Patent ID: 6396639
Filing Date: 2002-05-28
Classification: G02B

Abstract:
A viewing optical system comprising:reflection type image display constructed and arranged to display an image by reflecting an illuminating light beam incident from a front side of a display surface for forming an image for observation; and an ocular optical system for leading said image to a pupil position where an observer's eyeball is to be placed, wherein said image display comprises: an illuminator; and an illuminating light guide optical system constructed and arranged to guide a light beam emitted from said illuminator so that said light beam can be applied to said display surface from a front side thereof; and wherein said ocular optical system includes a prism member, said prism member comprising: an entrance surface through which a display light beam reflected from said reflection type image display enters said prism member after passing through said illuminating light guide optical system; at least one reflecting surface reflecting the light beam in said prism member; and an exit surface through which the light beam exits from said prism member, wherein said at least one reflecting surface of said prism member is decentered with respect to an optical axis and has a rotationally asymmetric curved surface configuration that corrects decentration aberrations due to decentration of said at least one reflecting surface and gives a power to the light beam, and wherein a spacing between the entrance surface of said prism member and the display surface of said reflection type image display satisfies the following condition to lead said image to said pupil position: 0.6<L/H<3.1 where L is a distance between an image center position where the display surface of said reflection type image display intersects the optical axis and a position where the entrance surface of said prism member intersects the optical axis, and H is an image height of said reflection type image display which is a diagonal length in a case where the display surface is quadrangular.