| 摘要 |
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 image, and which is extremely small in size and light in weight and hence unlikely to cause the observer to be fatigued. The apparatus includes an image display device (6) and an optical system (5) for projecting an image displayed by the image display device (6) and for leading the projected image to an observer's eyeball (7). The optical system (5) includes a first optical element (3) filled with a medium having a refractive index larger than 1. The first optical element (3) has, in the sequence of backward ray tracing, a first surface (11) serving as both a refracting surface and an internally reflecting surface; a second surface (12) which is a reflecting surface decentered or tilted with respect to an observer's visual axis (2); and a third surface (13) which is a refracting surface closest to the image display device (6). The optical system (5) further includes a second optical element (4) provided between the observer's eyeball (7) and the first optical element (3) and having two refracting surfaces. Assuming that the focal length of the second optical element (4) is f2, and the focal length of the optical system (5) is fA, the condition of 0.01<fA/f2<0.3 is satisfied.
|
