JP6563695B2 - Printed circuit board and refrigerator equipped with the same - Google Patents

Description

  The present invention relates to a printed circuit board, particularly a printed circuit board on which a sensor is mounted, and a refrigerator including the same.

  In a printed circuit board, it is known that when a voltage is applied to an electrode with water adhering to it due to moisture absorption or condensation, a short circuit occurs between adjacent electrodes due to ion migration (also called electrochemical migration). . In order to suppress such a short circuit due to ion migration, Patent Documents 1 and 2 disclose providing a groove between electrodes.

JP-A 61-268090 Japanese Patent Laid-Open No. 01-270289

  However, according to the study by the inventors of the present application, it has been found that ion migration may not be sufficiently suppressed by a conventional method on a printed circuit board for some applications.

  For example, a printed circuit board on which a temperature sensor is mounted is disposed in a refrigerator compartment of a refrigerator. The temperature sensor is exposed to the air in the refrigerator compartment in order to detect the temperature in the refrigerator compartment. Since the temperature and humidity of the air in the refrigerator compartment change abruptly by opening and closing the door, etc., condensation is likely to occur on the printed circuit board disposed in the refrigerator compartment.

  Also, cracks are likely to occur in the flux remaining on the printed circuit board due to repeated rapid temperature changes. Further, the temperature sensor is always energized for temperature control of the refrigerator compartment.

  Under conditions where moisture is present due to condensation and an electric field is applied between the electrodes connected to the temperature sensor, the activator and electrolyte in the flux residue are eluted using moisture adsorbed from the cracks in the flux as a medium. . These components migrate between cracks, and the insulation between the electrodes decreases due to ion migration, and a short circuit due to ion migration is likely to occur.

  Generally, as a temperature sensor for a refrigerator, a thermistor whose electric resistance value changes according to a temperature change is used. When a short circuit occurs between the electrodes of such a temperature sensor due to ion migration, an electrical resistance is inserted in parallel with the temperature sensor, and the detected electrical resistance value becomes small and higher than the actual temperature (or Low temperature). Therefore, the temperature control of the refrigerator compartment cannot be performed correctly. In addition, the occurrence of such a short circuit between the electrodes of the temperature sensor has a problem that the user cannot immediately know. For example, when a short circuit occurs between the electrodes of the LED element, which is a light emitting element, the LED element stops emitting light, so that it is immediately understood that an abnormality has occurred in the LED element. However, in the occurrence of a short circuit between the electrodes of the temperature sensor, a deviation occurs in the temperature detection value, but since the temperature has been detected itself, the operation according to the erroneous temperature detection value is continued, and the occurrence of the short circuit It is difficult to recognize. The temperature sensor abnormality is difficult to recognize until the temperature control is clearly abnormal, such as when the degree of short-circuiting advances and, for example, the food freezes due to being too cold. Therefore, it is desirable that the temperature sensor is less likely to cause a short circuit than other components.

  This invention is made | formed in view of the said subject, The objective is to provide the printed circuit board which prevents generation | occurrence | production of the short circuit between electrodes by ion migration.

  A printed circuit board according to an embodiment of the present invention includes an insulating substrate, and a solderable first electrode and a second electrode provided on one surface of the insulating substrate, and the first electrode and the second electrode A slit penetrating the insulating substrate is formed between the second electrode and a sensor terminal on the first electrode and the second electrode by soldering.

  In one embodiment, the slit may have a shape that divides a straight line connecting an arbitrary position of the first electrode and an arbitrary position of the second electrode.

  In one embodiment, the slit may have a shape surrounding a side of the first electrode facing the second electrode.

  In one embodiment, a flux may be present on at least one of the first electrode and the second electrode.

  In one embodiment, the slit may have a shape extending linearly between the first electrode and the second electrode.

  In one embodiment, the slit may have an arc shape passing between the first electrode and the second electrode.

  In one embodiment, the slit may have an arc shape combining at least one of a curved shape and a linear shape.

  In one embodiment, the slit may have a shape surrounding a substantially half of the periphery of the first electrode.

  In one embodiment, when the straight line perpendicular to the straight line connecting the center of the first electrode and the center of the second electrode and passing through the center of the first electrode is a first straight line, the slit is And a shape extending between the first electrode and the second electrode and extending in the vicinity of the first straight line.

  In one embodiment, the slit may be formed with an interval, and may have a further slit having a shape surrounding a part of the periphery of the first electrode together with the slit.

  In one embodiment, a wiring connected to the first electrode may be provided between the plurality of slits.

  In one embodiment, when the straight line perpendicular to the straight line connecting the center of the first electrode and the center of the second electrode and passing through the center of the first electrode is a first straight line, the further line The slit may have a shape extending in the vicinity of the first straight line.

  In one embodiment, the first electrode may be one of a positive electrode and a negative electrode, and the second electrode may be the other.

  In one embodiment, a connector used for connection with an external device may be connected to the first and second electrodes.

  In an embodiment, the sensor may be a temperature sensor.

  In one embodiment, the slit may be formed by press punching.

  In one embodiment, the substrate may be a rigid substrate.

  In one embodiment, the substrate may be a substrate including at least one of phenol resin, epoxy resin, and glass fiber.

  In one embodiment, a wiring pattern may be formed on a surface of the substrate opposite to the surface on which the sensor is disposed.

  In one embodiment, soldering may be performed from the side of the substrate opposite to the surface on which the sensor is disposed.

  The refrigerator which concerns on embodiment of this invention is a refrigerator which has a printed circuit board in any one of said, and the sensor by which the terminal was mounted by soldering to said 1st electrode and 2nd electrode, Comprising: During operation, a voltage is applied between the terminals of the sensor.

  According to the printed board according to the embodiment of the present invention, a slit penetrating the board is formed between the electrodes. Thereby, the advance of the metal ion melted from the electrode can be effectively prevented, and a short circuit due to ion migration can be prevented.

It is a figure which shows the refrigerator which concerns on embodiment of this invention. It is a figure which shows the operation panel which concerns on embodiment of this invention. (A) is a figure which shows the front surface side of the printed circuit board which concerns on embodiment of this invention, (b) is a figure which shows the back surface side of a printed circuit board. (A) And (b) is a figure which shows the slit formed in the printed circuit board which concerns on embodiment of this invention. (A)-(c) is a figure explaining the mechanism in which the slit which concerns on embodiment of this invention prevents the short circuit by ion migration. It is a figure which shows the slit formed in the printed circuit board which concerns on embodiment of this invention. (A) is a figure which shows the slit formed in the printed circuit board concerning embodiment of this invention, (b) is a figure explaining the mechanism in which a slit prevents the short circuit by ion migration. It is a figure which shows the slit formed in the printed circuit board which concerns on embodiment of this invention. (A) And (b) is a figure which shows the slit formed in the printed circuit board which concerns on embodiment of this invention. It is a figure showing a plurality of slits formed in a printed circuit board concerning an embodiment of the present invention. It is a figure showing a plurality of slits formed in a printed circuit board concerning an embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the embodiment, the same reference numerals are given to the same components, and the description thereof will be omitted when they are duplicated. The following embodiments are illustrative, and the present invention is not limited to the following embodiments.

(Embodiment 1)
FIG. 1 is a diagram illustrating a refrigerator 10 according to an embodiment of the present invention. A refrigerator 10 illustrated in FIG. 1 includes a refrigerator compartment 11, a freezer compartment 12, and a vegetable compartment 13. The refrigerator compartment 11 and the vegetable compartment 13 store foods to be refrigerated and stored, and the freezer compartment 12 stores foods to be stored frozen. Since the basic structure and operation of the refrigerator are known, the description thereof is omitted here.

  The user can open and close the door 14 of the refrigerator compartment 11 to put food in and out of the refrigerator compartment 11. The refrigerating room 11 is provided with an operation panel 15, and the user can operate the operation panel 15 to adjust the temperature in the refrigerator 10, change the operation mode, and the like.

  FIG. 2 is a diagram illustrating the operation panel 15 according to the present embodiment. The operation panel 15 includes knobs 21 and 22 for temperature adjustment and a button 23 for switching the operation mode. The user can set the temperatures in the refrigerator compartment 11 and the freezer compartment 12 by rotating the knobs 21 and 22. Moreover, the operation mode of the refrigerator 10 can be switched by pressing the button 23.

  FIG. 3 is a diagram illustrating the printed circuit board 30 provided on the operation panel 15. The printed circuit board 30 is a printed wiring board on which a sensor is mounted. 3A shows the front surface side of the printed circuit board 30, and FIG. 3B shows the back surface side opposite to the front surface of the printed circuit board 30. The printed circuit board 30 has an insulating substrate 37. The insulating substrate 37 is, for example, a rigid substrate. The insulating substrate 37 includes, for example, at least one of phenol resin, epoxy resin, and glass fiber as its material.

  On the front surface side of the insulating substrate 37, variable resistors 31 and 32 are disposed at positions corresponding to the knobs 21 and 22, and a switch 33 is disposed at a position corresponding to the button 23. A light emitting element 34 is disposed in the vicinity of the switch 33. The light emitting element 34 is, for example, an LED element, and the lighting state changes according to the switching of the operation mode of the refrigerator 10. A temperature sensor 35 and a connector 36 are disposed on the front surface side of the insulating substrate 37. The temperature sensor 35 is a thermistor, for example, and the electric resistance value changes according to a temperature change. A duct that guides the air in the refrigerator compartment 11 to the temperature sensor 35 is provided on the inner wall portion of the refrigerator compartment 11 (FIG. 1), thereby detecting the temperature in the refrigerator compartment 11 using the temperature sensor 35. Can do. The connector 36 is used to connect various components mounted on the printed board 30 as described above to an external device. The external device is, for example, a main control circuit (not shown) of the refrigerator 10. This control circuit controls the operation of a heat pump (not shown) of the refrigerator 10 based on the temperature and operation mode set by the user and the temperature obtained from the temperature sensor 35.

  FIG. 3B shows the back side of the printed circuit board 30 in a state where the printed circuit board 30 shown in FIG. A wiring pattern 41 is provided on the back surface of the insulating substrate 37. On the back surface of the insulating substrate 37, electrodes connected to the terminals of various components arranged on the front surface side are provided. As a material of each electrode, for example, an arbitrary conductive material such as copper or silver is used, and soldering is possible. Terminals of various components on the front surface side of the insulating substrate 37 reach the back surface through through holes formed in the insulating substrate 37 and are electrically connected to corresponding electrodes via solder. In this example, soldering is performed from the back side of the printed circuit board 30.

  The temperature sensor 35 is electrically connected to electrodes 43 and 44 provided on the back surface of the insulating substrate 37. The connector 36 is electrically connected to an electrode group 42 provided on the back surface of the insulating substrate 37. The electrode group 42 is electrically connected to various components via the wiring pattern 41. The electrode group 42 includes electrodes 51 and 52 connected to the electrodes 43 and 44 via the wiring pattern 41. The electrodes 51 and 52 are electrically connected to the temperature sensor 35 via the wiring pattern 41 and the electrodes 43 and 44.

  During the above-described soldering, flux is applied to the back surface of the printed circuit board 30, so that flux remains on each electrode including the electrodes 51 and 52 after soldering. During operation of the refrigerator 10, the temperature sensor 35 is always energized for temperature control of the refrigerator compartment 11. Therefore, a voltage is always applied to the electrodes 51 and 52, and ion migration is likely to occur. In particular, since the distance between the electrodes connected to the connector 36 is narrow, a short circuit due to ion migration is likely to occur. In this embodiment, a slit penetrating the insulating substrate 37 is formed between the electrode 51 and the electrode 52 to prevent a short circuit due to ion migration.

  FIG. 4 is a view showing a slit 61 formed between the electrode 51 and the electrode 52. 4A shows a peripheral portion of the electrodes 51 and 52 on the back surface of the printed circuit board 30, and FIG. 4B is a diagram showing a cross section of the printed circuit board 30 along the electrodes 51 and 52.

  The terminal 36 t of the connector 36 reaches the back surface through a through hole formed in the insulating substrate 37 and is electrically connected to the electrodes 51 and 52 via the solder 45. A slit 61 that penetrates the insulating substrate 37 is formed between the electrode 51 and the electrode 52. The slit 61 can be formed, for example, by performing a stamping process when the printed circuit board 30 is manufactured. The slit 61 can be formed by using laser processing, a water jet method, a sand blast method, or the like.

  The slit 61 has a shape that divides a straight line 70 that connects the electrode 51 and the electrode 52. The straight line 70 is a straight line connecting an arbitrary position of the electrode 51 and an arbitrary position of the electrode 52. The straight line 70 may be, for example, a straight line connecting the upper end of the electrode 51 and the upper end of the electrode 52 in the figure, or a straight line connecting the lower end of the electrode 51 and the lower end of the electrode 52 in the figure. Also good. The slit 61 divides a straight path between the electrode 51 and the electrode 52 where the electric field is increased. In the example of FIG. 4, the slit 61 has a shape extending linearly between the electrode 51 and the electrode 52. Here, a mechanism in which the slit 61 prevents a short circuit due to ion migration will be described. FIG. 5 is a diagram illustrating a mechanism in which the slit 61 prevents a short circuit due to ion migration. In this example, the electrode 51 is a positive electrode and the electrode 52 is a negative electrode. FIG. 5A shows the lines of electric force existing between the electrode 51 and the electrode 52. In the ion migration, the metal ions melted from the electrodes travel along the electric lines of force between the adjacent electrodes, and return to the metal again on the path along the electric lines of force to form a current path. For this reason, if a slit (space) is formed in a direction substantially perpendicular to the lines of electric force between the electrodes, the metal ions cannot jump over the space. Can be prevented.

  The strength of the electric lines of force is the strongest at the shortest distance between the electrodes, and the distance increases with decreasing curvature. FIG. 5B is a diagram showing a slit 61 that passes through the shortest distance portion between the electrode 51 and the electrode 52. Thus, by forming the slit 61 that passes through the shortest distance portion, it is possible to effectively prevent the metal ions from proceeding.

  The electric lines of force also extend in a curved manner around the electrodes. For this reason, if the length of the slit 61 is insufficient, there is a possibility that metal ions travel around the slit 61 to form a current path. For this reason, as shown in FIG.5 (c), it is desirable to make the slit 61 sufficiently long. Thereby, progress of a metal ion can be prevented more effectively.

  In the configuration in which the grooves are provided between the electrodes as in the prior art, the flux remaining on the printed circuit board tends to accumulate in the grooves, cracks of the flux occur due to temperature factors, and when the conditions of moisture and electric field application overlap, the flux component When the metal ions cross over the groove, a short circuit occurs. However, even if a crack occurs in the flux and the flux component is ionized, the slit 61 that penetrates the substrate of this embodiment has a space, so there is no flux that mediates ion migration, and metal Since ions cannot jump over, a short circuit can be effectively prevented.

  Further, when the electrode is located at the peripheral edge of the printed board 30, the slit 61 may reach the end of the printed board 30. FIG. 6 is a view showing the slit 61 extending to the end portion of the printed circuit board 30. When the slit 61 reaches the end of the substrate, the metal ions can no longer travel around the slit 61, so that the progress of the metal ions can be more effectively prevented.

  In addition, as a measure for preventing a short circuit due to ion migration, a moisture-resistant resin coating may be applied to the electrode. However, in general, the resin coating is performed manually by brushing, and the moisture-proofing measure may be insufficient due to uneven application. Even when application unevenness of the moisture-proof resin coating occurs, a short circuit due to ion migration can be prevented by forming the slit 61 in the printed circuit board 30.

  In addition, by forming the slit 61 in the printed circuit board 30, it is possible to eliminate the step of applying the moisture-proof resin coating as described above, and it is possible to reduce man-hours and improve production efficiency. In addition, since a chemical solvent or the like is not used in the formation process of the slit 61, the environment of the manufacturing process can be improved and the material cost can be reduced.

(Embodiment 2)
FIG. 7 is a view showing a slit 61 formed between the electrode 51 and the electrode 52 according to the second embodiment. FIG. 7A shows a peripheral portion of the electrodes 51 and 52 on the back surface of the printed circuit board 30, and FIG. 7B shows electric lines of force existing between the electrode 51 and the electrode 52. The slit 61 of the present embodiment has a shape surrounding the side of the electrode 51 facing the electrode 52. In the example of FIG. 7, the slit 61 has an arc shape that passes between the electrode 51 and the electrode 52 and surrounds approximately half of the periphery of the electrode 51. The end of the slit 61 has a shape extending in the vicinity of a straight line 71 passing through the center of the electrode 51. Here, the straight line 71 is a straight line perpendicular to the straight line 72 connecting the center of the electrode 51 and the center of the electrode 52, and is a straight line passing through the center of the electrode 51. The shape of the slit 61 extending in the vicinity of the straight line 71 is a shape in which the end of the slit 61 does not reach the straight line 71, a shape in which the end of the slit 61 passes the straight line 71, and an end of the slit 61 is the straight line 71. Any of the shapes that coincide with the positions may be used.

  Since the metal ions that have melted from the electrodes travel along the electric lines of force between the adjacent electrodes, the slits 61 are formed so as to surround the paths of the electric lines of force, so that the metal ions can be effectively advanced. It can block and prevent short circuit.

  As described above with reference to FIG. 5C, it is desirable that the slit 61 be sufficiently long. However, since many components are mounted on the printed circuit board 30 and wiring patterns are complicatedly stretched, it may be difficult to form the slit 61 sufficiently long. Even when the slit 61 cannot be made sufficiently long as far as the position away from the electrode 51 as described above, the formation of the slit 61 so as to cover the periphery of the electrode 51 effectively prevents the progression of metal ions. Short circuit can be prevented.

  Since the electric field is very weak in the vicinity of the straight line 71, the end of the slit 61 does not have to reach the straight line 71.

  When the electrodes 51 and 52 are located at the peripheral edge of the printed circuit board 30, the slit 61 is formed so that one end of the slit 61 reaches the end of the printed circuit board 30 and the other end covers the periphery of the electrode 51. Also good. FIG. 8 is a view showing a slit 61 having one end reaching the end of the printed circuit board 30 and the other end covering the periphery of the electrode 51. Such a shape of the slit 61 can effectively prevent the progression of metal ions.

  In the example of FIG. 7, the slit 61 has a curved shape. However, as shown in the example of FIG. 8, the slit 61 may have an arc shape that combines linear shapes, or an arc shape that combines curved shapes and linear shapes. It may be. FIG. 9A is a view showing a slit 61 having a curved shape at the center and a linear shape at the end, and FIG. 9B shows a slit 61 having a straight shape at the center and a curved shape at the end. FIG. Such a shape of the slit 61 can effectively prevent the progression of metal ions. Thus, the arc shape of the slit 61 may be realized by combining at least one of a curved shape and a linear shape.

  The slit 61 of the present embodiment has a shape that covers the periphery of the electrode 51, but may have a shape that covers the electrode 52, or a shape that covers both the electrodes 51 and 52 like an X-shape. Also good.

(Embodiment 3)
FIG. 10 is a diagram illustrating the printed circuit board 30 in which a plurality of slits 61 and 62 according to the third embodiment are formed. Many components are mounted on the printed circuit board 30 and wiring patterns are stretched around in a complicated manner. For this reason, depending on the wiring pattern of the printed circuit board 30, it may be difficult to cover the periphery of the electrode 51 with one slit 61. In this case, by forming a plurality of slits 61 and 62 and arranging the wiring pattern 41 in the space between the slits 61 and 62, it is possible to prevent a short circuit due to ion migration while securing necessary wiring. it can.

  The slit 61 is formed between the electrode 51 and the electrode 52, and the slit 62 is formed at a distance from the slit 61. The slit 62 has a shape extending in the vicinity of a straight line 71 passing through the center of the electrode 51, and surrounds a part of the periphery of the electrode 51 together with the slit 61. A wiring pattern 41 connected to the electrode 51 is disposed between the slit 61 and the slit 62. In this case, by arranging the slits 61 and 62 so that the electric lines of force pass through at least one of the slits 61 and 62, metal ions can be prevented from traveling around the gap between the slit 61 and the slit 62. And short circuit due to ion migration can be prevented.

  Note that three or more slits may be formed. FIG. 11 is a diagram showing the printed circuit board 30 in which three slits 61, 62 and 63 are formed. The slit 63 is formed with a gap from the slit 61. The slit 63 has a shape extending in the vicinity of a straight line 71 passing through the center of the electrode 51, and surrounds a part of the periphery of the electrode 51 together with the slits 61 and 62. A wiring pattern 41 connected to the electrode 51 is disposed between the slit 61 and the slit 63. Also in this case, by arranging the slits 61, 62, and 63 so that the electric lines of force pass through at least one of the slits 61, 62, and 63, the metal ions can be separated into the gap between the slit 61 and the slit 62 and the slit 61 and the slit. It is possible to prevent the vehicle from traveling around the gap 63 and to prevent a short circuit due to ion migration.

  Each of the shapes of the slits 61, 62, and 63 may be a linear shape, a curved shape, or a combination of a linear shape and a curved shape. .

  The embodiments of the present invention have been described above. In Embodiments 1 to 3 described above, slits are formed between electrodes to which sensors such as temperature sensors are connected. However, slits may be formed between electrodes to which components other than sensors are connected. Thereby, also in components other than such a sensor, the short circuit by ion migration can be prevented.

  In addition, the sensor mounted on the printed circuit board according to the embodiment of the present invention is not limited to the temperature sensor, and may be a different type of sensor. For example, the present invention is applicable to many sensors such as a humidity sensor, an illuminance sensor, and a radiation measurement sensor. Further, for example, a sensor installed outdoors is exposed to a harsh environment such as a rapid temperature change or the occurrence of condensation, and the present invention is useful for such a sensor.

  Further, the present invention is not limited to a printed circuit board for mounting a sensor, but can also be applied to printed circuit boards for other uses.

  This specification is disclosing the printed circuit board and refrigerator as described in the following items.

[Item 1]
An insulating substrate;
A solderable first electrode and a second electrode provided on one surface of the insulating substrate;
Have
A slit penetrating the insulating substrate is formed between the first electrode and the second electrode;
A printed circuit board on which sensor terminals can be mounted on the first electrode and the second electrode by soldering.

  According to the printed circuit board described in Item 1, a slit that penetrates the insulating substrate is formed between the electrodes. Thereby, the advance of the metal ion melted from the electrode can be effectively prevented, and a short circuit due to ion migration can be prevented.

[Item 2]
The printed circuit board according to Item 1, wherein the slit has a shape that divides a straight line connecting an arbitrary position of the first electrode and an arbitrary position of the second electrode.

  Thereby, the advance of the metal ion melted from the electrode can be effectively prevented, and a short circuit due to ion migration can be prevented.

[Item 3]
The printed circuit board according to Item 1, wherein the slit has a shape surrounding a side of the first electrode facing the second electrode.

  Thereby, even when it is difficult to form the slit sufficiently long, it is possible to effectively prevent the progress of the metal ions dissolved from the electrodes and to prevent a short circuit due to ion migration.

[Item 4]
4. The printed circuit board according to any one of items 1 to 3, wherein a flux is present on at least one of the first electrode and the second electrode.

  Even under the condition where flux is present in the electrode, it is possible to effectively prevent the progress of metal ions dissolved from the electrode and to prevent a short circuit due to ion migration.

[Item 5]
Item 4. The printed circuit board according to item 1, wherein the slit has a shape extending linearly between the first electrode and the second electrode.

  Thereby, the advance of the metal ion melted from the electrode can be effectively prevented, and a short circuit due to ion migration can be prevented.

[Item 6]
Item 6. The printed circuit board according to item 1 or 5, wherein the slit has an arc shape passing between the first electrode and the second electrode.

  Thereby, even when it is difficult to form the slit sufficiently long, it is possible to effectively prevent the progress of the metal ions dissolved from the electrodes and to prevent a short circuit due to ion migration.

[Item 7]
Item 7. The printed circuit board according to any one of items 1 to 6, wherein the slit has an arc shape combining at least one of a curved shape and a linear shape.

  Thereby, even when it is difficult to form the slit sufficiently long, it is possible to effectively prevent the progress of the metal ions dissolved from the electrodes and to prevent a short circuit due to ion migration.

[Item 8]
8. The printed circuit board according to any one of items 1 to 7, wherein the slit has a shape that surrounds approximately half of the periphery of the first electrode.

  Thereby, even when it is difficult to form the slit sufficiently long, it is possible to effectively prevent the progress of the metal ions dissolved from the electrodes and to prevent a short circuit due to ion migration.

[Item 9]
9. The printed circuit board according to any one of items 1 to 8, wherein a straight line that is perpendicular to a straight line connecting the center of the first electrode and the center of the second electrode, and that passes through the center of the first electrode. When a straight line is formed, the slit has a shape extending between the first electrode and the second electrode and extending in the vicinity of the first straight line.

  Thereby, even when it is difficult to form the slit sufficiently long, it is possible to effectively prevent the progress of the metal ions dissolved from the electrodes and to prevent a short circuit due to ion migration.

[Item 10]
Item 8. The printed circuit board according to any one of Items 1 to 7, further including a slit formed at a distance from the slit and having a shape surrounding a part of the periphery of the first electrode together with the slit.

  Depending on the wiring pattern of the printed circuit board, it may be difficult to cover the periphery of the electrode with one slit. In this case, by forming a plurality of slits and arranging a wiring pattern in a space between the slits, a short circuit due to ion migration can be prevented while securing necessary wiring.

[Item 11]
Item 10. The printed circuit board according to Item 10, wherein a wiring connected to the first electrode is provided between the plurality of slits.

  Even when it is difficult to cover the periphery of the electrode with one slit, by arranging the wiring pattern in the space between the plurality of slits, a short circuit due to ion migration can be prevented while securing necessary wiring. .

[Item 12]
Item 12. The printed circuit board according to Item 10 or 11, wherein a straight line that is perpendicular to a straight line connecting the center of the first electrode and the center of the second electrode and that passes through the center of the first electrode is a first straight line. Then, the further slit has a shape extending in the vicinity of the first straight line.

  Even when it is difficult to cover the periphery of the electrode with one slit, by arranging the wiring pattern in the space between the plurality of slits, a short circuit due to ion migration can be prevented while securing necessary wiring. .

[Item 13]
Item 13. The printed circuit board according to any one of Items 1 to 12, wherein the first electrode is one of a positive electrode and a negative electrode, and the second electrode is the other.

  The metal ions that have melted from the electrodes tend to travel along the lines of electric force, but the slits can effectively prevent the metal ions from traveling and prevent short circuits.

[Item 14]
14. The printed circuit board according to any one of items 1 to 13, wherein a connector used for connection with an external device is connected to the first and second electrodes.

  Although the distance between the electrodes connected to the connector is narrow and ion migration is likely to occur, a short circuit due to ion migration can be prevented by forming a slit between the electrodes.

[Item 15]
Item 15. The printed circuit board according to any one of items 1 to 14, wherein the sensor is a temperature sensor.

  Although the temperature sensor is always energized and ion migration is likely to occur, a short circuit due to ion migration can be prevented by forming a slit between the electrodes.

[Item 16]
Item 16. The printed circuit board according to any one of items 1 to 15, wherein the slit is formed by press punching.

  Thereby, a slit can be formed easily.

[Item 17]
Item 17. The printed circuit board according to any one of items 1 to 16, wherein the circuit board is a rigid circuit board.

  In such a printed board, a short circuit due to ion migration can be prevented by forming a slit between the electrodes.

[Item 18]
Item 18. The printed circuit board according to any one of items 1 to 17, wherein the substrate includes at least one of phenol resin, epoxy resin, and glass fiber.

  In such a printed board, a short circuit due to ion migration can be prevented by forming a slit between the electrodes.

[Item 19]
Item 19. The printed circuit board according to any one of items 1 to 18, wherein a wiring pattern is formed on a surface of the substrate opposite to a surface on which the sensor is disposed.

  In such a printed board, a short circuit due to ion migration can be prevented by forming a slit between the electrodes.

[Item 20]
In the printed circuit board according to any one of items 1 to 19, soldering is performed from a surface side opposite to a surface on which the sensor is disposed on the substrate.

  In such a printed board, a short circuit due to ion migration can be prevented by forming a slit between the electrodes.

[Item 21]
The printed circuit board according to any one of items 1 to 20,
A sensor having terminals mounted on the first electrode and the second electrode by soldering;
A refrigerator having
A refrigerator in which a voltage is applied between the terminals of the sensor during operation of the refrigerator.

  Even under conditions in which a voltage is constantly applied between the terminals of the sensor, it is possible to prevent short-circuiting due to ion migration and to detect abnormalities such as temperature in the refrigerator.

  The above description of the embodiment is an exemplification of the present invention and does not limit the present invention. In addition, an embodiment in which the components described in the above embodiment are appropriately combined is possible. The present invention can be modified, replaced, added and omitted within the scope of the claims and the equivalents thereof.

  The present invention is particularly useful in the field of printed circuit boards for sensor mounting.

DESCRIPTION OF SYMBOLS 10 Refrigerator 11 Refrigerated room 12 Freezer room 13 Vegetable room 14 Door 15 Operation panel 21, 22 Knob 23 Button 30 Printed circuit board 31, 32 Variable resistance 33 Switch 34 Light emitting element 35 Temperature sensor 36 Connector 37 Insulating board 41 Wiring pattern 42 Electrode group 43, 44, 51, 52 Electrode 45 Solder 61, 62, 63 Slit

Claims (4)

An insulating substrate;
A solderable first electrode and a second electrode provided on one surface of the insulating substrate;
Have
A first slit penetrating the insulating substrate is formed between the first electrode and the second electrode of the insulating substrate,
The insulating substrate is formed with a gap from the first slit, and a second slit penetrating the insulating substrate is formed,
The first slit has at least one of a linear shape and a curved shape dividing a straight line connecting an arbitrary position of the first electrode and an arbitrary position of the second electrode,
The second slit has a shape surrounding the ambient of the first electrode on the side facing the second electrode with the first slit,
When the straight line that is perpendicular to the straight line connecting the center of the first electrode and the center of the second electrode and that passes through the center of the first electrode is the first straight line, the second slit is the first slit. one end of the second slit as viewed from the first electrode extends towards said first slit so as to overlap the first slit, the other end of the second slit is rectilinear shape Ru extending towards the first straight line And at least one of curved shapes ,
A printed circuit board on which sensor terminals can be mounted on the first electrode and the second electrode by soldering. Wherein between the first slit and the second slit, wiring connected to the first electrode is provided, the printed circuit board according to claim 1. Said on at least one of the first electrode and the second electrode are present flux printed circuit board according to claim 1 or 2. A printed circuit board according to any one of claims 1 to 3 ,
A sensor having terminals mounted on the first electrode and the second electrode by soldering;
A refrigerator having
A refrigerator in which a voltage is applied between the terminals of the sensor during operation of the refrigerator.

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