JPH083889B2 - Composite thin film magnetic head - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a magnetic head for recording and reproducing signals on a rotating flexible magnetic recording disk. The present invention relates to a composite magnetic head capable of recording and reproducing information signals other than image signals such as music.

(Prior Art) As a magnetic recording / reproducing apparatus using a flexible magnetic recording disk as a recording medium, a flexible magnetic recording disk on which an image signal has been recorded in advance is rotated to stop the image signal recorded therein. A still image reproducing device that reproduces an image on a display device such as a television receiver, or an image of a subject obtained through a lens is converted into an electric signal and recorded on a flexible magnetic recording disk to receive a television image as a still image. A so-called electronic still camera device for reproducing on a display device such as a machine has been developed.

In these magnetic recording devices and reproducing devices, an image signal is recorded for one field on one turn of an annular track. A method of reproducing one still image by the image signal of one field is called field recording / reproduction. Also, 2
A method in which one field of the same frame is recorded on each of the two annular tracks, one frame is constituted by the image signals from the two annular tracks, and one still image is reproduced is called frame recording / reproduction. That is, frame recording / reproducing requires twice as many annular tracks as field recording / reproducing, and the number of still images that can be recorded on the flexible magnetic recording disk is halved. Also, these annular tracks are typically 40μ
It is formed in a concentric annular shape with a gap (guard hand) of about m.

(Problems to be Solved by the Invention) By the way, when a still image is displayed on a television receiver or the like, there is a strong demand to simultaneously output voice and music corresponding to an image signal.

In response to the above request, an information signal other than an image signal such as voice is temporally compressed and recorded on a part of an annular track that has been conventionally used for an image signal, and the temporally compressed information is recorded. Although a method of expanding and reproducing based on an audio signal has been proposed, such a method not only causes a disadvantage that the number of image signal tracks is reduced by the number of tracks allocated for information signal recording, but also during reproduction. A device for determining whether the signal recorded on the track is an image signal or another information signal such as audio is required, which makes the device complicated and expensive.

In order to prevent the number of tracks for the image signal from decreasing, the information signal is recorded in the gap separating the annular tracks, so-called guard band, and the information signal and the image signal are recorded so as to form azimuth with each other. A recording method has been proposed by JP-A-61-153803. However, the magnetic head for image signals and the magnetic head for information signals are
Normally, they are provided independently of each other, so it is extremely difficult to ensure good head touches of these magnetic heads at the same time at extremely close positions as described above, and tracking of each magnetic head is highly accurate. However, since a complicated mechanism is required to perform the process, the device becomes complicated, resulting in an increase in size and cost. If magnetic heads for image signals and information signals are provided, the positions of both magnetic heads must be adjusted precisely, and the relative positions of the heads differ slightly from device to device. When the recorded magnetic disk is played back on the other device, so-called tracking is difficult and problems such as a reduction in playback output and S / N ratio occur, and replacement of each head becomes difficult, making it virtually incompatible. There is also a serious problem in practical use such as the origin.

Japanese Patent Application Laid-Open No. 61-129701 discloses an apparatus for recording an information signal in a guard band of an annular track for an image signal by using an integrated magnetic head for an image signal and a magnetic head for an information signal. Have been. However, the magnetic head has serious drawbacks in actual use as described below.

That is, the magnetic head has a structure in which one audio signal magnetic head is sandwiched by a pair of image signal magnetic heads, and both sides of the magnetic pole of the audio signal magnetic head are magnetic poles of the image signal magnetic head. The sides and large areas are in close contact with each other. In the magnetic head having such a structure, the magnetic coupling between adjacent magnetic heads is strong, and each signal magnetic flux leaks to the adjacent magnetic head, which causes noise.
So-called crosstalk occurs remarkably, which causes a problem that the reproduced image is greatly disturbed or noise is generated. Therefore, the integrated magnetic head is completely unsuitable for practical use, and a magnetic head capable of excellently recording and reproducing both image signals and information signals on a flexible magnetic recording disk has not been developed yet. is the current situation.

Therefore, in view of the above problems, the present invention can perform highly accurate tracking without increasing the size of the device, has good head touch, and avoids the inconvenience such as occurrence of crosstalk, and the image signal. An object of the present invention is to provide a magnetic head capable of recording and reproducing both an image signal and an information signal on the same disk without reducing the number of tracks for use.

(Means for Solving Problems) In recent years, as a magnetic head for performing high density recording, an upper magnetic layer, a lower magnetic layer, a conductive layer, and an insulating layer are laminated on a substrate by a thin film, and is a part of the conductive layer. A thin-film magnetic head has been developed in which the front surface of the gap portion held between the upper and lower magnetic layers is brought into sliding contact with the recording medium. As a result of earnest studies to achieve the above-mentioned object, the applicant has decided that both the image signal magnetic head and the information signal magnetic head are of the thin film type, and these magnetic heads are integrated to form a composite thin film. It has been found that there is a possibility that a magnetic head satisfying all the above objects can be obtained with a magnetic head.

The composite thin-film magnetic head of the present invention, which has been derived as a result of further research on a specific structure based on the above findings, has a first magnetic head for recording and reproducing a signal on an annular track on a magnetic recording disk, A second magnetic head for recording / reproducing a signal other than the signal is integrally formed on an annular track adjacent to the annular track so as to overlap the same surface side of the substrate, and the first magnetic head and the first magnetic head are combined. The second magnetic head is a thin-film magnetic head in which upper and lower magnetic layers, an insulating layer, and a conductor layer are formed of thin films, and a front surface of a gap portion held by the upper and lower magnetic layers is brought into sliding contact with the magnetic recording disk. And adjacent to each other in the track width direction by forming an azimuth with each other,
In the magnetic head, the center line in the track width direction of the rear gap part is formed at a position farther from the first magnetic head than the center line in the track width direction of the front gap part. Is.

In addition, in the positional relationship between the two center lines, the "position away from the first magnetic head" means the "position apart in the track width direction".

In the present composite thin film magnetic head, it is needless to say that the second magnetic head may be used as the information signal magnetic head and the first magnetic head may be used as the image signal magnetic head. It may be used for signals or both magnetic heads may be used for information signals. The composite thin-film magnetic head may be a two-track magnetic head that field-records and reproduces an image signal and records and reproduces an information signal such as a sound on a track adjacent to the inner or outer circumference of the image-signal track. Then, a three-track magnetic head for recording / reproducing an image signal using two tracks and recording / reproducing an information signal on an A-track sandwiched between these tracks, or a frame recording / reproducing image signal for two tracks Of the image recording signal track and the four-track magnetic head for recording / reproducing the information signal to / from the track adjacent to the inner or outer circumference of the above two tracks. Further, the fact that the first magnetic head and the second magnetic head are substantially adjacent to each other in the track width direction means that the gap portion on the sliding surface that defines the track width is adjacent to the disk to form the track. The magnetic heads may be displaced in the direction perpendicular to the track width direction.
Further, both magnetic heads may be arranged so that tracks formed adjacently on the disk overlap each other, or a slight gap exists.
In both of the magnetic heads, portions such as a conductor layer apart from the sliding surface may partially overlap each other.

Further, in the present invention, the first magnetic head and the second magnetic head are the magnetic head element portions that are the minimum necessary for performing magnetic recording / reproducing, that is, the upper and lower magnetic layers, the conductor layers, and the upper and lower magnetic layers that are mutually overlapping. It is assumed that it is composed of an insulating layer and the like between the two and does not include a substrate, a protective plate and the like, and that the gap portion of the second magnetic head is formed at a position offset from the center line of the second magnetic head. Has become. The center line of the magnetic head is a line indicated by a chain double-dashed line in FIG. 5, which will be described later, and passes through the center point of the rear connecting window connecting the upper magnetic pole and the lower magnetic pole of the second magnetic head. It is a line perpendicular to the track width direction.

(Function) According to the composite thin-film magnetic head having the above-described configuration, the first magnetic head and the second magnetic head are respectively thin-film magnetic heads, so that both heads are integrated when they are integrated. Azimuths can be easily arranged at positions adjacent to each other in the track width direction, and the composite head having such a structure can significantly reduce crosstalk between the heads. Further, by integrating both heads described above, both heads can perform tracking with high accuracy without requiring a complicated mechanism.
Furthermore, since it is relatively easy to set the relative position of the gap between both heads and the azimuth angle with high accuracy, compatibility can be surely obtained.

Further, in the composite thin film magnetic head having the above structure, in order for both the first magnetic head and the second magnetic head to obtain a good head touch with respect to the magnetic recording disk, the gap portion of the first magnetic head is required. It is necessary that the gap portions of the second magnetic head and the second magnetic head are not only substantially adjacent to each other in the track width direction, but also not greatly separated from each other in the direction perpendicular to the track width. That is, when the gaps of both magnetic heads are greatly separated, both heads individually come into contact with the magnetic disk to generate impact noise, which makes it impossible to obtain a stable head touch. In a thin-film magnetic head, a magnetic layer and a conductor layer normally project behind the gap portion in the track width direction symmetrically with respect to the gap portion, and the first magnetic head and the first magnetic head are arranged so as not to damage these layers. When the two magnetic heads are arranged relatively azimuthally, the gap portion of the first magnetic head and the gap portion of the second magnetic head are largely separated in the direction perpendicular to the track width. On the other hand, the composite thin film magnetic head according to the present invention is
Since the center line in the track width direction of the rear gap part is formed at a position farther from the first magnetic head than the center line in the track width direction of the gap part, the second magnetic head It becomes easy to cut at a position as close as possible to the magnetic head, and the second magnetic head and the first magnetic head can be cut.
It is possible to prevent the gap portions of both magnetic heads from being greatly separated in the direction perpendicular to the track width when the magnetic heads of FIG. The interface (head touch) can be improved.

Embodiments Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a front view showing a sliding surface of a composite thin film magnetic head according to one embodiment of the present invention.

This composite thin film magnetic head 50 forms two image signal magnetic heads (first magnetic heads) 10 and 20, and an azimuth angle θ with these two image signal magnetic heads 10 and 20, and also for image signals. The magnetic heads 10 and 20 have an audio signal magnetic head (second magnetic head) 30 adjacent to the image signal magnetic heads 10 and 20 in the track width Tw direction. 3 above
As will be described in detail later, the two magnetic heads 10, 20, 30 are thin-film magnetic heads formed of thin films, respectively, and are held by the upper magnetic layers 11, 21, 31 and the lower magnetic layers 12, 22, 32, respectively. In addition, the gap portions 13a, 23a, 33a, which are insulating layers, are brought into sliding contact with the flexible magnetic recording disk to record and reproduce images or audio signals.

The composite thin-film magnetic head 50 is a three-track composite thin-film magnetic head that records and reproduces image signals in frames.
As shown in FIG. 2, the flexible magnetic recording disk 60 includes
By the two image signal magnetic heads 10 and 20 of the present magnetic head 50, image signals are recorded on two image signal tracks 61 and 62 one field at a time. An audio signal track 63 is formed by the audio signal magnetic head 30 in the portion that was the guard band. Therefore, according to the composite thin-film magnetic head 50, recording and reproduction of an audio signal are performed without reducing the number of tracks for an image signal. Details of the structure of the composite thin film magnetic head 50 will be described below with reference to FIGS. 3, 4, and 5 based on its manufacturing process.

In manufacturing the composite thin-film magnetic head 50, first, as shown in FIG. 3 (a), two-track image signal magnetic heads 10 and 20 are formed of thin films by a conventionally known method. A method of forming the image signal magnetic head 20 will be described with reference to FIG. 4 which is a sectional view taken along line AA of FIG. 3 (a). First, a substrate 24 made of magnetic ferrite will be described.
The lower magnetic layer 22 is deposited on the sendust alloy by sputtering.

Next, on the lower magnetic layer 22, SiO _{2 as an} insulating material and Cu as a coil material are appropriately formed by a known method,
The insulating layer 23 and the two-layer coil conductor 25 as shown in the drawing are formed by etching or the like. Then, similarly to the lower magnetic layer 22, a sendust alloy is further deposited on these laminated bodies by sputtering or the like to form the upper magnetic layer 21. Further above this Si
The protective layer 26 is formed by O ₂ sputtering. The protective layer 26 is polished and flattened to the position shown by the alternate long and short dash line in FIG. The portion of the insulating layer 23 sandwiched between the upper magnetic layer 21 and the lower magnetic layer 22 becomes the gap portion 23a. Further, the other image signal magnetic head 10 is formed on the same substrate as the image signal magnetic head 20 after the lower magnetic layer 12 is formed integrally with the lower magnetic layer 22.
It is formed by exactly the same process. In this embodiment, the coil conductors 1 of the two image signal magnetic heads 10 and 20 are used.
As shown by the broken line in FIG. 1, the reference numerals 5 and 25 are formed so as to project to both sides of the gap portions 13a and 23a in the track width direction by substantially equal amounts.

On the other hand, the audio signal magnetic head 30 is shown in FIG.
As shown in FIG. 4, the substrate 34 is formed separately from the substrate 24 by the same procedure as the image signal magnetic heads 10 and 20 described above, but the shape and arrangement of each layer are the image signal magnetic head 10 and 20. Different from 20, the gap portion 33a is formed at a position deviated from the center line of the audio signal magnetic head 30 in the track width direction. Details of the structure of the audio signal magnetic head 30 are shown in FIG. 5, which is a schematic plan view of the head.

FIG. 5 shows only the upper magnetic layer 31, the lower magnetic layer 32, and the two-layer coil conductors 35A and 35B provided on the substrate.
The audio signal magnetic head 30 includes an upper magnetic layer 31 and an upper magnetic layer 3.
Part of the lower magnetic layer 32 overlapping with 1, coil conductors 35A, 3
5B and an insulating layer (not shown in FIG. 5) provided between the upper and lower magnetic layers 31, 32, and the length in the track width direction is defined by the coil conductors 35A, 35B. . The position of the gap 3a is defined by the position of the portion (upper end portion in the figure) near the sliding surface of the upper magnetic layer 31. In this embodiment, the upper magnetic layer 31 is formed so as to be biased to one end (right side in the figure) of the audio signal magnetic head in the track width Tw direction, and the coil conductors 35A and 35B are arranged at the other end (in the figure) in the track width direction. Only the left side) is projected. Such an audio signal magnetic head 30 is shown in FIG.
After the protective layer 36 is laminated and flattened on the upper side as shown in FIG. 5, a protective plate 38 made of non-magnetic ferrite is adhered to the protective layer 26 by using an adhesive 37 such as a low melting point glass. It becomes the signal magnetic head block 39. This block 39
Next, the position indicated by the alternate long and short dash line in the figure is cut obliquely with respect to the substrate 34 to form the bonding surface 39a. The angle θ between the joint surface 39a and the substrate 34 determines the relative azimuth angle between the information signal magnetic head 30 and the image signal magnetic head. Magnetic head block for audio signals
After the 39 is further cut and processed as required, the joint surface 39a is placed on the protective layer 26 of the two-track image signal magnetic heads 10, 20 as shown in FIG. 3 (c).
It is adhered by an adhesive 40 such as low melting point glass. The composite thin film magnetic head 50 obtained in this way is completed by subjecting it to swing surface processing as necessary.

Therefore, in the composite thin film magnetic head 50 thus completed, the two image signal magnetic heads 10 and 20 and the audio signal magnetic head 30 both obtain a good head touch to the magnetic recording disk. In the direction perpendicular to the track width direction (L direction in FIG. 3 (c)),
It is necessary to bring the gap portion between the audio signal magnetic head and the image signal magnetic head close to each other. The position of the audio signal magnetic head 30 in the above direction changes according to the cutting position when the cutting surface 39a is created. Therefore, when the cutting position (1) shown by the alternate long and short dash line in FIG. 3 (b) changes to the position (l ') away from the gap 33a as shown by the broken line, the magnetic head 30 for audio signals is integrated when integrated. The magnetic heads 10 and 20 for image signals are arranged at positions further away in the L direction. Since the gap portion 33a is formed at a position deviated from the center line of the head in the toque width direction as described above, the magnetic head 30 for audio signals of the present embodiment has a coil even if the vicinity of the gap portion 33a is cut. The conductor etc. will not be cut. Therefore, the audio signal magnetic head 30 of this embodiment can be closely integrated with the image signal magnetic head in the direction perpendicular to the track width of the image signal magnetic head. Incidentally, the sliding surface 50a of the composite thin-film magnetic head 50 is subjected to a sliding surface processing to make the surface spherical as necessary, but the extent to which the audio signal magnetic head is close to the image signal magnetic head Whether it should be arranged in the above position changes depending on the radius of curvature R of the sliding surface. Generally R
Becomes smaller, it becomes necessary to bring the voice signal magnetic head closer to each other. Therefore, the gap portion of the voice signal magnetic head may be formed so as to be largely deviated from the head center line toward the end portion.

As an example, the magnetic heads 10 and 2 for image signals shown in FIG.
The track width Tw of 0 and the track width Tw ′ of the audio signal magnetic head 30 are both 60 μm, and each gap portion 13
The thickness of a, 23a, 33a is 0.3 μm, the gap between the two magnetic heads for image signals 13a, 23a is 40 μm, the azimuth angle θ is 45 °, and the spherical shape is applied. The curvature of the sliding surface is R = 17 and the radius on the sliding surface is 100
Using a composite thin film magnetic head in which the magnetic heads are integrated so that the gaps of all the magnetic heads are within a circle of μm, an image signal and 10 are recorded on the flexible magnetic recording disk rotating at 3600 rpm. Recording and reproduction of an audio signal for 2 seconds were performed. FIG. 6 is a block diagram showing a circuit for recording / reproducing image signals and audio signals by the composite thin film magnetic head 50.

After the color signals of the still image obtained from the imaging system 70 are modulated and added by the FM modulators 71A and 71B, they are passed through the gate 72, and the image signal magnetic heads 10 and 10 in the three-track composite thin film magnetic head 50 are provided. 20 is recorded on the magnetic recording disk 60. On the other hand, after the audio signal obtained from the microphone 80 is amplified by the amplifier 81, the time axis compression circuit 82
Seconds, and the compressed audio signal is
Magnetic head for audio signal in composite thin film magnetic head 50
The data is recorded on the audio signal track of the magnetic recording disk 60 by the 30. Also, when playing audio signals,
The audio signal recorded on the magnetic recording disk 60 is also detected by the information signal magnetic head 30, amplified by the amplifier 84, FM demodulated by the FM demodulator 85, and restored by the time axis expansion circuit 86 for the original 10 seconds. The audio signal is restored. The restored audio signal is output as an audio signal through the amplifier 87. The image signal recorded on the magnetic recording disk 60 is also detected by the image signal magnetic heads 10 and 20, and displayed as a still image on a display device such as a television receiver by a well-known reproducing system (not shown). . During reproduction of this still image, interference from the audio signal, that is, crosstalk, was -44 dB, and no image disturbance was observed. On the contrary, no noise from the image signal was observed at the time of voice reproduction. Furthermore, no impact noise was generated at all and a good head touch was secured for each magnetic head.

As described above, according to the composite thin film magnetic head of the present invention, the magnetic head for image signals and the magnetic head for audio signals are both thin film magnetic heads, so that both magnetic heads are adjacent to each other in the track width direction and azimuth is mutually reduced. It can be easily and integrally formed. Therefore, each magnetic head can perform highly accurate tracking and prevent an increase in crosstalk.
Further, since the gap portion of the audio signal magnetic head is formed at a position deviated from the center line in the track width direction, the audio signal magnetic head can be arranged close to the image signal magnetic head. The magnetic head can stably obtain a good head touch.

Although the three-track composite thin-film magnetic head has been described above as an example, the composite thin-film magnetic head of the present invention is the seventh
As shown in FIG. 3A, a two-track composite thin film magnetic head having a one-track image signal magnetic head 110 and a one-track audio signal magnetic head 130 which are adjacent to each other with an azimuth angle. May be, Figure 7 (b)
As shown in FIG.
It may be a 4-track magnetic head having 220 and 2-track audio signal magnetic heads 230 and 240. 4
In the case of the composite thin-film magnetic head of the track, the sound can be recorded twice as long as the composite thin-film magnetic head of the two-track or the three-track, or stereo recording can be performed. Further, the specific material of each layer of each thin film magnetic head constituting the present composite thin film magnetic head is not limited to that shown in the above-mentioned embodiment, and the structure is such that the conductor layer of each magnetic head is one layer. Various modifications can be made such that each substrate is made of a ferromagnetic material so as to function as a lower magnetic layer. The shapes of the conductor layers (coil conductors) and the magnetic layers of the audio signal magnetic head and the positions of the gaps are also within a range in which the audio signal magnetic head can be arranged at a desired position close to the image signal magnetic head. May be set arbitrarily, as long as at least the gap portion is arranged deviated from the center line of the magnetic head in the track width direction. Further, both the magnetic heads for image signals and the magnetic heads for audio signals may have their gaps formed at positions deviated from their respective center lines. In each of the above embodiments, the case where the information signal other than the image signal is an audio signal has been described as an example. However, it goes without saying that the information signal is not limited to the audio signal, and may be music or other various information signals. No. Further, the head of one track is not limited to the one for the image signal and the head of the other track is not limited to the one for the information signal, and the head of any track may be used for the image signal, and the head of any track may be used. It goes without saying that it may be used for information signals other than image signals.

(Effects of the Invention) As described in detail above, according to the composite thin-film magnetic head of the present invention, both the second magnetic head for information signals and the first magnetic head for image signals are formed by the thin-film magnetic head. Since they are formed and integrated by forming azimuth with each other, a complicated structure is not required for tracking, so that there is no inconvenience such as an increase in size of the entire apparatus and an increase in cost. In addition, since each head can be easily formed to have a predetermined azimuth at a predetermined position,
It has excellent compatibility. Furthermore, since both heads form an azimuth, crosstalk can be made sufficiently small, which makes it possible to use the conventional guard band between the image signal tracks as an information signal track. It becomes possible to record and reproduce information signals without reducing the number of tracks, and to reproduce images and sounds with very little noise.

Further, in the present composite thin film magnetic head, in the second magnetic head, the center line in the track width direction of the rear gap part is farther from the first magnetic head than the center line in the track width direction of the front gap part. Since it is formed at the position, it is easy to cut the second magnetic head at a position as close as possible to the first magnetic head, and both magnetic heads are relatively azimuthally formed so as to be vertically moved on the same surface side of the substrate. When the magnetic heads are formed in the same direction, both the magnetic heads can be brought close to each other in the direction perpendicular to the track width direction, and a good head touch can be ensured for any of the magnetic heads.

[Brief description of drawings]

1 is a front view showing a sliding surface of a composite thin film magnetic head according to an embodiment of the present invention, FIG. 2 is a schematic plan view of a flexible magnetic recording disk, and FIGS. 3 (a), 3 (b), (C) is a perspective view for explaining the structure of the composite thin film magnetic head shown in FIG. 1 based on the manufacturing process thereof, FIG. 4 is a sectional view taken along the line AA of FIG. 3 (a), and FIG. FIG. 6 is a schematic plan view of a signal magnetic head, FIG. 6 is a block diagram of a recording / reproducing circuit for image signals and audio signals, and FIGS. 7 (a) and 7 (b) are composite thin film magnetic heads according to another embodiment of the present invention. It is a front view showing a sliding surface. 10,20 …… Magnetic head for image signal 11,21,31 …… Upper magnetic layer 12,22,32 …… Lower magnetic layer 13a, 23a, 33a …… Gap part 30 …… Magnetic head for audio signal 35A, 35B ...... Coil conductor 50 …… Composite thin film magnetic head 60 …… Flexible magnetic recording disk

Claims (1)

[Claims] 1. A first magnetic head for recording / reproducing a signal on an annular track on a magnetic recording disk, and a second magnetic head for recording / reproducing a signal other than the signal on an annular track adjacent to the annular track. Are integrally formed on the same surface of the substrate so as to overlap each other, and the first magnetic head and the second magnetic head are respectively formed of thin films of upper and lower magnetic layers, an insulating layer, and a conductor layer. A thin film magnetic head for slidingly contacting the front surfaces of the gap portions sandwiched by the upper and lower magnetic layers with the magnetic recording disk, and being adjacent to each other in the track width direction with azimuth between them,
In the second magnetic head, the center line in the track width direction of the rear gap part is formed at a position farther from the first magnetic head than the center line in the track width direction of the front gap part. And composite thin film magnetic head.