JPS6035347A - Pickup - Google Patents

Abstract

PURPOSE:To prevent the influence of an external disturbing magnetic field and eliminate noise in reproduction by providing a pickup itself with a magnetic field generating mechanism and applying a constant magnetic field to a recording medium, and reading the difference in magnetic resistance between a magnetic part and a nonmagnetic part and performing reproduction. CONSTITUTION:The whole pickup is formed of a magnetic body 31, and a signal detection end part 37 consists of extremely small end parts 35 and 36 and a gap 33. The length (a) of the detection end part 37 is made equal to or shorter than the length of the shortest bit on a disk. Further, a permanent magnet 32 is provided at the center part of the magnetic body 31 as the means which generates a constant magnetic field. Consequently, the detection end part 37 is positioned at a projection part on the disk surface where a pit 2 is absent, both extremely small end parts 35 and 36 contact a magnetic body layer 3 to decrease the magnetic resistance of the detection end part 37, and when only the end part 35 reaches a pit 2 and leaves the magnetic body layer 3, the magnetic resistance decreases abruptly. Thus, the magnetic resistance at the detection end part 37 increases or decreases abruptly according to whether the pit 2 corresponding to a signal is present or not, and the signal is detected by the coil 34.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an information signal recording and reproducing method for magnetically recording and reproducing information signals.

In recent years, various methods have been proposed for recording information signals such as video signals at high density on disks or magnetic tapes and reproducing them.

For example, as video disc systems, 1 mechanical compression method, 2 capacitance method, 2 optical method, etc. are known, and signals are recorded and reproduced using different methods.

Now, in order to deepen the understanding of the present invention and to clarify the differences between the above six methods and the present invention, the above six methods will be briefly explained.

(Q mechanical compression force type For example, a spiral ■-shaped groove is formed on the surface of a disk with a thickness of 12 rnm to 0.15 mm, and a signal (FM modulated video signal or audio signal ) is engraved on it, and the regenerated Pi Sofa rug is called a piezoelectric type, and piezoelectric ceramic is formed on 1 and 2 parts of the diamond sled needle, and these are fixed to the tip of the cantilever.The disk rotates. Then, the repulsive force of the unevenness in the bay is transmitted to the piezoelectric ceramic through the diamond needle, converted into an electrical signal, and reproduced.

(Static capacitance method) A diamond or zaphire needle has an electrode, and a floating diode or sphincter made of conductive resin is used as the other electrode, and these two electrodes form a capacitor, which is formed on the disk surface. By using the fact that the capacitance of this capacitor changes depending on the signal received, the signal is converted into an electric signal using a high frequency method and the signal is reproduced.

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The disc surface has no grooves and is formed into a spiral shape.
There is a Vi (D method and Power 1 method) that reads signals using the change in content capacity depending on the presence or absence of Pisoto.

(2) Optical method A spiral pattern is formed on the surface of the original disk, and a signal is recorded depending on the presence or absence of this pattern. The playback Pinocqua knob does not touch the disc, irradiates the disc with a beam of light, and receives the reflected (or transmitted) light from the disc with a weak bit on the photoelectric conversion element, causing a change in current. It is read as

The video disc system as described above cannot record data arbitrarily like a general audio record, and has only the function of playing back discs on which signals have already been recorded.

On the other hand, there is a so-called magnetic recording and reproducing system ζ which uses the magnetization of a magnetic material to arbitrarily record and retrieve the pleasure μ signal, and is widely applied using a magnetic disk or magnetic tape. Two typical application examples of high-density recording of information using such an air-repellent recording and reproducing method are as follows: - A magnetic disk for video signal recording and reproducing A metal disk with a ferromagnetic layer on the surface is used. Video signals can be recorded and reproduced arbitrarily, but the recording density is approximately 0 sec. There is no other choice.

■Video tape recorder (■T1t) This uses a plastic tape with a ferromagnetic layer on its surface, magnetizes information signals with a rotating blade, records them, and plays them back. It is planned.

In addition to the above two application examples, these recordings are performed by magnetizing magnetic particles in a ferromagnetic layer provided on a disk or tape.

The present invention is essentially different from the above-mentioned conventional recording and reproducing method,
The present invention provides a pickup based on a completely new recording and reproducing method capable of reproducing a recording medium on which information signals are recorded with high density.

That is, although the recording medium to be reproduced according to the present invention has a magnetic layer on its surface, it does not electromagnetically magnetize this magnetic layer to record signals as in the prior art, but instead J--The magnetic layer is essentially made into a magnetic part and a non-magnetic part by embedding or chemical treatment, and signals are recorded by repeating the magnetic part and the non-magnetic part.

Further, the pick-up knob according to the present invention is made of a magnetic material, and a coil is wound around the magnetic material, and the pick-up knob itself has a magnetic field generating function such as a permanent magnet. It is.

The recording medium on which the signal has been recorded as described above is slid over the above-mentioned pickup, and the difference in magnetic resistance between the magnetic sound part (σ) and the non-magnetic part on the recording medium surface is detected using a vinyl knob. Taking the signal as a change is 1:) a3t.

The pi-sofa knob of the present invention is generally based on the principle as described above, and the present invention will now be described in detail with reference to the drawings.

First, a recording medium to be reproduced by the pisobuanobu of the present invention and recording of signals on this recording medium will be explained.

The recording medium has substantially magnetic j<
l-min and non-magnetic portions are formed alternately in accordance with the signal, and the magnetic portion has a non-magnetized configuration. Although the shape of the recording medium can be any shape such as a disk shape, tape shape, or card shape, a disk will be explained here for the sake of simplicity.

FIG. 1 shows an example of the disk of the present invention, (
A) is a perspective explanatory view thereof, and (B) is a cross-sectional explanatory view thereof. The disc base (1) is made of, for example, the same vinyl chloride resin as that used in ordinary audio discs, and has uneven pits (2) formed in a spiral (or concentric circle) shape. Recording signals in such a shape has already been applied to the optical system or VID system of the video disc system described above.

The disk of the present invention is characterized in that it further has a thin magnetic layer (3) on the surface of the disk base (1) on which the uneven pins [2] are formed. What should be noted here is that even if the magnetic layer (3) is formed, the disk surface still maintains its uneven shape. Further, this magnetic layer (3) is maintained in an unmagnetized state.

As a result, in relation to the pickup described later, the focus portion (recessed portion) essentially becomes the non-magnetic portion (5), and the other portion becomes the (IB magnetic portion 4).

Further, although the above-mentioned disk is a grooveless disk like the optical method and the VI-T I) method, the disk according to the present invention has a spiral or concentric ring on the disk surface as seen in the mechanical compression method and the RCA method. Even those with V-shaped guide grooves are suitable. In this case, a concavo-convex signal corresponding to the information signal is formed on the surface of the guide groove, and if a magnetic layer is provided on the surface without being magnetized while maintaining this concave-convex shape, the convex portion Signals are recorded on the magnetic part and the concave part as a non-magnetic part.

In manufacturing a disc in which signals are recorded in the uneven shape as described above, in the case of a non-grooved disc, a glass master on which a photosensitive resin or metal thin film is formed is used. A thin metal film is exposed to a laser beam and hardened or evaporated to form a bit to record a signal, and from this glass master father, mother, and standby
The mold is then returned, and a disk made of vinyl chloride resin or the like is manufactured using a stamper press or injection. On the other hand, when manufacturing a disk with a figure-7 guide groove, a lacquer disc or a copper disc is used as a master, and this master is used to record the signals to be recorded using a V-shaped cutting blade such as a diamond or the like integrated with a piezoelectric ceramic. It cuts in an uneven shape by moving up and down in response to the movement. In this case, as in the case of grooveless disks, disks made of vinyl chloride resin or the like can be manufactured in large quantities from the stand bar.

If a magnetic layer of nickel or the like is formed on the surface of the disk on which signals are recorded with or without pits or with uneven shapes by plating, vapor deposition, sputtering, etc., and this magnetic layer is maintained in an unmagnetized state, A disk of the present invention can be obtained.

A disk substrate with signals recorded in an uneven shape on its surface is prepared using a stamper, and a magnetic layer is uniformly provided on the surface of the disk substrate, so that magnetic portions and non-magnetic portions are substantially alternated. Forming a magnetic layer on the disk substrate 01) and recording signals thereby has the advantage of being mass-producible, but as shown in FIG. (13) may be formed into a magnetic part 04) and a non-magnetic part (15), or the entire disc may be formed as shown in Fig. 6 without using a disc base made of vinyl chloride resin or the like. It may be made of a magnetic material (21) and have a magnetic portion (23) and a non-magnetic portion (24) formed therein. Of course, the magnetic layer is not magnetized in any of the embodiments.

It is also possible to coat the disk surface with a thin film of plastic or the like, which can reduce the frictional resistance with the pickup (described later) and reduce wear on both the pickup and the disk.

In the above explanation, signals are recorded using the magnetic and non-magnetic parts by utilizing the uneven shape of the disk surface, such as the presence or absence of pits. Magnetic portions and non-magnetic portions may be alternately formed on the disk surface so that a significant difference in magnetic resistance appears in relation to the disk, and signals may be recorded with the magnetic portion in a non-magnetized state. It goes without saying that such recording can be applied not only to disks but also to cards, tapes, and the like.

Next, the magnetic pickup of the present invention will be described. For convenience, in the following description, a disk having a pit array as shown in FIG. 1 will be used as a recording medium to be reproduced.

FIGS. 4 to 61 show diagrams of the principle of the pickup of the present invention. All of them are entirely formed of a magnetic material (3), and both ends G (36) of this magnetic material (31) are extremely small and face each other, and these opposing microscopic ends (3
A gap (33) is formed by ω (3G).

The minute end (3ω (3G)) and the air gap (33) constitute a signal detection end (37), and this signal detection end i,
37) comes into sliding contact with the disk surface and moves relative to it, thereby detecting the signal recorded on the disk.

Since the information signal to be detected is recorded by repeating magnetic and non-magnetic parts (in this case the presence or absence of pits), the dimension a of the disk contact surface of the signal detection end (37) is extremely important. Te(ru)

That is, the length a of the disk contact surface of the signal detection end (37) in the disk rotation direction is large enough to detect the presence or absence of pits, that is, the length of the shortest pit formed on the disk. The value shall be equal to or less than that. Specifically, if the length of the shortest via 1□ is 05 μIn, the dimension a of the disk contacting surface of the signal detection end (37) will be 05 μm or less. This will be explained further later.

Further, a coil (34) is wound around the magnetic material (311) for extracting changes in magnetic flux as changes in current.

Furthermore, the pickup of the present invention is characterized by:
The pickup itself is provided with means for generating a constant magnetic field. Typical examples of means for generating a constant magnetic field include a permanent magnet (magnetic material 01 with three functions) installed in the center as shown in Figure 4, and a coil as shown in Figure 5. (34) with high frequency bias (4
0), etc., where the magnetic field can be generated.

In this way, the pink-up of the present invention is a permanent magnet (321
etc., a constant magnetic field is obtained, and the gap in the signal detection end (37) is made to have a large and constant magnetic resistance.

In addition, since the signal detection end (37) is very fine, the contact area with the disc is small, which will accelerate the wear of the disc and pickup. It is coated with a protective material such as non-magnetic metal to increase the contact area with the disk and reduce the pressure.
Increases the wear resistance of both the disc and pickup,
In addition, it is preferable to eliminate protrusions and make the structure strong.

A method for reproducing a disc on which signals are recorded using such a pickup will be described below.

Theoretically, it is possible to detect signals even if there is a slight air layer between the pickup and the disk, but here we will use a pisoqua amplifier like the mechanical compression method or capacitance method explained in the conventional technology. and the disk are assumed to be in contact with each other. The disk to be reproduced is one without grooves as shown in FIG. 1, and in which signals are recorded by substantially alternating magnetic and non-magnetic portions in rows of pits.

Here, it is assumed that the disk rotates in the direction of the arrow shown in FIGS. 4 to 6.

As shown in Figure 4, the signal detection end 07+ of the big amplifier
When is located at the part (convex part) without B, G (2+) on the disk surface, both of the minute ends (35) (36J) are in contact with the magnetic layer (3) of the disk, and the nearby More magnetic flux passes through this magnetic layer, and the magnetic resistance becomes smaller.

Next, when the disk rotates slightly and, for example, as shown in FIG. Department (37
) the magnetic resistance increases rapidly.

As the disk rotates in this way, both minute ends (351 (361 separates from the magnetic layer (3), and finally one minute end 65) reaches the next convex portion (Fig. 6). ).

Furthermore, the disk turns and the minute part of both swords t3E again.
+) When (36) reaches the convex portion and comes into contact with the magnetic layer (3), the magnetic resistance decreases.

Here, the length of the disk contact surface of the pickup signal detection end (137+ in the disk rotation direction) is set to be equal to or less than the length of the bit (as mentioned above, the minute end (35) (36) is a result of consideration so that the signal detection end (37) can be located in the bit part (concave part) (2) without touching the magnetic layer (3) of the convex part. will be understood.

, In this way, the minute end (3) of the signal detection end (137)
51 (36) are both located on the portion where there is no pit (2), that is, on the convex portion.

2) When in contact with the magnetic layer (3) of the disk, the magnetic resistance applied to the signal detection end (37) becomes small, resulting in a very small end! When either one or both of the 3" SIC, 36) is away from the magnetic layer (3), the magnetic resistance increases.

As described above, as the disk rotates, the magnetic resistance applied to the phantom detection end (37) changes depending on the presence or absence of the pier 1' (2+) formed in response to the signal, and the pickup The magnetic flux passing through the coil c,'+1+ wound around the magnetic material (3+) changes, and the coil (34)
The signal is detected as a change in the current induced in the

Note that when reproducing such a grooveless disc, tracking can be performed in the same way as the optical method of the Piteotisk system.

The above explanation has been made based on the assumption that a disk on which signals are recorded using pit rows is played back, but the same principle applies to disks with guide grooves, cards, tapes, etc. where signals are recorded using magnetic and non-magnetic portions. recorded media can be played back.

As described in detail above, the present invention records information signals by alternately providing magnetic portions and non-magnetic portions without being magnetized on the surface of the recording medium, and the recording medium in which such recorded information is recorded. A big-up that applies a constant magnetic field to the surface, reads the difference in magnetic resistance between the magnetic and non-magnetic parts, and reproduces the signal as a change in current.It is a method of recording and reproducing known information signals. It is completely different from the original, and has the following great effects.

First, although the recording medium has a magnetic layer L5, 1
First, compared to conventional magnetic recording and reproduction, since the recording is based on physical shape rather than magnetization, signal destruction due to external disturbance magnetic fields or heating is less likely to occur.Furthermore, since recording is not based on magnetization, graininess is less likely to occur. The -L limit of the recording density that was caused by this is eliminated, and the noise caused by this graininess at the time of coexistence is also eliminated.

Furthermore, since magnetic reproduction is used, the reproduced signal is not degraded by fingerprints, airborne potential substances, oils and fats in airborne objects, etc.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention, and FIGS. 1 to 6 are explanatory diagrams of the recording medium of the present invention, and FIGS. 4 to 6 show the recording medium of the present invention. FIG. 2 is an explanatory diagram showing the reproduction principle used. (1) (Mark/Disk base (2) 02) (2 discharge Bi-Soto (3) (131c, 7]) - Magnetic material t4) 04+1
23+・Magnetic part (5) (15) f24) Non-magnetic part (31)・Magnetic body (33+・Void part (34)・-Coil patent applicant Toppan Printing Co., Ltd. Representative Kazuo Meiki Figure 1 (a) Figure 1 (C1) Figure 5

Claims (1)

[Claims] 1) Reproducing recorded information signals by sliding on the surface of a recording medium and providing substantially magnetic portions and non-magnetic portions alternately on the surface of the recording medium without being magnetized. In the pickup for generating a signal, the entire body is made of a magnetic material, and a signal detection end is formed by making both ends of this magnetic material small and facing each other with a slight gap, and this signal detection end The length of the contact surface with the surface of the recording medium is set to be equal to or less than the length of the magnetic portion or non-magnetic portion of the surface of the recording medium, and the magnetic material induces a current according to changes in magnetic flux. A magnetic field generating means is provided to generate a constant magnetic field while a coil is wound around the magnetic field, and changes in magnetic flux caused by repeated contact and disconnection of the signal detection end with the magnetic portion of the recording medium are detected by the current. Take it out as a change,
A pickup characterized by reproducing signals. 2) The pick amplifier according to claim 1, wherein the periphery of the signal detection end is covered with a protective material such as glass, resin, or non-magnetic metal to widen the disk contact area.