| 摘要 |
FIELD: physics. ^ SUBSTANCE: one version of the invention provides a diffraction ophthalmic lens which can be, for example, an intraocular lens which includes an optical element having a front surface and a rear surface, where the optical element provides a long focus. The broken diffraction structure containing a collection of diffraction zones lies on at least one of said surfaces to provide near focus. Each zone is separated from the neighbouring zone by the boundary of a zone which causes optical delay in the incident light. Also, at least two successive boundaries of the zone have such a configuration where the difference between their corresponding phase delays for at least one wavelength of incident light is greater than approximately of the wavelength for directing part of the incident light to the position between the near and far foci. ^ EFFECT: high quality of the intermediate image without deterioration of near and far vision. ^ 36 cl, 8 dwg |
