| 摘要 |
PURPOSE:To provide a light source for a liquid crystal projection type projector presenting an optimum operating performance, by furnishing reflection mirror equipped with reflecting surfaces having two different radii of curvature, and thereby making light the surface irradiated and also improving the uniformity of illuminance. CONSTITUTION:As a curved surface the first reflecting surface is provided near the aperture of a reflection mirror 4 in the form of a surface of paraboloid of revolution or a surface of oblong ellipsoid of revolution 6 as approximation thereof, and in continuity to this curved surface, the second reflecting surface having a smaller flatness rate than the plane 6 is formed as a surface of ellipsoid of revolution 8. A glass bulb 3 is positioned so that a filament 2 lies near the focus f3 of the former named elliptical plane 6, and the primary focus of the latter named ellipsoidal surface 8 is located nearer the bottom of the mirror 4 than the focus f3. The edge of the plane 6 is positioned approx. perpendicular to the filament 2 so that the incidence angle theta of the light emitted thereby (approx. 60 deg. or below) does not enlarge which should cause drop of the reflection efficiency. Thereby the light quantity incident to a liquid crystal panel 10 is made uniform over its whole area, and the uniformity of the illuminance on the surface irradiated can be improved. |
