| 摘要 |
PURPOSE:To obtain images of luminance distributions which are good for practicability over a relatively wide effective visual field range with respect to a transmission type screen for projectors provided with lentikular lens having a semicircular shape. CONSTITUTION:The sectional shape of semicircular lenses is selected to the curve between the threshold curves Z1 and Z2 expressed by formulae. In the case of the curve Z2, the screen gain is roughly flat in the range of -18-+18 deg. directional angles and in the case of the curve Z1, the screen gain is roughly flat in the range of -32-+32 deg. directional angles. In both cases, luminance can be maintained relatively large. If the sectional shape of the semicircular lenses is selected at the curve between the curves Z1 and Z2, the characteristics of the screen gain are kept within the range between said curves, and the screen having good luminance distributions is obtained surely by selecting the sectional shape suitably. |
