| 摘要 |
An ophthalmic contact lens containing more than one phase plate within its optic zone, including contact lens, especially of a Cohen lens design, which possesses phase plate optics within its optic zone that progressively shift the intensity of light focussed by bifocal phase plates between the diffractive focal powers by utilizing echelettes in the phase plates of varying depths and heights which are cooperatively aligned relative to the lens base curve surface that they openly face. |
