Title:
SPECTACLE LENS
Document Type and Number:
Japanese Patent JP3853849
Kind Code:
B2
Abstract:
PURPOSE: To obtain a wide visual field from an intermediate distance to the extreme vicinity by specifying a relation between the refracting power of spectacle lenses at a fitting point and the far sight refracting power of the spectacle lenses.
CONSTITUTION: This spectacle lens has a fitting point O between a starting point P and end point Q of a progressing zone. The average gradient of the admission diopter from the start point P of the progressive zone near to the fitting point O and the average gradient of the admission diopter from near the fitting point O to the end point Q of the progressive zone are different. In addition, the refracting power of the spectacle lens is so determined that the relation 0.3<FP-DP<1.0 (unit; diopter) holds when the refracting power of the spectacle lens at the fitting point O is defined as FP diopter and the far sight refracting power of the spectacle as DP diopter. Then, the gradient from P to O and the position of FP are kept constant regardless of the admission diopter. The refracting power changes progressively to the near sight prescription of a user by the admission diopter.
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Inventors:
Hiroyuki Mukaiyama
Isamu Yukimasa
Isamu Yukimasa
Application Number:
JP30943993A
Publication Date:
December 06, 2006
Filing Date:
December 09, 1993
Export Citation:
Assignee:
Seiko Epson Corporation
International Classes:
G02C7/06; (IPC1-7): G02C7/06
Domestic Patent References:
| JP1221722A | ||||
| JP6210617A |
Attorney, Agent or Firm:
Hideo Tsukamoto