| 摘要 |
PURPOSE:To enable realization of multistages of variable power projection with simple constitution by forming a small-diameter imaging element array which forms images of different magnifications in such a way that the array can be selectively and freely attachably and detachably exchanged to and from the main unit of a device. CONSTITUTION:An optical system 40 for exchange is disposed with an imaging element array 42 in an outside body 46 of a cylindrical shape by matching the longitudinal direction of the body 46 and the longitudinal direction of the array 42. The length of a reflecting member 45 formed to the rear end thereof is set to each of the magnifications of the array 42, for example, l1, l2, l3. Photosensors A, B, C of a reflection type are disposed in the main unit in accordance with said lengths. The image forming magnifications of the system 40 can be detected by detecting respectively the light reflected by the member 45. A slit slt attached with glass 41 for dust-proofing is longitudinally formed to the body 46 in the position opposite to the photodetecting surface of the array 42. |
