| 摘要 |
PURPOSE:To form a practically sufficient scanning range and to display an object image on a TV monitor at a real time by forming acoustic/optical polarizing elements. CONSTITUTION:The polarizing surface ab of the 1st acoustic/optical polarizing element 3 is set up on the front focus F1 of a pre-group lens 4 of a relay lens 6. The back focus of the pre-group lens 4 coincides with the front focus of the post group lens 5. On the other hand, the polarizing surface cd of the 2nd acoustic/optical polarizing element 7 is set up on the back focus F2 of the post group lens 5. Consequently, the polarizing surfaces ab, cd are set up on optically conjugate positions respectively and made optically equivalent. Thus, troubles such as the shift of a polarizing point on the 2nd polarizing surface from the optical axis which is generated due to the shift of two polarizing surfaces in the optical axis direction which inevitably exists when two acoustic/optical polarizing elements are tightly arranged are removed and two acoustic/optical polarizing elements 3, 7 can be used under the most optically preferably condition.
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