A display device includes a pixel array portion and a driving portion for driving the pixel array portion. An obstacle determination process section is provided which receives information from a sensor which detects an obstacle, receives terrain information of the position of the host vehicle from a navigation device, and determines the presence of the obstacle when a predetermined condition is satisfied after the sensor detects the obstacle. Each of the attachments forms part of the barrel, and when used with the preferred present shortened barrel, a so-called standard-length drier is provided which provides the additional benefits of the respective attachments, without being overly long so as to be cumbersome during use.