Panasonic has developed a blue violet semiconductor laser with higher optical output power for lamp, industrial lighting and laser processing machine. The oscillation wavelength is 405nm, and it can continuously oscillate for 4.5w at the working temperature of 60 ℃. According to Panasonic, this optical output power is 1.5 times of the original. In terms of efficiency, WPE (the ratio of optical output power to input power) is 33%. Panasonic aims to make the product practical by 2019.
In order to improve the optical output power, two main measures are taken. One is the cooling channel is formed on both sides of the laser element. The original is only in the single side (below) to form a heat channel. The thermal resistance is reduced from 10.5k/w to 6.6k/w by double-sided heat dissipation.
Another measure is to use AlN (aluminum smothering) on the "heat sink" used as the upper surface cooling channel. The thermal conductivity of AlN is high, and the coefficient of thermal expansion is similar to that of GaN semiconductor, which makes AlN easy to restrain thermal stress. When the difference of thermal expansion coefficient is large, it will be affected by the temperature change when the laser element works, and the laser element is easy to produce crystal defects.
Although it has the advantages of high resistance. However, Panasonic solved this problem by forming a through hole. (reporter: Gen Jinzhen)