FDM 3D printing of optical lens with high clarity and mechanical strength

Patent metadata

Field	Value
Publication number	US-12226951-B2
Application number	US-202017623684-A
Country	US
Kind code	B2
Filing date	Jul 1, 2020
Priority date	Jul 2, 2019
Publication date	Feb 18, 2025
Grant date	Feb 18, 2025

Abstract

The disclosure includes core-shell filament composition for additive manufacturing of ophthalmic lenses and ophthalmic lens components. The disclosure also includes a set of criteria for selecting core and shell thermoplastic combinations that exhibit high optical clarity, improved filament inter-strand diffusion, high inter-strand adhesion, and improved manufactured part strength when used in an additive manufacturing method like fused deposition modelling.

First claim

The invention claimed is:

1. An additive manufacturing method for fabricating an ophthalmic lens comprising:
feeding a first thermoplastic material having a first refractive index to a co-extrusion die;
feeding a second thermoplastic material having a second refractive index to a co-extrusion die;
co-extruding the first and second thermoplastic materials to produce a core-shell filament; and
building up multiple voxels of co-extruded core-shell filament to fabricate the ophthalmic lens;

wherein a difference between the first refractive index and the second refractive index is equal to or less than 0.1.

2. The method of claim 1 , wherein the co-extruded core-shell filament comprises an elongated core formed of the first thermoplastic material and a shell around the elongated core formed of the second thermoplastic material.

3. The method of claim 1 , wherein the first thermoplastic material has a glass transition temperature that is within 100° C. of the second thermoplastic material glass transition temperature.

4. The method of claim 1 , wherein the first thermoplastic material has a flexural modulus that is within 3,000 MPa of the second thermoplastic material flexural modulus.

5. The method of claim 1 , wherein at least one of the first thermoplastic material and the second thermoplastic material further comprises at least one of a flow improver, a near infra-red absorber, a plasticizer, and a compatibilizer.

6. The method of claim 1 , wherein adhesion between deposited filament voxels is at least 100 g/25 mm.

7. The method of claim 1 , wherein at least one of the first thermoplastic material and second thermoplastic material further comprises at least one or more of a flow improver, a plasticizer, and a compatibilizer.

Assignees

• Essilor Int

Inventors

• Shan Haifeng
• Chiu Hao-Wen
• Jallouli Aref

Classifications

• B29L2011/0016

  Lenses · CPC title

• B29K2995/0097

  Thickness · CPC title

• B29K2995/0082

  Flexural strength; Flexion stiffness · CPC title

• B29K2101/12

  Thermoplastic materials · CPC title

• B29C64/314

  Preparation · CPC title