Improvements in lenses

Abstract

A method for forming a polymer is disclosed. The method includes: positioning a mold relative to a molten pool containing a molten material to form a mold cavity between the mold and the molten material; adding a monomer into the mold cavity; and solidifying the monomer to form a polymer.

Description

Technical Field

[0001] The present invention relates to improvements in the manufacture and evaluation of lenses. More particularly, the present invention relates to lenses formed using a single material cast between two forms. Background Art

[0002] Lens formation can be a complex process. This is particularly true when using films or foils such as PMMA, and cast lens materials such as UV-curable monomers to form lenses in a laminated manner. The method disclosed in WO 2018 / 087011 A1 can be applied to produce cast lenses with embedded films. Known processes for lens formation are limited to casting between two solids, or between a solid and a gas (e.g., air) or a vacuum. This process has a number of disadvantages, which the present application aims to overcome. Summary of the invention

[0003] According to a first aspect, there is provided a method for forming a polymer, the method comprising:

[0004] positioning the mold relative to a melt pool containing molten material;

[0005] adding material between the mold and the melt pool; and

[0006] The material is cured to form a polymer.

[0007] Thus, the present invention provides an improved method for forming a polymer which enhances the surface finish of one surface of the polymer.It is contemplated that the term "mold" may include not only molds which are not intended to be part of the final product and are thus discarded, but also substrates which are intended to be part of the final product.

[0008] The method may further include the step of solidifying at least a portion of the molten material after the monomer solidifies. The at least a portion of the molten material may solidify to form a handle, a holder, or a protective housing. By solidifying a portion or all of the molten material, the polymer may be more easily transported with or without attachment to a mold. For example, the solidified material may provide protection and / or rigidity to the polymer.

[0009] The mold may be positioned using a floatation device that is supported by the molten material and configured to hold the mold in a set position relative to the molten material. The use of a floatation device ensures that the mold is held horizontally relative to the surface of the molten material and at a desired angle set by the connection between the mold and the floatation device. The floatation device may be toroidal or annular. Alternatively, the floatation device may take any other shape.

[0010] The floatation device may be rigidly connected to the mould and may form part of the mould. For example, the floatation device may form one or more walls of the mould, such as side walls, while the mould forms other walls, such as an upper wall interconnecting the side walls. The mould and the floatation device may be integrally formed as one component.

[0011] The position of the mold may be adjustable relative to the floatation device. The mold may be movably connected to the floatation device so that a user can adjust the position of the mold relative to the floatation device. Thus, while the floatation device remains fixed relative to the molten material, the mold may be moved relative to the molten material to change the shape and / or size of the mold cavity (i.e., the space between the mold and the molten material). For example, the shape and size may be changed by changing the vertical distance between the mold and the molten material or by changing the angle of the mold relative to the molten material. Adjustability may be provided by any form of adjustment device, including, for example, a movable joint such as a ball joint, a hinge, a slider, a ratchet, etc.

[0012] The method may further comprise the step of adjusting the position of the floatation device relative to the molten material by adding ballast to the floatation device or removing ballast therefrom. This may be considered as part of the step of positioning the mould relative to the molten material. The ballast may be applied uniformly to the floatation device so as to raise or lower the floatation device in the molten material, i.e. to adjust its overall buoyancy. Alternatively, the ballast may be applied unevenly to the floatation device so as to change the orientation of the floatation device relative to the molten material, i.e. to adjust its local buoyancy.

[0013] The step of adding monomer can be performed through ports in the mold and / or floatation device. Adding monomer through the ports allows the monomer to be added while the mold cavity is in its desired position relative to the molten material. The mold can be tilted while the monomer is added. Where a floatation device is also used, the mold and / or floatation device can be tilted. This can help avoid bubbles or air gaps in the mold cavity. For example, tilting the mold can allow monomer to be added to a port that is tilted to a lower position than its resting position while allowing air or gas in the mold cavity to escape through a port that is tilted to a higher position than its resting position.

[0014] The method may further include the step of forming a surface pattern on the molten material before the monomer solidifies. By forming a pattern on the surface of the molten material, the pattern can be transferred to the monomer when the monomer solidifies, thereby making a pattern on the solidified polymer. The surface pattern can be formed by an ultrasonic transmitter. The ultrasonic transmitter can be applied so that the ultrasonic transmitter guides ultrasonic waves through the molten material, and the ultrasonic transmitter can be positioned, for example, at the edge of the molten pool.

[0015] The method may further include the step of embedding an object in the monomer prior to curing. The object may be embedded on the surface of the monomer, or the object may be embedded within the monomer. The object may be positioned by one or more spacers. For example, the object may be a foil, a holographic element, a decorative element (e.g., jewelry, a logo, etc.), an electronic component, or other such object.

[0016] The method may further comprise the step of positioning a second mould prior to solidification of the monomer, the second mould defining a mould cavity, the second mould being supported by the molten material.Using a second mould may allow a wider variety of polymer shapes to be formed.

[0017] According to a second aspect of the present invention, there is provided a system for forming a polymer, the system comprising:

[0018] a molten pool comprising molten material; and

[0019] A mold is positioned relative to the molten pool so as to form a mold cavity between the mold and the molten material for receiving the monomer.

[0020] The system may further include a flotation device supported by the molten material and configured to hold the mold in a set position relative to the molten material.

[0021] The position of the mould may be adjustable relative to the flotation device.The flotation device may comprise a support structure comprising one or more joints to allow the position of the mould to be adjusted.

[0022] The system may further include ballast movable to adjust the position of the flotation device relative to the molten material.

[0023] The mould and / or the floatation device may include ports for adding monomer.

[0024] The system may further include a device configured to form a surface pattern on the molten material. The device may include an ultrasonic transmitter.

[0025] The system may further include a second mold defining a mold cavity, the second mold being supported by the molten material. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Specific embodiments will now be described in detail with reference to the accompanying drawings, in which:

[0027] Figure 1 is a schematic diagram of a first assembly for molding a lens;

[0028] Figure 2 is a flow chart of a method for molding a lens;

[0029] Figure 3is a schematic diagram of a second assembly for molding a lens;

[0030] Figure 4 is a schematic diagram of a third assembly for molding a lens;

[0031] Figure 5 is a schematic diagram of a fourth assembly for molding a lens, including surface patterning;

[0032] Figure 6 is a schematic diagram of a fifth assembly for molding a lens, including embedding an object into a surface of the lens;

[0033] Figure 7 is a schematic diagram of a sixth assembly for molding a lens, including embedding an object into the lens; and

[0034] Figure 8 is a schematic diagram of a seventh component for molding a lens. DETAILED DESCRIPTION

[0035] A known method for forming a polymer lens utilizes two super-polished molds aligned together, these molds are usually made of glass but (in the case of heat curing) can also be made of carbide or the like. Liquid monomer can be injected between the molds and then hardened using UV radiation to form the lens. When using this process, separating the lens from the mold is a known problem, as pointed out in the previous content. In particular, separating the mold from the lens may cause deformation of the lens or may damage the mold and / or the lens. Since polishing is generally an expensive process, the mold is usually quite high in price considerations. The method described below reduces the number of polishing molds required by one-half.

[0036] The described method may be advantageous for casting products using the described method when at least one side is a flat side and / or forming a single body without embedded objects in or on the surface (such as foils, holographic elements, jewelry, logos, electronic devices). The disclosed method may also be used to cast something on a substrate (mold) when the substrate (mold) is not intended to be removed, such as in surface coating or lamination.

[0037] In particular, the described method can be used to form plano-convex lenses, plano-concave lenses or biplanar lenses, or to laminate such layers on UV transparent substrates, with several advantages. Furthermore, not only flat lenses can be achieved, but also certain patterns.

[0038] While the present method may be viewed as similar to float glass production, in which a molten metal such as tin is used as a high surface quality support for the molten glass, known float glass production methods are not suitable for use with organic polymers that are typically used to produce optical devices. This is due at least in part to the high temperatures involved, which can easily damage the organic material and / or cause polymerization earlier than desired.

[0039] The disclosed method for forming a lens includes using a low melting point metal, alloy or other material to form a molten weld pool 102 on which the lens can be formed, such as Figure 1 and Figure 2 As shown. Example low melting point materials include Woods metal, Fields metal, Cerrolow RTM, gallistan and NaK. Other materials (such as mercury) may also be suitable, but these materials may have disadvantages such as high toxicity. By using this method, the required molds can be reduced. The provided method can even eliminate the use of a top mold, so that the lens is easily formed on the surface of the molten melt pool. The molten melt pool can be used in combination with a UV-curable monomer or a heat-curable monomer to obtain at least one good quality surface on the side of the resulting cured sample that is in contact with the molten material.

[0040] The softness of the molten metal pool even allows fragile objects to be cast onto the substrate (i.e., top mold) even when the substrate is too soft or fragile to withstand traditional demolding processes. In one example, the polymer material may be only 200 microns thick and 85 mm in diameter, making it fragile. The same applies when it is desired to laminate a fragile material onto a lens, for example, where removing both molds could result in damage when it is unclear which mold to remove first.

[0041] Figure 1 An assembly 100 is shown, and Figure 2 A flow chart outlining the method is shown. A mold 104 may be positioned S10 relative to a molten pool 102, and then a monomer 106 may be filled S12 between the molten pool 102 and the mold 104, whereupon the monomer 106 may be cured S14, for example by applying UV light or by increasing temperature (thermal curing). After curing, the monomer 106 will be referred to as a sample. Figure 1The assembly 100 also includes spacers 108 that are used to enclose the sides of the monomer 106 and ensure the correct spacing between the surface of the molten pool 102 and the mold 104. In some cases, it may also be desirable to use an inert gas atmosphere and / or remove impurities or oxides from the surface of the molten metal before filling the mold cavity 110 with the monomer. After solidification, any conventional method can be applied to remove the lens, i.e., the solidified monomer 106, from the mold 104. Alternatively, the metal 112 that constitutes the molten pool 102 can be cooled to allow better demolding on the mold side. For example, by cooling the metal until it solidifies S16, the metal can hold the solidified sample so that it can be removed from the mold (i.e., by forming a handle) S18. After removal, the metal can be reheated to allow the sample to be easily removed from the metal S20. After removing the sample, the metal 112 can be cleaned to allow it to be used again.

[0042] The step of solidifying the metal 112 after the sample is solidified has a variety of benefits. For example, the solidified metal can be used as a grip or handle to make the sample easier to remove. For example, this can allow the mold 104 to be easily removed from the other side of the sample, or can be used as protection for sample transportation or downstream processing of the sample. This may be particularly useful if the sample is thin or fragile after solidification.

[0043] As a side note to this, it should be noted that certain metals that may be used for the molten weld pool 102, such as bismuth-containing alloys, may expand when cooled or solidified. It should be noted that this volumetric property may be "tuned" to prevent deformation of the sample or to utilize deformation to provide a desired curvature in the sample.

[0044] Normally, during curing, the monomers shrink along with any adhesives used. It is known that stresses are generated within a polymer sample (e.g., a lens in production) and between the sample and the mold. The stresses may cause localized detachment and therefore an uneven surface on the sample. Similarly, metals typically shrink as they cool and solidify. By using a metal that does not act in this normal way, the method may have the benefit of preventing or limiting the introduction of these stresses.

[0045] These effects can also be used to cause a desired bend in the sample. For example, the expansion of the metal as it cools and solidifies (if designed to do so) can cause the sample to bend. If the opposite side of the sample can then be polished and the sample then released from the metal, the sample can spring back to its original shape, forming the lens shape. This may be desirable in some embodiments.

[0046] In some cases, the side of the lens that is in contact with the molten pool may need to be cleaned by using chemicals or otherwise. This may be particularly advantageous if the material making up the molten pool 102 has an affinity for the surface of the lens, i.e., if the liquid wets the surface of the lens.

[0047] Different arrangements of the mold 104 and the molten pool 102 may be provided, and Figures 3 to 8 Some additional examples are shown.

[0048] Figure 3 An embodiment 200 is shown that utilizes the principle of self-leveling in order to properly form the desired post-curing specimen. The mold 204 is attached to a support structure 214 that includes a flotation device 216 and a plurality of adjustable sections. Figure 3 In the embodiment of the present invention, the floatation device 216 is formed as a toroidal material that floats on the molten metal 112. The support structure 214 includes a height adjustment device 218 and an angle adjustment device 220, which allows the user to adjust the position of the mold 204 relative to the support structure 214, and the fact that the floatation device 216 will always be placed on the surface of the molten pool 202 allows the user to adjust the position of the mold 204 relative to the molten pool 202. In this way, the floatation device 216 ensures that the mold 204 is always held in the desired position to form the desired single sample, that is, the mold 204 and the support structure 214 are self-leveling. Although described as a toroid, the floatation device can take many different shapes. In some embodiments, it may be desirable to form the floatation device as a ring for ease of use and manufacture. However, the floatation device can be a single part (such as a ring) or formed in multiple parts in any other shape.

[0049] from Figure 3 As will be seen in Figure 1, when the mould is in an angled position, part of the mould may be below the surface of the molten metal. This may be undesirable, for example because the mould will have its own buoyancy and may affect the levelness of the flotation arrangement, or may cause some bending of other components, particularly when this arrangement is used in conjunction with a foil or other object to be embedded in the monomer, as described below. In these circumstances, it may be desirable to adjust the part of the mould that protrudes into the molten metal so as to limit the total protrusion of the mould, thereby limiting or preventing these problems.

[0050] Thus, it can be seen that the use of the molten pool 202 in the manufacture of solidified monomer specimens is useful in not only producing a high surface quality on the surface of the specimen facing the molten metal 212, but also allowing the upper mold 204 to be accurately aligned when used with the buoyant flotation device 216. This buoyancy also allows the mold 204 to self-level to a designed angle if desired.

[0051] Figure 4 Another embodiment 300 is shown, which utilizes the self-leveling principle in a manner similar to Figure 3 304. Here, the support structure is replaced with a simpler mechanism in which the mold 304 is directly connected to the floatation device 316, which may also form a part of the mold 304, such as a spacer at the side of the mold cavity. Due to the simpler nature of the assembly 300, the mold cavity 310 can be adapted by changing the floatation characteristics of the floatation device 316. For example, by uniformly adding or removing ballast on the floatation device 316 and / or the mold 304, the floatation device 316 and the mold 304 can be positioned lower or higher in the molten metal 312, respectively. Therefore, the final size of the single body specimen produced by the mold 304 can be adjusted as needed. Similarly, by unevenly adding or removing ballast from the system, such as having more ballast on the left side of the float 316 and less ballast on the right side, the float 316 can be unevenly positioned in the molten pool 304, i.e., some portions of the float 316 will be positioned lower in the molten pool 302 than other portions of the float 316. In this way, the overall thickness and angle of the bottom of the solidified monomer sample can be adjusted by varying the ballast placed on the float 316 and / or the mold 304.

[0052] In some embodiments, the mold can be separated from the floatation device. This may be useful where the upper surface does not need to be molded, or where the floatation device can then be used as a lens holder after curing to hold the cured sample for removal from the molten pool.

[0053] Figure 4 Ports 322 are also shown, which extend through the floatation device 316 to provide access to the mold cavity 310. These ports 322 can be used for venting and / or filling of the mold cavity. In the depicted embodiment, two ports 322 are provided, which are in opposite positions on the mold cavity 310. This arrangement of ports 322, along with other arrangements in which the ports 322 are not adjacent to each other, can provide advantageous effects when one port 322 is used for filling and the other port is used for venting. For example, by angling the floatation device 316 and the mold 304 so that the filling port is lower than the venting port, bubble formation can be limited or prevented. It is also possible to allow the ports to be larger than those that may be used in more common arrangements for forming polymer lenses in other cases. In other embodiments, the monomer can be placed on the molten metal, and then the mold and floatation device are positioned around the monomer so that the monomer can flow into the mold or be sucked into the mold, for example, by surface tension. This can allow the mold to be filled more quickly.

[0054] Figure 5Another embodiment 400 is shown in which a surface pattern can be formed on the surface of the sample on the side of the molten metal 412. The assembly 400 is similar to Figure 1 Components, but additionally include an ultrasonic generator 424, which is used to form a surface wave pattern 426 in the molten metal 412. Other forms of wave generation can also be used, and these other forms of wave generation are known to the technician. In one embodiment, as shown in the figure, the ultrasonic generator 424 transmits a certain frequency so that a standing wave is formed in the top of the molten metal 412. The formation of the standing wave causes a pattern imprint to be produced on the monomer, which can then be cured so that the surface pattern is retained on the sample when it is removed from the mold 404. Of course, by changing the application of ultrasonic waves, such as by changing the frequency, amplitude or phase of one or more ultrasonic heads / generators 424, the surface pattern can be formed into any number of different patterns. This design is known in the art.

[0055] Figure 6 and Figure 7 The illustrated arrangements 500, 600 are also similar to Figure 1 , but additionally includes an object 528, 628 embedded therein after the monomer sample is cured. In the depicted embodiments 500, 600, the object 528, 628 is a foil, but the object 528, 628 may also include other objects, such as a holographic element or other such objects as described above.

[0056] exist Figure 6 In the embodiment of the present invention, the object 528 is positioned on the surface of the molten metal so that the object 528 is present on the surface of the sample after the monomer 506 solidifies. Figure 7 The object 628 in the mold 504, 604 is positioned within the monomer 606 itself. The objects 528, 628 can be positioned so that the objects float freely within or on the monomer 506, 606 before the monomer 506, 606 is cured, or spacers can be used to hold the objects 528, 628 in a desired position within the monomer 506, 606 relative to the mold 504, 604. Of course, no matter which method is used to hold the object, the position can be controlled in both lateral and vertical directions.

[0057] Figure 8Another embodiment 700 is depicted in which two molds 704a, 704b are positioned on molten metal. The larger mold 704a is positioned around the smaller mold 704b, thereby forming a mold cavity 710 enclosed by the molds 704a, 704b and the molten weld pool 702. Each of the molds 704a, 704b includes an integral floatation device so that they are each independently self-supporting on the molten metal 712. In this way, a monomer 706 can be injected between the molds 704a, 704b for forming. The thickness of the monomer 706 can be adjusted by adding or removing ballast (not shown) to one or both of the floatations to adjust the manner in which each floatation device is seated within the molten metal 712. In some embodiments, it may also be desirable to ensure that the smaller mold 704b is accurately positioned within the larger mold 704a by using one or more spacers. This embodiment can also be combined with Figure 6 and Figure 7 Related teachings are incorporated to position a foil or other object on or within cell 706 .

[0058] Of course, although Figure 8 Embodiments of the invention may not reduce the number of molds compared to alternative manufacturing methods, but the other benefits of the invention will still apply.

[0059] While the disclosed method may be particularly useful in situations where the sample is to be removed from a mold, such as in lens manufacturing, the method may also be used in other situations. For example, the method may be utilized to allow the sample to be coated or laminated on a substrate, such as in situations where the mold, as shown, is a substrate that is not intended to be removed. This may be particularly useful in applications such as manufacturing waveguides, microwave circuits, pneumatic / fluid circuits, stamping, etc. For example, when used in conjunction with UV curing, the present technology provides an imaging technique similar to lithography (i.e., printing of complex patterns). In addition, the present technology may allow the final sample to have a better surface finish and greater thickness than using lithography.

[0060] It is obvious that, unless otherwise specifically stated, any one or more features disclosed with respect to one embodiment of the present invention may be used in combination with any one or more features of any other one or more embodiments of the present invention. Figure 3 The self-leveling feature of the embodiment can be used with Figure 6 and Figure 7 The foil positioning of the embodiment and / or Figure 8 As another non-limiting example, any embodiment may be used in conjunction with an additional mold in the embodiment. Figure 5 The surface patterning features of the embodiments are combined. This applies to each embodiment and is not limited to the specific examples disclosed herein.

Claims

1. A method for forming a polymer, the method comprising: Positioning (S10) a mold (104, 204, 304, 404) relative to a molten pool (102) containing molten material to form a mold cavity (110, 310) between the mold (104) and the molten material; Adding (S12) a monomer (106) into the mold cavity (110, 310); and The monomer (106) is cured (S14) to form a polymer. 2 . The method of claim 1 , further comprising the step of solidifying at least a portion of the molten material after the monomer is solidified ( S16 ).

3. The method of claim 2, wherein: The at least a portion of the molten material solidifies to form ( S18 ) a handle, a holder or a protective housing.

4. The method of claim 1, wherein: The mold is positioned using a flotation device (216, 316) supported by the molten material and configured to hold the mold in a set position relative to the molten material.

5. The method of claim 4, wherein: The position of the mold can be adjusted relative to the floating device (216, 316).

6. The method of claim 4, further comprising the step of adjusting the position of the flotation device (216, 316) relative to the molten material by adding or removing ballast from the flotation device (216, 316).

7. The method of claim 4, wherein: The step of adding the monomer is performed through a port (322) in the mold and / or the floatation device (216, 316).

8. The method of claim 7, wherein: The mold and / or the floatation device (216, 316) is tilted while the monomer is added.

9. The method of claim 1, further comprising the step of forming a surface pattern on said molten material before said monomer solidifies.

10. The method of claim 9, wherein: The surface pattern is formed by an ultrasonic transmitter (424).

11. The method of claim 1, further comprising the step of embedding an object in the monomer before curing (S14).

12. The method of claim 11, wherein: The object is embedded on the surface of the monomer or embedded in the monomer.

13. The method of claim 11, wherein: The object is positioned by one or more spacers (108).

14. The method of claim 1, further comprising the step of positioning a second mold before the monomer is solidified (S14), the second mold defining the mold cavity (110, 310), the second mold being supported by the molten material.

15. A system (100, 200, 300, 400, 500, 600) for forming a polymer, the system comprising: a molten pool (102, 302), the molten pool (102, 302) containing molten material; as well as A mold (104, 204, 304, 404) is positioned relative to the molten pool (102, 302) so as to form a mold cavity (110, 310) between the mold and the molten material for receiving a monomer.

16. The system of claim 15, further comprising a flotation device (216, 316) supported by the molten material and configured to hold the mold in a set position relative to the molten material.

17. The system of claim 16, wherein: The position of the mold (104, 204) is adjustable relative to the floatation device (216).

18. The system of claim 17, wherein: The flotation device (216) includes a support structure (214) including one or more joints to allow adjustment of the position of the mold.

19. The system of claim 16, further comprising ballast movable to adjust a position of the flotation device (216) relative to the molten material.

20. The system of claim 16, wherein: The mold and / or the floatation device comprises a port (322) for adding the monomer.

21. The system of claim 15, further comprising a device configured to form a surface pattern on the molten material.

22. The system of claim 21, wherein: The device includes an ultrasonic transmitter (424).

23. The system of claim 15, further comprising a second mold, the second mold defining the mold cavity (110, 310), the second mold being supported by the molten material.

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