| 摘要 |
PROBLEM TO BE SOLVED: To provide a composite optical element having an objective lens function of three wavelength compatibility and a function to correct spherical aberration with a high utilization efficiency of light and easy to process.SOLUTION: The composite optical element includes: a single lens substrate having a curved surface on at least one surface acting as a lens; and a resin layer laminated thereover. On the interface between the single lens substrate and the resin layer, a first phase-step surface which has a step-like cross-section formed with steps disposed concentrically around the optical axis. On the other surface of the resin layer, a second phase-step surface which has a step-like cross-section with steps formed disposed concentrically around the optical axis. The steps constituting the first phase-step surface and the steps constituting the second phase-step surface are disposed alternately. The optical action by the first phase-step surface and the second phase-step surface is an action of a convex lens with respect to the light of wavelength λ1, and an action of a concave lens with respect to the light of wavelength λ2 and the light of wavelength λ3. |
