JPS6061901A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To attain transmission of a DC component with low working accuracy by using the photodetecting and light emitting elements set to a rotary shaft of a rotary head or to a stator on an extended line of said rotary shaft together with other photodetecting and light emitting elements which are always connected optically to the first photodetecting and light emitting elements respectively. CONSTITUTION:In a record mode a light emitting element 34 is driven by a record signal, and the light of the element 34 is received by a photodetecting element 35. Then the record signal is extracted and a signal current is flowed to a rotary head to perform recording. While in a reproduction mode a light emitting element 33 is driven by a reproduction signal given from a rotary head. The light of the element 33 is received by a counter photodetecting element 36, and the reproduction signal is extracted. The element 33 revolves round the rotary shaft of a rotary head disk, and the center axis of the element 33 passes through the element 36. Thus the incident angle of the light to be given to the element 36 is varied by revolutions. The element 35 also has the same characteristics. Then both elements 33 and 34 are set extremely close to the rotary shaft. In such a constitution, a DC component can always be transmitted regardless of the working accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a rotating head helical scan type magnetic recording/reproducing device, and more particularly to a coupling method between a rotating head and a signal processing circuit.

[Technical background of the invention and its problems]

In a rotating head/helical scan type magnetic recording/reproducing device, a signal current is passed through the head that rotates once,
Rotating transformers are mainly used to extract signals. FIG. 1(a) is a schematic sectional view of a rotary transformer conventionally used for coupling a rotary head and a signal processing circuit, and FIG. 1(b) is a simple equivalent circuit thereof. A rotor 12 attached to the rotating shaft 11 of the motor and a stator 14 fixed to a fixed cylinder 13 face each other with a very small gap 15 in between. 1 coil 16. Wound in a groove concentrically dug in. N12 coil 17. Takashi 3 coil 18. Pigeon 4 coils 19. The square rings 20° and 21 form two transformers. i.e. -1 coil 16 and rod 30
A rotor 12 and a stator 14 made of magnetic material are coupled together via a gap 15 using a magnetic core to form a transformer. Similarly, the N2 coil 17 and the 14th coil 19 form a transformer. The rotary head and the amplifier and drive circuit of the signal processing circuit are coupled through this rotary transformer, and signals are exchanged. @Figure 1 (bl is a simple circuit of the rotary transformer in Figure 1 (a), and the corresponding windings are given the same numbers. The terminals 22 and 23 of the rotary transformer are connected to the first rotating head, and the terminals 24 and 25 on the stator side are connected to the signal processing circuit. is connected to the second rotary head, and the terminals 28 and 29 on the stator side are connected to the signal processing circuit.There are disadvantages such as high cost due to the requirement of precision machining.In other words, in the rotary transformer, In order to reduce insertion loss, the coupling coefficient must be made thicker, but the coupling of the transformer depends on how small the gap 15 between the magnetic cores between the rotor 12 and the stator 14 is made.
For example, the current floor (5
The disadvantage is that the gap must be extremely small, from 0 μm to 100 μm, and the machining accuracy must be extremely high.

Another drawback was that it was unable to transmit direct current components or low frequency components due to transformer coupling.

[Purpose of the invention]

The present invention has been devised in consideration of these circumstances, and its purpose is to eliminate the need for precision structural machining in a single-rotation head helical scan type magnetic recording/reproducing device. That is, the object of the present invention is to provide a coupling method between a rotary head and a signal processing circuit that can transmit a DC component even if the machining accuracy is low.

[Summary of the invention]

The present invention includes a light-receiving or light-emitting element attached to the rotary head disk on the rotation axis of the rotary head disk, a fixed light-receiving or light-emitting element placed on an extension of the rotation axis, and a light-receiving or light-emitting element attached to the rotation axis of the rotary head disk. One light-receiving or light-emitting element is fixed at a position where signals can be transmitted by optical coupling with the attached light-receiving or light-emitting element, and the rotating head disk is fixed on the rotating shaft and can transmit signals by optical coupling with the nine light-receiving or light-emitting elements. The attached light-receiving or light-emitting element performs optical transmission between the element on the opposing rotary head disk and the fixed element, thereby coupling the rotary head and the signal processing circuit.

〔Effect of the invention〕

As described above, the present invention combines rotary '\rad signal processing by optical transmission between two light-receiving or light-emitting elements on a rotating head disk and two fixed light-receiving or light-emitting elements. It has the advantage of being able to easily transmit signals without requiring high machining precision like a rotary transformer, and it also has the advantage of being able to transmit DC components as it does not have inductance like a rotary transformer.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to one drawing.

FIG. 2 is a schematic cross-sectional view of a coupling method of a rotary head and a signal processing circuit constructed by applying the present invention, in which 31 is a rotary head disk, 32 is a stator, 33 and 34 are light emitting elements, and 35
．． 36 is a light receiving element. When recording by transmitting a signal from a signal processing circuit to the rotary head attached to the rotary head disk 31, the recording signal drives a light emitting element 34 such as an LED, and the light from one light emitting element 34 is transmitted to a light receiving element 35. Recording is performed by passing a signal current through the rotary head in response to a signal from the light receiving element 35, which is received and extracted by the light receiving element 35. On the other hand, during reproduction, the light emitting element 33 is driven by a reproduction signal from the rotating head, and the signal is received by the light receiving element 36 facing the light emitting element 33 and taken out. At this time, the light emitting element 33 rotates around the rotation axis of the rotary head disk, but if the central axis of the light emitting element 33 passes through the light receiving element 36, the angle of incidence of light on the light receiving element 36 changes due to rotation, but sufficient reception is possible. It's an angle. Similarly, the angle of incidence on the light-receiving element 35 changes with rotation, but if the light-emitting elements 33, 34 are placed very close to the rotation axis, the angle of incidence will be sufficiently small to cause no problem in reception. The power consumption of the light emitting element 33 and the light receiving element 35 mounted on the rotating head disk can be easily supplied by a slip ring attached to the lower part of the motor shaft 37 or a combination of the light emitting element and a solar cell. In this way, the coupling method using the optical transmitter/receiver circuit that couples the rotating head and the signal processing circuit eliminates the problem of machining accuracy between the rotor and stator like in a rotary transformer (in addition, it is possible to transmit up to DC components). Become.

As explained above, the method of coupling the rotary head and the signal processing circuit according to the present invention not only has the advantage of being extremely low in cost because it does not require structural precision machining, but also has the advantage of being able to transmit DC components, so it is possible to transmit signals. There are also advantages such as easier processing.

Note that the present invention is not limited to the above embodiments. For example, in the above embodiment, the light-receiving element is placed on the circuit axis, but it is of course possible to place the light-emitting element on the rotation axis and use the opposite position as the light-receiving element. It consists in arranging. In short, the present invention can be implemented with various modifications without departing from the gist thereof.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of a rotary transformer and its simple equivalent circuit, and FIG. 2 is a schematic sectional view of a coupling circuit of a rotary head disk and a signal processing circuit to which the present invention is applied. 12...Rotor, 14...Stator, 16.17,1
8゜19... Coil, 31... Rotating head disk, 33゜34... Light emitting element, 35.36... Light receiving element. Representative Patent Attorney Kensuke Chika (and 1 other person) Figure 1 1) Figure 2

Claims (1)

[Claims] In a rotating head/helical scan type magnetic recording/reproducing device, a light receiving or emitting element disposed on a rotating head disk on a rotating shaft of a single rotating head disk, and a light receiving or emitting element fixedly arranged on an extension of the rotating shaft. A light-emitting element, and a light-emitting or light-receiving element disposed on the rotating RAD disk 2 and at a fixed point, respectively, facing the light-receiving or light-emitting element disposed at the two locations, the light-receiving or light-emitting element on the rotating head disk and 1. A magnetic recording and reproducing device characterized in that a signal is coupled between a rotary head and a signal processing circuit by transmitting light between nine fixed light-receiving or light-emitting elements.