COMPOSITE DISPLAY APPARATUS AND HEAD MOUNTED DISPLAY SYSTEM USING THE SAME

A composite display apparatus keeps both optical density of display images formed by a display means and shutter speed of cameras such as a CCD in an optimum state relative to the external world light (see-through light), even in environments where the quantity of see-through light varies widely. The composite display apparatus includes a display optical system for guiding a light beam from a display means to the eyeballs of an observer; an image-pickup optical system for allowing an external light beam to form an image on an image-pickup means; and an optical path separating means provided in an optical path for allowing an ocular optical axis of the light beam of the display optical system entering the eyeballs of the observer, or an imaginary ocular optical axis which is an extension of the ocular optical axis, and an external world optical axis of the light beam entering the image-pickup optical system to substantially coincide.