| 摘要 |
PURPOSE:To enhance the efficiency of utilizing the display light from an image display means and to make the brightness of an outside field image adjustable including a shut off. CONSTITUTION:A liquid crystal display element 2 is so arranged that the direction of the polarized light of the light emitted from this liquid crystal display element 2 parallels with the incident surface on a polarization beams splitter(PBS) 5 arranged in front of an observer's eyes. The exit light from the liquid crystal display element 2 is thereby transmitted through the PBS 5, is passed through a quarter-wave plate 6 arranged on its exist side, is reflected by a concave mirror 3, is again passed through the quarter-wave plate and is made incident on the PBS 5. Since the light passes the quarter-wave plate 6 back and forth, the display light is mostly reflected by the PBS 5 and is made incident on the observer's eyes. The exit light from the liquid crystal display element 2 arrives at the observer's eyes with substantially no loss. The half of the external field light 4 is reflected by the PBS 5 and the remaining half arrives at the observer's eyes. |
