JP3991255B2 - Drop impact measuring method and drop impact measuring apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The invention of the present application relates to a method and an apparatus for measuring an impact received by a measurement object by dropping.
[0002]
[Prior art]
For example, a board on which various parts are mounted by soldering is incorporated in an electronic device, and if the electronic device receives an impact due to a fall on the floor or the like due to an unexpected accident, the board itself may be damaged or the board may be damaged. In some cases, the electronic device becomes inoperable due to an increase in the resistance value of the solder joint due to a crack generated in the solder joint between the component and the part. Therefore, a drop impact test is performed in order to evaluate the reliability of the substrate and the like against the drop impact and to consider measures for preventing damage to the substrate and the like due to the drop impact.
[0003]
In a conventional general drop impact test, a board on which a component is mounted is incorporated into an electronic device in actual use to make a product, and the electronic device as this product is placed on a rotating plate at a predetermined height from the floor. The electronic device was freely dropped on the floor surface by rotating the rotating plate, and the operating state of the electronic device that received the drop impact was confirmed.
[0004]
In addition, as a drop impact test, there is also a test for confirming the operating state of an electronic device that has received a drop impact by applying an acceleration to an electronic device as a product to forcibly drop it. However, in this drop impact test, the mass of the electronic device as a product is related to the drop impact, whereas the influence of the mass on the drop impact is very small only with a downsized board or component. Therefore, this drop impact test for performing a forced drop is not appropriate as a test only for substrates and parts that are becoming smaller.
[0005]
[Problems to be solved by the invention]
However, in the above-described conventional example that confirms the operating state of an electronic device that has received an impact due to free fall, it has not been possible to quantitatively measure the amount of distortion and the amount of deflection due to the drop impact received by the substrate or the like. In addition, in the above-described conventional example in which a drop impact is applied to an electronic device as a product, the cost of the electronic device as a product is high, so a large number of electronic devices cannot be tested, and variations due to substrates and the like. It was difficult to obtain accurate test results with a small amount. For this reason, in the above-described conventional example, it has been difficult to devise a measure for mitigating the drop impact received by the substrate or the like and preventing the substrate or the like from being damaged.
[0006]
Therefore, the invention of the present application can quantitatively measure the amount of distortion and the amount of deflection due to the drop impact received by the measurement object, and moreover, the amount of distortion and the deflection due to the accurate drop impact with little variation due to the measurement object. in order to be able to measure the amount, providing a likely drop impact measurement method and drop impact measuring device consider measures to prevent damage of the measurement object by mitigating drop impact of the measurement object is subjected It is aimed.
[0007]
[Means for Solving the Problems]
In the drop impact measurement method according to claim 1, the strain when the measurement object is subjected to the drop impact by the strain gauge attached to the measurement object and the laser displacement meter in a non-contact state with the measurement object. Since the step of measuring the amount and the amount of deflection is provided, it is possible to quantitatively measure the amount of distortion and the amount of deflection caused by the drop impact received by the measurement object.
[0008]
Moreover, since the amount of distortion and the amount of deflection can be measured directly only from the object to be measured, even if the object to be measured operates in a state where it is incorporated in another article, it is incorporated in another article. Therefore, it is not necessary to measure the amount of distortion and the amount of deflection due to the drop impact indirectly from the operation in the state where the movement is performed. For this reason, it is possible to measure a large number of measurement objects while suppressing an increase in measurement cost, and it is possible to measure the amount of distortion and the amount of deflection due to an accurate drop impact with little variation due to the measurement objects. .
[0009]
Further, since the strain gauge is generally small, the measurement position of the strain amount in the measurement object can be selected by selecting the position where the strain gauge is attached to the measurement object. In addition, since the strain gauge is generally light, even if the strain amount of the measurement object is measured with the strain gauge attached to the measurement object, the drop impact received by the measurement object hardly changes. For these reasons, it is possible to accurately measure the amount of distortion when the measurement object receives a drop impact.
[0010]
Moreover, the measurement position of the amount of deflection in the measurement object can be selected by selecting the irradiation position of the laser beam on the measurement object when subjected to the drop impact. In addition, since the laser displacement meter can measure the amount of deflection of the measurement object in a non-contact state with the measurement object, the measurement object receives even if the amount of deflection of the measurement object is measured by the laser displacement meter. Drop impact does not change at all. For these reasons, it is possible to accurately measure the amount of deflection when the measurement object receives a drop impact.
[0011]
In the drop impact measuring method according to claim 2, the method includes the step of measuring the resistance value of the solder joint portion in the measurement object after the measurement object receives the drop impact. From the increase in the resistance value of the solder joint due to cracks occurring in the metal, the influence of the drop impact received by the measurement object can be measured in more detail. Also, by repeating the drop impact on the same measurement object and measuring the resistance value of the solder joint, the resistance of the solder joint due to the number of drop impacts and cracks generated in the solder joint of the measurement object due to the drop impact You can know the relationship with the increase in value.
[0012]
In engaging Ru drop under shock measurement apparatus in claim 3, the strain gauge the measurement object is attached to the measurement object is measured strain amount at the time of receiving the drop impact, the measurement object in a non-contact state Since the measurement object is equipped with a laser displacement meter that measures the amount of deflection when it is subjected to a drop impact , the amount of distortion and the amount of deflection due to the drop impact received by the measurement object can be measured quantitatively. Can do.
[0013]
Moreover, since the amount of distortion and the amount of deflection can be measured directly only from the object to be measured, even if the object to be measured operates in a state where it is incorporated in another article, it is incorporated in another article. Therefore, it is not necessary to measure the amount of distortion and the amount of deflection due to the drop impact indirectly from the operation in the state where the movement is performed. For this reason, it is possible to measure a large number of measurement objects while suppressing an increase in measurement cost, and it is possible to measure the amount of distortion and the amount of deflection due to an accurate drop impact with little variation due to the measurement objects. .
[0014]
In addition , since the strain gauge is generally small, the measurement position of the strain amount on the measurement object can be selected by selecting the position where the strain gauge is attached to the measurement object. In addition, since the strain gauge is generally light, even if the strain amount of the measurement object is measured with the strain gauge attached to the measurement object, the drop impact received by the measurement object hardly changes. For these reasons, it is possible to accurately measure the amount of distortion when the measurement object receives a drop impact.
[0015]
Moreover , the measurement position of the amount of deflection in the measurement object can be selected by selecting the irradiation position of the laser beam on the measurement object when subjected to the drop impact. In addition, since the laser displacement meter can measure the amount of deflection of the measurement object in a non-contact state with the measurement object, the measurement object receives even if the amount of deflection of the measurement object is measured by the laser displacement meter. Drop impact does not change at all. For these reasons, it is possible to accurately measure the amount of deflection when the measurement object receives a drop impact.
[0016]
Since the drop impact measuring apparatus according to claim 4 includes a resistance meter for measuring the resistance value of the solder joint portion in the measurement object, the solder joint portion due to the crack generated in the solder joint portion of the measurement object due to the drop impact is provided. From the increase in the resistance value, it is possible to measure in more detail the influence of the drop impact received by the measurement object. Also, by repeating the drop impact on the same measurement object and measuring the resistance value of the solder joint, the resistance of the solder joint due to the number of drop impacts and cracks generated in the solder joint of the measurement object due to the drop impact You can know the relationship with the increase in value .
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention applied to a drop impact measuring method and a drop impact measuring apparatus for a substrate on which components are mounted and to be incorporated into an electronic device will be described with reference to FIGS. FIG. 1 shows the entire drop impact measuring apparatus of the present embodiment. The drop impact measuring device 11 is provided with a vertical plate 12, and a pair of linear guides 13 are provided on the side surface of the vertical plate 12. A movable portion 14 is attached to the linear guide 13 and is movable by being guided by the linear guide 13.
[0018]
The movable part 14 is provided with a cylinder 15 and a chuck 17 for releasing and holding the substrate 16 by opening and closing by the cylinder 15. A lever 21 for stopping the movable part 14 near the upper end of the linear guide 13 and an external part are provided. A cylinder 22 for moving the lever 21 based on the operation of the switch is attached to the vertical plate 12 by an adjusting screw 23. By adjusting the adjustment screw 23, the height of the lever 21 and the cylinder 22 can be adjusted. Therefore, the stop position of the movable portion 14 in the vicinity of the upper end portion of the linear guide 13 can be adjusted.
[0019]
A stopper 24 for stopping the movable part 14 that has fallen is attached in the vicinity of the lower end of the linear guide 13, and a detection part 25 that detects the passage of the movable part 14 and drives the cylinder 15 to release the chuck 17. Is attached to the upper end portion side of the linear guide 13 with respect to the stopper 24. A cable guide 26 that moves together with the movable portion 14 is attached to the movable portion 14, and an electric wire described later is connected between the substrate 16 and the cable guide 26.
[0020]
A cable guide 27 is fixed to the vertical plate 12, and the cable guide 26 is electrically connected to the cable guide 27. A horizontal plate 31 is fixed to the lower end portion of the vertical plate 12, and a plate 32 for causing the substrate 16 that has fallen to collide is attached to the upper surface of the horizontal plate 31. A laser displacement meter 33 is mounted on the horizontal plates 31 on both sides of the plate 32. The laser displacement meter 33 irradiates the object with a parallel laser beam 34, and calculates the amount of deflection of the object from the size of the shadow portion. taking measurement. A measurement amplifier 35 is provided on the side of the horizontal plate 31.
[0021]
FIG. 2 shows an electrical connection relationship between the substrate 16 and the laser displacement meter 33 and the measurement amplifier 35. A component 36 is mounted on the substrate 16 by a solder joint 37, and a strain gauge 38 is adhered to the substrate 16 in the vicinity of the component 36 by adhesion. The electric wire 41 connected to the strain gauge 38 is connected to the measurement amplifier 35 via the cable guides 26 and 27 and the strain amplifier 42 described above.
[0022]
A measurement land 43, which is a wiring pattern on the substrate 16, extends from the solder joint portion 37, and the electric wire 44 connected to the measurement land 43 connects the cable guides 26 and 27, the variable resistor 45 and the distortion amplifier 46 described above. To the measurement amplifier 35. The strain amplifier 46 is originally an amplifier for measuring the resistance value of the strain gauge 38 in the same manner as the strain amplifier 42. However, the resistance value of the variable resistor 45 is adjusted to adjust the resistance between the solder joint 37 and the variable resistor 45. By making the total resistance value equal to the initial resistance value of the strain gauge 38, the resistance value of the solder joint portion 37 can be measured by the strain amplifier 46.
[0023]
The electric wire 47 connected to the laser displacement meter 33 is connected to the measurement amplifier 35 via the voltage output amplifier 48. In FIG. 2, only one strain gauge 38 and measurement land 43 of the pair of strain gauges 38 and measurement lands 43 shows the electrical connection relationship with the measurement amplifier 35, but the other strain gauge 38 is shown. The measurement land 43 is also electrically connected to the measurement amplifier 35 in the same manner.
[0024]
In order to measure the impact received by the free fall of the substrate 16 using the drop impact measuring apparatus 11 of the present embodiment as described above, the substrate to which the electric wires 41 and 44 are connected as shown in FIG. 16 is held on the movable portion 14 by the chuck 17 as shown in FIG. 1, and the movable portion 14 is stopped near the upper end portion of the linear guide 13 by the lever 21. Then, from this state, the lever 21 is moved by driving the cylinder 22 by operating an external switch, and the movable portion 14 is freely dropped while being guided by the linear guide 13.
[0025]
Immediately before the movable part 14 drops to the vicinity of the lower end of the linear guide 13 and reaches the stopper 24, the detection part 25 detects the passage of the movable part 14 and drives the cylinder 15 to release the chuck 17. As a result, the substrate 16 is separated from the movable portion 14 and falls alone and collides with the plate 32. Therefore, the position on the plate 32 where the substrate 16 falls and the posture of the substrate 16 when receiving the drop impact are controlled, and a plurality of drop impacts can be given to the substrate 16 with high reproducibility. In addition, when the substrate 16 falls on the plate 32, the substrate 16 is not affected by the impact that the movable portion 14 receives from the stopper 24.
[0026]
FIG. 3 shows a state at the moment when the substrate 16 falls on the plate 32. At the moment when the substrate 16 falls on the plate 32, distortion and deflection are generated in the substrate 16, and the strain amount is recorded in the measurement amplifier 35 by the strain gauge 38 and the strain amplifier 42, and the laser displacement meter 33 and the voltage output amplifier. The amount of deflection is recorded in the measurement amplifier 35 by 48. The laser beam 34 from the laser displacement meter 33 is applied to the central portion of the substrate 16 that is most bent. Further, although the resistance value of the solder joint portion 37 is increased by a crack generated in the solder joint portion 37 of the substrate 16 due to the drop impact, the resistance value of the solder joint portion 37 is recorded in the measurement amplifier 35 by the strain amplifier 46.
[0027]
As is clear from the above description, in this embodiment, the amount of distortion and deflection of the substrate 16 due to the drop impact and the increment of the resistance value of the solder joint 37 can be measured. Can be measured quantitatively. Further, by repeating the drop impact on the same substrate 16 and the measurement of the resistance value of the solder joint portion 37, the relationship between the number of drop impacts and the increase in the resistance value of the solder joint portion 37 is known, and the drop impact is caused. The lifetime of the solder joint portion 37 can be predicted.
[0028]
Moreover, the drop impact can be measured directly only from the substrate 16, and it is not necessary to apply the drop impact to an electronic device as a product in which the substrate 16 is incorporated and indirectly measure the drop impact from the operation. . For this reason, it is possible to perform measurement on a large number of substrates 16 while suppressing an increase in measurement cost, and it is possible to measure an accurate drop impact with little variation due to the substrates 16.
[0029]
In the above embodiment, the invention of the present application is applied to the drop impact measuring method and the drop impact measuring apparatus for the substrate 16 on which components are mounted and to be incorporated in an electronic device. It is also possible to measure the drop impact of an article other than a portable electronic device or a substrate as a measurement object.
[0030]
【The invention's effect】
In the drop impact measuring method according to claim 1, it is possible to quantitatively measure the amount of distortion and the amount of deflection due to the drop impact received by the measurement object, and moreover, by the accurate drop impact with little variation due to the measurement object. it is possible to measure the strain amount and the bending amount, further, drop impact Runode can measure the object to accurately measure the amount of distortion and deflection amount at the time of receiving the drop impact, the measurement object receives It is easy to consider measures for relaxing the measurement object and preventing the measurement object from being damaged.
[0031]
In the drop impact measuring method according to claim 2, since the influence of the drop impact received by the measurement object can be measured in more detail, the drop impact received by the measurement object is mitigated to prevent the measurement object from being damaged. Therefore, it is easier to think about measures. In addition, it is possible to know the relationship between the number of drop impacts and the increase in the resistance value of the solder joints due to cracks generated in the solder joints of the measurement object due to the drop impacts, so the life of the solder joints due to drop impacts can be increased. Can be predicted.
[0032]
In engaging Ru drop under shock measurement apparatus in claim 3, the strain amount and the bending amount by the drop impact of the measurement object is received can be measured quantitatively, moreover, accurate drop is less variation due to the measurement object impact due can be measured and strain amount and the bending amount, further, Runode can measure the object to accurately measure the amount of distortion and deflection amount at the time of receiving the drop impact, the measurement object receives It is easy to think of measures to mitigate the drop impact and prevent damage to the measurement object.
[0033]
In the drop impact measuring device according to claim 4 , since the influence of the drop impact received by the measurement object can be measured in more detail, the drop impact received by the measurement object is mitigated to prevent the measurement object from being damaged. Therefore, it is easier to think about measures. In addition, it is possible to know the relationship between the number of drop impacts and the increase in the resistance value of the solder joints due to cracks generated in the solder joints of the measurement object due to the drop impacts, so the life of the solder joints due to drop impacts can be increased. Can be predicted .
[Brief description of the drawings]
FIG. 1 is an overall perspective view of an embodiment of the present invention.
FIG. 2 is a plan view showing an electrical connection relationship in a main part of one embodiment.
FIG. 3 is a perspective view of a main part of an embodiment at the moment when a measurement object falls.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Drop impact measuring apparatus, 14 ... Movable part, 16 ... Board | substrate (measurement object), 25 ... Detection part, 33 ... Laser displacement meter (deflection meter), 37 ... Solder junction part, 38 ... Strain gauge (strain meter) 42 ... Strain amplifier (strain meter), 45 ... Variable resistor (resistance meter), 46 ... Strain amplifier (resistance meter), 48 ... Voltage output amplifier (flexometer)

Claims (4)

To the object to be measured with strain gauge affixed to the measuring object with a laser displacement meter in a non-contact state, the measurement object is respectively measured and the strain amount and the amount of deflection when subjected to drop impact A drop impact measuring method comprising the steps.   The drop impact measuring method according to claim 1, further comprising a step of measuring a resistance value of a solder joint portion in the measurement object after the measurement object receives the drop impact. A strain gauge that is attached to a measurement object and measures the amount of distortion when the measurement object is subjected to a drop impact ;
A drop impact measuring device comprising: a laser displacement meter that measures the amount of deflection when the measurement subject is subjected to the drop impact in a non-contact state with the measurement subject . The drop impact measuring apparatus according to claim 3 , further comprising a resistance meter that measures a resistance value of a solder joint portion in the measurement object.

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