Optical path splitting element and image display apparatus using the same

An image display apparatus comprising:

• an optical path splitting element for splitting a light beam from a single object into at least two optical paths;
• an image display device disposed at a position of said object;
• and
• an ocular optical system having at least a positive power to project the at least two optical paths split by said optical path splitting element near an eyeball of an observer;
• wherein said optical path splitting element has a prism member formed from a medium having a refractive index (n) larger than 1 (n>1), said prism member having:
• an entrance surface through which the light beam from said object enters said prism member;
• at least one reflecting surface reflecting the light beam within said prism member;
• and
• an exit surface through which the light beam exits said prism member;
• said prism member having at least one rotationally asymmetric surface;
• wherein at least one optical functional surface of said prism member is a discontinuous surface formed from at least two surfaces adjacent to each other, and other optical functional surfaces of said prism member are common to said at least two optical paths.