| 摘要 |
PURPOSE:To compensate aberrations of a projection lens excellently by providing a step to the video-tube side surface of the lens element of the projection lens which is closest to the video tube, and making a transparent material thin at the center part and thick at the peripheral part. CONSTITUTION:When a frame body 32 is assembled, the frame body needs to contact a face plate 22 and a collar 25 so that the transparent material which is liquid does not leak, so the frame body 22 is fixed to the face plate 22 and collar 25 with an adhesive, etc. Consequently, the step part 27 is constituted at the periphery of the lens surface 26 of the lens element 24 on the side of the video tube 21 and the transparent material 36 is thin at the center part 37 and thick at the peripheral part 38. Consequently, aberrations of the projection lens are compensated excellently and the frame body 32 is thick enough can be arranged between the collar 25 of the lens element and the face plate 22.
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