Shaping an ophthalmic lens
Apparatus and methods are described including an additional lens ( 24 ) made from an amorphous viscoelastic material and having an optical design. A curvature of the additional lens ( 24 ) is changed such as to conform with a curvature of abase eyeglasses lens ( 22 ), without causing a loss of the optical design of the additional lens ( 24 ), by heating the additional lens ( 24 ) to a temperature at which a Tan Delta of the amorphous viscoelastic material is between 0.2 and 0.8, and shaping the additional lens ( 24 ). Subsequently, the additional lens ( 24 ) is adhered to the base eyeglasses lens ( 22 ). The optical design of the additional lens ( 24 ) is such that, upon being adhered to the base eyeglasses lens ( 22 ), the adhered base eyeglasses lens ( 22 ) and the additional lens ( 24 ) provide a combined lens ( 20 ) having a desired optical prescription. Other applications are also described.
1 . A method for use with a base eyeglasses lens, the method comprising:
forming an additional lens from an amorphous thermoplastic polymer, such that the additional lens has an optical design;
changing a curvature of the additional lens such that the curvature of the additional lens conforms with a curvature of the base eyeglasses lens, without causing a loss of the optical design of the additional lens, by:
heating the additional lens to a temperature at which a Tan Delta of the amorphous thermoplastic polymer is between 0.2 and 0.8, where the Tan Delta of the amorphous thermoplastic polymer is measured according to ASTM D 5023; and
while the additional lens is at said temperature at which the Tan Delta of the amorphous thermoplastic polymer is between 0.2 and 0.8, shaping the additional lens, such that the curvature of the additional lens conforms with the curvature of the base eyeglasses lens; and
subsequently, adhering the additional lens to the base eyeglasses lens, the optical design of the additional lens being such that, upon being adhered to the base eyeglasses lens, the adhered base eyeglasses lens and the additional lens provide a combined lens having a desired optical prescription.
2 . The method according to claim 1 , wherein heating the additional lens comprises heating the additional lens to a temperature at which a Tan Delta of the amorphous thermoplastic polymer is between 0.2 and 0.8 and to temperature that is lower than a temperature at which Tan Delta of the amorphous thermoplastic polymer is at its peak.
3 . The method according to claim 1 , wherein heating the additional lens comprises heating the additional lens to a temperature at which a Tan Delta of the amorphous thermoplastic polymer is between 0.2 and 0.8 and to a temperature that is at least 5 degrees Celsius below a temperature at which Tan Delta of the amorphous thermoplastic polymer is at its peak.
4 . The method according to claim 1 , wherein heating the additional lens to a temperature at which the Tan Delta of the amorphous thermoplastic polymer is between 0.2 and 0.8 comprises facilitating shaping the additional lens without the additional lens retaining significant internal stresses.
5 . The method according to claim 1 , wherein the base eyeglasses lens includes a single-focus optically-corrective lens, and wherein adhering the additional lens to the base eyeglasses lens comprises forming a combined progressive lens that provides a desired optical prescription.
6 . The method according to claim 1 , wherein shaping the additional lens comprises shaping the additional lens, while the additional lens is at said temperature at which the Tan Delta of the amorphous thermoplastic polymer is between 0.2 and 0.8, over a time period of between 0.1 seconds and 1 hour.
7 . The method according to claim 1 , wherein forming the additional lens from the amorphous thermoplastic polymer such that the additional lens has an optical design comprises forming the additional lens from the amorphous thermoplastic polymer using a forming process selected from the group consisting of: injection molding, injection-compression molding, compression molding, stamping, 3D-printing, casting, and any combination thereof.
8 . The method according to claim 1 , wherein heating the additional lens to a temperature at which the Tan Delta of the amorphous thermoplastic polymer is between 0.2 and 0.8 comprises heating the additional lens to a temperature at which the Tan Delta of the amorphous thermoplastic polymer is between 0.3 and 0.8.
9 . The method according to claim 8 , wherein heating the additional lens to a temperature at which the Tan Delta of the amorphous thermoplastic polymer is between 0.3 and 0.8 comprises heating the additional lens to a temperature at which the Tan Delta of the amorphous thermoplastic polymer is between 0.5 and 0.8.
10 . The method according to claim 1 , wherein heating the additional lens to a temperature at which the Tan Delta of the amorphous thermoplastic polymer is between 0.2 and 0.8 comprises heating the additional lens to a temperature at which the Tan Delta of the amorphous thermoplastic polymer is between 0.2 and 0.5.
11 . The method according to claim 10 , wherein heating the additional lens to a temperature at which the Tan Delta of the amorphous thermoplastic polymer is between 0.2 and 0.5 comprises heating the additional lens to a temperature at which the Tan Delta of the amorphous thermoplastic polymer is between 0.2 and 0.3.
12 . The method according to claim 1 , wherein the additional lens is coated with a functional coating, and wherein changing the curvature of the additional lens such that the curvature of the additional lens conforms with the curvature of the base eyeglasses lens comprises changing a curvature of the functional coating without causing a loss of function of the functional coating.
13 . The method according to claim 12 , wherein changing the curvature of the functional coating without causing a loss of function of the functional coating comprises changing a curvature of the functional coating without introducing significant stresses into the additional lens.
14 . The method according to claim 12 , wherein changing the curvature of the functional coating without causing a loss of function of the functional coating comprises changing a curvature of the functional coating without introducing significant stresses into the functional coating.
15 . The method according to claim 12 , wherein heating the additional lens to a temperature at which the Tan Delta of the amorphous thermoplastic polymer is between 0.2 and 0.8 comprises heating the additional lens to a temperature at which a Tan Delta of a material from which the functional coating is made is between 0.2 and 0.8.
16 . The method according to claim 12 , wherein the additional lens is coated with a hard coating, and wherein changing the curvature of the functional coating without causing a loss of function of the functional coating comprises changing a curvature of the hard coating without introducing significant stresses into the hard coating.
17 . The method according to claim 12 , wherein the additional lens is coated with a hard coating, and wherein changing the curvature of the functional coating without causing a loss of function of the functional coating comprises changing a curvature of the hard coating without introducing significant stresses into the additional lens.
18 . The method according to claim 12 , wherein the additional lens is coated with a hard coating, and wherein changing the curvature of the functional coating without causing a loss of function of the functional coating comprises changing a curvature of the hard coating without cracking the hard coating.
19 . The method according to claim 12 , wherein the additional lens is coated with a functional coating selected from the group consisting of: a hard coating, an anti-reflective coating, a super-hydrophobic coating, an antistatic coating, a clean coating, a blue-light filter, a reflective coating, an anti-UV coating, a photochromic coating, a polarizing coating, and any combination thereof.
20 . The method according to claim 1 , wherein shaping the additional lens comprises, while the additional lens is at said temperature at which the Tan Delta of the amorphous thermoplastic polymer is between 0.2 and 0.8, applying pressure of 0.01-100 kg per square cm to the additional lens.
21 . The method according to claim 20 , wherein shaping the additional lens comprises, while the additional lens is at said temperature at which the Tan Delta of the amorphous thermoplastic polymer is between 0.2 and 0.8, applying pressure of 0.2-1 kg per square cm to the additional lens.
22 . The method according to claim 1 , wherein shaping the additional lens such that the curvature of the additional lens conforms with the curvature of the base eyeglasses lens comprises changing a curvature of the additional lens by more than plus/minus 2 diopters.
23 . The method according to claim 22 , wherein shaping the additional lens such that the curvature of the additional lens conforms with the curvature of the base eyeglasses lens comprises changing a curvature of the additional lens by up to plus/minus 4 diopters.
24 . The method according to claim 1 , further comprising, subsequent to adhering the additional lens to the base eyeglasses lens, applying a heat treatment to the additional lens in order to release stresses from the additional lens.
25 . The method according to claim 24 , further comprising, subsequent to adhering the additional lens to the base eyeglasses lens, applying a pressure treatment to the combined lens such as to remove any vacant volumes which may be located between the additional lens and the base lens.
26 . The method according to claim 24 , further comprising, subsequent to adhering the additional lens to the base eyeglasses lens, applying a pressure treatment to the combined lens such as to remove any air bubbles which may be disposed between the additional lens and the base lens.
27 . The method according to claim 1 , wherein shaping the additional lens comprises, while the additional lens is at said temperature at which the Tan Delta of the amorphous thermoplastic polymer is between 0.2 and 0.8, pressing the additional lens into a form using a pressure-applying surface that is made of a relatively soft material.
28 . The method according to claim 27 , wherein shaping the additional lens while the additional lens is at said temperature at which the Tan Delta of the amorphous thermoplastic polymer is between 0.2 and 0.8 comprises directly heating the additional lens via the pressure-applying surface.
29 . The method according to claim 28 , wherein the pressure-applying surface comprises a cushion, and wherein directly heating the additional lens via the pressure-applying surface comprises directly heating the additional lens using a heated fluid that is disposed within the cushion.
30 . The method according to claim 28 , wherein directly heating the additional lens via the pressure-applying surface comprises directly heating the additional lens via a spiral heating element that is coupled to the pressure-applying surface.
31 . The method according to claim 30 , wherein gaps between adjacent windings of the spiral heating element decrease from a center of the spiral toward an outside of the spiral.
32 . The method according to claim 27 , wherein the pressure-applying surface is made of a material having a hardness of less than 90 Shore A.
33 . The method according to claim 32 , wherein the pressure-applying surface is made of a material having a hardness of between 20 and 85 Shore A.