A flash device for a camera having a light emitting window of rectangular shape oriented so that the long side of the window is nearly perpendicular to a long side of the film format in the camera. An optical panel in the light emitting window is constructed in such a way as to satisfy the following...http://www.google.com.tw/patents/US4702581?utm_source=gb-gplus-share專利 US4702581 - Flash device for camera
