METHOD OF MANUFACTURING MULTIFOCAL LENS AND MULTIFOCAL LENS

Abstract

A multifocal lens includes a group including M layered lenses. M-kinds (M is an integer of two or more) of lens materials having glass deformation point temperatures of At1, At2, . . . , AtM, are used and diluted by a heat press method. A contact surface of an N−1th lens (N is an arbitrary integer of two or more and M or less) contacted with an Nth lens is a concave face, a contact surface of the Nth lens contacted with the N−1th lens is a convex face. The glass deformation point temperatures have a relation of AtN-1>AtN.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements.

FIG. 1 illustrates the structure of a multifocal lens according to Embodiment 1 of the invention.

FIG. 2 illustrates a step of forming the first lens (step of placing the first lens material) in Embodiment 1.

FIG. 3 illustrates a step of forming the first lens (heat pressing) in Embodiment 1.

FIG. 4 illustrates a step of forming the second lens (step of placing the second lens material) in Embodiment 1.

FIG. 5 illustrates a step of forming the second lens (heat pressing) in Embodiment 1.

FIG. 6 illustrates a step of forming the third lens (step of placing the third lens material) in Embodiment 1.

FIG. 7 illustrates a step of forming the third lens (heat pressing) in Embodiment 1.

FIG. 8 illustrates the structure of a multifocal lens in Embodiment 2 of the invention.

FIG. 9 illustrates a step of forming the second lens (step of placing the second lens material) in Embodiment 2.

FIG. 10(A) illustrates the structure of a multifocal lens in Embodiment 3 of the invention.

FIG. 10(B) illustrates the structure of a multifocal lens in Embodiment 3 of the invention.

FIG. 11(A) illustrates a step of forming the second lens (step of placing the second lens material) in Embodiment 3.

FIG. 11(B) illustrates a step of forming the second lens (step of placing the second lens material) in Embodiment 3.

FIG. 12 is a schematic cross-sectional view illustrating the structure of a multifocal lens according to Embodiment 4 of the invention.

FIG. 13 is a schematic cross-sectional view illustrating lens material placed on a formation surface of a lower metal mold.

FIG. 14 is a schematic cross-sectional view illustrating lens material pressed between a lower metal mold and an upper metal mold.

FIG. 15 is a schematic cross-sectional view illustrating the second lens material placed on the first lens.

FIG. 16 is a schematic cross-sectional view illustrating the second lens material pressed between a lower metal mold and an upper metal mold.

FIG. 17 is a schematic cross-sectional view illustrating a multifocal lens taken out of a metal mold.

FIG. 18(A) is a schematic cross-sectional view illustrating a multifocal lens according to Embodiment 5 of the invention.

FIG. 18(B) is a top view of the multifocal lens according to Embodiment 5 of the invention.

FIG. 19 is a schematic cross-sectional view illustrating lens material placed on a formation surface of a lower metal mold.

FIG. 20 is a schematic cross-sectional view illustrating lens material pressed between a lower metal mold and an upper metal mold.

FIG. 21 is a schematic cross-sectional view illustrating the second lens material placed on the first lens.

FIG. 22 is a schematic cross-sectional view illustrating the second lens material pressed between a lower metal mold and an upper metal mold.

FIG. 23 is a schematic cross-sectional view illustrating a multifocal lens according to Embodiment 6 of the invention.

FIG. 24(A) is a schematic cross-sectional view illustrating a multifocal lens according to Embodiment 7 of the invention.

FIG. 24(B) is a top view illustrating the multifocal lens according to Embodiment 7 of the invention.

FIG. 25 is a schematic cross-sectional view illustrating the second lens material placed on the first lens.

FIG. 26 is a schematic cross-sectional view illustrating a multifocal lens according to Embodiment 8 of the invention.

FIG. 27(A) is a schematic cross-sectional view illustrating lens material placed on a formation surface of a lower metal mold.

FIG. 27(B) is an expanded cross-sectional view of an upper metal mold.

FIG. 28(A) is a schematic cross-sectional view illustrating the first lens pressed between a lower metal mold and an upper metal mold.

FIG. 28(B) is an expanded cross-sectional view of the first lens of FIG. 28(A).

FIG. 29(A) is a schematic cross-sectional view illustrating when an upper metal mold is removed after the formation of the first lens.

FIG. 29(B) is a schematic top view of FIG. 29(A).

FIG. 29(C) is a partial expanded cross-sectional view of the first lens shown in FIG. 29(A).

FIG. 30 is a schematic cross-sectional view illustrating a multifocal lens according to Embodiment 9 of the invention.

FIG. 31 is a schematic cross-sectional view illustrating a step of forming the first lens.

FIG. 32 is a schematic cross-sectional view illustrating modification of Embodiment 9.

FIG. 33(A) is schematic cross-sectional view illustrating a modification of Embodiment 9.

FIG. 33(B) is the top view of the modification of Embodiment 9.

FIG. 34 is a schematic cross-sectional view illustrating a multifocal lens according to Embodiment 9 of the invention.

FIG. 35 illustrates the structure of a conventional multifocal lens.

Claims

1. A multifocal lens comprising a group including M layered lenses, wherein M-kinds (M is an integer of two or more) of lens materials having glass deformation point temperatures of At1, At2, . . . , AtM, are used and diluted by a heat press method,wherein a contact surface of an N−1th lens (N is an arbitrary integer of two or more and M or less) contacted with an Nth lens is a concave face, a contact surface of the Nth lens contacted with the N−1th lens is a convex face, andwherein the glass deformation point temperatures have a relation of AtN-1>AtN.

2. A method of manufacturing a multifocal lens that includes a group of two layered lenses, comprising a) forming a first lens by diluting a first lens material having a glass deformation point temperature At1;b) forming a second lens by diluting a second lens material having a glass deformation point temperature At2 (At1>At2) while using the first lens as a part of a molding die, andc) bonding the second lens to the first lens simultaneously with step b) so that a contact surface of the first lens contacting with the second lens is a concave face and a contact surface of the second lens contacting with first lens is a convex face.

3. A method of manufacturing a multifocal lens that includes a group of three layered lenses, comprising: a) forming a first lens by diluting a first lens material having the glass deformation point temperature At1 with heat pressing;b) forming a second lens by diluting a second lens material having a glass deformation point temperature At2 (At1>At2) with heat pressing while using the first lens as a part of a molding die;c) bonding the second lens to the first lens simultaneously with step b)d) forming a third lens by diluting a third lens material having a glass deformation point temperature At3 (At1>At2>At3) with heat pressing while using the first lens and/or the second lens as a part of a molding die; ande) bonding the third lens to the first lens and/or the second lens simultaneously with step d).

4. The method of manufacturing a multifocal lens according to claim 3, further comprising: f) forming one or more concave sections at an upper surface of the first lens; andg) placing the second lens material on the concave sections.

5. The method of manufacturing a multifocal lens according to claim 4, wherein an upper surface of the first lens other than the concave sections is formed as a concave face;an upper surface of the second lens is formed to be a curved surface continuous from the concave faces of the first lens; andthe third lens material is placed on an upper surface of the continuous curved surface composed of the concave faces of the first lens and the upper part of the second lens.

6. The method of manufacturing a multifocal lens according to claims 3, wherein step d) further comprises. d′) forming a reference surface having at least two different diameters so that an outer periphery of the multifocal lens is positioned at a portion having a stepped shape to which the lens is-attached;d″) making a diameter of the second lens smaller than a diameter of the first lens and a diameter of the third lens; andd′″) adjusting the optical axis of the third lens to be the same of the optical axis of the first lens.

7. The method of manufacturing a multifocal lens according to claim 3, wherein the three kinds of lens materials are diluted so that the first lens and the third lens have the almost same diameter and the second lens has a diameter smaller than the diameter of the first lens and,wherein the optical axis of the third lens is adjusted to be the same of the optical axis of the first lens.

8. The method of manufacturing a multifocal lens according claim 3, wherein the first lens, the second lens, and the third lens are adjusted to have the identical optical axis.

9. The method of manufacturing a multifocal lens according to claim 3, wherein, in the step d), the first lens and the third lens are shaped to have the almost same diameter, the second lens is shaped as a doughnut-like, the second lens is adjusted to have an outer diameter smaller than the diameters of the first lens and the third lens; and the first lens, the second lens, and the third lens are shaped to have an identical optical axis.

10. The method of manufacturing a multi focal lens according to claims 3, wherein a glass transition temperature of the first lens material is Tg1, a glass transition temperature of the second lens material is Tg2, and a glass transition temperature of the third lens is Tg3;the respective glass transition temperatures have a relation of Tg1>Tg2>Tg3; andthe respective glass transition temperatures have a relation of Tg1>At2 and a relation of Tg2>At3.

11. The method of manufacturing a multifocal lens according to claim 2, wherein, in step a), the first lens material having the glass deformation point temperature At1 is diluted to provide a concave section of a upper surface at which the first lens is contacted with the second lens and an uneven section for a positioning at a concentric circle of the concave section;wherein in step b), the second lens material having the glass deformation point temperature At2 is placed on the concave section surrounded by the uneven section.

12. The method of manufacturing a multifocal lens according to claim 2, further comprising; forming a cutoff reference surface so that an outer periphery of the multifocal lens is positioned at the portion in which the lens is placed.

13. A multifocal lens manufactured by the method of manufacturing a multifocal lens according to claim 2.

14. The multifocal lens according to claim 1, wherein at least one kind of lens material among the M-kinds of lens materials is synthetic resin and at least one another type of lens material is glass.