We demonstrate a new endoscope system for laparoscopic surgery that provides two different views simultaneously. One is a 'wide view' and the other is an 'enlarged view' derived from the wide view with an optical image-shifting mechanism. By using this endoscope, surgeons can observe a surgical area as an enlarged view without moving or rotating the endoscope. Moreover, the wide view is useful for examining the outside of a surgical area. They can move the enlarged view within the area of the wide view by using the image-shifting mechanism. This system consists of a rigid scope and a 'zoom unit.' The rigid scope includes a set of optical lenses for the wide view angle (120 degrees) and light-guide fibers built in for illumination. These fibers are connected to a light source directly. The zoom unit includes imaging optical elements and two CCD cameras. In the zoom unit, an image provided by the rigid scope is divided into two ways by a half-mirror. One image is captured by the first CCD camera with relay lenses for a wide view. The other passes through a Porro prism (II), which is used to shift the enlarged view vertically and horizontally, and zoom lenses with a three variable power. Then, the image is captured by the second CCD camera for an enlarged view. A working distance between the tip of the rigid scope and the surface of viscera is 100mm that is sufficient for surgical operation.
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