JPS629516A - Floating type magnetic head device - Google Patents

Abstract

PURPOSE:To improve the performance and reliability of the titled device by providing a moving means moving a support to a recording medium in approaching and parting direction with a signal detected by a distance detection means detecting the distance between a slider and the recording medium. CONSTITUTION:A gimbal 9 being an energizing member to a magnetic disc 17, and a slider 11 having a magnetic head and an objective lens 7 collecting the light generated from a laser 19 to the magnetic disc 17 are provided to a support cylinder 5. The distance between the slider 11 and the magnetic disc 17 is detected by a photodiode 29 by receiving a light reflected in the magnetic disc 17 through the objective lens 7. When the distance between the slider 11 and the magnetic disc 17 is kept properly, the photodiode 29 produces no differential output but if the slider 11 comes to an abnormity such as a projection on the magnetic disc, the diameter of the light spot on the optical disc 17 is larger, the photodiode causes a differential output, the detection signal is given to a coil 13 and the distance between the slider 11 and the magnetic disc 17 is kept properly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention applies to a floating magnetic head device used in a magnetic disk device, etc. Ill.

[Prior art]

Generally, in a floating magnetic head device, a slider equipped with a magnetic head floats with a small gap of ω relative to the surface of a recording medium such as a magnetic disk, and the slider and the recording medium move relative to each other to perform recording. Controls recording and reproduction of media. In particular, in recent years, the amount of information processed by computers has tended to increase, and in order to cope with this, it is necessary to move the slider even closer to the recording medium, and recently the gap has been reduced to 1 μl or less.

FIG. 3 schematically shows such a floating magnetic head device, in which a slider 1 floats above a magnetic disk 101 as a recording medium with a minute gap 103 formed during operation.
05 is disposed, and this slider 105 has a head portion 1 having a coil 107 and a head gap 109.
11 are provided. The slider 105 is pressed against the magnetic disk 101 at a pivot 115 by a leaf spring 113 called a gimbal.

When the magnetic disk 101 is stationary with respect to the slider 105, that is, when the head is stopped, the slider 105 is in contact with the magnetic disk 101.

In response, when the device operates and the magnetic disk 101 rotates, causing a relative shift f7J'r in the direction of the arrow in the figure, the slider 1
Air flows between the slider 105 and the magnetic disk 101 from the left direction in the figure, and a floating blade is created on the slider 105. When the pressing forces of the floating blade and the leaf spring 113 are balanced, the slider 105 stably floats. As mentioned above, this flying height has recently become less than 1 μm, and in this state, by passing current through the coil 107, recording can be performed using the magnetic field generated in the head gap 109, or the magnetic disk flowing from the head gap 109 can be recorded. A reproduction output is obtained by the magnetic flux from 101.

[Problem that the invention seeks to solve]

However, in recent years, theoretical analysis of slider shapes has progressed, and floating heads that operate stably at submicron flying heights have been developed, but they basically have the following problems.

(1) The surface of a magnetic disk is generally not ideally flat; in reality, it has undulations of approximately ±50 μm or a few to several tens of μm.
There are irregularities at the pitch of , and there are also vibrations in the rotating system, so even if the magnetic disk surface is flat, there will be vibrations and small undulations in the rotating magnetic disk. For this reason, the slider must move up and down sufficiently to follow these surface runouts and small waviness to maintain a constant distance from the magnetic disk surface. Therefore, it is necessary to increase the pressing force of the leaf spring against the slider to a sufficient extent to allow for fluctuations in image quality.

However, if the pressing force is large, the posture of the slider will collapse due to minute protrusions on the surface of the magnetic disk, and the slider and magnetic disk will come into contact with each other, which may cause the head section to collapse.

In addition, in order to follow high-frequency undulations with short periods,
Efforts have been made to downsize the slider and increase its resonance point. However, if the slider is made smaller, its floating blade will also become smaller, and the influence of external disturbances such as waviness of the magnetic disk will become greater. For this reason, the shape of the slider is required to be highly accurate, and manufacturing thereof tends to be difficult.

(2) When the rotation of the magnetic disk is stopped, the slider is in contact with the surface of the magnetic disk, so it takes a short time for the slider to rotate on the magnetic disk and make the slider levitate again. There is a state in which the object moves while touching the surface. To prevent wear during this contact, a lubricant is usually applied to the surface of the magnetic disk. However, this! It is sufficient if the IW1 agent is applied in an appropriate amount, but there are many cases where it is too much or too little.

If it is too small, the original purpose of preventing wear cannot be achieved, and if it is too large, the slider will be attracted to the magnetic disk when it stops, and when it starts moving, a large force will be applied to the gimbal that supports the slider, making it difficult to maintain the normal flying posture of the slider. It may disappear. If such a situation occurs, it will lead to destruction of the head portion.

For this reason, in order to avoid damage to the head due to the above-mentioned adhesion, efforts are currently being made to make the slider even smaller and lower the floating blade to relatively reduce the pressing force of the gimbal against the magnetic disk. ing. However, if the slider is made too small, as mentioned in (1) above,
At present, it is extremely difficult to design a slider because the influence of disturbances on the receiver increases and the resistance to large undulations on the magnetic disk surface deteriorates.

Furthermore, in order to solve the above-mentioned problems, a combination of two large and small gimbals has been proposed.

(Refer to Japanese Patent Publication No. 44-186674) This is a system in which two gimbals are divided into one for following large undulations and one for following small undulations.

However, even with such a structure, the slider cannot basically avoid unexpected abnormalities such as protrusions or dust on the surface of the magnetic disk, and its design is difficult.

This invention was made by focusing on the above-mentioned conventional problems, and has no difficulty in design, can follow both large and small undulations of the magnetic disk, and can always maintain a stable surface on the magnetic disk even with a low-flying blade. It is an object of the present invention to provide a floating magnetic head device which can float upward and avoid sudden protrusions on the surface of a magnetic disk.

[Means for solving problems]

In order to achieve this object, the present invention provides a slider equipped with a biasing member toward the recording medium side and having a magnetic head section;
A condensing means for condensing light onto the surface of the recording medium is attached to each support, and a signal detected by the distance detecting means moves the support in a direction toward and away from the recording medium. The solution to this problem was to provide a means of transportation.

[For production]

The light focused through the focusing means is reflected on the surface of the recording medium that is moving relative to the slider, and the distance detecting means that receives this reflected light detects the distance between the slider and the recording medium. Upon receiving the detection signal, the moving means moves the support so that this distance becomes appropriate.

〔Example〕

Hereinafter, the present invention will be described in detail based on the drawings.

FIG. 1 shows an embodiment of the present invention, and its configuration will be explained first. One end of a leaf spring 3 is attached to the fixed end 1 on the side of the main body of the magnetic recording apparatus, and a support R5 is provided vertically on the lower surface of the other end of the leaf spring 3. An objective lens 7 as a condensing means is mounted inside the support tube 5, and at the lower end of the support tube 5, a gimbal (biasing member) 9 consisting of a plate spring having a downward biasing force in the figure is attached. installed and further,
At the center of the lower end of this gimbal 9, a slider 11 made of glass, sapphire, or the like that transmits light is mounted, and is equipped with a magnetic head portion (not shown). That is, the leaf spring 3 and the support tube 5 constitute a support body for the objective lens 7 and the gimbaled slider 11. Further, a light passing hole 3a is formed in the leaf spring 3 above the objective lens 7, and the objective lens 7 focuses the light passing through the light passing hole 3a on the magnetic disk 17 during normal operation of the apparatus. It is installed in the position where it is tied.

A coil 13 is wound around the outer periphery of the support cylinder 5, and a cylindrical magnet 15 is disposed on the outer periphery of the coil 13. Further, the coil 13 is supplied with a current obtained by amplifying a signal from a distance detecting means to be described later, and the support cylinder 5 moves up and down by the electromagnetic force between the coil 13 and the magnet 15. That is, the coil 13 and the magnet 15 constitute a moving means.

A magnetic disk 17 is disposed below the slider 11, and as the magnetic disk 17 rotates, it moves relative to the slider 11 in the direction of the arrow (right) in the figure. It is configured to levitate against the surface.

On the other hand, in front of the laser 19 that emits light that is focused by the objective lens 7 and reflected on the magnetic disk 17 is a collimator lens 21 that collimates the light, and further in front of the laser 19 is a collimator lens 21 that collimates the light.
Half mirrors 25' inclined at an angle of 5 degrees are provided. The half mirror 25 has a reflecting mirror on its upper left side in the figure. In other words, this half mirror
25 allows the light emitted from the laser 19 to pass through and travel straight, and reflects the light from the opposite side to the laser 19 upward.

Near the intersection of the optical path 23 and the central axis of the objective lens 7, that is, directly above the objective lens 7, there is a mirror 27 that reflects the light from the laser 19 toward the objective lens 7.
It is arranged parallel to 5.

In addition, directly above the half mirror 25, there is a half mirror 2.
A photodiode 29 is provided as a distance detecting means for receiving light reflected by the mirror 5, and a cylindrical lens 31 is provided between the photodiode 29 and the half mirror 25.

The photodiode 29 detects the differential output of the light reflected by the half mirror 25 by dividing its light-receiving surface into four parts, and this detection signal is amplified by an amplifier (not shown) and fed to the coil 13 as a current. ra, ru.

Next, the operation of the floating magnetic head device configured as described above will be explained. As the magnetic disk 17 rotates, it moves in the direction of the arrow (right) in the figure with respect to the slider 11. This movement causes the slider 11 and the magnetic disk 17 to
Air flows in from the left direction in the figure between the slider 11 and the slider 11, causing the slider 11 to slightly float above the magnetic disk 17.

On the other hand, the light emitted from the laser 19 is turned into a forward beam by the collimator lens 21, passes through the half mirror 25, reaches the mirror 27, is reflected there, changes its direction by 90 degrees, and heads toward the objective lens 7. Here, if the distance between the slider 11 and the magnetic disk 17 is maintained appropriately, the light collected by the objective lens 7 will be focused on the magnetic disk 17. The light focused on the magnetic disk 17 is reflected here, follows the same optical path as when it was incident, is reflected by the mirror 27 and the half mirror 25, and reaches the photodiode 29. Since the focus remains fixed at , the so-called spot diameter remains unchanged.
No differential output is generated by the photodiode 29, and therefore no current is supplied to the coil 13, so the appropriate distance between the slider 11 and the magnetic disk 17 remains maintained.

Also, if there is an abnormality such as a protrusion on the magnetic disk 17, the magnetic head (
When the slider 11) approaches, the distance between the surface of the magnetic disk 17 and the objective lens 7 changes, and the light focused by the objective lens 7 is no longer focused on the magnetic disk 17. The diameter of the light spot becomes larger.

The light having a large optical spot diameter is reflected on the magnetic disk 17, further reflected by the mirror 27 and the half mirror 25, and passes through the cylindrical lens 31.

The light having a large spot diameter that passes through the cylindrical lens 31 becomes an oval shape and reaches the photodiode 29 as it is. Since the light receiving surface of the photodiode 29 is divided into four parts,
When the oval light enters this light receiving surface, the photodiode 29 detects it and generates a differential output.

This detection signal is amplified by an amplifier (not shown) and the coil 1
3 as a current, and a force of 78!1 is generated in the coil 13. Due to this electromagnetic force and the electromagnetic force of the magnet 15, the support cylinder 5, together with the objective lens 7 and the slider 11, is moved in parallel upwardly if the abnormality on the magnetic disk 17 is a convex portion, and downwardly if it is a concave portion. This movement continues until the light that has passed through the objective lens 7 is focused on the magnetic disk 17. That is, by controlling the current value supplied from the photodiode 29 to the coil 13, the magnetic disk 17 is always brought into focus. In other words, the flying height of the slider 11 relative to the magnetic disk 17 is always kept constant.

When optically detecting the distance between the magnetic disk 17 and the slider 11 in this way, it is possible to control this distance with an accuracy of 1 μm, and therefore the condition for the slider 11 and gimbal 9 is to It would be good if it could follow the vertical movement. Therefore, while the condition for the conventional floating magnetic head was that it had to follow a vertical movement of 100μ, the following condition for the slider 11 of the present invention is reduced to 1/100 of that, and the gimbal The pressing force exerted by the slider 9 on the slider 11 is also significantly reduced, and the floating blade of the slider 11 can also be made smaller, allowing the slider 11 to be made smaller. Also, magnetic disk 1
7 starts rotating, by controlling the current flowing through the coil 13, the slider 11 is raised significantly above the surface of the magnetic disk 17 before starting, and after the rotation becomes completely steady, the slider 11 is moved magnetically. disk 17
Furthermore, when the magnetic disk 17 stops rotating, the current supply to the coil 13 is continuously turned off until the rotation stops, keeping the slider 11 floating. And non-contact operation of the slider 11 to the magnetic disk 17 when stopped is possible,
Friction of the magnetic disk 17 can be avoided.

Generally, in a floating magnetic head, the entire head must be made to float and move at high speed in the track direction relative to the magnetic disk, so it is better for the weight of the entire head to be light. From this point of view, the present head configuration may be larger than the conventional head, but since only the optical system surrounded by the broken line in the figure can be separated from the head body, the objective lens 7 and its movement means are added to the head part. However, it does not pose much of a problem, and the weight can be further reduced by using a plastic lens for the objective lens 7 or using a high-performance 3a+-Co magnet.

FIG. 2 is a schematic diagram of another embodiment. In this embodiment, the same components as in the previous embodiment are given the same reference numerals to simplify the explanation. In this embodiment, the slider 11 is placed behind the incident position of the light on the magnetic disk 17 through the objective lens 7 (assuming that the slider 11 is moved to the left in the figure with respect to the magnetic disk 17). By doing so, the light incident position can be positioned in front of the slider 11, and abnormalities in front of the slider 11 can be detected quickly. In this case, since the slider 11 is out of the light path, it does not need to be transparent as in the previous embodiment; it may be made of a conventionally used ferrite material. Other configurations and operations are similar to those of the previous embodiment. Note that the optical systems such as the laser 19 and photodiode 29 and the means for moving the support tube 5 shown in FIG. 1 in the above-described embodiment are omitted here.

The head section of the present invention may be, for example, an inductive bulk head, a thin film head, or a magnetoresistive (MR) head.
It can be applied to all types of heads, optical reproduction heads, etc., and does not stipulate the principle or structure of the head.

〔Effect of the invention〕

As explained above, according to the present invention, the variation in the distance between the recording medium and the slider is suppressed to within a range of 1 μl or less using the detection means of the optical system, and is kept constant at all times, resulting in the following effects. .

That is, since the slider only needs to be able to follow up and down movements of approximately 1 μm, the following conditions for the slider of the present invention are reduced to 1/100 of the 100 μm followability required in the past. As a result, the force required to press the slider by the biasing member is significantly reduced, and the floating blade of the slider can be made smaller, making the slider smaller and lighter.The resonant frequency can also be increased, allowing the slider to follow abnormalities on the surface of the recording medium. Sexuality also improves.

As a result, the slider can sufficiently follow both large and small undulations of the recording medium. (2) Since the pressing force of the slider against the recording medium side is small, the head will not be damaged even if the slider comes into contact with the recording medium, and the slider will not be attracted to the recording medium surface when the device is stopped. This makes it difficult to cause damage to the head due to adsorption.

Therefore, by using the floating magnetic head of the present invention in combination with, for example, a magnetic disk, it can be used in fields that use high-density magnetic recording, that is, information processing equipment that uses computers and the like, and broadcasting, audio, and video equipment that uses audio and video recording. Application 1 will have a great effect on improving performance and reliability.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a floating magnetic head device according to an embodiment of the present invention, FIG. 2 is a schematic diagram of a floating magnetic head device of another embodiment, and FIG. 3 is a diagram of a conventional floating magnetic head device. 1 is a schematic configuration diagram of a floating magnetic head device. 3... Leaf spring (support body) 5... Support cylinder (support body) 7... Objective lens (light condensing means) 9... Gimbal (biasing member) 11... Slider 13... Coil (moving means) 15... Magnet (moving means) 17... Magnetic disk (recording medium) 29... Photodiode (distance detecting means) 1'Bowl・
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Claims (1)

[Claims] A slider equipped with a biasing member toward the recording medium and having a magnetic head section and a light condensing means for concentrating light on the surface of the recording medium are respectively attached to a support, and the light is reflected on the surface of the recording medium through the condensing means. distance detecting means for detecting the distance between the slider and the recording medium by receiving the light, and a moving means for moving the support in a direction toward and away from the recording medium based on a signal detected by the distance detecting means. A floating magnetic head device characterized by: