PROJECTING LENS

PURPOSE:To obtain always good projected images even if a projecting screen surface has any curvature by providing a spacing adjusting means which changes the air spacing of at least one lens group in a lens system according to the average curvature of the projecting screen surface to be projected wi...

Ausführliche Beschreibung

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Bibliographische Detailangaben
1. Verfasser: TSUJI SADAHIKO
Format: Patent
Sprache:eng
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Beschreibung
Zusammenfassung:PURPOSE:To obtain always good projected images even if a projecting screen surface has any curvature by providing a spacing adjusting means which changes the air spacing of at least one lens group in a lens system according to the average curvature of the projecting screen surface to be projected with the images. CONSTITUTION:The projecting lens 1 has the two lens groups; a front group 2 and a rear group 3. An average curvature of field which is one of optical characteristics is set at a prescribed value by providing the spacing adjusting means 11 and changing the air spacing between the front group 2 and rear group 3 of the projecting lens 1. A part of the lens groups in the lens system is moved on the optical axis in correspondence to the curvature of the projecting screen surface in such a manner to change the air spacing between the lens groups, by which the curvature of the average image plane is changed and is matched with the curvature of the projecting screen surface. The observation of the good projected images is thus possible over the entire part of the projecting screen surface even if the projecting screen having any curvature is used.