JPH0612618A - Multichannel magnetic head and magnetic recording method using it - Google Patents

Abstract

PURPOSE:To improve the accuracy of deciding the position of an element by arranging channels based on a jumping scan recording method. CONSTITUTION:Channels are devided into preceding and following groups 11 and 12, CH 2 and 4 belong to the group 11 and CH 1 and 3 belong to the group 12. Respective gaps 2a and 4a of the group 11 are linearly arranged having an azimuth angle theta1 and the gaps of the group 12 are formed likewise having an azimuth angle theta2. For the track width of each channel, the preceding sides W2 and W4 are bigger than the following sides W1 and W3. Also, each track end is provided with an overlapping amount DELTAW for allowing an overlapped writing. Thus, since the groups 11 and 12 are constituted having the same azimuth angle, head elements in the group are integrally formed, the azimuth angles of the respective gaps are made uniform and the position is highly accurately and easily decided.

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 multi-channel magnetic head suitable for a high quality VTR, a digital VTR, etc. and a magnetic recording method.

[0002]

2. Description of the Related Art As compared with a conventional VTR, a high-definition VTR, a digital VTR, etc. have a significantly increased signal band and information amount, and therefore a signal is divided into a plurality of channels for recording.
The multi-channel recording system is adopted. Therefore, a multi-channel magnetic head in which the head track position, gap position, azimuth angle, etc. of each channel are precisely positioned is required. As an example of such a magnetic head, a quadruple multi-channel magnetic head in which four head elements are attached to a common base 55 is shown in FIG. 5
1,52,53,54 are ferrite or metal composite type (M
IG) head element and the gaps 51a, 52
a, 53a, and 54a are arranged at predetermined intervals in the scanning direction and the track width direction so as to sequentially form a recording pattern. The azimuth angle of each gap is different for each track. Various proposals have been made for improving the method of assembling such a multi-channel magnetic head. See, for example, JP-A-2-94010.

[0003]

Problems common to multi-channel magnetic heads include the following.

1. When each head element is attached to the base, each gap must be three-dimensionally positioned with high precision, which makes the operation difficult. If the gaps of adjacent channels are simultaneously made to be integrated, a combination of different azimuth angles becomes an obstacle.

2. In order to avoid crosstalk between channels, the head elements are arranged at a considerable distance in the scanning direction.
Therefore, it is difficult to make uniform tape contact with each element. Further, as the number of channels increases, it becomes difficult to secure a space for mounting the head in the small cylinder.

[0006]

In order to achieve the above object, according to the present invention, in a multi-channel magnetic head comprising a group of leading channels which interlace-scans tracks and a group of trailing channels which scans gap tracks, a group of leading channels is provided. The azimuth angle of the following channel group was made different, and the head track width of the preceding channel group was made larger than the head track width of the following channel group. Further, the preceding channel group or the following channel group is composed of a plurality of thin film elements in which the gaps are arranged in a straight line at predetermined intervals. In addition, a magnetic recording method was used in which overwriting recording was performed using a multi-channel magnetic head, and the recording pattern width of the preceding channel group was smaller than the recording pattern width of the following channel group.

[0007]

Function: The leading channel group and the trailing channel group are separated, the head gaps in each group are arranged in a straight line, and their azimuth angles are the same. As a result, the gaps of the respective channels can be integrally formed at the same time without impairing the accuracy of the azimuth angle, and the positioning accuracy is dramatically improved. At that time, if a thin film head structure in which the magnetic core and the signal coil are formed of a thin film is used, crosstalk between adjacent channels can be reduced and adjacent arrangement can be made, tape contact becomes good, and even if the number of channels increases Can be mounted on a cylinder in space. Further, the output deviation between the channels due to the interlaced scanning can be eliminated by making the track width of the preceding head larger than the track width of the following head. In particular, with respect to the output fluctuation due to the tracking error, regarding the pattern width after recording, the pattern width scanned by the preceding head is made smaller than the pattern width of the succeeding head, so that the average output considering the tracking margin becomes uniform.

[0008]

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

FIG. 1 shows a first embodiment of a multi-channel magnetic head according to the present invention, and shows a gap arrangement when the number of channels as viewed from the tape sliding surface side is four. The head scanned in the direction of arrow 10 to separate the channels into a leading group 11 and a trailing group 12. CH2,4 is the leading side, CH1,3
Is the trailing channel. Track height is CH1,
The tracks are arranged in the order of 2, 3 and 4, and tracks are formed in this order on the tape. The gaps 2a and 4a of the front channel group 11 are arranged in a straight line to have an azimuth angle θ ₁ (for example, + 10 °). Similarly, the gaps 1a and 3a of the channel group 12 on the trailing side are also formed in a straight line to form an azimuth angle θ ₂
(For example, −10 °). The track width of each channel is set such that the values W ₂ and W ₄ on the leading side are larger than the values W ₁ and W ₃ on the trailing side. For example, W ₂ = W ₄ = 15 μm, W ₁ = W ₃ = 10 μm
m. In addition, each track end is overlapped by ΔW
(= 2.5 μm) is provided so that overwriting can be performed.

The multi-channel magnetic head having such a structure has the preceding channel group 11 as compared with the conventional magnetic head.
Alternatively, since the succeeding channel groups 12 are formed with the same azimuth angle, the head elements in the group can be integrally manufactured, and the azimuth angles of the gaps can be made uniform, and the high-accuracy positioning can be facilitated. Further, the length L of the head sliding surface in the scanning direction is shortened (1/2 compared to the conventional one), and the contact between the tape and the head becomes much more stable.

FIG. 2 is a tape pattern diagram showing a magnetic recording method using the multi-channel magnetic head of the present invention. The head scans in the direction of arrow 10, and the tape 13 runs in the direction of arrow 14. Among the four channels, the leading channels CH2 and 4 are interlaced by one track, and the trailing channels CH1 and CH3 are scanned so as to fill the gap tracks. When the track width of each channel is the numerical value of the first embodiment, the recording pattern width after head scanning is ₁ on both the leading side T ₂ , T ₄ and the trailing side T ₁ , T _3.
It becomes 0 μm (ignoring the fringe portion at the track end).
Therefore, the head output of each channel during reproduction becomes the same level.

Next, a second embodiment of the multi-channel magnetic head of the present invention will be described. The basic configuration is the same as that of FIG. 1, but the track width of the preceding channel group 11 is set to W ₂
= W ₄ = 15 μm, the track width of the succeeding channel group 12 is W ₁ = W ₃ = 11 μm, and the overlap ΔW =
It was 3 μm. As a result, the print pattern width after head scanning is as shown in FIG. 2 in which the preceding channel T ₂ = T ₄ = 9 μm,
The trailing side channel T ₁ = T ₃ = 11 μm, and the leading side is smaller than the trailing side. Therefore, the head output at the time of reproduction in this case is different on the leading side and the trailing side.

In the multi-channel recording method, it is necessary to minimize the output deviation of each channel. Especially in the case of high density recording with a small track width, the influence of tracking accuracy must be taken into consideration. FIG. 3 shows the change in the output of each channel with respect to the tracking error during reproduction. (A) is the case of the first embodiment, (b) is the second
This is the case of the embodiment. In (a), the maximum output of each channel (during just tracking) is equal (E ₁ = E ₂ =
E ₃ = E ₄ ). The leading side (CH2, CH4) has an output flat portion (tracking margin), but the trailing side (C
H1 and CH3) do not have a flat portion, and the output is hypersensitive to tracking errors. Therefore, the output deviation between channels becomes large. On the other hand, in (b), although the maximum output of each channel is different (E ₁ = E ₃ > E ₂ = E ₄ ), when a tracking error occurs, the magnitude relationship of the outputs is reversed (E ₁ = E ₃ <E ₂ = E ₄ ). If the cross point CP is set so as to come to the center of the tracking operation range ΔT, the inter-channel deviation can be minimized. That is, in the interlaced scanning recording as in the present invention, it is more preferable to alternately change the recording pattern widths T ₁ , T ₂ , T ₃ and T ₄ . The numerical value may be appropriately selected in consideration of the tracking accuracy of the applied device.

FIG. 4 shows a thin film head suitable for the multi-channel magnetic head of the present invention, which corresponds to the leading channel group or the trailing channel group. Two-channel thin film head elements 21, 2 on the common non-magnetic substrate 25.
3 were formed in close proximity. 21a and 23a are gaps 3
1, 33 are magnetic thin film cores, and 41, 43 are thin film coils. Since each element is formed on a common plane, the azimuth angles of them are aligned, and since they are formed by photolithography technology, the track widths W ₁ and W ₃ of each channel can be realized with extremely high accuracy, and after that No need for positioning work. Further, since the magnetic core is composed of the thin films 31 and 33, crosstalk between channels is reduced, each element can be arranged close to each other, and the track density is greatly improved.

Further, FIG. 5 shows another example of a thin film head suitable for the multi-channel magnetic head of the present invention. Thin film head elements 21, 22, 23 and 24 are formed on both sides of non-magnetic substrates that are not parallel to each other. If the substrate angles θ ₁ and θ ₂ of the element formation surface are selected equal to the azimuth angle, all channels are integrated. Can be formed by, and the head assembly is easier. As a result, the contact of the tape head becomes better, and the tape can be installed in a small space in a small cylinder.

In the above description, the case where the number of channels is 4 has been described as an example, but it goes without saying that the present invention is also effective in other cases.

[0017]

In the multi-channel magnetic head,
Since the arrangement of the channels is based on the interlaced scanning recording method, each element can be manufactured integrally, and the positioning accuracy of each element is significantly improved. Further, since the multi-channel magnetic head is composed of a thin film head element, it is possible to provide a magnetic head suitable for mounting on a small cylinder, which allows close placement, good contact of the tape head, high track density.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a channel arrangement of a multi-channel magnetic head according to the present invention.

FIG. 2 is a tape pattern diagram recorded using the multi-channel magnetic head of the present invention.

FIG. 3 is an output characteristic diagram of the multi-channel magnetic head of the present invention.

FIG. 4 is a diagram showing a thin film head suitable for the multi-channel magnetic head of the present invention.

FIG. 5 is a diagram showing another thin film head suitable for the multi-channel magnetic head of the present invention.

FIG. 6 is a diagram showing an example of a conventional multi-channel magnetic head.

[Explanation of symbols]

CH1, CH2, CH3, CH4 ... Channel, 1a,
2a, 3a, 4a ... _{gap, W 1, W 2, W} 3, W 4 ... track _{width, T 1, T 2, T} 3, T 4 ... recording pattern width, 2
1, 22, 23, 24 ... Thin film element.

Claims (3)

[Claims] 1. A multi-channel magnetic head comprising a preceding channel group for interlacing scanning tracks and a following channel group for scanning gap tracks, wherein the preceding channel group and the following channel group have different azimuth angles and the preceding channel group. The multi-channel magnetic head is characterized in that the head track width of the is larger than the head track width of the succeeding channel group. 2. A multi-channel magnetic head characterized in that the preceding channel group or the following channel group of claim 1 is constituted by a plurality of thin film elements in which respective gaps are arranged in a straight line at predetermined intervals. 3. The magnetic recording according to claim 1, wherein the multi-channel magnetic head is used for overwriting recording, and the recording pattern width of the preceding channel group is made smaller than the recording pattern width of the following channel group. Recording method.