JPH0145892B2 - - Google Patents

Claims (1)

[Scope of Claims] 1. A rotationally symmetrical front convex surface having an aspherical effective part, a following transition part, and a peripheral zone;
In a ophthalmic lens with a large positive refractive index, which has a concave surface on the eye side forming a supporting edge together with a peripheral zone, the vertical height z of a point in a predetermined range in the vicinity of the apex O is equal to the effective part W of the apex. The vertical height of a point that is outside the above range of the effective part and is greater than the vertical height of a point that has the same radius of curvature and is in contact with the effective part at the apex and is the same distance h from the optical axis A. A spectacle lens characterized in that a height z is smaller than a point on a spherical surface that is the same distance h from an optical axis A. 2 The distance in the optical axis direction (vertical height) z between one point of the effective portion W and the vertex O of the front surface D1 is calculated by the following formula (in the formula,
h represents the distance between the above point and the optical axis A, and C
is given by (depending on the desired refraction value of the front surface at the vertex), The aspherical coefficients K, I ₃ , I ₄ , I ₅ , I ₆ are determined by the following formula (where ΔR is the refraction value error, i.e., the effective part of the refraction value at the vertex at the above point) over the entire range of viewing angles. 2. The eyeglass lens according to claim 1, wherein the eyeglass lens is selected so that |ΔR|+|ΔS|=minimal (representing the deviation of the refractive value and ΔS representing astigmatism) is satisfied. 3 The distance in the optical axis direction (vertical height) z between one point of the effective portion W and the vertex O of the front surface D1 is determined by the following formula (in the formula,
h represents the distance between the above point and the optical axis A, and C
is given by (depending on the desired refraction value of the front surface at the vertex), The eyeglasses according to claim 1, wherein the aspheric coefficients K, I ₃ , I ₄ , I ₅ , and I ₆ are selected so that the visual acuity is maximized in the entire range of viewing angles. lens. 4 Visual acuity V is calculated using the following formula (where ΔR=min(|S|,
|T|), ΔS=||S|−|T||, S represents the sagittal refraction value error, i.e. the deviation of the sagittal refraction value at one point on the effective surface with respect to the refraction value at the apex; T represents the tangential refraction value error) V=2 ^-2