JP5655202B2 - Magnetic head device - Google Patents

Description

  The present invention relates to a magnetic head device provided with a circuit board on which a magnetic head for reading or writing magnetic data is mounted.

  For example, a magnetic recording medium for recording magnetic data includes a card-like medium such as a credit card, prepaid card, or cash card. For example, magnetic data such as a holder ID is recorded on the magnetic stripe formed on the card-like medium. To read or write magnetic data, the magnetic stripe is contacted or slid against the magnetic head, but the signal output from the magnetic head is a weak signal of several millivolts. Because it is easy to receive, measures against noise are necessary. External noise is noise that enters from the outside of the magnetic head. For example, static noise that is easily generated when the magnetic head is in contact with or sliding on the medium, or electricity that is generated from an electronic component mounted on a circuit board ( Magnetic) waves.

  For example, the magnetic head device described in Patent Document 1 includes a circuit board 1 on which a magnetic head 3 and a recording / reproducing amplifier 5 are mounted, as shown in FIG. A plywood structure with the conductive steel plate 7 is used to ensure rigidity. The conductive steel plate 7 is at ground potential, and the magnetic head 3 is attached to the conductive steel plate 7.

Japanese Patent Laid-Open No. 6-333203 (Specification [0008], FIG. 2)

  However, in the magnetic head device shown in Patent Document 1, when the circuit board is made of a plywood structure with a conductive steel plate for the shielding effect, an additional conductive steel plate is required, resulting in an increase in cost.

  In the magnetic head device disclosed in Patent Document 1, the magnetic head and the recording / reproducing amplifier are arranged on the same surface of the circuit board, so that the magnetic head is affected by external noise generated from the recording / reproducing amplifier. There is a problem that it is easy.

  Furthermore, since the conductive steel plate has a plywood structure with the circuit board, since the adhesion with the circuit board and the magnetic head are mounted on the conductive steel plate, if the adhesion with the magnetic head is not sufficient, the shielding effect will be It will fade.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a magnetic head device which is relatively low cost and hardly affected by external noise.

  In order to solve the above problems, the present invention provides the following.

(1) In a magnetic head device in which a magnetic head is mounted on a circuit board, the magnetic head includes a shield case in which a magnetic core and a coil are housed and an earth terminal is attached , and the circuit board is disposed on the back of the shield case. The circuit board is formed with a solid pattern electrically connected to the shield case by the ground terminal on the surface facing the shield case, and the through hole formed in the circuit board. A plurality of terminal pins that entangle the terminal of the coil of the magnetic head pass through, and the plurality of terminal pins protrude from the circuit board, on the surface of the circuit board opposite to the shield case An electronic component electrically connected to the coil is mounted, and the electronic component is disposed between the plurality of terminal pins. Device.

  According to the present invention, since the shield case is disposed on the side of the circuit board where the solid pattern is formed so as to face the solid pattern, the magnetic core, the coil and the like housed in the shield case are externally provided. It can shield from the generated external noise. Therefore, intrusion of external noise can be prevented, and it becomes difficult to be affected by external noise.

  The circuit board is arranged on the back side of the shield case in a state where the back side of the shield case is covered with the circuit board, or the circuit board is mounted inside the magnetic head so that the circuit board is accommodated in the shield case. Status.

(2) The electronic component is a demodulation IC that processes a magnetic signal output from the magnetic head and a control IC that controls the entire magnetic head device, and at least the demodulation IC is disposed between the plurality of terminal pins. the magnetic head device, wherein are.

  According to the present invention, since the shield case is mounted on one side of the circuit board and the electronic component is mounted on the other side of the circuit board, the positional relationship between the magnetic core constituting the magnetic head and the electronic component is kept away. The influence of external noise generated from electronic components can be suppressed.

  (3) A magnetic head device characterized in that the electronic component is sealed with resin and the color of the resin is opaque so that the electronic component cannot be visually recognized.

  According to the present invention, since the electronic component mounted on the other side of the circuit board is sealed with an opaque resin, an act of stealing a signal from the electronic component is made impossible and security is improved. Can do.

  In the magnetic head device according to the present invention, the magnetic head housed in the shield case can shield from external noise generated outside. As a result, intrusion of external noise can be prevented and it is difficult to be affected by external noise.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a perspective view of a magnetic head device 10 according to an embodiment of the present invention.

  In FIG. 1A, a magnetic head device 10 has a magnetic head 20 mounted on one surface (the lower surface in the drawing) via a circuit board 11 and a magnetic signal on the other surface (the upper surface in the drawing). Electronic components such as a control IC 40 and a demodulation IC 30 constituting a processing (recording / reproducing) circuit are mounted. Also, the other surface of the circuit board 11 is soldered with the terminal pins 21 of the magnetic head 20 protruding, and a signal line 50 connected to the host device 200 (see FIG. 3) is electrically connected. Yes. FIG. 1B is a perspective view showing a state where the surface on which the electronic component such as the control IC 40 is mounted on the circuit board 11 is sealed with an opaque resin 70.

  Next, specific configurations of the magnetic head device 10 and the magnetic head 20 will be described in detail with reference to FIG. FIG. 2 is a cross-sectional view for explaining specific configurations of the magnetic head device 10 and the magnetic head 20 according to the embodiment of the present invention.

  The magnetic head device 10 mainly includes a circuit board 11, a magnetic head 20, a control IC 40, and a demodulation IC 30, and the circuit board 11 includes a magnetic signal processing (recording / reproducing) circuit C on which the control IC 40 and the signal line 50 are mounted. Have. Note that the demodulation IC 30 that processes the output signal from the magnetic head 20 and the control IC 40 that controls the entire magnetic head device 10 are separated from each other depending on the space of the circuit board 11, but may be configured as a single IC. Good.

The circuit board 11 has a solid pattern 12 formed on the surface on which the magnetic head 20 is mounted, and electronic components (for example, a demodulation IC 30 and a control IC 40) and the like are mounted on the opposite side. The circuit board 11 is provided with a pattern wiring of a magnetic signal processing (recording / reproducing) circuit C for processing a magnetic signal output from the magnetic head 20.
In the present embodiment, a solid pattern is formed on a solid portion where the pattern wiring is not formed on the opposite side where the pattern wiring is formed, and is grounded. In this solid pattern, external noise generated mainly from mounted electronic components or the like is caused to flow through the solid pattern.

  In addition, a ground terminal 80 (see FIG. 1) is attached to the shield case 22, and the ground case 80 is electrically connected to the solid pattern 12, so that the shield case 22 and the base pattern 12 are equal to each other. The potential can be maintained. In this way, by setting the solid pattern 12 to the ground potential (frame ground), the charge charged on the shield case 22 can be caused to flow to the solid pattern 12.

  The magnetic head 20 reads or writes magnetic data recorded on a recording medium. As shown in FIG. 2, the magnetic cores 23a and 23b, the core holder 26, the coil 28, etc. are accommodated in the shield case 22. Has been. The back surface of the shield case 22, that is, the surface on which the terminal pins 21 protrude is in contact with the solid pattern 12 formed on the circuit board 11, and the outer peripheral surface thereof is covered with the solid pattern 12 with a conductive adhesive or the like. It is fixed. That is, the back surface of the shield case 22 is blocked by the circuit board 11. Further, since the solid pattern 12 is formed on the circuit board 11, the external noise generated outside the shield case 22 is prevented from entering the magnetic cores 23a, 23b and the like housed in the shield case 22. .

  In the present embodiment, since the solid pattern 12 formed on the circuit board 11 is at the ground potential, the shield electrically connected to the solid pattern 12 even when the magnetic head 20 is charged with static electricity. Since static electricity can be released from the case 22, it is possible to prevent external noise such as static electricity from flowing through the control IC 30 mounted on the circuit board 11.

  Since the magnetic head 20 records and reproduces magnetic information signals while being in contact with and sliding on the magnetic recording medium, static electricity is likely to occur at the time of contact, and this static electricity adversely affects the recording and reproduction signals as external noise. It becomes a problem to give.

  In the present embodiment, the magnetic head 20 is a three-channel magnetic head having three sets of magnetic cores corresponding to three data tracks (also referred to as channels). Specifically, the magnetic head 20 includes three sets of core holders 26, a pair of magnetic cores 23a and 23b held by each core holder 26, and a magnetic shielding plate 29 positioned between the pair of magnetic cores 23a and 23b. The three pairs of magnetic cores 23a and 23b are arranged so as to correspond to the three data tracks and are stored in the shield case 22. The magnetic shielding plate 29 is disposed between three sets of adjacent magnetic cores and shields leakage magnetic flux between the magnetic cores 23. In other words, the magnetic shielding plate 29 blocks the magnetic force leaked from the magnetic gap G formed in each set, and the generation of a magnetic field between the adjacent magnetic cores 23 is suppressed. The pair of magnetic cores 23a and 23b is composed of a laminate of high magnetic permeability magnetic thin plates such as permalloy, and the pair of magnetic cores 23a and 23b are abutted and joined to form a ring shape. The magnetic gap G is formed by interposing a magnetic gap material.

  The resin holder 24 is filled around the core holder 26 and the pair of magnetic cores 23 a and 23 b in the shield case 22, and the tips of the pair of magnetic cores 23 a and 23 b are exposed from the window 25 of the shield case 22. I try to harden. Therefore, the resin 24 is exposed in the window 25 of the shield case 22 so as to surround the three sets of magnetic cores 23. In other words, the three sets of magnetic cores 23 face the magnetic gap G on the sliding surface that is slid on the three data tracks formed on the magnetic recording medium, that is, on the window 25 formed on the upper surface of the shield case 22. Is fixed.

  A coil bobbin 27 is mounted on the rear side of the pair of magnetic cores 23a and 23b, and a predetermined number of turns of a coil 28 through which a recording / reproducing signal current flows is wound around the coil bobbin 27. The coil bobbin 27 obtains insulation between the pair of magnetic cores 23 a and 23 b and the coil 28. The coil bobbin 27 is formed with two terminal pins 21 that tie the ends of the wound coil 28. The back surface of the shield case 22 is the rear surface of the magnetic head 20, that is, the surface on which the terminal pins 21 are projected. In the present embodiment, since the magnetic head 20 is a three-channel magnetic head, as shown in FIG. 1, six terminal pins 21 protrude corresponding to the three sets of magnetic cores 23.

  Further, as shown in FIGS. 1A and 2, each terminal pin 21 passes through a through hole formed in the circuit board 11, and the circuit board 12 is formed on the opposite surface where the solid pattern 12 is not formed. Are soldered and electrically connected to land portions (not shown). The through hole is formed with a diameter having a gap so that the terminal pin 21 does not contact the solid pattern 12.

  The shield case 22 is for protecting the magnetic core 23 and the like from external noise, and a window 25 is provided in a portion that contacts and slides with the magnetic recording medium so that the magnetic core 23 and the like are exposed. As shown in FIG. 1A, the shield case 22 (outer peripheral surface thereof) is provided with a ground terminal 80, and the shield case 22 is grounded by the ground terminal 80. In the present embodiment, the ground terminal 80 is electrically connected to the solid pattern 12 formed on the circuit board 11 and is grounded.

  In the circuit board 11 including the magnetic head 20 and the magnetic signal processing (recording / reproducing) circuit C, the distance between the coil 28 and the magnetic signal processing (recording / reproducing) circuit C is also short, so that external noise is mixed. Will not be affected by external noise

  The three sets of magnetic cores 23 are in contact with each other as described above, and are provided so as to form three magnetic gaps G and magnetic paths. The core holder 26 is preferably constituted by a cast product of a non-magnetic material that can be easily manufactured at low cost, for example, aluminum die cast or zinc die cast, but is not limited thereto.

  FIG. 3 is a block diagram showing an electrical configuration of the magnetic head device 10 according to the embodiment of the present invention.

  In FIG. 3, the magnetic head device 10 according to the embodiment of the present invention mainly includes a magnetic head 20, a control IC 40, and a demodulation IC 30. The demodulating IC 30 includes an AMP circuit 32, a demodulating circuit 33, and an interface unit 34 as circuits for processing a magnetic signal output from the magnetic head 20. The control IC 40 is a circuit that controls the entire magnetic head device 10 and includes a CPU 31, a RAM 35, and a ROM 36. The RAM 35 and / or the ROM 36 may be incorporated in the CPU 31 (built-in ROM or the like). The ROM 36 stores a basic program for the magnetic head device 20 to read the magnetic data recorded on the magnetic recording medium and record the magnetic data on the magnetic recording medium. The RAM 35 is a working of the CPU 31. Functions as an area. The control IC 40 and the demodulation IC 30 may be separate IC chips or may be configured as one chip.

  The CPU 31 manages the control center of the magnetic head device 10 and performs integrated control of the magnetic head device 10. A reproduction signal from the magnetic head 20 is amplified and waveform-shaped in an AMP (amplification) circuit 32 and demodulated in a demodulation circuit 33 (after binarization of a read signal, that is, A / D conversion), RS232C Or the like via the interface unit 34. Note that the demodulation circuit 33 that performs A / D conversion may be included in the CPU 31. The CPU 31 communicates with the host device (PC 200) via an I / F circuit (not shown).

  FIG. 4 is a partial cross-sectional view in which the magnetic head device according to the embodiment of the present invention is mounted on a magnetic card reader.

  The magnetic card reader 1 is a device that reads magnetic data recorded on a magnetic stripe on a card-like magnetic recording medium and records magnetic data on a card-like medium. As shown in FIG. 4, the magnetic card reader 1 is arranged so that a card insertion slot 6a into which a card-like magnetic recording medium (not shown) is inserted and the frames 4 and 4 face each other, and the card-like magnetic recording inserted. A card transport path 6 through which the medium is transported, and a magnetic head for reading the magnetic data of the card-shaped magnetic recording medium disposed and transported in the card transport path 6 and recording the magnetic data on the card-shaped magnetic recording medium transported A device 10 is provided. In the present embodiment, the magnetic card reader 1 is a manual type in which a user manually runs a card-like magnetic recording medium in the card transport path 6 and reads magnetic data recorded on the card-like magnetic recording medium. This is a magnetic card reader.

  As shown in FIGS. 1 and 4, the magnetic head device 10 is fixed to an elastic body such as a leaf spring 60 with an adhesive. A biasing force is applied to the magnetic head device 10 by the elastic force of the leaf spring 60 itself, and the card-like magnetic recording medium is contacted and slid by a predetermined pressing force. In addition, small holes 60 a and 60 b are formed at both ends of the leaf spring 60 with the magnetic head device 10 interposed therebetween.

  As shown in FIG. 4, such a magnetic head device 10 is disposed in the vicinity of the magnetic card insertion slot 6 a of the magnetic card reader 1. The frame 4 of the magnetic card reader 1 is provided with support plates 2a and 2b, and pins 3a and 3b are planted on the support plates 2a and 2b. Small holes 60a and 60b of a leaf spring 60 are fitted into the pins 3a and 3b. A coil spring 5 is inserted into the pin 3b, and the coil spring 5 is urged toward the conveyance path of the card-like recording medium together with one side of the leaf spring 60 to which the magnetic head device 20 is fixed. Energizing force is given. Note that the spring pressure of the coil spring 5 is set to be equal to the elastic force of the leaf spring 60 and maintains a balance with respect to the vertical movement of the magnetic head device 20.

  In the magnetic card reader 1 configured as described above, when the card-like magnetic recording medium is transported in the card transport path 6, the magnetic head device 10 is operated by the elastic force of the leaf spring 60 and the biasing force of the coil spring 5. Then, while applying a predetermined pressing force to the card-like magnetic recording medium, it contacts and slides on the magnetic stripe formed on the card-like magnetic recording medium. The magnetic head device 10 reads or writes magnetic data recorded on the magnetic stripe by the magnetic head 20.

[Main effects of the embodiment]
As described above, according to the magnetic head device 10 according to the present embodiment, the magnetic head 20 is shielded from the entry of external noise from the outside by the solid pattern 12, so that the shielding effect and the countermeasure against external noise are compared with the conventional one. It can be realized at low cost.

  Further, since the circuit board 11 is disposed on the magnetic head 20 as compared with the case where the magnetic head 20 and the circuit board 11 are connected by a copper wire or the like, a wiring pattern from the magnetic head 20 to an electronic component, a copper wire, or the like As a result, the influence of external noise can be suppressed. In addition, since the circuit board 11 is positioned between the magnetic head 20 and the electronic component and the positional relationship between the magnetic head 20 and the electronic component is kept away, the influence of external noise can be suppressed. Furthermore, since the copper wire between the magnetic head 20 and the circuit board 11 is short, high S / N signal exchange can be achieved.

  In addition, when the surface of the circuit board 11 on which the magnetic head 20 is mounted is a solid pattern 12, the solid pattern 12 is set to a ground potential (frame ground), so that the magnetic head 20 is charged with static electricity. In addition, it is difficult for static electricity to fly to the side of the circuit board 11 on which electronic components such as the control IC 40 and the demodulation IC 30 are mounted, and adverse effects of the electronic components due to static electricity can be suppressed.

  Further, since the electronic component mounted on the side opposite to the magnetic head 20 is sealed with an opaque resin 70, it is impossible to specify a signal such as to which electronic component the signal line 50 is connected. By adopting such a configuration, security can be improved.

  Further, by using the magnetic head device 10 for the magnetic card reader 1, it is possible to suppress the influence of external noise and improve security.

  Furthermore, even when the magnetic head 20 is charged with static electricity, the solid pattern 12 is grounded (frame ground), so that it is possible to prevent static electricity from being applied to a weak magnetic signal and to cause a read error. Can be prevented.

  In addition, when writing magnetic data to a magnetic card having a high coercive force, an appropriate write current corresponding to the coercive force, that is, a large current is required, but it is generated from a magnetic core or the like housed in the shield case 22 This external noise can be released from the solid pattern 12. Thereby, it is possible to suppress an adverse effect on the electronic components and the like mounted on the circuit board 11.

[Other embodiments]
5A and 5B are schematic views showing an outline of a magnetic head device 10 'according to another embodiment of the present invention, in which FIG. 5A shows a state in which the tips of the magnetic cores 23a and 23b are exposed, and FIG. 5B shows a shield. FIG. 4 is a diagram showing an internal structure of case 22

  In FIG. 5, three sets of magnetic cores 23a, 23b are provided in the shield case 22, and the magnetic head device 10 'mounts the circuit board 11' on which the solid pattern 12 'is formed inside the magnetic head 20'. Yes. Although the magnetic cores 23a and 23b are not limited to three sets, the magnetic cores 23a and 23b are provided in the shield case 22 so that a shielding effect can be exhibited.

  In such a magnetic head 20 ′ and magnetic signal processing (recording / reproducing) circuit C, the magnetic signal processing circuit C is stored in a shield case 22 of the magnetic head 20 ′, and the shield case 22 is connected to a ground terminal (not shown). In addition, since the distance between the coil wound around the magnetic cores 23a and 23b and the magnetic signal processing circuit C is short, the external noise is less likely to be mixed, and the influence of the external noise is reduced. It becomes difficult to receive.

  In the present embodiment, the magnetic head is a three-channel magnetic head, but is not limited to this. The magnetic head device may be a device that reads or writes magnetic data other than the magnetic card reader.

  The magnetic head device according to the present invention and the magnetic card reader equipped with the magnetic head device are useful as those capable of realizing a shielding effect and noise countermeasure at low cost by a circuit board on which a solid pattern is formed.

1 is a perspective view showing an outline of a magnetic head device according to an embodiment of the present invention. It is explanatory drawing for demonstrating the specific structure of the magnetic head apparatus which concerns on embodiment of this invention, and a magnetic head. 1 is a block diagram showing an electrical configuration of a magnetic head device according to an embodiment of the present invention. 1 is a partial cross-sectional view in which a magnetic head device according to an embodiment of the present invention is mounted on a magnetic card reader. It is a figure which shows the outline | summary of the magnetic head apparatus based on other embodiment of this invention. It is the schematic which shows the outline | summary of the conventional magnetic head apparatus.

DESCRIPTION OF SYMBOLS 1 Magnetic card reader 10, 10 'Magnetic head apparatus 11 Circuit board 12 Solid pattern 20 Magnetic head 21 Head terminal 22 Shield case 30 Demodulation IC
40 Control IC
50 signal line 60 leaf spring 70 resin

Claims (3)

In a magnetic head device in which a magnetic head is mounted on a circuit board,
The magnetic head includes a magnetic core and a coil, and includes a shield case to which a ground terminal is attached , and the circuit board is disposed on the back of the shield case,
In the circuit board, a solid pattern electrically connected to the shield case by the ground terminal is formed on a surface facing the shield case ,
A plurality of terminal pins that entangle a terminal of the coil of the magnetic head pass through a through hole formed in the circuit board, and the plurality of terminal pins protrude from the circuit board,
An electronic component that is electrically connected to the coil is mounted on the surface of the circuit board opposite to the shield case,
The magnetic head device, wherein the electronic component is disposed between the plurality of terminal pins. The electronic component is a demodulation IC that processes a magnetic signal output from the magnetic head and a control IC that controls the entire magnetic head device.
2. The magnetic head device according to claim 1, wherein at least the demodulation IC is arranged between the plurality of terminal pins.   3. The magnetic head device according to claim 1, wherein the electronic component is sealed with a resin, and the color of the resin is opaque so that the electronic component cannot be visually recognized.

Images