| 摘要 |
PURPOSE:To prevent the image distortion by the deformation of a dichroic mirror by its own weight by forming the strain-component of a reflection surface by its own weight of the dichroic mirror for synthesis as a recessed or projecting surface according to the direction for the perpendicular direction of the reflection surface. CONSTITUTION:The light from a light source 1 is separated to three primary colors and after these colors are modulated by image signals, the light rays of the respective primary colors are synthesized by the dichroic mirror 6 for synthesis disposed diagonally with the perpendicular direction. The synthesized light is projected into a screen by a projecting lens 7. The rear surface of the dichroic mirror 6 for synthesis is previously chipped to form a recessed part when the incident light reflects on the rear surface of the dichroic mirror 6 for synthesis. The front surface is bulged to form the projecting part so that the reflection surface is flattened at the time of packaging if the incident light reflects on the upper surface. The max. distortion quantity Hmm by its own weight of the dichroic mirror 6 for synthesis is given by equation I and the arc projecting or recessed shape of radius of curvature Rmm given by equation II is formed. In the equations, T, L denote the thickness of the dichroic mirror and the length of the fulcrum thereof. |
