JPH0772932B2 - Magnetic head height adjustment method for rotary head 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 method of adjusting the height of a magnetic head in a magnetic recording / reproducing apparatus using a rotating cylinder.

[0002]

2. Description of the Related Art The positioning accuracy of a magnetic head used in a magnetic recording / reproducing apparatus is an important accuracy for determining the format of information recorded on a medium.

For example, in a video tape recorder widely used for home use, the rotary cylinder has a 180 ° angle.
Two pairs of magnetic heads mounted facing each other record and reproduce image and audio information while sequentially scanning the magnetic tape in an oblique direction. The track pitch actually recorded on the magnetic tape is as narrow as 60 μm in the 2-hour mode and 20 μm in the 6-hour mode.

If the above-mentioned two pairs of magnetic heads cannot scan these tracks accurately, the recorded information cannot be reproduced accurately and the quality of the reproduced image will be significantly deteriorated. In order to prevent this, it is necessary to accurately match the scanning pitch of the magnetic head with the above-mentioned track pitch, but the height of the magnetic head is an important factor that determines this scanning pitch.

The height of the magnetic head means the time shown in FIG.
The reference surface 5 of the lower (fixed) cylinder 2 without rolling, in FIG. 4
Is that over the distance between the gap end portion of the fixed (rotation) System cylinder 1 magnetic head ((H in FIG. 3)) that rotates in the arrow A direction. 300 is a fixed cylinder that does not rotate
Is a tape guide portion provided in the.

A conventional head height adjusting method will be described below with reference to FIG. However (Figure 4) is Ri FIG der showing a (FIG. 3) on in (rotational) cylinder section,
The lower (fixed) cylinder is omitted.

First, a spacer (not shown) having a predetermined thickness is sandwiched between the upper cylinder 1 and the head base 4 to which the head chip 3 is attached, and a rough adjustment is performed. Then, the objective lens 6 is used to adjust the head height. While observing, the insect screw 7 hitting a part of the head base 4 is screwed in the direction of the arrow 8 in the necessary adjustment amount (FIG. 5), and the head base is partially deformed. Adjust to height.

[0008]

However, as can be seen from (FIG. 5), if the pushing amount is too large, the head chip tilts too much, and the head chip is actually recorded / reproduced on the tape. Since the head hits poorly and the output is lowered, the adjustment with the screw is about 5 μm at most. .

Further, the conventional adjustment using the insect screw utilizes the mechanical deformation of the head base by pushing the insect screw within the limit of elastic deformation of the head base.
If the pushing amount of the insect screw changes due to mechanical vibration or temperature change, the deformation amount of the head base changes by that amount, and the head height may change in the end.

At present, a screw loosening preventive agent (resin that is fixed at room temperature) is used for insect screws in an attempt to minimize the influence from these factors, but the effect is not sufficient, and it is several microns. The head height had changed in the order of.

[0011]

[0012]

The present invention solves the above problems and provides a magnetic head
Head unit consisting of a rotary cylinder and a fixed cylinder
In, without tilting the head chip, including a vibration, etc.
It is an object of the present invention to provide a highly accurate head height adjustment method in which the head height after adjustment does not change due to the influence of the external environment .

[0014]

Means for Solving the Problems The present invention for achieving the above object, a magnetic head comprising a sticking head chip head base and the head base, said magnetic heads
A rotary cylinder that fixes and rotates the cylinder, and the rotary cylinder
Supporter so that it can rotate and has a tape guide
A rotary head device consisting of a fixed cylinder and
The head chip attachment surface of the head base of the magnetic head, and the plasticity of the head base caused by irradiating the head chip attachment portion of the surface on which the head chip is not attached with laser light By using deformation, the fixed cylinder of the magnetic head
The head height for the head is adjusted.

[0015]

The present invention applies the head chip to the head base.
The laser beam is applied to both the
The head tip is tilted because it plastically deforms the stairs
Without changing the head tip posture before adjustment
It can be adjusted. Therefore, before and after adjustment
Contact state (head touch) of the tape changes
Since it does not happen, it remains stable even after major adjustments.
Output is obtained. That is, in the present invention, the adjustment amount
It is possible to always obtain a stable head output without depending on it.
Is. The present invention does not use moving parts such as adjusting screws.
It is a method of adjusting by plastic deformation of the head base.
Causes the head height after adjustment to change over time or cause mechanical vibration.
It does not change depending on the situation. Therefore adjusted by the present invention
The rotary head device is stable and highly reliable. It
Moreover, in the present invention, plastic deformation is performed instead of elastic deformation.
Is larger than the elastic limit of the head base material.
Adjustment is possible even when an adjustment amount is required.

[0016]

EXAMPLE FIG. 1A is a perspective view of a magnetic head whose head height is adjusted according to the present invention. The height adjusting method will be described with reference to FIGS. 1 (b) and 1 (c).

First, as shown in FIG. 1B, the head
Head base made of brass with a thickness of 1.5 mm
The fourth magnetic head 100 comprising pasted on the main surface of the magnetic head 100 mounted to the rotary cylinder later fixed by set screw 11 so as to come into contact with the reference block 5. When the head height was measured by the objective lens 6, the height d was 65.3 μm. If the predetermined height is 80.0 μm, it is necessary to deform the head base 4 toward the reference block 5 side by the difference of 14.7 μm. In this embodiment, the head base 4 described below is used.
After the deformation, the magnetic head 100 is changed to a rotating cylinder.
The rotary head device was completed by mounting.

The deformation caused by the irradiation of the laser light is as shown in FIG.
As shown in (c)), it is an angular deformation inclined to the laser irradiation side, and if the required height adjustment amount is Δd and the irradiation interval from both surfaces of the head base is a, the angle change amount θ (radian) There is a relation (Formula 1) between and.

Δd = a × sin θ (Equation 1) In the present embodiment, Δd is 14.7 μm and the irradiation interval a is 1 mm as described above. It can be seen that it is 14.7 milliradians.

On the other hand, short pulse oscillation of an Nd: YAG laser (wavelength 1.06 μm) was used as the laser light, and the energy was adjusted to about 3 joules per pulse. When this pulsed laser light was applied to the vicinity of the chip attaching portion of the brass head base, it was possible to cause angular deformation of 1 mm radian per pulse.

Since such angular deformation has additivity, the total variation amount is adjusted in this embodiment by the total number of pulses of the laser light to be irradiated.

The actual deformation was performed by the procedure described below.
In FIG. 1C, first, a portion 20 of the surface of the head base 4 on which the chip 3 is attached, which is relatively far from the chip.
The pulsed laser light 30 was irradiated 15 times. Next, with respect to the surface opposite to the previously irradiated surface, set the irradiation position to 1 m.
The pulsed laser light 31 was irradiated 15 times to the portion 21 which was closer to the chip side by m as in the previous case. However,
The second irradiation of the laser beam 31 is inclined obliquely so that it becomes perpendicular to the head base that is obliquely deformed by the previous irradiation.

As a result of adjusting the head height by the above-described angular deformation, as shown in FIG. 1C , the final head height d becomes 80.5 μm, which is only 0. The deviation was 5 μm, which was impossible in the past 5
Adjustment of μm or more could be performed without tilting the head chip. Furthermore, by repeating -40 ℃ and 80 ℃ 1
Even when the heat shock test was performed for 0 hours, the amount of deformation only changed within 0.1 μm, which proved to be an extremely reliable adjustment method.

In the above embodiment, the head base is
The head height is adjusted for the case where only one head chip is bonded, but it is also possible to perform the same adjustment for a plurality of head chips as shown in (Fig. 2). Is obvious. Further, the accuracy and reliability of the height adjustment according to the present invention are not limited by the irradiation order to the head base, the interval between irradiation positions, and the like.

Furthermore, in this embodiment, the total number of pulses of the laser light to be irradiated is controlled to adjust the deformation amount of the head base, but other control may be used. For example, power control. Further, even if the size or material of the head base is changed, it is obvious that the same adjustment can be performed by appropriately setting the laser irradiation conditions.

In the present embodiment, welding deformation by irradiation with laser light using light energy was used, but in principle, any method can be used as long as local heating can be performed. Examples include arc welding using electron energy, electron beam welding, ultrasonic welding using ultrasonic energy, and gas welding using chemical energy.

[0027]

As mentioned in the above embodiment according to the present invention, according to the present invention, plastic deformation by irradiating a laser beam to the head base both surfaces
Be to form, even if that requires a significant adjustment of the above 5 [mu] m, it is possible to adjust the height of the plurality of head chips with high precision without deteriorating the contact relative to the tape of the head chip, was only stable even with high accuracy Has head height
A rotary head device is obtained . The present invention also includes an adjusting screw.
Since the configuration does not require
The number of parts such as the height adjustment screw is reduced, and the adjustment work is complicated.
It is possible to save the work, in addition to the merit of cost reduction,
This enables mass production of more reliable VTRs.

[Brief description of drawings]

FIG. 1A is a perspective view of a magnetic head whose height is adjusted according to the present invention. (B), (c) is an enlarged view for explaining the adjusting method of (a).

FIG. 2 is a perspective view of a magnetic head to which two head chips whose height is adjusted according to the present invention are attached.

FIG. 3 is a rotary head including upper and lower cylinders and a magnetic head.
It is a block diagram of a drive device and is an explanatory view of the definition of the head height .

FIG. 4 is a sectional view of a cylinder for explaining a conventional head height adjusting method.

5 is an enlarged view of a main part of the cylinder of FIG.

[Explanation of symbols]

 1 Upper Cylinder 2 Lower Cylinder 3 Head Chip 4 Head Base 5 Reference Block 6 Objective Lens 7 Bug Screw 11 Fixing Screw 30,31 Laser Light

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoshiaki Maekawa 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-1-227279 (JP, A) 45037 (JP, U)

Claims (1)

[Claims] 1. A magnetic head comprising a head base and the sticking head chips to the head base, said magnetic f
A rotating cylinder that fixes and rotates the head and the rotating cylinder.
The tape guide so that it can rotate and the tape guide
A rotary head device consisting of a fixed cylinder and
The head chip attachment surface of the head base of the magnetic head, and the plasticity of the head base caused by irradiating the head chip attachment portion of the surface on which the head chip is not attached with laser light By using deformation, the fixed cylinder of the magnetic head
Times, characterized in that the head height is adjusted against
A method for adjusting the height of a magnetic head of a rotary head device .