| 摘要 |
PURPOSE: To reduce the power consumption of a convergence circuit by decreasing keystone distortion, to improve reliability by increasing luminance on a transparent screen and equally distributing the temperature on a face plate from its center and to almost equalize lightness on the left side and right side of the transparent screen concerning the three-tube projection type television. CONSTITUTION: Projection tubes 1R, 1G and 1B, for which a projection axis is made vertical to face plates 6R, 6G and 6B, are used and the left and right projection tubes 1R and 1B cross a transparent screen 5 at an inclination angleαwhile being offset just forΔL. Then, their image anglesβ1 andβ2 are made equal and the face plates 6R and 6B are arranged on a plane orthogonal to center lines 2Rs and 2Bs of lenses 2R and 2B while being inclined just at an angleα' on the condition of 1/m.tanα=tanα'. Then, images on the face plates 6R and 6G are adjusted so as to be formed at the center of a fluorescent screen and the prescribed amount of keystone distortion correction is applied by the convergence circuit.
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