JPS6243833A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To permit magnetic recording and reproduction over a wide frequency range at a high density by forming the 2nd magnetic layer in which magnetic particles having large coercive force are oriented in a vertical direction or non-oriented on the 1st magnetic layer in which the magnetic particles are oriented in the longitudinal direction in such a manner that said layer is thinner in thickness than the 1st magnetic layer. CONSTITUTION:The acicular magnetic particles of, for example, iron oxide having the coercive force as low as 200-300Oe are coated on a base 1 and thereafter the 1st magnetic layer 2 subjected to the intra-surface orientation is formed thereon. The planar magnetic particles of, for example, barium ferrite having about 500-1,000Oe coercive force larger than the coercive force of said magnetic layer 2 are coated thereon and thereafter the 2nd magnetic layer 3 subjected to the vertical orientation or non-orientation is formed thereon. The thickness of the magnetic layer 3 is preferably <=1mum. A long wavelength component is recorded by a longitudinal recording system to the magnetic layer 2 and therefore, the demagnetization field is small. On the other hand, the short wavelength component is recorded by a vertical recording system to the magnetic layer 3 and therefore, the demagnetization field is small. The recording and reproduction with the small demagnetization field are thus made possible from the short wavelength component to the long wavelength component.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a magnetic recording medium, and more particularly, to a magnetic recording medium that is capable of recording and reproducing from short wavelengths to long wavelengths by configuring magnetic powder in two layers.

(Prior Art) The recording density of magnetic recording has become significantly higher due to the development of magnetic materials, base materials, magnetic heads, and the like. In particular, the recording density of consumer magnetic recording and reproducing devices is becoming higher and higher, and the recording wavelength tends to be shorter.

Conventionally, in magnetic recording, a so-called longitudinal recording method (in-plane recording method) in which the magnetic layer of a tape is magnetized in the longitudinal direction or in-plane direction has been widely used. However, it is known that in this longitudinal recording method, as the recording wavelength increases, the demagnetizing field increases, the reproduction level decreases, and high-density recording is not adversely affected.

In order to eliminate such adverse effects, there is a so-called perpendicular recording method in which the magnetic layer is magnetized in the perpendicular direction. This perpendicular recording method has the characteristic that the recording wavelength is short and the demagnetizing field becomes smaller as the recording density becomes higher. However, in order to completely perpendicularly magnetize the magnetic layer, it is necessary to use an auxiliary magnetic excitation type perpendicular head.

Since this auxiliary magnetic excitation type perpendicular magnetic head has a structure in which a magnetic medium is sandwiched in the thickness direction of the magnetic layer, the structure is complicated and it is difficult to apply it to a rotating magnetic head such as that used in a VTR, for example.

Therefore, it is necessary to use the ring-type magnetic head that has been used in the past. -L
j: When recording Li, vA Takeshinchi 1 sentence, 1 CI (1600g J direction I6 east component is large, so it is saturated (餞中-♀ji-ro's human P lettuce 1~) Using 11?-'b j
l'ill'l Ia facing west 11 1), the recordable wavelength ε) is naturally limited;
L! Record 11I) 1 was completed 1.1?-).

(The invention solves the 6 dosing problem +:, i > K1 recording 1) Equation Ci, the recording wavelength of t is applied) or <4 C, the demagnetizing field becomes 11 (1.1 Therefore, the high frequency components can be recorded sufficiently if the high frequency components are recorded. If the structure of the ring-shaped magnetic head l'-C is repeated, and if it is 1J41, then the low frequency components will be sufficiently recorded i1+'l.
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For this reason, for example, the frequency of 1117 recordings is 1117, like V-1. When trying to record and play back as wide a range as possible, there is a problem with video and high-i41 records (1, which adversely affects the S/N comparison and deteriorates the S/N ratio). 1st step of the solution) This invention solves the problem in question 1.
(11 (40 base 10, 1 grain 1, 1 grain) direction (
This orientation! ! , -: 1st pregnancy) form 1 size (J rod 1t, this ゑ11σ) 141 il + deal F
The RIB has a length t'1 grain, which is oriented in the direction of 11, and 31 has no orientation. 1. 1st (11 of 6 bamboo layers)
]Sa J, thin shape (I\matako 4 characteristics every l↑
Ilha 11th record TA! Body (,,li,l,jro1゜(Example) Figure 1 shows the nitric gas record of the present invention, V, body configuration '6' +]
' Power?00~3000
If e is low, for example, 1111 grains of iron oxide are in contact with each other, and the first magnetic layer 2 with rnlnl plane orientation is formed. For example, after applying the barium noi 1- root-like pregnant particles of coercive force from 500 to 10,000 f!
A layer 3 with vertical orientation or (1 non-orientation, 20) is formed.

The coating thicknesses of these 1lfi layers 2, 3, and 3 are respectively Tatsumi='U, 135), 14f t'l Ig
2 Ha<1″L coming (J) Example work 1.f m ki T −
1 ((eye) may be the same AIN as the layer thickness, and there is no particular limitation on the 1 warp. - Gutsumagnetic↑'l IH30) 11 thickness is 1
1°, which is preferably 1 ITll or less, is actually applied on the opposite side (95 side) of the magnetic layers 2 and 3 of the base 1.

In addition, apply it to the 1st and 1st eye of L. [The orientation of the particles varies, and in order to align the orientation, combine the magnetic particles with a solvent, a charged V'JII agent, etc.) While the solvent, etc. is still hardening, move the tat' to the desired horizontal direction with respect to the IW and 7J directions of the layer.
7J facing Wl 'Ju wo I) +j T 'a↑ノ+ a child wo water]! After arranging them in one direction, dry them.

Non-orientation can be achieved by curing the solvent, etc. without applying such ++i to 1). 3. The mechanism for recording on the magnetic recording body of the present invention having the configuration as described in 1 below with a ring-type magnetic head is explained in Figure 2. Identical constituent parts will be explained using the same symbol ";4".

4 is ring type W! With the air head, only the vicinity of the pump section 5 is shown - (6 is for the ring-shaped magnetism, the throat 4 is [6 lines, 8 is the run of the magnetic recording medium?i1] Direction 4-Small 1
Kuin C. Yes. From the figure, we can see that for the second magnetic layer 3, the lines of magnetic force 6 are (4 + 1, 130
112 f.

There are many components perpendicular to the direction, ((eye'F PA3 is tI
There are many parts that are magnetized towards the ill'1 horn, and a little
(There are some parts that are turned into 141 in the vertical direction. In the first (41 bamboo layer 2 +,: 241. In this case, the magnetic 11 layer 2 uses the long recording method, and...↑
With 1 layer and 3, the recording system became 1 East iI + 1, which meant that a kiki-recording medium with the features of the image recording system was created.

That is, since the M layer 2-U-i is recorded using the longitudinal recording method jC, the demagnetizing field is small.On the other hand, the magnetic layer 3 is recorded with the short wavelength L (the component is perpendicularly recorded). Since recording is performed, the demagnetizing field is small (), and recording and reproducing can be performed with a small demagnetizing field from the 0 wavelength component to the long wavelength component.

Commonly used Fully [・(Maximum magnetic flux density of the sealing head is 4500 Gauss, -'A・Tsubu q is 0)
．． When the recording depth is 3 to 0.5 μm, the relationship between the recording depth (1) and the coercive force 11c is as shown in the table below.

However, k-t-1s/1-lc, Hs is the saturation magnetic field strength of the tape.From the table above, when recording with a ferrite magnetic head, the coercive force is 200 to 3000e at a depth of 1.5 μm from the surface of the magnetic tape. Since it can be understood that the first Iat! The coercive force is set to this value so that the first layer 2 can be sufficiently magnetized.

Also, since the magnetic layer 3 records short wavelengths,
The effective thickness of the magnetic layer is said to be 1/4 to 115 of the recording wavelength, and a thickness L of the magnetic layer 3 of L 111 m or less is sufficient.

Furthermore, since the maximum saturation magnetic flux density of the magnetic layer 2 is too large, it is more effective to use metal magnetic particles with low coercive force, for example, because the magnetic permeability increases compared to using iron oxide magnetic particles. Since metal magnetic particles are easily oxidized, using an oxide for the magnetic layer 3 also protects the magnetic layer 2.

(Effects of the Invention) The magnetic recording medium of the present invention enables recording and writing from short wavelength components to long wavelength components without a demagnetizing field using a ring-type magnetic head with a simple structure. It has the feature of being able to record and play back.

Therefore, if the magnetic recording medium of the present invention is used in, for example, a VTR, recording and reproduction with excellent video and audio characteristics is possible.

[Brief explanation of drawings]

FIG. 1 shows 1, 1. of the magnetic recording medium of the present invention. FIG. 2 is a sectional view showing the I configuration, and FIG. 2 is a diagram illustrating a mechanism for recording on the magnetic recording medium of FIG. 1... Base, 2... First magnetic layer (in-plane orientation),
3... Second magnetic FJ (perpendicular alignment or non-alignment), 4
...Ring type head, 5... Gap, 6... Line of magnetic force, Δ... Arrow indicating the running direction of the magnetic recording medium. ．． 4 X - 2nd station 1;.

Claims (1)

[Claims] A first magnetic layer in which magnetic particles are oriented in the longitudinal direction is formed on a base of a non-magnetic material, and magnetic particles having a larger coercive force than the magnetic particles are oriented in the vertical direction on top of the first magnetic layer. Alternatively, a magnetic recording medium characterized in that a non-oriented second magnetic layer is formed to be thinner than the first magnetic layer.