Automatic film winding/rewinding device for prevention of film exposure to light and related control method

摘要

An automatic film winding/rewinding device and related control method for prevention of film exposure to light due to leaving non-rewound film in a camera for a long time or due to a operator mistakingly opening the back cover of the camera. In operation, the device automatically rewinds the film when the camera power switch is turned off for a long period of time. The device winds the film back to the next frame position when the camera is turned on so that the remaining film is fully utilized. Further, the device allows the film to be rewound if the back cover is opened. The device includes a film number sensor for sensing the perforation number of the film as the film is wound and produces an electric signal corresponding to the number of the perforation of the film.