JPH06131606A - Rotary head device - Google Patents

Abstract

PURPOSE:To miniaturize an entire device by providing light emitting elements and light receiving element respectively on rotary drum and fixed drum sides and making respective light receiving elements photoelectric conversion elements formed annularly around the center of the rotation of the rotary drum. CONSTITUTION:An electric signal is inputted to the light emitting element 18 of the fixed drum 11 and converted into an optical signal, and the optical signal is emitted. The optical signal is incident on the light receiving element 17 on the rotary drum 14 and converted photoelectrically, and after it is detected and amplified, it is outputted to a magnetic head 15, and writing is performed on a magnetic tape. The signal detected by the magnetic head 15 is emitted from the light emitting element 16 as the optical signal at a reproducing time. The optical signal is incident on the annular light receiving element 19 of the fixed side, and is converted photoelectrically by the light receiving element 19 and outputted as the electric signal. At this time, the device is constituted so that a phase generation function is carried by a fact that a part of the annular shape of the light receiving element 19 is notched by a (360 deg.-alpha) angle. Thus, highly precise head tracing is realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary head device in a VTR, DAT or the like, and more particularly to a signal transmission structure between a fixed drum and a rotary drum.

[0002]

2. Description of the Related Art Conventionally, in a rotary head device in a VTR, DAT, etc., a rotary transformer is incorporated in a cylinder of a rotary head drum in order to efficiently extract a reproduction signal from a rotating head.
The reproduction signal from the head is taken out to the fixed drum side via this rotary transformer.

However, in such a rotary transformer, it is necessary to manufacture the core of the rotary transformer with high precision, and high precision assembly is also required in assembling, so that the cost is relatively high. Moreover, there is a problem that the assembly work is troublesome and the high frequency characteristics are not so good.

Therefore, as shown in FIG. 5, there has been proposed a rotary head device utilizing optical coupling for signal transmission between the fixed side drum and the rotating side drum. In FIG. 5, the rotary head device 1 includes a fixed drum 2, a bearing 3 incorporated in the fixed drum 2, and a rotating shaft 4 rotatably supported by the bearing 3 around the center line of the fixed drum 2. And a yoke 5 attached to the rotary shaft 4.
And a rotary drum 6 integrally attached to the rotary shaft 4 in the same manner.

The yoke 5 has a coil 5a on its outer peripheral edge.
By including the above, a motor is configured, and the rotary drum 6 can be driven to rotate around the rotary shaft 4 by the motor. The rotary drum 6 also includes a pair of magnetic heads 6b and 6c mounted via a support member 6a.

Further, in the rotary head device 1, the light emitting element 7a and the light receiving element 7b are arranged on the rotary drum 6. A light emitting element 8a and a light receiving element 8b are fixedly arranged above the rotary drum 6 so as to face the light emitting element 7a and the light receiving element 7b arranged on the rotary drum 6. Here, the light emitting element 7a and the light receiving element 7b are arranged with respect to the rotation center of the rotary drum 6.
The light receiving elements 7b are arranged on the same circumference and are formed in an annular shape. Further, the light emitting element 8a and the light receiving element 8b
Also, similarly, the light receiving element 7b is arranged on the same circumference with respect to the rotation center of the rotary drum 6, and the light receiving element 7b is formed in an annular shape.

Each of the light receiving elements 7b and 8b shown in FIG.
As shown in FIG. That is, the light receiving element 7b will be described. The light receiving element 7b is composed of a large number of optical fibers 9, and the light receiving end surface of the optical fiber 9 is positioned in a plane perpendicular to the rotation axis of the rotary drum 6. It has become. Further, the light receiving end surface of the optical fiber 9 is annularly arranged so as to form a semicircular arc centered on the rotation axis of the rotary drum 6. The end face on the opposite side of the optical fiber 9 is wound and bundled so as to face the photodetector 9a. As a result, the photodetector 9a is adapted to generate an electric signal when the light is guided by the optical fiber 9 and made incident when the optical fiber 9 receives the light.

According to the rotary head device 1 having such a configuration, during reproduction, the signals detected by the magnetic heads 6b and 6c are emitted from the light emitting element 7a as an optical signal. This optical signal enters the fixed-side light receiving element 8b and enters the photodetector via the optical fiber. Here, the optical signal can be converted into an electric signal again by the photodetector and output to a control circuit or the like (not shown). Further, at the time of recording, an electric signal from a control circuit (not shown) or the like is input to the fixed side light emitting element 8a. As a result, the light emitting element 8a converts the electric signal into an optical signal and emits the optical signal. This optical signal is incident on the light receiving element 7b provided on the rotary drum 6, and is incident on the photodetector 9a via the optical fiber 9. Then, this optical signal is converted into an electric signal again by the photodetector 9a, output to the magnetic heads 6b and 6c, and writing on the magnetic tape can be performed.

[0009]

However, in such a rotary head device, since the optical fiber 9 is used as the light receiving elements 7b and 8b, an annular light receiving portion is formed. Although the high frequency characteristic can be improved, there is a problem that the light receiving elements 7b and 8b become relatively large and the rotary head device 1 as a whole becomes large. Further, the optical fiber 9 is relatively expensive, and there is a problem that the overall cost becomes high. Furthermore, since each of the light receiving elements 7b and 8b can transmit only one signal as a whole, it is impossible to transmit the phase information of the head and the like.

In view of the above points, it is an object of the present invention to provide a rotary head device which can be constructed in a small size and at low cost and can transmit phase information and the like.

[0011]

According to the present invention, the above object includes a fixed drum and a rotary drum rotatably supported with respect to the fixed drum. In the rotary head device, which is configured to input and output signals from the fixed drum side to the head,
The rotating drum is provided with at least a pair of the rotating side light emitting element and the rotating side light receiving element, and the fixed drum side faces the light emitting element and the light receiving element, respectively.
A fixed side light receiving element and a fixed side light emitting element are provided, and the rotating side light receiving element and the fixed side light receiving element are photoelectric conversion elements formed in an annular shape around the rotation center of the rotating drum, respectively. Which is achieved by a rotary head device.

Preferably, the rotating side light emitting element and the fixed side light receiving element, the fixed side light emitting element and the rotating side light receiving element,
Multiple pairs are provided for each.

Preferably, the rotating side light receiving element and the fixed side light receiving element are photoelectric conversion type position detecting elements each formed in an annular shape around the rotation center of the rotating drum.

Further preferably, the light emitting element and the light receiving element on the rotary drum are mounted on one substrate, and the light emitting element and the light receiving element on the fixed side are mounted on another substrate. There is.

[0015]

According to the above construction, at the time of reproduction, the signal from the magnetic head is converted into an optical signal by the rotating side light emitting element and is incident on the opposed annular fixed side light receiving element, and the electric signal is again generated. The signal is converted into a signal, and at the time of recording, an electric signal from the outside is converted into an optical signal by the fixed side light emitting element,
The light is incident on the opposed annular fixed-side light receiving element, is converted into an electric signal again, and is input to the magnetic head.
Writing can be performed on the magnetic tape.

When a plurality of pairs of the rotating side light emitting element and the fixed side light receiving element, and the fixed side light emitting element and the rotating side light receiving element are provided, a signal of one channel can be transmitted by each pair.

Further, when the rotating side light receiving element and the fixed side light receiving element are photoelectric conversion type position detecting elements formed in an annular shape around the rotation center of the rotating drum, respectively,
The rotational position of the rotary head can be detected.

The light emitting element and the light receiving element on the rotating drum are
When mounted on one substrate, the fixed side light emitting element and the light receiving element are mounted on another one substrate, the structure is simple, and the light emitting element and the light receiving element, respectively, It can be formed at the same time.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described in detail with reference to FIGS. The examples described below are preferred specific examples of the present invention, and therefore, various technically preferable limitations are given, but the scope of the present invention particularly limits the present invention in the following description. Unless otherwise stated, the present invention is not limited to these modes.

FIG. 1 shows a first embodiment of the rotary head device according to the present invention. In FIG. 1, a rotary head device 10 includes a fixed drum 11, a bearing 12 incorporated in the fixed drum 11, and a rotary shaft rotatably supported by the bearing 12 around a center line of the fixed drum 11. 13 and a rotary drum 14 attached to the rotary shaft 13. Here, this rotating drum 1
The magnetic head 4 has a pair of magnetic heads 15 near its outer peripheral edge.

Further, the lower surface of the rotary drum 14 is shown in FIG.
As shown in, a light emitting element 16 and a light receiving element 17 are arranged. Further, as shown in FIG. 3, a light emitting element 18 and a light receiving element 19 are provided on the inner bottom surface of the fixed drum 11 so as to face the light emitting element 16 and the light receiving element 17 arranged on the rotating drum 14. Is fixedly placed.

Here, the light emitting element 16 and the light receiving element 17
2 are arranged on the same circumference with respect to the center of rotation of the rotary drum 14, and the light receiving element 17 has an annular shape only in the section of the angle α (α <360 degrees). Is formed in.

The light emitting element 18 and the light receiving element 19 are also
Similarly, as shown in FIG. 3, the light receiving element 19 is arranged on the same circumference with respect to the rotation center of the rotary drum 14, and the light receiving element 19 is circular only in the section of the angle α (α <360 degrees). It is formed in a ring shape.

This embodiment is configured as described above, and an electric signal from a control circuit (not shown) or the like is input to the light emitting element 18 of the fixed drum 11 during recording. As a result, the light emitting element 18 converts the electric signal into an optical signal and emits the optical signal. This optical signal enters the light receiving element 17 provided on the rotary drum 14, is photoelectrically converted, and is detected and amplified by a circuit provided on the rotary drum 14 (not shown), and then output to the magnetic head 15. To be done. This causes the magnetic head 15 to write on the magnetic tape.

During reproduction, the signal detected by the magnetic head 15 is emitted from the light emitting element 16 as an optical signal. This optical signal is incident on the fixed-side annular light receiving element 19, is photoelectrically converted by this light receiving element 19, and can be output as an electric signal to a control circuit (not shown) or the like. At this time, since a part of the annular shape of the light receiving element 19 is cut out by an angle (360 degrees-α), P
A G (phase generation) function can be provided.

FIG. 4 shows a second embodiment of the rotary head device according to the present invention. In FIG. 4, the rotary head device 20 includes a first printed circuit board 21 to be mounted on the rotary drum and a second printed circuit board 22 to be mounted on the fixed drum.

On the lower surface of the first printed board 21, there are two pairs of light emitting elements and light receiving elements, that is, the light emitting elements 23,
24 and light receiving elements 25 and 26. Here, the light emitting element 23 and the light receiving element 25 are arranged on the same circumference, and the light emitting element 24 and the light receiving element 26 are on the same circumference inside the light emitting element 23 and the light receiving element 25. It is arranged. Further, the light receiving elements 25 and 26 are photoelectric conversion elements formed in an annular shape.

On the upper surface of the second printed circuit board 22, two pairs of light emitting elements and light receiving elements, that is, the light emitting elements 2 are provided.
7, 28 and light receiving elements 29, 30. Here, the light emitting element 27 and the light receiving element 29 are arranged on the same circumference so as to face the light emitting element 23 and the light receiving element 25 of the first printed board 21, and the light emitting element 28 and the light receiving element 28 are arranged. The element 30 corresponds to the first printed circuit board 21.
Are arranged on the same circumference inside the light emitting element 27 and the light receiving element 29 so as to face the light emitting element 24 and the light receiving element 26. Further, the light receiving elements 29 and 30 are
It is a photoelectric conversion element formed in an annular shape.

The rotary head device 20 constructed in this way
According to this, for example, the light emitting element 23 and the light receiving element 29, and the light emitting element 27 and the light receiving element 25 are combined to perform input and output of signals to and from the magnetic head, and the light emitting element 2
4 and the light receiving element 30, the light emitting element 28 and the light receiving element 26.
It is possible to input and output signals to and from the magnetic head as a set. Therefore, in this structure, two-channel signal input / output can be performed.

In this case, since the light emitting element and the light receiving element are formed on the single printed circuit board on the rotating side and the fixed side, respectively, the simple structure can be produced at low cost, and The assembly can be easily performed.

In the above-mentioned embodiment, the light receiving elements 17, 19 or 25, 26, 29, 30 are all photoelectric conversion elements. However, when the photoelectric conversion type position detecting element is used, The position at which is incident can be detected at the same time. Therefore, this allows the rotational angle position of the rotary head to be detected and the phase information of the magnetic head of the rotary head to be obtained. Thus, highly accurate head trace can be realized based on the phase information of the magnetic head.

[0032]

As described above, according to the present invention, since the annular photoelectric conversion element is used as the light receiving element, the light receiving element can be made small and thin. The entire rotary head device can be downsized. When a plurality of pairs of the rotating side light emitting element and the fixed side light receiving element, and the fixed side light emitting element and the rotating side light receiving element are provided, signals of a plurality of channels can be transmitted at the same time. Further, when the rotating side light receiving element and the fixed side light receiving element are photoelectric conversion type position detecting elements formed in an annular shape around the rotation center of the rotating drum, the rotating position of the rotating drum is detected. You will get it. Therefore, the phase information of the magnetic head of the rotating drum can be obtained with high accuracy, and the head trace with high accuracy can be performed based on this phase information. Furthermore, when the light emitting element and the light receiving element on the rotating drum are mounted on one substrate, and the light emitting element and the light receiving element on the fixed side are mounted on another one substrate, However, the light emitting element and the light receiving element can be formed at the same time, and the cost can be significantly reduced especially in the case of multiple channels.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a first embodiment of a rotary head device according to the present invention.

FIG. 2 is a bottom view of a rotary drum in the rotary head device of FIG.

3 is a plan view of a fixed drum in the rotary head device of FIG. 1. FIG.

FIG. 4 is a schematic perspective view showing a relationship between a light emitting element and a light receiving element in the second embodiment of the rotary head device according to the present invention.

FIG. 5 is a schematic cross-sectional view showing an example of a conventional rotary head device.

6 is a perspective view of a light receiving element in the rotary head device of FIG.

[Explanation of symbols]

 10 rotary head device 11 fixed drum 12 bearing 13 rotary shaft 14 rotary drum 15 magnetic head 16 light emitting element 17 light receiving element 18 light emitting element 19 light receiving element 20 rotary head device 21 printed board 22 printed board 23 light emitting element 24 light emitting element 25 light receiving element 26 Light receiving element 27 Light emitting element 28 Light emitting element 29 Light receiving element 30 Light receiving element

Claims (4)

[Claims] 1. A fixed drum and a rotary drum rotatably supported with respect to the fixed drum, wherein signals are input and output from the fixed drum side to a magnetic head mounted on the rotary drum. In the rotary head device, the rotary drum is provided with at least a pair of the rotary side light emitting element and the rotary side light receiving element, and the fixed drum side faces the light emitting element and the light receiving element, respectively.
A fixed side light receiving element and a fixed side light emitting element are provided, and the rotating side light receiving element and the fixed side light receiving element are photoelectric conversion elements formed in an annular shape around the rotation center of the rotating drum, respectively. The rotary head device. 2. The rotary head device according to claim 1, wherein a plurality of pairs of the rotating side light emitting element and the fixed side light receiving element, and a plurality of fixed side light emitting element and the rotating side light receiving element are provided. . 3. The photoelectric conversion type position detecting element, wherein each of the rotating side light receiving element and the fixed side light receiving element is a photoelectric conversion type position detecting element formed in an annular shape around a rotation center of a rotating drum. The rotary head device according to 2. 4. The light emitting element and the light receiving element on the rotary drum are mounted on one board, and the light emitting element and the light receiving element on the fixed side are mounted on another board. The rotary head device according to any one of claims 1 to 3, which is characterized.