WO2009110440A1

WO2009110440A1 - Method of predicting bend lifetime of laminated body, prediction device of bend lifetime of laminated body, prediction program of bend lifetime of laminated body, and recording medium

Info

Publication number: WO2009110440A1
Application number: PCT/JP2009/053912
Authority: WO
Inventors: 伸悦藤元
Original assignee: 新日鐵化学株式会社
Priority date: 2008-03-04
Filing date: 2009-03-03
Publication date: 2009-09-11
Also published as: TWI460425B; JP5248595B2; JPWO2009110440A1; CN101960283A; KR20100138889A; TW200944793A; CN101960283B

Abstract

A method of predicting the bend lifetime of a laminated body comprising a plurality of layers. Stress occurring in a wiring layer in the virtual laminated body is calculated using respective pieces of information relating to the virtual laminated body: the thickness of each layer constituting the virtual laminated body, the relation between the stress and strain in each layer constituting the virtual laminated body, the interval between a fixed plate and a movable plate in a bend test, and the line width and the line space width in the wiring layer of the virtual laminated body. On the basis of the calculated stress and the relation between the stress and the bend lifetime, the bend lifetime of the virtual laminated body is predicted.

Description

Bending life prediction method for laminated body, bending life prediction apparatus for laminated body, bending life prediction program for laminated body, and recording medium

The present invention relates to a method and apparatus for predicting the bending life of a bendable laminate having a plurality of laminated layers including a base layer and a wiring layer made of a patterned conductor, and bending of the laminate The present invention relates to a program and a recording medium used for predicting a lifetime.

In recent years, flexible printed wiring boards (hereinafter referred to as FPC) are widely used in electronic devices having movable parts such as mobile phones, hard disk devices, and printers. The FPC includes, for example, a base layer, a wiring layer made of a patterned conductor bonded to one surface of the base layer, an adhesive layer covering the wiring layer, and a cover layer bonded to the adhesive layer. And have.

FPCs used in electronic devices having moving parts are required to have high bending resistance. One of the tests for evaluating the bending resistance characteristics of FPC is a bending test called an IPC test. In this bending test, an FPC is bent and inserted in a U shape between a fixed plate and a movable plate arranged at a predetermined interval, and each end in the longitudinal direction of the FPC is fixed to the fixed plate and the movable plate, respectively. This is done by reciprocating the movable plate in a direction parallel to the surface. In this bending test, for example, the number of reciprocating motions of the movable plate from the start of the test until the wiring layer breaks is measured as the bending life.

By the way, when it is desired to design the FPC so as to satisfy the desired bending resistance, it takes a lot of labor, time and cost if the FPC prototype and the bending test are repeated. Therefore, if the bending life of the FPC can be predicted by simulation, it is possible to reduce labor, time and cost.

Conventionally, with regard to a bendable wiring member such as an FPC, methods for predicting bending resistance characteristics such as a bending life by simulation are roughly divided into the following first and second methods. The first method is a method using a master curve and an actual measurement value of a prediction target, as described in Patent Document 1, for example. The second method is a method using a finite element method as described in Patent Document 2 and Patent Document 3, for example.

Patent Document 1 describes a method for predicting the bending life of a composite such as a flat cable. In this method, first, a master that shows the relationship between the maximum distortion amount of the conductor portion of the composite and / or the deviation of the bent shape from the ideal radius when mounted on the bending resistance evaluation test apparatus, and the actually measured bending life. Create a curve. Next, the maximum strain amount of the conductor portion and / or the deviation amount of the bent shape from the ideal radius in the composite body to be predicted mounted on the bending resistance evaluation test apparatus is measured. Next, the maximum distortion amount of the conductor portion and / or the deviation amount of the bent shape from the ideal radius in the measured composite object is collated with the master curve to predict the bending life of the composite object to be predicted. .

Patent Document 2 describes a method for predicting the bending life of an electric wire or electric wire bundle having at least a central conductor wire. In this method, first, a master curve indicating the relationship between the bending life of a single electric wire and the amount of change in strain is obtained. Next, the maximum strain change amount of the central conductor wire of the electric wire or electric wire bundle to be predicted is calculated using the finite element method. Next, the calculated maximum strain variation is collated with the master curve to predict the bending life of the prediction target electric wire or electric wire bundle.

Patent Document 3 describes a method for predicting the bending durability of a plurality of electric wires and a bending protection member attached to a bent portion. In this method, first, a finite element model of each of a plurality of electric wires and a bending protection member is created. Next, the stress in each finite element of the finite element model is calculated. Next, the maximum stress is searched from among the calculated stresses. Next, with reference to the prediction function, the number of bending durability times corresponding to the maximum stress for each of the plurality of electric wires and the bending protection member is acquired, and the shortest bending durability number is obtained from these.

Japanese Unexamined Patent Publication No. 8-166333 Japanese Unexamined Patent Publication No. 2002-260459 Japanese Unexamined Patent Publication No. 2004-191361

By the way, in a bendable laminate having a plurality of layers such as FPC, a number of configurations can be considered by changing the conditions of the plurality of layers. Repeating trial production and bending test for each of such a large number of configurations requires a great deal of labor, time and cost. Therefore, if you want to design a laminate that has the desired bending life, if you can simulate the prediction of the bending life by arbitrarily setting the conditions of each layer that makes up the laminate, you can significantly reduce labor, time, and cost. It becomes possible to reduce. Further, if such a simulation is possible, it is possible to easily obtain a preferable combination of conditions of each layer constituting the laminated body.

However, in the first method of the conventional methods for predicting the bending resistance such as the bending life by simulation, since the actual measurement value of the prediction target is used, the condition of each layer constituting the laminate is arbitrarily set and the simulation is performed. There is a problem that cannot be performed. In the first method, it is also impossible to obtain a preferable combination of conditions for each layer constituting the stacked body using simulation.

In addition, the second method of the conventional methods for predicting the bending resistance such as the bending life by simulation uses the finite element method, so that it takes a lot of time and labor to create a finite element model. is there.

SUMMARY OF THE INVENTION An object of the present invention is to easily set a bending life prediction method for a laminated body and a bending life prediction apparatus for a laminated body by arbitrarily setting the conditions of each layer constituting the laminated body and predicting the bending life of the laminated body. Another object of the present invention is to provide a bending life prediction program for a laminate and a recording medium.

The method for predicting the bending life of a laminate of the present invention has a plurality of laminated layers including a base layer and a wiring layer made of a patterned conductor, extends in one direction, and is a bendable laminate. The laminate is bent and inserted in a U shape between a fixed plate and a movable plate arranged at a predetermined interval, and each end in the longitudinal direction of the laminate is fixed to the fixed plate and the movable plate, respectively. This is a method for predicting a bending life to be measured by a bending test performed by reciprocating a plate in a direction parallel to its surface.

The bending life prediction method of the laminate of the present invention is
For each of a plurality of laminate samples having different configurations, the thickness of each layer constituting the sample, the relationship between stress and strain in each layer constituting the sample, the interval between the fixed plate and the movable plate in the bending test, A first calculation procedure for calculating a stress generated in the wiring layer of the sample using each information of the line width and the line width in the wiring layer;
For each of a plurality of samples, a procedure for measuring the bending life by a bending test,
Based on the stress generated in the wiring layer of each sample calculated by the first calculation procedure and the bending life of each sample measured by the procedure of measuring the bending life, the wiring layer in the laminated body having an arbitrary configuration is generated. A procedure for determining the relationship between stress and flex life,
Regarding the virtual laminate that is the object of predicting the flex life, the thickness of each layer constituting the virtual laminate, the relationship between the stress and strain in each layer constituting the virtual laminate, and the fixed plate and the movable plate in the bending test A second calculation procedure for calculating the stress generated in the wiring layer of the virtual laminate, using the information of the line width and the inter-line width in the wiring layer of the virtual laminate,
Based on the stress generated in the wiring layer of the virtual laminate calculated by the second calculation procedure, and the relationship between the stress and the flex life determined by the procedure for obtaining the relationship between the stress and the flex life, the virtual stack And a procedure for predicting the flexion life of the body.

In the method for predicting the bending life of the laminate of the present invention, the elastic modulus of the material constituting each layer may be used as the relationship between stress and strain in each layer.

Further, in the method for predicting the bending life of the laminate of the present invention, the relationship between stress and strain in each layer may be obtained by a tensile test on the material constituting each layer.

Further, in the bending life prediction method of the laminate of the present invention, in the first calculation procedure, the main stress obtained from the normal stress and the shear stress is calculated as the stress generated in the wiring layer of the sample, and in the second calculation procedure, As a stress generated in the wiring layer of the virtual laminate, a main stress obtained from a normal stress and a shear stress may be calculated.

In the method for predicting the flexing life of the laminate of the present invention, in the procedure for obtaining the relationship between the stress and the flexing life, the relationship between the stress generated in the wiring layer and the flexing life using the temperature when the flexing test is performed as a parameter. In the procedure for obtaining the bending life and predicting the bending life, the virtual lamination under an arbitrary temperature is based on the stress calculated by the second calculation procedure and the relationship between the stress and the bending life using the temperature as a parameter. The flexion life of the body may be predicted.

Further, in the method for predicting the bending life of the laminate of the present invention, in the procedure for obtaining the relationship between the stress and the bending life, the stress generated in the wiring layer and the bending life using the frequency of the reciprocating motion of the movable plate in the bending test as parameters. In the procedure for calculating the relationship between the bending life and the bending life, the virtual life under an arbitrary frequency is calculated based on the stress calculated by the second calculation procedure and the relationship between the stress using the frequency as a parameter and the bending life. The bending life of the laminate may be predicted.

The bending life prediction apparatus for a laminate according to the present invention has a plurality of laminated layers including a base layer and a wiring layer made of a patterned conductor, extends in one direction, and is a bendable laminate. The laminate is bent and inserted in a U shape between a fixed plate and a movable plate arranged at a predetermined interval, and each end in the longitudinal direction of the laminate is fixed to the fixed plate and the movable plate, respectively. It is a device that predicts the bending life to be measured by a bending test performed by reciprocating a plate in a direction parallel to its surface.

The bending life prediction apparatus of the laminate of the present invention is
For each of a plurality of laminate samples having different configurations, the thickness of each layer constituting the sample, the relationship between stress and strain in each layer constituting the sample, the interval between the fixed plate and the movable plate in the bending test, First input means for inputting information on the line width and the line width in the wiring layer;
First calculation means for calculating stress generated in the wiring layer of the sample using information input by the first input means;
A second input means for inputting the bending life of each of the plurality of samples measured by the bending test;
Based on the stress generated in the wiring layer of each sample calculated by the first calculation means and the bending life of each sample input by the second input means, the stress generated in the wiring layer in the laminate having an arbitrary configuration Means for determining the relationship between the bending life and
Regarding the virtual laminate that is the object of predicting the flex life, the thickness of each layer constituting the virtual laminate, the relationship between the stress and strain in each layer constituting the virtual laminate, and the fixed plate and the movable plate in the bending test A third input means for inputting information on each of the interval and the line width and the inter-line width in the wiring layer of the virtual laminate,
Using the information input by the third input means, second calculation means for calculating the stress generated in the wiring layer of the virtual laminate,
Based on the stress generated in the wiring layer of the virtual laminated body calculated by the second calculating means and the relationship between the stress and the bending life obtained by the means for obtaining the relation between the stress and the bending life, Means for predicting the flexion life of the body.

In the bending life prediction apparatus for a laminate according to the present invention, the first calculation means calculates the main stress obtained from the normal stress and the shear stress as the stress generated in the wiring layer of the sample, and the second calculation means As the stress generated in the wiring layer of the laminated body, the main stress obtained from the normal stress and the shear stress may be calculated.

Further, in the bending life prediction apparatus of the laminate of the present invention, the means for obtaining the relationship between the stress and the bending life is the relationship between the stress generated in the wiring layer and the bending life with the temperature when the bending test is performed as a parameter. And calculating the bending life based on the stress calculated by the second calculating means and the relationship between the stress and the bending life with the temperature as a parameter and the virtual lamination under an arbitrary temperature. The flexion life of the body may be predicted.

Further, in the bending life prediction apparatus of the laminate of the present invention, the means for obtaining the relationship between the stress and the bending life is the stress generated in the wiring layer and the bending life using the frequency of the reciprocating motion of the movable plate in the bending test as a parameter. The means for calculating the relationship between the bending life and the bending life is calculated based on the stress calculated by the second calculation means and the relationship between the stress and the bending life with the frequency as a parameter. The bending life of the laminate may be predicted.

The bending life prediction program for a laminated body of the present invention has a plurality of laminated layers including a base layer and a wiring layer made of a patterned conductor, extends in one direction, and can be bent. The laminate is bent and inserted in a U shape between a fixed plate and a movable plate arranged at a predetermined interval, and each end in the longitudinal direction of the laminate is fixed to the fixed plate and the movable plate, respectively. A program for causing a computer to function as the following means for predicting a bending life to be measured by a bending test performed by reciprocating a plate in a direction parallel to the surface.

The bending life prediction program for a laminate according to the present invention includes a computer,
For each of a plurality of laminate samples having different configurations, the thickness of each layer constituting the sample, the relationship between stress and strain in each layer constituting the sample, the interval between the fixed plate and the movable plate in the bending test, A first input means for inputting information on the line width and the inter-line width in the wiring layer;
First calculation means for calculating stress generated in the wiring layer of the sample using information input by the first input means;
A second input means for inputting the bending life of each of the plurality of samples measured by the bending test;
Based on the stress generated in the wiring layer of each sample calculated by the first calculation means and the bending life of each sample input by the second input means, the stress generated in the wiring layer in the laminate having an arbitrary configuration Means for determining the relationship between the bending life and
Regarding the virtual laminate that is the object of predicting the flex life, the thickness of each layer constituting the virtual laminate, the relationship between the stress and strain in each layer constituting the virtual laminate, and the fixed plate and the movable plate in the bending test A third input means for inputting each information of the interval between the line width and the line width in the wiring layer of the virtual laminate,
Second calculation means for calculating the stress generated in the wiring layer of the virtual laminate using the information input by the third input means, and the wiring layer of the virtual laminate calculated by the second calculation means And a means for predicting the bending life of the virtual laminate based on the relationship between the stress generated in the stress and the relation between the stress and the bending life obtained by the means for obtaining the relationship between the stress and the bending life.

The computer-readable recording medium of the present invention records the bending life prediction program for the laminate of the present invention.

According to the method for predicting the bending life of the laminate, the bending life prediction apparatus for the laminate, the bending life prediction program for the laminate, or the recording medium of the present invention, the thickness of each layer constituting the virtual laminate and the virtual laminate The relationship between the stress and strain in each layer constituting the virtual laminate, the distance between the fixed plate and the movable plate in the bending test, and the line width and the inter-line width in the wiring layer of the virtual laminate, It is possible to calculate the stress generated in the wiring layer of the virtual laminate and predict the flex life of the virtual laminate based on the calculated stress and the relationship between the stress and the flex life. Thereby, according to this invention, it becomes possible to set the conditions of each layer which comprises a laminated body arbitrarily, and to predict the bending life of a laminated body easily.

Other objects, features and benefits of the present invention will become fully apparent with the following description.

It is a perspective view which shows a part of laminated body in one embodiment of this invention. It is a top view which shows the wiring layer of the laminated body in one embodiment of this invention. It is explanatory drawing which shows the state which mounted | wore the bending test apparatus used for a bending test with the laminated body. It is a block diagram which shows the structure of the computer which implement | achieves the bending life prediction apparatus which concerns on one embodiment of this invention. It is a functional block diagram which shows the function structure of the bending life prediction apparatus which concerns on one embodiment of this invention. It is a flowchart which shows the bending life prediction method of the laminated body which concerns on one embodiment of this invention. It is sectional drawing of the model of the laminated body used for description of the calculation method of the stress in one embodiment of this invention. FIG. 6 is a characteristic diagram showing a relationship between a principal stress and a bending life represented by a stress-bending life relational expression in an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Laminated body, 11 ... Base layer, 12 ... Wiring layer, 13 ... Adhesive layer, 14 ... Cover layer, 21 ... Fixed plate, 22 ... Movable plate, 30 ... Bending life prediction apparatus.

Hereinafter, a flexural life prediction method for a laminate, a flexural life prediction apparatus for a laminate, a flexural life prediction program for a laminate, and a recording medium according to an embodiment of the present invention will be described in detail with reference to the drawings. First, the laminated body in this Embodiment is demonstrated. The laminated body in this embodiment has a plurality of laminated layers including a base layer and a wiring layer made of a patterned conductor, extends in one direction, and can be bent. As such a laminated body, there exists FPC (flexible printed wiring board), for example.

Here, with reference to FIG. 1 and FIG. 2, an example of the structure of the laminated body in this Embodiment is demonstrated. FIG. 1 is a perspective view showing a part of the laminate. In FIG. 1, the hatched surface represents a cross section. FIG. 2 is a plan view showing a wiring layer of the laminate. The laminate shown in FIGS. 1 and 2 is specifically an FPC. However, this FPC is a test FPC used for measuring a flex life by a flex test.

As shown in FIG. 1, the laminate 1 includes a base layer 11, a wiring layer 12 made of a patterned conductor joined to one surface of the base layer 11, and an adhesive layer covering the wiring layer 12. 13 and a cover layer 14 bonded to the adhesive layer 13. The laminate 1 extends in one direction and can be bent. The laminated body 1 may further include another adhesive layer disposed between the base layer 11 and the wiring layer 12.

As shown in FIG. 2, the wiring layer 12 has a meander shape. More specifically, the wiring layer 12 includes two adjacent linear portions 12a extending in the longitudinal direction of the laminate 1 (left and right direction in FIG. 2) and two adjacent wiring layers 12 so that the entire wiring layer 12 has a meander shape. It has the connection part 12b which connects the edge parts of the linear part 12a. Here, the width of the linear portion 12a (the vertical dimension in FIG. 2) is defined as a line width LW, and the interval between two adjacent linear portions 12a is defined as a line width SW.

As the material of the base layer 11 and the cover layer 14, a resin such as a polyimide resin is used. As a material of the wiring layer 12, a metal such as copper is used. As the material of the adhesive layer 13, a synthetic adhesive such as an epoxy adhesive or an acrylic adhesive is used.

In the following description, the terms “laminate sample”, “arbitrary laminate”, and “virtual laminate” are used in relation to the laminate 1. The “laminate sample” is actually produced in order to create a stress-bending life relationship as a relation between the stress generated in the wiring layer 12 and the flexing life in a laminated body having an arbitrary configuration described later. It is the laminated body 1 which is. “Arbitrary laminated body” is an imaginary laminated body 1 in which conditions other than the minimum requirements of the laminated body 1 are not specified. The “virtual laminated body” is an imaginary laminated body 1 that is a target for predicting a flex life. The “virtual laminate” includes the thickness of each layer constituting the laminate 1, the relationship between stress and strain in each layer constituting the laminate 1, the distance between the fixed plate and the movable plate in the bending test, It is specified by each information of the line width LW and the line width SW in the wiring layer 12. Hereinafter, in order to distinguish between “laminate sample”, “arbitrary laminate”, and “virtual laminate”, “laminate sample” is denoted by reference numeral 1A, and “arbitrary laminate” The “body” is denoted by reference numeral 1B, and the “virtual stacked body” is denoted by reference numeral 1C.

Next, a bending test for measuring the bending life of the laminate 1 will be described with reference to FIG. FIG. 3 is an explanatory view showing a state in which the laminate 1 is mounted on a bending test apparatus used for a bending test. The bending test apparatus includes a fixed plate 21 and a movable plate 22 that are arranged with a predetermined interval H therebetween. In the bending test, the laminate 1 is bent in a U shape between the fixed plate 21 and the movable plate 22 and the longitudinal ends of the laminate 1 are fixed to the fixed plate 21 by the

fixtures

23 and 24, respectively. The movable plate 22 is fixed to the movable plate 22, and the movable plate 22 is reciprocated in a direction parallel to the surface. In the bending test, the wiring layer 12 is energized and the resistance value of the wiring layer 12 is detected. Then, when the resistance value of the wiring layer 12 becomes equal to or higher than a predetermined value, it is determined that the wiring layer 12 is broken. In the bending test, the number of reciprocating motions of the movable plate 22 from the start of the test until the wiring layer 12 breaks, that is, until the resistance value of the wiring layer 12 becomes a predetermined value or more is measured as the bending life.

Next, the bending life prediction apparatus according to the present embodiment will be described with reference to FIG. 4 and FIG. The bending life prediction apparatus 30 according to the present embodiment is an apparatus that predicts the bending life to be measured for the laminate 1 by the above-described bending test. The bending life prediction apparatus 30 is realized using a computer.

FIG. 4 is a block diagram showing a configuration of a computer 30C that realizes the bending life prediction apparatus 30. As shown in FIG. 4, the computer 30 </ b> C includes a main control unit 31, an input device 32, an output device 33, a display device 34, a storage device 35, and a bus 36 that connects them to each other. . The main control unit 31 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). The storage device 35 is not particularly limited as long as it can store information, but is, for example, a hard disk device or an optical disk device. The storage device 35 records information on a computer-readable recording medium 37 and reproduces information from the recording medium 37. The recording medium 37 may be in any form as long as it can store information, but is, for example, a hard disk or an optical disk. The recording medium 37 may be a recording medium in which the bending life prediction program for the laminate according to the present embodiment is recorded.

FIG. 5 is a functional block diagram showing a functional configuration of the bending life prediction apparatus 30. As shown in FIG. As shown in FIG. 5, the bending life prediction apparatus 30 includes a first input means 41, a first calculation means 42, a second input means 43, a stress-bending life relational expression creating means 44, A third input unit 45, a second calculation unit 46, and a bending life prediction unit 47 are provided.

The first input means 41 includes, for each of a plurality of laminate samples 1A having different configurations, the thickness of each layer constituting the sample 1A, the relationship between the stress and strain in each layer constituting the sample 1A, and the bending test. Information on the distance H between the fixed plate 21 and the movable plate 22, and the line width LW and the line width SW in the wiring layer 12 of the sample 1A are input. The first calculation means 42 uses the information input by the first input means 41 to calculate the stress generated in the wiring layer 12 of the sample 1A. The second input means 43 inputs the bending life of each of the plurality of samples 1A measured by the bending test.

The stress-bending life relation formula creating means 44 includes the stress generated in the wiring layer 12 of each sample 1A calculated by the first calculating means 42 and the bending life of each sample 1A input by the second input means 43. Based on the above, the relationship between the stress generated in the wiring layer 12 in the laminate 1B having an arbitrary configuration and the flex life is obtained. Specifically, the stress-bending life relation formula creating means 44 creates a stress-bending life relation formula as a relation between the stress generated in the wiring layer 12 and the flex life in the laminate 1B having an arbitrary configuration. The stress-bending life relationship formula creating means 44 corresponds to “means for obtaining the relationship between stress and bending life” in the present invention.

The third input means 45 includes, for the virtual laminate 1C, the thickness of each layer constituting the virtual laminate 1C, the relationship between the stress and strain in each layer constituting the virtual laminate 1C, and the fixed plate in the bending test. Information on the distance H between the movable plate 22 and the line width LW and the line width SW in the wiring layer 12 of the virtual laminate 1C is input. The second calculation means 46 uses the information input by the third input means 45 to calculate the stress generated in the wiring layer 12 of the virtual laminate 1C.

The bending life prediction means 47 is a stress-bending life relational expression created by the stress generated in the wiring layer 12 of the virtual laminate 1C calculated by the second calculation means 46 and the stress-bending life relation creating means 44. Based on the above, the bending life of the virtual laminate 1C is predicted.

The program for predicting the bending life of the laminate according to the present embodiment shows the computer 30C shown in FIG. 4 in order to predict the bending life to be measured for the laminate 1 by the above-described bending test. It functions as each means. The bending life prediction program for the laminate is recorded in the recording medium 37 in FIG. 4 or the ROM in the main control unit 31.

Next, the bending life prediction method for the laminate according to this embodiment will be described. The bending life prediction method of the laminated body according to the present embodiment is a method of predicting the bending life to be measured for the laminated body 1 by the above-described bending test.

FIG. 6 is a flowchart showing a method for predicting the bending life of the laminate according to the present embodiment. As shown in FIG. 6, in the bending life prediction method for a laminate according to the present embodiment, first, for each of a plurality of laminate samples 1A having different configurations, the thickness of each layer constituting sample 1A, Using information on the relationship between stress and strain in each layer constituting the sample 1A, the distance H between the fixed plate 21 and the movable plate 22 in the bending test, and the line width LW and the line width SW in the wiring layer 12 of the sample 1A. Then, the stress generated in the wiring layer 12 of the sample 1A is calculated (step S101). This step S101 corresponds to the first calculation procedure in the present invention. Next, the bending life of each of the plurality of samples 1A is measured by a bending test (step S102).

Next, based on the stress generated in the wiring layer 12 of each sample 1A calculated in step S101 and the bending life of each sample 1A measured in step S102, the wiring layer 12 in the laminate 1B having an arbitrary configuration As a relationship between the generated stress and the flex life, a stress-flex life relationship is obtained (step S103).

Next, for the virtual laminate 1C, the thickness of each layer constituting the virtual laminate 1C, the relationship between the stress and strain in each layer constituting the virtual laminate 1C, and the fixed plate 21 and the movable plate 22 in the bending test. The stress generated in the wiring layer 12 of the virtual laminate 1C is calculated using the information of the interval H and the line width LW and the inter-line width SW in the wiring layer 12 of the virtual laminate 1C (step S104). This step S104 corresponds to the second calculation procedure in the present invention.

Next, based on the stress generated in the wiring layer 12 of the virtual laminate 1C calculated in step S104 and the relationship between the stress obtained in step S103 and the flex life, the flex life of the virtual laminate 1C is calculated. Prediction is made (step S105).

The bending life of the virtual laminate 1C is predicted by the above steps (processes). Note that the order of step S101 and step S102 may be reversed from the above description.

Next, the operation of the bending life prediction device 30 when the bending life prediction device 30 according to the present embodiment realizes the above-described bending life prediction method for a laminate will be described. In step S101, first, the thickness of each layer constituting the sample 1A and the stress and strain in each layer constituting the sample 1A are measured by the first input means 41 for each of the samples 1A of the plurality of stacked bodies 1 having different configurations. , The distance H between the fixed plate 21 and the movable plate 22 in the bending test, and the line width LW and the line width SW in the wiring layer 12 of the sample 1A are input. Next, the stress generated in the wiring layer 12 of the sample 1 </ b> A is calculated by the first calculation unit 42 using the information input by the first input unit 41.

In step S102, the bending life of each of the plurality of samples 1A measured by the bending test is input by the second input means 43.

In step S103, based on the stress generated in the wiring layer 12 of each sample 1A calculated by the first calculation means 42 and the bending life of each sample 1A input by the second input means 43, stress-bending is performed. The life relation formula creating means 44 creates a stress-bending life relation formula as a relation between the stress generated in the wiring layer 12 and the flex life in the laminate 1B having an arbitrary configuration.

In step S104, the third input unit 45 causes the virtual laminated body 1C to have a thickness of each layer constituting the virtual laminated body 1C, a relationship between stress and strain in each layer constituting the virtual laminated body 1C, and bending. Information on the distance H between the fixed plate 21 and the movable plate 22 in the test and the line width and the line width in the wiring layer 12 of the virtual laminate 1C are input. Next, the stress generated in the wiring layer 12 of the virtual laminate 1C is calculated by the second calculation unit 46 using the information input by the third input unit 45.

In step S105, based on the stress generated in the wiring layer 12 of the virtual laminated body 1C calculated by the second calculation means 46 and the stress-bending life relation formula created by the stress-bending life relation formula creation means 44. Thus, the bending life prediction means 47 predicts the bending life of the virtual laminate 1C.

Hereinafter, the bending life prediction method for the laminate according to the present embodiment will be described in more detail. First, a method for calculating the stress generated in the wiring layer 12 in steps S101 and S104 will be described in detail with reference to FIG. FIG. 7 is a cross-sectional view of a model of the laminate 1 used for explaining the stress calculation method. For convenience, FIG. 7 shows a model in which the laminate 1 has three layers, but the following description applies to the case where the laminate has two or more layers. Here, the number of layers of the stacked body 1 is n (n is an integer of 2 or more). In addition, the i-th (i = 1, 2,..., N) layer counted from the bottom among the layers constituting the laminate 1 is referred to as an i-th layer. In FIG. 7, the symbol B represents the width of the stacked body 1. The width here is a dimension in a direction parallel to the lower surface of the first layer and perpendicular to the longitudinal direction of the laminate 1.

In the laminated body 1 in the present embodiment, the wiring layer 12 is patterned as shown in FIG. 2, for example. Therefore, when the laminated body 1 is viewed from above, the laminated body 1 includes the wiring layer 12. There are portions where the wiring layer 12 does not exist. Here, a portion where the wiring layer 12 exists is called a wiring portion, and a portion where the wiring layer 12 does not exist is called a space portion. The wiring part and the space part have different configurations. For example, in the case of the laminated body 1 shown in FIG. 1, the wiring part is composed of four layers, and the space part is composed of three layers. Therefore, hereinafter, the wiring portion and the space portion are considered separately as necessary.

[Calculation of neutral plane position]
Here, the lower surface of the first layer is defined as a reference surface SP. Hereinafter, the case where the laminated body 1 is bent so that the reference plane SP has a convex shape on the lower side in FIG. 7 will be considered. In FIG. 7, the symbol NP represents the neutral surface of the laminate 1. Here, the distance between the neutral plane NP and the reference plane SP is defined as a neutral plane position [NP], and the neutral plane position [NP] is calculated separately for the wiring portion and the space portion. The neutral plane position [NP] is calculated by the following equation (1).

_{^{[NP] = Σ i = 1}} n E i B i h i t i / Σ i = 1 n E i B i t i ... (1)

Here, E _i is the elastic modulus of the material constituting the i-th layer. This elastic modulus E _i corresponds to “relation between stress and strain in each layer” in the present embodiment. B _i is the width of the i-th layer and corresponds to the width B shown in FIG. When obtaining the neutral plane position [NP] of the wiring portion, the value of the line width LW is used as B _i , and when obtaining the neutral plane position [NP] of the space portion, the line width SW as B _i. The value of is used. h _i is the distance between the center plane of the i-th layer and the reference plane SP. The central surface of the i-th layer is a virtual surface located at the center in the thickness direction of the i-th layer. t _i is the thickness of the i-th layer. Further, the symbol “Σ _{i = 1} ⁿ ” represents the sum of i from 1 to n. Hereinafter, the neutral plane position of the wiring portion is referred to as [NP] _Line .

[Calculation of effective curvature radius]
Next, as shown in FIG. 3, the effective curvature radius R of the wiring portion at the bent portion of the multilayer body 1 when the multilayer body 1 is inserted in a U shape between the fixed plate 21 and the movable plate 22. Calculate The effective curvature radius R is a distance from the bending center of the bent portion of the laminate 1 to the neutral plane NP of the wiring portion. The effective radius of curvature R is calculated from the distance H between the fixed plate 21 and the movable plate 22 and the neutral plane position [NP] _{Line of the} wiring portion by the following equation (2).

R = H / 2- [NP] _Line (2)

[Calculation of bending normal stress]
Next, a bending normal stress σc that is a maximum tensile normal stress in the longitudinal direction generated in the wiring layer 12 by pure bending is calculated. The bending normal stress σc is calculated by the following equation (3).

σc = Ec (yc− [NP] _Line ) / R (3)

Here, Ec is the elastic modulus of the wiring layer 12. yc is the distance from the reference plane SP to the surface (here, the lower surface) that becomes convex when bent between the upper surface and the lower surface of the wiring layer 12.

[Calculation of equivalent bending stiffness]
Next, an equivalent bending stiffness [BR] that is the bending stiffness of the entire laminate 1 is calculated. The equivalent bending stiffness [BR] is calculated by the following equation (4).

[BR] = B _Line {Σ _{i = 1} ⁿ E _i (a _i ³ −b _i ³ ) / 3} _Line
+ B _Space {Σ _{i = 1} ⁿ E _i (a _i ³ −b _i ³ ) / 3} _Space (4)

Here, B _Line is the sum of the line widths LW, and B _Space is the sum of the line widths SW. Further, as shown in FIG. 7, a _i is the distance between the upper surface of the i-th layer and the neutral plane NP, and b _i is the distance between the lower surface of the i-th layer and the neutral plane NP. {Σ _{i = 1} ⁿ E _i (a _i ³ −b _i ³ ) / 3} _Line is a value of E _i (a _i ³ −b _i ³ ) / 3 in the wiring section, where i is 1 to n It is the sum. {Σ _{i = 1} ⁿ E _i (a _i ³ −b _i ³ ) / 3} _Space is a value of E _i (a _i ³ −b _i ³ ) / 3 in the space part, where i is 1 to n It is the sum. Although related to equation (4), for the i-th layer, B _i (a _i ³ -b _i ³ ) / 3 is a parameter that represents the geometric characteristic of the cross section, generally called the cross-section second moment. . A value obtained by multiplying the cross-sectional second moment of the i-th layer by the elastic modulus of the i-th layer is the bending rigidity of the i-th layer.

[Calculation of bending moment]
Next, the bending moment M of the laminate 1 is calculated. The bending moment M is calculated by the following equation (5).

M = [BR] / R ... (5)

[Calculation of shear stress]
Next, the shear stress τ generated in the laminate 1 is calculated. The shear stress τ is calculated by the following equation (6).

Τ = kM / LeA (6)

Where k is the shear correction factor. When the effective radius of curvature R in the bending test is about 1 mm, a value of 5/6, which is generally used as a primary shear correction coefficient, is used as the value of k. Le is a half value of the circumference of the effective bent portion. A is the cross-sectional area of the laminate 1 perpendicular to the longitudinal direction of the laminate 1.

Next, the principal stress S generated in the wiring layer 12 is calculated. The main stress S is calculated by the following equation (7).

S = (σc / 2) + √ {(σc / 2) ² + τ ² } (7)

In this way, the main stress S as the stress generated in the wiring layer 12 is calculated from the vertical stress σc and the shear stress τ. Further, as described above, the principal stress S is the thickness of each layer constituting the laminated body 1, the relationship between the stress and strain (elastic modulus) in each layer constituting the laminated body 1, and the fixed plate 21 in the bending test. And the distance H between the movable plate 22 and the information on the line width LW and the line width SW in the wiring layer 12.

In step S101, the principal stress S generated in the wiring layer 12 is calculated for each of a plurality of laminate samples 1A having different configurations by the above method. In step S104, the principal stress S generated in the wiring layer 12 is calculated by the above method for the virtual laminated body 1C that is a target for predicting the bending life.

In step S102, the bending life N of each of the plurality of samples 1A is measured by the bending test described with reference to FIG. Let f be the frequency of the reciprocating motion of the movable plate 22 in this bending test. Also, T is the temperature at which the bending test is performed. The bending test may be performed with the frequency f and the temperature T being constant for all the samples 1A, or may be performed with at least one of the frequency f and the temperature T being different for each sample 1A. Alternatively, a plurality of types of samples 1A are prepared for each type, and a bending test is performed on each of the plurality of samples 1A of one type by changing at least one of frequency f and temperature T. Good. When a bending test is performed on a plurality of samples 1A with at least one of the frequency f and the temperature T being different, the stress-bending life relation equation created in step S103 is used, and at least one of the frequency f and the temperature T is a parameter. It becomes possible to make it a function.

Next, a method for obtaining a stress-bending life relationship as a relationship between the stress generated in the wiring layer 12 and the bending life in the laminated body 1B having an arbitrary configuration in step S103 will be described. As a result of obtaining the main stress S and bending life generated in the wiring layer 12 for a number of samples 1A, the relationship between the main stress S generated in the wiring layer 12 and the bending life N for the laminate 1B having an arbitrary configuration is as follows. It was found that it can be approximated by equation (8). Therefore, in the present embodiment, the following equation (8) is a stress-bending life relationship expression that represents the relationship between the principal stress S generated in the wiring layer 12 and the bending life N in the laminate 1B having an arbitrary configuration. The relationship between the principal stress S and the bending life N expressed by the equation (8) is as shown in FIG.

N = α · (f ^χ / S ^β ) · exp (δ / T) (8)

Here, α, β, χ, and δ are physical property parameters (constants). In step S103, α, β, χ, δ are obtained by the least square method so that the equation (8) becomes an equation that approximates the data of the principal stress S and the bending life N generated in the wiring layer 12 for the plurality of samples 1A. Determine the value of. Thereby, Formula (8) becomes a formula showing the relation between principal stress S and bending life N about layered product 1B of arbitrary composition.

In step S105, the principal stress S generated in the wiring layer 12 of the virtual laminate 1C calculated in step S104 is substituted into the above equation (8) obtained in step S103, whereby the virtual laminate 1C. The bending life N is calculated. In the equation (8), when at least one of the temperature T and the frequency f is a parameter, when calculating the bending life N of the virtual laminate 1C, the value of the parameter is specified, Substitute into equation (8).

When the bending test is performed on the plurality of samples 1A with the frequency f and the temperature T being fixed values, and the equation (8) is created using the data obtained by the bending test, the equation (8) Is an equation representing the relationship between the principal stress S and the bending life N when the bending test is performed under the condition where the frequency f and the temperature T are the above-described constant values. In this case, using Equation (8), predict the bending life N when the bending test is performed on the virtual laminated body 1C under the conditions where the frequency f and the temperature T are the above-described constant values, respectively. Is possible.

When the frequency f is set to a constant value, the temperature T is changed, the bending test is performed on the plurality of samples 1A, and the equation (8) is created using the data obtained by the bending test, the equation (8) ) Is an expression representing the relationship between the principal stress S and the bending life N, using the temperature T as a parameter when the bending test is performed under the condition that the frequency f is the above-mentioned constant value. In this case, the bending life N in the case where the bending test is performed on the virtual laminated body 1C using the equation (8) under the condition that the frequency f is the above-described constant value at an arbitrary temperature T. Can be predicted.

When the temperature T is set to a constant value, the frequency f is changed, the bending test is performed on the plurality of samples 1A, and the formula (8) is created using the data obtained by the bending test, the formula (8 ) Is an expression representing the relationship between the principal stress S and the bending life N using the frequency f as a parameter when the bending test is performed under the condition where the temperature T is the above constant value. In this case, the bending life N in the case where the bending test is performed on the virtual laminated body 1C using the equation (8) under the condition that the temperature T is the above-described constant value under an arbitrary frequency f. Can be predicted.

When the bending test is performed on the plurality of samples 1A by changing both the frequency f and the temperature T, and the equation (8) is created using the data obtained by the bending test, the equation (8) is This is an equation representing the relationship between the principal stress S and the bending life N, with the frequency f and the temperature T as parameters. In this case, it is possible to predict the bending life N when the bending test is performed on the virtual laminated body 1C under an arbitrary temperature T and an arbitrary frequency f using the equation (8). .

In the description using the formulas (1) to (7), the elastic modulus of the material constituting each layer is used as the relationship between the stress and the strain in each layer constituting the laminate 1, but the laminate 1 is constituted. The relationship between stress and strain in each layer may be obtained by a tensile test on the material constituting each layer. Specifically, what is acquired by the tensile test on the material constituting each layer is actually measured data (hereinafter referred to as SS curve) of the relationship between stress and strain acquired by the tensile test.

Hereinafter, an example of a method for calculating the main stress S generated in the wiring layer 12 when the SS curve is used as the relationship between stress and strain in each layer will be described. In this method, first, an SS curve is obtained by performing a tensile test on each of the materials (hereinafter referred to as constituent materials) constituting each layer. Next, the laminate 1 is divided into a plurality of calculation steps that are sufficiently fine so that the calculation does not diverge from the straight state to the bent state in the bending test. Next, the slope for each calculation step is calculated in the SS curve of each constituent material. The inclination for each calculation step is the elastic modulus for each calculation step in each constituent material. Next, the elastic modulus for each calculation step in each constituent material thus obtained is used in place of the elastic modulus used in the series of calculations of Equations (1) to (7), and an updated Lagrangian method is used. From the straight state of the laminate 1 to the bent state at the time of the bending test, the series of calculations of the formulas (1) to (7) are repeatedly performed for each calculation step, and wiring is performed in the bent state at the time of the bending test. The principal stress S generated in the layer 12 is calculated. According to the calculation method of the principal stress S using such an updated Lagrangian method, the principal stress S can be accurately calculated even when the relationship between stress and strain (SS curve) in each layer is nonlinear. become.

As described above, according to the present embodiment, for the virtual laminated body 1C, the thickness of each layer constituting the virtual laminated body 1C and the relationship between the stress and strain in each layer constituting the virtual laminated body 1C The wiring layer 12 of the virtual laminate 1C is obtained using the information on the distance H between the fixed plate 21 and the movable plate 22 in the bending test and the line width LW and the line width SW in the wiring layer 12 of the virtual laminate 1C. The bending life N of the virtual laminate 1C can be predicted based on the calculated stress and the stress-bending life relational expression. In the present embodiment, when the bending life N of the virtual laminated body 1C is predicted, it is not necessary to actually make the prototype of the laminated body 1. Moreover, in this Embodiment, the bending life N of the virtual laminated body 1C can be estimated by the calculation using each said information, without using a finite element method. Therefore, according to the present embodiment, it is possible to easily set the conditions of each layer constituting the multilayer body 1 and predict the bending life of the multilayer body 1. Thereby, according to this Embodiment, it becomes possible to obtain | require the preferable combination of the conditions of each layer which comprises the laminated body 1. FIG.

The present invention is not limited to the above-described embodiments, and various modifications can be made. For example, the laminated body to which the present invention is applied is not limited to the FPC in which the wiring layer is provided on only one surface of the base layer, but may be an FPC in which the wiring layer is provided on both surfaces of the base layer.

Based on the above description, it is apparent that various aspects and modifications of the present invention can be implemented. Therefore, the present invention can be implemented in forms other than the above-described best form within the scope equivalent to the following claims.

Claims

A fixed plate having a plurality of laminated layers including a base layer and a wiring layer made of a patterned conductor, extending in one direction, and being bendable and arranged at a predetermined interval; The laminated body is inserted in a U-shape between the movable plates, and the longitudinal ends of the laminated body are fixed to the fixed plate and the movable plate, respectively, and the movable plate is arranged in a direction parallel to the surface. A method for predicting a bending life to be measured by a bending test performed by reciprocating,
For each of the plurality of laminate samples having different configurations, the thickness of each layer constituting the sample, the relationship between the stress and strain in each layer constituting the sample, and the interval between the fixed plate and the movable plate in the bending test And a first calculation procedure for calculating a stress generated in the wiring layer of the sample using each information of the line width and the line width in the wiring layer of the sample,
For each of the plurality of samples, a procedure for measuring a bending life by the bending test,
Based on the stress generated in the wiring layer of each sample calculated by the first calculation procedure and the bending life of each sample measured by the procedure of measuring the bending life, The procedure for obtaining the relationship between the stress generated in the wiring layer and the flex life,
For the virtual laminate that is the object of predicting the flex life, the thickness of each layer constituting the virtual laminate, the relationship between the stress and strain in each layer constituting the virtual laminate, and the fixation in the flex test A second calculation procedure for calculating a stress generated in the wiring layer of the virtual laminate using the information on the distance between the plate and the movable plate, and the line width and the inter-line width in the wiring layer of the virtual laminate; ,
Based on the stress generated in the wiring layer of the virtual laminate calculated by the second calculation procedure and the relationship between the stress and the bending life obtained by the procedure for obtaining the relationship between the stress and the bending life. And a method for predicting the bending life of the virtual laminated body.
The method for predicting a flexural life of a laminate according to claim 1, wherein the elastic modulus of the material constituting each layer is used as the relationship between stress and strain in each layer.
2. The method for predicting the bending life of a laminate according to claim 1, wherein the relationship between stress and strain in each layer is obtained by a tensile test on the material constituting each layer.
In the first calculation procedure, as a stress generated in the wiring layer of the sample, a main stress obtained from a normal stress and a shear stress is calculated,
2. The bending of the laminate according to claim 1, wherein in the second calculation procedure, a principal stress obtained from a normal stress and a shear stress is calculated as the stress generated in the wiring layer of the virtual laminate. Life prediction method.
In the procedure for obtaining the relationship between the stress and the bending life, the temperature when the bending test is performed as a parameter, the relationship between the stress generated in the wiring layer and the bending life is obtained,
In the procedure of predicting the bending life, the virtual life under an arbitrary temperature is based on the stress calculated by the second calculation procedure and the relationship between the stress using the temperature as a parameter and the bending life. The bending life prediction method for a laminate according to claim 1, wherein the bending life of the laminate is predicted.
In the procedure for determining the relationship between the stress and the bending life, the frequency of the reciprocating motion of the movable plate in the bending test was used as a parameter to determine the relationship between the stress generated in the wiring layer and the bending life,
In the procedure for predicting the bending life, the virtual life under an arbitrary frequency is based on the stress calculated by the second calculation procedure and the relationship between the stress using the frequency as a parameter and the bending life. The bending life prediction method for a laminate according to claim 1, wherein the bending life of the laminate is predicted.
A fixed plate having a plurality of laminated layers including a base layer and a wiring layer made of a patterned conductor, extending in one direction, and being bendable and arranged at a predetermined interval; The laminated body is inserted in a U-shape between the movable plates, and the longitudinal ends of the laminated body are fixed to the fixed plate and the movable plate, respectively, and the movable plate is arranged in a direction parallel to the surface. A device for predicting a bending life to be measured by a bending test performed by reciprocating movement,
For each of the plurality of laminate samples having different configurations, the thickness of each layer constituting the sample, the relationship between the stress and strain in each layer constituting the sample, and the interval between the fixed plate and the movable plate in the bending test And first input means for inputting each information of the line width and the inter-line width in the wiring layer of the sample,
First calculation means for calculating stress generated in the wiring layer of the sample using information input by the first input means;
A second input means for inputting a bending life of each of the plurality of samples measured by the bending test;
Based on the stress generated in the wiring layer of each sample calculated by the first calculating means and the bending life of each sample input by the second input means, the wiring in the laminate of any configuration Means for determining the relationship between the stress generated in the layer and the bending life;
For the virtual laminate that is the object for predicting the flex life, the thickness of each layer constituting the virtual laminate, the relationship between the stress and strain in each layer constituting the virtual laminate, and the fixation in the flex test A third input means for inputting information on the distance between the plate and the movable plate, and the line width and the line width in the wiring layer of the virtual laminate;
Second calculation means for calculating the stress generated in the wiring layer of the virtual laminate using the information input by the third input means;
Based on the stress generated in the wiring layer of the virtual laminate calculated by the second calculating means, and the relationship between the stress and the bending life obtained by the means for obtaining the relationship between the stress and the bending life. And a means for predicting the bending life of the virtual laminated body.
The first calculation means calculates a principal stress obtained from a normal stress and a shear stress as a stress generated in the wiring layer of the sample,
The bending of the laminate according to claim 7, wherein the second calculation means calculates a principal stress obtained from a normal stress and a shear stress as the stress generated in the wiring layer of the virtual laminate. Life prediction device.
Means for obtaining the relationship between the stress and the bending life, the temperature when the bending test is performed as a parameter, the relationship between the stress generated in the wiring layer and the bending life,
The means for predicting the bending life is based on the stress calculated by the second calculating means and the relationship between the stress and the bending life with the temperature as a parameter and the virtual life under an arbitrary temperature. The bending life prediction device for a laminate according to claim 7, wherein the bending life of the laminate is predicted.
The means for determining the relationship between the stress and the bending life is to determine the relationship between the stress generated in the wiring layer and the bending life, using the frequency of the reciprocating motion of the movable plate in the bending test as a parameter.
The means for predicting the bending life is based on the stress calculated by the second calculating means and the relationship between the stress and the bending life with the frequency as a parameter and the virtual life under an arbitrary frequency. The bending life prediction apparatus for a laminated body according to claim 7, wherein the bending life of the laminated body is predicted.
A fixed plate having a plurality of laminated layers including a base layer and a wiring layer made of a patterned conductor, extending in one direction, and being bendable and arranged at a predetermined interval; The laminated body is inserted in a U-shape between the movable plates, and the longitudinal ends of the laminated body are fixed to the fixed plate and the movable plate, respectively, and the movable plate is arranged in a direction parallel to the surface. In order to predict the flexion life to be measured by a flex test performed with reciprocating motion,
For each of the plurality of laminate samples having different configurations, the thickness of each layer constituting the sample, the relationship between the stress and strain in each layer constituting the sample, and the interval between the fixed plate and the movable plate in the bending test And a first input means for inputting information on the line width and the inter-line width in the wiring layer of the sample,
First calculation means for calculating a stress generated in the wiring layer of the sample, using information input by the first input means;
A second input means for inputting a bending life of each of the plurality of samples measured by the bending test;
Based on the stress generated in the wiring layer of each sample calculated by the first calculating means and the bending life of each sample input by the second input means, the wiring in the laminate of any configuration Means for determining the relationship between the stress generated in the layer and the flex life,
For the virtual laminate that is the object for predicting the flex life, the thickness of each layer constituting the virtual laminate, the relationship between the stress and strain in each layer constituting the virtual laminate, and the fixation in the flex test A third input means for inputting information on the distance between the plate and the movable plate, and the line width and the line width in the wiring layer of the virtual laminate;
Second calculation means for calculating a stress generated in the wiring layer of the virtual laminate using the information input by the third input means; and the virtual laminate calculated by the second calculation means. Means for predicting the bending life of the virtual laminate based on the stress generated in the wiring layer of the body and the relationship between the stress and the bending life determined by the means for determining the relationship between the stress and the bending life;
Flex life prediction program for laminates to function as
A computer-readable recording medium in which a bending life prediction program for a laminate is recorded,
The program has a plurality of laminated layers including a base layer and a wiring layer made of a patterned conductor, and is arranged at a predetermined interval with respect to a laminate that extends in one direction and can be bent. The laminated body is bent in a U shape between the fixed plate and the movable plate, and each end in the longitudinal direction of the laminated body is fixed to the fixed plate and the movable plate, and the movable plate is placed on the surface. In order to predict the bending life to be measured by a bending test performed by reciprocating in parallel directions,
For each of the plurality of laminate samples having different configurations, the thickness of each layer constituting the sample, the relationship between the stress and strain in each layer constituting the sample, and the interval between the fixed plate and the movable plate in the bending test And a first input means for inputting information on the line width and the inter-line width in the wiring layer of the sample,
First calculation means for calculating a stress generated in the wiring layer of the sample, using information input by the first input means;
A second input means for inputting a bending life of each of the plurality of samples measured by the bending test;
Based on the stress generated in the wiring layer of each sample calculated by the first calculating means and the bending life of each sample input by the second input means, the wiring in the laminate of any configuration Means for determining the relationship between the stress generated in the layer and the flex life,
For the virtual laminate that is the object for predicting the flex life, the thickness of each layer constituting the virtual laminate, the relationship between the stress and strain in each layer constituting the virtual laminate, and the fixation in the flex test A third input means for inputting information on the distance between the plate and the movable plate, and the line width and the line width in the wiring layer of the virtual laminate;
Second calculation means for calculating a stress generated in the wiring layer of the virtual laminate using the information input by the third input means; and the virtual laminate calculated by the second calculation means. Means for predicting the bending life of the virtual laminate based on the stress generated in the wiring layer of the body and the relationship between the stress and the bending life determined by the means for determining the relationship between the stress and the bending life;
A recording medium characterized by functioning as a recording medium.