Method for designing and manufacturing a planar device

Abstract

There is provided a method for designing a planar device comprising a carrier layer having an outer radius (RCout) and a carrier layer width (WC), a support layer having a support layer width (WS), a distance between an inner edge of the carrier layer and an inner edge of the support layer being (GAP), the method comprising obtaining predetermined values of RCout, WS and GAP; obtaining the geometrical shape of the mold; obtaining material characteristics of the supporting layer and the carrier layer; performing at least two simulations of thermoforming the planar device into a non-planar device based on the obtained predetermined values, the material characteristics and the geometry of the mold; determining a circumferential strain at an outer edge of a support layer of the simulated non-planar device; determining a linear relationship between the circumferential strain and a dimensional ratio defined by ratio = (WC-(WS + GAP)) / RCout based on the determined circumferential strain; determining a value of the dimensional ratio when the strain is zero based on the determined linear relationship; and determining the width of the carrier layer as WC = ratio * RCout + WS + GAP according to the dimensional ratio when the strain is zero.

Description

Technical Field

[0001] The present disclosure relates to methods for designing and manufacturing a planar device that is to be thermoformed into a non-planar device. Background Art

[0002] When a circular shape is formed into a spherical shape with free boundary conditions at the edges by thermoforming or other methods, the geometry experiences negative strain (compression) in the circumferential direction. In the radial direction, the strain remains zero. The circumferential strain can vary from zero in the center to a maximum level at the outer edge. This compressive strain may cause material compression of the geometry and, depending on the choice of material, may cause wrinkling or bending. Some materials cannot accommodate compressive stresses, such as thermosets, rigid materials, and thin layers. For such materials, wrinkles may cause material damage such as cracks, delamination, and ultimately failure.

[0003] One implementation in which a circular shape can be formed into a spherical shape is in the manufacture of contact lenses, particularly smart contact lenses. Smart contact lenses can include a smart platform that includes at least a portion of the functionality of the smart contact lens. The smart platform can include functional components, such as electrical components and thin-film electrical connectors. Functional components can be sensitive to compression and strain. Small wrinkles in the material can translate into wrinkles on the functional component, which can cause the component to break or weaken.

[0004] In some existing solutions, the components are embedded in a thermosetting flat material to protect the components. The thermosetting material is then glued to the contact lens material (such as soft silicone) and pressed together with the contact lens material. Since the thermosetting material is not compressible, wrinkles usually appear on the thermosetting material layer. Further, it may be difficult to align and center the thermosetting material with the contact lens material, and therefore may make this solution unsuitable for large-scale production.

[0005] Other existing solutions deposit components directly onto a flat thermoplastic material that is thermoformed into a non-planar device. However, in such solutions, since the component is incompressible, the component itself may wrinkle or even be damaged by the strain caused by thermoforming. Such wrinkles may cause the component to crack and compromise its functionality.

[0006] Therefore, novel approaches to minimize strain and wrinkling of sensitive materials in non-planar devices are needed. Summary of the invention

[0007] It is therefore an object of the present disclosure to overcome at least some of the above-mentioned disadvantages and to provide a method of designing a planar device to be thermoformed into a non-planar device that minimizes strain on the non-compressive material.

[0008] According to one aspect of the present disclosure, a method for designing a planar device to be thermoformed into a shape-retaining non-planar device using a mold. The planar device includes two concentric annular layers, namely a carrier layer and a support layer. The carrier layer has an outer radius (R Cout ) and carrier layer width (W C The support layer has a support layer width (W S ). The support layer is mechanically attached to the carrier layer. An inner distance (GAP) is formed between the inner edge of the carrier layer and the inner edge of the support layer. The method includes obtaining predetermined values ​​for the outer radius of the carrier layer, the support layer width and the inner distance, obtaining the geometry of the mold and obtaining material properties of the support layer and the carrier layer. The method further includes performing at least two simulations of thermoforming a simulated planar device into a non-planar device using the mold for at least two different carrier layer widths based on the obtained predetermined values, material properties and geometry of the mold. The method further includes determining the circumferential strain at the outer edge of the support layer in each of the simulated non-planar devices. In addition, the method includes determining a linear relationship between the circumferential strain and the dimensional ratio defined by the following equation based on the determined circumferential strain

[0009] Ratio = (W C -(W S +GAP)) / R Cout .

[0010] Based on the determined linear ratio, the method further includes determining a value of the dimensional ratio when the strain is zero. Based on the dimensional ratio when the strain is zero, the method further includes determining a width of the carrier layer in the planar device as

[0011] W C =Ratio*R Cout +W S +GAP.

[0012] Embodiments of the first aspect of the present disclosure provide a method for designing a planar device to be thermoformed into a non-planar device.The method according to the present disclosure may be performed by a processing unit or a computer.

[0013] Specifically, the planar device includes an annular support layer concentrically arranged on an annular platform layer. The design process can determine the optimal position and size of the support layer relative to the carrier layer to avoid compressive stress and wrinkling of the support layer at the periphery of the device. In other words, the method can enable the selection of where to place the carrier layer in the radial direction of the support layer to avoid or at least reduce wrinkles.

[0014] The platform layer may be made of a stretchable material. The support layer may be made of a less stretchable material or a non-stretchable material. More specifically, the material of the support layer may have a higher Young's modulus than the material of the carrier layer. When mechanically attached to or embedded in the carrier layer, the support layer may act as a stress modulator.

[0015] The inventors have recognized that along the radial direction of a non-planar device formed by a planar device, there are points where the circumferential strain is zero. By connecting all these points for all possible radial directions, a curve (or boundary) is formed where the circumferential strain is zero. Hereinafter, this curve may be referred to as the meridian neutral boundary or MNB. By determining the location of this boundary, a planar device can be designed so that the support layer is placed in a region that is not subjected to compressive strain when converted into a non-planar device.

[0016] Using the determined carrier layer width (W C ) together with the obtained outer radius of the carrier layer, the support layer width and the inner distance, the dimensions of the carrier layer and the support layer of the planar device can be determined. Using these values, the outer edge of the support layer can be placed at the MNB, where the calculated circumferential strain is zero. Since the outer edge of the support layer is arranged at the MNB, the support layer will be arranged on the inner side of the boundary formed by the MNB, where the strain is positive when the planar device is thermoformed using a mold. Therefore, the design method of the first aspect can reduce the risk of wrinkling in the support layer.

[0017] MNB is an abstraction of the concept of the neutral plane (NP). The neutral plane is a conceptual strain-free plane along the thickness of a material or a mixed stack of materials. When a sheet or stack of materials is loaded with a bending force, the material or stack is bent. The inner surface of the material / stack is subjected to compression (negative strain) while the outer surface is subjected to tension (positive strain). The neutral plane defines the boundary between the portion of the material / stack that is in compression and the portion of the material / stack that is in tension. In a single sheet of material, the neutral plane is located exactly in the middle of the thickness of the material. However, when different materials are used in stacks, the location of the neutral plane depends on the material properties and the thickness of the materials used.

[0018] The inventors have recognized that when a flat annular device is thermoformed into a non-planar device, the MNB defines a location along the radius of the non-planar device that is neither subject to compression nor tension in the circumferential direction. Inside the MNB, the non-planar device will experience positive strain in the circumferential direction, while outside the MNB, the non-planar device will experience negative strain in the circumferential direction. Similar to the neutral plane, the location of the MNB is affected by the material properties of the materials in the planar device (i.e., the material of the carrier layer and the material of the support layer). The location of the MNB is further affected by the width of each of the annular layers and their relative positions and sizes.

[0019] The present disclosure provides a method for determining the meridional neutral boundary (MNB) by calculating the circumferential strain along the radial direction of different computer simulated non-planar devices.

[0020] The inventors further recognized that the ratio:

[0021] Ratio = (W C -(W S +GAP)) / R Cout

[0022] The ratio has a linear relationship with the circumferential strain. Based on at least two different (computer) simulations of non-planar devices using different carrier layer widths, a linear relationship between the ratio and the circumferential strain can be determined. From the linear relationship, the value of the ratio when the circumferential strain is zero can be found. Based on this value, the relative size of the carrier layer and the support layer can be determined to minimize the compressive strain applied to the support layer when the planar device is thermoformed into the non-planar device.

[0023] The outer radius of the carrier layer, the support layer width, and the inner distance between the inner edge of the carrier layer and the inner edge of the support layer are design parameters that can be defined based on the non-planar device to be produced. For example, in an embodiment where the non-planar device is a platform for a smart contact lens, the outer radius of the carrier layer can be determined based on the preferred size of the contact lens. The support layer width can be selected so that the support layer can accommodate at least one component of the non-planar device. The inner distance can be determined so that the carrier layer can at least partially surround the inner edge of the support layer.

[0024] The step of obtaining information (such as predetermined values ​​and / or geometry of the mold) may include loading said information by a processing unit or computer from a computer-readable storage medium, cloud storage, etc. Alternatively or additionally, the step of obtaining information may include receiving information from a user via a human-machine interface.

[0025] The method according to the present disclosure can achieve the thermoforming of a platform (planar device) from a circular to a spherical (or other non-flat) geometry while avoiding or at least reducing the compressive stress / strain on the relevant materials / components (mainly the materials / components located along the outer edge of the circular shape). By reducing the compressive stress / strain, the method according to the present disclosure can provide a non-planar device with no wrinkles or at least reduced wrinkles along the circumferential direction. Therefore, the mechanical integrity of fragile and thin film components in or on the non-planar device can be protected.

[0026] In the specific example of a smart contact lens, a method according to the present disclosure may allow the electronic platform to be thermoformed (and / or otherwise formed) before being integrated onto or into a contact lens without wrinkles at the outer edge. The method may facilitate alignment of the electronic platform relative to the contact lens, control of the curvature of the contact lens, and embedding of the electronic platform in the contact lens, and make the manufacturing process more compatible with industrial processes for mass production.

[0027] The annular shape of the planar device reduces the negative strain (compression) in the resulting non-planar device compared to a disk with the same radius.

[0028] The present approach utilizes a carrier layer to which the support layer is mechanically attached to optimize the compressive strain at the support layer. According to some embodiments, the support layer may include thin film interconnects, antennas, and electronic components.

[0029] Furthermore, the present solution may allow for an uninterrupted design. In other words, the assembly may extend all the way around the support layer (eg in a closed loop) without experiencing wrinkling.

[0030] According to some embodiments, the material properties include a thickness of the support layer, a thickness of the carrier layer, and mechanical properties of the support layer and the carrier layer.

[0031] As with the neutral plane, the location of the MNB may depend on the material mechanical properties of the material in the planar device as well as the thickness of the material.

[0032] According to some embodiments, the support layer may include a thermoset material.

[0033] Thermosets have a high Young's modulus and a greatly reduced ability to compress or stretch. These properties ensure mechanical protection of the functional components embedded in the support layer. Furthermore, as the name implies, once a thermoset is cured, its shape is fixed. Once hardened, thermosets cannot be reshaped by melting.

[0034] For example, the support layer may include thin film polyimide (PI), epoxy resin, or polyester resin.

[0035] According to some embodiments, the carrier layer may include a thermoplastic material.

[0036] Thermoplastic materials, on the other hand, can be reshaped by thermoforming, melting, pressing, or injection molding.

[0037] For example, the carrier layer may include thermoplastic polyurethane (TPU), polycarbonate (PC), polylactic acid (PA) and / or polyethylene terephthalate (PET).

[0038] The support layer may have a Young's modulus that is significantly higher than that of the carrier layer. When a force is applied to a planar device or a non-planar device, the carrier layer may stretch instead of the support layer because the carrier layer is more flexible. For example, the Young's modulus of the support layer may be 100 times that of the carrier layer. More specifically, the Young's modulus of the support layer may be 150 times, or even 200 times that of the carrier layer.

[0039] For example, the Young's modulus of TPU is 0.04 GPa, while the Young's modulus of PI is 8.3 GPa, which is more than 200 times.

[0040] According to some embodiments, the support layer includes at least one electrical component.

[0041] The support layer can mechanically protect the electrical components.

[0042] For example, the support layer may include electrical interconnects, such as thin film gold interconnects. The support layer may include an antenna, such as a thin film gold antenna. The antenna may be a radio frequency (RF) loop antenna. The RF loop antenna may include a plurality of gold-plated rings. Further, the support layer may include a silicon (Si) component, such as a silicon chip. Such a silicon chip may include an application specific integrated circuit (ASIC), a capacitor, and / or a battery.

[0043] For example, gold interconnects and / or (gold) RF antennas may be embedded inside the support layer. Other components, such as chips, may be positioned and connected on top of the support layer, or embedded inside the support layer. The support layer may be made of a material that requires curing, such as a thermosetting material, which typically occurs at high temperatures, such as 400°C. Not all components can withstand such high temperatures. In such embodiments, such components may be better placed and connected on top of the support layer.

[0044] For example, RF antennas made of gold-plated rings can be used in smart contact lenses. Interconnects between electrical components can be made of sputtered gold, which can only withstand very small stretches before breaking, such as less than 1%. For such devices, it is important to know where to place the non-stretchable support layers, including the antenna, to avoid wrinkling.

[0045] According to some embodiments, the method may further include performing a first simulation on the first carrier layer width and performing a second simulation on the second carrier layer width. The first carrier layer width may be less than 0.15*R Cout , i.e. less than 15% of the outer radius of the carrier layer. The width of the second carrier layer may be greater than 0.3*R Cout , i.e. greater than 30% of the outer radius of the carrier layer.

[0046] Performing simulations for a first, narrower width of the carrier layer and for a second, wider width of the carrier layer may cause the resulting strain and ratio values ​​of the respective simulations to be relatively far apart, and thus a linear relationship determined based on the respective strain and ratio values ​​may be more accurately defined.

[0047] According to some embodiments, the simulation may be a finite element method (FEM) simulation.

[0048] FEM simulation can allow modeling of complex configurations of materials with stacked parts and different geometries. FEM simulation can further allow selection of different material properties, such as viscoelastic properties, elastic properties, and hyperelastic properties. In addition, FEM simulation can facilitate modeling of boundary and contact conditions, such as friction and contact surfaces between the mold and the structure to be thermoformed.

[0049] According to some embodiments, the inner radius of the carrier layer may be at least 3 mm.

[0050] A wearable optical device, such as a (smart) contact lens, may have an optical zone through which light passes to enter the wearer's pupil. In a wearable optical device, it is desirable not to place components in the optical zone as they may interfere with the wearer's vision. In embodiments where the non-planar device is a smart platform for a contact lens, limiting the inner radius to at least 3 mm may ensure that any components in the smart platform do not interfere with the optical zone.

[0051] According to some embodiments, the mold may be a spherical mold.

[0052] The spherical mold can be used to shape a wearable optical device, such as a (smart) contact lens. For example, the mold can be a spherical mold with a radius of 6 mm to 10 mm, such as an 8 mm radius.

[0053] The mold may be in the shape of a spherical cap. Alternatively, the mold may have a different shape. For example, the mold may have a circular symmetrical shape with a non-constant curvature. The mold may have a first curvature (or radius of curvature) in a central portion of the mold and a second curvature (or radius of curvature) in an edge portion of the mold.

[0054] According to one aspect of the present disclosure, a method for manufacturing a planar device is provided, wherein the planar device is to be thermoformed into a shape-retaining non-planar device using a mold. The planar device includes two concentric annular layers, namely a carrier layer and a support layer. The carrier layer has an outer radius (R Cout ) and carrier layer width (W C The support layer is made of a non-stretchable material and has a support layer width (W S). The support layer is mechanically attached to the carrier layer. An inner distance (GAP) is formed between an inner edge of the carrier layer and an inner edge of the support layer. The method includes determining values ​​for an outer radius of the carrier layer, a support layer width, and an inner distance. The method further includes obtaining a width of the carrier layer using the method of any of the preceding claims. The method further includes: providing a carrier layer of a support layer material having a predetermined outer radius and the obtained support layer width; and providing a support layer of a support layer material having a predetermined support layer width, and an inner radius (R Sin )

[0055] R Sin =R Pout -W P +GAP.

[0056] The method further includes arranging a support layer on the carrier layer to be concentric with the carrier layer and mechanically attaching the support layer to the carrier layer.

[0057] A second aspect of the present disclosure provides a method for manufacturing a planar device designed according to any one of the methods of the first aspect of the present disclosure.

[0058] In the specific example of a smart contact lens, the method according to the second aspect can provide a planar device in the shape of an electronic platform that is thermoformed into a non-planar device before integration into or into a contact lens. These design and manufacturing methods can provide a flat electronic platform that can be thermoformed into a non-planar device without (or at least reducing) wrinkles in the support layer.

[0059] According to some embodiments, the method may further include providing a first carrier layer and a second carrier layer, arranging a support layer between the first carrier layer and the second carrier layer, and mechanically attaching the first carrier layer, the support layer and the second carrier layer together.

[0060] In such embodiments, the support layer may be embedded between two carrier layers. In other words, the support layer may be embedded in the carrier layer. It will be understood that in such embodiments, the planar device that is thermoformed into a simulation of a non-planar device also includes a first carrier layer and a second carrier layer.

[0061] The first carrier layer and the second carrier layer can be made of the same material. The first carrier layer and the second carrier layer can have the same thickness and / or size. When the support layer is embedded between two carrier layers of the same thickness, the support layer can be located in the neutral plane (NP) in the stack formed by the carrier layer and the support layer. This can further prevent the stretching or compression of the support layer. Further, the two carrier layers can form a barrier to protect the support layer and any components thereon.

[0062] According to some embodiments, mechanically attaching may include laminating the support layer to the carrier layer.

[0063] In embodiments comprising a first carrier layer and a second carrier layer, the mechanical attaching may comprise lamination attaching the first carrier layer, the support layer and the second carrier layer together.

[0064] According to some embodiments, the method may further include providing at least one electrical component, embedding the at least one electrical component in the support layer.

[0065] According to a third aspect of the present disclosure, there is provided a method for manufacturing a non-planar device that maintains a shape. The method includes providing a planar device according to any one of the embodiments of the second aspect of the present disclosure. The method further includes using a mold to thermoform the planar device into a non-planar device that maintains a shape.

[0066] A third aspect of the present disclosure provides a method for manufacturing a shape-retaining non-planar device by thermoforming a planar device manufactured according to any one of the methods of the second aspect of the present disclosure.

[0067] In the example of a smart contact lens, the method according to the third aspect may provide a non-planar electronic platform that may be integrated on or in a (smart) contact lens.

[0068] According to a fourth aspect of the present disclosure, a computer-readable medium is provided, wherein the computer-readable medium comprises instructions, and when the instructions are executed by a processing device, the processing device is caused to perform the steps of the method of the first aspect of the present disclosure.

[0069] It will be understood that the computer-readable medium may alternatively or additionally include instructions which, when executed by a processing device of a manufacturing apparatus or system, cause the processing device of the manufacturing apparatus or system to perform the steps of the method of the second and / or third aspects of the present disclosure.

[0070] This and other objects are achieved by a method for designing a planar device as defined in the appended independent claim. The dependent claims define further embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Exemplary embodiments will now be described in more detail with reference to the following drawings:

[0072] Figure 1 is a schematic diagram of a planar device according to some embodiments;

[0073] Figure 2 shows a cross section of a planar device and a mold according to some embodiments;

[0074] Figure 3illustrates a cross-section of a non-planar device formed by thermoforming a planar device according to some embodiments;

[0075] Figure 4 is a perspective view of a non-planar device formed by thermoforming a planar device according to some embodiments;

[0076] Figure 5 is an illustration of steps for thermoforming a planar device into a non-planar device using a male mold according to some embodiments;

[0077] Figure 6 illustrates a linear relationship between circumferential strain and a defined ratio for a simulated non-planar device according to some embodiments;

[0078] Figure 7 is a schematic diagram of a planar device including an electrical component in the form of an antenna according to some embodiments: and

[0079] Figure 8 illustrates steps of a method for manufacturing a planar device according to some embodiments;

[0080] Fig. 9 is a flow chart illustrating steps of a method for designing a planar device according to some embodiments;

[0081] Fig.10 is a flow chart illustrating steps of a method for manufacturing a planar device according to some embodiments.

[0082] As illustrated in the drawings, the sizes of elements and regions may be exaggerated for illustrative purposes and, therefore, are provided to illustrate the overall structure of the embodiments. Throughout, like reference numerals refer to like elements. DETAILED DESCRIPTION

[0083] Exemplary embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which presently preferred embodiments are shown. However, the present invention may be implemented in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided to achieve thoroughness and completeness, and to fully convey the scope of the invention to the skilled person.

[0084] refer to Figures 1 to 3 , a planar device 100 to be thermoformed into a non-planar device 316 using a mold 214 will be described.

[0085] Figure 1 is a schematic diagram of a planar device 100 , which may be designed according to any one of the methods of the first aspect of the present disclosure and manufactured according to any one of the methods of the second aspect of the present disclosure.

[0086] The planar device 100 includes an annular support layer 104 mechanically attached to an annular carrier layer 102. The carrier layer 102 has a defined inner radius R Cin The inner edge 106 and the outer radius R Cout The carrier layer 102 further has an outer radius R Cout and inner radius R Cin Limited width W C The support layer 104 has a defined inner radius R Sin The inner edge 108 and the outer radius R Sout The support layer 104 further has an outer radius R Sout and inner radius R Sin Limited width W S An inner distance GAP is formed between the inner edges 106 , 108 of the carrier layer 102 and the support layer 104 .

[0087] Figure 2 The planar device 100 and the mold 214 are shown along Figure 1 The mold 214 is a spherical mold that can be used to thermoform the planar device 100 into a non-planar device. Figure 2 As shown, the support layer 104 has a support layer thickness d S , and the carrier layer 104 has a carrier layer thickness d C . Figure 2 It is also illustrated that the support layer 104 may be embedded in the carrier layer 102 .

[0088] Figure 3 A cross section of a non-planar device 316 formed by thermoforming a planar device 100 using a mold 214 is shown. When thermoforming, the planar device 100 is heated to a temperature at which the carrier layer is pliable or formable. The planar device 100 is then pressed into the mold 214 and allowed to cool. Figure 3 2, carrier layer 102 has been thermoformed to follow the shape of mold 214. Support layer 104 also bends slightly to follow the shape of carrier layer 102 and mold 214. However, support layer 104 is less stretchable than carrier layer 102 and can undergo less deformation than carrier layer 104. Figure 4 A perspective view of a similar non-planar device 316 formed by thermoforming the planar device 100 using the mold 214 is shown.

[0089] refer to Figure 2 and Figure 3 The described example uses the female mold 214. Instead of the female mold 214, a male mold 514 may be used. Figure 5The step of thermoforming the planar device 100 into the non-planar device 316 using the male mold 514 is illustrated. In this embodiment, the planar device 100 is pressed onto the mold 514 rather than into the mold 214.

[0090] Additional references Fig. 9 , a method 1000 of designing a planar device 100 to be thermoformed into a non-planar device 316 using a mold 214 will be described.

[0091] The method 1000 includes obtaining an outer radius R for the carrier layer 102 at step 1010. Cout , support layer width W S and predetermined values ​​of the inner distance GAP. As previously mentioned, these values ​​may be design parameters set by a designer or operator based on the intended use of the non-planar device.

[0092] At step 1020, the method 1000 includes obtaining the geometry of the mold 214, 514 to be used when thermoforming the planar device 100. The geometry of the mold can describe the shape and size of the mold. For example, the geometry of the mold can describe that the mold is a spherical mold with a defined radius.

[0093] At step 1030, material properties of the support layer 102 and the carrier layer 104 are obtained. The material properties may include mechanical properties of the materials for the support layer 102 and the carrier layer 104. For example, a model may be used to represent the material properties of the support layer 102 and the carrier layer 104. The support layer 102 may be represented by a viscoelastic model. The carrier layer 104 may be represented by an elastic model. The viscoelastic properties of the support layer may be determined based on dynamic mechanical analysis (DMA) measurements at different strain rates and temperatures. The material properties (or models) may be used to represent the materials of the support layer 102 and the carrier layer 104 during the simulation of thermoforming a planar device into a non-planar device.

[0094] At step 1040, at least two simulations are performed. Each of the simulations uses a mold having the obtained geometry to simulate thermoforming a planar device into a non-planar device. The simulated planar device has an outer radius R based on the obtained predetermined value (i.e., the outer radius R of the carrier layer 102). Cout , support layer width W S and the inner distance GAP) and the obtained material properties of the carrier layer 102 and the support layer 104. However, each of the different simulated planar devices has a different carrier layer width W C .

[0095] At step 1050 , the circumferential strain at the outer edge 110 of the support layer 104 is determined in each of the simulated non-planar devices 316 .

[0096] At step 1060 , the linear relationship between the hoop strain and the dimension ratio is determined by the following equation.

[0097] Ratio = (W C -(W S +GAP)) / R Cout

[0098] The linear relationship is based on the determined circumferential strain and the input values ​​determined for each of the simulations. Since the relationship between the circumferential strain and the determined ratio is linear, two simulations may be sufficient to determine the relationship.

[0099] Now further reference will be made to Figure 6 , which illustrates an example of this linear relationship. Figure 6 The figure shows a plot of the ratio on the horizontal axis and the determined circumferential strain at the outer edge of the support layer on the vertical axis for two different simulations sim1 and sim2. A linear relationship between the circumferential strain and the size ratio has been plotted based on the values ​​of the two simulations sim1 and sim2. The linear relationship can be described as

[0100] Strain = slope * ratio - b

[0101] Where slope is the slope or gradient of the line and b is the strain obtained when the ratio equals zero.

[0102] At step 1070, a value of the dimension ratio at which the strain is zero is determined based on the determined relationship. Figure 6 This is equivalent to determining the ratio value ratio of the points marked as MNB MNB , where the linear relationship intersects the horizontal axis. Based on the above linear relationship, the ratio value when the strain is zero can be expressed as:

[0103] ratio MNP =b / slope.

[0104] In other words, the width W of the carrier layer 102 is determined according to the design method of the present disclosure. C , the width W of the support layer 104 S , internal distance GAP and external radius R Cout For this ratio, the circumferential strain at the outer edge 110 of the support layer 104 will be zero.

[0105] At step 1080, based on the determined ratio value ratio MNB and the predetermined design parameter W S , GAP and R Cout To determine the width W of the carrier layer C for:

[0106] W C =ratio MNB*Rx out +W S +GAP.

[0107] Now further reference will be made to Figure 7 , which illustrates a planar device 700 that may be designed according to any of the methods of the first aspect of the present disclosure and manufactured according to any of the methods of the second aspect of the present disclosure.

[0108] Figure 7 A planar device 700 is shown. The planar device 700 may be identical to the planar device 100, except that the electrical components, specifically the thin film antenna 718, are embedded in the support layer 104.

[0109] Further, in Figure 7 In FIG. 1 , the MNB is indicated by a dotted line. The outer edge of the support layer 104 is arranged at the MNB. Figure 7 In the embodiment of the present invention, the MNB has a circular shape. As described above, when the planar device 700 is thermoformed into a non-planar device, for each radial direction r, there is a point P for which the circumferential strain is neither positive nor negative. Inwardly of the point P, i.e., closer to the center, the circumferential strain is positive. Outwardly of the point P, i.e., further away from the center, the circumferential strain is negative. The MNB includes all points P for all different radial directions r.

[0110] Using the determined carrier layer width W C Together with the design parameters (predetermined values) (ie, the outer radius R of the carrier layer 102 Cout , support layer width W S and the inner distance GAP), the dimensions of the carrier layer 102 and the support layer 104 of the planar device 100, 700 can be determined. Using these values, the outer edge 110 of the support layer 104 will be placed at the calculated MNB, i.e., at the curve where the circumferential strain is zero. In principle, when the planar device is thermoformed into a non-planar device, any component located at a radius smaller than the MNB will experience tensile strain, thereby avoiding wrinkles caused by compressive strain. When the outer edge 110 is arranged at the MNB, the support layer 104 will be arranged on the inner side of the MNB. Therefore, the risk of wrinkling of the support layer 104 can be reduced or avoided.

[0111] Additional references Fig.10 , a method 2000 of manufacturing a planar device 100 to be thermoformed into a non-planar device 316 using a mold 214 will be described.

[0112] Fig.10 is a flow chart illustrating method 2000 . Figure 8 is along Figure 7 2000. It illustrates a cross section taken along line B in FIG.

[0113] The method 2000 includes determining, at step 2010, an outer radius R for the carrier layer. Cout , support layer width W S and the value of the internal distance GAP. As previously mentioned, these parameters can be determined based on the desired size and use of the planar device.

[0114] At step 220, method 2000 includes using the design method according to the first aspect of the present disclosure (such as the design method described above). Fig. 9 The method 1000 described above is used to obtain the width W of the carrier layer 104. C .

[0115] At step 2030, the method 2000 includes providing a carrier layer 102 of a carrier layer material, the carrier layer 102 having a predetermined outer radius R Cout and the obtained carrier layer width W C .

[0116] Alternatively, the method 2000 may include providing the first carrier layer 820 and the second carrier layer 822 at step 2035, such as Figure 8 As shown. The first carrier layer 820 and the second carrier layer 822 both have a predetermined outer radius R Cout and the obtained carrier layer width W C .

[0117] The method 2000 further includes providing a support layer 104 of a support layer material at step 2040. The support layer 104 has a predetermined support layer width W S and the inner radius R determined by Sin

[0118] R Sin =R Pout -W P +GAP.

[0119] In some embodiments, the method includes providing at step 2050 at least one electrical component, such as Figure 7 and Figure 8 The antenna 718 is shown. The method may further include embedding at least one electrical component in the support layer 104 at step 2060.

[0120] At step 2070 , the method includes arranging the support layer 104 and the carrier layer 102 concentrically.

[0121] In an embodiment where a first carrier layer 820 and a second carrier layer 822 have been provided, the method may include, at step 2075, arranging the support layer 104 between the first carrier layer 820 and the second carrier layer 822 such that all three layers are concentric, e.g. Figure 8 shown.

[0122] The method further includes, at step 2080 , mechanically attaching the support layer 104 to the carrier layer 102 , such as by lamination.

[0123] In embodiments where two carrier layers are used, the method may alternatively include attaching together the first carrier layer 820, the support layer 104, and the second carrier layer 822 at step 2085. The support layer 104 may thus be embedded in the carrier layer 824.

[0124] Those skilled in the art realize that the present invention is by no means limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims.

[0125] Although features and elements are described above in particular combinations, each feature or element may be used alone without the other features and elements or in various combinations with or without the other features and elements.

[0126] Furthermore, variations of the disclosed embodiments are understood and accomplished by the skilled person in practicing the claimed invention by studying the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain features are recited in mutually different dependent claims does not indicate that a combination of these features cannot be used to advantage.

Claims

1. A method (1000) for designing a planar device (100) to be thermoformed into a shape-retaining non-planar device (316) using a mold (214), the planar device comprising: Two concentric annular layers: a carrier layer (102) having an outer radius (R Cout ) and carrier layer width (W C ); and a support layer (104) having a support layer width (W S ), the support layer is mechanically attached to the carrier layer, wherein an inner distance (GAP) is formed between an inner edge (106) of the carrier layer and an inner edge (108) of the support layer; the method comprising: obtaining (1010) predetermined values ​​of an outer radius of the carrier layer, a width of the support layer, and the inner distance; obtaining (1020) a geometric shape of the mold; obtaining (1030) material properties of the support layer and the carrier layer; performing (1040) at least two simulations of thermoforming the simulated planar device into a non-planar device using the mold based on the obtained predetermined values, material properties, and the geometry of the mold for at least two different carrier layer widths; determining (1050) a circumferential strain at an outer edge (110) of a support layer in each of the simulated non-planar devices; Based on the determined circumferential strain, determine (1060) the circumferential strain and the ratio = (W C -(W S +GAP)) / R Cout A linear relationship between defined dimensional ratios; Based on the determined linear relationship, the size ratio (ratio) at which the (1070) strain is zero is determined. MNB ) value; The width of the carrier layer in the planar device is determined (1080) to be W according to the dimension ratio when the strain is zero. C =ratio MNP *R Cout +W S +GAP.

2. The method of claim 1, wherein: The material properties include the thickness of the support layer (d S ), the thickness of the carrier layer (d C ), and the mechanical properties of the support layer and the carrier layer.

3. The method of claim 1, wherein: The support layer includes a thermosetting material.

4. The method of claim 1, wherein: The carrier layer comprises a thermoplastic material.

5. The method of claim 1, wherein: The support layer includes at least one electrical component.

6. The method of claim 1, wherein: The performing at least two simulations includes performing a first simulation on a first carrier layer width and performing a second simulation on a second carrier layer width, wherein the first carrier layer width is less than 0.15*R Cout , the width of the second carrier layer is greater than 0.3*R Cout .

7. The method of claim 1, wherein: The simulation is a finite element method FEM simulation.

8. The method of claim 1, wherein: The inner radius of the carrier layer (R Cin ) is at least 3 mm.

9. The method of claim 1, wherein: The mold is a spherical mold.

10. A method of manufacturing a planar device (100) to be thermoformed into a shape-retaining non-planar device (316) using a mold (214), the planar device comprising two concentric annular layers: a carrier layer (102) having an outer radius (R Cout ) and carrier layer width (W C ); and a support layer (104) having a support layer width (W S ), the support layer is mechanically attached to the carrier layer, wherein, forming an inner distance (GAP) between an inner edge (104) of the carrier layer and an inner edge (106) of the support layer; the method comprising: determining (2010) values ​​of the outer radius of the carrier layer, the support layer width, and the inner distance; Obtaining (2020) the width of the carrier layer by performing the method of any one of the preceding claims; providing (2030) a carrier layer of a carrier layer material, the carrier layer having a predetermined outer radius and a resulting carrier layer width; Providing (2040) a support layer of a support layer material, the support layer having a predetermined support layer width and a support layer composed of R Sin =R Pout -W P +GAP determines the inner radius (R Sin ); disposing (2070) the support layer on the carrier layer to be concentric with the carrier layer; and The support layer is mechanically (2080) attached to the carrier layer.

11. The method of claim 10, further comprising: Providing (2035) a first carrier layer and a second carrier layer; as well as disposing (2075) the support layer between the first carrier layer and the second carrier layer; The first carrier layer, the support layer and the second carrier layer are mechanically (2085) attached together.

12. The method of claim 10, wherein: The mechanical attachment comprises laminating the support layer to the carrier layer.

13. The method of claim 10, further comprising: providing (2050) at least one electrical component; as well as The at least one electrical component is embedded (2060) in the support layer.

14. A method of making a shape-retaining non-planar device (316), the method comprising: Providing a planar device (100) according to the method of claim 10; as well as The planar device is thermoformed into a shape-retaining non-planar device using a mold (214).

15. A computer readable medium comprising instructions which, when executed by a processing device, cause the processing device to perform the method of any one of claims 1 to 9.

Images