CN113433062B - Method and device for testing joint force between stamp unit and sample - Google Patents
Method and device for testing joint force between stamp unit and sample Download PDFInfo
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- 238000000034 method Methods 0.000 title claims abstract description 63
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- 239000011347 resin Substances 0.000 claims description 4
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Abstract
The application provides a method and a device for testing the joint force between a stamp unit and a sample. The test method comprises the following steps: manufacturing a flexible film, wherein the design parameters of the flexible film of the stamp unit are obtained by the design method of the stamp unit, and the flexible film with the joint post is manufactured; assembling a flexible membrane and a sample, wherein the flexible membrane is assembled to an upper fixture having an air cavity, and the sample is mounted to a lower fixture and opposite to the bond post; and testing and verifying, wherein the joint column is jointed with the sample, the actual joint force between the stamp unit and the sample is measured by changing the air pressure in the air cavity of the upper clamp and the distance between the upper clamp and the lower clamp, and the actual joint force is compared and verified with the theoretical joint force obtained by the design method. In this way, the above-described test method and test apparatus can verify the joining force obtained in the design method of the stamp unit, thereby ensuring the reliability of the design method, and have general applicability.
Description
Technical Field
The application relates to the field of testing of a stamp unit in flexible electronic technology, in particular to a method and a device for testing the joint force between the stamp unit and a sample.
Background
The flexible electronic technology is widely applied to various fields such as the biomedical monitoring field and the like due to the superior mechanical properties and material characteristics, and the device realized by the flexible electronic technology can be in contact with the human body for a long time without influencing the normal physiological activity of the human body due to the superior mechanical properties and material characteristics. Moreover, the demand for wearable medical devices manufactured using flexible electronics is also increasing today.
In order to make the device realized by using flexible electronic technology implement industrial production better, the skilled person proposes a manufacturing method for transferring the circuit to the flexible substrate based on the traditional hard circuit processing technology. The most important process in this method is the transfer process, and the success of the transfer process directly determines whether the device can be made flexible. The existing methods for transferring, for example, using shape memory polymers, microstructures, curvatures, etc., have certain limitations, so that the use of these methods is correspondingly limited.
For the transfer process, the key is to adjust the interface bonding strength between the stamp and the sample. When the sample is peeled from the donor substrate, the seal and the sample have higher interface bonding strength; when the sample is printed on the receptor substrate, the interface bonding strength between the stamp and the sample needs to be kept small, so that the sample can be picked up from the donor substrate and printed on the receptor substrate during the transfer process. The adjustment and control of parameters such as interface bonding strength are difficult, and a stamp capable of obtaining expected interface bonding strength with a sample is needed to be tested.
Disclosure of Invention
The present application has been designed and completed to solve the above-mentioned drawbacks of the prior art. An object of the present application is to provide a method and apparatus for testing a bonding force between a stamp unit and a sample, which can verify the bonding force obtained in a method of designing the stamp unit, thereby ensuring reliability of the design method.
In order to achieve the purpose of the application, the following technical scheme is adopted in the application.
The application provides a method for testing the joint force between a stamp unit and a sample, which is characterized by comprising the following steps:
manufacturing a flexible film, wherein the design parameters of the flexible film of the stamp unit are obtained by the design method of the stamp unit, and the flexible film with the joint post is manufactured by utilizing the design parameters;
assembling a flexible membrane and a sample, wherein the flexible membrane is assembled to an upper fixture having an air cavity such that the flexible membrane encloses the air cavity and the engagement posts face a lower fixture, the sample is mounted to the lower fixture and opposite the engagement posts; and
and testing and verifying, wherein the joint column is jointed with the sample, the actual joint force between the stamp unit and the sample is measured by changing the air pressure in the air cavity of the upper clamp and the distance between the upper clamp and the lower clamp, and the actual joint force is compared with the theoretical joint force obtained by the design method for verification.
In an alternative, in the step of manufacturing a flexible film, a mold is manufactured using the design parameters, a film material is cast in the mold, and the film material is removed from the mold after being cured, thereby obtaining the flexible film, which includes a sheet-shaped flexible layer and a plurality of the bonding posts on one side surface of the flexible layer.
In another alternative, the mold is made using 3D printing of a light curable resin material.
In another alternative, the membrane material is polydimethylsiloxane.
In another alternative, in the step of test verification, the kind of sample on the lower jig is changed, and the actual bonding force between the bonding column and the different kind of the sample is measured.
In another alternative, in the designing method, the height of the joint columns in the initial state of the stamp unit is h, the interval between the adjacent joint columns is g, the diameter of the joint columns is d, the width of the rigid base body of the stamp unit in the longitudinal section is 2b, the separation length of the stamp unit and the sample in the longitudinal section is l,
let pmIs the air pressure in the air cavity of the rigid substrate,
is the elastic modulus, I, of the flexible filmzIs the moment of inertia of the flexible membrane, and k4＝d/[Izh(d+g)]，
The theoretical bonding force between the stamp unit and the sample is the following formula 1:
in another alternative, the critical displacement during separation between the stamp unit and the sample is formula 2 below:
wherein γ represents the interface strength between the stamp unit P and the sample S, the maximum theoretical bonding force between the stamp unit and the sample is obtained based on the following formula 1 and formula 2 as formula 3:
the present application also provides a testing device adopting the method for testing the bonding force between the stamping unit and the sample according to any one of the above technical solutions, wherein the testing device comprises the upper clamp, the lower clamp and a stretcher, and the stretcher can relatively displace the upper clamp and the lower clamp in the directions approaching to and departing from each other.
In an alternative, the upper jig includes a first clamped portion and an upper jig main body, the first clamped portion is fixed to the upper jig main body, the first clamped portion is located above the upper jig main body, the first clamped portion is used for being mounted to the stretching machine, the upper jig main body is formed with an air cavity which is open towards the lower side, and the periphery of the opening of the upper jig main body is formed with a glue guide groove for containing an adhesive, so that the flexible film can be fixed to the upper jig.
In another alternative, the lower jig includes a second clamped portion fixed to the lower jig main body, the second clamped portion being located below the lower jig main body, the second clamped portion being for mounting to the drawing machine, and the lower jig main body having a socket for inserting the sample.
By adopting the technical scheme, the application provides a method and a device for testing the bonding force between the stamp unit and the sample. The test method comprises the following steps: manufacturing a flexible film, wherein the design parameters of the flexible film of the stamp unit are obtained by the design method of the stamp unit, and the flexible film with the joint columns is manufactured by using the design parameters; assembling a flexible membrane and a sample, wherein the flexible membrane is assembled to an upper fixture having an air cavity such that the flexible membrane encloses the air cavity and the engagement post faces the lower fixture, and the sample is mounted to the lower fixture and opposite the engagement post; and testing and verifying, wherein the joint column is jointed with the sample, the actual joint force between the stamp unit and the sample is measured by changing the air pressure in the air cavity of the upper clamp and the distance between the upper clamp and the lower clamp, and the actual joint force is compared and verified with the theoretical joint force obtained by the design method. In this way, the above-described test method and test apparatus can verify the joining force obtained in the design method of the stamp unit, thereby ensuring the reliability of the design method. Moreover, the test method and the test device can be suitable for testing the joint force between different samples and the seal unit, and have universal applicability.
Drawings
Fig. 1 is a schematic structural diagram illustrating a stamp and a stamp unit constituting the stamp according to an embodiment of the present application.
Fig. 2 is a schematic sectional view showing the stamp unit in fig. 1, in which a longitudinal section of the stamp unit is shown.
Fig. 3 is a schematic diagram illustrating steps of a transfer process implemented using the stamp unit in fig. 2.
Fig. 4 is a schematic diagram showing the step shown in (F) of fig. 3, in which design parameters of the stamp unit are shown.
Fig. 5 is a schematic diagram showing a simplified mechanical model of a flexible membrane of the stamp unit at the step shown in (F) of fig. 3.
Fig. 6 is a force analysis diagram showing a joint section in the mechanical model in fig. 5.
Fig. 7 is a force analysis diagram showing a separation section in the mechanical model in fig. 5.
FIG. 8 is a graph showing the relationship between total energy of the system and separation length under different displacement conditions.
FIG. 9 is a graph showing the relationship between total energy of the system and separation length at different interface intensities.
Fig. 10 is a graph showing the relationship between total system energy and separation length under certain interface strength and displacement, but different gas pressures.
Fig. 11 is a graph showing the relationship between displacement and separation length under the condition of a certain air pressure but different interface strengths.
Fig. 12 is a graph showing the relationship between displacement and separation length under the condition of a certain interface strength but different air pressures.
Fig. 13 is a graph showing the relationship between the force and the displacement under the condition that the air pressure is constant but the interface strength is different.
Fig. 14 is a graph showing the relationship between the maximum bonding force and the characteristic dimension under the condition that the air pressure is constant but the interface strength is different.
Fig. 15 is a schematic view showing a mold for manufacturing a flexible film of a stamp unit.
FIG. 16 is a schematic diagram showing another mold for making the flexible membrane of the stamp unit.
Fig. 17 is a schematic view showing a measuring apparatus for measuring the bonding force between a flexible film and a sample.
Fig. 18 is a schematic diagram showing the structure of an upper jig of the measuring apparatus in fig. 17.
Fig. 19 is a schematic view showing the structure of a lower jig of the measuring apparatus in fig. 17.
Description of the reference numerals
ST stamp P stamp Unit 1 rigid substrate 11 air chamber 12 air channel 2 flexible film 21 flexible layer 22 bonding post S sample D Donor substrate A receiver substrate
Concave 32 hole of M die 31
41 the upper clamp 411, the first clamped part 412, the upper clamp main body 413, the glue guide groove 42, the lower clamp 421 and the lower clamp main body 43 stretcher of the second clamped part 422.
Detailed Description
Exemplary embodiments of the present application are described below with reference to the accompanying drawings. It should be understood that the detailed description is only intended to teach one skilled in the art how to practice the present application, and is not intended to be exhaustive or to limit the scope of the application.
Hereinafter, a structure of a stamp and a stamp unit constituting the stamp according to an embodiment of the present application will be described first with reference to the accompanying drawings.
(Structure of stamp and stamp Unit according to an embodiment of the present application)
The stamp ST according to an embodiment of the present application is used to move the sample S from the donor substrate D to the receptor substrate a during transfer, and can be smoothly separated from the sample S in a state where the sample S is bonded to the receptor substrate a. As shown in fig. 1, the stamp ST includes a plurality of stamp units P arranged in a matrix array. The plurality of stamp units P are relatively independent, and particularly, each stamp unit P can be independently controlled, for example, but not limited to, independent control of the stamp unit P in the transfer process is realized by respectively designing and regulating each independent stamp unit P.
As shown in fig. 1 and 2, each stamp unit P includes a rigid base 1 and a flexible film 2 assembled together. Specifically, the rigid base 1 is formed inside with an air chamber 11 and an air passage 12 which communicate with each other, the air chamber 11 has a rectangular parallelepiped shape and has a square opening which opens downward, and the air passage 12 is located above the air chamber 11 and communicates with the air chamber 11. The flexible membrane 2 includes a flexible layer 21 and a plurality of bond posts 22. The flexible layer 21 has a sheet-like structure, and an outer edge portion of the flexible layer 21 is fixed to the rigid base 1, for example, by bonding and closes the opening of the air chamber 11. A plurality of bond posts 22 (25 bond posts 22 in this embodiment) are secured to the surface of the flexible layer 21 facing away from the air cavity 11.
It will be appreciated that the "rigidity" of the rigid substrate 1 is relative to the "flexibility" of the flexible membrane 2. The rigid substrate 1 and the flexible membrane 2 may be made of different materials or of the same material, for example, the wall thickness of the flexible layer 21 of the flexible membrane 2 may be smaller than the wall thickness of the rigid substrate 1.
In the initial state of the stamp unit P in non-operation, the plurality of bonding posts 22 are parallel to each other, and the bonding posts 22 are arranged in a 5 × 5 matrix array, with the center of the matrix array coinciding with the center of the square opening. As shown in fig. 3, during the transfer process, bonding posts 22 are used to bond sample S to transfer sample S from donor substrate D to receptor substrate a and to bond sample S to receptor substrate a. In the separation step shown in fig. 3 (F), the bonding columns 22 can be separated from the sample S bonded to the receptor substrate a by changing the air pressure in the air chambers 11 so that the flexible layer 21 of the flexible film 2 is deformed. For a stamp ST including a plurality of stamp units P, the air pressures of the air chambers 11 of these stamp units P are preferably independently adjustable.
(transfer process using stamp Unit according to an embodiment of the present application)
The transfer process will be described below with a stamp unit P as a representative. Fig. 3 shows a state of the stamp unit P in each step in the entire transfer process. In this transfer process, first, as shown in fig. 3 (a) and (B), a downward displacement is applied to the entire stamp unit P, so that a strong bonding force is formed between the stamp unit P and the sample S; then, as shown in fig. 3 (C), an upward displacement is further applied to the stamp unit P, so that the sample S is peeled off together with the stamp unit P from the donor substrate D; further, as shown in fig. 3 (D), the stamp unit P engaged with the sample S is transferred onto the receiver substrate a, and a downward displacement is applied; then, as shown in fig. 3 (E) and (F), after the sample S is brought into contact with the receptor substrate a, the bonding force between the stamp ST and the sample S is reduced by applying an upward displacement to the stamp unit P and adjusting the air pressure in the air chamber 11, and the process of printing the sample S on the receptor substrate a is completed.
In order to obtain a desired engagement force between the stamp unit P and the sample S in the corresponding step in the above-described transfer process, the following design may be made on the design parameters of the stamp unit P and the control parameters of the stamp unit P.
(method of designing and method of manufacturing stamp Unit P according to an embodiment of the present application)
In the separation step of the transfer process, in the longitudinal sectional view shown in fig. 4, the engagement post 22 can be in three states: the outermost two of the junction posts 22 are in a free state with respect to the center line L, the inner two of the transition junction posts 22 with respect to the outermost two of the junction posts 22 are in a stretched state, and the center junction post 22 is in an original length.
The main design parameters of the stamp unit P are illustrated by fig. 4. Specifically, the height of the bonding posts 22 in the initial state is h, the interval between adjacent bonding posts 22 in the initial state is equal and the interval between adjacent bonding posts 22 is g, the diameter of the bonding posts 22 in the initial state is d, and the width of the rigid substrate 1 in the longitudinal section is 2 b. The "longitudinal section" described above passes through the center axes of the rows of the plurality of engagement posts 22, and the plurality of engagement posts 22 are symmetrical with respect to the center line L (shown in fig. 4) of the longitudinal section.
On either side of the centerline L, there are transition junction posts 22 as described above in the junction posts 22 that are not separated from the sample S. In the longitudinal section, the length between the outer edge of the transition joint post 22 and the outer edge of the rigid substrate 1 is set as a separation length l. Further, in the longitudinal section, a distance by which the rigid substrate 1 moves relative to the sample S in a direction away from the sample S is assumed as a displacement v (the displacement v is 0 in an initial state in which the stamp unit P is not operated). Further, let the air pressure of the air chamber 11 in the stamp unit P be Pm. By adjusting the displacement v applied to the stamp unit P during the transfer process and the air pressure P in the stamp unit PmThe separation length l and the engagement force F can be analyzed based on the above-described main design parameters, thereby achieving the adjustment of the interface strength between the stamp unit P and the sample S. Book (I)The applied design method is realized based on the basic idea, and comprises the following steps: and obtaining the system deflection, obtaining the total energy of the system and determining the relation among the parameters.
In the step of obtaining the system deflection, a mechanical model system is established according to the stress of the flexible membrane 2 in the longitudinal section of the seal unit P. Based on the separation length between the stamp unit P and the sample S in the separation step of the transfer process, a portion of the flexible film 2 from the center line L to the outer edge of the transition junction post 22 is defined as a junction section, and a portion of the flexible film 2 from the outer edge of the transition junction post 22 to the outer edge of the rigid substrate 1 is defined as a separation section, whereby the flexible film 2 that is deformed is equivalent to a cantilever beam structure and is divided into the junction section and the separation section. A first deflection in the joint section is calculated based on a differential deflection line equation for the joint section and a second deflection in the separation section is calculated based on a differential deflection line equation for the separation section.
Specifically, the stressed state of the flexible membrane 2 is simplified into a spring cantilever beam structure shown in fig. 5. As shown in FIG. 6, the corresponding OA-stage beam (joint section) is subjected to both the gas pressure pmWhile being subjected to the tensile force of the engagement post 22
And shear force F at the AB section beam (separation section)1And bending moment M1Function of wherein
Associated with deformation of the OA beam; as shown in FIG. 7, for the AB section beam force, only the air pressure pmAnd shear forces F acting on the OA beam and the rigid substrate 1, respectively1、F2And bending moment M1、M2. Thus, is provided with
Is the elastic modulus, I, of the flexible film 2zIs the moment of inertia of the flexible membrane 2,
is the first scratchDegree, x1Is x with the innermost point of the joint section as the origin1O1y1The abscissa in the coordinate system is the axis of the coordinate system,
is a second deflection, x2Is x with the innermost point of the separation section as the origin2O2y2Abscissa in the coordinate system.
Therefore, the differential equation for the deflection line of the OA-stage beam can be written as:
wherein
And define k4＝d/[Izh(d+g)]。
For the analysis of the OA beam, it can be obtained from formula (1):
the general solution for equation (2) is:
for an AB-section beam, similarly, one can get:
the corresponding general solution is:
taking into account the continuity of displacement, angle of rotation, bending moment, shearing force, etcUnder the condition of x1O1y1And x2O2y2Under the coordinate system, can be expressed as:
the equations (3), (5) and (6) are rewritten in the same coordinate system xOy with the innermost point of the OA segment as the origin, and are expressed in terms of x1＝x,y1＝y,x2X- (b-l), and y2＝y-v1The transformation is performed and, in combination with its boundary conditions, it can be rewritten as:
the corresponding boundary conditions are:
according to the formulas (7) and (8), the coefficient C can be obtained by solving1～C8And w1(x) And w2(x) A specific expression of (1), wherein C1～C8Are real numbers.
Further, in the step of obtaining the total energy of the system, a first bending deformation energy of the joined section and a tensile deformation energy of the joined pillars 22 joined to the sample S in the separation step are calculated based on the first deflection obtained above, a second bending deformation energy of the separated section is calculated based on the second deflection, an interface energy between the stamp unit P and the sample S is calculated, and the sum of the first bending deformation energy, the tensile deformation energy, the second bending deformation energy, and the interface energy is taken as the total energy.
Specifically, for the total energy of the system, UtotalIs composed of four parts. 1) Bending deformation energy of OA section beam
2) Of AB beamEnergy of bending deformation
3) Tensile deformation energy U of the bond post 22pillarAnd 4) interfacial energy Uγ. The total energy of the system can therefore be expressed as:
wherein the energy of each part can be expressed as:
bending deformation energy of OA section beam
Bending deformation energy of AB beam
Tensile deformation energy U of the bond post 22pillar
Interfacial energy Uγ
Where γ represents the interface strength between stamp unit P and sample S.
Further, in the step of determining the parameter relationship, the relative relationship between the air pressure in the cavity, the interface strength between the stamp unit P and the sample S, and the displacement and separation length of the rigid substrate 1 relative to the sample S, and the maximum engaging force between the stamp unit P and the sample S are determined using the total energy calculated above, thereby designing the stamp unit P.
The total energy of the system can be obtained based on the above-described correspondence of equations (9) to (13). In addition, let
Is the total energy of the system in a non-dimensionalization way,
is a non-dimensionalized displacement of the displacement,
is a non-dimensionalized separation length,
is the strength of a non-dimensionalized interface,
is a dimensionless air pressure.
As shown in FIG. 8, it can be found that the gas pressure p is obtainedmThe total energy of the system, which is 0 and non-dimensionalized when different displacements are applied, is separated by a non-dimensionalized separation length
A change in (c). When the applied displacement is small, the total energy of the system increases monotonically with increasing separation length, which indicates a separation length of 0. When the minimum value point of the total energy of the system is the minimum value of the energy of the system, the corresponding separation length at the moment is the actual separation length of the system (solid five-pointed star points in fig. 8); and when the local minimum of system energy (the central five-pointed star in FIG. 8) is greater than the system full separation
The system is completely separated at this point. As shown in fig. 9, the same is trueObtain when applying the displacement
And the strength of the interface
The total energy of the system that is not simultaneously non-dimensionalized varies with the length of the separation that is non-dimensionalized. When the system energy is monotonically decreased (as in fig. 9)
And
) At the moment, the system moves in a dimensionless mode
The stamp unit P and the sample S are completely separated. When in
And
the displacement applied at this point is not sufficient to completely separate the sample S from the stamp unit P, but at this point there is a partial separation between the stamp unit P and the sample S, the actual length of the separation being shown in the five-pointed star of fig. 9. As shown in fig. 10, the relationship between total energy and separation length of the system under different air pressure conditions can be obtained in a non-dimensionalized manner, and the meaning is basically the same as that of fig. 8 and 9.
Fig. 11 and 12 show the relationship between the actual separation length of the system and the applied displacement, respectively. As shown in fig. 11, when the air pressure is applied
And the strength of the interface
At different times, the separation length of the system gradually increases with increasing applied displacement, with increasing applied displacement by a certain distanceAnd (4) completely separating the system. When the corresponding system energy is minimum, the separation length of the stamp unit P and the sample S is obtained. When the interface strength is
Under the action of different air pressures, when the separation phenomenon of the system occurs, the applied displacement is the same, and the applied displacement at the moment is defined as critical displacement vcritical. As shown in fig. 12, the system separation length decreases with the same displacement as the air pressure increases.
Thus, the critical displacement required for the system to come apart can be expressed as:
and the interfacial bonding force between stamp unit P and sample S can be expressed as:
substituting a specific expression can solve the specific expression of the bonding force as follows:
the engagement force between the stamp unit P and the sample S is represented by equation (16), and as shown in fig. 13, the maximum engagement force occurs just before separation between the system and the sample S. Thus, the engagement force of the system increases with increasing applied displacement before separation of the system occurs, but the maximum engagement force is related to the critical displacement, so the expression for the maximum engagement force can be expressed as:
and wherein vcriticalIs expressed by the following formula14). Defining a dimensionless maximum engagement force
Wherein FIG. 14 shows the maximum engaging force expressed by the formula (17) and the characteristic size of the stamp unit P
And dimensionless interface strength
The relationship (2) of (c).
Based on this, the maximum engaging force F between the stamp unit P and the sample SmaxAnd the characteristic size of the stamp unit P
Relationship between, separation length l, applied displacement v, interface strength γ and gas pressure pmThe relationship between them is fully available. Therefore, in the actual design and manufacture of the stamp unit P, the design parameters and the usage parameters of the stamp unit P are obtained through the above theoretical calculation, and then the design of the mold M and the manufacture of the stamp unit P are performed according to the obtained design parameters and usage parameters, and the whole manufacturing process is as described in the following steps S1 to S3.
S1: a flexible membrane 2 is manufactured. A casting mold M is manufactured (as shown in fig. 15 and 16, the mold M in fig. 15 corresponds to the flexible film 2 of a single stamp unit P of the above-described embodiment, and the mold M in fig. 16 corresponds to the flexible films 2 of a plurality of stamp units P of the above-described embodiment), the mold M is manufactured by, for example, 3D printing or micro-nano processing, and the mold M is subjected to a mold release treatment. Then the material of the flexible film 2 is selected to be cast, and after solidification, the flexible film is taken out of the mould M. The entire flexible film 2 includes a flexible layer 21 as a substrate and an array of bonding posts 22 provided on the flexible layer 21, wherein tip portions of the bonding posts 22 can be increased by changing a design structure to an array of microstructures such as suction cups.
S2: a rigid substrate 1 is manufactured. The rigid matrix 1 of the seal unit P is machined in a mechanical machining or 3D printing mode, a cavity is formed in the seal unit P, and the cavity comprises an air cavity 11 and an air channel 12. The air passage 12 is mainly an air passage connected to the outside, and the air chamber 11 is inflated and deflated through the air passage 12 to achieve the purpose of subsequently changing the coupling force and separation length between the flexible membrane 2 and the sample S.
S3: the stamp unit P and the stamp ST are manufactured. And connecting the rigid substrate 1 and the flexible film 2 in an adhesive bonding mode to finish the manufacture of the stamp unit P. The stamp unit P can be designed into an array shape to form a stamp ST according to the requirement of actual transfer printing, and programmable transfer printing and interface intensity adjustment are achieved by respectively adjusting the air pressure of each stamp unit P in the array and respectively designing the design parameters of the flexible membrane 2 corresponding to each unit.
Further, the present application also provides a method of testing the coupling force between the stamp unit P and the sample S, which are designed and manufactured using the above-described design method.
(method of testing engagement force between stamp Unit P and sample S according to an embodiment of the present application)
After obtaining relevant dimensional parameters and use parameters by the above design method, the mold M shown in fig. 15 or 16 is manufactured by 3D printing of the photocurable resin material. In the mold M, the concave portion 31 is used to form the flexible layer 21 of the flexible film 2, and the concave hole 32 is used to form the bonding post 22 of the flexible film 2. The flexible film 2 of the stamp unit P of the present application can be obtained by performing a mold release process on the formed product.
Further, a clamp assembly matched with the seal unit P is designed and obtained in a 3D printing or micro-nano processing mode. As shown in fig. 17 to 19, the clamp assembly includes an upper clamp 41 and a lower clamp 42, the upper clamp 41 being used to mount the flexible membrane 2, and the lower clamp 42 being used to carry the sample S.
As shown in fig. 18, the upper jig 41 includes a first clamped portion 411 and an upper jig main body 412. The first clamped portion 411 is positioned above the upper clamp body 412, the first clamped portion 411 is a stretching machine 43 attachment portion of the upper clamp 41, and the first clamped portion 411 and the stretching machine 43 are attached to complete the attachment of the upper clamp 41 and the stretching machine 43. The upper jig main body 412 is formed with a hollow air chamber, and has an opening that opens downward. The periphery of the opening of the upper jig main body 412 is formed as a glue guide groove 413 for receiving glue so that the flexible film 2 and the upper jig 41 can be adhesively fixed. As shown in fig. 19, the lower clip 42 includes a second clamped portion 421 and a lower clip main body 422. The lower clamp body 422 has a slot for inserting the sample S. The second clamped portion 421 is positioned below the lower clamp body 422, and the lower clamp 42 and the stretcher 43 are mounted by attaching the second clamped portion 421 to the stretcher 43. In addition, it is possible to test the coupling force between different samples S and the stamp unit P by changing the kind of the sample S inserted into the lower jig main body 422.
As shown in fig. 17, the distance between the upper and lower clamps 41 and 42 can be changed by the control unit on the right side of the clamp assembly, and the engagement force between the flexible film 2 of the stamp unit P and the sample can be measured to implement the engagement force test between the flexible film 2 of the stamp unit P and the sample S. And comparing the obtained result with the result of the simplified model obtained in the design method to verify, and further verifying the reliability of the design method.
The above description explains the embodiments of the present application in detail, and the present application is also explained as follows.
i. In the design method, various values can be adopted for the design parameters and the use parameters for calculation, so that an optimized design scheme is obtained through the design method. As shown in fig. 8 to 14, to
g＝d＝10-4m，b＝10-2m,h＝10-3m and Iz＝10-9m3These graphs were calculated for the purpose of example.
The mold M and the jigs 41 and 42 referred to in the present application are processed using a 3D printing photocurable resin material, and the material for the flexible film 2 to be manufactured uses Polydimethylsiloxane (PDMS). In addition, the real stamp ST or the stamp unit P is not adopted for testing in the testing process, but the upper clamp 41 is adopted to replace the specific stamp ST, so that the testing method has universal applicability.
The application provides a design method of the seal unit P for transfer printing, the use parameters of the design parameters of the seal unit P are obtained through specific mechanical analysis, the quantitative design of the seal ST can be given, and the controllable adjustment of the transfer printing is more accurate. The stamp unit P manufactured by the method can realize the adjustment of the independent interface bonding strength, and meanwhile, the stamp ST formed by a plurality of stamp units P can realize systematic controllable operation, thereby realizing large-scale programmable transfer printing and realizing complex transfer printing patterns. This application is through theoretical design, carries out optimal design to seal ST from the structural layer face, can greatly reduced rendition to operator's technical requirement, greatly reduced the technical degree of difficulty of operation, make the rendition step convenient easy operation more. The application also provides a method for testing the joint force between the stamp unit P and the sample S, and the method has universal applicability. By replacing the sample S in the lower jig 42, the interface bonding strength test between the stamp ST and various samples S can be realized.
Claims (5)
1. A method of testing a bonding force between a stamp unit and a sample, the method comprising:
manufacturing a flexible film (2), wherein design parameters of the flexible film (2) of the stamp unit (P) are obtained through a design method of the stamp unit (P), and the flexible film (2) with the joint columns (22) is manufactured by utilizing the design parameters;
assembling a flexible membrane (2) and a sample (S), wherein the flexible membrane (2) is assembled to an upper fixture (41) having an air cavity such that the flexible membrane (2) encloses the air cavity and the binding posts (22) face a lower fixture (42), the sample (S) is mounted to the lower fixture (42) and opposite the binding posts (22); and
a test verification in which the engagement post (22) is engaged with the sample (S), an actual engagement force between the stamp unit (P) and the sample (S) is measured by changing the air pressure in the air chamber of the upper jig (41) and the distance between the upper jig (41) and the lower jig (42), and a verification is compared with a theoretical engagement force obtained by the design method,
in the design method, the height of the joint columns (22) is h, the interval between the adjacent joint columns (22) is g, the diameter of the joint columns (22) is d, the width of a rigid base body of the stamp unit (P) in a longitudinal section is 2b, the separation length of the stamp unit (P) and the sample (S) in the longitudinal section is l, and the distance of the rigid base body moving relative to the sample (S) in the longitudinal section towards the direction far away from the sample (S) is displacement v,
let pmIs the air pressure in the air cavity of the rigid substrate,
is the elastic modulus, I, of the flexible film (2)zIs the moment of inertia of the flexible membrane (2), and k4＝d/[Izh(d+g)]，
The theoretical bonding force between the stamp unit (P) and the sample (S) is the following formula 1:
setting a critical displacement of the rigid matrix in the longitudinal section relative to the sample (S) moving in a direction away from the sample (S) as vcriticalWhich is represented by formula 2 below:
wherein γ represents the interface strength between the stamp unit P and the sample S, the maximum theoretical bonding force between the stamp unit P and the sample S is obtained based on the following formula 1 and formula 2, and is represented by formula 3:
2. the method for testing the coupling force between a stamp unit and a sample according to claim 1, wherein in the step of manufacturing the flexible film (2), a mold (M) is manufactured using the design parameters, a film material is cast in the mold (M), and the film material is taken out of the mold (M) after being cured, thereby obtaining the flexible film (2), and the flexible film (2) includes a sheet-shaped flexible layer (21) and a plurality of the coupling posts (22) on one side surface of the flexible layer (21).
3. Method for testing the coupling force between a stamp unit and a sample according to claim 2, characterized in that said mould (M) is made of 3D printed light-curable resin material.
4. The method for testing the coupling force between a stamp unit and a sample according to claim 2 or 3, wherein the film material is polydimethylsiloxane.
5. The method for testing the coupling force between a stamp unit and a sample according to any one of claims 1 to 3, wherein in the step of test verification, the kind of sample (S) on the lower jig (42) is changed, and the actual coupling force between the coupling post (22) and the different kind of sample (S) is measured.
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| CN108583024B (en) * | 2018-07-05 | 2024-04-30 | 浙江大学 | Large-scale programmable active transfer seal based on bionic design and transfer printing method |
| CN109708810A (en) * | 2019-02-21 | 2019-05-03 | 钛深科技(深圳)有限公司 | A kind of apparatus and system for film tactile sensing chip testing |
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