JP2017067456A - Hit point test device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a test device capable of evaluating durability of a hit point of a flexible printed circuit (FPC) in a simple configuration.SOLUTION: A hit point test device 100 includes: a sample fixing part 20 for fixing an FPC 10; a load application part 30 for continuously applying a load to the FPC 10 fixed to the sample fixing part 20; a measurement part 40 which is connected to wires of the FPC 10 so as to detect electrical parameters of the wires; and a controller 50 for controlling each component of the hit point test device 100. The measurement part 40 detects a resistance value, a current value, and a voltage value by continuously or intermittently applying current to the FPC 10 fixed to the sample fixing part 20 during a test.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a dot test apparatus, and more particularly, to a dot test apparatus for evaluating the dot durability of a flexible printed wiring board.

  In recent years, with the progress of downsizing, weight reduction, and space saving of electronic devices, flexible printed wiring boards (FPCs) that are thin, light, flexible, and have excellent durability even after repeated bending are used. The demand for Circuits) is increasing. FPC can be mounted three-dimensionally and densely in a limited space. For example, it can be used for wiring of movable parts of electronic devices such as HDDs, DVDs, mobile phones, smartphones, cables, connectors, etc. Applications are expanding.

  By the way, since a pressing force is repeatedly applied to a movable part such as a switch of an electronic device, there is a concern about occurrence of problems such as poor connection due to wiring breakage in the FPC used in the movable part. Therefore, in order to improve the reliability of electronic equipment, it is required to accurately evaluate the hit point durability of FPC.

  Patent Document 1 proposes a testing device devised so as to change the keying position in the horizontal direction by imitating the displacement of the pressing position in the actual machine in the keying durability test for the transparent conductive film of the resistive touch panel. Yes. Patent Document 2 proposes a device that detects a stroke and a pressing force when a side key provided on a side portion of a mobile phone or the like is clicked.

JP 2009-42817 A JP 2014-186802 A

  As described above, a technique for performing a key-stroke test on parts such as a touch panel and a key used in an electronic device has been proposed, but a method capable of directly evaluating the hit point durability against FPC has not been reported.

  An object of the present invention is to provide a test apparatus that can evaluate the hit point durability of an FPC with a simple configuration.

The dot test apparatus for flexible printed wiring boards of the present invention is
A sample fixing part for fixing a flexible printed wiring board;
A load applying unit that repeatedly applies a load to the flexible printed wiring board fixed to the sample fixing unit by an indenter that reciprocates at a constant movement amount;
A measurement unit connected to the wiring of the flexible printed wiring board to detect its electrical parameters;
It has.

In the dot test apparatus for flexible printed wiring board of the present invention,
The sample fixing part is
A base for supporting the flexible printed wiring board;
An elastic member interposed between the base and the flexible printed wiring board;
May be provided.

  In the dot test apparatus for a flexible printed wiring board of the present invention, the elastic member may be a dome spring.

  In the dot test apparatus for a flexible printed wiring board of the present invention, the sample fixing part may further include a horizontal driving part that moves the base in a horizontal direction.

  In the dot test apparatus for a flexible printed wiring board of the present invention, the amount of movement of the indenter is further a predetermined distance from a position at which application of a load is started to the flexible printed wiring board fixed to the sample fixing portion. The flexible printed wiring board may be set to be pushed in.

  In the dot test apparatus for flexible printed wiring boards of the present invention, the electrical parameter may be a resistance value, a current value, or a voltage value.

The dot test apparatus for a flexible printed wiring board of the present invention may be a double-sided flexible printed wiring board in which the flexible printed wiring board has wiring on both sides,
The measurement unit may be connected to the wirings on both sides of the double-sided flexible printed wiring board and individually detect the electrical parameters.

  Since the spot testing device for FPC of the present invention includes a measuring unit that is connected to the wiring of the FPC and detects its electrical parameters, the spot durability of the FPC can be ensured despite the simple configuration. Can be evaluated. By evaluating the durability of the FPC using the FPC dot test apparatus of the present invention, the reliability of the FPC can be improved, and further the operational reliability of the electronic device using the FPC can be improved.

It is a schematic block diagram of the dot test apparatus of one embodiment of this invention. It is a disassembled perspective view which shows one structural example of a sample fixing | fixed part. It is principal part sectional drawing which shows the state which laminated | stacked the resin sheet and the flexible printed wiring board. It is a disassembled perspective view which shows another structural example of a sample fixing | fixed part. It is principal part sectional drawing which shows the state which laminated | stacked the resin sheet and the bent flexible printed wiring board. It is a schematic diagram explaining the state where the indenter has reached the zero point position. It is a schematic diagram explaining the additional pushing amount from a zero point position.

  Hereinafter, a flexible printed wiring board (FPC) dot test apparatus (hereinafter, simply referred to as “dot test apparatus”) according to an embodiment of the present invention will be described with reference to the drawings as appropriate. FIG. 1 is a schematic configuration diagram of a dot test apparatus 100 according to the present embodiment. The spot test apparatus 100 according to the present embodiment is connected to a sample fixing unit 20 that fixes the FPC 10, a load application unit 30 that repeatedly applies a load toward the FPC 10 fixed to the sample fixing unit 20, and wiring of the FPC 10. And a control unit 50 that controls each component of the hit point test apparatus 100.

<Sample>
In the dot test apparatus 100 of the present embodiment, the sample to be tested is the FPC 10. The FPC 10 has a known configuration, and although not described in detail, the FPC 10 is a flexible circuit board having a resin layer and wiring formed on one side or both sides of the resin layer.

<Sample fixing part>
FIG. 2 is an exploded perspective view illustrating a configuration example of the sample fixing unit 20. In this example, the sample fixing unit 20 includes a base 21, a spring unit 20A having an elastic member 22, and a resin sheet unit 20B including a plurality of resin sheets.

(Base)
The base 21 is a member made of metal such as aluminum, for example, and a concave portion 21a for positioning and fixing a sheet fixing plate 27 and an FPC 10 described later is formed on the upper surface thereof.

(Spring unit)
FIG. 2 shows an example of the spring unit 20 </ b> A having the elastic member 22 in the sample fixing unit 20. In this example, the holder 23 that holds the elastic member 22, the elastic member 22, and the pressing member 24 that presses the elastic member 22 from above are stacked in this order from the base 21 side.

  The elastic member 22 is disposed between the base 21 and the FPC 10. By utilizing the elastic deformation by the elastic member 22, it is possible to apply a bending stress imitating the movement of an actual electronic device to the flexible FPC 10.

  As the elastic member 22, for example, a metal spring such as SUS can be used, and it is preferable to use a dome spring, a leaf spring, a coil spring or the like. Among these, a general purpose is used for a switch part of an actual electronic device. More preferred is a dome spring.

  The holder 23 is a member having a hollow cylindrical shape made of metal such as SUS. The holder 23 is positioned by being fitted into a recess 21 a formed in the base 21. The elastic member 22 such as a dome spring is arranged in alignment with the hollow portion of the holder 23 so that the center thereof is aligned.

  The pressing member 24 is a member having a disk shape made of metal such as SUS. The holding member 24 is fixed by sandwiching the elastic member 22 between the holder 23 and the holder 23.

(Resin sheet unit)
The sample fixing unit 20 may include a plurality of resin sheets in order to stably fix the FPC 10 and to approximate an environment such as a switch unit of an actual electronic device. The plurality of resin sheets function as a cushioning material that is laminated above or below the FPC 10 or inserted between the folded FPCs 10 to provide appropriate cushioning and soften the load applied by the indenter 31.

  In FIG. 2, an example of the resin sheet unit 20B including a plurality of resin sheets in the sample fixing unit 20 is shown. In the example illustrated in FIG. 2, the resin sheet unit 20 </ b> B includes a lower resin sheet 25, an upper resin sheet 26, and a sheet fixing plate 27 in order from the base 21 side.

  The lower resin sheet 25 is disposed on the base 21 side below the FPC 10, for example, between the FPC 10 and the elastic member 22. The upper resin sheet 26 is disposed on the indenter 31 side above the FPC 10, for example, between the FPC 10 and the sheet fixing plate 27. At the time of testing, the lower resin sheet 25 and the upper resin sheet 26 are stacked on the FPC 10 as shown in FIG. 3, for example, and are arranged so as to sandwich the FPC 10 from above and below. Thereby, it functions as a buffer material against a load (indicated by a white arrow in FIG. 3) due to the indenter 31. In FIG. 3, for convenience of explanation, the thicknesses of the FPC 10, the lower resin sheet 25, and the upper resin sheet 26 are exaggerated.

  The lower resin sheet 25 and the upper resin sheet 26 are preferably made of, for example, a material such as polytetrafluoroethylene (PTFE) resin, silicone resin, or urethane resin in order to approximate an environment such as a switch part of an actual electronic device. . In addition, the thickness of these resin sheets is preferably in the range of 0.1 mm to 1.0 mm, for example, in order to have a sufficient buffering action against the load by the indenter 31. Each of the lower resin sheet 25 and the upper resin sheet 26 is not limited to one sheet, and two or more sheets may be used.

  The sheet fixing plate 27 is a metal flat plate made of, for example, SUS. Further, the outer edge of the sheet fixing plate 27 has a rectangular shape as a whole corresponding to the contour of the recess 21 a of the base 21. The sheet fixing plate 27 can be positioned by fitting into the recess 21a.

  The sheet fixing plate 27 is a metal flat plate made of, for example, SUS, and is laminated with the lower resin sheet 25, the FPC 10, the bending resin sheet 28 (described later), and the upper resin sheet 26 arranged as necessary. Is fixed by pressing from above. With the sheet fixing plate 27, the FPC 10 as the sample can be securely fixed so as not to be displaced during the test.

  FIG. 4 is an exploded perspective view of the sample fixing portion showing another example of the resin sheet unit 20B having a plurality of resin sheets in the sample fixing portion 20. In the example shown in FIG. 4, the resin sheet unit 20 </ b> B includes a lower resin sheet 25, a bending resin sheet 28, an upper resin sheet 26, and a sheet fixing plate 27 in order from the base 21 side. Here, since the configuration other than the bending resin sheet 28 in FIG. 4 is the same as that in FIG. 2, the same components are denoted by the same reference numerals and description thereof is omitted.

  The bending resin sheet 28 is inserted between the bent FPCs 10 when the hitting test is performed in a state where the FPCs 10 are bent and stacked in a multilayer of two or more layers. At the time of the test, the bending resin sheet 28 is laminated and arranged so as to be sandwiched from above and below by the FPC 10 in a bent state, for example, as shown in FIG. Thereby, it functions as a cushioning material against a load (indicated by a white arrow in FIG. 5) due to the indenter 31. Further, by appropriately selecting the thickness of the bending resin sheet 28 with respect to the thickness of the FPC 10, the radius of curvature of the bent portion 10a of the FPC 10 can be arbitrarily set. The storage state of the FPC 10 can be reproduced. In FIG. 5, for convenience of explanation, the thicknesses of the FPC 10, the lower resin sheet 25, the upper resin sheet 26, and the bending resin sheet 28 are exaggerated.

  The bending resin sheet 28 is preferably made of, for example, a material such as polytetrafluoroethylene (PTFE) resin, silicone resin, or urethane resin in order to approximate the environment such as a switch part of an actual electronic device. Further, the thickness of the bending resin sheet 28 is preferably in the range of 0.1 mm to 1.0 mm, for example, in order to have a sufficient buffering action against the load by the indenter 31. Note that the bending resin sheet 28 is not limited to one, but may be two or more, and may not be disposed when the FPC 10 is subjected to a single-layer dot test.

  In the configuration examples shown in FIGS. 2 to 5, the lower resin sheet 25 and the upper resin sheet 26 are arbitrary configurations and do not necessarily have to be arranged.

(Horizontal drive unit)
The sample fixing unit 20 further includes a horizontal driving unit 29 that moves the base 21 in the horizontal direction (XY direction). Although not shown, the horizontal drive unit 29 is, for example, an X-axis actuator that moves the base 21 along the X-axis guide, a Y-axis actuator that moves the base 21 along the Y-axis guide, An encoder or the like provided on each of the Y axes is provided. As the X-axis actuator and Y-axis actuator, for example, a linear motor, an air cylinder, a ball screw, or the like can be used. The horizontal drive unit 29 can move the base 21 in the XY direction within a range of, for example, ± 50 mm. The horizontal drive unit 29 makes it possible to apply a load to a position where the center of the indenter 31 deviates from the center of the elastic member 22 such as a dome spring. Therefore, it is possible to perform a test simulating the eccentricity of the pressing force when operating the switch unit of an actual electronic device.

<Load application part>
The load application unit 30 includes an indenter 31 for applying a load to the FPC 10, a Z-axis drive unit 32 that linearly reciprocates the indenter 31 in the Z-axis direction (vertical direction) with a constant movement amount (stroke), and an indenter 31 and the shaft part 33 which connects the Z-axis drive part 32 are provided.

  The indenter 31 has a cylindrical shape as a whole, and a tip portion of the indenter 31 has a rounded conical shape. Although not shown, the indenter 31 is configured by a metal core made of, for example, SUS or the like and a resin layer that covers the metal core. As resin which comprises a resin layer, a urethane resin, a polyacetal resin, a silicone resin etc. can be used, for example. The hardness of the tip portion of the indenter 31 is preferably in the range of Shore hardness A50 to Rockwell hardness M90, for example, from the viewpoint of the usage pattern of the electronic device on which the FPC is mounted. In addition, the radius of curvature of the tip portion of the indenter 31 is preferably in the range of 0.8 mm to 12 mm, for example, from the viewpoint of the usage pattern of the electronic device on which the FPC is mounted.

(Z-axis drive unit)
Although not shown, the Z-axis drive unit includes an actuator such as an air cylinder, a load cell for detecting a load, and the like.

  The load application unit 30 is configured to apply a preset load to the FPC 10 fixed to the sample fixing unit 20 by the indenter 31.

Further, the load application unit 30 can further push the FPC 10 at a predetermined distance from the position (zero point position) where the application of the load by the indenter 31 is started to the FPC 10 fixed to the sample fixing unit 20. The amount of movement of the indenter 31 can be set. Figure 6 shows a state in which the indenter 31 has reached the zero point position P ₀ schematically. FIG. 7 schematically shows a state where the indenter 31 is further pushed to the position P ₁ from the zero point position P ₀ shown in FIG. 6 and 7, for convenience of explanation, the thicknesses of the FPC 10, the lower resin sheet 25, and the upper resin sheet 26 are exaggerated. Here, the additional pushing amounts P _{0 to} P ₁ by the indenter 31 can be arbitrarily set within a range of 0.1 mm to 1.9 mm, for example. Thus, the RBI test apparatus 100, since it performs the durability test using the elastic deformation of the elastic member 22, by such an additional push amount P ₀ to P ₁ can be set variably, flexible It is possible to evaluate the hit point durability specialized for the FPC 10 having

<Measurement unit>
During the test, the measuring unit 40 continuously or intermittently passes a current through the FPC 10 fixed to the sample fixing unit 20 to detect an electrical parameter. Examples of electrical characteristics detected by the measurement unit 40 include a resistance value, a current value, and a voltage value. Among these, it is preferable to detect a resistance value that can easily detect a change due to disconnection of the wiring.

  The measuring unit 40 is connected to the wiring (not shown) of the FPC 10 by a lead wire 41. The lead wire 41 is connected to both sides of an arbitrary wiring with a portion to which a load is applied interposed therebetween. In FIG. 1, only two lead wires 41 are representatively shown. When the FPC 10 is a double-sided FPC having wirings on both sides, the measurement unit 40 is configured to be individually connected to the wirings on both sides with lead wires 41 and to individually detect electrical parameters of the wirings on both sides. ing.

<Control unit>
The control unit 50 controls each component of the hit point test apparatus 100. The control unit 50 is typically a computer, and includes a main control unit having a CPU (Central Processing Unit) and a RAM (Random Access Memory), an input device such as a keyboard and a mouse, an output device such as a printer, and a display. And a storage device such as a hard disk.

  The control unit 50 performs control so that a dot test for the FPC 10 can be performed in the dot test apparatus 100 of the present embodiment. Specifically, the control unit 50 controls each component (for example, the horizontal drive unit 29, the load application unit 30, the measurement unit 40, etc.) of the spot test device 100. These are realized by the CPU of the main control unit 50 executing software (program) stored in the storage device using the RAM as a work area.

  In the hitting test apparatus 100 having the above configuration, the hitting test on the FPC 10 can be performed by appropriately setting the number of times the indenter 31 is driven, the driving load, the driving speed, the amount of movement of the indenter 31, and the like.

  For example, when measuring the resistance value, the measurement unit 40 applies a current of 1.0 V / 10 mA or less to the wiring of the FPC 10 to calculate the ratio of the measured value to the initial resistance value. The control unit 50 determines the durability of the FPC by comparing the ratio of the measurement values obtained by the measurement unit 40 with a predetermined threshold value, and displays the result on a display, for example.

<Test procedure>
Next, an example of a test procedure in the dot test apparatus 100 will be described. Here, a case where a resistance value is measured as an electrical parameter is taken as an example.

  First, the FPC 10 is set on the sample fixing unit 20. When the FPC 10 is set in a folded state, a bending resin sheet 28 is interposed. And the wiring of the single side | surface or both surfaces of FPC10 and the measurement part 40 are connected by the lead wire 41, and an initial stage resistance value is measured.

  Next, the indenter 31 of the load application unit 30 is lowered to apply a load to the FPC 10 to detect the zero point position. If necessary, the driving distance is set so that the FPC 10 is pushed toward the base 21 side at a predetermined distance from the zero point position.

  Next, by moving the indenter 31 up and down, the FPC 10 is pressed at a set driving distance, and a predetermined load is repeatedly applied. During this time, the measurement unit 40 measures the resistance value continuously or intermittently, and calculates the ratio (variation ratio) between the measured resistance value and the initial resistance value. Then, the control unit 50 compares the obtained fluctuation ratio of the resistance value with a predetermined threshold value, and determines that a failure such as disconnection has occurred in the FPC 10 when the fluctuation ratio exceeds the threshold value. On the other hand, even if the number of times set in advance is performed, if the variation ratio is equal to or less than the threshold value, it is possible to determine that the hit point durability of the FPC 10 is acceptable.

  In the evaluation of the hit point durability, the evaluation can be performed based on various information obtained from the detected resistance value. For example, instead of comparing the fluctuation ratio with a threshold value, the resistance value may be directly compared with a threshold value set appropriately in advance, or the rate of change of the resistance value within a predetermined time may be calculated. The evaluation may be performed by monitoring and comparing the rate of change with a threshold value. The same applies to the case where a parameter other than the resistance value is used as the electrical parameter.

  As described above, according to the dot test apparatus 100 of the present embodiment, the measuring unit 40 connected to the wiring of the FPC 10 and detecting the electrical parameter is provided, so that it has a simple configuration. The durability of the hit point of the FPC 10 can be reliably evaluated.

  In addition, the dot test apparatus 100 according to the present embodiment supports not only a single-sided FPC having wiring on one side but also a double-sided FPC having wiring on both sides, and simultaneously detects electrical parameters of wirings on both sides. it can. Therefore, it is possible to quickly perform a dot test for a double-sided FPC.

  Moreover, since the spot test apparatus 100 of the present embodiment includes the elastic member 22 in the sample fixing unit 20, a predetermined load can be applied by imitating the movement of a switch unit of an actual electronic device. Therefore, the hit point durability of the FPC 10 can be evaluated in a state close to the actual use environment.

  In addition, since the spot test apparatus 100 according to the present embodiment includes the resin sheet unit 20B including a plurality of resin sheets, the spot resistance of the FPC 10 is maintained under a condition that approximates the environment such as a switch unit of an actual electronic device. Sex can be evaluated. When the bending resin sheet 28 is used, the test can be performed by reproducing the state in which the FPC 10 is folded and stored inside an actual electronic device.

  Furthermore, since the spot test apparatus 100 of the present embodiment includes the horizontal drive unit 29 that moves the base 21 in the horizontal direction (XY direction), the position where the center of the indenter 31 deviates from the center of the elastic member 22. It is possible to apply a load to the sensor, and it is possible to perform a test simulating the eccentricity of the pressing force during the operation of the switch part of an actual electronic device.

  As described above, by evaluating the durability of the FPC 10 using the dot test apparatus 100 of the present embodiment, the reliability of the FPC 10 is improved, and further, the operation reliability of the electronic device using the FPC 10 is improved. be able to.

  As mentioned above, although embodiment of this invention was described in detail for the purpose of illustration, this invention is not restrict | limited to the said embodiment.

  DESCRIPTION OF SYMBOLS 10 ... Flexible printed wiring board (FPC), 10a ... Bending part, 20 ... Sample fixing part, 21 ... Base, 21a ... Recessed part, 22 ... Elastic member, 23 ... Holder, 24 ... Holding member, 25 ... Lower resin sheet , 26 ... Upper resin sheet, 27 ... Sheet fixing plate, 28 ... Bending resin sheet, 29 ... Horizontal drive unit, 30 ... Load application unit, 31 ... Indenter, 32 ... Z-axis drive unit, 33 ... Shaft unit, 40 ... Measurement unit, 41 ... Lead wire, 50 ... Control unit, 100 ... Dot test device for flexible printed wiring board (FPC)

Claims (7)

A sample fixing part for fixing a flexible printed wiring board;
A load applying unit that repeatedly applies a load to the flexible printed wiring board fixed to the sample fixing unit by an indenter that reciprocates at a constant movement amount;
A measurement unit connected to the wiring of the flexible printed wiring board to detect its electrical parameters;
A dot test apparatus for flexible printed wiring boards comprising: The sample fixing part is
A base for supporting the flexible printed wiring board;
An elastic member interposed between the base and the flexible printed wiring board;
The dot test apparatus for flexible printed wiring boards according to claim 1, comprising:   The impact test apparatus for a flexible printed wiring board according to claim 2, wherein the elastic member is a dome spring.   The said sample fixing | fixed part is a dot test apparatus for flexible printed wiring boards of Claim 2 or 3 further provided with the horizontal drive part which moves the said base to a horizontal direction.   The amount of movement of the indenter is set so as to push the flexible printed wiring board at a predetermined distance from a position at which application of a load is started to the flexible printed wiring board fixed to the sample fixing portion. The dot test apparatus for flexible printed wiring boards according to any one of claims 1 to 4.   The impact test apparatus for a flexible printed wiring board according to any one of claims 1 to 5, wherein the electrical parameter is a resistance value, a current value, or a voltage value. The flexible printed wiring board is a double-sided flexible printed wiring board having wiring on both sides,
The flexible printed wiring according to any one of claims 1 to 6, wherein the measuring unit is connected to the wirings on both sides of the double-sided flexible printed wiring board and individually detects the electrical parameters. Plate dot test equipment.

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