Method for printing a thermoplastic film on an optical mold

Abstract

The present disclosure relates to a method of printing a thermoplastic film on an optical mold, the method comprising: adjusting a temperature of the optical mold to a first temperature; once the temperature of the optical mold reaches the first temperature, printing a first layer of the thermoplastic film on the optical mold; applying a vacuum to the optical mold to hold the thermoplastic film on the optical mold; adjusting the temperature of the optical mold to a second temperature; once the temperature of the optical mold reaches the second temperature, printing a second layer of the thermoplastic film on the first layer of the thermoplastic film; adjusting the temperature of the optical mold to a third temperature; once the temperature of the optical mold reaches the third temperature, annealing the first layer and the second layer; and removing the vacuum from the optical mold, thereby allowing the thermoplastic film comprising the annealed first layer and the annealed second layer to be removed from the optical mold.

Description

Background Technology

[0001] This disclosure relates to a method for printing thermoplastic films on optical molds.

[0002] Description of related technologies

[0003] Ophthalmic lens products often consist of a lens and a film, with the film typically laminated onto the optical surface of the lens. The film can be a thin, flat wafer. Thin, flat wafers containing thermoplastic films can be printed using additive manufacturing 3D printers for ophthalmic lens applications. However, printing thin, flat wafers can present several challenges due to the limited forces and heat during the printing process, such as voids between the thermoplastic filament strands and the layer, poor adhesion between the thermoplastic filament strands and the layer, film warping, and rough surfaces.

[0004] The preceding "Background Art" description is intended to provide an overall context for this disclosure. The inventors' work within the scope described in this background section, and aspects of the description that may not be otherwise considered prior art at the time of filing, are neither expressly nor implicitly acknowledged as prior art to this disclosure.

[0005] The present invention can address some of the disadvantages described above in the art, particularly by using the solutions set forth in the claims. Summary of the Invention

[0006] This disclosure relates to a method for printing thermoplastic films on optical molds.

[0007] This disclosure further relates to a method for printing a thermoplastic film on an optical mold, the method comprising: adjusting the temperature of the optical mold to a first temperature via a temperature control circuit system; printing a first layer of thermoplastic film on the optical mold once the temperature of the optical mold reaches the first temperature; applying a vacuum to the optical mold to hold the thermoplastic film on the optical mold; adjusting the temperature of the optical mold to a second temperature via the temperature control circuit system; printing a second layer of thermoplastic film on the first layer of the thermoplastic film once the temperature of the optical mold reaches the second temperature; adjusting the temperature of the optical mold to a third temperature via the temperature control circuit system; annealing the first and second layers once the temperature of the optical mold reaches the third temperature; and removing the vacuum from the optical mold, thereby allowing the removal of the thermoplastic film including the annealed first layer and the annealed second layer from the optical mold, wherein the first temperature may be between 10°C below and 30°C above the glass transition temperature of the thermoplastic film, the first layer of the thermoplastic film may be a thermoplastic surface layer comprising multiple thermoplastic layers, and the first layer of the thermoplastic film... The thickness can be between 10 micrometers and 500 micrometers; the second temperature can be equal to or higher than the glass transition temperature; the third temperature can be between the glass transition temperature and 60°C below the glass transition temperature; the temperature control circuit system can control one or more electric heating elements and / or microfluidic channels with circulating temperature-adjusting fluid to adjust the temperature of the optical mold; printing the first layer or printing the second layer includes printing using a single thermoplastic or at least two different thermoplastics to form a 2D or 3D structure and / or function; at least one of the at least two different thermoplastics can have a higher mechanical strength than another of the at least two different thermoplastics, and / or at least one of the at least two different thermoplastics can have a higher glass transition temperature than another of the at least two different thermoplastics; the at least two different thermoplastics form a homogeneous or heterogeneous structure and / or function; the at least two different thermoplastics can form a heterogeneous structure and / or function; wherein, the ΔE between the different thermoplastics can be less than 1; wherein... As defined by the CIE 76 formula, at least two different thermoplastics are modifiable by light filters, dyes, additives, or fillers, wherein the light filters may include one of the group consisting of UV absorbers, blue cut-off filters, and NIR cut-off filters; wherein the dyes may include one of the group consisting of color balancing dyes, color enhancing dyes, photochromic dyes, and dichroic dyes; wherein the additives may include one of the group consisting of plasticizers, heat stabilizers, light stabilizers, flow improvers, and release agents; and wherein the fillers may include one of the group consisting of particles, fibers, and nanotubes.

[0008] This disclosure further relates to a thermoplastic film for an ophthalmic lens formed on an optical mold, the thermoplastic film comprising: a first layer of thermoplastic film formed on the optical mold, wherein the temperature of the optical mold can be adjusted to a first temperature during the formation of the first layer of thermoplastic film; and a second layer of thermoplastic film formed on the first layer, wherein the temperature of the optical mold can be adjusted to a second temperature during the formation of the second layer of thermoplastic film. The thermoplastic film of the ophthalmic lens may further include one or more optical surface features, including spherical, aspherical, bifocal, trifocal, progressive, microlens, Fresnel structure, and moth-eye structure.

[0009] This disclosure further relates to an optical mold structure for forming a thermoplastic film, the optical mold structure comprising: a temperature control circuit system that controls one or more electrically heating elements and / or microfluidic channels; an optical mold on the temperature control circuit system for forming a first layer and a second layer of the thermoplastic film, wherein the optical mold further comprises one or more optical surface features, including spherical, non-spherical, bifocal, trifocal, progressive, microlens, Fresnel structure and moth-eye structure; and a vacuum device attached to the optical mold for holding the thermoplastic film on the optical mold.

[0010] This disclosure further relates to an optical mold structure for forming a thermoplastic film, the optical mold structure comprising: a temperature control circuit system that controls one or more electrothermal elements and / or microfluidic channels; an optical mold on the temperature control circuit system for forming a first layer and a second layer of the thermoplastic film; and a vacuum device attached to the optical mold for holding the thermoplastic film on the optical mold.

[0011] The preceding paragraphs are provided as a general introduction and are not intended to limit the scope of the appended claims. The described features and further advantages will be best understood by referring to the following detailed description taken in conjunction with the accompanying drawings. Attached Figure Description

[0012] A more comprehensive understanding of this disclosure and its many incidental advantages will be readily obtained when considered in conjunction with the accompanying drawings, as this will be better understood by referring to the following detailed description, in which the drawings are shown:

[0013] Figure 1 An illustration of a 3D fused deposition modeling (FDM) printer within the scope of this disclosure:

[0014] Figure 2A This is a top view of a thin, flat wafer printed by a 3D fused deposition modeling printer, within the scope of this disclosure;

[0015] Figure 2B A side view of a thin, flat wafer printed by a 3D fused deposition modeling printer, within the scope of this disclosure:

[0016] Figure 3A , Figure 3B and Figure 3C This is a side view of different thin curved wafers used in ophthalmic lenses within the scope of this disclosure;

[0017] Figure 4 This is an illustration of a side view of an optical mold having a temperature control circuitry system for 3D FDM printing, within the scope of this disclosure.

[0018] Figure 5 A method for printing a thermoplastic layer or thermoplastic product formed on an optical mold, within the scope of this disclosure:

[0019] Figure 6 This is an illustration of an optical mold heated by a temperature control circuit system, within the scope of this disclosure.

[0020] Figure 7A and Figure 7B This is an illustration of multiple thermoplastic layers printed on an optical mold, within the scope of this disclosure;

[0021] Figure 8A , Figure 8B and Figure 8C This is an illustration of a heterogeneous structure formed by the combination of a first thermoplastic material and a second thermoplastic material in a printed layer, within the scope of this disclosure.

[0022] Figure 9 Printed copolyester / polycarbonate (PC) thin spherical wafers within the scope of this disclosure; and

[0023] Figure 10 These are printed TPU and PC thin spherical wafers within the scope of this disclosure. Detailed Implementation

[0024] As used herein, the term "a" or "an" is defined as one or more. The term "multiple" is defined as two or more. The term "another" is defined as at least a second or more. The terms "including" and / or "having" are defined as comprising (i.e., open-ended language). Throughout this document, references to "an embodiment," "some embodiments," "embodiment," "implementation," "example," or similar terms mean that a specific feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of this disclosure. Therefore, the appearance of such phrases throughout this specification or in various places does not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics can be combined in any suitable manner without limitation in one or more embodiments.

[0025] Unless otherwise specified, the features and embodiments described herein can be operated in any arrangement together.

[0026] The terms “about” and “approximately” are defined as close to what a person skilled in the art would understand.

[0027] The methods disclosed herein may “include” all the specific ingredients, components, compositions, etc. disclosed herein, or “consistently comprise” or “composed of” all the specific ingredients, components, compositions, etc. disclosed herein.

[0028] This disclosure describes a method for printing thermoplastic films (e.g., thin and curved wafers) on optical molds for ophthalmic lens applications. This method can improve optical clarity, mechanical strength, and optical accuracy while avoiding warping and rough surfaces.

[0029] This disclosure discloses a method for forming a thermoplastic film (e.g., a thin and curved wafer) on an ophthalmic lens on an optical mold. For example, the thermoplastic film can be formed as a thin and curved wafer on an ophthalmic lens. Accordingly, this method can provide a thermoplastic film of better quality for ophthalmic lenses.

[0030] Now turn to the attached image. Figure 1 An exemplary three-dimensional fused deposition modeling (FDM) process useful within the scope of this disclosure is shown.

[0031] One or more thermoplastic filaments 104 can be drawn from spool 102. The thermoplastic filaments 104 can pass through extruder 106 and then through heating block 108 to heated nozzle 110. The molten thermoplastic filaments 104 can then be extruded onto print bed 112 in the XY axis direction, where the hot wire strands can be laid side by side. Once the first layer can be completed, print bed 112 can be lowered in the Z axis direction (or nozzle raised in the Z axis direction), and then a second layer can be deposited. The above steps can be repeated until the entire structure or the entire layer stack can be completed, forming a printed wafer 114. While these hot wire strands are still molten, they can be fused together and then cooled to form a solid structure or layer stack.

[0032] Referring to Table 1, within the scope of this disclosure, some exemplary commercial 3D fused deposition modeling printers and their heating capabilities are listed.

[0033] Depending on the printer design, Figure 1 Some print beds 112 can be heated, but only to a limited temperature. For example, as shown in Table 1, with the Ultimaker S5, print bed 112 can be heated only up to 140°C. Alternatively, printing can be performed inside a closed chamber that can be heated to a certain temperature. For example, as shown in the table, with the PartPro300 xT, print bed 112 can be heated up to 70°C. Some printers may have a heated chamber that can be heated to 80°C, such as the Roboze One+400. After printing is complete, the part (e.g., a printed layer or structure) can typically be cooled under ambient conditions to form a solid part.

[0034] Table 1. List of FDM 3D printers with heating capabilities.

[0035]

[0036] refer to Figure 2A and Figure 2B Within the scope of this disclosure, Figure 2A An exemplary top view of a thin, flat wafer printed by the 3D fused deposition modeling printer described above is shown. Within the scope of this disclosure, it is possible to... Figure 2B An exemplary side view of a thin, flat wafer is shown.

[0037] Several problems exist with 3D FDM printing, including gaps between the filament strands and the layers of thermoplastic filament 104, poor adhesion between the filament strands and between the layers of thermoplastic filament 104, warping of the printed wafer 114, and a rough surface of the printed wafer 114. These problems are likely primarily due to the limited forces and heat that can be applied in 3D FDM printing compared to conventional manufacturing processes (e.g., injection molding, compression molding, etc.). The forces in 3D FDM printing can be much smaller than in conventional manufacturing processes, and the heat can be more difficult to control. Therefore, films or layers printed by 3D FDM printing often exhibit the following disadvantages: poor optical properties, poor mechanical strength, and poor dimensional accuracy. In particular, poor mechanical strength may be caused by poor adhesion between the filament strands and between the layers.

[0038] refer to Figure 3A , Figure 3B and Figure 3C It can list side views of different thin curved wafers used in ophthalmic lenses.

[0039] refer to Figure 3A Within the scope of this disclosure, an exemplary cross-section of a thin spherical wafer on an ophthalmic lens may be shown. The thin spherical wafer comprises components described above. Figure 1 The system 100 shown prints three layers of thermoplastic films 302, 304, and 306. Thin spherical wafers can be integrated into ophthalmic lenses. However, several problems need to be addressed, such as high surface roughness, high haze values, low dimensional accuracy, low surface curvature accuracy, and low surface replication rate. To achieve low optical offset, Figure 3A The thin wafers in the process should be printed as precisely as possible so that a spherical surface can be achieved.

[0040] refer to Figure 3B Within the scope of this disclosure, an exemplary cross-section of a thin, curved wafer with an optical design on its top surface may be shown. The thin, curved wafer comprises, as described above... Figure 1 The system 100 shown in the figure prints three layers of thermoplastic films 308, 310, and 312. Optical power can be calculated using an optical design for a thin, curved wafer, and the surface curvature should match the optical design. The surface can include a spherical surface, a non-spherical surface, a cylindrical surface, or a progressively curved surface.

[0041] refer to Figure 3C This illustrates a cross-section of a thin, curved wafer with a microstructured front surface. Thin, curved wafers can include those described above. Figure 1 The system 100 shown prints four layers of thermoplastic films 314, 316, 318, and 320. For films with similar properties... Figure 3CThe front surface of the microstructure in a curved wafer is important, and therefore a method for forming a microstructured front surface on a thin curved wafer may be needed.

[0042] refer to Figure 4 Within the scope of this disclosure, an exemplary side view of an optical mold having a temperature control circuitry system for 3D FDM printing may be shown.

[0043] The optical mold structure 400 may include a vacuum device 402, an optical mold 404, and a temperature control circuit system 406. The temperature control circuit system 406 may include a temperature control housing 408 and a microfluidic channel 410, such as... Figure 4 As shown. The surface of the optical mold 404 may have a small opening. The opening can be connected to a vacuum suction member 402, which can be applied during the printing process to press any film (e.g., a thermoplastic film) and apply force to it. The optical mold 404 may have a highly polished surface suitable for the thermoplastic film to be printed, to produce a high-quality thermoplastic film for optical design. The temperature control circuitry 406 can use the microfluidic channel 410 to regulate the temperature of the temperature control housing 408 and further control the temperature of the optical mold 404 for heating or cooling.

[0044] The surface of the optical mold 404 can be a smooth surface. The smooth surface can be, but is not limited to, a curved spherical or aspherical surface. The smooth surface can also have, but is not limited to, optical designs for progressive lenses, bifocal lenses, or trifocal lenses. The optical mold 404 can have a radius between 10 mm and 1000 mm.

[0045] The surface of the optical mold 404 can be a surface with microstructures. These microstructures can be, but are not limited to, microlenses, Fresnel lenses, or moth-eye structures. Microlens microstructures can be used for myopia control. Fresnel lens microstructures can be used to adjust the optical power of ophthalmic lenses. Moth-eye microstructures can provide one or more features such as anti-reflection and anti-fogging.

[0046] The temperature control circuit system 406 may include a temperature control housing 408 and a microfluidic channel 410. The temperature control circuit system 406 can be used to control the temperature of the optical mold 404. For example, during the printing process, the temperature control circuit system 406 can control the temperature of the optical mold 404 to heat the optical mold above the glass transition temperature of the thermoplastic material used for printing, so as to keep the printed thermoplastic material in a softened state. Keeping the thermoplastic material in a softened state can be beneficial because it can improve the reproduction quality of the mold surface curvature and microstructure, and can also improve the interlayer diffusion and adhesion of the thermoplastic layer. In another arrangement, after the printing process, the temperature control circuit system 406 can control the temperature of the optical mold 404 to cool slowly until the temperature reaches 20°C to 40°C below the glass transition temperature of the thermoplastic material, or until the printed thermoplastic layer solidifies or hardens sufficiently to allow the thermoplastic layer to be removed while maintaining its shape without warping.

[0047] The opening inlet can be connected to the vacuum suction member 402. The opening inlet with the vacuum suction member 402 can be used to apply a vacuum or airflow. For example, a vacuum can be applied after the printing of the first thermoplastic film is completed in the printing process. The vacuum can be used to hold the first thermoplastic film (e.g., a wafer) to deform the wafer to match the curvature and / or microstructure of the mold surface. In another arrangement, cold air, for example, at 10°C to 30°C, can be applied after the printing process. The cold air can be used to reduce the adhesion between the wafer and the optical mold 404, and then the wafer can be easily and quickly removed.

[0048] refer to Figure 5 Within the scope of this disclosure, an exemplary method for printing a thermoplastic layer or thermoplastic product formed on an optical mold is shown. Method 500 can be implemented by the following steps: First, at step S502, heating as previously... Figure 4 The optical mold 404 shown is available at temperatures between 10°C below and 30°C above the glass transition temperature of the thermoplastic material, for example, between 5°C below and 20°C above the glass transition temperature of the thermoplastic material, between 5°C below and 10°C above the glass transition temperature of the thermoplastic material, between 5°C below and 1°C above the glass transition temperature of the thermoplastic material, between 5°C below and 1°C above the glass transition temperature of the thermoplastic material, or between 1°C below and 1°C above the glass transition temperature of the thermoplastic material.

[0049] At S504, a first layer of thermoplastic film can be printed. The first layer can be a surface layer, and the surface layer can include one or more thermoplastic layers. The first layer can be made by melting a thermoplastic filament and extruding the molten filament onto an optical mold 404, wherein the molten filament can be laid as hot-wire strands onto the optical mold 404. The hot-wire strands can then be laid side-by-side on the optical mold 404.

[0050] At S506, a vacuum can be applied immediately after printing the first layer. The vacuum can be used to hold the optical mold 404 in place and to deform the first layer to conform to the curvature or microstructure of the surface of the optical mold 404.

[0051] At steps S508 to S510, the temperature of the optical mold 404 can be reduced to a temperature equal to or higher than the glass transition temperature of the thermoplastic material. Then, one or more layers can be printed on the first layer. Therefore, one or more layers can be printed with good adhesion between strands and between layers, and with good mechanical integrity to maintain dimensional accuracy and stability.

[0052] At S512, the temperature of the optical mold can be reduced to a temperature between the glass transition temperature and 60°C below the glass transition temperature, for example, a temperature between the glass transition temperature and 50°C below the glass transition temperature, a temperature between the glass transition temperature and 40°C below the glass transition temperature, a temperature between the glass transition temperature and 30°C below the glass transition temperature, a temperature between the glass transition temperature and 20°C below the glass transition temperature, or a temperature between the glass transition temperature and 10°C below the glass transition temperature.

[0053] At S514, the optical mold 404 can be maintained at the temperature of step S512 for annealing. Annealing at this temperature can remove stress generated during the printing process.

[0054] At steps S516 to S518, after the first layer and one or more layers have become hard and solid, the vacuum can be released. Cold air (e.g., 10°C to 30°C, 10°C to 20°C, 15°C to 30°C, or 15°C to 20°C) can be applied to help cool the optical mold 404 and the first layer and one or more layers. Then, after the first layer and one or more layers have become solid and hard, the first layer and one or more layers can be removed from the optical mold 404.

[0055] refer to Figure 6Within the scope of this disclosure, an exemplary optical mold 404 heated by a temperature control circuit system 406 can be shown. The nozzle 602 can be heated, and the thermoplastic filament 604 can be heated into a hot thermoplastic filament 606. The hot thermoplastic filament 606 can then be extruded from the nozzle 602. As previously described... Figure 4 As described herein, the optical mold 404 can be heated or cooled by a temperature control circuit system 406. The temperature control circuit system 406 may have a temperature control housing 408 and a microfluidic channel 410.

[0056] Thermoplastic filaments or three-dimensional thermoplastic filaments can be produced by extrusion from nozzle 602. The process can begin by feeding thermoplastic granules through a feeder into an extruder or a hopper on nozzle 602. The thermoplastic granules can then be melted and extruded into monofilaments through a single-hole die. A melt pump can be added between the die and the individual extruder for high-precision flow rate control. The monofilaments can then be drawn through a water or air bath. Furthermore, the diameter of the thermoplastic filaments can be adjusted by the ratio of melt flow rate to filament winding speed.

[0057] 3D printers can be, but are not limited to, MakerGear M2, Ultimaker S5, PartPro300 Xt, RizeOne, Orboze one, Lulzbot TAZ 6, Stratasys F 170, F270, F370, etc.

[0058] During the 3D FDM printing process of thermoplastic layers or films, the optical mold 404 can be heated to a temperature between 10°C below and 30°C above the glass transition temperature of the thermoplastic material. A microfluidic channel 410 can be injected with a hot fluid at a temperature between 10°C below and 30°C above the glass transition temperature of the thermoplastic material, thereby heating the temperature control circuitry 406. The optical mold 404 is then heated to the desired temperature. A heated filament 606 can then be laid on the optical mold to form a layer of product 608 or thermoplastic film, while the optical mold 404 has a temperature between 10°C below and 30°C above the glass transition temperature of the thermoplastic material. As previously stated... Figure 6 As described, maintaining the optical mold at this temperature is beneficial for improving the adhesion between the thermoplastic strands on the optical mold 404 and improving mechanical integrity to maintain dimensional accuracy and stability, as well as for replicating the mold surface with high definition.

[0059] refer to Figure 7A and Figure 7BWithin the scope of this disclosure, exemplary multiple thermoplastic layers printed on an optical mold may be shown. Multiple thermoplastic layers may be printed on the same layer or different layers. Multiple thermoplastic layers may be used to form two-dimensional or three-dimensional structures, such as... Figure 7A and Figure 7B As shown, different structures can be used to improve optical functionality or optical properties. For example, in Figure 7A The image shows a printed wafer with a homogeneous thermoplastic structure. A top view of the printed wafer is shown in image 702. A side view of the printed wafer is shown in image 704. Printed wafer 702 may include a top film having a first thermoplastic material 706. Printed wafer 704 may also include a bottom film having a second thermoplastic material 708.

[0060] The first thermoplastic material 706 can be used to print the functional layer of the final product. The layer printed from the first thermoplastic material 706 can serve one or more functions. These functions may include, but are not limited to, colorability, anti-fogging, antistatic, scratch-resistant, stain-resistant, anti-reflective, sun-protective, photochromic, or light-filtering properties. The second thermoplastic material 708 can be used to print the base layer of the final product. The layer printed from the second thermoplastic material 708 can have the following characteristics: high mechanical strength, high glass transition temperature, and good compatibility with the lens substrate. The combination of the first and second thermoplastic materials in the printed layer can form a structure such as... Figure 7A The homogeneous structure shown.

[0061] exist Figure 7B The image shows another printed wafer with a homogeneous thermoplastic structure. A top view of the printed wafer is shown in image 710. A side view of the printed wafer is shown in image 712. Printed wafer 712 may include a film having a first thermoplastic material 706 on its left side. Printed wafer 704 may also include a film having a second thermoplastic material 708 on its right side.

[0062] The combination of the first thermoplastic material and the second thermoplastic material in the printed layer can form a structure such as Figure 8A , Figure 8B and Figure 8C The heterogeneous structure is shown. Several conditions may need to be considered during the formation of the heterogeneous structure. The first condition is that the difference in refractive index (RI) between the first and second thermoplastic materials should be less than 0.01. A difference in RI less than 0.01 can prevent light scattering. The second condition is that the modulus (E) between the first and second thermoplastic materials should be less than 1. A modulus less than 1 between the first and second thermoplastic materials can prevent color heterogeneity. The difference in modulus (ΔE) between the two thermoplastic materials can be calculated using the following function:

[0063] As defined by the CIE 76 formula, the CIE 76 formula is a formula related to the color difference of a set of CIELAB coordinates.

[0064] exist Figure 8A The diagram illustrates a printed wafer with a heterogeneous thermoplastic structure. A top view of the printed wafer is shown in diagram 802. Side views of the printed wafer are shown in diagrams 804 and 806. Printed wafer 802 may include a structure of horizontal strips in which a first thermoplastic material 808 and a second thermoplastic material 810 can be connected to each other. The printed wafer may have a side view in which the first and second thermoplastic materials can completely fill from the top to the bottom of the wafer, as shown in diagram 804. The printed wafer may have another side view in which the first and second thermoplastic materials can periodically and vertically fill each other, as shown in diagram 806.

[0065] exist Figure 8B Within the scope of this disclosure, an exemplary second printed wafer having a heterogeneous thermoplastic structure may be shown. A top view of the printed wafer is shown in 812. Side views of the printed wafer are shown in 814 and 816. The printed wafer 812 may include a target-shaped structure in which a first thermoplastic material 808 and a second thermoplastic material 810 may be connected to each other. The printed wafer may have a side view in which the first thermoplastic material and the second thermoplastic material completely fill from the top of the wafer to the bottom of the wafer, as shown in 814. The printed wafer may have another side view in which the first thermoplastic material and the second thermoplastic material may periodically and vertically fill each other, as shown in 816.

[0066] In Figure 8°, within the scope of this disclosure, an exemplary third printed wafer with a heterogeneous thermoplastic structure can be shown. A top view of the printed wafer is shown in 818. A side view of the printed wafer is shown in 820. The printed wafer 818 may include a lattice structure in which a first thermoplastic material 808 and a second thermoplastic material 810 may be connected to each other. The printed wafer may have a side view in which the first thermoplastic material and the second thermoplastic material may periodically and vertically fill each other, as shown in 820.

[0067] The first and second thermoplastic materials can be modified using light filters, dyes, additives, or fillers. Light filters can include UV cutoff, blue cutoff, time-varying cutoff, and NIR cutoff filters. Dyes can include color-balancing dyes, color-enhancing dyes, photochromic dyes, and dichroic dyes. Additives can include plasticizers, heat stabilizers, light stabilizers, flow improvers, and release agents. Fillers can include particles, fibers, and nanotubes.

[0068] In addition to the functions of the thermoplastic material, the first and second thermoplastic materials can also be selected based on their properties and structure. Details of the selection are shown in Table 2.

[0069] Table 2. Properties, Functions, and Selection Criteria of Thermoplastics

[0070]

[0071]

[0072] Within the scope of this disclosure, the properties, functions, and selection criteria of the thermoplastic materials may be shown in Table 2. As mentioned in the preceding paragraph associated with Figure 7, the first thermoplastic material may be used as a functional layer, and the second thermoplastic material may be used as a base layer. The first thermoplastic material may have better adhesion than the second thermoplastic material.

[0073] As mentioned above and in Table 2, for heterogeneous structures on printed wafers, the difference in refractive index (RI) between the first thermoplastic material and the second thermoplastic material can be less than 0.01 to avoid light scattering. For heterogeneous structures on printed wafers, the color difference (ΔE) between the first thermoplastic material and the second thermoplastic material can also be less than 1 to avoid color heterogeneity.

[0074] One type of thermoplastic material can be selected due to its low glass transition temperature, low viscosity, and low modulus, resulting in better flowability. Because of this better flowability, the selected thermoplastic material can fill the gaps between the printed pattern and the filament.

[0075] Functional layers can have one or more functions, such as colorability, anti-fogging, anti-static, scratch resistance, stain resistance, anti-reflective properties, sun protection, photochromism, and light filtering. Base layers can have one or more functions, such as higher mechanical integrity, higher glass transition temperature, and better adhesion to the lens substrate. When the printed pattern is a homogeneous structure, the functional layer can be the optical surface of the product.

[0076] A list of thermoplastic materials can be found in Table 3. These thermoplastic materials may include polycarbonate (PC), polyamide (PA), thermoplastic polyurethane (TPU), poly(methyl methacrylate) (PMMA), polyester, and polysulfone (PSU). Additionally, thermoplastic materials may also be cyclic olefin copolymers (COC), cyclic olefin polymers (COP), etc. Thermoplastic materials can also be modified with light filters such as blue cut-off filters, time-varying cut-off filters, and NIR cut-off filters. Thermoplastic materials can also be modified with dyes such as color-balancing dyes, color-enhancing dyes, photochromic dyes, and dichroic dyes. Thermoplastic materials can also be modified with additives such as plasticizers, heat stabilizers, light stabilizers, flow modifiers, and release agents.

[0077] Table 3. List of some thermoplastic candidates

[0078]

[0079]

[0080] Using the selection criteria and thermoplastic materials described in Tables 2 and 3, thin and curved wafers can be produced. For ophthalmic lens applications, the printed thin and curved wafers can possess one of the following characteristics: high surface smoothness (e.g., roughness values ​​can be below 50 nm), high dimensional accuracy, high surface curvature accuracy, high surface microstructure replication, minimal voids within the printed structure, and various functions for ophthalmic lens applications. These functions can be those described above, such as colorability, anti-fogging, antistatic, scratch-resistant, stain-resistant, anti-reflective, sun-resistant, photochromic, and light-filtering. The substrate layer can possess one or more functions, such as higher mechanical integrity, higher glass transition temperature, and better adhesion to the lens substrate.

[0081] The following describes an example of the 3D FDM printing process.

[0082] Example 1 is a polycarbonate (PC) wafer with a progressive curvature on a convex surface.

[0083] Within the scope of this disclosure, the characteristics and details of the PC chip can be shown in Table 4. Within the scope of this disclosure, the details of the optical mold and 3D printing parameters can be shown in Table 5. Figure 4The optical mold 404 can first be heated to 175°C, which is 30°C higher than the glass transition temperature of the polycarbonate (PC). PC filaments are extruded and then printed onto the optical mold to form a surface layer on the optical mold 404. Once the surface layer is formed, a vacuum can be applied. The temperature of the optical mold 404 can then be lowered to 150°C (slightly higher than the glass transition temperature of the PC), and subsequent thermoplastic layers can be printed. Because the surface layer can be printed at a temperature higher than the glass transition temperature of the PC, and a vacuum can be applied, the optical design of the optical mold can be replicated with high precision. The surface layer can be a layer on the surface of a thin wafer. Subsequent thermoplastic layers can be printed onto the optical mold 404 at a lower temperature, but still higher than the glass transition temperature of the PC, to ensure that the previous layer is not too soft to be printed on. After the printing process, the temperature of the optical mold 404 can be lowered to 130°C, which is slightly lower than the glass transition temperature of the PC, to ensure that the molecular chains of the PC are fully relaxed and internal stress is removed to prevent warping of the thermoplastic film. Then, the temperature of the optical mold can be reduced to 60°C, so that the thermoplastic layer does not stick to the optical mold 404 and can be easily removed.

[0084] Table 4. PC characteristics and chip specifications.

[0085]

[0086] Table 5. FDM 3D printing process and results of PC wafers with progressive curvature on the Cx convex surface.

[0087]

[0088]

[0089] Example 2 is a polyamide (PA) thin wafer with Fresnel microstructures on a convex surface.

[0090] Within the scope of this disclosure, the characteristics and details of the PA wafer can be shown in Table 6. Within the scope of this disclosure, the details of the optical mold and 3D printing parameters can be shown in Table 7. The optical mold 404 can first be heated to 160°C, which can be 20°C higher than the glass transition temperature of the PA. The PA filament is extruded and printed to form a surface layer. The surface layer can be a layer on the surface of a thin wafer. Once the surface layer is formed, a vacuum can be applied. The temperature of the optical mold can then be lowered to 140°C (which can be the same as the glass transition temperature of the PA), and subsequent thermoplastic layers can be printed. Because the surface layer can be printed at a temperature higher than the glass transition temperature of the PA, and a vacuum can be applied, the Fresnel microstructure design of the optical mold can be replicated with high precision. The thermoplastic layers can be printed onto the optical mold at a lower temperature, but equal to the glass transition temperature of the PA, to ensure that the previous layers are not difficult to print on. After the printing process is complete, the temperature of the optical mold 404 can be maintained at 120°C, which is slightly lower than the glass transition temperature of the PA, to ensure that the molecular chains of the PA can be fully relaxed and internal stress can be removed to avoid any warping of the thermoplastic layer or film. The temperature of the optical mold 404 can eventually be reduced to 60°C, so that the thermoplastic layer or film does not stick to the mold and can be easily removed.

[0091] Table 6. PA characteristics and chip specifications.

[0092]

[0093]

[0094] Table 7. FDM 3D printing process and results of PA thin wafers with Fresnel microstructures on Cx surfaces.

[0095]

[0096] Example 3 is a copolyester / P℃ thin spherical wafer with colorability.

[0097] Copolyester and PC can be used as raw materials to print colorable thin spherical wafers. Copolyester can be selected as a functional layer on the front surface of the thin spherical wafer due to its colorability. PC can be selected as a base layer on the back surface of the thin spherical wafer due to its higher glass transition temperature and higher mechanical strength. Within the scope of this disclosure, the properties of the thermoplastic materials and the specifications of the optical molds can be shown in Table 8.

[0098] Table 8. Properties and wafer specifications of PC and copolyester.

[0099]

[0100] Within the scope of this disclosure, it is possible to Figure 9 The image shows a printed copolyester / PC thin spherical wafer. A top view of the printed wafer is shown in image 902. A side view of the printed wafer is shown in image 904. Printed wafer 902 may include a top or surface layer made of copolyester 906 and a bottom or base layer made of PC 908. The printed wafer may have the same curvature as an ophthalmic lens, allowing the printed wafer to be held on an ophthalmic lens.

[0101] Within the scope of this disclosure, the 3D FDM printing process and results for colorable copolyester / PC wafers can be shown in Table 9. For example, Table 9 lists the temperatures for nozzles and optical molds using copolyester as the surface layer and PC as the base layer. Furthermore, the temperatures used for annealing and removing parts (e.g., thermoplastic layers) are also shown in Table 9.

[0102] Table 9. FDM 3D printing process and results of colorable copolyester / P℃ thin wafers.

[0103]

[0104]

[0105] Example 4 is a thermoplastic polyurethane (TPU) / PC wafer with high definition and high strength. TPU / PC wafers can have other functions such as photochromism and light filtering.

[0106] TPU and PC can be used as raw materials to print thin, flat wafers with high definition and high strength. TPU is chosen as the functional layer to fill the gaps between PC filaments due to its low glass transition temperature and good adhesion to PC. PC can be chosen as the substrate layer due to its high glass transition temperature and high mechanical strength. The refractive index difference between these two thermoplastic materials can be less than 0.01, thus eliminating light scattering between the two thermoplastic filaments. Within the scope of this disclosure, the properties and specifications of the optical molds can be shown in Table 10. Within the scope of this disclosure, it is possible to... Figure 10 The image shows a printed thin, flat wafer.

[0107] Table 10. Characteristics and chip specifications of TPU and PC.

[0108]

[0109]

[0110] Within the scope of this disclosure, it is possible to Figure 10The printed TPU / PC thin flat wafer is shown in section 1002. A top view of the printed wafer is shown in section 1003. A side view of the printed wafer is shown in section 1004. The printed wafer 1002 may include a top or surface layer made of TPU 1006 and a bottom or base layer made of PC 1008.

[0111] As listed in Table 11, the printed wafer can be a 1 mm thick flat wafer produced from TPU and PC. The wafer can have high transparency (e.g., Tv% (D65) > 80% at 1 mm, where Tv% (D65) can be the total visible light transmittance, which can be measured under a D65 light source as defined by the International Commission on Illumination (CIE)) and high mechanical strength (e.g., impact strength > 60 J / m (cantilever beam notch, 23°C, as defined by ASTM D256)). The wafer can have other functionalities such as photochromism and light filtering. Light filtering can be achieved by adding photochromic dyes to the TPU layer and light filters to the TPU and / or PC layers. For example, Table 11 can list each temperature for nozzles and optical molds using TPU as the surface layer and PC as the base layer. Furthermore, within the scope of this disclosure, the temperatures for annealing and removing parts (e.g., thermoplastic layers) can also be shown in Table 11. Table 11. FDM 3D printing process and results of TPU / PC thin wafers with high resolution and high strength.

[0112]

[0113]

[0114] Clearly, many modifications and variations are possible based on the above teachings. Therefore, it should be understood that the invention can be practiced in ways other than those specifically described herein, within the scope of the appended claims.

[0115] The embodiments disclosed herein may also be described as shown in parentheses below.

[0116] (1) A method for printing a thermoplastic film on an optical mold, the method comprising: adjusting the temperature of the optical mold to a first temperature via a temperature control circuit system; printing a first layer of thermoplastic film on the optical mold once the temperature of the optical mold reaches the first temperature; applying a vacuum to the optical mold to hold the thermoplastic film on the optical mold; adjusting the temperature of the optical mold to a second temperature via the temperature control circuit system; printing a second layer of thermoplastic film on the first layer of the thermoplastic film once the temperature of the optical mold reaches the second temperature; adjusting the temperature of the optical mold to a third temperature via the temperature control circuit system; annealing the first and second layers once the temperature of the optical mold reaches the third temperature; and removing the vacuum from the optical mold, thereby allowing the removal of the thermoplastic film comprising the annealed first layer and the annealed second layer from the optical mold.

[0117] (2) According to the method of (1), wherein the first temperature is between 10°C below the glass transition temperature of the thermoplastic film and 30°C above the glass transition temperature, for example, between 5°C below the glass transition temperature of the thermoplastic film and 20°C above the glass transition temperature, between 5°C below the glass transition temperature of the thermoplastic film and 10°C above the glass transition temperature, or between 1°C below the glass transition temperature of the thermoplastic film and 1°C above the glass transition temperature.

[0118] (3) According to the method of (1), wherein the first layer of the thermoplastic film is a thermoplastic surface layer comprising multiple thermoplastic layers, and wherein the thickness of the first layer of the thermoplastic film is between 10 micrometers and 500 micrometers, for example, 20 micrometers, 30 micrometers, 40 micrometers, 50 micrometers, 60 micrometers, 70 micrometers, 80 micrometers, 90 micrometers, 100 micrometers, 200 micrometers, 300 micrometers, 400 micrometers or 450 micrometers.

[0119] (4) According to the method of (1), the second temperature is equal to or higher than the glass transition temperature.

[0120] (5) According to the method of (1), wherein the third temperature is between the glass transition temperature and 60°C below the glass transition temperature.

[0121] (6) According to the method of (1), wherein the temperature control circuit system controls one or more electric heating elements and / or a microfluidic channel circulated with temperature-adjusting fluid to adjust the temperature of the optical mold.

[0122] (7) According to the method of (1), wherein printing the first layer or printing the second layer includes printing using a single thermoplastic or at least two different thermoplastics to form a 2D or 3D structure and / or function.

[0123] (8) The method according to any one of (1) and (7), wherein at least one of the at least two different thermoplastics has a higher mechanical strength than the other of the at least two different thermoplastics, and / or at least one of the at least two different thermoplastics has a higher glass transition temperature than the other of the at least two different thermoplastics.

[0124] (9) The method according to any one of (1) and (7), wherein at least two different thermoplastics form a homogeneous or heterogeneous structure and / or function.

[0125] (10) The method according to any one of (1), (7) and (9), wherein at least two different thermoplastics form a heterogeneous structure and / or function, wherein the difference in refractive index (RI) between the different thermoplastics is less than 0.01, 0.005 or 0.001, and / or wherein the ΔE between the different thermoplastics is less than 1, 0.5, 0.3, 0.2 or 0.1, wherein, As defined by the CIE76 formula.

[0126] (11) The method of any one of (1) and (7), wherein at least two different thermoplastics are modifiable by light filters or dyes or additives or fillers.

[0127] (12) The method according to any one of (1), (7) and (11), wherein the light filter comprises one of the group consisting of a UV cut-off filter, a blue cut-off filter and an NIR cut-off filter, wherein the dye comprises one of the group consisting of a color balancing dye, a color enhancing dye, a photochromic dye and a dichroic dye, wherein the additive comprises one of the group consisting of a plasticizer, a heat stabilizer, a light stabilizer, a flow improver and a release agent, and wherein the filler comprises one of the group consisting of particles, fibers and nanotubes.

[0128] (13) A thermoplastic film for an ophthalmic lens formed on an optical mold, the thermoplastic film comprising: a first layer of thermoplastic film formed on the optical mold, wherein the temperature of the optical mold is adjusted to a first temperature during the formation of the first layer of thermoplastic film; and a second layer of thermoplastic film formed on the first layer, wherein the temperature of the optical mold is adjusted to a second temperature during the formation of the second layer of thermoplastic film.

[0129] (14) The thermoplastic film of the ophthalmic lens according to (13) further includes one or more optical surface features, including spherical, non-spherical, bifocal, trifocal, progressive, microlens, Fresnel structure and moth-eye structure.

[0130] (15) An optical mold structure for forming a thermoplastic film, the optical mold structure comprising: a temperature control circuit system that controls one or more electrically heating elements and / or microfluidic channels; an optical mold on the temperature control circuit system for forming a first layer and a second layer of the thermoplastic film, wherein the optical mold further comprises one or more optical surface features, including spherical, non-spherical, bifocal, trifocal, progressive, microlens, Fresnel structure and moth-eye structure; and a vacuum device attached to the optical mold for holding the thermoplastic film on the optical mold.

[0131] By providing the features disclosed herein, thermoplastic layers or films can be printed using an optical mold controlled by a temperature control unit. This differs from existing systems, where temperature cannot be controlled, resulting in lower quality thermoplastic layers or films.

[0132] The foregoing discussion has only disclosed and described exemplary embodiments of the invention. As those skilled in the art will understand, the invention may be practiced in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the disclosure of this invention is intended to be illustrative and not to limit the scope of the invention and the other claims. This disclosure (including any readily identifiable variations of the teachings herein) partially defines the scope of the terms of the preceding claims, leaving no inventive subject matter open to the public.

Claims

1. A method for printing a thermoplastic film on an optical mold, the method comprising: The temperature of the optical mold is adjusted to a first temperature by a temperature control circuit system; Once the temperature of the optical mold reaches the first temperature, the first layer of the thermoplastic film is printed on the optical mold; A vacuum is applied to the optical mold to hold the thermoplastic film on the optical mold and to deform the thermoplastic film to conform to the curvature or microstructure of the surface of the optical mold; The temperature of the optical mold is adjusted to a second temperature by the temperature control circuit system. Once the temperature of the optical mold reaches the second temperature, the second layer of the thermoplastic film is printed on the first layer of the thermoplastic film; The temperature of the optical mold is adjusted to a third temperature by the temperature control circuit system. Once the temperature of the optical mold reaches the third temperature, the first and second layers are annealed. as well as The vacuum is removed from the optical mold, thereby allowing the removal of the thermoplastic film, comprising an annealed first layer and an annealed second layer, from the optical mold.

2. The method according to claim 1, wherein, The first temperature is between 10°C below the glass transition temperature of the thermoplastic film and 30°C above the glass transition temperature of the thermoplastic material of the first layer.

3. The method according to claim 1, wherein, The first layer of the thermoplastic film is a thermoplastic surface layer comprising multiple thermoplastic layers, wherein the thickness of the first layer of the thermoplastic film is between 10 micrometers and 500 micrometers.

4. The method according to claim 1, wherein, The second temperature is equal to or higher than the glass transition temperature of the thermoplastic material in the second layer.

5. The method according to claim 1, wherein, The third temperature is between the glass transition temperature of the thermoplastic material in the second layer and 60°C below the glass transition temperature of the thermoplastic material in the second layer.

6. The method according to claim 1, wherein, The temperature control circuit system controls one or more electric heating elements and / or a microfluidic channel circulated with temperature-adjusting fluid to adjust the temperature of the optical mold.

7. The method according to claim 1, wherein, Printing the first layer or printing the second layer includes printing using a single thermoplastic or at least two different thermoplastics to form a 2D or 3D structure and / or function.

8. The method according to claim 7, wherein, At least one of the at least two different thermoplastics has a higher mechanical strength than the other of the at least two different thermoplastics, and / or at least one of the at least two different thermoplastics has a higher glass transition temperature than the other of the at least two different thermoplastics.

9. The method according to claim 7, wherein, The at least two different thermoplastics form a homogeneous or heterogeneous structure and / or have one or more functions.

10. The method according to any one of claims 7 and 9, wherein, The at least two different thermoplastics form a heterogeneous structure and / or have one or more functions, wherein the difference in refractive index (RI) between the different thermoplastics is less than 0.01, and / or wherein the difference in ΔE between the different thermoplastics is less than 1. It is the CIE76 color difference formula.

11. The method according to claim 7, wherein, The at least two different thermoplastics can be modified with light filters, dyes, additives, or fillers.

12. The method according to claim 11, in, The light filter includes one of the group consisting of a UV cutoff filter, a blue cutoff filter, and an NIR cutoff filter. The dye includes one of the following groups: color balancing dyes, color enhancing dyes, photochromic dyes, and dichroic dyes. The additives include one of the group consisting of plasticizers, heat stabilizers, light stabilizers, flow improvers, and release agents. The filler comprises one of the group consisting of particles, fibers and nanotubes.

13. An optical mold structure for forming a thermoplastic film, the optical mold structure comprising: A temperature control circuit system that controls one or more electric heating elements and / or microfluidic channels; The optical mold on the temperature control circuit system is used to form the first and second layers of the thermoplastic film by printing on the optical surface of the mold structure, wherein the optical mold further includes one or more optical surface features, including spherical, non-spherical, bifocal, trifocal, progressive, microlens, Fresnel structure and moth-eye structure; as well as A vacuum device attached to the optical mold, the vacuum device being used to hold the thermoplastic film on the optical mold and to deform the thermoplastic film to conform to the curvature or microstructure of the surface of the optical mold.

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