20120069432 | OPTICAL DEVICE FOR COUPLING TO A CAMERA LENS TO FORM A VISUAL OBSERVATION SYSTEM - An optical device is adapted for coupling to a camera lens so as to form a visual observation system. The optical device includes a housing, a connecting unit disposed at the housing, a first lens set disposed in the housing and having a negative optical power, a prism unit located at an image side of the first lens set in the housing, and a second lens set located at an image side of the prism unit in the housing and having a positive optical power. The connecting unit includes a camera lens bayonet for connecting to the camera lens. The prism unit has a light-entrance surface and a light-exit surface. An image formed by light beams exiting the light-exit surface is erected with respect to an inverted image formed by light beams entering the light-entrance surface. | 03-22-2012 |