| 摘要 |
PURPOSE:To efficiently make an incident light quantity transmit through, by superposing plural pieces of slab-shaped refractive index distribution type lenses of a focusing property, having a refractive index distribution in only one direction, along the direction of the refractive index distribution so that the refractive index distribution and the vertical surface contact, and the refractive index distribution becomes parallel to each other. CONSTITUTION:In the rectangular parallelopiped-shaped glass, the X direction and the Z direction have no refractive index gradient, only the Y direction has such a refractive index gradient as the refractive index decreases to a prescribed quantity from the center surface of the rectangular parallelopiped to the upper and lower directions, and the Z direction is taken in the optical axis, it can be taken greatly in length of the X direction as long as the manufacturing condition of a slab is allowed. Also, with respect to a light beam which has been made incident along the Z axis, the X direction has no lens effect at all, but in only the Y direction, an incident light transmits through as a sine wave. Accordingly, when length of the lens is adjusted to length of 3P.4 from P/2, an image distance and an object distance become equal in the Y direction, and an erect unmagnification real image can be formed.
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