In 1968, after announcing the invention of SELFOC™, the company had continued research into possible medical applications. Then, in 1973, it entered into a business tie-up with Olympus Optical Co., Ltd. (now Olympus Corporation) with a focus on medical needle endoscopes, further accelerating development in this field. In November 1975, Opnotech Co., Ltd. was formed as a joint venture between the two companies, and production of image bundles began as a result. An image bundle refers to the bundle of optical fibers that relay images from medical endoscopes. They are used in almost all endoscopes manufactured by Olympus Optical Co., Ltd., which has a 90% share of the global market.