When ASD was fist introduced in the 1980s, the Xenon lamp was used as the light source taking advantage of the bright and full-spectrum light to achieve very high sensitivity smoke detection. However, due to the high maintenance cost of Xenon lamp and also the development of laser technology, the ASD developed in the 1990s tended to use infra-red laser as the light source. Although the laser offered improved maintenance, the expense is reduced sensitivity to small particles due to the long wavelength of infra-red. In the 2000s, the significant progress of high power bright LEDs along with the invention of blue LED makes high power blue LED the perfect light source for the ASD. Compared to Xenon lamp and infra-red laser, the high power blue LED used in AVA's Aspirating Smoke Detector not only maintain the ability to detect small particles due to the short wavelength of blue light, it also provides super bright light, large volume detection, wider temperature range and long life time.