Title:
ASPHERIC SPECTACLE LENS
Document Type and Number:
Japanese Patent JP3892702
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide an aspheric spectacle lens which makes it possible to obtain good performance even for another prescription when a prism prescription for phoria correction is included.
SOLUTION: An outer surface 2 of the aspheric spectacle lens 1 is a spherical surface and an inner surface 3 thereof is a rotationally asymmetric aspherical surface. The normal of the inner surface 3 erected at a frame insertion reference point 4 is defined as a z2 axis, a prism vertex direction within the plane perpendicular to the z axis inclusive of a point where the z2 axis intersects with the inner surface 3 as a y2 axis and the direction orthogonal with the y2 axis and z2 axis in a left-hand coordinate system as an x2 axis. The inner surface 3 has no inclination with an x2-y2 plane and the outer surface 2 inclines with the x2-y2 plane. When the curvature at a distance h [mm] from the z2 axis of a line of intersection of the plane forming an angle θ [degree] with the x2 axis inclusive of the z2 axis and the inner surface 3 is expressed as C (h, θ), the conditions C2(h, θ+180)-C2(h, θ)>0 are satisfied within the range satisfying 10≤h≤20, 30≤θ≤150.
Inventors:
Moriyasu Shirayanagi
Application Number:
JP2001318493A
Publication Date:
March 14, 2007
Filing Date:
October 16, 2001
Export Citation:
Assignee:
Pentax Co., Ltd.
International Classes:
G02C7/02; C01B13/11; G01N21/88; G02B13/00; G02B13/18; (IPC1-7): G02C7/02; G02B13/00; G02B13/18
Domestic Patent References:
| JP10078566A | ||||
| JP10206805A | ||||
| JP11002785A |
Attorney, Agent or Firm:
Shuhei Matsuoka