KR102050295B1 - Method for manufacturing smart lends including 3-dimensionally patterned interconnects and the smart lends manufatured by the method - Google Patents

Abstract

The present invention relates to a method for manufacturing a smart lens, which comprises the steps of: arranging one or more chips on a substrate; spraying a conductive ink onto the substrate through a mask and forming a three-dimensional interconnect pattern to be connected to the chip; and transferring the patterning substrate on which the interconnect pattern is formed onto a contact lens, wherein the substrate is flexible and the mask is etched to correspond to at least a partial cross section of the patterning substrate, and to a smart lens manufactured by the method.

Description

TECHNICAL FIELD OF THE INVENTION A method for manufacturing a smart lens including a three-dimensional interconnect pattern, and a smart lens manufactured by the method.

The present invention relates to an element technology required for manufacturing a smart lens, and more particularly, to a method for manufacturing a smart lens by forming an interconnect pattern for connecting elements on a flexible substrate corresponding to the deformation of the lens in three dimensions. It relates to a smart lens manufactured by the method.

In order to analyze the health of the patient, it was common to collect the patient's body tissue, blood, and the like. However, the patient's pain is essential in this collection process, and long-term patients with a long collection period and a long period of time, in particular, diabetic patients whose treatment lasts a lifetime, have had inconveniences of living in long-term pain. Thus, there has always been a need for non-invasive medical devices that enable very efficient and painless diagnosis in diabetics.

In recent years, in response to such demands, various health monitoring tools based on contact lenses, which do not require blood collection and the like, called smart contact lenses, have been attempted. This contact lens requires some components, such as biosensors, thin film batteries, and sensor-related chips (eg, sensor managing chips, etc.) to be configured on a lens that provides high flexibility as a substrate for monitoring.

Here, interconnects that electrically connect the components disposed on the lens are one of the important components for implementing a functional smart contact lens. Such interconnects can be implemented by various methods. For example, the conductive thin film may be manufactured by vacuum deposition, or more easily, by printing to form a conductive pattern having an interconnect function by printing.

The interconnect pattern must satisfy several conditions. For example, the pattern needs to cover both the substrate surface and the electrodes formed on the top surface of each unit element. The mechanical and electrical continuity of the pattern must be ensured by overcoming the height of the individual elements placed on the contact lens. In addition, due to the specificity of the contact substrate, the pattern must be flexible and resistant to repetitive stresses.

1 is a diagram for explaining a conductive interconnect pattern, which may be attempted by vacuum equipment, according to one conventional embodiment.

One conventional embodiment has to form a three-dimensional pattern directly by the deposition of a conductive material in a vacuum equipment, but the step caused by the different height of the device located on the substrate surface by the conventional process optimized for the formation of the two-dimensional pattern There is a limit to forming a three-dimensional pattern by connecting. As a result, when using conventional vacuum equipment, referring to FIG. 1, it has poor cover performance of conductive coatings (ie, across the sides of the device) across substrate damage and step height in vacuum.

On the other hand, a printing process using a conductive ink may be performed even at room temperature. However, when using a general conductive ink, there is also a limit in connecting the pattern on the substrate with the top surface of the element by overcoming the step given by each element on the substrate.

In addition, the foregoing conventional embodiments have limitations in forming successful 3D patterns on flexible substrates that tend to degrade at high temperatures in metal deposition and lithography based vacuum processes at high temperatures.

Patent Publication No. 10-2017-0077369

According to an aspect of the invention, to provide a method for manufacturing a smart lens including a three-dimensional interconnect pattern.

In addition, to provide a smart lens manufactured by the above method.

A method of manufacturing a smart lens according to an aspect of the present invention comprises the steps of placing one or more chips on the substrate; Spraying conductive ink through the mask onto the substrate to form an interconnect pattern to connect to the chip; And transferring the patterning substrate on which the interconnect pattern is formed on a contact lens. Here, the substrate is flexible and the mask is etched to correspond to at least some cross section of the patterning substrate.

In one embodiment, the chip has a height higher than the surface of the adjacent substrate. In addition, the chip may have a height of 1um to 1,000um.

In one embodiment, the conductive ink may be made of Ag, Ag Nano-Wire (AgNW), Multi-walled carbon nanotubes (MWCNT), or a combination thereof. In addition, the conductive ink may be Ag-AgNW composite ink, characterized in that the AgNW is 0.3wt%.

In one embodiment, the interconnect pattern may be formed at 18 ℃ to 25 ℃.

In one embodiment, the substrate may be designed to be C-type.

In one embodiment, the substrate may be made of a material selected from the group consisting of polymide (PI), poly (dimethylsiloxane) (PDMS), parylene, and combinations thereof.

In one embodiment, the patterning substrate may have a rate of change of sheet resistance (Rs) before and after deformation within a range of 15.2% within a deformation range corresponding to a bending radius of 3 mm.

In one embodiment, the method may further comprise covering the patterned substrate portion transferred onto the contact lens with an additional lens.

In one embodiment, the patterned substrate transferred onto the contact lens may be adaptable to omnidirectional bending stress exerted by the shape of the contact lens.

A smart lens including a patterning substrate transferred onto a contact lens according to another aspect of the present invention, wherein the patterning substrate connects at least one of a chip and an electrode disposed on the patterning substrate, and at least one of the chip and the electrode. It may include at least one of the interconnect pattern. Here, the interconnect pattern is formed by spraying conductive ink onto the substrate through a mask, and the mask is etched to correspond to at least a partial cross section of the patterning substrate on which the interconnect pattern is formed.

Smart lens manufacturing method according to an aspect of the present invention can implement the interconnect in the form of a pattern for connecting the components on the substrate forming the omni-directional curved surface by spray printing a conductive ink. Here, the pattern may not only connect the components of the smart lens in two dimensions, but also function as a three-dimensional interconnect connecting components having different heights. For example, it is possible to form conductive patterns of various three-dimensional structures, such as a structure connecting to the top surface electrode of a device having a thickness of 300 μm (for example, a microchip, etc.), or a concave shape having a high surface-to-volume ratio. . And it may have a sheet resistance (RS) of 0.396Ω / □ over a step of 300um.

In particular, the pattern of the smart lens ensures the interconnect performance between components even if the repetitive stress due to the contact lens function acts on the substrate. For example, it may be deformed to adapt to bending stress corresponding to a bending radius of 3 mm. In addition, even when the bending stress is applied, it has a value of Rs that varies within the observed range of about 15%.

In addition, the manufacturing method can control the concentration of the ink according to the surface-to-volume ratio to form a three-dimensional pattern in a single fabrication process (single fabrication process). In particular, it is possible to form three-dimensional patterns at very low temperatures (eg, room temperature) compared to conventional conductive pattern fabrication processes such as metal evaporation or lithography based vacuum processes. Thus, the manufacturing method does not cause thermal damage on the substrate.

The effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

BRIEF DESCRIPTION OF DRAWINGS To describe the technical solutions in the embodiments of the present invention or in the prior art more clearly, the drawings required in the description of the embodiments are briefly introduced below. It is to be understood that the drawings below are for the purpose of describing the embodiments herein and are not intended to be limiting. In addition, some elements to which various modifications, such as exaggeration and omission, may be shown in the following drawings for clarity of explanation.
1 is a diagram for explaining a conductive interconnect pattern, which may be attempted by vacuum equipment, according to one conventional embodiment.
2 is a conceptual flowchart of a method of manufacturing a smart lens according to an embodiment of the present invention.
3 is an image diagram illustrating an experimental smart lens manufactured by the manufacturing method of FIG. 2 according to an embodiment of the present invention.
4 is an image diagram of the microstructure of the interconnect pattern according to the components of the conductive ink, taken by SEM, according to one embodiment of the invention.
FIG. 5 is a diagram illustrating resistance related performance of an interconnect pattern of a smart lens according to an embodiment of the present invention, and FIG. 6 is a diagram of an interconnect pattern of a smart lens according to an embodiment of the present invention. It is a figure for demonstrating bending performance.
FIG. 7 is an image diagram of a microstructure of component-specific interconnect patterns of conductive inks for bending of the patterning substrate 250 according to one embodiment of the present invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular forms used in the present invention and the appended claims are intended to include the plural forms as well, unless the context clearly indicates otherwise. It is also to be understood that the term "and / or" as used herein includes any or all possible combinations of one or a plurality of related enumerated items.

When a portion is referred to as being "above" another portion, it may be just above the other portion or may be accompanied by another portion in between. In contrast, when a part is mentioned as "directly above" another part, no other part is involved between them.

Terms such as first, second, and third are used to describe various parts, components, regions, layers, and / or sections, but are not limited to these. These terms are only used to distinguish one part, component, region, layer or section from another part, component, region, layer or section. Accordingly, the first portion, component, region, layer or section described below may be referred to as the second portion, component, region, layer or section without departing from the scope of the invention.

The terminology used herein is for reference only to specific embodiments and is not intended to limit the invention. As used herein, the singular forms “a,” “an,” and “the” include plural forms as well, unless the phrases clearly indicate the opposite. As used herein, the meaning of "comprising" embodies a particular characteristic, region, integer, step, operation, element and / or component, and the presence of other characteristics, region, integer, step, operation, element and / or component It does not exclude the addition.

Unless defined otherwise, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. Commonly defined terms used are additionally interpreted to have a meaning consistent with the related technical literature and the presently disclosed contents, and are not interpreted in an ideal or very formal sense unless defined.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a flowchart for conceptually explaining a method for manufacturing a smart lens (hereinafter, referred to as a "manufacturing method") according to an embodiment of the present invention, and FIG. 3 is a diagram according to an embodiment of the present invention. It is an image diagram of the smart lens manufactured by the manufacturing method of 2.

Referring to FIG. 2, the manufacturing method includes disposing a chip 210 on a substrate 10 (S210) and using conductive ink to form an interconnect pattern 230 connected to the chip 210. Spraying onto the substrate 210 through a mask 220 (S230); And transferring the patterning substrate 250 on which the interconnect pattern 230 is formed on the contact lens 270 through step S230. When the manufacturing method of FIG. 2 is performed, a smart lens including a deformable patterning substrate 250 may be manufactured as a circuit including the chip 210 and the interconnect pattern 230 as illustrated in FIG. 3.

In step S210, the substrate 10 is made of a flexible material to correspond to the deformation function of the contact lens. The substrate 10 may be designed or modified to have a curved shape (eg, C-type), or the substrate 10 may correspond to the curved shape of the contact lens when the substrate 10 is mounted on the contact lens. The substrate 10 may be made of a material selected from the group consisting of polymide (PI), poly (dimethylsiloxane), PDylene, parylene, and combinations thereof. In some embodiments, the substrate 10 may be made of a flexible polymer having a light transmissive material for use as a smart lens.

In one embodiment, the substrate 10 may be made of PI having physical stability, thermoelectric insulation and chemical resistance. When the substrate 10 is made of PI, the substrate 10 has at least one characteristic value (Rs, dimensional stability, thermal conductivity, etc.) relatively superior to other flexible polymers (eg, PDMS (poly (dimethylsiloxane), or Parylene, etc.). Further, in some embodiments, when a cooling process is applied for pattern formation immediately after spraying the conductive ink in step S250, the substrate made of PI may be formed by a pattern of thermal expansion coefficient difference between the substrate and the pattern during the cooling process. Cracks do not occur relatively.

The substrate 10 has a size and thickness suitable for being manufactured with a smart lens.

In step S210, the chip 210 may be configured to perform a function associated with the use of the substrate 10. In one embodiment, where the use of the substrate 10 is for use in a non-invasive medical device, the chip 210 may have functions associated with the sensor, such as sensor control, sensor managing. Chips and the like. One or more chips 210 may be disposed on the substrate 10 according to the design of a circuit.

The chip 210 has a height so as to generate a step height compared to the surface of the substrate 10. In one embodiment, the height may be 1um to 1,000um. For example, the chip 210 may have a height of 60um. In some embodiments, the height can be 250um to 300um.

Referring back to FIG. 2, conductive ink is sprayed onto the substrate 10 to form the interconnect pattern 230 (S230). The conductive ink is sprayed through the mask 220 positioned between the substrate 10 and the sprayer, so that the patterning substrate 250 including the interconnect pattern 230 is manufactured (S250). The interconnect pattern 250 may be connected to the chip 210, as shown in FIGS. 2B and 3, or may be connected between the chip 210 and the electrode 240, or between different chips 210. You can also connect. The path of the interconnect pattern 250 is determined by the shape etched into the mask 220. The interconnect pattern 250 may be formed as shown in FIG. 2, or may be formed according to a patterned pattern design designed for the purpose of utilizing a smart lens.

The mask 220 is etched to correspond to a portion of the predesigned patterning substrate 250, or at least some and / or all of the paths of the interconnect pattern 230. The cross section of the mask 220 corresponds to the cross section of the circuit that allows the contact lens to function as a smart lens. For example, the mask 220 shown in FIG. 2 may be used to form the interconnect pattern 230 shown in FIG. 2B.

In addition, the electrode 240 of the patterning substrate 250 may be formed by a printing process in which spraying is performed, such as the interconnect pattern 230. In this case, as shown in FIG. 2, the mask 220 used to form the electrode 240 may be etched to form the electrode 240 of the circuit on the substrate 10. In another embodiment, the electrode 240 may be formed on another substrate and transferred to be connected to another end that is not connected to the chip 210 in the interconnect pattern 230 of the patterning substrate 250.

The conductive ink is sprayed onto the substrate 10 by an electrospray method. The interconnect pattern 230 formed by the elctrosprary method is finely and uniformly formed on the substrate 10. In one embodiment, conductive ink may be sprayed such that interconnect pattern 230 comprises one or more sublayers.

The conductive ink consists of Ag, Ag Nano-Wire (AgNW), Multi-walled carbon nanotubes (MWCNT), and combinations thereof. The conductive ink may include AgNW, or MWCNT to serve as a frame for supporting the sublayers of the interconnect pattern 230 to be printed. AgNW, or MWCNT, provides durability to the patterning substrate 250 against the occurrence of cracks and propagation of the cracks based on the deformation of the patterning substrate 250.

4 is an image diagram of the microstructure of the interconnect pattern according to the components of the conductive ink, taken by SEM, according to one embodiment of the invention.

In one embodiment, the conductive ink used in step S250 may be an Ag-AgNW composite ink, characterized in that the AgNW is 0.3wt%.

4 a to 4c show the microstructure of the pattern with different conductive structures depending on the AgNW content.

If the conductive ink contains AgNW, a low defect density anisotropic material that functions as a path for electrons to move easily (ie, Ag-AgNW composite ink), the interconnect of the patterned substrate 250 Pattern 230 has a relatively high conductivity. As shown in FIGS. 4B and 4C, when the conductive ink contains AgNW, interconnect pattern 230 includes a highway-like structure that passes through the Ag's small crystal contact point. However, when the conductive ink is made of pure Ag, the interconnect pattern 230 formed on the patterning substrate 250 has no highway structure, as shown in FIG. 4A. Thus, it has a relatively high resistance (i.e. low conductivity) due to electron scattering at the junctions of the granules of Ag.

4D-4F show the microstructure of interconnect patterns 230 having different internal structures by AgNW content. When the AgNW content included in the conductive ink is greater than or equal to a predetermined reference (eg, 0.3 wt% or more), the interconnect pattern 230 may be formed to have a thickness of 300 μm as shown in FIG. 4F. This is because unlike the pure Ag conductive ink of FIG. 4D, it does not include multiple Ag rings with tens of um diameters produced by the coffee ring effect. In addition, unlike the conductive ink containing AgNW of less than the predetermined standard of Figure 4e, the content of AgNW is relatively high, so even if the thickness of the sublayers of the interconnect pattern 230 is greater than or equal to 270 um, the interconnect patterns originally printed on the connection portions of the sublayers ( This is because the internal structure of 230 is maintained.

As such, in step S230, the concentration of the ink may be controlled according to the surface-to-volume ratio to form a three-dimensional pattern in a single fabrication process.

In operation S230, the three-dimensional interconnect pattern 230 may be formed at room temperature. For example, it may be formed at 18 ℃ to 25 ℃.

Additionally, the step of heating the conductive ink electrosprayed onto the substrate after the electrospray for a predetermined time may be further performed. For example, a process of applying a voltage of 9 kV to the droplets of the conductive ink and heating to 120 ° C. for 30 minutes may be further performed. In addition, a process of cooling the conductive ink after the injection may be further performed.

As a result of the spraying of the conductive ink through the mask 220, the patterning substrate 250 may be manufactured by forming the interconnect pattern 230 in three dimensions on the flexible substrate 10 (S250). Therefore, even if an element such as a chip disposed on the substrate 10 or an electrode has a height within a predetermined range, the element and the element and the element and the electrode can be connected by using the three-dimensional interconnect pattern 230, and furthermore, Patterning substrate 250 may be used to manufacture smart lenses.

In one embodiment, the patterning substrate 250 fabricated by the above-described steps S210 and S250 is transferred onto the contact lens 270 (S270). The transferred patterned substrate 250 may be deformed while adapting to the forward bending stress given by the shape of the contact lens 270 as shown in FIG. 2B.

In one embodiment, the step of covering the portion of the patterned substrate 250 transferred on the contact lens 270 with an additional lens to protect the patterning substrate 250 from foreign materials, impact, and the like. The additional lens is not necessarily limited to the lens, and may be replaced with various films, films, and the like, which may cover the portion of the patterning substrate 250.

FIG. 5 is a diagram illustrating resistance related performance of an interconnect pattern of a smart lens according to an embodiment of the present invention, and FIG. 6 is a diagram of an interconnect pattern of a smart lens according to an embodiment of the present invention. It is a figure for demonstrating bending performance.

5 and 6 are experimental results measured by the following experimental conditions.

First condition (characteristic analysis of the pattern): Rs of the patterning substrate 250 was measured by a 4-point probe method using a probe station (MSTECH Co., Ltd., Korea). Rs was applied with a correction factor of 0.9988 corresponding to the geometric characteristics of the pattern of the measured resistance. After analyzing Rs of the patterning substrate 250, a bending test was performed using an x-axis actuator (NAMIL OPTICAL INSTRUMENTS Co., South Korea). The microstructure of the pattern was photographed using a field emission scanning electron microscope (FE-SEM) (Inspect F, Japan).

2nd condition (formation of the interconnect pattern 230): As a board | substrate 10, a C type PI film (thickness: 12.5um) is prepared. In addition, a three-dimensional height defining PI flake was placed as an example alternative to a real electronic chip. Mask 220 is a metal shadow mask (SCTECH, South Korea) was placed on the PI substrate 10 and the electrospray process was performed.

The dynamic properties of the smart lens, including the patterning substrate 250, depend on the components of the conductive ink.

The resistance characteristic (change ratio of Rs) according to the bending radius of the patterning substrate 250 is calculated by the following equation.

[Equation 1]

Rate of change of Rs = (Rsc-Rso) / Rso

Here, Rso is Rs of the patterning substrate 250 before deformation, and Rsc represents Rs of the patterning substrate 250 after deformation. The patterning substrate 250 is subjected to tensile stress as the bending progresses, such as in the x-axis direction. While the radius of curvature varies from 14 mm to 3 mm, Rs is inversely proportional to the radius. As shown in FIG. 5, the patterning substrate 250 has a stable Rs within a critical radius of curvature. In particular, the patterning substrate 250 using the Ag-AgNW composite ink including 0.3 wt% AgNW has an Rs change of about 15% compared to the initial Rs.

In one embodiment, the Rs of the patterning substrate 250 remains nearly constant even after repeated bending of 3 mm radius of curvature. In particular, the patterning substrate 250 using the Ag-AgNW composite ink including 0.3 wt% AgNW may maintain the Rs characteristic even after 1000 bendings are repeated as shown in FIG. 6.

FIG. 7 is an image diagram of a microstructure of component-specific interconnect patterns of conductive inks for bending of the patterning substrate 250 according to one embodiment of the present invention.

If bending is repeated, cracks may occur in the interconnect pattern 230. However, the interconnect pattern 230 containing AgNW has a structure such that a bridge is formed over the crack as shown in FIG. 7. Therefore, even if a crack occurs by AgNW, conductivity is maintained.

The foregoing experimental conditions are merely exemplary, and it will be apparent to those skilled in the art that the manufacturing conditions of the smart lens of the present invention are not limited thereto.

Although the present invention described above has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and variations may be made therefrom. However, such modifications should be considered to be within the technical protection scope of the present invention. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

The circuit for a smart lens according to an aspect of the present invention is manufactured by a printing process for forming a three-dimensional interconnect pattern. Three-dimensional interconnect patterns can be manufactured in high quality by a simple manufacturing process at room temperature, making it very easy to manufacture custom circuits.

Such a smart lens circuit is particularly helpful in the development and commercialization of future flexible electronic products because of the omnidirectional flexibility. In addition, by printing the pattern directly three-dimensionally by spraying the conductive ink, a process such as additionally using a conductive adhesive to fix the interconnect to the circuit element is unnecessary. Furthermore, using such a printing process can be usefully used for the development of biomedical medical devices and smart wearable devices with very high process efficiency.

Claims (12)

As a method of manufacturing a smart lens,
Placing one or more chips (chips) on the substrate, the chip also has a height greater than the adjacent surface of the substrate, an electrode located on a surface opposite to the substrate;
Forming an interconnect pattern on the substrate to connect the electrodes of the chip, wherein the interconnect pattern is formed by spraying a conductive ink whose concentration is controlled according to a surface-to-volume ratio through a mask ; And
Transferring the patterning substrate on which the interconnect pattern is formed onto a contact lens;
The substrate is flexible, and the mask is etched to correspond to at least some cross-section of the patterning substrate. delete The method of claim 1,
The height is characterized in that 1um to 1,000um. The method of claim 1,
The conductive ink is Ag, AgNW (Ag Nano-Wire), MWCNT (Multi-walled carbon nanotubes) characterized in that made of a material consisting of a combination thereof. The method of claim 4, wherein
The conductive ink is an Ag-AgNW composite ink, characterized in that AgNW is 0.3wt%. The method of claim 1,
The interconnect pattern is formed at 18 ° C to 25 ° C. The method of claim 1,
And said substrate is designed to be C-type. The method of claim 1,
Wherein the substrate is made of a material selected from the group consisting of poly (mide), poly (dimethylsiloxane), PDMS, parylene, and combinations thereof. The method of claim 1,
And wherein said patterning substrate has a rate of change of sheet resistance (Rs) before and after deformation within a range of 15.2% within a deformation range corresponding to a bending radius in the range of 3 mm. The method of claim 1,
Covering the patterned substrate portion transferred onto the contact lens with an additional lens. The method of claim 10,
And the patterned substrate transferred onto the contact lens is adaptable to omnidirectional bending stress applied by the shape of the contact lens. A smart lens comprising a patterning substrate transferred onto a contact lens, wherein the patterning substrate comprises at least one chip and a first electrode disposed on the patterning substrate and an interconnect connecting at least one of the chip and the first electrode. Include at least one of the patterns,
The chip disposed on the substrate includes a surface having a height higher than that of an adjacent substrate and a second electrode located on the surface of the substrate,
The interconnect pattern is formed on the substrate so as to be connected to the second electrode of the chip, and a conductive ink controlled according to a surface-to-volume ratio is sprayed onto the substrate through a mask, and the mask is formed by the interconnect pattern. A smart lens etched to correspond to at least a partial cross section of the formed patterning substrate.

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