Answer
Blue is the primary color emitted by Hiroshi Amano's LEDs. Amano's groundbreaking work in the 1980s and 1990s led to the development of efficient blue LEDs, which were previously a significant challenge in the field of optoelectronics. The blue LEDs enabled the creation of white LEDs, which have revolutionized lighting technology and are now widely used in various applications, including general lighting, displays, and automotive lighting.