An image display apparatus which enables observation of a clear image at a wide field angle with substantially no reduction in the brightness of the observation image, and which is extremely small in size and light in weight and hence unlikely to cause the observer to be fatigued. The image display...http://www.google.com/patents/US5699194?utm_source=gb-gplus-sharePatent US5699194 - Image display apparatus comprising an internally reflecting ocular optical system 
