JP2007243357A - Transmitter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmitter suitable for a motor-driven monitoring camera for executing optical transmission in two asymmetrical directions without losing optical power of an optical transmission system for transmitting/receiving signal light with a large amount of information. <P>SOLUTION: The transmitter is configured such that when a fixed part side unit contained in a fixed part 3 fixed to a prescribed member, and a rotary part side unit contained in a rotary part 2 rotatably coupled to the fixed part via a coupling part including a throughhole 30 penetrated in a direction of a rotary axis, transmit an optical signal through the throughhole of the coupling part in two directions, a first light emitting element 6 of the fixed part and a second light receiving element 10 of the fixed part 3 are used to transmit the optical signal from the rotary part to the fixed part, and a second light emitting element 18 and a second optical member 8 of the fixed part and a first optical member 7 and a first light emitting element 19 of the rotary part, are used to transmit the optical signal from the fixed part to the rotary part. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a rotating part side housed in a rotating part that is rotatably coupled to a fixing part via a fixing part side device housed in the fixing part and a coupling part having a through hole penetrating in the rotation axis direction. The present invention relates to a transmission device that transmits optical signals in both directions.

  2. Description of the Related Art Conventionally, in a device having a rotating unit that rotates in a relatively large angle range, for example, an electric surveillance camera, a wired connection is partly configured as a structure that transmits a signal to a fixed unit while the rotating unit housing the camera rotates. It was adopted. However, since it is not possible to adopt a wired connection for a structure that enables the camera to rotate endlessly in the same direction for important surveillance applications, an electrical signal is transmitted by sliding contact between a brush called a slip ring and a contact. It was.

  FIG. 5 is a schematic configuration diagram of a conventional electric surveillance camera that transmits an electrical signal using a slip ring. In FIG. 5, the electric surveillance camera 101 includes a rotating unit 102, a fixed unit 103, and an external controller 104, and among these, the rotating unit 102 is rotatably coupled to the fixed unit 103 via a coupling unit 105. . The rotating unit 102 accommodates a camera 106 and a tilt driving unit 107 that tilts the camera 106 in the vertical direction. The fixing unit 103 is fixed to a ceiling, a desk, or the like, and includes a power source circuit 108, a control circuit 109, a pan driving unit 110 that rotates the rotating unit 102 in the horizontal direction, an image processing circuit 111, and the like. A network circuit 112 is accommodated, and a video output connector 113 is further provided. The coupling unit 105 includes a slip ring, which will be described later, through which the power supply circuit 108 supplies driving power to the tilt driving unit 107 from the fixed unit 103 to the rotating unit 102, and the control circuit 109 performs tilt driving. A control signal is added to the unit 107, and the camera 106 transmits a video signal to the image processing circuit 111 from the rotating unit 102 side to the fixed unit 103 side.

  In the electric surveillance camera 101 configured as described above, the control circuit 109 applies a control signal to the pan driving unit 110 and the tilt driving unit 107 in response to a command from the external controller 104, whereby the camera 106 has a desired pan angle, The tilt angle is adjusted. The video signal of the camera 106 is guided to a rotating unit side substrate (not shown) via a flexible substrate or a wire cable, and from the rotating unit side substrate via a slip ring of the coupling unit 105, the fixed unit side substrate. (Not shown) and supplied to the image processing circuit 111. The video signal image-processed by the image processing circuit 111 is transmitted by the network circuit 112 to a network (not shown) connected to the video output connector 113.

  FIG. 6 is a cross-sectional view showing a detailed configuration of the coupling portion 105 including a slip ring. The coupling portion 105 is mounted on the inner side of the fixed cylinder portion 121 via a pair of bearings 123 so that the rotating cylinder 122 can be rotated, and an annular contact 124 provided on the outer peripheral portion of the rotating cylinder 122. The brush 125 provided on the inner periphery of the fixed cylinder 121 is configured to be in sliding contact.

  In FIG. 6, a slip ring is formed by the contact 124 and the brush 125, and this slip ring is used for supplying driving power to the tilt driving unit 107 and transmitting a control signal and transmitting a video signal of the camera 106. Further, it is also used for transmission of zero point detection information from the rotating unit 102 to the control circuit 109.

  However, since the slip ring involves mechanical contact, signal transmission quality at the contact portion becomes a problem. That is, when a control signal is transmitted, a failure is likely to occur. When a high-definition camera is used as the camera 106, the signal signal at the contact portion is unacceptable due to the wide frequency range of the video signal. . Therefore, there has been a demand for a connection means with good transmission quality and high reliability in place of the slip ring.

  As a conventional technique for solving such a problem, an apparatus for transmitting an optical signal by securing a transmission path for transmitting a video signal of a camera to a rotating shaft instead of a slip ring is disclosed (for example, the following) Patent Document 1). This device is equipped with a light emitting element at one end so that the optical axis coincides with the rotational axis of the rotating body forming the slip ring, and the light receiving element is attached to the fixed part so that the optical axis coincides with the light emitting element. The optical transmission system is configured by arranging. With this configuration, power and control signals can be transmitted via a slip ring, and a video signal with a wide frequency range of a high-definition camera can be transmitted using an optical transmission system.

  Since this apparatus transmits a video signal having a wide frequency range using an optical transmission system, it can ensure good transmission quality. However, since power and control signals are transmitted through the slip ring, the problem of failure due to brush contact still existed.

As a solution to this problem, an apparatus that bi-directionally transmits signals between a rotating unit and a fixed unit is disclosed (for example, see Patent Document 2 below). In this device, the fixed portion side light emitting element and the rotating portion side light receiving element are arranged on the axis of the rotating shaft, and the fixed portion side light receiving element and the rotating portion side light emitting element are arranged and fixed at a position off the axis. By arranging the fixed part side half mirror and the rotating part side half mirror on the optical axis between the part side light emitting element and the rotating part side light receiving element, the signal light emitted from the fixed part side light receiving element is rotated. An optical transmission system that receives light by the side light receiving element and an optical transmission system that reflects the signal light emitted from the rotating part side light emitting element by the rotating part side half mirror and the fixed part side half mirror and receives the light by the fixed part side light receiving element. And bi-directional optical transmission.
JP 2001-183738 A (paragraph 0043, FIG. 2) JP 2002-271270 A (paragraph 0032, FIG. 12)

  In the electric surveillance camera using the high-definition camera, the information amount of the video signal of the camera transmitted from the rotating unit to the fixed unit is overwhelmingly larger than the information amount transmitted from the fixed unit to the rotating unit. Therefore, in the above-described apparatus for performing bidirectional optical transmission, the video signal of the camera is transmitted using an optical transmission system composed of a light emitting element and a light receiving element arranged on the axis of the rotation axis, and the axis of the rotation axis If a control signal or the like is transmitted using an optical transmission system in which a pair of half mirrors are arranged on a line, an asymmetric optical transmission device commensurate with the amount of information can be obtained. However, since the pair of half mirrors arranged on the axis reflects the signal light that transmits the video signal of the camera at a predetermined ratio, the optical power is lost by that amount, and the video signal of the high-definition camera is lost. There was a problem that transmission efficiency was lowered.

  The present invention has been made to solve the above-mentioned problems of the conventional apparatus, and is an electric motor that performs asymmetric bidirectional optical transmission without impairing the optical power of an optical transmission system that transmits and receives signal light with a large amount of information. An object of the present invention is to provide a transmission apparatus suitable for a surveillance camera.

In order to achieve the above-described object, the present invention is configured such that the fixing is performed via a fixing portion side device housed in a fixing portion fixed to a predetermined member and a coupling portion having a through hole penetrating in the rotation axis direction. A rotating part-side device housed in a rotating part that is rotatably coupled to the part, and a first optical transmission line that extends around the shaft core part of the through hole and a first part that extends around the shaft core part. A transmission device that transmits an optical signal bidirectionally through two optical transmission lines,
The rotating unit side device is:
A first light emitting element that emits signal light to the first optical transmission line;
A first light receiving element mounted at a position deviated radially outward from the through hole;
A first optical member that causes the first light receiving element to receive a light by changing a path of the signal light traveling through the second optical transmission path;
The fixed part side device is:
A second light receiving element for receiving signal light traveling through the first optical transmission line;
A second light emitting element that is mounted at a position that is radially outward from the through hole and emits signal light radially inward;
And a second optical member that changes the path of the signal light emitted from the second light emitting element to travel to the second optical transmission path.

  According to the present invention, an optical signal is transmitted from the first light emitting element to the second light receiving element through the first optical transmission path extending to the shaft core portion of the through hole, while extending around the shaft core portion. Because the optical signal is transmitted from the second light emitting element to the first light receiving element via the second optical member and the first optical member provided in the second optical transmission line. The optical power of the first optical transmission path is not impaired by the second optical member and the first optical member, thereby providing a transmission device suitable for an electric surveillance camera that performs asymmetric bidirectional optical transmission. The

Hereinafter, the present invention will be described in detail based on preferred embodiments shown in the drawings.
<First Embodiment>
FIG. 1 is a schematic configuration diagram of a first embodiment of an electric surveillance camera housing a transmission apparatus according to the present invention. In FIG. 1, the electric surveillance camera 1 includes a rotating unit 2 and a fixed unit 3. The rotating portion 2 is coupled to the fixed portion 3 by a coupling portion (not shown) having a through hole 30 penetrating in the rotating shaft direction so as to be rotatable about the rotating shaft R in the arrow X direction or the Y direction. . A waveguide 9 using a large-diameter optical fiber is held by a holding member (not shown) so as to rotate integrally with the rotating portion 2 in the axial core portion of the coupling portion, that is, in the center portion of the through hole 30. Has been. The rotating unit 2 emits signal light to the camera 4, a parallel-serial conversion unit (abbreviated as P → S conversion unit in the drawing) 5 for parallel-serial conversion of the video signal, and the waveguide 9. A laser diode section 6 and a region off the center of the through hole 30, that is, the periphery of the waveguide 9 as an optical transmission path, and a rotating section side mirror 7 for changing the path of signal light traveling through the optical transmission path; The rotating unit side light receiving element 19 that receives the signal light from the rotating unit side mirror 7, the tilt motor 22 that drives the camera 4 in the vertical direction, the driving unit 23, and the tilt origin detection SW 24 are housed. . Among these, the laser diode portion 6 is mounted on the substrate together with the driver, and the rotating portion side mirror 7 has a hole through which the waveguide 9 passes.

  On the other hand, the fixed portion 3 is a fixed portion side mirror that uses a region off the center of the through-hole 30, that is, the periphery of the waveguide 9 as an optical transmission path, and changes the path so that the signal light travels in this optical transmission path 8, a fixed portion side light receiving element 10 that receives the signal light traveling through the waveguide 9, and an O / E conversion portion 11 that converts a signal corresponding to the light intensity of the fixed portion side light receiving element 10 into an electrical signal, A serial-parallel conversion unit (abbreviated as S → P conversion unit in the drawing) 12, a control circuit 13, a power supply circuit 14, a video output connector 15, and a control circuit 13 that perform serial-parallel conversion on the converted electrical signal. A parallel-serial conversion unit 16 for parallel-serial conversion of the control signal from the output signal, an E / O conversion unit 17 for converting the control signal into a signal corresponding to the luminous intensity, and an optical signal corresponding to the converted luminous intensity. To illuminate the fixed part side mirror 8 A laser diode unit 18, a pan motor 25 for driving the rotating unit 2 in the horizontal direction, and a driving unit 26, an image processing circuit 27, and a network circuit 28 is housed. Among these, the laser diode portion 18 is mounted on the substrate together with the driver, and the fixed portion side mirror 8 has a hole through which the waveguide 9 passes.

  Further, in order to supply operating power from the fixed unit 3 to the rotating unit 2 using electromagnetic force, a power transmitting module 20 is provided in the fixed unit 3 and a power receiving module 21 is provided in the rotating unit 2 so as to face each other. ing.

  The operation of the electric surveillance camera 1 configured as described above will be described below. First, the waveguide 9 is at the axis of the rotating unit 2 and is held so as to rotate integrally with the rotating unit 2. Using this waveguide 9 as a first optical transmission line, a laser diode portion 6 disposed at one end and a fixed portion side light receiving element 10 disposed at the other end form a first optical transmission system. . This first optical transmission system is used for transmission of a video signal having a wide frequency range. Further, the space around the waveguide 9 is used as a second transmission path, and the second light transmission is performed by the laser diode section 18, the fixed section side mirror 8, the rotating section side mirror 7, and the rotating section side light receiving element 19. A system is formed. This second optical transmission system is used for transmission of control signals.

  Next, the power supply circuit 14 supplies operating power to the electrical elements housed in the fixed unit 3 and is housed in the rotating unit 2 via the power transmission module 20 and the power reception module 21 facing each other. Driving electric power is supplied to each electric element. When the control circuit 13 receives a control signal for driving the rotating unit 2 in the horizontal direction via the network circuit 28, the control circuit 13 applies the control signal to the driving unit 26. The driving unit 26 drives the pan motor 25 to rotate the rotating unit 2. When the control circuit 13 receives a parallel control signal for driving the camera 4 in the vertical direction via the network circuit 28 or receives a parallel control signal for the camera 4, the control circuit 13 converts the control signal into parallel-serial. It adds to the conversion part 16. The parallel-serial converter 16 converts the parallel control signal into a serial signal and applies it to the E / O converter 17. As a result, the serial control signal is converted into an optical signal and emitted from the laser diode unit 18. The emitted optical signals are sequentially reflected by the fixed portion side mirror 8 and the rotating portion side mirror 7 that penetrate the waveguide 9 at the center, and are received by the rotating portion side light receiving element 19. The rotating portion side light receiving element 19 applies an electrical camera control signal to the camera 4. In addition, an electrical control signal for driving the camera 4 in the vertical direction is applied to the drive unit 23. The drive unit 23 drives the tilt motor 22 to rotate the camera 4. Although the light transmission efficiency is significantly reduced by two reflections at the fixed portion side mirror 8 and the rotating portion side mirror 7 having the waveguide 9 penetrated through the central portion, the light is transmitted from the fixed portion 3 to the rotating portion 2. Since the amount of signal to be transmitted is much smaller than the amount of signal transmitted from the rotating unit 2 to the fixed unit 3, it is possible to secure a sufficient transmission path for the necessary signal amount. At this time, a lens may be provided on the front surface of the laser diode portion 18 and the front surface of the rotating portion side light receiving element 19 so that the signal light is efficiently transmitted.

  Next, the camera 4 is a high-definition camera of, for example, SXGA (the number of scanning lines 1280 × the number of horizontal samples 960) and 30 fps, and outputs RGB parallel video signals each having 8 bits. This video signal is added to the parallel-serial conversion unit 5, where it is converted into a serial video signal, further 8B-10B converted, and added to the laser diode unit 6. The transmission rate of the 8B-10B converted video signal is about 1.1 Gbps. The laser diode unit 6 converts it into signal light whose intensity is modulated by a serial signal. Since the frequency response of the laser diode unit 6 can easily obtain a performance of about several gigahertz, data transmission of about 1.1 Gbps can be performed with a margin. The signal light emitted from the laser diode section 6 is incident on one end of a waveguide 9 provided in the rotating shaft core section. At this time, since the light at the center of the laser diode unit 6 having a large light emission power is incident on the waveguide 9, an optical signal can be transmitted efficiently. A lens may be provided on the front surface of the laser diode unit 6 so that more light is sent into the waveguide 9. The inner wall of the waveguide 9 is subjected to a reflective process, and the signal light incident from one end travels toward the other end. Since the waveguide 9 penetrates the rotating part side mirror 7 and the fixed part side mirror 8, it is not affected by the signal light reflected by the rotating part side mirror 7 and the fixed part side mirror 8. The signal light traveling through the waveguide 9 is emitted from the other end to the fixed portion 3 side.

  The signal light emitted from the waveguide 9 is received by the fixed portion side light receiving element 10. At this time, a configuration may be adopted in which signal light is efficiently collected on the stationary part side light receiving element 10 by using a condensing means such as a lens on the front surface of the stationary part side light receiving element 10. The signal light received by the fixed portion side light receiving element 10 is converted into an electric signal by the O / E converter 11 and added to the serial-parallel converter 12. The serial-parallel converter 12 performs 10B-8B conversion on the serial electrical signal added thereto, converts it into an RGB parallel signal of the camera 4, and adds the demodulated video signal to the image processing circuit 27. The image processing circuit 27 performs well-known image compression and the like and applies it to the network circuit 28. The network circuit 28 transmits the video signal subjected to signal processing to a PC or a monitor via a cable connected to the video output connector 15. By these processes, the video signal of the camera 4 is recorded or reproduced.

  FIG. 2 is a view showing an attachment mechanism that prevents a decrease in optical power accompanying a relative positional shift of the optical system that is likely to occur when the rotating unit 2 is rotated. In FIG. 2, the laser diode unit 6, the rotating unit side mirror 7, the rotating unit side light receiving element 19 and the waveguide 9 are integrally held by the rotating unit side holding member 31 on the rotating unit 2 side, and on the fixed unit 3 side. Is configured so that the fixed portion side mirror 8, the fixed portion side light receiving element 10, and the laser diode portion 18 are integrally held by a fixed portion side holding member 32. At this time, the fixed portion side holding member 32 supports the waveguide 9 so as to be rotatable.

  As described above, according to the first embodiment, an optical signal is transmitted from the laser diode portion 6 to the fixed portion side light receiving element 10 using the axial core portion of the through hole 30 as the first optical transmission path, while the through hole is provided. A laser diode unit 18 is provided through a fixed portion side mirror 8 and a rotating portion side mirror 7 provided in the second optical transmission path, with a peripheral region off the 30 axis portion serving as a second optical transmission path. The optical power of the first optical transmission path is not damaged by the second optical member and the first optical member, because the optical signal is transmitted from the optical device to the rotating portion side light receiving element 19. Thus, a transmission device suitable for an electric surveillance camera that performs asymmetric bidirectional optical transmission is provided.

  In the first embodiment, the rotating portion side holding member 31 on the rotating portion 2 side holds the waveguide 9 and the fixed portion side holding member 32 rotatably supports the waveguide 9. On the contrary, the fixed portion side holding member 32 on the fixed portion 3 side may hold the waveguide 9, and the rotating portion side holding member 31 may be configured to rotatably support the waveguide 9. In the first embodiment, the rotating part side holding member 31 integrally holds the laser diode part 6, the rotating part side mirror 7, and the rotating part side light receiving element 19, and the fixed part side holding member 32 is fixed. The part-side light receiving element 10, the fixed part-side mirror 8 and the laser diode part 18 are integrally held, but at least the rotating part-side mirror 7 and the rotating part-side light receiving element 19 having a large positional deviation are integrated by the rotating part-side holding member 31. Even if the fixed part side mirror 8 and the laser diode part 18 are integrally held by the fixed part side holding member 32, the reduction of the optical power accompanying the rotation of the rotating part 2 can be suppressed slightly. it can.

  In the first embodiment, a large-diameter optical fiber is used as the waveguide 9. However, if the optical fiber has a function of receiving signal light from one end and guiding it to the other end while rotating, the diameter may be May be a few hundred microns to a few millimeters. In short, as long as high positional accuracy is not required for optical coupling, a material other than an optical fiber may be used. The conventional optical fiber used for communication is several tens of microns to several hundreds in order to prevent the transmission frequency band from being limited by the delay spread caused by passing through the fiber through a plurality of paths. Although it is set to micron, since the fiber length is about several centimeters in this embodiment, the delay spread does not cause a problem. For example, even in the case of 10 Gbps high-speed data transmission, the problem due to the band limitation does not occur.

<Second Embodiment>
FIG. 3 is a view showing an attachment mechanism for preventing a decrease in optical power by rotation of the rotating unit 2 as a second embodiment of the transmission apparatus according to the present invention, as in FIG. In the figure, the same elements as those in FIG. In this embodiment, the waveguide 9 in FIG. 1 or FIG. 2 is removed, and instead, a lens 33 is provided on the front surface of the laser diode unit 6 to collimate the signal light from the laser diode unit 6 into parallel light, Further, a lens 34 is provided on the front surface of the fixed portion side light receiving element 10 so that parallel light is condensed and received by the fixed portion side light receiving element 10. In this case, as shown in FIG. 4A, a through hole 35 may be provided in the rotating part side mirror 7 and the fixed part side mirror 8, or as shown in FIG. Only the central part may be the transparent part 36. As a modification of the second embodiment, as shown in FIG. 4C, a reflection film 37 is formed at the center and the periphery thereof is made transparent so that the transmission system and control of the video signal are controlled. The signal transmission system can also be replaced. In this case, the laser diode part 6 and the rotating part side light receiving element 19 of the rotating part 2 may be replaced, and the fixed part side light receiving element 10 and the laser diode part 18 of the fixing part 3 may be replaced.

  As described above, according to the second embodiment, an optical signal is transmitted from the laser diode unit 6 to the fixed portion side light receiving element 10 using the axial core portion of the through hole 30 as the first optical transmission path, while the through hole is provided. A laser diode unit 18 is provided through a fixed portion side mirror 8 and a rotating portion side mirror 7 provided in the second optical transmission path, with a peripheral region off the 30 axis portion serving as a second optical transmission path. The optical power of the first optical transmission path is not damaged by the second optical member and the first optical member, because the optical signal is transmitted from the optical device to the rotating portion side light receiving element 19. Thus, a transmission device suitable for an electric surveillance camera that performs asymmetric bidirectional optical transmission is provided.

  In the first and second embodiments described above, the surrounding area outside the axial core portion of the through hole 30 is used as the second optical transmission path. However, when the through hole 30 is wide, the axial core is used. Even if a part of the area outside the part is used as the second optical transmission line, a transmission apparatus having performance according to the first and second embodiments is provided.

  According to the present invention, an optical signal is transmitted from the rotating part to the fixed part by the rotating part side light emitting element and the fixed part side light receiving element, and the fixed part side light emitting element, the fixed part side optical member, the rotating part side optical member, and the rotating part. Since the optical signal can be transmitted from the fixed part to the rotating part by the side light receiving element, it can be applied to an electric surveillance camera that performs asymmetric bidirectional optical transmission.

It is a schematic block diagram of 1st Embodiment of the electric surveillance camera which accommodated the transmission apparatus which concerns on this invention. It is the figure which showed the attachment mechanism of the optical system of the 1st Embodiment of this invention. It is the figure which showed the attachment mechanism of the optical system of the 2nd Embodiment of this invention. It is the perspective view which showed the structural example of the rotation part side mirror of the 2nd Embodiment of this invention, and a fixed part side mirror. It is a schematic block diagram of the conventional electric surveillance camera. It is sectional drawing which shows the detailed structure of the coupling | bond part of the conventional electric surveillance camera.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric surveillance camera 2 Rotating part 3 Fixed part 4 Camera 6 Laser diode part (1st light emitting element)
7 Rotating part side mirror (first optical member)
8 Fixed part side mirror (second optical member)
9 Waveguide 10 Light receiving element on fixed side (second light receiving element)
18 Laser diode part (second light emitting element)
19 Rotating part side light receiving element (first light receiving element)
DESCRIPTION OF SYMBOLS 20 Power transmission module 21 Power receiving module 30 Through-hole 31 Rotating part side holding member 32 Fixed part side holding member 33, 34 Lens 35 Through hole 36 Transparent part 37 Reflective film

Claims (1)

It is housed in a rotating part that is rotatably coupled to the fixed part via a fixed part side device accommodated in a fixed part fixed to a predetermined member and a coupling part having a through-hole penetrating in the rotation axis direction. The rotating unit side device transmits the optical signal bidirectionally through the first optical transmission path extending to the axial core portion of the through hole and the second optical transmission path extending around the axial core portion. A transmission device for
The rotating unit side device is:
A first light emitting element that emits signal light to the first optical transmission line;
A first light receiving element mounted at a position deviated radially outward from the through hole;
A first optical member that causes the first light receiving element to receive a light by changing a path of the signal light traveling through the second optical transmission path;
The fixed part side device is:
A second light receiving element for receiving signal light traveling through the first optical transmission line;
A second light emitting element that is mounted at a position that is radially outward from the through hole and emits signal light radially inward;
A transmission apparatus comprising: a second optical member that changes a path of signal light emitted from the second light emitting element and travels to the second optical transmission path.

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