An optical projection system includes an image generation element, a projection lens set for receiving an image from the image generation element, refracting the image and projecting the image out, and a reflector for reflecting the image from the projection lens set and projecting the image to a screen. The first and second ring lasers are so positioned as to be mutually independent optically. The request may be a hypertext transfer protocol request from a web browser. A second adjusting operation member adjusts a triggering displacement at which the raising and lowering displacement is transmitted to the clutch lever as the disengaging displacement.