| 摘要 |
PROBLEM TO BE SOLVED: To prevent, by a simple configuration, a wavefront of video light from being disturbed by external foreign matter P; and to avoid degradation in the quality of a video to be observed, caused by foreign matter P. SOLUTION: The video display apparatus is provided with a protective substrate 32 for protecting the face 21b of an eyepiece prism 21, and a support member 33 for supporting the protective substrate 32. The protective substrate 32 is disposed via the face 21b of the eyepiece prism 21 and an air layer. This ensures the occurrence of a refractive index difference between two media sandwiching the face 21b. Thus, the protective substrate 32 prevents external foreign matter P from directly sticking to the surface 21b. Accordingly, video light guided inside the eyepiece prism 21 is surely and totally reflected by the face 21b, thereby preventing the wavefront of the video light from being disturbed by the foreign matter. Moreover, the support member 33 supports the protective substrate 32 in contact with the non-total reflection area 21b<SB>2</SB>of the face 21b. This prevents the support member 33 from interfering with the total reflection of video light in the total reflection area 21b<SB>1</SB>of the face 21b. COPYRIGHT: (C)2009,JPO&INPIT |
