| 摘要 |
The base of the microfiche reader has a duct at the rear enclosing the fan which delivers cooling air from the forward facing duct at the right of the base. This latter duct receives an optical drawer in which the lamp, heat absorbing glass, condensing lens system, and a first mirror are mounted. The lamp is mounted in a carrier which is adjustable relative to the condensing lens and projection stage to allow the lamp position to be matched to the magnification power of the projection lens which drops in the lens board above the fiche carrier and adjacent the front of the reader for easy focusing access. The upwardly projected image then strikes a second mirror and is reflected back to third and fourth mirrors mounted at 90 DEG to each other for movement fore and aft for varying the projection distance (and, hence, image size) to the screen. The screen can be horizontal or vertical. The third and fourth mirror assembly is moved only one half the effective distance change and this conserves depth of the reader. The fiche carrier supports the fiche between two glass plates in a plane parallel, above, and to one side of the reference grid plane and is provided with a downwardly inclined, pencil-like pointer which can be grasped by the operator for very "natural" selection of the desired grid reference causing corresponding movement of the fiche carrier to position the selected fiche in the projection position.
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