| 摘要 |
PURPOSE:To suppress generation of stray light so that optical performance is enhanced and to increase the mechanical strength of lenses so that the handling characteristic of the lenses is improved by adhering and fixing semicircular cylindrical groove parts for placing the lenses to an array shape by a transparent adhesive agent. CONSTITUTION:The distributed index lenses 6 are pinched from above and below by two pieces of light absorptive members 9 provided with the semicircular cylindrical groove parts having the curvature nearly equal to the curvature of the lenses on the surfaces facing the lenses. Very small rugged surfaces 8 for effectively absorbing light are formed in the groove parts. The lenses 6 are adhered and fixed to the rugged surfaces 8 by means of the transparent adhesive agent 7. 90% of the light arriving at the outer circumferential surfaces of the lenses collides against the rugged surfaces 8 through the adhesive material 7 and is effectively absorbed by the same when n1<=n2 at the refractive index n1 in the outer circumferential part of the lenses and the refractive index n2 of the adhesive agent 7. The rest of the light repeats collision and absorption by Fresnel reflection and is thereby attenuated. The Fresnel reflection is zero at n1=n2.
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