JPS57141612A - Method and device for variable magnification of compound eye image forming element - Google Patents

Abstract

PURPOSE:To set image magnification to a desired value by a simple means by arranging a variable magnification optical element shifted laterally in front of a compound eye image forming element, and varying their interval synchronously with the magnification variating operation of the optical element. CONSTITUTION:In front of a compound eye image forming element 14 for forming an erecting image of nonmagmification, a laterally shifted variable magnification optical element 13 consisting of lens elements 11 and 12 is arranged. When the focal length of the optical element 13 is made greater than a distance L1 between the optical element 13 and an object by shifting the lenses 11 and 12 laterally, an erecting virtual image 17 of the object 15 while its size is increased by the optical element 13 from h1 to h2 is formed at a distance L2 from the element 13. Then, when the compound eye image forming element 14 and an image forming surface 16 are moved forth in one body by a distance L2-L1 to position the virtual image 17 on the object surface of the compound eye image forming element 14, the erecting virtual image 17 of nonmagnification is formed on the image forming surface 16. Thus, image forming magnification is set to a desired value by the simple means.