JPH0963013A - Fpc structure of magnetic head device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a magnetic head device having an FPC(flexible printed circuit board) structure satisfying an insulation characteristic without impairing the follow-up characteristic of a magnetic head to a medium while maintaining the durability of the FPC to a seek action to the FPC structure of the magnetic head device. SOLUTION: A cover coat 6 on the side for sliding contact with media of a narrow width conductor neck part 8c just before a gimbals juncture 8a of the narrow width conductor neck part 8b successively connected to the gimbals juncture 8a of the FPC 8 is directly deposited on the surface of conductor patterns 3 without via an adhesive layer 4. As a result, the follow-up characteristic of the magnetic head to the surface for sliding contact with media is improved and the modulation characteristics thereof are improved while the durability of the FPC by the seek action is maintained. The electrical shorting of a cartridge to a metallic shutter is prevented and the reliability is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a magnetic head device used for a floppy disk drive (hereinafter abbreviated as FDD) or the like, and particularly to an FPC (flexible printed circuit board) structure thereof.

[0002]

2. Description of the Related Art Recently, along with the trend toward thinner magnetic heads as FDD devices have become thinner (less than 1 inch), the structure of magnetic head devices has a structure on the side opposite to the medium sliding contact surface. ,
The mainstream structure is one that has no protrusions due to electrical connection or the like, that is, has a structure in which the FPC and bobbin terminal are connected between the slider assembly and the gimbal.

A conventional technique will be described below with reference to the drawings. 3 is a side sectional view showing a magnetic head device of Conventional Example 1, FIG. 4 is a side sectional view showing a magnetic head device of Conventional Example 2, and FIG. 5 is a front sectional view showing an AA section of a magnetic head device of Conventional Example 2. , Fig. 6
Is a side sectional view showing a magnetic head device of Conventional Example 3, FIG. 7 is a side sectional view of a magnetic head device of Conventional Example 3 mounted on a carriage, and FIG. 8 is a magnetic head device mounted on a carriage being an FDD device. FIG. 6 is a top view showing a state in which the magnetic head is attached to the magnetic head drive section.

In the magnetic head device 80 of the first conventional example shown in FIG. 3, the FPC 8 is adhesively fixed to the gimbal 11 to which the slider assembly 17 is joined by the double-sided tape 7. The gimbal 11 is made of a thin metal plate such as a stainless steel material or a phosphor bronze material, and has a slit 11a for imparting a spring property for improving the followability of the slider assembly 17 in sliding the medium in the circumferential direction and the diametrical direction. 11b. Slider assembly 1
Reference numeral 7 is a slider made of a ceramic in which a front core 12 of a composite magnetic head including a read / write core (not shown) capable of writing and reading and an erase core (not shown) for erasing both sides of a track is integrally formed. 13 is fused and bonded with glass (not shown), and has a main sliding contact surface 13a and an auxiliary sliding contact surface 13b which are in sliding contact with the medium.

A coil bobbin 15 around which a coil 14 is wound is inserted and fixed to the front core 12, and a back core 16 for forming a magnetic closed circuit of a read / write core and an erase core is embedded in the coil bobbin 15. . Further, the coil bobbin 15 is provided with a number of bobbin terminals 9 corresponding to the land portions 3a for connecting to the plurality of land portions 3a of the FPC 8, and these bobbin terminals 9 are provided.
And the land portion 3a of the FPC 8 are electrically connected by the solder 10.

The FPC 8 is composed of a gimbal connection portion 8a for connecting to the gimbal 11 and a narrow conductor portion 8b which is distant from the gimbal 11 and reaches the control circuit board (shown in FIG. 8) and in which the conductor pattern 3 is narrow and dense. . The conductor pattern 3 and the land portion 3a have a polyimide resin thickness of about 1
Approximately 20 μm thick, which is adhered to the 2 μm base film 1 with the adhesive layer 2 of epoxy resin having a thickness of approximately 15 to 25 μm.
Of the copper foil, a cover film 5 of a polyimide resin having a thickness of about 25 μm is adhered on the conductor pattern 3 via an adhesive layer 4 of an epoxy resin having a thickness of about 20 to 30 μm, and the land portion 3a is Since the bobbin terminal 9 and the solder 10 are electrically connected, the cover film 5 is not attached.

Next, in the magnetic head device 80 of the second conventional example shown in FIGS. 4 and 5, the structure of the slider assembly 17 is the same as that of the first conventional example described above, and therefore the description thereof is omitted and only the configuration of the FPC 8 will be described. The polyimide resin base film 1 is on the medium sliding contact side, and the narrow conductor portion 8b has a narrow conductor neck portion 8c. The structure of the narrow conductor neck portion 8c is such that the cover film 5 and the adhesive layer 4 on the upper surface of the conductor pattern 3 are removed, and the exposed exposed portion of the conductor pattern 3 is solder-plated 18 for rust prevention. The length is about 10 to 30 mm from the end of the gimbal connecting portion 8a on the FPC 8 side toward the narrow conductor portion 8b.

Further, as with the narrow conductor portion 8b, the land portion 3a of the gimbal connecting portion 8a on which the solder plating 18 is applied is
Since it is formed on the side opposite to the medium sliding contact surface, the land bending portion 3b having a bending angle of about 180 ° for connecting with the bobbin terminal 9 is formed.
Having. The land bent portion 3b and the bobbin terminal 9 are electrically connected by the solder 10. At this time, land bending part 3
A gap 19 is formed by b.

The land bent portion 3b is desired to be bent as little as possible in order to prevent damage at the time of bending. Therefore, as shown in the figure, the gimbal 1
The gap 19 between the slider 1 and the slider 13 becomes thicker by the total thickness of the land bending portion 3b.

Next, the magnetic head device 8 of the third conventional example shown in FIG.
In the configuration of 0, the configuration other than the narrow conductor neck portion 8c of the FPC 8 is the same as that of the conventional example 1, and the description thereof will be omitted. The cover film 5 of the narrow conductor neck portion 8c is removed together with the adhesive layer 4, and the exposed conductor pattern 3 is subjected to solder plating 18 for rust prevention.

FIG. 7 is a sectional view of the FDD showing a state in which the above magnetic head devices are incorporated in a carriage assembly and a floppy disk (hereinafter abbreviated as FD) is inserted. The slider assembly 17 (the distinction between the upper and lower slider assemblies is omitted) is fixed to the upper carriage 23 and the lower carriage 24 via the gimbal 11. At that time, the FPC 8 is fixed to the carriages 23 and 24 by the FPC fixing portions 23c and 24c by forming the slack portion 8d at the narrow conductor neck portion 8c. Further, since the slack portion 8d moves up and down in accordance with the vibration of the carriages 23 and 24 during the seek operation, which will be described later, the slack portion 8d slackens toward the medium sliding contact surface side or slackens toward the medium sliding contact surface side. To do.

Until the medium 20 stored in the cartridge 21 is inserted into the carriage assembly 25, the medium 20 is located at the carriage positions 23a and 24a, respectively, where the recording, reproducing and erasing of the medium 20 is performed. A portion of the slider assembly 17 that comes into contact with the main sliding contact surface 13a and its periphery are covered with a metal shutter 22 that is slidably connected to the outer periphery of the cartridge 21, and dirt or scratches on the surface of the medium 20 due to dust or grease. Protects against sticking.

After that, when the cartridge 21 is inserted into the carriage assembly 25 and the medium 20 comes to a fixed position, the metal shutter 22 of the cartridge 21 slides to expose the medium surface, and at the same time, the carriages 23 and 24 move to the carriage position 23b. , 24b, and the main sliding contact surface 13a including the medium sliding contact surface of the front core 12 of the upper and lower slider assemblies 17.
And the auxiliary sliding contact surface 13b sandwich and contact the rotating medium 20, and the carriage assembly 25 moves in the seek direction 34.
By performing a seek operation in the (diameter direction of the medium 20), the medium sliding contact surface of the front core 12 moves to a desired position on the medium 20, and data recording, reproduction, or erasing is performed.

FIG. 8 shows a connecting portion of the drive unit and the FPC on the control circuit board side for performing the above-mentioned seek operation. Upper carriage 23 of the above-mentioned carriage assembly 25
Is connected and fixed to a carriage support plate 29, and the carriage support plate 29 is fixed to a moving unit 36 by screws 35. The moving unit 36 linearly moves in the seek direction 34 by the feed screw 37 and the support shaft 31 which rotate and slide via the gears 27 and 28 which are rotationally driven by the motor 26, whereby the seek operation of the carriage assembly 25 is performed. . Further, in FIG. 7 described above, the carriage 23 located at the carriage position 23b is moved by the spring force of the spring 30 to the carriage support plate 29 during recording, reproduction and erasing.
It is returned to the carriage position 23a via.

On the other hand, a connection terminal portion 8e is provided on the side of the control circuit board 33 opposite to the gimbal connection portion 8a of the FPC 8.
Is formed and is inserted and fixed in the socket 32a of the terminal connecting portion 32 formed on the upper surface of the control circuit board 33. As a result, the narrow conductor portion 8b of the FPC 8 forms the arcuate portion 8f. Therefore, during the seek operation described above, the arcuate portion 8f flexibly operates between the control circuit board 33 and the moving unit 36, so that the electrical connection between the magnetic head device 80 and the control circuit board 33 is maintained for a long time. Has been maintained throughout. This seek operation is an operation that is frequently performed while the carriage assembly 25 is in operation. Further, in order to explain the flexibility by the FPC structure described later, if the relationship of the curvature between the arcuate portion 8f and the slack portion 8d is described, the curvature of the slack portion 8d is more than the curvature of the arcuate portion 8f. Is often set small by design.

Next, the operation of each FPC structure described above will be described. In the configuration of Conventional Example 1, in the durability of the FPC 8 against frequent seek operations (breakage of the conductor pattern 3 and breakage of the FPC 8), the base film 1 and the cover film 5 of the FPC 8 have insulation, heat resistance, and flexibility. Adhesive layers 2, 4 made of high polyimide resin
Is an epoxy resin and has a thickness almost equal to that of the above-mentioned polyimide resin, the durability of the above-mentioned arcuate portion 8f is the best.

However, with respect to the slack portion 8d of the narrow conductor portion 8b adjacent to the gimbal connecting portion 8a, the pressing force to the gimbal 11 by the elastic force of the slack portion 8d is applied by the slits 11a and 11b of the gimbal 11. It becomes stronger than the spring property, and impedes the followability of the medium sliding on the medium sliding contact surface of the slider assembly 17 in the circumferential direction and the diametrical direction. This is particularly remarkable when the curvature of the slack portion 8d is set smaller than the curvature of the arcuate portion 8f. When the followability deteriorates, the levelness between the medium sliding contact surface (the main sliding contact surface 13a and the auxiliary sliding contact surface 13b) of the slider assembly 17 and the medium surface is disturbed, and an error occurs when recording or reproducing a signal. Or worsen the modulation characteristic (stability of the level of the reproduction signal).

Although not described in the conventional example, when the conductor pattern 3 and the cover film 5 are directly adhered without an adhesive layer, for example, the conductor pattern 3 is printed on the upper surface of the base film 1 by a printing method. It is conceivable that the cover film 5 is attached to the upper surface of the conductor pattern 3 by coating. In this case, the flexibility becomes extremely soft, but most of the bending stress applied to the arcuate portion 8f during the seek operation is applied to the conductor pattern 3, which causes the disconnection of the conductor pattern 3 earlier and shortens the durability. A problem arises.

Therefore, in the structure of Conventional Example 2, since the cover film 5 and the adhesive layer 4 are removed only in the narrow conductor neck portion 8c, the flexibility of the narrow conductor neck portion 8c is increased, and the slack portion 8d reaches the gimbal 11. The pressing force of does not impede the spring property for improving the followability of the slits 11a and 11b of the gimbal 11 to the medium surface of the magnetic head, and furthermore, the FPC
Since No. 8 is fixed to the carriages 23 and 24, it is realized without affecting the arcuate portion 8f of the FPC 8 with respect to the seek operation. In addition, since the base film 1 is on the medium sliding contact side, the insulation of the carrier 21 from the metal shutter 22 is sufficient. In addition, in the configuration of the conventional example 3, the cover film 5 and the adhesive layer 4 of the narrow conductor neck portion 8c are removed similarly to the conventional example 2, and thus there is a similar effect regarding flexibility.

[0020]

However, in the conventional example 2, since the base film 1 is on the medium sliding contact side, as described above, the bobbin terminal 9 and the land portion 3 of the FPC 8 are formed.
Since the land bent portion 3b must be formed by soldering with a, the distance between the slider assembly 17 and the gimbal 11 is increased by the total thickness of the land bent portion 3b, and the total thickness of the magnetic head device is increased. Therefore, the structure is disadvantageous for thinning.

Further, the portion which becomes the land bent portion 3b is formed by FP.
It has to be formed so as to project from the gimbal connection portion 8a of C8, and has a different shape in forming the conductor portion including the conductor pattern 3 and the land portion 3a of the FPC 8, so that workability is poor and handling is difficult. Not only does this occur, but since the land bent portion 3b is configured to sandwich the gimbal 11, the work of bending the conductor portion must be performed after connecting the FPC 8 to the gimbal 11, which increases man-hours and work. At times, there is a risk that the land bent portion 3b will be broken.

The conventional example 3 is different from the conventional example 2 in that
The above problem is solved by arranging the base film 1 on the side opposite to the medium sliding contact surface and directly connecting the land portion 3a to the bobbin terminal 9 by soldering. However, the solder plating 1 of the narrow conductor neck portion 8c for giving flexibility to the FPC 1
Since the conductor pattern 3 provided with 8 faces the medium sliding contact surface side without the insulating cover film, the carriages 23 and 24 are moved to the carriage positions 23a and 24a as shown in FIG.
When moving from the carriage positions 23b and 24b to the carriage positions 23b and 24b, the vibration causes the slack portion 8d of the FPC 8 to move up and down to come into contact with the metal shutter 22 located opposite to the slack portion 8d.

As a result, the conductor pattern 3 of the FPC 8,
Alternatively, the bobbin terminal 9 is electrically short-circuited, which not only induces a signal recording / reproducing error and an erasing error in the medium 20, but may damage the coil 14 housed in the slider assembly 17.

An object of the present invention is to solve the above-mentioned problems, and is different from the conventional FPC structure of the magnetic head device.
To provide a magnetic head device having an FPC with a coating structure that maintains the durability of the FPC with respect to a seek operation, does not impair the followability of the magnetic head with respect to the medium, satisfies the insulating property, and is inexpensive and highly productive. is there.

[0025]

SUMMARY OF THE INVENTION To achieve the above object, the gist of the present invention is that, of narrow conductor portions connected to a gimbal connecting portion of an FPC, medium sliding contact of a narrow conductor neck portion immediately before the gimbal connecting portion is achieved. The surface side cover coat material is directly applied to the conductor surface without an adhesive layer.

Further, the cover coat material is characterized by being any one of a polyimide resin, an acrylic paint, an epoxy resin and a silicon resin.

Further, the cover coat material of at least one of the both ends of the cover coat material of the narrow conductor neck is covered with the cover film so as to overlap.

[0028]

According to the present invention, with respect to the arcuate portion of the FPC between the carriage and the circuit board, while maintaining durability against bending stress applied to the arcuate portion by the seek operation of the magnetic head device including the carriage, the FPC is maintained. The portion just before the gimbal connecting portion, that is, the narrow conductor neck portion, does not impede the followability imparted by the gimbal to the diametrical direction and the circumferential direction of the medium sliding contact surface of the magnetic head and the medium surface. The flexibility is obtained, and the insulation of the narrow conductor neck portion with respect to the metal shutter can be secured.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The FPC structure of a magnetic head device according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the FP of the embodiment.
Sectional drawing which shows C structure. FIG. 2 is a top view showing the FPC structure of the embodiment. 1 and 2, the portions other than the FPC structure are the same as the conventional ones, and therefore the description thereof is omitted. FPC8
Comprises a gimbal connecting portion 8a, a narrow conductor portion 8b and a narrow conductor neck portion 8c. Thickness of polyimide resin about 12μm
Of the base film 1 is on the side opposite to the medium sliding contact surface as viewed from the conductor pattern 3, and the conductor pattern 3 and the land portion 3a having a thickness of about 20 μm have an epoxy resin thickness of about 15 to 25 μm.
The adhesive layer 2 of m is attached to the medium sliding contact surface side of the base film 1. Of the narrow conductor portion 8b, about 10 to 10 from the end portion 8g of the gimbal connection portion 8a toward the connection terminal portion 8e (see FIG. 8).
A cover film 5 is attached to a portion reaching the connection terminal portion 8e starting from a portion separated by 30 mm with an adhesive layer 4 of epoxy resin having a thickness of about 15 to 25 μm.

After that, the connection terminal portion 8 starts from the end portion 8g.
A portion of about 10 to 30 mm in the e direction, that is, a narrow conductor neck portion 8
c and the portion of the gimbal connecting portion 8a other than the land portion 3a is made of any one of polyimide resin, acrylic paint, epoxy resin and silicon resin on the conductor pattern 3 and has a thickness of about 20 to 30 μm. After applying by brush coating or printing, the cover coat 6 is formed by drying or baking. Further, among the end portions of the cover coat 6, the end portion on the side of the cover film 5 forms a polymerized portion 8e having a length of about 1 to 5 mm which overlaps with the cover film 5. in this case,
Although the cover coat 6 is formed on the upper surface of the cover film 5, the cover coat 6 may be first formed on the conductor pattern 3 and then the cover film 5 may be attached via the adhesive layer 4.

[0031]

As described above, according to the present invention, the cover coat material on the medium sliding contact surface side of the narrow conductor neck portion immediately before the gimbal connection portion among the narrow conductor portions connected to the gimbal connection portion of the FPC is By directly adhering to the conductor surface without an adhesive layer, the flexibility of only the narrow conductor neck of the FPC can be increased while maintaining the durability of the arcuate portion on the circuit board side of the FPC due to the seek operation. Therefore, it is possible to maintain the horizontality of the medium sliding contact surface of the slider assembly provided by the slit of the gimbal with respect to the medium surface, and the followability becomes good, so that the modulation characteristic is good.

Further, since the land portion can be formed on the medium sliding contact surface side, disconnection of the land portion due to bending can be prevented, and the thickness of the solder connection portion with the bobbin terminal can be made thin. In particular, it is advantageous for a demand for thinning, which does not allow a thickness space, such as a magnetic head device used for an FDD having a thickness of 1 inch or less. Further, since the work of bending the land portion is unnecessary, not only the number of steps can be suppressed and the cost can be reduced, but also an electrical short circuit with the metal shutter of the FD cartridge can be completely prevented, so that the reliability is improved.

Furthermore, since the cover coat material is a polyimide resin, an acrylic paint, an epoxy resin, or a silicon resin, by setting the thickness to an appropriate value, the insulation, flexibility and durability are particularly good. Further, since the cover film and the cover coat of the narrow conductor neck portion are overlapped and covered, the airtightness of the overlapped portion can be increased and the durability including insulation and weather resistance can be improved. . Furthermore, since the cover coat has a structure that can be formed during the FPC forming process, it has various effects such as reduction in manufacturing cost.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an FPC structure of a magnetic head device of the present invention.

FIG. 2 is a top view showing the FPC structure of the magnetic head device of the present invention.

FIG. 3 is a side sectional view showing an FPC structure of a conventional magnetic head device.

FIG. 4 is a side sectional view showing an FPC structure of a conventional magnetic head device.

5 is a front sectional view showing an FPC structure of the conventional magnetic head device of FIG.

FIG. 6 is a side sectional view showing an FPC structure of a conventional magnetic head device.

FIG. 7 is a side sectional view showing a state in which an FD is inserted into a carriage assembly incorporating a magnetic head device.

FIG. 8 is a top view showing a state where the carriage assembly is incorporated in a drive device.

[Explanation of symbols]

 1 Base Film 2, 4 Adhesive Layer 3 Conductor Pattern 5 Cover Film 6 Cover Coat 8 FPC 8a Gimbal Connection 8b Narrow Conductor 8c Narrow Conductor Neck 8e Overlap 80 Magnetic Head Device

Claims (3)

[Claims] 1. A connection between a gimbal and a slider sliding medium contact surface between an FPC formed by sticking a conductor pattern on a base film and a cover film on the upper surface of the conductor pattern and a bobbin terminal of the slider assembly. In a magnetic head device performed between the FPC and the gimbal connecting portion of the FPC, the cover coating material on the medium sliding contact surface side of the narrow conductor neck portion immediately before the gimbal connecting portion,
An FPC structure for a magnetic head device, characterized in that the FPC structure is directly adhered to a conductor surface without an adhesive layer. 2. The FPC structure for a magnetic head device according to claim 1, wherein the cover coat material is one of a polyimide resin, an acrylic paint, an epoxy resin, and a silicon resin. 3. The cover conductor according to claim 1, wherein at least one end of the both ends of the cover coat material of the narrow conductor neck portion is overlapped and covered with the cover film. FPC structure of magnetic head device.