| 摘要 |
PURPOSE:To vary a spot shape by using simple constitution in two optical compensation type zoom lens systems by providing a zooming function only in a plane and flank which cross each other at right angles. CONSTITUTION:A laser beam L which is made incident as parallel luminous flux varies in image formation beam diameter as the focal length varies in planes of optical correction type beam lens systems 10-12. Further, light passes through the lens 12 passes through optical compensation type zoom lenses 13-15 with the zooming function only in the flank without any variation to form its image. Further, the beam L passes through the lens systems 10-12 without any variation in the flank and varies in focal length and image formation beam diameter by the lens systems 13-15. Therefore, when the two lens systems are varied continuously in focal length, the image formation beam diameter varies continuously. Consequently, the spot shape can be varied by the simple constitution.
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