Sony Corp. said Wednesday it has invested in U.S. artificial intelligence startup Cogitai, aiming to develop new AI technologies and release products using them within the next three years. Sony is believed to have obtained a roughly 20 percent stake in the company, founded in September by three AI researchers, in a move that could lead to the Japanese electronics giant's return to the robot business. Sony was an AI pioneer, known for producing robotic dog AIBO and humanoid QRIO featuring AI technologies. But it withdrew from the robot business in 2006 to improve profitability and restructure its consumer electronics business. The company has continued AI research itself, however, and its technologies, including face and speech recognitions, have been applied to other Sony products, such as digital cameras and smartphones.