JPH03224110A - Magnetic head and magnetic reproducing device using this magnetic head - Google Patents

Abstract

PURPOSE:To obtain the magnetic head which suppresses the crosstalk of the long wavelength signal from a 2nd proximity track at the time of reproduction without degrading wear resistance by providing a notched groove to regulate a track width to satisfy specific conditions in the side part of a magnetic gap. CONSTITUTION:The notched groove is so formed as to satisfy equation I when the opposite gap length of a pair of magnetic core half bodies in the position of the notched groove apart by z in the transverse direction of a surface for sliding contact with a medium from the mid-point in the track part of the magnetic gap on the surface for sliding contact with the medium is designated as G (z), the track pitch of the signal recorded on the medium as Tp and the longest recording wavelength as lambda. The crosstalk from the 2nd proximity track at the time of reproduction is suppressed and the good reproducing is executed without degrading wear resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a magnetic head and a magnetic reproducing apparatus using the magnetic head.

(b) Conventional technology VTR (+: '7' audio player: I-ta), DAT (
The media sliding contact surface of magnetic heads used in magnetic recording and reproducing devices such as digital audio tape recorders ensures smooth sliding with the media and wear resistance, and is compatible with narrowing head gap track widths. Therefore, it is formed into a shape as shown in FIG. That is, in a magnetic head in which a magnetic gap (2) is formed by a pair of magnetic core halves (la) and (lb) made of a magnetic material such as ferrite abutting against each other with a non-magnetic material interposed therebetween, the magnetic core halves are Notch grooves (3) (3) for regulating the track width are provided on both sides of the magnetic gap (2) of the body (la) (lb),
A non-magnetic bonding material such as glass (
4) (4) is filled.

In addition, as shown in FIG. 7, when the opposing surfaces (3a) (3a) (3a) (3a) of the cutout grooves (3) (3) are parallel to each other, that portion acts as a gap and the signal During reproduction, there is a possibility that long wavelength signals from adjacent tracks may be reproduced.

On the other hand, in order to improve the recording density in a magnetic recording system, particularly to improve the track density, it is effective to reduce the width of the recording track itself as described above, as well as to narrow the guard band by azimuth recording. For example, R-DA
Azimuth angle ±20° for T (rotating head type DAT)
Track and pitch T, 13.6 μm, recording is performed without guard band.

Furthermore, in order to reproduce a signal recorded at a high track density, it is required that the reproducing head accurately trace the recorded track. The above-mentioned requirements are important because a so-called area division method is adopted in which tracking errors are detected and corrected by comparing crosstalk components of a rectangular pilot signal from both adjacent tracks.

Note that in R-DAT, among the signals recorded on the recording track, the signal having the longest recording wavelength is the pilot signal.

As a measure to improve track density in magnetic recording systems, eliminating or utilizing the influence of crosstalk from the closest tracks is considered as described above. There is little consideration given to the influence of crosstalk from

For example, corresponding to the R-DAT system, the azimuth angle is 20
° A conceivable tape sliding contact surface shape of a magnetic head that has a track width Tw of 20 μm and also takes into consideration the drawbacks explained in FIG. 7 above is as shown in FIG. 8.
When this head is actually used, a drawback arises in that the tracking becomes unstable due to the influence of crosstalk from the second adjacent track on the ATF pilot signal.

Here, when the above-mentioned problem regarding the ATF pilot signal of the R-DAT system is analyzed in more detail, the following facts or considerations are obtained.

■ Pilot signal P4 in the R-DAT system,
A part of the recording pattern of Pl, Pl, P4, P on the magnetic tape is determined as shown in FIG.
When traced above in the direction of arrow B, pilot signal envelopes Q4, Q2, and Q as shown in FIG. 10 are detected. Note that the envelopes Q1, Qo, and Q correspond to the pilot signals P1, Pl, and P, respectively. However, it has been found that when a certain type of head is used to detect such a pilot signal, the envelope Q fluctuates and tracking becomes unstable.

The variation in the envelope Q is caused by the fact that when the playback head traces track #3, the track end of the head detects the pilot signal P of the second adjacent track #2, and at the same time detects the pilot signal P from the second adjacent track #5. This is thought to be due to interference from crosstalk of the signal P. Note that the diagonal direction of the pilot signals in FIG. 9 indicates the azimuth direction, and the pilot signals P7, Pl, P
.

and pilot signals P2 and P4 have opposite azimuths.

■ Using a magnetic head whose tape sliding surface has the shape shown in FIG. 8, a pilot signal is recorded on only one track as shown in FIG.
) When the change in the signal detection level depending on the amount of tracking deviation X of the trace position was measured, the results shown in FIG. 11 were obtained. (I) and (II) in FIG. 11 are cases where the tape sliding surface width Rw is 40 μm and 180 μm, respectively. As can be seen from FIG. 11, in case (I) using a head with a small tape sliding contact surface width RW, the signal detection level decreases monotonically as the tracking deviation amount X increases; In the case of (TI) using a head with a large width Rw, the signal detection level attenuates gradually when the tracking deviation amount X is around 25 to 35 μm, and the signal detection level increases again when the tracking deviation amount X is around 40 μm. Initially, the signal detection level reaches a peak when the tracking deviation amount X is around 50 μm. It is thought that the deviation of the signal detection level from monotonous attenuation in the case of (TI) is caused by the notch grooves (3) (3) in the tape sliding surface acting as a large gap. In addition, (I
) (II) When the actual pilot signal recording pattern shown in FIG. 9 was reproduced using a magnetic head corresponding to (II), the variation observed in the envelope Q in FIG. 10 was due to (II). This was only possible when using a magnetic head compatible with .

■ From the above, AT in the R-DAT system
It is considered that the envelope fluctuation of the F pilot signal occurs because the notched grooves on both sides of the magnetic gap on the tape sliding surface of the magnetic head act as a gap to detect the pilot signal of the second adjacent track.

As a solution to the above problem, it is possible to reduce the width Rw of the tape sliding surface as in the case (I) of Fig. 11, but this method is not very effective when considering the wear resistance of the head. This is not preferable, and it is necessary to secure a certain width of the tape sliding surface and then suppress the detection level of the pilot signal caused by the notch groove.

(c) Problems to be Solved by the Invention The present invention has been made in view of the drawbacks of the above-mentioned conventional examples.
It is an object of the present invention to provide a magnetic head that suppresses crosstalk of long wavelength signals from a second adjacent track during reproduction without reducing wear resistance.

Furthermore, the present invention suppresses the adverse effects of crosstalk from the second adjacent track during playback, and particularly when detecting a tracking error using a pilot signal from the adjacent track as in the R-DAT system, the second adjacent track It is an object of the present invention to provide a magnetic reproducing device that prevents tracking from becoming unstable due to the influence of Talostalk from the magnetic field.

(d) Means for Solving the Problems The present invention abuts a pair of magnetic core halves made of a magnetic material through a non-magnetic material to form a magnetic gap, and regulates the track width on the sides of the magnetic gap. The pair of magnetic heads are provided with a notch groove in which the magnetic head is located at a position of the notch groove that is 2 points apart in the width direction of the medium sliding contact surface from the center point of the track portion of the magnetic gap on the medium sliding contact surface. When the length of the opposing gap between the core halves is G(z), the track pitch of the signal recorded on the medium is TP, and the longest recording wavelength is λ, then G(2Tp)>3λ and l z are satisfied. It is characterized in that the cutout groove is formed.

Further, a magnetic reproducing apparatus according to the present invention is characterized in that the above-described magnetic head is used.

Furthermore, the magnetic reproducing apparatus of the present invention is characterized in that tracking errors of the magnetic head are detected using pilot signals on adjacent tracks.

(E) Effect According to the magnetic head having the above structure, the gap loss for long wavelength signals of the notch groove which traces on the second adjacent track and acts as a reproduction gap during reproduction becomes large, and the gap loss from the second adjacent track increases. Talostalk is reduced.

Further, according to the above-described magnetic reproducing device, crosstalk of long wavelength signals from the second adjacent track to the scanning track can be suppressed, and especially in a device that detects tracking errors using pilot signals from the adjacent track, Tracking is prevented from becoming unstable due to the influence of crosstalk from the second adjacent track.

(F) Example Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing the tape sliding surface of the magnetic head of this embodiment, and the same parts as in FIG. 8 are given the same reference numerals, and their explanation will be omitted.

The shape of the notch grooves (5) (5) of the magnetic head of this embodiment is the first portion (6a) (6b) (6c) (6d) extending in a direction perpendicular to the extending direction of the magnetic gap (2). ) and second parts (7a) (7b) (
7c) (7d). In addition, between the magnetic core halves (la) and (lb) of the notch groove (5) at a position 2 apart from the midpoint (10) of the track portion of the magnetic gap (2) in the media sliding width direction A, The opposing gap length is G(z
).

First, as shown in Fig. 2, a pilot signal having the longest recording wavelength λ = 24 μm on the recording track is recorded only on one track (8) (track pitch T, = 13.6 μm), and this pilot signal is Consider the case where the notch groove (5) of the magnetic head of this embodiment shown in FIG. 1 is used for reproduction.

In this case, the reproduction output E is generated by a virtual head whose track width is minute track width dz and whose gap length is the opposing gap length G(z) between the magnetic core halves (la) and (lb) in the notch groove (5). It can be considered that the output is added over the recording track width T, and the following equation is obtained. Zo is the track portion (13) of the magnetic gap (2)
) is the shortest distance from the midpoint of track (8).

Further, the integrand term in the above equation (1) corresponds to a so-called gap loss, and this integrand term is illustrated as shown in FIG. 3.

In the R-DAT system, the cause of the envelope fluctuation of the ATF pilot signal is the crosstalk from the second adjacent track, and the output from the second adjacent track is transformed from the above equation (1) as follows. . In the magnetic head as shown in FIG. 1, dz/dG does not change significantly within the integration range of (1) above, and the following equation is obtained.

Here, as can be seen from the above-mentioned Fig. 3, if the center position of the integral range becomes larger than 3λ, that is, G(2Tp)>3λ
...If the condition (4) is satisfied, the absolute value of the integrand term in the above equation (3) becomes considerably small. Moreover, when the size of the integration range becomes larger than λ, that is, when the following conditions are satisfied, the sign (±) of the integrand term in the above equation (3) is reversed at least once during the integration range,
The integral value becomes smaller. Therefore, if the conditions of the above equations (4) and (5) are satisfied, assuming that the longest recording wavelength of the signal recorded on the recording track is λ, then the absolute value of the integral of the above equation (3), that is, the Long wavelength signals from two adjacent tracks (
(pilot signal) crosstalk can be suppressed to a certain level.

As a specific example of the present invention, FIGS. 4(a), (b) (C
) (d) A magnetic head having a tape sliding contact surface structure as shown in (d) is mentioned. The azimuth angle of the magnetic gap (2) is 20°, the track width is 20 μm, and the tape sliding surface width Rw is 80 μm. That is, in each of these embodiments, the tape sliding surface width Rw is approximately four times the track width in order to ensure wear resistance, and the notch 9 groove ( 5) The shape of (5) has the lengths It of the first portions (6a), (6b), (6c), and (6d) extending perpendicularly to the extending direction of the magnetic gap (2), 1. ,! 1.24, and the first part (6a)
The inclination angle θ7 of the second portion (7a) (7b) (7c) (7d) that is inclined with respect to (6b) (6c) (6d),
θ2, θ1, θ4 in Figure 4 (a) (b) (c) (
By setting the values shown in d), the above equations (4) and (5) are satisfied.

Also, the length satisfies the above equations (4) and (5)! 1
．． 18.23.24 and inclination angles θ1, θ2, θ5, θ4
In addition to the example shown in FIG. 4, combinations such as those shown in (1), (ii), and (iii) below are also conceivable.

(i) l+-14>40pm, θ1~θ4>25° (ii) 11-14>20pm, θ, ~θ, >40
'(iii) l, ~24〉0μm, θ, ~θ4
>55"The lengths 21 to A are not necessarily equal to each other, and may have different values, for example, as shown in FIG. The change may be made in two or more steps as shown in (C).Also, in Figure 4 (d)
) shows an example of application of the present invention to a case where the track portion of the head is shifted upward from the center position in the width direction of the tape sliding surface in order to improve the contact state between the head and the tape during mounting.

Next, as an example for confirming the effects of the present invention, FIG.
) Using a magnetic head having the medium sliding surface shown in FIG.
Shown in Figure 2. In Figure 12, (III) is the result when the magnetic head of the present invention was used, and (I) and (II) are re-drawings of (I) and (II) in Figure 11 as comparative examples. . As can be seen from FIG. 12, in the case of (III) using the magnetic head of the present invention, a small peak was observed near x = 50 μm, which is the cause of pilot signal crosstalk in R-DAT system of Relmo. In the vicinity of the second adjacent track, that is, in the vicinity of x=25 to 30 μm, the signal detection level is comparable to that of the preferable comparative example (IT).

The core material of the magnetic head of the present invention may be an oxide magnetic material such as ferrite, an alloy magnetic material such as Sendust, or
As shown in Figures (a) and (b), a composite in which alloy magnetic material films (12a) (12b) such as sendust are provided near the gap (2) of oxide magnetic material cores (lla) (llb) such as ferrite. There are core materials etc. The alloy magnetic material films (12a) and (12b) in the composite core material are made of an oxide magnetic material core (11a011b) with a low saturation magnetic flux density in response to the adoption of high coercive force media in R-DAT systems and the like. This was formed to compensate for the lack of recording ability. In addition, in FIG. 12(b), the alloy magnetic material film (12a) (1
2b) and the oxide magnetic material core (11a) (llb), the bonding interface is made non-parallel to the magnetic gap (2) in order to prevent the bonding interface from acting as a pseudo gap.

Although the above description has focused on the R-DAT system, it goes without saying that the present invention is also applicable to other magnetic reproducing devices other than the R-DAT system.

(G) Effects of the Invention According to the present invention, it is possible to provide a magnetic head that can suppress crosstalk from the second adjacent track during reproduction and perform good reproduction without reducing wear resistance. .

Further, according to the present invention, the magnetic field suppresses the adverse effects of crosstalk from a second adjacent track during playback, and enables good tracking, especially in a device that detects tracking errors using pilot signals from adjacent tracks. A playback device may be provided.

[Brief explanation of drawings]

1 to 5 relate to the present invention, in which FIG. 1 shows the medium sliding contact surface of the magnetic head, FIG. 2 shows the tracking position of the magnetic head, and FIG. 3 shows the gap loss. , FIG. 4, and FIG. 5 are views showing the medium sliding contact surface, respectively. 6th
7 and 8 respectively show the medium sliding contact surface of a conventional magnetic head, FIG. 9 shows the recording pattern of the pilot signal, FIG. 10 shows the envelope waveform, and FIG.
1 and 12 are diagrams showing the detection level of the pilot signal depending on the trace position of the reproducing head, respectively. (la) (lb)...Magnetic core half (2)...Magnetic gap (5)...Notch groove

Claims (3)

[Claims] (1) A magnetic head in which a pair of magnetic core halves made of a magnetic material are brought into contact with each other via a non-magnetic material to form a magnetic gap, and a notch groove is provided on the side of the magnetic gap to regulate the track width. z in the width direction of the medium sliding contact surface from the midpoint of the track portion of the magnetic gap on the medium sliding contact surface.
When the length of the opposing gap between the pair of magnetic core halves at the positions of the notch grooves separated by the same amount is G(z), the track pitch of the signal recorded on the medium is T_p, and the longest recording wavelength is λ. , G(2T_p)>3λ, and G(5/2T_p)−G(3/2T_p)>λ. (2) A magnetic reproducing device using the magnetic head according to claim (1). (3) The magnetic reproducing apparatus according to claim (2), wherein a tracking error of the magnetic head is detected using a pilot signal on an adjacent track.