JPH0551191B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a rotating body signal transmission device that is used in, for example, video tape recorders, rotating machines, robot arms, etc., and transmits signals between a rotating part and a fixed part. It is related to.

[Prior Art] FIG. 7 is a sectional view showing a conventional rotating body signal transmission device disclosed in, for example, Japanese Patent Laid-Open No. 48-37081, and FIG. 8 is a perspective view thereof. Seventh of these
In Fig. 8, 1 is the rotating drum of the VTR;
2 is also a fixed drum, 3 and 4 are magnetic heads (not shown in FIG. 7), 5 is an amplifier mounted on the rotating drum 1, 6 is a rotating shaft, 7 is a light emitting element such as a light emitting diode, 8 is a light receiving element such as a photodiode or a phototransistor; 9 is a brush; 10
is the support.

In the conventional rotating body signal transmission device having such a configuration, when a recording operation is first performed, a video signal is inputted via the brush 9 and recorded on a magnetic tape. On the other hand, during the retransmission operation, power is supplied from the brush 9 to the amplifier 5, and a video signal, etc. is input to the amplifier 5 via the magnetic heads 3 and 4, and is amplified by the amplifier 5. A video signal and the like are given to the light emitting element 7. This light emitting element 7 can modulate its output light with a high frequency of several MHz, and in this case, its output is modulated with a video signal.

Since the light receiving element 8 is arranged facing the light emitting element 7 as shown in FIGS. 7 and 8, light from the light emitting element 8 is transmitted to the light receiving element 8.

[Problems to be Solved by the Invention] Since the conventional rotating body signal transmission device is configured as described above, the positions of the light emitting element 7 and the light receiving element 8 facing thereto are coaxial with the rotating shaft 6. There is a problem in that high precision is required for the positioning, which increases cost.Also, even if both end faces of the rotating shaft 6 are used as the installation location for the light emitting element, it is difficult to install multiple channels of three or more channels. Communication is difficult. Therefore, there was a problem in that it could not be compatible with VTRs that recorded and played back multiple channels on tape, such as 8mm video with PCM recording, digital VTRs, and high-definition VTRs.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to obtain a rotating body signal transmission device that can optically transmit multi-channel signals.

[Means for Solving the Problems] The rotating body signal transmission device according to the present invention includes a light emitting means provided in either the rotating part or the fixed part, and a light emitting means provided in the other of the rotating part or the fixed part,
The light receiving means is provided at a position facing the light emitting means and receives the light beam from the light emitting means, and the light receiving means is provided with a means for extracting a signal contained in the light beam from the light beam received by the light receiving means. It has a tapered shape with a reflecting mirror, and the luminous flux emitted from the light emitting means is condensed on its inner surface.

[Function] Since the tapered reflecting mirror of the present invention condenses the signal light from the light emitting element that enters the opening, the light emitting axis and the light emitting axis can be aligned with high precision in the relationship between the rotating part and the fixed part. Even if they do not match, it is possible to easily transmit signal light,
Even when a plurality of light emitting elements generate light of different wavelengths, the light from the plurality of light emitting elements is collected by the tapered reflecting mirror and introduced into the light receiving element.

[Examples] Examples of the present invention will be described below with reference to the drawings.
FIG. 1 is a sectional view showing a rotating body signal transmission device according to an embodiment of the present invention. In the figure, the same reference numerals as in FIG. 7 are the same, and the explanation thereof will be omitted here. In the figure, numerals 11 and 12 are light emitting elements having different wavelengths, and are mounted on a printed circuit board 13. In addition, these light emitting elements 1
1 and 12 are modulated by the outputs of the magnetic heads 3 and 4, or by individual signals processed from these signals. 13 is a printed circuit board that rotates together with the rotating drum 1. 14 is a tapered reflecting mirror (reflecting mirror) provided on the fixed side. This tapered reflecting mirror is a conical reflecting mirror, and its inner surface is configured to easily reflect light. FIG. 2 shows an enlarged view of the main parts mentioned above. In the upward direction in the figure, most of the energy is transferred to the tapered reflector 1.
4 and is focused on the throat section 24.
A light guide 15 is connected to the throat portion 24, and the light collected by the tapered reflecting mirror 14 is guided through the light guide 15. A rod lens 16 is bonded to the end surface 23 of the light guide 15. This rod lens 16 is. The refractive index near the central axis is higher than that at the outer periphery, and light incident from the end face 23 is focused by this rod lens 16 and output as a light beam 17. 18 is a prism,
Light beam 1 depending on the wavelength contained in light beam 17
It is separated into 9 and 20. 21 and 22 are light receiving elements, and the light emitting elements 11 and 12 are connected from their respective output terminals.
This is to obtain a signal corresponding to the signal added to the signal.

The operation of the rotating body signal transmission device of the present invention configured as described above will be explained below. Light emitting elements 11 and 12 provided on the printed circuit board 12 of the rotating drum 1 that receives signals from the magnetic heads 3 and 4
are modulated into individual signals by This modulated signal is emitted as an optical signal from the light emitting elements 11 and 12, and the tapered reflecting mirror 14 is fixed.
The light energy is captured by the throat section 24.
The light is focused on. The optical signal focused on the throat portion 24 is outputted as a light beam 17 by a light guide 15 and a rod lens 16. Since the output light beam 17 has two wavelengths, it is separated by the prism 18 into light beams 19 and 20 according to these wavelengths. These light beams 19 and 20 enter light receiving elements 21 and 22, respectively, and the light receiving elements 2
1 and 22, a signal corresponding to the signal input to the above-mentioned light emitting elements 11 and 12 is obtained.

In this way, two channels of signals are transmitted from the rotating light emitting elements 11 and 12 to the fixed light receiving element 2.
1 and 22. That is, the light emitting element 11,
12 and the tapered reflecting mirror 14 are arranged as described above, so that even if the rotating drum 1 rotates, signal transmission can be performed without any problem.

Note that the above embodiment was constructed using a conical tapered reflecting mirror 14 as shown in FIG.
As shown in FIG. 3, the shape may be a wrap shape. Alternatively, the tapered reflector 14 and the rod lens 16 may be directly coupled without using the light guide 15. Furthermore, instead of the rod lens 16 and prism 18, a concave mirror having a light diffraction grating on its surface as shown in FIG. 4 may be used to separate the light into wavelengths and supply them to the respective light receiving elements 21 and 22. Further, as shown in FIG. 5, reflecting mirrors 25 and 26 may be used to reflect the light of the respective wavelengths of the light emitting elements 11 and 12.

Further, in the above embodiment, the light emitting elements 11 and 12 were provided on the rotating side and the tapered reflector 14 was fixedly arranged, but recording signals are sent from the magnetic heads 3 and 4 to the magnetic tape (not shown). In this case, as shown in FIG. 6, the light emitting elements 11 and 12 are provided on the fixed printed circuit board 13, and the tapered reflector 14, rod lens 16, prism 18, light receiving element 21,
22 may be arranged on the rotating drum 1, and the same effect as in the above embodiment can be achieved.

In the above embodiment, the case of a VTR was described as an example, but the application is not limited to this, and it can also be used to transmit signals from a rotating part to a fixed part, such as measuring the temperature of a rotor of a rotating machine, or to transmit signals from a joint part of a robot. It may also be used for this purpose, and the same effect as in the above embodiment can be obtained.

Furthermore, the number of light emitting elements or light receiving elements is not limited to two, but may be one or three or more.

[Effects of the Invention] As described above, according to the present invention, the light emitting means provided on either the rotating part or the fixed part;
A light receiving means, which is provided at a position facing the light emitting means on the other of the rotating part or the fixed part, and receives the light beam from the light emitting means, and a signal contained in the light beam received by the light receiving means. The light receiving means has a tapered shape with a reflecting mirror on the inner surface, and the light receiving means is configured to condense the emitted light beam from the light emitting means on the inner surface, so that the emitted light beam is efficiently transmitted. In addition, there is a large degree of freedom in the arrangement of the light emitting element and the tapered reflector, and the mounting accuracy tolerance is wider than that of conventional devices, so it can be constructed at low cost, and by arranging a large number of light receiving elements, it is possible to create multiple channels. It has the effect of being easy.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a rotating body signal transmission device according to an embodiment of the present invention, FIG. 2 is an enlarged detailed view of main parts such as a light emitting element and a tapered reflector shown in FIG. 1, and FIG. FIG. 4 is a diagram showing a diffraction grating in another embodiment of the invention; FIG. 5 is a diagram showing the wavelength of a light beam in another embodiment of the invention. FIG. 6 is a sectional view showing a configuration for transmitting signals from the stationary side to the rotating side in another embodiment of the present invention, and FIG. 7 shows a conventional rotating body signal transmission device. The sectional view and FIG. 8 are its perspective views. In the figure, 1 is a rotating drum, 3 and 4 are magnetic heads, 6 is a rotating shaft, 11 and 12 are light emitting elements, and 13
14 is a printed circuit board, 14 is a reflecting mirror, 15 is a light guide, 16 is a rod lens, 17, 19, and 20 are light beams, 18 is a prism, and 21 and 22 are light receiving elements. Note that the same reference numerals in each figure indicate the same or equivalent parts.

Claims (1)

[Scope of Claims] 1. In a device that transmits a signal from either a rotating part connected to a predetermined support shaft and rotating around this support shaft, or a fixed part as an optical signal to the other, said rotating part or a light-emitting means provided on either one of the fixed parts; a light-receiving means provided on the other of the rotating part or the fixed part at a position facing the light-emitting means and receiving the luminous flux from the light-emitting means; The light receiving means includes a means for extracting a signal included in the light flux received by the light receiving means, and the light receiving means has a tapered shape with a reflecting mirror on the inner surface, and the light receiving means has a tapered shape with a reflecting mirror on the inner surface. A rotating body signal transmission device characterized by concentrating light. 2. The rotating body signal transmission device according to claim 1, wherein the light emitting means has a substantially conical shape. 3. The light emitting means is composed of a plurality of light emitting elements that each emit light beams of different wavelengths, and the light beam collected by the light receiving means is split into different light beams by the next-stage spectroscopic means. A rotating body signal transmission device according to claim 1 or 2.