JP2001284198A - Crack detecting device and method of laminated type ceramic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crack detecting device and method of a laminated type ceramic capacitor, that can accurately detect the cracks of the laminated type ceramic capacitor. SOLUTION: A printed circuit board 12 mounted with a laminated type ceramic capacitor 13 is placed on a bending rest 16, one end of the printed circuit board 12 is fixed by a fixing device 17, at the same time, a force is applied to the other end of the printed circuit board 12, and the printed circuit board 12 is deformed in a projection shape for applying stress to the laminated type ceramic capacitor 13. In this state, an electrical signal is sent to the laminated type ceramic capacitor 13, an output signal that is outputted via the laminated type capacitor 13 is received, and cracks are detected, based on the received signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crack detecting device and a crack detecting method for a multilayer ceramic capacitor.

[0002]

2. Description of the Related Art A multilayer ceramic capacitor is used as one of circuit elements constituting an electric circuit, and is mounted on a printed wiring board for an ID card which requires a reduction in size.

Here, a multilayer ceramic capacitor will be described with reference to FIG. In the multilayer ceramic capacitor, an electrode plate 42 is provided on a ceramic portion 41 in a plurality of layers vertically, and every other electrode plate 42 is commonly connected to left and right connection electrodes 43a and 43b, respectively.

When a multilayer ceramic capacitor having the above-described structure is mounted on a printed wiring board or the like, when an external force is applied to the multilayer ceramic capacitor, the ceramic portion 4 is removed.
1 may crack, causing cracks in the electrode plate 42. If a crack occurs in the electrode plate 42, the multilayer ceramic capacitor will be in a failure state, and the electric circuit including the multilayer ceramic capacitor will not operate normally. Also, depending on the condition of the printed wiring board, cracks in the capacitor may be temporarily closed, causing normal operation,
For this reason, cracks in the multilayer ceramic capacitor may be missed.

Conventionally, as a method of detecting cracks in a multilayer ceramic capacitor, for example, a wireless I
In the case of a multilayer ceramic capacitor mounted on a printed wiring board for a D card, the electric circuit for an ID card on the printed wiring board including the multilayer ceramic capacitor includes:
A method of transmitting a predetermined transmission signal has been performed. When the ID card electric circuit on the printed wiring board receives a signal transmitted from the outside, it sends back a predetermined modulation signal, and this signal is received by an external receiver. In the receiver, the signal received when the multilayer ceramic capacitor is normal,
The presence or absence of a crack is detected by comparing the signal received from the ID card electric circuit.

[0006]

In the conventional method for detecting a crack in a multilayer ceramic capacitor, as described above, a signal is sent to an electric circuit incorporating the multilayer ceramic capacitor so that the multilayer ceramic capacitor operates normally. In this case, the signal sent back when the signal is sent and the signal sent back from the electric circuit are compared, and the presence or absence of a crack is detected from the difference between these two signals. In this method, if the cracks in the multilayer ceramic capacitor are minute, even if there is a crack, the electrode plate may be in a connected state, and no abnormality may be observed in the signal sent back from the electric circuit. Therefore, cracks in the multilayer ceramic capacitor may not be detected correctly.

The present invention solves the above disadvantages,
An object of the present invention is to provide a crack detection device and a crack detection method for a multilayer ceramic capacitor that can reliably detect cracks in the multilayer ceramic capacitor.

[0008]

According to the present invention, there is provided an apparatus for detecting cracks in a multilayer ceramic capacitor, comprising: a printed wiring board on which the multilayer ceramic capacitor is mounted; and a printed circuit board on which the multilayer ceramic capacitor is mounted is convex. And a deforming device for deforming so that

Further, a method for detecting a crack in a multilayer ceramic capacitor according to the present invention includes a first step of fixing a first corner portion of a printed wiring board on which the multilayer ceramic capacitor is mounted, and a bending table on a back surface of the printed wiring board. A second corner that is diagonally located with the first corner in a state where the first corner of the printed wiring board is fixed and a bending table is arranged on the back surface of the printed wiring board. And a third step of applying a force to the portion.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. A substantially rectangular printed wiring board 12 is arranged on a base 11. Printed wiring board 12
A wiring pattern (not shown) for a circuit is formed thereon, and chip components such as a multilayer ceramic capacitor 13, an integrated circuit 14, and a resistor 15 are mounted thereon. For example, an electric circuit for a wireless ID card is provided. It is configured.

On the back side of the printed wiring board 12, for example, a column-shaped bending table 16 is arranged. When a plurality of multilayer ceramic capacitors 13 are mounted on the printed wiring board 12, the bending table 16 is disposed at a position on the back side of as many multilayer ceramic capacitors 13 as possible.

The rectangular printed wiring board 12 has a portion, for example, one corner fixed to the fixing device 17, and at the same time, a pressing device at another corner located diagonally to the fixed corner. A force is applied in the direction of arrow Y in FIG. At this time, the printed wiring board 12 is bent so that, for example, the side on which the multilayer ceramic capacitor 13 and the like are mounted becomes convex about the position where the bending table 16 is arranged.

Also, near the printed wiring board 12,
A transmitter 19 for transmitting a predetermined transmission signal to an electric circuit on the printed wiring board 12 and a receiver 20 for receiving a signal transmitted from the electric circuit and receiving the transmission signal are arranged.

Here, one of the rectangular printed wiring boards 12
Referring to FIG. 2, a state in which one corner is fixed by the fixing device 17 and a force is applied to the other corner when viewed from above the printed wiring board 12 will be described. In FIG. 2, parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and duplicate description will be partially omitted. The fixing device 17 is composed of walls 17a and 17b which extend in the vertical and horizontal directions in the drawing and are orthogonal to each other.
The printed wiring board 1 includes an upper lid 17c that connects between the two walls 17a and 17b.
2 are arranged. In this case, when the four corners of the rectangular printed wiring board 12 are A, B, C, and D, for example, the corner C is fixed to the fixing device 17.

Then, a force Y is applied from the front side to the back side of the drawing at the corner A located on the diagonal line of the corner C. Further, the bending table 16 is located at a position which is lower left with respect to the side including the fixed corner C of the printed wiring board 12, for example, the side 12b, that is, the parallel edge 1 of the printed wiring board 12.
The multilayer ceramic capacitor 13 is disposed at a position inclined with respect to the edges 13 a of the multilayer ceramic capacitor 13. In this case, the printed wiring board 12 is
6 becomes convex, and the corners A and C are bent so as to be lowered, and stress is applied to the multilayer ceramic capacitor 13. The multilayer ceramic capacitor 13 is usually
As described above, the printed wiring board 12 or the multilayer ceramic capacitor 1 has a property of being strong against stress acting in the direction parallel to the edge and weak against stress acting obliquely on the edge.
By applying a stress in the diagonal direction of No. 3, cracks in the multilayer ceramic capacitor 13 are reliably detected.

In the above configuration, a transmission signal is transmitted from the transmitter 19 to an electric circuit on the printed wiring board 12. When the electric circuit on the printed wiring board 12 receives the transmission signal, it sends back a signal modulated with predetermined data, for example, and this signal is received by the receiver 20. In the receiver 20, the signal received when the multilayer ceramic capacitor is normal and the signal received from the electric circuit are compared, and the presence or absence of a crack in the multilayer ceramic capacitor 13 is detected.

With the above configuration, the printed wiring board 12 is bent so that the side on which the electric circuit is formed is convex,
Stress is applied to the multilayer ceramic capacitor 13.
Therefore, even if the cracks in the multilayer ceramic capacitor 13 are minute, the cracks are emphasized, and the electrodes constituting the multilayer ceramic capacitor 13 do not adhere to each other. Therefore, if the multilayer ceramic capacitor 13 has a crack, an abnormality indicating the presence of the crack appears in the signal received by the receiver 20, and the crack is reliably detected.

Further, the printed wiring board 12 is arranged along the inner sides of the orthogonal walls 17a and 17b.
Is arranged, the printed wiring board 12 is stably fixed, and the printed wiring board 12 does not shift when a force is applied.

Thereafter, as shown in FIG. 3, the corner B of the printed wiring board 12 is fixed, a force is applied to the corner D, and the bending table 16 is moved downward to the right with respect to the side 12b to which the printed wiring board 12 is fixed. Place in position. Also in this case, the bending table 16
Are inclined with respect to the parallel edges 12a, 12c of the printed wiring board 12, and at the same time,
3 is also arranged at a position inclined with respect to the edge. With such an arrangement, the presence / absence of a crack in the multilayer ceramic capacitor 13 is detected again in the same manner as described above.

As described above, when the fixing position of the printed wiring board 12 and the position where the force is applied are changed, and the arrangement of the bending table 16 is changed, the two diagonal directions, that is, the corner C and the corner A stress is applied in the direction connecting A and the direction connecting corner B and corner D. Therefore, the presence or absence of a crack in the multilayer ceramic capacitor 13 is reliably detected.

In the above-described embodiment, the bending table 16 is disposed on the back side corresponding to the position where the multilayer ceramic capacitor 13 is mounted. In the case of this configuration, stress is reliably applied to the multilayer ceramic capacitor 13, and the presence or absence of a crack is correctly detected.

In the above embodiment, the printed wiring board 12 is bent to apply stress to the multilayer ceramic capacitor 13. In this case, if the stress applied to the multilayer ceramic capacitor 13 is too large, the multilayer ceramic capacitor 13 may crack. Therefore, the stress applied to the multilayer ceramic capacitor 13 is set within an allowable range.

Further, in the above-described embodiment, an example is described in which the multilayer ceramic capacitor forms an electric circuit for a wireless ID card. However, the present invention is not limited to the wireless type ID card, but is generally applicable to crack detection for a multilayer ceramic capacitor mounted on a printed wiring board. Further, in the present invention, an ID card or the like having a structure for transmitting a transmission signal in response to a received signal has been described. However, it is needless to say that an ID card having a structure having a transmission function can be applied.

As described above, according to the configuration of the present invention,
A crack detecting device for a multilayer ceramic capacitor capable of reliably detecting a crack even when the crack of the multilayer ceramic capacitor is minute is realized.

[0025]

According to the present invention, a crack detecting device and a crack detecting method for a multilayer ceramic capacitor capable of reliably detecting a crack in a multilayer ceramic capacitor can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic structural diagram for explaining an embodiment of the present invention.

FIG. 2 is a schematic structural diagram for explaining an embodiment of the present invention, and is a diagram for explaining a fixing device, a position where a force is applied, and a positional relationship between a bending table 16;

FIG. 3 is a schematic structural diagram for explaining an embodiment of the present invention, and is a diagram for explaining another example of a positional relationship between a fixing device, a force application position, and a bending table 16;

FIG. 4 is a schematic structural diagram for explaining a multilayer ceramic capacitor used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Base 12 ... Printed wiring board 13 ... Laminated ceramic capacitor 14 ... Integrated circuit 15 ... Resistor 16 ... Bending table 17 ... Fixing device 18 ... Pressurizing device 19 ... Transmitter 20 ... Receiver

Claims (9)

[Claims] 1. A multilayer ceramic capacitor comprising: a printed wiring board on which a multilayer ceramic capacitor is mounted; and a deformation device for deforming the printed wiring board so that the side on which the multilayer ceramic capacitor is mounted is convex. Crack detection device. 2. A deforming device for deforming a printed wiring board on which a multilayer ceramic capacitor is mounted so that one side is convex, a transmitting device for sending a predetermined electric signal to the multilayer ceramic capacitor, and the multilayer ceramic capacitor. A crack detecting device for a multilayer ceramic capacitor, comprising: a receiving device for receiving an output signal output via a capacitor. 3. A deforming device for deforming a printed circuit board on which an electric circuit including a multilayer ceramic capacitor is formed in a convex shape, a transmitting device for sending a predetermined electric signal to the electric circuit, and an output from the electric circuit. A crack detector for a multilayer ceramic capacitor, comprising: a receiver for receiving an output signal. 4. The crack detecting device for a multilayer ceramic capacitor according to claim 2, wherein the deformation device deforms the printed wiring board so that the side on which the multilayer ceramic capacitor is mounted is convex. 5. The crack detecting device for a multilayer ceramic capacitor according to claim 1, wherein the deforming device has a bending table disposed on a side of the printed wiring board opposite to a side on which the multilayer ceramic capacitor is mounted. 6. The crack detecting device for a multilayer ceramic capacitor according to claim 5, wherein the bending table is arranged at a position corresponding to a position where the multilayer ceramic capacitor is mounted. 7. A first step of fixing a first corner of a printed wiring board on which a multilayer ceramic capacitor is mounted;
A second step of disposing a bending table on the back surface of the printed wiring board, and fixing a first corner of the printed wiring board, and disposing the bending table on the back surface of the printed wiring board;
Applying a force to the first corner portion and a diagonally located second corner portion. 8. A first step of fixing a first corner of a printed wiring board on which a multilayer ceramic capacitor is mounted;
A second step of disposing a bending table on the back surface of the printed wiring board, and fixing a first corner of the printed wiring board, and disposing the bending table on the back surface of the printed wiring board;
A third step of applying a force to a second corner part diagonally positioned with the first corner part, and fixing a third corner part adjacent to the first corner part of the printed wiring board on which the multilayer ceramic capacitor is mounted. A fourth step, a fifth step of disposing the bending table at a position different from the second step in a relative positional relationship with the printed wiring board, and a fifth step diagonally positioned with the third corner portion. A method for detecting cracks in a multilayer ceramic capacitor, comprising: a sixth step of applying force to four corners. 9. A stack comprising, after the third step and the sixth step, a transmitting step of transmitting an electric signal to an electric circuit including a multilayer ceramic capacitor, and a receiving step of receiving a signal sent back from the electric signal. Crack detection method for ceramic capacitors.