It would not be a big issue with today’s LED technology. Many large international LED manufacturers have successfully developed high-brightness blue-ray LED chips, including CREE and Nichia. Now the really bottleneck is how effectively reduce the external quantum efficiency loss, which will test the ability of packaging industry.
On the other hand, the thermal effect caused by the increasing of input current is a very serious problem that needs to be solved urgently. Basically, reducing thermal impedance and improving heat dissipation is a generally direction for designers and producers. The current solution is reducing the thermal impedance of LED Panel Light chips, limiting the thermal impedance of control modules and printed circuit boards, increasing the heat dissipation effect of LEDs. Typically, manufacturers tend to choose materials with lower thermal impedance and good thermal conductivity. But in the mean time, size and weight are also two important factors that need to be taken into account.