KR20100138889A - 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 - Google Patents

Abstract

In the method for predicting the bending life of a laminate having a plurality of layers, the thickness of each layer constituting the virtual laminate and the stress and strain in each layer constituting the virtual laminate are measured. The stress generated in the wiring layer in the virtual laminate is calculated using the relationship, the distance between the fixed plate and the movable plate in the bending test, and the line width and the line width in the wiring layer of the virtual laminate. Then, the bending life of the virtual laminate is predicted based on the calculated stress and the relationship between the stress and the bending life.

Description

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}

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

Background Art In recent years, flexible printed wiring boards (hereinafter referred to as FPCs) have been widely used in electronic devices having movable parts, such as mobile phones, hard disk devices, and printers. This FPC has a base layer, the wiring layer which consists of a patterned conductor joined to one surface of this base layer, the adhesive layer which covers this wiring layer, and the cover layer bonded to this adhesive layer, for example.

The high flex resistance property is required for the FPC used in the electronic apparatus which has a movable part. One of the tests for evaluating the bending resistance characteristics of the FPC is a bending test called the IPC test. In this bending test, the FPC is bent into a U-shape between a fixed plate and a movable plate arranged at predetermined intervals, and each end of the FPC in the longitudinal direction is fixed to the fixed plate and the movable plate, respectively. This is done by reciprocating in a direction parallel to the plane. 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 is broken is measured as the bending life.

However, if the FPC is to be designed to meet the desired bending resistance characteristics, it is enormously labor, time and cost to repeat the FPC test production and bending test. Thus, if the flex life of the FPC can be predicted by simulation, it becomes possible to reduce labor, time and cost.

Conventionally, regarding the flexible wiring member like FPC, as a method of predicting the bending resistance characteristics, such as a bending life, by simulation, it divided largely, and there existed the following 1st and 2nd methods. For example, as described in Patent Literature 1, the first method is a method using a measured value of a master curve and a prediction target. The second method is a method using a finite element method, for example, as described in Patent Document 2 or Patent Document 3.

Patent Document 1 describes a method of predicting the bending life of a composite such as a flat cable. In this method, first, the master curve which shows the relationship between the maximum deformation amount of the conductor part of a composite body, and / or the deviation amount from the abnormal radius of a curved shape when it is attached to a bending resistance evaluation test apparatus, and the measured bending life is created. . Next, the maximum amount of deformation of the conductor portion and / or the amount of deviation from the abnormal radius of the bent shape in the composite to be predicted mounted on the bending resistance evaluation test apparatus is measured. Next, the measured maximum deformation amount of the conductor portion and / or the deviation amount from the abnormal radius of the bent shape in the composite to be predicted is compared with the master curve to predict the bending life of the composite to be predicted.

Patent Document 2 describes a method of predicting the bending life of an electric wire or an electric wire bundle having at least a center conductor line. In this method, first, a master curve showing the relationship between the bending life of a single wire and the amount of deformation change is obtained. Next, the maximum deformation change of the center conductor line of the wire or bundle of wires to be predicted is calculated using the finite element method. Next, the calculated maximum deformation change amount is compared with the master curve to predict the bending life of the wire or bundle of wires to be predicted.

Patent Document 3 describes a method of predicting flexural durability of a plurality of electric wires and a flexural protection member attached to the flexion portion. In this method, first, each finite element model of a plurality of electric wires and a bend protection member is created. Next, the stress in each finite element of the finite element model is calculated. Next, the maximum stress among the calculated stresses is retrieved. Next, with reference to the prediction function, each bending endurance number corresponding to the maximum stress for each of the plurality of electric wires and the bending protection member is obtained, and the shortest bending endurance number is obtained therefrom.

Japanese Patent Application Laid-Open No. 8-166333 Japanese Patent Application Laid-Open No. 2002-260459 Japanese Patent Application Laid-Open No. 2004-191361

(Initiation of invention)

(Tasks to be solved by the invention)

By the way, in the flexible laminate which has several layers like FPC, many structures can be considered by changing the conditions of several layers. For each of these many configurations, repeating the trial fabrication and flexural tests requires enormous labor, time, and money. Therefore, in order to design a laminate having a desired bending life, it is possible to drastically reduce labor, time, and cost, if the simulation of predicting the bending life is possible by arbitrarily setting the conditions of each layer constituting the laminate. Done. In addition, if such a simulation is possible, it is also possible to easily obtain a preferable combination of the conditions of each layer constituting the laminate.

However, since the first method of the conventional method of predicting bending resistance such as bending life by simulation uses the actual measurement value of the prediction object, the simulation can be performed by arbitrarily setting the conditions of each layer constituting the laminate. There is a problem that no. Moreover, in a 1st method, a preferable combination of the conditions of each layer which comprises a laminated body cannot also be calculated | required using simulation.

In addition, since the finite element method is used in the first method of the conventional method of predicting the bending resistance characteristics such as the bending life by simulation, there is a problem that a lot of time and labor are required to prepare the finite element model.

An object of the present invention is to easily set the conditions of each layer constituting the laminate, and to predict the bending life of the laminate, the bending life prediction method of the laminate, the bending life prediction apparatus of the laminate, and the laminate It is to provide a bending life prediction program and recording medium of the sieve.

The bending life prediction method of the laminate of the present invention has a plurality of laminated layers including a base layer and a wiring layer made of a patterned conductor, and extends in one direction and are arranged at predetermined intervals with respect to the bendable laminate. The laminate is bent into a U-shape between the fixed plate and the movable plate, and each end in the longitudinal direction of the laminate is fixed to the fixed plate and the movable plate, respectively, and the movable plate is reciprocated in a direction parallel to the plane thereof. It is a method of predicting the bending life measured by the bending test performed.

The bending life prediction method of the laminate of the present invention,

For each of the samples of a plurality of laminates having different configurations, the thickness of each layer constituting the sample, the relationship between stress and strain in each layer constituting the sample, the fixed plate and the movable plate in the bending test. A first calculation procedure for calculating the stress generated in the wiring layer of the sample by using the information on the interval between the lines and the line width and the line width in the wiring layer of the sample;

A procedure for measuring a bending life by a bending test for each of a plurality of samples;

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 for measuring the bending life, the wiring layer in the laminate of any configuration The procedure for calculating the relationship between stress and bending life,

For the virtual laminate which is the object of predicting the bending life, the thickness of each layer constituting the virtual laminate, the relationship between stress and strain in each layer constituting the virtual laminate, and the bending test A second calculation procedure for calculating stress generated in the wiring layer of the virtual laminate using information of the interval between the fixed plate and the movable plate, and the line width and the line width in the wiring layer of the virtual laminate;

The curvature of the virtual laminated body based on the relationship between the stress which generate | occur | produces in the wiring layer of the virtual laminated body computed by the 2nd calculation procedure, and the stress and bending life calculated by the procedure which calculates the relationship between a stress and a bending lifespan. It has a procedure for predicting the life.

In the bending life prediction method of the laminated body of this invention, you may use the elasticity modulus of the material which comprises each layer as a relationship of the stress and deformation in each layer.

Moreover, in the bending life prediction method of the laminated body of this invention, the relationship of the stress and strain in each layer may be acquired by the tension test regarding the material which comprises each layer.

Moreover, in the bending life prediction method of the laminated body of this invention, in the 1st calculation procedure, the main stress calculated | required from a perpendicular stress and a shear stress is calculated as a stress which arises in the wiring layer of a sample, and in a 2nd calculation procedure, The main stress obtained from the vertical stress and the shear stress may be calculated as the stress generated in the wiring layer of the laminate.

In the method for predicting the bending life of the laminate according to the present invention, in the procedure for obtaining the relationship between the stress and the bending life, the relationship between the stress and the bending life generated in the wiring layer with the temperature at the time of the bending test as a parameter is determined. In the procedure for calculating and predicting the bending life, the bending life of the virtual laminate under an arbitrary temperature is predicted based on the relationship between the stress calculated by the second calculation procedure, the stress whose temperature is a parameter, and the bending life. You may also

Moreover, in the bending life prediction method of the laminated body of this invention, in the procedure which calculates the relationship between a stress and a bending life, the stress and the bending which generate | occur | produce in the wiring layer which made the frequency of the reciprocating motion of the movable plate in a bending test the parameter. In the procedure for obtaining the relationship with the life and predicting the bending life, the virtual laminate under an arbitrary frequency based on the relationship between the stress calculated by the second calculation procedure, the stress with the frequency as the parameter, and the bending life. The bending life of may be predicted.

The bending life prediction apparatus of the 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, and extends in one direction and is arranged at predetermined intervals with respect to the bendable laminate. The laminate is bent into a U-shape between the fixed plate and the movable plate, and each end in the longitudinal direction of the laminate is fixed to the fixed plate and the movable plate, respectively, and the movable plate is reciprocated in a direction parallel to the plane thereof. It is an apparatus which predicts the bending life measured by the bending test performed.

The bending life predicting device of the laminate of the present invention,

For each of the samples of a plurality of laminates having different configurations, the thickness of each layer constituting the sample, the relationship between stress and strain in each layer constituting the sample, the fixed plate and the movable plate in the bending test. First input means for inputting respective pieces of information about the interval between the lines and the line width and line width in the wiring layer of the sample;

First calculation means for calculating the stress generated in the wiring layer of the sample using the information input by the first input means,

Second input means for inputting each bending life of the plurality of samples measured by the bending test;

The stress generated in the wiring layer in the laminate of any configuration based on the stress generated in the wiring layer of each sample calculated by the first calculating means, the bending life of each sample input by the second input means, Means for obtaining a relationship with flex life,

For the virtual laminate which is the object of predicting the bending life, the thickness of each layer constituting the virtual laminate, the relationship between stress and strain in each layer constituting the virtual laminate, and the bending test Third input means for inputting respective information of the line width and the line width in the wiring layer of the virtual laminate, and the space between the fixed plate and the movable plate;

Second calculation means for calculating a stress generated in the wiring layer of the virtual laminate using information input by the third input means,

Flexural life of the virtual laminate based on the relationship between the stress generated in the wiring layer of the virtual laminate calculated by the second calculation means and the relationship between the stress and the bending life calculated by the means for calculating the relationship between the stress and the bending life. It has a means for predicting.

In the bending life predicting apparatus of the laminate of the present invention, the first calculating means calculates a main stress obtained from the vertical stress and the shear stress as stress generated in the wiring layer of the sample, and the second calculating means is a virtual lamination. As a stress which generate | occur | produces in the wiring layer of a sieve, you may calculate main stress calculated | required from a normal stress and a shear stress.

Moreover, in the bending life prediction apparatus of the laminated body of this invention, the means which calculates the relationship between a stress and a bending life is a relationship between the stress and the bending life which generate | occur | produce in a wiring layer which made the temperature at the time of a bending test a parameter. The means for predicting the bending life is calculated based on the relationship between the stress calculated by the second calculating means, the stress whose temperature is a parameter, and the bending life, and the bending life of the virtual laminate under an arbitrary temperature. You may predict.

Moreover, in the bending life prediction apparatus of the laminated body of this invention, the means which calculates the relationship between a stress and a bending life consists of the stress which generate | occur | produces in the wiring layer which made the frequency of the reciprocating motion of the movable plate in a bending test the parameter, The means for calculating the relationship with the bending life and for predicting the bending life is based on the relationship between the stress calculated by the second calculation means, the stress whose frequency is the parameter, and the bending life, under an arbitrary frequency. The bending life of may be predicted.

The bending life prediction program of the laminate of the present invention has a plurality of laminated layers including a base layer and a wiring layer composed of a patterned conductor, and extends in one direction and is arranged at predetermined intervals with respect to the bendable laminate. The laminate is bent into a U-shape between the fixed plate and the movable plate, and each end in the longitudinal direction of the laminate is fixed to the fixed plate and the movable plate, respectively, and the movable plate is reciprocated in a direction parallel to the plane thereof. It is a program for making a computer function as each of the following means, in order to predict the bending life measured by the bending test performed.

The bending life prediction program of the laminate of the present invention is a computer,

For each of the samples of a plurality of laminates having different configurations, the thickness of each layer constituting the sample, the relationship between stress and strain in each layer constituting the sample, the fixed plate and the movable plate in the bending test. First input means for inputting respective pieces of information of the line width and the 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 the information input by the first input means,

Second input means for inputting each bending life of the plurality of samples measured by the bending test,

The stress generated in the wiring layer in the laminate of any configuration based on the stress generated in the wiring layer of each sample calculated by the first calculating means, the bending life of each sample input by the second input means, Means for obtaining a relationship with flex life,

For the virtual laminate which is the object of predicting the bending life, the thickness of each layer constituting the virtual laminate, the relationship between stress and strain in each layer constituting the virtual laminate, and the bending test Third input means for inputting each piece of information of the line width and the line width in the wiring layer of the virtual laminate and the space between the fixed plate and the movable plate;

Second calculation means for calculating stress generated in the wiring layer of the virtual laminate using information input by the third input means, and

Flexural life of the virtual laminate based on the relationship between the stress generated in the wiring layer of the virtual laminate calculated by the second calculation means and the relationship between the stress and the bending life calculated by the means for calculating the relationship between the stress and the bending life. Function as a means for predicting

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

According to the bending life prediction method of the laminate, the bending life prediction apparatus of the laminate, the bending life prediction program of the laminate or the recording medium, the thickness of each layer constituting the virtual laminate for the virtual laminate. And information on the relationship between stress and strain in each layer constituting the virtual laminate, the interval between the fixed plate and the movable plate in the bending test, and the line width and 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 to predict the bending life of the virtual laminate based on the calculated stress and the relationship between the stress and the bending life. Thereby, according to this invention, it becomes possible to easily set the conditions of each layer which comprises a laminated body easily, and to predict the bending life of a laminated body.

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

BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view which shows a part of laminated body in 1 Embodiment of this invention.
It is a top view which shows the wiring layer of the laminated body in 1 Embodiment of this invention.
3 is an explanatory view showing a state in which a laminate is mounted on a bending test apparatus used for a bending test.
4 is a block diagram showing the configuration of a computer for realizing a bending life predicting apparatus according to an embodiment of the present invention.
Fig. 5 is a functional block diagram showing the functional configuration of the bending life predicting apparatus according to the embodiment of the present invention.
6 is a flowchart showing a bending life prediction method of a laminate according to one embodiment of the present 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. 8 is a characteristic diagram showing the relationship between the principal stress and the bending life expressed by the stress-flex life lifetime equation in one embodiment of the present invention.

Best Mode for Carrying Out the Invention [

Hereinafter, the bending life prediction method of a laminate, the bending life prediction apparatus of a laminate, the bending life prediction program of 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 laminate in the present embodiment has a plurality of stacked layers including a base layer and a wiring layer made of a patterned conductor, and extends in one direction and is 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. 1 is a perspective view showing a part of a laminate. In FIG. 1, the hatched surface has shown the cross section. 2 is a plan view showing a wiring layer of a laminate. The laminate shown in Figs. 1 and 2 is specifically FPC. However, this FPC is a test FPC used for measuring the bending life by the bending test.

As shown in FIG. 1, the laminated body 1 consists of the base layer 11, the wiring layer 12 which consists of the patterned conductor joined to one surface of this base layer 11, and this wiring layer 12 ) And a cover layer 14 bonded to the adhesive layer 13. Moreover, the laminated body 1 extends in one direction and can be bent. In addition, the laminate 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 a plurality of linear portions 12a extending in the longitudinal direction (left and right direction in FIG. 2) of the laminate 1, and the entire wiring layer 12 is meander shaped. It has a connecting part 12b which connects the edge parts of two adjacent linear parts 12a so that it may become. Here, the width (dimensions in the vertical direction in FIG. 2) of the linear portion 12a is defined as the line width LW, and the interval between two adjacent linear portions 12a is defined as the line width SW. define.

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

In addition, in the following description, the terms "sample of a laminated body", "the laminated body of arbitrary structure", and "virtual laminated body" are used with respect to the laminated body 1. As shown in FIG. The "sample of laminated body" is a laminated body actually produced in order to create a stress-flex life relationship equation as a relationship between stress and bending life occurring in the wiring layer 12 in the laminate having any configuration described below ( 1). "Laminated body of arbitrary structure" is an imaginary laminated body 1 in which conditions other than the minimum requirements of the laminated body 1 are not specified. "Virtual laminated body" is the imaginary laminated body 1 which is an object which predicts a bending life. "Virtual laminated body" is the thickness of each layer which comprises the laminated body 1, the relationship of the stress and strain in each layer which comprises the laminated body 1, and the fixed board and movable board in a bending test. The distance between the lines and the line width LW and the line width SW in the wiring layer 12 of the laminate 1 are specified. Hereinafter, in order to distinguish a "sample of a laminated body", "a laminated body of arbitrary structure", and a "virtual laminated body", the code | symbol 1A is attached | subjected to the "sample of a laminated body", and to the "laminate body of arbitrary structure" The code | symbol 1B is attached | subjected and the code | symbol 1C is attached | subjected to a "virtual laminated body."

Next, with reference to FIG. 3, the bending test for measuring the bending life of the laminated body 1 is demonstrated. 3 is an explanatory diagram 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 arranged at predetermined intervals H. In the bending test, the laminate 1 is bent into a U-shape between the stationary plate 21 and the movable plate 22, and the end portions in the longitudinal direction of the laminate 1 are fastened to the fixtures 23 and 24, respectively. The fixing plate 21 and the movable plate 22 are fixed to each other, 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. And when the resistance value of the wiring layer 12 becomes more than predetermined value, it is judged that the wiring layer 12 broke. 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, i.e., until the resistance value of the wiring layer 12 becomes equal to or more than a predetermined value is the life of the bending. Is measured.

Next, with reference to FIG. 4 and FIG. 5, the bending life predicting apparatus which concerns on this embodiment is demonstrated. The bending life prediction apparatus 30 which concerns on this embodiment is an apparatus which predicts the bending life measured by the above-mentioned bending test with respect to the laminated body 1. As shown in FIG. The bending life predicting device 30 is realized using a computer.

4 is a block diagram showing the configuration of a computer 30C which realizes the bending life predicting device 30. As shown in FIG. 4, the computer 30C includes a main controller 31, an input device 32, an output device 33, a display device 34, a storage device 33, and these. A bus 36 is connected to each other. The main controller 31 has a CPU (central processing unit), a ROM (lead only memory) and a RAM (random access memory). The storage device 33 may be any type as long as it can store information. For example, the storage device 33 is a hard disk device or an optical disk device. The storage device 33 also records information on the computer-readable recording medium 37 and reproduces the information from the recording medium 37. The recording medium 37 may be any type, as long as it can store information. For example, the recording medium 37 is a hard disk or an optical disk. The recording medium 37 may be a recording medium on which the bending life prediction program of the laminate according to the present embodiment is recorded.

5 is a functional block diagram illustrating a functional configuration of the bending life predicting device 30. As shown in FIG. 5, the bending life predicting device 30 includes a first input means 41, a first calculation means 42, a second input means 43, and a stress-flex life relationship creation means. 44, the third input means 45, the second calculation means 46, and the bending life predicting means 47 are provided.

The first input means 41 has a thickness of each layer constituting the sample 1A and each layer constituting the sample 1A with respect to each of the samples 1A of the plurality of laminates having different configurations. Relationship between stress and strain, the gap H between the fixed plate 21 and the movable plate 22 in the bending test, the line width LW and the line width (in the wiring layer 12 of the sample 1A) Enter each information of SW). The 1st calculating means 42 calculates the stress which arises in the wiring layer 12 of the sample 1A using the information input by the 1st input means 41. FIG. The second input means 43 inputs the bending life of each of the plurality of samples 1A measured by the bending test.

The stress-flexion life relationship creation means 44 includes the stress generated in the wiring layer 12 of each sample 1A calculated by the first calculation means 42 and the input by the second input means 43. Based on the bending life of each sample 1A, the relationship between the stress generated in the wiring layer 12 and the bending life in the laminate 1B of any configuration is obtained. Specifically, the stress-bending life relationship creation means 44 is a relationship between the stress generated in the wiring layer 12 in the laminate 1B of any configuration and the bending life, and expresses the stress-bending life relationship. Write. The stress-flexion life relationship creation means 44 corresponds to "means for obtaining the relationship between stress and bending life" in the present invention.

The 3rd input means 45 has the thickness of each layer which comprises the virtual laminated body 1C, and the each layer which comprises the virtual laminated body 1C with respect to the virtual laminated body 1C. Relationship between stress and deformation, gap H between the fixed plate 21 and the movable plate 22 in the bending test, the line width LW and the line width in the wiring layer 12 of the virtual laminate 1C. Input the information of the width SW. The 2nd calculating means 46 calculates the stress which generate | occur | produces in the wiring layer 12 of the virtual laminated body 1C using the information input by the 3rd input means 45. FIG.

The bending life predicting means 47 uses the stress generated in the wiring layer 12 of the virtual laminate 1C calculated by the second calculating means 46 and the stress-flexing life relationship formula generating means 44. Based on the created stress-flex life equation, the bending life of the virtual laminate 1C is predicted.

The bending life prediction program of the laminate according to the present embodiment shows the computer 30C shown in FIG. 4 in FIG. 5 in order to predict the bending life measured by the above-described bending test for the laminate 1. It is to function as one means. The bending life prediction program of this laminate is recorded in a ROM in the recording medium 37 or main controller 31 in FIG.

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

6 is a flowchart showing the bending life prediction method of the laminate according to the present embodiment. As shown in FIG. 6, in the bending life prediction method of the laminated body which concerns on this embodiment, first, each which comprises the sample 1A with respect to each of the sample 1A of the several laminated body of different structure is provided. The thickness of the layer, the relationship between stress and strain in each layer constituting the sample 1A, the interval H between the fixed plate 21 and the movable plate 22 in the bending test, and the sample 1A. The stress generated in the wiring layer 12 of the sample 1A is calculated using the respective information of the line width LW and the line width SW in the wiring layer 12 (step 101). This step S101 corresponds to the first calculation procedure in the present invention. Next, for each of the plurality of samples 1A, the bending life is measured by the bending test (step S102).

Next, the laminated body 1B of arbitrary structures based on the stress which arises in the wiring layer 12 of each sample 1A calculated by step S101, and the bending life of each sample 1A measured by step S101. As a relationship between the stress generated in the wiring layer 12 and the bending life in Fig. 2), a stress-bending life relationship equation is obtained (step S103).

Next, with respect to the virtual laminated body 1C, the thickness of each layer which comprises the virtual laminated body 1C, the relationship of the stress and strain in each layer which comprises the virtual laminated body 1C, Information of the line width LW and the line width SW in the wiring layer 12 of the virtual laminate 1C and the space H between the fixed plate 21 and the movable plate 22 in the bending test. The stress which generate | occur | produces in the wiring layer 12 of 1 C of virtual laminated bodies is computed using (Step S104). This step S104 corresponds to the second calculation procedure in the present invention.

Next, based on the stress which generate | occur | produces in the wiring layer 12 of the virtual laminated body 1C computed by step S10, and the stress and bending life calculated by step S103, The bending life is predicted (step S105).

Each step (step) described above predicts the bending life of the virtual laminate 1C. In addition, the procedure of step S101 and step S102 may be reversed from the above description.

Next, the operation of the bending life predicting device 30 in the case where the bending life predicting device 30 according to the present embodiment realizes the above-described bending life predicting method of the laminate will be described. In step S101, the thickness of each layer which comprises the sample 1A with respect to each of the sample 1A of the several laminated body 1 of a different structure by the 1st input means 41 first, The relationship between stress and strain in each layer constituting the sample 1A, the gap H between the fixed plate 21 and the movable plate 22 in the bending test, and the wiring layer 12 of the sample 1A. Each piece of information about the line width LW and the line width SW is input. Next, using the information input by the 1st input means 41, the 1st calculation means 42 calculates the stress which arises in the wiring layer 12 of the sample 1A.

In step S102, the 2nd input means 43 inputs the bending life of each of several sample 1A measured by the bending test.

In step S103, the stress which arises in the wiring layer 12 of each sample 1A calculated by the 1st calculating means 42, and the bending life of each sample 1A input by the 2nd input means 43 are shown. Based on the stress-bending life relationship creation means 44, the stress-bending life relationship equation as a relationship between the stress generated in the wiring layer 12 in the laminate 1B of any configuration and the bending life. Write.

In step S104, the third input unit 45 configures the thickness of each layer constituting the virtual laminate 1C and the virtual laminate 1C with respect to the virtual laminate 1C. Relationship between stress and strain in each layer, the interval H between the fixed plate 21 and the movable plate 22 in the bending test, and the line width in the wiring layer 12 of the virtual laminate 1C. And input each piece of line width. Next, using the information input by the 3rd input means 45, the 2nd calculating means 46 calculates the stress which arises in the wiring layer 12 of the virtual laminated body 1C.

In step S105, the stress which generate | occur | produces in the wiring layer 12 of the virtual laminated body 1C computed by the 2nd calculation means 46, and the stress-flexion life created by the stress-flexion life relationship formula creation means 44. The bending life predicting means 47 predicts the bending life of the virtual laminate 1C based on the relational expression.

Hereinafter, the bending life prediction method of the laminated body which concerns on this embodiment is demonstrated in detail. First, the calculation method of the stress which generate | occur | produces in the wiring layer 12 in step S101 and step S104 is demonstrated in detail with reference to FIG. 7 is a cross-sectional view of a model of the laminate 1 used for explaining the stress calculation method. In FIG. 7, the model of which the laminated body 1 is three layers is used for convenience, The following description is suitable for the first half when a laminated body is two or more layers. Here, the number of layers of the laminate 1 is n (n is an integer of 2 or more). Moreover, the i-th (i = 1, 2, ... n) layer which is counted from the bottom among each layer which comprises this laminated body 1 is called an i-th layer. In FIG. 7, the code | symbol B has shown the width | variety of the laminated body 1. As shown in FIG. In addition, the width here is a dimension of the direction parallel to the lower surface of the 1st layer, and perpendicular | vertical to the longitudinal direction of the laminated body 1.

In addition, in the laminated body 1 in this embodiment, since the wiring layer 12 is patterned as shown, for example in FIG. 2, when the laminated body 1 is seen from above, the laminated body 1 is carried out. There are a portion where the wiring layer 12 exists and a portion where the wiring layer 12 does not exist. Here, the part in which the wiring layer 12 exists is called a wiring part, and the part in which the wiring layer 12 does not exist is called a space part. In the wiring section and the space section, the configuration is different. For example, in the laminated body 1 shown in FIG. 1, a wiring part is comprised by four layers and a space part is comprised by three layers. Therefore, the wiring part and the space part are considered as follows below as needed.

[Calculation of neutral plane position]

Here, the lower surface of the first layer is referred to as the reference plane SP. Hereinafter, the case where the laminated body 1 is bent so that a reference surface SP may become convex at the lower side in FIG. 7 is considered. In FIG. 7, the code | symbol NP has shown the neutral plane of the laminated body 1. As shown in FIG. Here, the distance between the neutral plane NP and the reference plane SP is made into the neutral plane position NP, and this neutral plane position NP is calculated by the wiring section and the space section, respectively. The neutral plane position [NP] is calculated by the following equation (1).

Here, E _i is the elastic modulus of the material constituting the i-th layer. This elastic modulus E _i corresponds to the "relationship 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. 7. When the neutral plane position [NP] of the wiring portion is obtained, the value of the line width LW is used as B _i , and when the neutral plane position [NP] of the space portion is obtained, the value of the line width SW is used as B _i . use. h _i is the distance between the center plane of the i-th layer and the reference plane SP. In addition, the center surface of the i-th layer is an imaginary surface located in the center of the thickness direction of an i-th layer. t _i is the thickness of the i th layer. The symbol "Σ _{i = 1} ⁿ " represents the sum of i from 1 to n. Hereinafter, the neutral plane position of a wiring part is described as [NP] _Line .

[Calculation of the effective radius of curvature]

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

[Calculation of Bending Vertical Stress]

Next, the bending vertical stress? C which is the maximum tensile vertical stress in the longitudinal direction generated in the wiring layer 12 by the net bending is calculated. The bending vertical stress sigma c is calculated by the following equation (3).

Here, Ec is the elastic modulus of the wiring layer 12. yc is the distance from the reference surface SP to the surface (here lower surface) which becomes convex at the time of bending among the upper surface and lower surface of the wiring layer 12.

[Calculation of equivalent bending stiffness]

Next, the equivalent bending stiffness [BR] which is the bending stiffness of the whole laminated body 1 is calculated. The equivalent bending stiffness [BR] is calculated by the following equation (4).

Here, B _Line is the total of the line width (LW), B _Space is the total of the line width (SW). 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 and the neutral plane NP of the i-th layer. {Σ _{i = 1} ⁿ E _i (a _i ³ -b _i ³ ) / 3} _Line is the value of E _i (a _i ³ -b _i ³ ) / 3 in the wiring section, i is from 1 to n Is the total of. {Σ _{i = 1} ⁿ E _i (a _i ³ -b _i ³ ) / 3} _Space is the sum of 1 to n of values of E _i (a _i ³ -b _i ³ ) / 3 in the space section. to be. Also related to equation (4), with respect to the i-th layer, B _i (a _i ³ -b _i ³ ) / 3 is a parameter representing the geometrical characteristics of the cross section, commonly referred to as the cross section secondary moment. The value obtained by multiplying the cross-sectional secondary 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 laminated body 1 is calculated. The bending moment M is calculated by the following equation (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).

Where k is the shear modulus. When the effective radius of curvature R at the bending test is about 1 mm, a value of 5/6, which is generally used as the first shear modulus, is used as the value of k. Le is half of the perimeter of the effective bend. A is the area of the cross section of the laminate 1 perpendicular to the longitudinal direction of the laminate 1.

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

In this way, the main stress S as a stress which arises in the wiring layer 12 from the normal stress (sigma) c and the shear stress (tau) is calculated. In addition, this main stress S is the relationship between the thickness of each layer which comprises the laminated body 1, and the stress and strain in each layer which comprises the laminated body 1 (elasticity) as above-mentioned. And the information about the interval 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.

In step S101, the principal stress S which arises in the wiring layer 12 is computed with respect to each of the sample 1A of the several laminated body of a different structure by the said method. In step S104, the principal stress S which generate | occur | produces in the wiring layer 12 is computed with respect to the virtual laminated body 1C which is an object which predicts a bending life.

In step S102, the bending life time N is measured with respect to each of the some sample 1A by the bending test demonstrated with reference to FIG. The frequency of the reciprocating motion of the movable plate 22 in this bending test is called f. In addition, the temperature at the time of a bending test is called T. The bending test may be carried out with the frequency f and the temperature T constant for all the samples 1A, or at least one of the frequency f and the temperature T may be different for each of the samples 1A. . Alternatively, a plurality of types of samples 1A are produced in plural numbers for one kind, and at least one of the frequency f and the temperature T is different for each of the plurality of types of samples 1A. The bending test may be performed. When at least one of the frequency f and the temperature T is differently subjected to the bending test with respect to the plurality of samples 1A, the stress-flexion life relation formula created in step S103 is obtained by the frequency f and the temperature. It becomes possible to set it as a function which made at least one of (T) a parameter.

Next, in Step S103, a method for obtaining the stress-bending life relationship equation as a relationship between the stress generated in the wiring layer 12 in the laminate 1B having any configuration and the bending life will be described. As a result of obtaining the main stresses S and the bending lifespan generated in the wiring layer 12 with respect to the plurality of samples 1A, the main stresses S generated in the wiring layer 12 with respect to the laminated body 1B of an arbitrary configuration. It was found that the relationship between and the bending life (N) can be approximated by the following equation (8). Therefore, in the present embodiment, the following equation (8) is used for stress-meaning the relationship between the main stress S and the bending life N generated in the wiring layer 12 in the laminated body 1B of any configuration. It is called the bending life relationship. The relationship between the principal stress S and the bending lifespan N represented by Formula (8) is as shown in FIG. 8 when it shows in drawing.

Here, α, β, χ and δ are property parameters (integers). In step S103, the expression (8) is a formula for approximating the data of the principal stress S and the bending life span N generated in the wiring layer 12 with respect to the plurality of samples 1A by the least square method. Determine the values of β, χ, and δ. Thereby, Formula (8) becomes an expression which shows the relationship between the main stress S and the bending lifetime N with respect to the laminated body 1B of arbitrary structures.

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

In a case where a bending test is performed on a plurality of samples 1A with the frequency f and the temperature T as constant values, respectively, and equation (8) is prepared using the data obtained by the bending test, equation (8) is used. Is a formula representing the relationship between the principal stress S and the bending lifespan N when the bending test is performed under the condition that the frequency f and the temperature T are the above constant values. In this case, using the formula (8), the bending life in the case where the bending test is performed on the virtual laminate 1C under the condition that the frequency f and the temperature T are the above constant values, respectively ( N) can be predicted.

When the frequency f is set to a constant value, the temperature T is changed to perform a bending test on the plurality of samples 1A, and the equation (8) is prepared using the data obtained by the bending test. 8) is a formula showing the relationship between the principal stress S and the bending life N in which the temperature T is a parameter when the bending test is performed under the condition that the frequency f is the above constant value. do. In this case, using the formula (8), the bending in the case where the bending test is performed on the virtual laminate 1C under the condition that the frequency f is the above constant value under an arbitrary temperature T. It is possible to predict the lifetime (N).

When the temperature T is set to a constant value and the frequency f is changed to perform a bending test on a plurality of samples 1A, and equation (8) is prepared using the data obtained by the bending test, the equation (8) is used. 8) is a formula showing the relationship between the principal stress S and the bending life N in which the frequency f is a parameter when the bending test is performed under the condition that the temperature T is the above constant value. . In this case, the bending in the case where the bending test is performed on the virtual laminate 1C under the condition that the temperature T is the above constant value under an arbitrary frequency f using the formula (8). It is possible to predict the lifetime (N).

When both the frequency f and the temperature T are changed to perform a bending test on a plurality of samples 1A, and equation (8) is prepared using the data obtained by the bending test, equation (8) is It becomes an expression which shows the relationship between the main stress S and the bending life | span N which used the frequency f and the temperature T as parameters. In this case, using the formula (8), the bending life span (N) in the case where the bending test is performed on the virtual laminate 1C at an arbitrary temperature (T) and at an arbitrary frequency (f) is performed. It becomes possible to predict.

In addition, in description using Formula (1)-(7), although the elasticity modulus of the material which comprises each layer was used as a relationship of the stress and deformation in each layer which comprises the laminated body 1, the laminated body 1 The relationship between the stress and the strain in each layer constituting) may be obtained by a tensile test on the material constituting each layer. What may be acquired by the tension test with respect to the material which comprises each layer is specifically the actual data (hereafter, SS curve) of the relationship of the stress and a deformation | transformation acquired by the tension test.

Hereinafter, an example of the calculation method of the principal stress S which generate | occur | produces in the wiring layer 12 in the case of using an SS curve as a relationship between the stress and strain in each layer is demonstrated. In this method, first, a tensile test is performed on each of the materials constituting each layer (hereinafter referred to as a constituent material) to obtain an SS curve. Next, the laminated body 1 is divided into the several calculation steps which are fine enough so that calculation may not diverge from the straight state to the curved state at the time of a bending test. Next, in the SS curve of each constituent material, the inclination for each calculation step is calculated. The inclination for each calculation step is an elasticity modulus for each calculation step in each constituent material. Next, the elastic modulus for each calculation step in each of the constituent materials thus obtained is used instead of the elastic modulus used in the series of calculations of the formulas (1) to (7), and the laminate 1 is updated by the updated Lagrange method. From the straight state to the curved state during the bending test, a series of calculations of formulas (1) to (7) are repeated for each calculation step, and the wiring layer 12 is generated in the curved state during the bending test. Calculate the principal stress (S). According to the calculation method of the principal stress S using the updated Lagrange method, even when the relationship between the stress and the deformation (SS curve) in each layer is nonlinear, it is possible to calculate the principal stress S with high accuracy. do.

As explained above, according to this embodiment, with respect to the virtual laminated body 1C, the thickness of each layer which comprises the virtual laminated body 1C, and each layer which comprises the virtual laminated body 1C is shown. Relationship between stress and deformation in the gap, the gap H between the fixed plate 21 and the movable plate 22 in the bending test, and the line width LW in the wiring layer 12 of the virtual laminate 1C. ) And the stress (main stress) generated in the wiring layer 12 of the virtual laminate 1C, using the information of the line width SW, and based on the calculated stress and the stress-flex life relationship. Thus, it is possible to predict the bending life N of the virtual laminate 1C. In the present embodiment, when predicting the bending life N of the virtual laminate 1C, it is not necessary to actually test the laminate 1. In addition, in this embodiment, the bending lifetime N of the virtual laminated body 1C can be predicted by the calculation using each said information, without using a finite element method. Therefore, according to this embodiment, it becomes possible to easily set the conditions of each layer which comprises the laminated body 1, and to predict the bending life of the laminated body 1 easily. Moreover, according to this embodiment, it becomes also possible to calculate | require the preferable combination of the conditions of each layer which comprises the laminated body 1. As shown in FIG.

In addition, this invention is not limited to each said embodiment, A various change is possible. For example, the laminated body to which this invention is applied is not limited to the FPC in which a wiring layer was provided only in one surface of a base layer, but the FPC in which wiring layers were provided in both surfaces of a base layer may be sufficient.

Based on the above description, it is clear that various aspects and modifications of this invention can be implemented. Therefore, in the equal range of the following claims, even if it is a form other than said best form, it is possible to implement this invention.

One… Laminate 11... Base layer
12... Wiring layer 13.. Adhesive layer
14... Cover layer 21... Fixed plate
22... Movable plate 30.. Flexural Life Prediction Device

Claims (12)

The laminate is provided between a fixed plate and a movable plate having a plurality of laminated layers including a base layer and a wiring layer made of a patterned conductor and extending in one direction and arranged at predetermined intervals with respect to the bendable laminate. Flexure measured by a flexural test performed by bending the U-shape and fixing each end in the longitudinal direction of the laminate to the fixed plate and the movable plate, and reciprocating the movable plate in a direction parallel to the plane. As a method of predicting lifespan,
For each of the samples of the plurality of laminates having different configurations, the thickness of each layer constituting the sample, the relationship between stress and strain in each layer constituting the sample, and the bending test A first calculation procedure for calculating stress generated in the wiring layer of the sample by using the information between the interval between the fixed plate and the movable plate, and the line width and the line width in the wiring layer of the sample;
A procedure for measuring a bending life by the bending test for each of the plurality of samples;
The said wiring layer in the said laminated body of arbitrary structures based on the stress which arises in the wiring layer of each sample computed by the said 1st calculation procedure, and the bending life of each sample measured by the procedure which measures the said bending life. The procedure for obtaining the relationship between stress and bending life
For the virtual laminate as a target for predicting the bending life, the thickness of each layer constituting the virtual laminate, the relationship between stress and strain in each layer constituting the virtual laminate, and the bending 2nd calculation which calculates the stress which arises in the wiring layer of the said virtual laminated body using each information of the space | interval of the fixed board and movable board in a test, and the line width and the line width in the wiring layer of the said virtual laminated body. Procedure,
The said virtual based on the relationship between the stress which arises in the wiring layer of the said virtual laminated body computed by the said 2nd calculation procedure, and the said stress calculated | required by the procedure which calculates the relationship of the said stress and a bending life, and the said bending life. A method for predicting the bending life of a laminate, comprising a procedure for predicting the bending life of the laminate. The method of claim 1, wherein the elastic modulus of the material constituting the layers is used as a relationship between stress and strain in the layers. The method of claim 1, wherein the relationship between stress and strain in each layer is obtained by a tensile test on the material constituting each layer. The main stress as set forth in claim 1, wherein in the first calculation procedure, a main stress obtained from vertical stress and shear stress as stress generated in the wiring layer of the sample is calculated.
In the second calculation procedure, the principal stress obtained from the vertical stress and the shear stress is calculated as the stress generated in the wiring layer of the virtual laminate, characterized in that the bending life prediction method of the laminate. The procedure according to claim 1, wherein the relationship between the stress generated in the wiring layer and the life span of the wiring layer in which the temperature at the time of the bending test is performed as a parameter is determined in the procedure for obtaining the relationship between the stress and the bending life.
In the procedure for predicting the bending life, the bending life of the virtual laminate under an arbitrary temperature is determined based on the relationship between the stress calculated by the second calculation procedure, the stress with the temperature as the parameter, and the bending life. Prediction method of bending life of a laminate. The procedure according to claim 1, wherein the relationship between the stress generated in the wiring layer and the bending life is obtained by setting the frequency of the reciprocating motion of the movable plate in the bending test as a parameter. ,
In the procedure for predicting the bending life, the bending life of the virtual laminate under an arbitrary frequency is based on the relationship between the stress calculated by the second calculation procedure, the stress with the frequency as the parameter, and the bending life. Flexural life prediction method of the laminate, characterized in that for predicting. The laminate is provided between a fixed plate and a movable plate having a plurality of laminated layers including a base layer and a wiring layer made of a patterned conductor and extending in one direction and arranged at predetermined intervals with respect to the bendable laminate. Flexure measured by a flexural test performed by bending the U-shape and fixing each end in the longitudinal direction of the laminate to the fixed plate and the movable plate, and reciprocating the movable plate in a direction parallel to the plane. As a device for predicting lifetime,
For each of the samples of the plurality of laminates having different configurations, the thickness of each layer constituting the sample, the relationship between stress and strain in each layer constituting the sample, and the bending test First input means for inputting information of the interval between the fixed plate and the movable plate, and the line width and 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;
Second input means for inputting each bending life of the plurality of samples measured by the bending test;
The stress generated in the wiring layer of each sample calculated by the first calculating means and the wiring layer in the laminate of any configuration based on the bending life of each sample input by the second input means. Means for determining the relationship between stress and bending life
For the virtual laminate as a target for predicting the bending life, the thickness of each layer constituting the virtual laminate, the relationship between stress and strain in each layer constituting the virtual laminate, and the bending Third input means for inputting information of the interval between the fixed plate and the movable plate in the test, 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 information input by the third input means;
The virtual 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 calculated by the means for obtaining the relationship between the stress and the bending life. And a means for predicting the bending life of the laminate. The said first calculation means calculates the main stress calculated | required from a normal stress and a shear stress as a stress which arises in the wiring layer of the said sample,
And said second calculating means calculates a main stress obtained from vertical stress and shear stress as stress generated in the wiring layer of said virtual laminate. The method according to claim 7, wherein the means for calculating the relationship between the stress and the bending life is obtained by obtaining a relationship between the stress generated in the wiring layer and the bending life using the temperature when the bending test is performed as a parameter.
The means for predicting the bending life is based on the relationship between the stress calculated by the second calculating means, the stress with the temperature as the parameter and the bending life, and the bending life of the virtual laminate under an arbitrary temperature. Bending life prediction apparatus for a laminate, characterized in that for predicting. 8. The means for obtaining a relationship between the stress and the bending life is according to claim 7, wherein the relationship between the stress and the bending life generated in the wiring layer in which the frequency of the reciprocating motion of the movable plate in the bending test is a parameter. Obtaining
The means for predicting the bending life is based on the relationship between the stress calculated by the second calculating means, the stress with the frequency as the parameter, and the bending life, and the bending life of the virtual laminate under an arbitrary frequency. Bending life prediction apparatus for a laminate, characterized in that for predicting. The laminate is provided between a fixed plate and a movable plate having a plurality of laminated layers including a base layer and a wiring layer made of a patterned conductor and extending in one direction and arranged at predetermined intervals with respect to the bendable laminate. Flexure measured by a flexural test performed by bending the U-shape and fixing each end in the longitudinal direction of the laminate to the fixed plate and the movable plate, and reciprocating the movable plate in a direction parallel to the plane. To predict lifespan,
For each of the samples of the plurality of laminates having different configurations, the thickness of each layer constituting the sample, the relationship between stress and strain in each layer constituting the sample, and the bending test First input means for inputting respective pieces of information of the line width and line width in the wiring layer of the sample and the gap between the fixed plate and the movable plate;
Second calculation means for calculating a stress generated in the wiring layer of the sample by using the information input by the first input means,
Second input means for inputting each bending life of the plurality of samples measured by the bending test,
The stress generated in the wiring layer of each sample calculated by the first calculating means and the wiring layer in the laminate of any configuration based on the bending life of each sample input by the second input means. Means for determining the relationship between stress and bending life
For the virtual laminate as a target for predicting the bending life, the thickness of each layer constituting the virtual laminate, the relationship between stress and strain in each layer constituting the virtual laminate, and the bending Third input means for inputting respective information of the line width and the line width in the wiring layer of the virtual laminate, and the interval between the fixed plate and the movable plate in the test;
Second calculation means for calculating stress generated in the wiring layer of the virtual laminate using information input by the third input means, and
The virtual 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 calculated by the means for obtaining the relationship between the stress and the bending life. A bending life prediction program of a laminate for functioning as a means for predicting the bending life of the laminate. A computer-readable recording medium recording a bending life prediction program of a laminate,
The program includes a plurality of stacked layers including a base layer and a wiring layer made of a patterned conductor, and extends in one direction and is disposed between the fixed plate and the movable plate at predetermined intervals with respect to the bendable laminate. By a bending test performed by bending the laminate into a U shape and fixing each end in the longitudinal direction of the laminate to the fixed plate and the movable plate, and reciprocating the movable plate in a direction parallel to the plane. In order to predict the bend life measured, the computer,
For each of the samples of the plurality of laminates having different configurations, the thickness of each layer constituting the sample, the relationship between stress and strain in each layer constituting the sample, and the bending test First input means for inputting respective pieces of information of the line width and line width in the wiring layer of the sample and the gap between the fixed plate and the movable plate;
First calculation means for calculating a stress generated in the wiring layer of the sample by using the information input by the first input means,
Second input means for inputting each bending life of the plurality of samples measured by the bending test,
On the wiring layer in the laminate of any configuration, 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. Means for determining the relationship between stress and bending life
For the virtual laminate as a target for predicting the bending life, the thickness of each layer constituting the virtual laminate, the relationship between stress and strain in each layer constituting the virtual laminate, and the bending Third input means for inputting respective information of the line width and the line width in the wiring layer of the virtual laminate, and the interval between the fixed plate and the movable plate in the test;
Second calculation means for calculating stress generated in the wiring layer of the virtual laminate using information input by the third input means, and
The virtual 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 calculated by the means for obtaining the relationship between the stress and the bending life. And a function of predicting the bending life of the stack.

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