METHOD FOR DESIGNING LENS FOR EYEGLASSES AND LENS FOR GLASSES

• Main Author: MIYAJIMA YASUSHI
• Format: Patent
• Language: English; Japanese
• Published: 27.06.2019
• Subjects: CONTACT LENSES; OPTICS; PHYSICS; SPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURESAS SPECTACLES

To provide a method for designing a lens for eyeglasses where a front lens surface is set with a radius of curvature of 150 mm or less, and with which it is possible to obtain a greater depth of field extension effect in a region close to lens periphery than possible before.SOLUTION: A combination is made from an average power stabilization component, expressed by Br+Cr+Dr+Er(where, r is the distance from an axis z, and B, C, D, E are constants), the axis z representing an axis in the longitudinal direction passing through the optical center of a lens, which suppresses a change of average power in a lens plane, a depth of field extension component expressed by Ar(where, A is a constant), which extends the depth of field, and further a camber angle correction component, expressed on a plurality of divided lines radially extending from the optical center by F(θ)r+G(θ)r+H(θ)r+I(θ)r(where, F(θ), G(θ), H(θ), I(θ) are constants, θ is an angle from an axis x orthogonal to the axis z), which works so as to cancel out a change of average power that occurs when the optical axis of the lens is titled at a prescribed camber angle, the combination being added to the z coordinate value of rear surface 2 of the lens that is determined on the basis of prescribed power.SELECTED DRAWING: Figure 11 【課題】レンズ周縁に近い領域において従来以上の被写界深度延長効果を得ることが可能な、レンズ前面が曲率半径１５０ｍｍ以下で設定されている眼鏡用レンズの設計方法を提供する。【解決手段】レンズの光学中心を通る前後方向の軸をｚ軸としたとき、Bｒ4+Cｒ6+Dｒ8+Eｒ10（但し、ｒはｚ軸からの距離、B,C,D,Eは定数）で表され、レンズ面内の平均度数の変動を抑制する平均度数安定化成分と、Aｒ3（但し、Aは定数）で表され、被写界深度を延長させる被写界深度延長成分と、更には、光学中心から放射状に延びる複数の分割線上において、F(θ)ｒ4+G(θ)ｒ6+H(θ)ｒ8+I(θ)ｒ10（但し、F(θ),G(θ),H(θ),I(θ)は定数、θは前記ｚ軸と直交するｘ軸からの角度）で表され、レンズの光軸を所定のそり角で傾けた際に生じる平均度数の変化を打ち消すように働くそり角補正成分と、を組み合わせ、処方度数に基づいて決定されるレンズの後面２のｚ座標値に付加する。【選択図】 図１１