CN111813263B

CN111813263B - Thermoformed repair particles and method

Info

Publication number: CN111813263B
Application number: CN202010663326.8A
Authority: CN
Inventors: 许雅筑; 林柏青; 李嘉甄; 余蕙均; 萧靖平
Original assignee: Interface Optoelectronics Shenzhen Co Ltd; Interface Technology Chengdu Co Ltd; General Interface Solution Ltd
Current assignee: Interface Optoelectronics Shenzhen Co Ltd; Interface Technology Chengdu Co Ltd; General Interface Solution Ltd
Priority date: 2020-07-10
Filing date: 2020-07-10
Publication date: 2022-09-20
Anticipated expiration: 2040-07-10
Also published as: TWI757796B; CN111813263A; TW202203253A

Abstract

A method of thermoplastic forming, comprising adding a plurality of repair particles in a laminate, heating the laminate to form a conductive liquid in the inner core of the repair particles, stretching the laminate to form a plurality of cracks in the conductive layer of the laminate, and making the repair particles The outer shell is ruptured by force, the repairing particles release the conductive liquid formed by the inner core and fill the cracks, and the conductive liquid forms a plurality of repairing conductors in the cracks. This method can reduce the increased resistance value of the conductive layer due to cracks in the stretching process, and improve the stretching ability of the conductive material.

Description

Thermoformed repair particles and method

Technical Field

The present disclosure relates to thermoformed repair particles and methods.

Background

In the manufacture of non-planar electronic products, forming a curved surface or a non-planar surface with an arbitrary shape is an important step, wherein the thermoplastic forming is suitable for the electronic products carrying wires or electronic components. However, during the stretching process of thermoforming, the conductive material on the substrate is easily damaged to cause wire breakage. In the case of various conductive materials having a limit of stretching limit, new development directions are required to increase the stretching ability and the shaping possibility of the conductive material.

Disclosure of Invention

The repairing particle comprises an inner core and an outer shell, wherein the inner core has electrical conductivity and an inner core melting point lower than the thermoplastic forming process temperature, the outer shell covering the inner core has an outer shell melting point higher than the thermoplastic forming process temperature, and the outer shell releases conductive liquid formed by the inner core after being stressed and broken. In some embodiments, the inner core comprises gallium, a gallium indium alloy, or a tin bismuth alloy. In some embodiments, the inner core comprises carbon black dissolved in an organic solvent. In some embodiments, the shell comprises a polyurea-formaldehyde resin or a metal oxide.

A laminated layer applied to thermoforming comprises a substrate, a conductive layer positioned on the substrate, a protective layer positioned on the conductive layer and a plurality of repairing particles added in the laminated layer, wherein the repairing particles comprise an inner core and an outer shell, the inner core forms a conductive liquid in thermoforming, and the outer shell is broken in thermoforming to release the conductive liquid. In some embodiments, the addition location of the repair particles includes within the conductive layer, between the conductive layer and the substrate, between the conductive layer and the protective layer, or within the protective layer. In some embodiments, the repair particles are added in an amount ranging from 10 vol% to 30 vol% based on the volume of the conductive layer and the repair particles. In some embodiments, after thermoforming, the laminate further comprises a plurality of cracks and a plurality of repair conductors, wherein the cracks are located in the conductive layer and the long side direction of the cracks is approximately perpendicular to the stretching direction of thermoforming, the repair conductors are formed by the conductive liquid located in the cracks and the repair conductors connect opposite side walls of the cracks. In some embodiments, the laminate is a touch layer of a touch panel.

A method for thermoplastic forming includes adding multiple repairing particles in laminated layer, heating laminated layer to make the kernel of repairing particles form conductive liquid, stretching flat laminated layer to form curved shape, making the conductive layer of laminated layer form multiple cracks and making the shell of repairing particles be broken by force, releasing conductive liquid formed by kernel from repairing particles and filling cracks with repairing conductor formed by conductive liquid. In some embodiments, the inner core is molten after heating, and the conductive liquid formed by the inner core forms a repair conductor after cooling. In some embodiments, the core is in a liquid state after heating, and the conductive liquid formed by the core forms a repair conductor after drying. In some embodiments, the method may be applied to in-mold forming or in-mold electronic processes.

Drawings

Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying drawing figures. It should be noted that the various features are not drawn to scale according to standard methods in the industry. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.

FIGS. 1A-1C illustrate cross-sectional views of a thermoforming apparatus at various steps in a thermoforming process, according to some embodiments.

FIG. 2 illustrates a top view of a conductive material during a stretching process, according to some embodiments.

FIG. 3 is a cross-sectional view of a stack with repair particles added to a conductive layer, according to some embodiments.

Fig. 4 depicts a cross-sectional view of a repair particle, according to some embodiments.

FIG. 5 illustrates a top view of a conductive material with repair particles added during a stretching process, according to some embodiments.

Fig. 6-8 illustrate cross-sectional views of a stack of material layers with repair particles added to the material layers outside of the conductive layer, according to some embodiments.

Reference numerals:

100 stack 104 conductive layer

110, a die 120 and a heater

200,500 cracks 300,600,700,800 laminate

302,602,702,802 substrate 304,604,704,804 conductive layer

306,606,706,806 protective layer 400 repair particles

402 inner core 404 outer shell

Repair conductor 708,808 particle layer 402

A clean and dry air H is introduced into the air inlet

R is the area W is the diameter

X, Y, Z axis

Detailed Description

To achieve the different features of the mentioned subject matter, the following disclosure provides many different embodiments or examples. Specific examples of components, materials, configurations, etc., are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. Other components, materials, configurations, etc. are also contemplated. For example, in the description that follows, forming a first feature over or on a second feature may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features are formed between the first and second features, such that the first and second features may not be in direct contact. Additionally, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.

In addition, spatially relative terms, such as "below …", "below …", "below", "above …", "above", and the like, may be used herein to describe one element or feature's relationship to another element or feature as illustrated. Spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

The present disclosure discloses a repair particle that can be applied to a molding process including thermoplastic molding, such as In-Mold forming (IMF), In-Mold Electron (IME), and the like. A substrate having conductive lines, such as a touch layer of a flexible or curved touch panel, is heated and stretched in a thermoforming process. The following description will be in terms of thermoforming examples, however it is understood that other variations involving heating and stretching are within the scope of the present disclosure.

The present disclosure discloses a repair particle having a low melting point core and adding the repair particle to a stack having a conductive layer. When the conductive layer is cracked to different degrees due to different stress of each part in the thermoplastic forming process, the repairing particles release the conductive liquid formed by the inner core at the same time. The conductive liquid forms a stable conductor in the cracks of the conductive layer, and reduces the resistance value of the conductive layer which is originally increased due to damage, so as to solve the problem of wire breakage caused by thermoplastic forming.

1A-1C are cross-sectional views of a thermoforming device in the X-Z plane, according to some embodiments. For clarity, fig. 1A-1C illustrate only a simplified thermoplastic forming apparatus. Accordingly, it is within the scope of the present disclosure that the thermoforming device may include additional components not shown in the figures. The thermoforming step includes heating, stretching, and cooling, which are respectively shown in fig. 1A to 1C. Thermoplastic forming, which includes steps other than heating, stretching, cooling, is also within the scope of the present disclosure.

FIG. 1A is a cross-sectional view of a thermoplastic forming device during a heating step, according to some embodiments. Stack 100 is on mold 110 and heater 120 is on stack 100 and covers stack 100. The stack 100 comprises a stack of substrate, conductive layers and protective layers and may include other layers of materials or electronic components therein or thereon. The mold 110 may be used in a stretching process and may include any shape of the stack 100 after it has been thermoformed. The heater 120 may heat the stack 100 to a process temperature to soften the substrate to a degree sufficient to stretch-mold the substrate into a desired shape in a subsequent process.

According to some embodiments, FIG. 1B is a cross-sectional view of a thermoplastic forming device during a stretching step, with the laminate 100 being stretch-deformed. In some embodiments, the heater 120 may have an Air inlet hole H, such that Clean Dry Air (CDA) a can pass through the Air inlet hole H and press on the stack 100 in the mold 110, as illustrated in fig. 1B. The softened laminate 100 in the mold 110 is gradually stretched and deformed by the pressurization of the clean dry air a, stretching the originally flat laminate 100 into a curve, and finally the laminate 100 conforms to the upper surface of the mold 110. In some embodiments, the heater 120 is a platen without air holes H, and the bottom of the mold 110 may have air extraction holes penetrating the mold 110, which can extract air between the laminate 100 and the mold 110, so that the laminate 100 is drawn to fit the upper surface of the mold 110 by vacuum during the drawing step. In some embodiments, heater 120 may have air inlets H, and the bottom of mold 110 may have suction holes penetrating mold 110, such that laminate 100 is simultaneously pressurized and vacuum-drawn by clean dry air A to stretch and conform to the upper surface of mold 110.

FIG. 1C is a cross-sectional view of a thermoplastic forming device during a cooling step, according to some embodiments. The laminate 100 is conformed to the upper surface of the mold 110 and gradually cooled to a non-softening temperature such that the laminate 100 has a stretched shape when released from the mold 110.

FIG. 2 is an enlarged top view of region R of FIG. 1B in the X-Y plane, according to some embodiments. For clarity, fig. 2 only shows the conductive material 104 in the stack 100, however, as mentioned above, the stack 100 may include a substrate, a passivation layer, other material layers, an electronic device, and the like. In the stretching step, the stretching deformation of the substrate has a destructive force on the conductive material, so that the conductive material 104 in the stack 100 may generate cracks 200. The cracks 200 may be irregularly shaped and mostly elongated, with the long side of the cracks 200 being oriented approximately perpendicular to the direction of tensile deformation of the stack 100. The crack 200 may occur in the conductive material 104 or at the edge of the conductive material 104. The cracks 200 may increase the resistance of the stack 100, causing a disconnection phenomenon.

In order to overcome the phenomenon that the conductive material cracks and breaks in the thermoplastic forming and stretching process, the repairing particles are added into the lamination layer comprising the conductive material, so that the conductive material is damaged in the stretching process, and meanwhile, the repairing particles can repair the cracks in the conductive material, and the resistance difference and the element driving problem caused by stretching are reduced.

Fig. 3 is a cross-sectional view of a stack 300 in the X-Z plane, according to some embodiments. The composition of the stack 300 is similar to the stack 100, including but not limited to a substrate, a conductive material, a passivation layer, other material layers, an electronic device, etc., and the stack 300 can also be used in the thermoplastic stretching process as illustrated in fig. 1A to 1C. In some embodiments, the flat laminate 300 is curved after the stretching process shown in fig. 1B, so that the laminate 300 can be used as a touch layer of a curved or flexible touch panel.

In some embodiments, stack 300 includes a substrate 302, a conductive layer 304 on substrate 302, and a protective layer 306. The material of the substrate 302 may be a plastic film (e.g., Polycarbonate (PC) film). The melting point (e.g., greater than 200 ℃) of the substrate 302 is higher than the processing temperature (e.g., 145 ℃) of the heating step in thermoforming, but at the processing temperature, the substrate 302 may soften for subsequent stretch-forming. The conductive layer 304 may be made of silver paste (silver paste), nano silver, poly ethylenedioxythiophene (pdot: PSS), and other conductive materials, and the melting point of the conductive material may be selected to be not molten at the process temperature of thermoforming, for example, when the process temperature is 145 ℃, silver paste (melting point 960 ℃), nano silver (melting point 150 ℃), and the like may be selected. The material of the protective layer 306 may be an oxide and covers the conductive layer 304 under the protective layer 306.

Unlike stack 100, stack 300 adds repair particles 400 in conductive layer 304. In some embodiments, the repair particles 400 are added to the solution of the conductive layer 304 and applied together to the conductive layer 304 of the stack 300 formed on the substrate 302, as illustrated in fig. 3.

Fig. 4 is a cross-sectional view of a conductive particle 400, according to some embodiments. Repair particle 400 is a spherical bilayer structure comprising an inner core 402 and an outer shell 404. In some embodiments, the diameter W of the repair particle 400 may be 1 micron to 5 microns, although larger or smaller diameters W may also be used.

The core 402 of the repair particle 400 is a conductive material and is also the primary component in repairing cracks in the conductive layer 304. In some embodiments, the core 402 has the property of being formed into a flowable state during the heating step of thermoforming. The melting point of the core 402 may be selected to be between the process temperature of thermoforming and room temperature such that the core 402 is in a molten state during the stretching step. The conductive liquid formed by the melted core 402 can fill up the cracks caused by stretching during the stretching and stressing process of the conductive layer 304, so as to reduce the resistance value of the conductive layer 304 raised due to the damage, thereby achieving the purpose of repairing the conductive layer 304.

In some embodiments, the core 402 in a molten state may form a solid at room temperature during the cooling step of thermoforming and become a stable conductor at the cracks connecting the conductive layers 304. In other embodiments, the melting point of the core 402 may be below room temperature, and after repairing the conductive layer 304, the conductive fluid of the core 402 may form an oxide layer on the fluid surface during the thermoforming cooling step, limiting the flow behavior of the fluid of the core 402 to form a stable conductor in the fracture of the conductive layer 304. In some embodiments, the material of the core 402 includes gallium (melting point 29.76℃), a gallium indium alloy (eutectic point 21.4℃), or a tin bismuth alloy (eutectic point 139℃.).

In some embodiments, the inner core 402 may include carbon black dissolved in an organic solvent (e.g., toluene). The core 402 including the carbon black has a flowable property during the stretching step of thermoforming, fills the cracks in the conductive layer 304, and removes the organic solvent by drying, so that the carbon black in the core 402 forms a stably connected conductive solid in the cracks.

The shell 404 of the repair particle 400 is a layer of material that keeps the repair particle 400 dispersed. In some embodiments, the core 402 may form or maintain the conductive fluid during the heating step of thermoforming, but the shell 404 may protect the core 402 and isolate the conductive fluid of the core 402 from the conductive layer 304 before the conductive layer 304 cracks due to stretching. When the conductive layer 304 cracks during the stretching step, the shell 404 is also subjected to the stretching stress and is broken, so that the conductive liquid formed by the core 402 is released and repairs the conductive layer 304. In some embodiments, to prevent premature rupture of the shell 404 before the conductive layer 304 is stretch broken to release the core 402, the shell 404 may include a heat resistance and a solvent resistance such that the shell 404 does not melt or chemically react at the processing temperature, wherein the solvent is a solvent (e.g., water, ethanol, ether, isopropyl alcohol, diethylene glycol monobutyl ether, etc.) that coats the conductive layer 304 solution. In some embodiments, the shell 404 includes an organic polymer (e.g., a polyurea-formaldehyde resin (PUF)) or a metal oxide (e.g., tin dioxide, gallium oxide).

According to some embodiments described above, the repair particles 400 are added to the conductive layer 304 such that when the stack 300 is heated to the process temperature, the core 402 of the repair particles 400 is in the form of a conductive liquid and is separated from the conductive layer 304 by the shell 404. When the conductive layer 304 is stretched and molded to generate cracks with different breaking degrees, the shell 404 of the repair particle 400 around the cracks is also broken, and the released conductive liquid of the core 402 fills up the cracks in the conductive layer 304. When the stack 300 cools, the conductive liquid of the core 402 also forms a stable conductor in the crack, connecting the crack in the conductive layer 304, and reducing the resistance that would otherwise arise from damage to the conductive layer 304. In some embodiments, the volume of the conductive layer 304 and the repair particles 400 is used as a denominator, and the repair particles 400 are added in an amount of 10 vol% to 30 vol% to provide a repair effect.

Referring to fig. 3 and 5, fig. 5 is a top enlarged view of the conductive layer 304 in the region R in the X-Y plane during the stretching step of fig. 1B of the stack 300. In the stretching step, the substrate 302 softened by the process temperature is stretched and deformed, so that the conductive layer 304 on the substrate 302 is deformed and the crack 500 is generated. At the same time, the shell 404 of the repair particle 400 around the crack 500 in the conductive layer 304 is broken by the tensile stress, releasing the conductive liquid formed by the core 402. The conductive fluid formed by the core 402 forms a repaired conductor 402' in the fracture 500 in the conductive layer 304 and cures in subsequent processes to form a stable conductor in the fracture 500. In some embodiments, repairing the conductor 402' to fill the crack 500 in the conductive layer 304 may be a complete fill. In some embodiments, the repair conductor 402 'fills the crack 500 in the conductive layer 304, and the repair conductor 402' contacts the opposite sidewalls of the crack. In some embodiments, there may be a plurality of repair conductors 402' in the fracture 500.

Fig. 6-8 are cross-sectional views of stack 600, stack 700, and stack 800 in the X-Z plane, according to some embodiments. The composition of the stack 600-800 is similar to the stack 300 containing the repair particles 400, including but not limited to substrates, conductive materials, protective layers, other material layers, electronic devices, etc., and the stack 600-800 may also be used in the thermoplastic stretching process as illustrated in fig. 1A-1C.

The stack 600 to 800 differ from the stack 300 in that the repair particles 400 are added at different locations in the stack. In some embodiments, as shown in fig. 6, the repair particles 400 may be added to a solution of the protective layer 606 and applied together to the protective layer 606 of the stack 600 on the conductive layer 604. In some embodiments, as shown in fig. 7, the repair particles 400 can be added in a solvent, which can be water or an organic solvent (e.g., ethanol, diethyl ether), and coated on the substrate 702 to form a particle layer 708 under the conductive layer 704. In some embodiments, as shown in fig. 8, the repair particles 400 can be added in a solvent, which can be water or an organic solvent (e.g., ethanol, diethyl ether), and coated on the conductive layer 804 to form the particle layer 808 on the conductive layer 804. The repair particles 400 in the stack 600 to 800 repair cracks in the conductive layer in the same manner as the stack 300, although the locations of the addition of the repair particles 400 are different.

The present disclosure discloses a repair particle for thermoforming, which comprises a core and a shell, wherein the core has conductivity and a core melting point lower than the thermoforming process temperature, and the shell releases a conductive liquid formed by the core after being broken by a force. The present disclosure also discloses a method for thermoforming, which includes adding a plurality of repairing particles in the lamination layer, wherein the repairing particles release the conductive liquid formed by the core due to the stress of the shell in the stretching process of thermoforming, the conductive liquid fills the cracks in the conductive layer and forms repairing conductors in the cracks, the resistance value of the conductive layer raised due to the cracks is reduced, and the stretching capability of the conductive material is improved.

The foregoing outlines features of some embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure.

Claims

1. A laminate for thermoforming, comprising:

a substrate;

a conductive layer on the substrate, wherein the conductive layer comprises a plurality of cracks in the conductive layer after being thermoformed;

a protective layer on the conductive layer;

a plurality of repair particles added to the laminate, wherein each repair particle comprises an inner core and an outer shell covering the inner core,

wherein the core has conductivity and a core melting point, the core melting point is lower than a process temperature of the thermoplastic forming, the core forms a conductive liquid in the thermoplastic forming,

wherein the shell has a shell melting point higher than the processing temperature of the thermoplastic forming, and the shell of the repair particles around the cracks is broken in the thermoplastic forming to release the conductive liquid, so that the conductive liquid forms a plurality of repair conductors in the cracks.

2. The laminate of claim 1, wherein the locations of the repair particles added include within the conductive layer, between the conductive layer and the substrate, between the conductive layer and the protective layer, or within the protective layer.

3. The laminate of claim 1, wherein the volume of the conductive layer and the repair particles is denominator, and the amount of the repair particles is in the range of 10 vol% to 30 vol%.

4. The laminate of claim 1, wherein the long side of the cracks is oriented approximately perpendicular to the direction of stretching of the thermoplastic, the repair conductors connecting opposite sidewalls of each of the cracks.

5. The laminate of claim 1, wherein the laminate is a touch layer of a touch panel.

6. The laminate of claim 1, wherein the core comprises gallium, a gallium-indium alloy, or a tin-bismuth alloy.

7. The laminate of claim 1, wherein the core comprises carbon black dissolved in an organic solvent.

8. The laminate of claim 1, wherein the skin comprises a polyurea-formaldehyde resin or a metal oxide.

9. A method of thermoforming, comprising:

adding a plurality of repair particles in a laminate, wherein each repair particle comprises an inner core and an outer shell covering the inner core, the inner core has an inner core melting point lower than a process temperature of the thermoforming, and the outer shell has an outer shell melting point higher than the process temperature of the thermoforming;

heating the laminated layer to enable the inner core of each repair particle to form a conductive liquid;

stretching the laminated layer to make the flat laminated layer stretched into a curved shape, wherein a conductive layer of the laminated layer forms a plurality of cracks, and the shells of the repairing particles around the cracks are stressed to break;

each repairing particle releases the conductive liquid formed by the inner core, and the conductive liquid is filled into the cracks; and

the conductive liquid forms a plurality of repair conductors in the cracks.

10. The method of claim 9, wherein the core is molten after heating, and the conductive liquid formed by the core forms the repair conductors after cooling.

11. The method of claim 9, wherein the core is in a liquid state after heating, and the conductive liquid formed by the core forms the repair conductors after drying.

12. The method of claim 9, wherein the method is applied to in-mold forming or in-mold electronics.