| 摘要 |
PURPOSE:To obtain an optical lens which has a large numerical aperture and whose lens gap is set with high precision by providing the 1st and 2nd optical transparent substrates with a semicylindrical part which has a different refractive index, superposing respective semicylindrical parts one over the other, and uniting the both into a cylindrical optical lens. CONSTITUTION:The optical transparent 20 and 22 have plural optical axes 24. Then, those substrates have their refractive indexes distributed in a cylindrical shape 26 in proportion to nearly the square of distance from each optical axis. In this case, the substrates are stacked so that their optical axes 24 are aligned to each other. When parallel luminous flux 28 is made incident on an end surface of this lens, the luminous flux is converged. This lens is normally called a convergence type fiber lens and provides lens effect on the same principle. This lens is usable as a cylindrical lens having its optical axis at right angles to the optical axis 24. Further, the refractive index is distributed increasing almost in proportion to the square of distance from the optical axis to form a concave lens. |
