JP3098316B2 - Magnetic recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus, a magnetic head thereof, and a method of manufacturing a magnetic head, and more particularly to a high density magnetic recording.

[0002]

2. Description of the Related Art FIG. 11 is an explanatory view of a track pattern in an overwrite recording system used in a VHS system VTR.
In 1, 1 is a first magnetic head which is an audio head;
Reference numeral 2 denotes a second magnetic head which is a video head, 3 denotes a track recorded by the first magnetic head 1, and 4 denotes a track recorded by the second magnetic head 2. next,
The operation will be described. In FIG. 11, after the track 3 is recorded by the first magnetic head 1, the track 4 is recorded by the second magnetic head 2. FIGS. 12A and 12B show the spectrum at this time, and FIG. 12A shows the spectrum of the signal recorded by the first magnetic head 1. FIG. 12B shows a spectrum of a signal recorded by the second magnetic head 2. Also,
The audio signal in FIG. 12A is set to the band having the lowest energy of the spectrum of the video signal shown in FIG.

The center of the signal recorded by the first magnetic head 1 is 1.5 MHz, and the center of the signal recorded by the second magnetic head 2 is 6.5 M in the case of S-VHS.
Hz. Since the relative speed of the tape head is 5.8 m / s, the recording wavelength is 3.6 μm and 0.9 μm, respectively, and the gap length of the head is usually set to か ら to の of the recording wavelength. Therefore, the gap length of the head is different, and the audio head is about 1 μm and the video head is 0.4 μm.
m. The azimuth angle is set to 30 ° for the audio head and 6 ° for the video head.

FIG. 13 is a sectional view of a tape recorded on a tape. In FIG. 13, reference numeral 5 denotes a magnetic tape (magnetic medium).
Is a magnetic layer of a magnetic tape (magnetic medium). d ₁ is the depth recorded by the first magnetic head 1, conveniently referred to this portion and the deep layer track. Further, d ₂ is the depth recorded by the second magnetic head 2, also referred to this portion and surface layer portion truck. In the case of magnetic recording, it is known that the recording depth at which the maximum output is obtained is ４ of the recording wavelength, and d ₁ is about 1 μm and d ₂ is about 0.2 μm.

[0005]

Since the conventional magnetic recording / reproducing apparatus is configured as described above, it is necessary to set two recording signals so that the bands of the recording signals do not overlap as much as possible. It was difficult to record digital signals and the like.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has a magnetic recording / reproducing apparatus capable of recording and reproducing a signal having the same band on the same track by superimposing the signal, and a magnetic head and a magnetic recording / reproducing apparatus. An object of the present invention is to provide a method for manufacturing a magnetic head.

[0007]

Means for Solving the Problems] The magnetic recording and reproducing apparatus is equal track width gap length according to the present invention is equal KuKatsu
A first magnetic head and a second magnetic head having different azimuth angles, and a signal having an equal frequency band when the second magnetic head overlaps recording on a track recorded by the first magnetic head; recorded by the first head and the second head, and equal to the recording current value to obtain a maximum reproduced output recording current value of the first head, the recording electrodeposition of the second head
The current value is the optimum recording current (the recording current value at which the maximum reproduction output is obtained)
0.4 times is obtained by 0.5 times.

[0008]

[0009]

[0010]

[0011]

[0012]

[0013]

According to the present invention, the azimuth angles of the first and second magnetic heads are made different so that no crosstalk occurs between the two signals at the time of reproduction, so that the track recorded by the first magnetic head can be reproduced by the second magnetic head. , The number of tracks can be halved, and the track width of both heads is equalized, so that the S / N ratio can be improved by effectively utilizing the area of the recording medium. Therefore, a plurality of types of digital signals having a wide band can be recorded as they are. Then, over the recording current of the first head equivalent to the recording current value to obtain the maximum playback output at the structure, and recording current of the second head
The value is 0.4 times to 0.4 times of the recording current value at which the maximum reproduction output is obtained.
Since it is five times, the reproduction outputs of the first and second magnetic heads can be made equal, and the S / N imbalance between the reproduction outputs of the respective heads can be prevented.

[0015]

[0016]

[0017]

[0018]

[0019]

[0020]

EXAMPLES The following first embodiment of the first embodiment of the present invention with reference to FIG be described. FIG.
, 1 is a first magnetic head, 2 is a second magnetic head, 3 is a track recorded by the first magnetic head 1 (hereinafter referred to as a deep track), 4 is a track recorded by the second magnetic head 2 (Hereinafter referred to as a surface track) (see FIG. 13).

For example, signals of the same band, such as time-divided digital signals, are recorded and reproduced by the first magnetic head 1 and the second magnetic head 2. In order to record and reproduce signals in the same band, the first magnetic head 1 and the second magnetic head 2 have the same gap length. Also, in order to achieve high density recording,
The track widths of these two magnetic heads are also set equal,
Although one magnetic head is used, the number of tracks is halved by using one track. Furthermore, in the case of signals in the same band, crosstalk becomes a problem between the deep layer and the surface layer. Therefore, the azimuth angles are set to be equal in directions opposite to each other with respect to the head traveling direction.

By obtaining the same signal level from the two heads during reproduction, equivalent recording and reproduction are performed. Curve C in FIG. 3 shows the relationship between the recording strength and the reproduction output. Point A is the point at which the maximum output when recording with the first magnetic head 1 is obtained. This is the same for the second magnetic head 2 which differs only in the azimuth angle. The first magnetic head 1 records up to point A, and the second magnetic head 2 records B.
When the recording is performed up to the point, the curve indicating the reproduction level of the first magnetic head 1 is C ′. Point A 'indicates that the output at point A has dropped to A' when recording is performed up to point B with the second magnetic head 2. Equal the level of level A'point of the point B, it becomes at apparently two magnetic heads that record reproducing the <br/> or the like is performed.

Next, the recording strength at point B is determined. The reason why the output of the signal optimally recorded on the deep track 3 is reduced by the recording of the surface track 4 is that the recorded amount of the surface track 4 has been erased for the deep track 3, so that the spacing between the read head media is reduced. It is thought that the loss increased.

Therefore, the recording depth of the surface track 4 is set to d ₂
If the recording wavelength λ of both tracks is used, the output E ₁ of the deep track 3 is as follows.

E ₁ = Eexp (−2πd ₂ / λ) (1) (where E is a constant) On the other hand, since the output of the surface track 4 does not perform sufficient recording, the reproduction output E ₂ is the thickness of the magnetization. From the relationship between and and the output,

E ₂ = E {1−exp (−2πd ₂ / λ)} (2) (where E is a constant) Here, the condition that E ₁ is equal to E ₂ is as follows.

2exp (−2πd ₂ / λ) = 1 (3) The equation (4) is obtained from the equation (3).

D ₂ = λ / 2π × ln2 = 〜0.11λ (where “= 〜” indicates substantially equal) (4) From this, it is possible to set the surface recording depth d ₂ to 0.11λ. The outputs of the deep track 3 and the surface track 4 can be made equal.

When the surface recording strength d ₂ is 0.11λ, the recording strength in the case of optimum recording is 0.25λ,
It is 0.44 times. Since the recording depth and the recording intensity (recording current) are proportional unless the magnetic saturation of the head occurs, the recording depth of the second magnetic head 2 eventually becomes about 0.4 to 0.5 times the optimum recording. If set, the reproduction output of the first and second magnetic heads 1 and 2 becomes equal.

The reproduction level of the two magnetic heads by using the expression (2), calculating a d ₂ about 0.25λ and 0.11Ramuda, it can be seen that the output of -4dB maximum output (optimum recording) is obtained . This means that when the recording track width is halved and two magnetic heads are separately recorded, a larger reproduction output can be obtained at the same recording density, considering that the output level becomes -6 dB. Means.

Second Embodiment In the first embodiment, the value of the azimuth angle was not described. However, as shown in FIG. 2, when recording / reproducing a wideband signal, crosstalk increases depending on the value of the azimuth angle.
It becomes a problem. The output degradation La due to the azimuth loss is expressed by the following equation.

La = | (sinA) / A | (5) where A = πWtanθ / λ (W is the track width, θ is the azimuth difference) In equation (5), if θ is 90 °, Crosstalk becomes zero due to azimuth loss at any recording wavelength λ.

In this embodiment, the first and second magnetic heads 1,
By providing an azimuth angle of 45 ° in each of the two in a direction opposite to the head traveling direction, an azimuth mutual difference of 90 ° is obtained, thereby making it possible to eliminate crosstalk.

Third Embodiment In the second embodiment, the azimuth angles are set to ± 45 °, but the difference between the azimuth angles may be 90 °, for example, a combination of 50 ° and 40 °. Further, the mutual difference does not need to be 90 °, and the same effect can be obtained if tan θ is in a sufficiently large range from 84 ° to 90 °.

Fourth Embodiment In the above embodiment, two magnetic heads in one set have been described. However, the present invention is also applicable to an apparatus using two to four magnetic heads or more, such as a VTR. it can.

Fifth Embodiment The configuration and manufacturing method of a magnetic head used in the above embodiment will be described. FIG. 4 shows two first and second magnetic heads 1, 2
Is a view of a so-called double azimuth head attached to the same head base 7 as viewed from the medium sliding surface side. In this figure, reference numeral 8 denotes a magnetic gap, and 9 denotes a distance from the head base reference plane to the lower end of the gap. As shown, 2
By bringing two magnetic heads close to each other and matching the heights, the recording shown in FIG. 1 can be performed. Two first, second
The magnetic heads 1 and 2 have the same gap length and track width, and have an azimuth angle of, for example, ± 45 ° clockwise.

Sixth Embodiment In the magnetic head of the above embodiment, two individual head chips were also manufactured and then attached to the head base 7, so that the head height 9 often did not match. In particular, it is fatal in an apparatus having a narrow track width and a high recording density. In order to solve this problem, a magnetic head shown in FIG. 5 is used. FIGS. 6 to 9 show an outline of a method of manufacturing a magnetic head for obtaining the main effects. In FIG. 5, reference numeral 10 denotes a non-magnetic material such as ceramic, and reference numeral 11 denotes a protrusion that slides on the medium, which regulates the track width. FIG. 5A is a slide view of the medium, and FIG. 5B is a sectional view.

Since the magnetic head shown in FIG. 5 regulates the track width by two magnetic heads integrally, the head height between the magnetic heads is always the same, and the above problem does not occur.

Next, a method of manufacturing the magnetic head shown in FIG. 5 will be described. In FIG. 6, the winding groove 1 is formed in the core block.
3, and a gap material such as SiO ₂ is formed on the upper surface 12a by vapor deposition or sputtering. Next, the magnetic gap 8 is formed by bonding with the core block 14 shown in FIG.
Next, azimuth cutting is performed as shown by a broken line, and FIG.
And joined by a mold or the like. Thereafter, the joined body 15 is ground at the position indicated by the broken line 16. The joined body 15 is joined to another joined body with the non-magnetic material 17 interposed therebetween as shown in FIG. 9A. Further, as shown in FIG. 9B, the track width is regulated by forming a groove 18 using a blade, a wire saw or laser etching, and the two magnetic heads are simultaneously processed, so that the same track width 19 and the same head height are used. 9 can be obtained. Finally, the groove 20 is filled with glass 20 and each chip is cut off to form a head chip as shown in FIG.

Seventh Embodiment In the above embodiment, the core block is mainly processed.
It goes without saying that the same applies to a MIG (mental in gap) type magnetic head made of a ferrite core block using a metal magnetic material in the gap. The same applies to a magnetic head using a laminated magnetic film sandwiched between nonmagnetic materials as shown in FIG. 10B. In FIGS. 10A and 10B, 21 is a laminated magnetic film, and 22 is a non-magnetic material. The same effect can be obtained by forming the magnetic film 21 with a large track width 19 and forming the protrusions 11 by the steps shown in FIGS.

[0041]

As described above, according to the present invention, the azimuth angles of the first and second magnetic heads are made different so that no crosstalk occurs between the two signals during reproduction.
Since tracks recorded by the first magnetic head are overwritten by the second magnetic head, the number of tracks can be reduced by half, and the track width of both heads is equalized, so that the S / N ratio can be improved by effective use of the recording medium area. Further, since signals having the same frequency band are recorded by both heads, a plurality of types of digital signals having a wide band can be recorded as they are. Then, the recording current of the first head equivalent to the recording current value to obtain a maximum reproduced output In the above configuration, and 0.4 times the recording current value to obtain a maximum reproduced output recording current value of the second head , The reproduction output of the first and second magnetic heads can be made equal, and the S / N imbalance between the reproduction outputs of the respective heads can be prevented.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing recording tracks of a magnetic recording and reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a spectrum of a recording signal of the magnetic recording / reproducing apparatus according to the embodiment of the present invention.

FIG. 3 is a diagram illustrating the relationship between recording intensity and output level.

FIG. 4 is an explanatory diagram showing a magnetic head used in the embodiment of the present invention.

5A and 5B show a magnetic head used in the embodiment of the present invention, wherein FIG. 5A is a slide view of a medium, and FIG. 5B is a sectional view.

FIG. 6 is a perspective view showing a method of manufacturing a magnetic head used in the embodiment of the present invention.

FIG. 7 is a perspective view showing a method for manufacturing a magnetic head used in the embodiment of the present invention.

FIG. 8 is a perspective view showing a method for manufacturing a magnetic head used in the embodiment of the present invention.

9A and 9B show a method of manufacturing a magnetic head used in an embodiment of the present invention, wherein FIG. 9A is an explanatory view in which a non-magnetic material is sandwiched, and FIG. 9B is a groove for restricting a track width. FIG.

FIGS. 10A and 10B show a method of manufacturing a magnetic head used in an embodiment of the present invention, wherein FIG. 10A is an explanatory view of a magnetic head chip, and FIG. 10B is an explanatory view of a magnetic head using a laminated magnetic film. is there.

FIG. 11 is an explanatory diagram showing recording tracks by a conventional magnetic recording / reproducing apparatus.

[12] in which the conventional magnetic recording and reproducing apparatus showing a recording signal spectrum, which is (a) voice, (b) the video recording spectrum diagram.

FIG. 13 is an explanatory diagram showing a deep and surface recording state of a conventional magnetic recording / reproducing apparatus.

Continuation of the front page (56) References JP-A-3-192501 (JP, A) JP-A-4-6605 (JP, A) JP-A-2-214003 (JP, A) JP-A-62-119704 (JP) JP-A-63-32702 (JP, A) JP-A-61-11910 (JP, A) JP-A-63-279406 (JP, A) JP-A-61-216108 (JP, A) 61-276102 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G11B 5/02 G11B 5/265 G11B 5/58

Claims (1)

(57) [Claims] 1. A gap length equal track width rather equal
An apparatus comprising a first magnetic head and a second magnetic head having different azimuth angles, wherein a track recorded by the first magnetic head is overwritten by a second magnetic head, and has an equal frequency band. the signals recorded by the first head and the second head is equivalent to the recording current value recorded current value of the first head to obtain a maximum reproduced output, a recording current value of the second head A magnetic recording and reproducing apparatus characterized in that the recording current is 0.4 to 0.5 times the recording current value at which the maximum reproduction output is obtained.