JP5338388B2 - Rotary joint and light guide member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent generation of crosstalk without separately providing a light shielding member in a rotary joint which transmits bidirectional optical signals between a fixing member and a rotating member. <P>SOLUTION: The rotary joint 1 has: the fixing member 3; the rotating member 2 freely rotatable to the fixing member 3; a light guide member 10a with reflecting surfaces 14a, 4b and provided in the fixed member 3; a light guide member 10b similarly provided in the rotating member 2; a light emitting element 11a provided in the fixing member 3; a light receiving element 12a provided in the fixing member 10a at a position where the signal light emitted by the light emitting element 11a can not be received; a light emitting element 11b and a light receiving element 12b similarly provided in the rotating member 3, and is constituted so that the signal light emitted by the light emitting element 11a is reflected on the reflection surface 14a, etc. to be received by the light receiving element 12b, while the signal light emitted by the light emitting element 11b is reflected by the reflection surface 14b, etc. to be received by the light receiving element 12a. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a rotary joint and a light guide member, and in particular, among a rotary joint and a light guide member that perform signal transmission between a fixed member and a rotary member that is rotatably combined with the fixed member. The present invention relates to a device that performs bidirectional signal transmission.

  Many surveillance camera devices that are fixedly installed on an indoor ceiling or the like that perform monitoring while changing the imaging direction by controlling the pan angle and tilt angle of the camera are widely used. Such a surveillance camera device capable of angle control has a configuration in which a fixed part fixedly installed on a ceiling or the like and a movable part rotatable in the pan direction are connected via an electric pan head. There are many things.

  That is, in the surveillance camera device, a movable part equipped with a camera equipped with a tilt drive mechanism that rotates in the tilt direction is attached to one (movable part) of the electric pan head that can rotate in the pan direction, and the electric cloud. In many cases, the other (fixed part) of the base is attached to one of the fixed parts, and the other fixed part is fixedly installed on the ceiling or the like.

  In the surveillance camera device having such a configuration, the video signal output from the camera mounted on the movable unit is transmitted to the fixed unit via the electric camera platform, and image processing and output interface conversion are performed in the fixed unit. After that, it is output to an external monitor or video signal recording device.

  Several methods are known for the electric camera platform used in such a monitoring camera device. Particularly, as an electric camera platform capable of continuously turning the movable part in the pan direction, a slip ring, It is known that a signal connection path extending between the swivel portion and the fixed portion is constructed by a sliding contact with the brush.

  However, the sliding contact method using a slip ring makes the electrical contact unstable due to oil film and dust adhering to the contact part between the rotating slip ring and the fixed brush, and noise accompanying mechanical contact. There are problems such as generation and deterioration of electrical contact performance due to long-term continuous sliding. In particular, the generation of noise due to rotation is a problem in video signals, and the occurrence of malfunctions is a problem in control signals such as pan and tilt control. Furthermore, since the frequency band that can be transmitted is limited in such a mechanical contact method, it is difficult to transmit high-definition video signals and high-speed data.

  Therefore, in order to avoid the adverse effect of the sliding contact between the slip ring and the brush, there has been proposed an optical transmission system that performs non-contact signal transmission using an optical signal. These proposals were originally one-way transmission that transmits the video signal of the camera provided in the rotating part to the fixed side, but sometimes the camera or tilt motor control signal is sent from the fixed side to the rotating side, Proposals have been made to transmit non-contact optical signals in both directions.

  For example, in Patent Document 1, two sets of light emitting elements and light receiving elements are used, and the light receiving elements on the fixed side and the rotating side are arranged opposite to each other at substantially the center of the rotation axis, and outside each light receiving element. Rotating the light by arranging the light emitting element so that it does not overlap with the light receiving element and projecting the light beam of the light emitting element from the light emitting element toward the center of each counterpart light receiving element from an oblique direction A coupling device has been proposed.

  However, in the optical rotation coupling device described in Patent Document 1, in a bidirectional optical transmission path, the light from the light emitting element is arranged to be incident from an oblique direction with respect to the light receiving element arranged at the rotation center. However, since interference of optical signals occurs with each other, there is a problem that a new light shielding member is required to reduce the interference.

  In other words, interference can be reduced by using a VCSEL (surface emitting laser) or LD (laser diode) with a very narrow radiation angle, but generally when using an LED (light emitting diode) cheaper than the VCSEL or LD. Even if the radiation angle is narrowly directional type, it has a full width of dozens of degrees, and the signal light is emitted with a spread and irradiated to the periphery of the light receiving element, but not only the reflected light but also the interference of the optical signal due to scattering and stray light Will cause. In addition, it is difficult to ensure light isolation when rotating and stationary LEDs having the same wavelength and radiation angle are used to reduce production costs and improve production efficiency by sharing parts. If a light shielding member is used as proposed in Patent Document 1, interference can be prevented even if the rotating side and the fixed side LED are the same, but the cost of the light shielding member including the initial investment of the mold or the like is low. There is a problem that it takes.

  As described above, the rotary coupling device using the optical signal compensates for the drawbacks of the conventional sliding contact type, but securing the light isolation has been a problem. Regarding this point, for example, in the optical branching element in Patent Document 2, a method of reducing the crosstalk of the optical signal by devising the angle between the transmission light reflection surface and the reception light reflection surface has been proposed.

  An optical branching element 210 described in Patent Document 2 as shown in FIG. 20 has an opening surface 211a that faces an end surface of an optical fiber (not shown) in order to prevent reflection of transmission light from entering the reception path. A transmission surface that reflects the transmission light incident from the opposing surface 211b of the light emitting element (not shown), the opposing surface 211c of the light receiving element (not shown), and the opposing surface 211b of the light emitting element toward the opening surface 211a. A side reflection surface 211d-1 and a reception side reflection surface 211e-1 for reflecting the reception light incident from the opening surface 211a toward the opposing surface 211c of the light receiving element are provided. 20 (a) is a perspective view of the optical branching element 210, FIG. 20 (b) is a front view of the optical branching element 210, and is a view as seen from the arrow B in FIG. 20 (a). 20 (c) is a plan view of the optical branching element 210, and is a view taken in the direction of arrow C in FIG. 20 (a). FIG. 20 (d) is a right side view of the optical branching element 210. It is a D arrow line view in Fig.20 (a).

  When the optical axis direction of the optical fiber is the Z-axis, the opposing direction of the surface 211b and the surface 211c is the X-axis, and the direction orthogonal to the X-axis and the Z-axis is the Y-axis, the transmission-side reflective surface 211d-1 is the opening surface 211a. Parallel planes are inclined by rotating around the Y-axis and X-axis, and the reception-side reflection surface 211e-1 is parallel to the opening surface 211a and the transmission-side reflection surface 211d-2 is around the Y-axis. The surface is inclined by rotating in the opposite direction. The main direction of the transmission light reflection path and the main direction of the reception path in the vicinity of the opening surface 211a can be greatly separated.

JP 2001-44940 A JP 2005-345629 A

  However, the configuration of Patent Document 2 is described in paragraph [0009] of this document as “a light emitting diode (LED) having a large light emitting area, a large aperture optical fiber having a large NA, and the like. In many cases, off-axis rays are widely distributed around the light source, so that some off-axis rays actually enter even if crosstalk does not enter the light-receiving surface in the figure. As described above, it is assumed that a lens surface is formed on the surface of the optical branching element 210 to collimate the signal light. Here, in Patent Document 2, the optical branching element 210 has a transparent block shape. When the optical branching element 210 is actually manufactured, a method by cutting and a method by molding can be roughly divided. A method suitable for mass production at a low cost is the latter method.

  However, since the shape of the optical branching element 210 is a shape in which a lens surface is further formed in a portion where the difference between the thick and thin portions is large, a mold opening / closing surface corresponding to the necessary lens surface is required. Accurate molding conditions are required, which is expensive in terms of mold manufacturing costs and molded product yield. In addition, in the optical branching element 210 described in Patent Document 2, a shape without an acute angle portion has been proposed in consideration of moldability, but the area of the reflecting surface is reduced by the amount of the elimination of the acute angle portion. Minutes will miss off-axis rays.

  In other words, it is not suitable for a manufacturing method that can be mass-produced at low cost, and the cost of mold manufacturing is high, and the yield due to the necessity of high-precision molding conditions is high, and when manufacturing by molding, it may be expensive. It was a problem.

  Moreover, in the thing of patent document 2, the light emitting element and light receiving element which were installed in the fixing | fixed part (fixing member) are arrange | positioned on the same axis | shaft, and the light emitting element and the light receiving element are mutually opposed. Therefore, part of the signal light emitted from the light emitting element may enter the light receiving element without being reflected by the optical branching element 210, thereby causing crosstalk of the signal light (the light emitting element of the fixing member is There is a problem that the emitted signal light may be received by the light receiving element of the fixed member.

  More specifically, as shown in FIG. 16 of Patent Document 2, a light emitting element and a light receiving element are installed on a fixed member, and another light emitting element and a light receiving element are also installed on a movable part (rotating member). The signal light emitted from the light emitting element installed on the light is reflected by each optical branching element 210 and received by the light receiving element on which the rotating member is installed, but the isolation is not sufficient (installed on the fixed member). In some cases, the signal light emitted from the light emitting element is not reflected by the optical branching element 210), causing interference of the signal light. That is, there is a problem that crosstalk may occur when signal light emitted from the light emitting element of the fixing member enters the light receiving element installed on the fixing member.

  Similarly, the light emitting element and the light receiving element installed on the rotating member are also arranged on the same axis, which may cause a crosstalk.

  The present invention has been made in view of the above problems, and in a rotary joint and a light guide member for transmitting a bidirectional optical signal between a fixed member and a rotating member, a cross member is not provided without a separate light shielding member. An object is to provide a device capable of preventing the occurrence of talk.

  According to a first aspect of the present invention, there is provided a fixing member, a rotating member that is rotatably provided on the fixing member about a predetermined axis, and a first reflecting surface and a second reflecting surface, the fixing member A rotating member-side light guide member provided on the rotating member, and the fixing member or the fixing member side, the fixing member-side light guiding member provided on the rotating member, a third reflecting surface, and a fourth reflecting surface A fixed-member-side light receiving element provided on the fixed member or the fixed-member-side light guide member at a position where the fixed-member-side light-emitting element provided on the light guide member and the signal light emitted from the fixed-member-side light emitting element cannot be received An element, a rotating member side light emitting element provided on the rotating member or the rotating member side light guide member, and a position where the signal light emitted from the rotating member side light emitting element cannot be received at the rotating member or the rotating member side Rotation provided on the light guide member Signal light emitted from the fixing member side light emitting element is reflected by the first reflecting surface of the fixing member side light guide member, and the fourth light of the rotating member side light guide member is provided. The signal light reflected by the reflecting surface and received by the rotating member-side light receiving element and emitted by the rotating member-side light emitting element is reflected by the third reflecting surface of the rotating member-side light guide member, and the fixed member side The rotary joint is configured to be reflected by the second reflecting surface of the light guide member and received by the light receiving element on the fixed member side.

  A second invention includes a fixing member, a rotating member rotatably provided on the fixing member with a predetermined axis as a rotation center, a first reflecting surface and a second reflecting surface, and the fixing member A fixed member side light guide member provided on the rotation member, a third reflection surface and a fourth reflection surface, a rotation member side light guide member provided on the rotation member, and an optical axis of the rotation center axis In such a manner as to intersect, the fixing member side light emitting element provided on the fixing member or the fixing member side light guide member, and the optical axis intersect with the rotation center axis and the optical axis of the fixing member side light emitting element. The fixed member side light receiving element provided on the fixed member or the fixed member side light guide member and the rotating member or the rotary member side light guide member so that the optical axis intersects the rotation center axis. The rotating member side light emitting element provided and the optical axis is the rotation center And a rotating member side light receiving element provided on the rotating member or the rotating member side light guide member so as to intersect the optical axis of the rotating member side light emitting element, and the fixed member side light emitting element emits light. The reflected signal light is reflected by the first reflecting surface of the stationary member side light guide member, reflected by the fourth reflecting surface of the rotating member side light guide member, and received by the rotating member side light receiving element, The signal light emitted from the rotating member-side light emitting element is reflected by the third reflecting surface of the rotating member-side light guide member, and reflected by the second reflecting surface of the fixing member-side light guide member, so that the fixed member side is reflected. This is a rotary joint configured to be received by a light receiving element.

  According to a third invention, in the first invention or the second invention, the fixed member side light guide member and the rotating member side light guide member are configured to have the same specifications, or the fixed member side light emission. The element and the rotating member side light emitting element are configured with the same specifications, or at least the fixed member side light receiving element and the rotating member side light receiving element are configured with the same specifications. It is the rotary joint which has any aspect.

  According to a fourth invention, in any one of the first to third inventions, the signal light emitted from the fixing member side light emitting element is converged between the fixing member side light emitting element and the first reflecting surface. A first lens for focusing the signal light received by the fixed member side light receiving element between the fixed member side light receiving element and the second reflecting surface, the rotating member side A third lens for converging the signal light emitted by the rotating member-side light emitting element between the light emitting element and the third reflecting surface, the rotating member-side light receiving element and the fourth reflecting surface The rotary joint is provided with at least one of the fourth lenses for converging the signal light received by the rotating member side light receiving element.

  According to a fifth invention, in any one of the first to fourth inventions, the light guide member is a molded product integrally formed of a material that transmits signal light, and a part of an outer surface of the light guide member. The signal light that has entered the light guide member is reflected by the reflection surface formed by another part of the outer surface of the light guide member, and the reflected signal light is reflected on the outer surface of the light guide member. It is comprised so that it may go out of the said light guide member from further another part, and the minor angle of the crossing angles in two surfaces which form the ridgeline part of the said light guide member is the said light guide member It is a rotary joint which is 45 degrees or more in all the ridge lines.

  6th invention is a rotary joint which has a slip ring which supplies electric power from the said fixing member to the said rotation member in any one of the 1st-5th invention.

  A seventh invention is a light guide member used when transmitting an optical signal between a fixed member and a rotary member provided rotatably on the fixed member with a predetermined axis as a rotation center. A first light guide portion formed in a cylindrical shape having an outer diameter smaller than that of the first light guide portion, and coaxial with an axis of the first light guide portion. A second light guide part protruding from one end face in the axial direction of the part, and a circle whose inner diameter is smaller than the outer diameter of the first light guide part and larger than the outer diameter of the second light guide part It is formed in a column shape, is coaxial with the axis of the first light guide part, and is recessed from the other end surface in the axial direction of the first light guide part to an intermediate part in the axial direction of the first light guide part. Provided on the bottom of the recess, provided on the bottom of the recess, and provided on the bottom of the recess. A light guide member having a flat second reflecting surface intersecting the axis and the first reflection surface and the oblique light guide section.

  According to the present invention, in the rotary joint and the light guide member that transmit bidirectional optical signals between the fixed member and the rotating member, the occurrence of crosstalk can be prevented without providing a separate light shielding member. .

It is a figure which shows schematic structure of the surveillance camera 5 carrying the rotary joint 1 which concerns on embodiment of this invention. It is the figure which showed the structure of the bidirectional | two-way signal light transmission of the rotary joint. It is the figure which showed reflection of the optical signal in light guide member 10a, 10b among the structures of the bidirectional | two-way signal light transmission used for the rotary joint 1. FIG. It is a figure explaining the effect by the external shape of the light guide members 10a and 10b used for the rotary joint 1 being circular. It is a figure which shows the manufacturing method of the light guide members 10a and 10b used for the rotary joint 1. FIG. It is an example of a positioning shape with the circuit board which mounted light guide members 10a and 10b used for rotary joint 1. It is a figure which shows the shape of the metal mold | die which forms the site | part of the reflective surface 14 of the light guide members 10a and 10b used for the rotary joint 1. FIG. It is sectional drawing shown about the shape of the light guide members 10a and 10b used for the rotary joint 1. FIG. It is explanatory drawing in case the light guide members 10a and 10b used for the rotary joint 1 are provided with the holding part and lens surface of an optical component. Of the structural examples of the rotary joint 1, this is an example in which sliding contact transmission is combined with bidirectional optical transmission by processing. It is a figure of the rotation side assembly of the example shown in FIG. It is the modification which combined sliding contact transmission in addition to bidirectional | two-way optical transmission among the structural examples of the rotary joint 1. FIG. It is a figure which shows the angle of each reflective surface 14a, 14b, 14c, 14d of the light guide member 10a, 10b. It is a figure which shows the angle of each reflective surface 14a, 14b, 14c, 14d of the light guide member 10a, 10b. It is sectional drawing of the metal mold | die of the light guide members 10a and 10b. It is a figure which shows the modification of light guide member 10a, 10b. It is a figure which shows the positional relationship of the light guide members 10a and 10b, light emitting element 11a, 11b, and light receiving element 12a, 12b when it sees from the direction of the rotation center axis | shaft 4. FIG. It is a figure which shows the modification of installation forms, such as light emitting element 11a, 11b. It is a figure which shows the modification of light guide members 10a and 10b. It is a figure which shows the conventional optical branch element 210. FIG.

  FIG. 1 is a diagram showing a schematic configuration of a surveillance camera 5 equipped with a rotary joint 1 according to an embodiment of the present invention.

  2 is a diagram showing a configuration of bidirectional signal light transmission of the rotary joint 1, and FIG. 3 is an optical signal in the light guide members 10a and 10b in the configuration of bidirectional signal light transmission used for the rotary joint 1. It is the figure which showed reflection of.

  FIG. 4 is a diagram for explaining the effect of the outer shape of the light guide members 10a and 10b used in the rotary joint 1 being circular.

  FIG. 5 is a diagram illustrating a method for manufacturing the light guide members 10 a and 10 b used in the rotary joint 1.

  6 is an example of a positioning shape with a circuit board on which the light guide members 10a and 10b used for the rotary joint 1 are mounted, and FIG. 7 is a part of the reflecting surface 14 of the light guide members 10a and 10b used for the rotary joint 1. FIG. 8 is a cross-sectional view showing the shapes of the light guide members 10a and 10b used in the rotary joint 1. FIG.

  As shown in FIG. 1, a fixed portion (fixed member) 3 attached to a ceiling or the like, a rotating portion (rotating member) 2 that mounts a camera and rotates around a pan rotation axis 4, and the fixed portion 3 pans the rotating portion 2. There is a rotary joint 1 that is rotatably held around a rotating shaft 4.

  The rotary joint 1 performs signal transmission and power supply while holding the rotating unit 2 rotatably. In the case of the surveillance camera 5, in addition to transmitting camera-captured images from the rotating unit 2 to the fixed unit 3, it is fixed for a camera control signal and a tilt rotation motor control signal often mounted on the rotating unit 2. Signal transmission from the unit 3 to the rotating unit 2 is also necessary. In the rotary joint 1, bidirectional optical transmission and sliding contact transmission are used in combination, the video signal and control signal signal systems use optical transmission, and the power supply uses sliding contact transmission.

  More specifically, the rotary joint 1 is an example of a fixing member 3, a rotating member 2, a fixing member side light guide member 10a that is an example of a light guide means, a rotating member side light guide member 10b, and a light emitting means. For example, a fixed member side light emitting element 11a configured by a light emitting diode (LED), an example of a light receiving means, for example, a fixed member side light receiving element 12a configured by a photodiode (PD), and a rotating member side configured similarly. The light emitting element 11b and the rotating member side light receiving element 12b are provided.

  The rotating member 2 is supported by the fixing member 3 via a bearing (not shown), and is provided on the fixing member 3 so as to be rotatable about a predetermined axis 4 (infinitely rotatable in both directions). The rotational positioning of the rotating member 2 is performed by an actuator such as a motor (not shown) under the control of a control device (not shown). The fixed member-side light guide member 10 a includes the reflecting surfaces 14 (14 a and 14 b) and is provided integrally with the fixed member 3. The rotating member-side light guide member 10b includes the reflecting surfaces 14 (14c, 14d) and is provided integrally with the rotating member 2.

  The fixing member side light emitting element 11a is provided integrally with the fixing member 3, the rotating member side light emitting element 11b is provided integrally with the rotating member 2, and the fixing member side light receiving element 12a is provided with the fixing member 3. The rotating member side light receiving element 12b is provided integrally with the rotating member 2, but the fixed member side light emitting element 11a is provided integrally with the fixed member side light guide member 10a. The rotating member side light emitting element 11b may be integrated with the rotating member side light guide member 10b, or the fixed member side light receiving element 12a may be fixed to the fixed member side light guide. The structure provided integrally with the member 10a may be sufficient, and the structure by which the rotation member side light receiving element 12b is provided integrally with the rotation member side light guide member 10b may be sufficient (for details, FIG. 9). Later).

  The fixed member side light receiving element 12a is installed at a position where the signal light emitted from the fixed member side light emitting element 11a cannot be received.

  That is, in the case of assuming a space in which optical characteristics such as a refractive index are uniform (for example, a space in which only air exists) without blocking the signal light emitted from the fixed member side light emitting element 11a, the fixed member side light emission is assumed. The presence of the fixed member side light receiving element 12a outside the irradiation region of the element 11a (the irradiation region defined by the irradiation angle of the light emitting element and the distance from the light emitting element), and the light receiving region of the fixed member side light receiving element 12a The fixing member side is set so as to satisfy at least one of the conditions that the fixing member side light emitting element 11a exists outside the (light receiving area represented by the light receiving angle of the light receiving element and the distance from the light receiving element). A light emitting element 11a and a fixed member side light receiving element 12a are provided.

  Similarly, the rotating member side light receiving element 12b is disposed at a position where the signal light emitted from the rotating member side light emitting element 11b cannot be received.

  In the rotary joint 1, the signal light emitted from the fixed member side light emitting element 11a is reflected by the reflective surface 14a of the fixed member side light guide member 10a and reflected by the reflective surface 14d of the rotary member side light guide member 10b. The rotating member side light receiving element 12b is configured to receive light. Further, the signal light emitted from the rotating member side light emitting element 11b is reflected by the reflecting surface 14c of the rotating member side light guide member 10b and reflected by the reflecting surface 14b of the fixing member side light guiding member 10a to be fixed member side light receiving elements. 12a is configured to receive light.

  Here, the form of installation of the light emitting elements 11a and 11b and the light receiving elements 12a and 12b will be described in more detail with examples.

  The fixing member side light emitting element 11a is located at a position away from the rotation center axis 4 so that the optical axis intersects the rotation center axis 4 (for example, the optical axis is substantially perpendicular to the rotation center axis 4). Is provided. In addition, the signal light emission part of the fixing member side light emitting element 11a faces the rotation center axis 4 side. That is, the fixed member side light emitting element 11a emits signal light toward the rotation center axis 4 side.

  The fixed member side light receiving element 12a is arranged such that this optical axis intersects with the rotation center axis 4 and the optical axis of the fixed member side light emitting element 11a (for example, the optical axis of the rotation center axis 4 and the fixed member side light emitting element 11a). It is provided at a position away from the rotation center axis 4 so as to be substantially orthogonal to the optical axis. The signal light receiving part of the fixed member side light receiving element 12a faces the rotation center axis 4 side. That is, the fixed member side light receiving element 12a receives the signal light transmitted from the rotation center axis 4 side.

  Further, as already understood, the rotation center axis 4, the optical axis of the fixed member side light emitting element 11a, and the optical axis of the fixed member side light receiving element 12a extend so as to intersect each other at one point. The optical axis of the side light emitting element 11 a and the optical axis of the fixed member side light receiving element 12 a are shifted from each other, and the fixed member side light emitting element 11 a and the fixed member side light receiving element 12 a are not opposed to the rotation center axis 4. Is arranged.

  By the way, the rotation center axis 4, the optical axis of the fixed member side light emitting element 11a, and the optical axis of the fixed member side light receiving element 12a may extend without intersecting at one point. That is, the optical axis of the fixed member side light emitting element 11a may extend at a twisted position with respect to the rotation center axis 4, and the optical axis of the fixed member side light receiving element 12a is the light emission of the rotation center axis 4 and the fixed member side. It may extend at a twisted position with respect to the optical axis of the element 11a.

  The rotating member side light emitting element 11b and the rotating member side light receiving element 12b are also provided in the same manner as the fixed member side light emitting element 11a and the fixed member side light receiving element 12a. Note that the optical axis of the rotating member side light emitting element 11b and the optical axis of the rotating member side light receiving element 12b are the optical axis of the fixed member side light emitting element 11a and the fixed member side in the direction of the rotation center axis 4 (vertical direction in FIG. 2). It is away from the optical axis of the light receiving element 12a.

  In the rotary joint 1, the control signal of the camera or the like is converted by a conversion circuit (not shown), emitted as a light signal from the fixing member side light emitting element 11 a, and the signal light emitted from the fixing member side light emitting element 11 a The signal light enters the fixed member side light guide member 10a from the signal light incident surface 31a of the light guide member 10a, and the entered signal light travels through the fixed member side light guide member 10a to reflect the reflection surface 14a of the fixed member side light guide member 10a. The reflected signal light travels in the fixed member side light guide member 10a along the rotation center axis 4 and is emitted from the signal light entrance / exit surface 13a of the fixed member side light guide member 10a. ing.

  Further, the signal light emitted from the signal light entrance / exit surface 13a enters the rotation member side light guide member 10b from the signal light entrance / exit surface 13b of the rotation member side light guide member 10b, and the entered signal light is guided to the rotation member side light guide. The signal light travels along the rotation center axis 4 in the optical member 10b, and the advanced signal light is reflected by the reflecting surface 14d of the rotation member side light guide member 10b. The reflected signal light is guided to the rotation member side light guide. The light travels through the member 10b, is emitted from the signal light emitting surface 32b of the rotating member side light guide member 10b, and is received by the rotating member side light receiving element 12b.

  Similarly, a video signal photographed by the camera is converted by a conversion circuit (not shown), emitted as an optical signal from the rotating member side light emitting element 11b, and signal light emitted from the rotating member side light emitting element 11b is guided to the rotating member side light guide. The signal light enters the rotating member side light guide member 10b from the signal light incident surface 31b of the member 10b, and the entered signal light travels through the rotating member side light guide member 10b and is reflected by the reflecting surface 14c of the rotating member side light guide member 10b. The reflected signal light travels along the rotation center axis 4 in the rotating member side light guide member 10b and is emitted from the signal light entrance / exit surface 13b of the rotating member side light guide member 10b. .

  Further, the signal light emitted from the signal light entrance / exit surface 13b enters the fixed member side light guide member 10a from the signal light entrance / exit surface 13a of the fixed member side light guide member 10a, and the entered signal light is guided to the fixed member side light guide. The signal light travels along the rotation center axis 4 in the optical member 10a, and the advanced signal light is reflected by the reflecting surface 14b of the fixed member side light guide member 10a, and the reflected signal light is guided by the fixed member side light guide. Proceeding inside the member 10a, the light is emitted from the signal light emitting surface 32a of the fixed member side light guide member 10a, and is received by the fixed member side light receiving element 12a.

  By the way, in the rotary joint 1, the fixed member side light guide member 10a and the rotation member side light guide member 10b are made common and configured with the same specifications. Moreover, the fixed member side light emitting element 11a and the rotating member side light emitting element 11b are shared and configured with the same specifications. Further, the fixed member side light receiving element 12a and the rotating member side light receiving element 12b are shared and configured with the same specifications. In the rotary joint 1, the fixed member side light guide member 10a and the rotating member side light guide member 10b are made common, the fixed member side light emitting element 11a and the rotating member side light emitting element 11b are made common, and the fixed member side light receiving element. A configuration in which at least one of the common use of 12a and the rotating member side light receiving element 12b is made common may be used.

  In the rotary joint 1, a lens 31 a may be provided between the fixed member side light emitting element 11 a and the reflecting surface 14 a for preventing and converging signal light emitted from the fixed member side light emitting element 11 a. For example, as shown in FIG. 9, the lens surface 17 may be formed by raising the signal light incident surface 31a of the fixed member-side light guide member 10a in a convex shape.

  Similarly, a lens 33b is provided between the fixed member side light receiving element 12a and the reflecting surface 14b for preventing and converging the signal light received by the fixed member side light receiving element 12a, and the rotating member side light emitting element 11b. A lens 33c for preventing and converging the signal light emitted from the rotating member side light emitting element 11b is provided between the reflecting surface 14c and the rotating member side light receiving element 12b and the reflecting surface 14d. A lens 33d may be provided for preventing and converging the signal light received by the light receiving element 12b. The rotary joint 1 may be configured such that at least one of the lenses 33a, 33b, 33c, and 33d is provided.

  Further, in the rotary joint 1, at least one of the reflecting surfaces 14a, 14b, 14c, 14d of the light guide members 10a, 10b is a curved surface (concave surface) for preventing and converging signal light. Further, at least one of the signal light entrance / exit surfaces 13a and 13b of the light guide members 10a and 10b may be a curved surface (convex surface) for preventing and converging the signal light.

  Further, a lens shape or an inclined surface may be formed on the signal light entrance / exit surface 13a (13b) surface at the tip of the second light guide 35 to reduce the return light at the time of incident emission.

  Here, the light guide members 10a and 10b will be described in detail.

  The fixed member side light guide member 10 a is provided on the fixed member 3 side between the fixed member 3 and the rotary member 2, and the rotary member side light guide member 10 b is provided between the fixed member 3 and the rotary member 2. It is provided on the rotating member 2 side.

  Next, although the fixed member side light guide member 10a will be mainly described, the rotating member side light guide member 10b is also configured in the same manner.

  The fixing member side light guide member 10a is integrally formed of a resin material (other material such as glass) that transmits the signal light emitted from the light emitting elements 11a and 11b (for example, integrally formed by injection molding). Molded product). Further, in the fixed member side light guide member 10a, this ridge line portion (a convex corner portion where the surface of the fixed member side light guide member 10a is bent sharply) is on the flesh portion side of the fixed member side light guide member 10a. The angle is 45 ° or more. That is, the inferior angle of the intersecting angles in the two surfaces forming the ridge line portion of the fixed member side light guide member 10a is 45 ° or more in any ridge line portion, and all the ridge line portions are sharp. There is no point.

  As described above, the signal light (signal light emitted from the fixed member side light emitting element 11a) that has entered the light guide member 10a from a part of the outer surface (the signal light incident surface 31a) of the fixed member side light guide member 10a. ) Is reflected by the reflecting surface 14a formed by another part of the outer surface of the light guide member 10a (configured by the boundary), and the reflected signal light is further reflected on the other surface of the outer surface of the light guide member 10a. A part (signal light entrance / exit surface 13a) is configured to go out of the light guide member 10a.

  Further, the signal light (signal light emitted from the rotating member side light emitting element 11b) that has entered the light guide member 10a from a part of the outer surface (signal light input / output surface 13a) of the fixed member side light guide member 10a is guided. The reflected signal light is reflected by the reflecting surface 14b formed of the other part of the outer surface of the member 10a (configured at the boundary), and the reflected signal light is added to another part of the outer surface of the light guide member 10a (signal light). The light exits from the light exit surface 32a) to the outside of the light guide member 10a and is received by the fixed member side light receiving element 12a.

  The fixed member-side light guide member 10a includes a first light guide portion 34 formed in a columnar shape, a second light guide portion 35 formed in a columnar shape, and a recess 36 formed in a columnar shape. Is formed.

  The outer diameter of the second light guide 35 is smaller than that of the first light guide 34, and the second light guide 35 is coaxial with the first light guide 34 and has the first guide. It protrudes from one end face of the optical part 34 in the axial direction. The inner diameter of the recess 36 is smaller than the outer diameter of the first light guide 34 and larger than the outer diameter of the second light guide 35, and the recess 36 is an axis of the first light guide 34. And is recessed from the other end face in the axial direction of the first light guide portion 34 to the intermediate portion in the axial direction of the first light guide portion 34.

  A part of the surface of the concave portion 36 of the fixed member side light guide member 10a constitutes the reflective surface 14a, and another part of the surface of the concave portion 36 of the fixed member side light guide member 10a constitutes the reflective surface 14b. Yes. Similarly, a part of the surface of the concave portion 36 of the rotating member side light guide member 10b constitutes the reflecting surface 14c, and another part of the surface of the concave portion 36 of the rotating member side light guide member 10b is the reflecting surface 14d. Is configured.

  In addition, the fixed member side light guide member is arranged such that the axis of the first light guide part 34, the axis of the second light guide part 35, and the axis of the recess 36 coincide with the rotation center axis 4 of the rotary member 2. 10 a and the rotating member side light guide member 10 b are installed on the fixed member 3 and the rotating member 2.

  Further, in the fixed member-side light guide member 10a, the axial end surface of the first light guide 34 (the end surface on which the recess 36 is formed) is located on the fixed member 3 side, and the second light guide 35 is The fixing member 3 is integrally provided so as to be positioned on the rotating member 2 side. In the rotating member-side light guide member 10b, the end surface in the axial direction of the first light guide portion 34 (the end surface on which the concave portion 36 is formed) is located on the rotating member 2 side, and the second light guide portion 35 is a fixing member. The rotating member 2 is integrally provided so as to be positioned on the side 3.

  And the circular planar signal light entrance / exit surface 13a formed in the front-end | tip part of the 2nd light guide part 35 of the fixing member side light guide member 10a, and the 2nd light guide part of the rotation member side light guide member 10b. The circular flat signal light entrance / exit surface 13b formed at the front end portion of 35 is opposed to each other with a slight gap in the direction of the rotation center axis 4.

  Further, as shown in FIG. 13 and FIG. 14, the flesh portions of the light guide members 10 a and 10 b have a shape that does not have an extremely thin portion or an extremely thick portion.

  The reflective surface 14a (14c) and the reflective surface 14b (14d) are provided at the bottom (tip) of the concave portion 36 of the fixed member side light guide member 10a (rotating member side light guide member 10b).

  The reflection surface 14 a (14 c) is configured by a plane that obliquely intersects the axis 4 of the first light guide 34, and the reflection surface 14 b (14 d) is the axis 4 of the first light guide 34. And it is comprised by the plane which cross | intersects the plane which comprises the reflective surface 14a (14c) diagonally.

  A ridge line 37, which is a line segment at the intersection of the two planes, is inclined with respect to the axis 4 of each light guide 34, 35. For example, they intersect at an angle of 54.47 ° (90 ° -35.26 °) (intersect at one point and extend diagonally). The reflecting surface 14a (14c) and the reflecting surface 14b (14d) are symmetrical with respect to a plane defined by the axis 4 and the ridge line 37 (a plane including the rotation center axis 4 and the ridge line 37). Yes.

  Further, the intersection angle of the reflection surface 14b (14d) with respect to the reflection surface 14a (14c) (intersection angle at the recess 36; an angle obtained by subtracting the intersection angle at the flesh of the light guide members 10a and 10b from the angle of 360 °) is 180. It is smaller than °, for example, 90 °.

  The fixed member side light emitting element 11a and the fixed member side light receiving element 12a are provided in the middle part of the first light guide part 34 of the fixed member side light guide member 10a in the direction of the rotation center axis 4, and this first In the radial direction of one light guide portion 34, the light guide portion 34 is provided slightly apart from the first light guide portion 34.

  Similarly, the rotating member side light emitting element 11b and the rotating member side light receiving element 12b are provided in the middle part of the first light guide part 34 of the rotating member side light guide member 10b in the direction of the rotation center axis 4. In the radial direction of the first light guide portion 34, the first light guide portion 34 is provided slightly apart from the first light guide portion 34.

  Further, the rotary joint 1 is provided with a slip ring 41 for supplying electric power from the fixed member 3 to the rotating member 2 (see FIGS. 10 and 12). The slip ring 41 is provided outside the second light guide 35 in each light guide member 10a, 10b. That is, the ring-shaped sliding contact portion (conductive member) 23 of the slip ring 41 is arranged so that the second light guide portion 35 of each light guide member 10a, 10b is located inside with the rotation center axis 4 as the center. Is provided.

  The outer diameter of the second light guide portion 35 of each light guide member 10a, 10b is reduced, so that it is easy to secure a space for installing the slip ring 41, and the second guide The signal light passing through the optical unit 35 easily travels parallel to the axis 4 so that the signal light can be transmitted efficiently.

  The slip ring 41 will be described in more detail with reference to FIG.

  The rotary joint 1 shown in FIG. 10 includes a signal light transmission unit (a signal light transmission unit configured by the respective light guide members 10 a and 10 b) and a slip ring 41.

  The slip ring 41 includes a sliding contact part fixed side assembly 20 and a sliding contact part rotation side assembly 21. The sliding contact part fixed side assembly 20 includes a housing 42 and a substrate 24.

  The casing 42 includes a cylindrical member 43, a disk-shaped member 44 that blocks one opening of the cylindrical member 43, and a circle that blocks the other opening of the cylindrical member 43. A plate-like member 45 is provided. The casing 42 is provided at the center of the disk-shaped member 44, with the disk-shaped member 44 positioned on the fixed member 3 side and the disk-shaped member 45 positioned on the rotating member 2 side. The through hole fits into the second light guide 35 of the fixed member side light guide member 10a and is provided integrally with the fixed member side light guide member 10a.

  A disk-shaped substrate 24 is integrally provided inside the housing 42 and on the inner surface of the disk-shaped member 44. A plurality of ring-shaped conductive members (sliding contact portions) 23 are provided on one surface in the thickness direction of the substrate 24 (the surface opposite to the disk-shaped member 44) with the shaft 4 being concentric. ing. The diameters of the ring-shaped conductive members 23 are different from each other, and are separated from each other in the radial direction of the substrate 24.

  The sliding contact portion rotating side assembly 21 includes a brush holder 46 and a plurality of brushes (sliding contacts) 22. The brush holder 46 is located substantially inside the housing 42 and fits into the second light guide 35 of the rotating member side light guide member 10b so as to be provided integrally with the rotating member side light guide member 10b. It has been. Each brush 22 is in sliding contact with each of the circular conductive members 23 as the rotating member 2 rotates.

  Next, a slip ring 41a, which is a modification of the slip ring 41, will be described in detail with reference to FIG.

  The slip ring 41a shown in FIG. 12 is also provided with a sliding contact portion fixed side assembly 20a and a sliding contact portion rotation side assembly 21a. The sliding contact portion fixed side assembly 20a includes a housing 42a and a substrate 24a.

  The casing 42a includes a cylindrical member 43a, a disk-shaped member 44a blocking one opening of the cylindrical member 43a, and a circle blocking the other opening of the cylindrical member 43a. And a plate-like member 45a. The casing 42a is provided at the center of the disk-shaped member 44a, with the disk-shaped member 44a positioned on the fixed member 3 side and the disk-shaped member 45a positioned on the rotating member 2 side. The through hole fits into the second light guide 35 of the fixed member side light guide member 10a and is provided integrally with the fixed member side light guide member 10a.

  A substrate 24a is integrally provided inside the housing 42a and on the inner surface of the cylindrical member 43a. A plurality of brushes 23a are integrally provided on the substrate 24a. The brushes 23a are provided away from each other in the direction of the shaft 4.

  The sliding contact portion rotating side assembly 21a is configured to include a conductive member support 47 and a plurality of ring-shaped sliding contact portions 23b. The conductive member support 47 is formed in a cylindrical shape and is located substantially inside the housing 42, and fits into the second light guide portion 35 of the rotating member side light guide member 10b, so that the rotating member side light guide member 10b is integrally provided. Further, each ring-shaped sliding contact portion 23 b comes into sliding contact with each conductive member 23 a as the rotating member 2 rotates.

  As already understood, in the case of the rotary joint 1 using the surveillance camera 5, the video signal and the control signal are transmitted by the optical transmission, and the slip ring 41 is used to supply power to the rotating member 2 and to secure the ground line. Used.

  By the way, in the rotary joint 1, the directivity angle of each light emitting element 11a, 11b is about 18 °, and a PD (photodiode) having a size of 2 mm square is used as each light receiving element 12a, 12b.

  Further, as described above, the light emitting element 11a and the light receiving element 12a provided integrally with the rotating member 2 are disposed so as to form an angle of 90 ° with respect to the rotating shaft 4 when viewed from the direction of the rotating shaft 4. (See FIG. 14).

  Moreover, as shown in FIG. 3, each mirror surface finish is given to each reflective surface 14a, 14b, 14c, 14d of the light guide member 10a, 10b provided in the rotation part 2 side and the fixed part 3 side, The angles formed by the reflecting surfaces 14a, 14b, 14c, 14d and the shaft 4 are as shown in FIGS. That is, when the central axis 4 of the rotating member, the optical axis of the light emitting element 11a (11b), and the optical axis of the light receiving element 12a (12b) are orthogonal to each other, the plane orthogonal to the axis 4 The intersection angle with the ridgeline 37 is 35.26 °. 13A is a view of the light guide members 10a and 10b as viewed from the direction of the axis 4, and FIG. 13B is a view showing a cross section taken along the line BB in FIG. 13A. The BB cross section is a plane defined by the axis 4 and the optical axis of the light emitting element 11a. Moreover, FIG.13 (c) is a figure which shows CC cross section in Fig.13 (a). The CC cross section is a plane obtained by rotating the BB cross section in FIG. 13A by 45 ° clockwise around the axis 4. Moreover, FIG.14 (d) is a D arrow line view in Fig.13 (a), and FIG.14 (e) is a figure which shows the EE cross section in Fig.13 (a). The EE cross section is a surface obtained by rotating the CC cross section in FIG. 13A by 90 ° clockwise around the axis 4. FIG. 14F is a view as seen from the direction of arrow F in FIG.

  Further, as shown in FIG. 8, the signal light from the light emitting element 11a (11b) incident on the cylindrical reflecting portion (first light guiding portion) 34 of the light guiding member 10a (10b) is reflected by the reflecting portion (recessed portion). 36 is reflected by the reflecting surface 14a (14c) formed by a part of the bottom surface and guided to the light guide tube portion (second light guide portion 35). Conversely, light incident on the surface (reflecting surface 14a (14c)) facing the light emitting element 11a (11b) out of the signal light incident from the light guide tube end face 13a (13b) is incident on the light receiving element 12a (12b). Without reflection, the light is reflected in the direction of the light emitting element 11a (11b), but there is no problem.

  In the rotary joint 1, the reflecting surface 14 is a mirror-finished resin surface, but a reflecting film may be attached from the outside of the members (light guide members 10a and 10b).

  In the rotary joint 1 shown in FIG. 9, the holding portions 15 and 16 are integrally provided on the light guide member 10a (10b), and the light emitting element 11a (11b) and the light receiving element 12a (12b) are arranged with a positional accuracy of several hundred microns. It is directly held by the light guide member 10a (10b). In this way, by maintaining the position with high accuracy, the optical axis is stabilized and variation in optical transmission efficiency can be prevented. Furthermore, since the positional relationship between the light guide member 10a (10b) and the light emitting element 11a (11b) and the light receiving element 12a (12b) is accurately determined, as described above, the light guide member 10a (10b) has a reflective portion side surface. A lens shape is formed, and more optical signals can be incident on the light receiving element 12a (12b).

  As shown in FIG. 11, a D-cut through-hole having a shape obtained by cutting off a part of an arc of a circle is provided at the center of the casing 42 (42a), the brush holder 46, and the conductive member support 47. Correspondingly, the second light guide part 35 of the fixed member side light guide member 10a (10b) is also formed in a D-cut shape, and the housing 42 (42a), the brush holder 46, and the conductive member support 47 are formed. Is integrally provided on the light guide member 10a (10b).

  In place of the D-cut shape, the housing 42 (42a) and the brush are held by using an oval shape obtained by cutting an arc from a circle at two points, using a key and a key groove, or using a knurling. The body 46 and the conductive member support 47 may be provided integrally with the light guide member 10a (10b).

  Next, the metal mold | die 52 for shape | molding the light guide member 10a (10b) is demonstrated.

  15 is a cross-sectional view showing a schematic configuration of the mold 52, FIG. 15 (a) is a cross-sectional view when the mold 52 is cut along a plane including the shaft 4, and FIG. It is BB sectional drawing in Fig.15 (a).

  The mold 52 includes a lower mold 54 and an upper mold 55. The upper mold 55 is formed with recesses for forming the light guide portions 34 and 35 of the light guide member 10a (10b). The lower die 54 is integrally provided with a round bar 53 for forming the recess 36 of the light guide member 10a (10b).

  By the way, the installation angles (postures around the axis 4) of the light guide members 10a and 10b with respect to the light receiving elements 12a and 12b and the light emitting elements 11a and 11b mounted (integrally installed) on the fixed member 3 and the rotating member 2 are set. In order to decide, cylindrical projections 51 may be provided as shown in FIGS. 6, 7, and 15, but these projections 51 are formed on the reflective surface portion of the mold 52 as shown in FIGS. 7 and 15. Since the hole processing is performed on the same surface as the round bar 53 forming the (recess 36), if a D-shaped or the like anti-rotation shape is formed on the bottom of the round bar 53 (see FIG. 15B), the reflecting surface 14a. , 14b (14c, 14d) and the projection 51 are not misaligned, and it is easy to ensure the angle accuracy. Since the light guide members 34 and 35 are both cylindrical, they can be processed at a time, and a high degree of coaxiality can be easily obtained.

  Next, the operation of the rotary joint 1 will be described.

  As an initial state, it is assumed that electric power is supplied to the rotating member 2 by the slip ring 41 (41a).

  In this initial state, when a control signal or the like of the camera or the like is transmitted from the fixed member 3 side to the rotating member 2 side through the light guide members 10a and 10b under the control of a control device (not shown), the camera is Photograph a predetermined area. This image is converted into an optical signal and transmitted from the rotating member 2 side to the fixed member 3 via the light guide members 10a, 10b and the like.

  According to the rotary joint 1, since the fixed member side light receiving element 12a is provided at a position where the signal light emitted from the fixed member side light emitting element 11a cannot be received, one of the signal lights emitted from the fixed member side light emitting element 11a is provided. Even if the portion is not reflected by the first reflecting surface 14a of the fixed member side light guide member 10a, it is possible to avoid a situation in which the signal light not reflected is incident on the fixed member side light receiving element 12a. Therefore, it is possible to prevent the occurrence of crosstalk from the fixed member side light emitting element 11a to the fixed member side light receiving element 12a without separately providing a light shielding member (the signal light emitted from the fixed member side light emitting element 11a is fixed member side light receiving element). It is possible to prevent a situation in which the light is erroneously received at 12a). Similarly, occurrence of crosstalk from the rotating member side light emitting element 11b to the rotating member side light receiving element 12b can be prevented.

  Moreover, according to the rotary joint 1, the optical axis of the fixed member side light emitting element 11a and the optical axis of the fixed member side light receiving element 12a are substantially orthogonal. A general-purpose light-emitting element has a signal light irradiation angle of about 20 ° to 50 ° (for example, 36 °, which is twice a directivity angle of 18 °). It is about 50 °. Therefore, the fixed member side light receiving element 12a is provided at a position where the signal light emitted from the fixed member side light emitting element 11a cannot be received (see FIG. 17), and light emission for special use with a small irradiation angle and light receiving angle. Even without using an element or a light receiving element, it is possible to prevent the occurrence of crosstalk from the fixed member side light emitting element 11a to the fixed member side light receiving element 12a. Similarly, occurrence of crosstalk from the rotating member side light emitting element 11b to the rotating member side light receiving element 12b can be prevented.

  Further, according to the rotary joint 1, the rotation center axis 4, the optical axis of the fixed member side light emitting element 11a (11b), and the optical axis of the fixed member side light receiving element 12a (12b) are orthogonal to each other and intersect at almost one point. In addition, the rotation center axis 4, the optical axis of the light emitting element 11a (11b), and the optical axis of the light receiving element 12a (12b) are orthogonal to each other and intersect at almost one point. When assembling the fixed member side light emitting element 11a, the fixed member side light receiving element 12a, the rotating member side light guide member 10b, the rotating member side light emitting element 11b, and the rotating member side light receiving element 12b to the fixed member 3 or the rotating member 2, It becomes easy to make these positional accuracy accurate.

  Moreover, according to the rotary joint 1, the fixed member side light guide member 10a and the rotating member side light guide member 10b are configured with the same specifications, and the fixed member side light emitting element 11a and the rotating member side light emitting element 11b are the same. Since the fixed member side light receiving element 12a and the rotating member side light receiving element 12b are configured with the same specifications, the types of parts constituting the rotary joint 1 are reduced and the parts constituting the rotary joint are reduced. It is possible to realize a rotary joint that secures light isolation (separation) while reducing the productivity and cost by making common use.

  Further, according to the rotary joint 1, since the lenses 33a, 33b, 33c, and 33d for converging the signal light are provided, the signal light is prevented from being divergenced and the signal light can be transmitted efficiently. Furthermore, if each reflecting surface 14a, 14b, 14c, 14d is a concave surface for converging the signal light and the signal light entrance / exit surface 13a (13b) is a convex surface for converging the signal light, the divergence of the signal light is achieved. Is prevented, and signal light can be transmitted efficiently.

  Moreover, according to the rotary joint 1, since the light guide members 10a and 10b are formed of molded products including the reflecting surfaces 14a, 14b, 14c, and 14d, mass production becomes possible and an increase in price can be suppressed. it can.

  Further, according to the rotary joint 1, the minor angle of the intersection angles of the two surfaces forming the ridge line portion such as the ridge line 37 of the light guide members 10a and 10b is 45 ° or more in all the ridge line portions. Therefore, the acute angle portions in the light guide members 10a and 10b disappear, and if the ridge line portion is chamfered to a so-called thread surface, a mold suitable for mass production can be created. Therefore, a reduction in the area of the reflecting surfaces 14a, 14b, 14c, and 14d can be suppressed, the loss of off-axis rays can be reduced, and signal light can be transmitted efficiently.

  Further, according to the rotary joint 1, the light emitting elements 11a and 11b and the light receiving elements 12a and 12b are provided as described above, and the fixed member side light guide member 10a and the rotating member side light guide member 10b are provided. Since they are separated from each other, signal transmission is possible in a non-contact manner between the fixed member side light guide member 10a (fixed member 3) and the rotating member side light guide member 10b (rotating member 2).

  Moreover, according to the rotary joint 1, since there is no extreme difference in the thickness of the light guide members 10a and 10b, the sinking of the surface during molding can be prevented, and when the light guide members 10a and 10b are molded. The yield can be improved, and the manufacturing cost of the light guide members 10a and 10b can be reduced. In addition, since the acute angle portions in the light guide members 10a and 10b have disappeared and there is no extreme difference in the thickness of the flesh portions of the light guide members 10a and 10b, the flow of the resin before curing during molding is simply Thus, there is no complicated flow such as turbulent flow in the resin flow, the light guide members 10a and 10b are formed as a substantially homogeneous medium (signal light transmission medium), and the birefringence of the signal light in the light guide members 10a and 10b Occurrence can be prevented.

  Further, when the light guide members 10a and 10b are molded, if the lower mold 54 and the upper mold 55 as shown in FIG. 15 are used, an undercut does not occur and the configuration of the mold 52 can be simplified. In addition, high-precision molding can be easily performed. That is, if the first light guide portion 34 is formed in a cylindrical shape without providing a lens shape on the opposing surfaces of the light emitting elements 11a and 11b and the light receiving elements 12a and 12b, the gold mechanism is formed by a slide mechanism using an angular pin or the like. Since there is no need to provide a separate mold opening / closing part, a highly reliable and durable mold can be manufactured at low cost.

  Further, according to the rotary joint 1, the mold 52 used for forming the light guide members 10a and 10b has a shape based on a circle that is easy to machine, and particularly the reflective surfaces 14a, 14b, The portions 14c and 14d can be secured by simply forming an angle on the round bar 53 (see FIGS. 5 and 7), and the mold 52 is based on the cylindrical portion of the round bar 53. Therefore, it is possible to manufacture the mold 52 with high accuracy at low cost.

  That is, the reflecting portions (concave portions 36) constituting the light guide members 10a and 10b and the respective light guide portions 34 and 35 are substantially cylindrical, which can be easily performed by a general-purpose machine tool such as a lathe. Further, as shown in FIGS. 5 (a) and 5 (b), the reflecting portions 14a, 14b, 14c, and 14d only need to be cut at an angle of 45 ° or the like on the round bar, and the polished surface is polished. Also easy to do. Furthermore, since positioning based on the outer circumference of the round bar 53 is possible, it is easy to ensure accuracy. Further, as shown in FIG. 5 (c), since there is no acute angle part that is less than 45 °, a small chamfer of about 0.1 mm to about 0.2 mm called so-called thread chamfering along each ridge line (ridge line part). Since it can respond to shaping | molding if performed, in order to eliminate an acute angle part, the reflective surfaces 14a, 14b, 14c, and 14d do not reduce significantly.

  Further, according to the rotary joint 1, the first light guide portions 34 of the light guide members 10a and 10b are formed in a columnar shape (substantially cylindrical when the concave portion 36 is included), so that the light emitting elements 11a and 11b emit light. When the received signal light enters the first light guide 34, it is refracted and converged, and the loss of incidence on the light guide members 10a and 10b can be reduced.

  That is, as shown in FIG. 4, since the outer shapes of the light guide members 10a and 10b are circular, the spread of the signal light defined by the radiation angles (irradiation angles) of the light emitting elements 11a and 11b is changed to an R surface having a cylindrical outer diameter. Can be suppressed. As a result, more signal light can be incident on the reflecting surfaces 14a and 14c, and the loss of signal light reflected before entering the light guide members 10a and 10b can be suppressed to introduce more signal light. It can guide to the 1st light guide part 34 of optical members 10a and 10b. In addition, also when signal light is radiate | emitted from the light guide members 10a and 10b to the light receiving elements 12a and 12b, the situation where signal light spreads similarly can be suppressed.

  Incidentally, as shown in FIG. 16, the outer shape of the first light guide portion 34 of the light guide members 10a and 10b may be formed in an arc shape in the direction of the rotation center axis 4 such as a spherical shape. Thereby, the situation where signal light spreads can be controlled more efficiently.

  Further, as already understood, the optical axes of the light emitting elements 11a and 11b may be inclined with respect to the rotation center axis 4 (see FIG. 18), and similarly, the optical axes of the light receiving elements 12a and 12b. May be inclined obliquely with respect to the rotation center axis 4.

  Further, as shown in FIG. 19, the axes of the light guide members 10 a and 10 b may be inclined with respect to the rotation center axis 4. In the case of the configuration shown in FIGS. 18 and 19, the angle of the reflecting surface 14 is also changed as appropriate.

  As shown in FIG. 19, by tilting the shaft 4a of the light guide members 10a and 10b obliquely with respect to the rotation center shaft 4, the shaft 4a and the signal light entrance / exit surface 13a (13b) are not orthogonally crossed. Crosstalk due to return light at the time of incident and emission in each light guide member can be suppressed.

  Moreover, you may change suitably the form of the light guide members 10a and 10b. For example, the outer diameter of the first light guide 34 and the outer diameter of the second light guide 35 may be equal to each other, or the first light guide 34 and the second light guide 35 may be The shaft may be bent.

DESCRIPTION OF SYMBOLS 1 Rotary joint 2 Rotating member 3 Fixed member 4 Rotation center axis 10a Fixed member side light guide member 10b Rotating member side light guide member 11a Fixed member side light emitting element 11b Rotating member side light emitting element 12a Fixed member side light receiving element 12b Rotating member side light receiving Element 14 (14a, 14b, 14c, 14d) Reflective surface 17 Lens surface 33a, 33b, 33c, 33d Lens 34 First light guide 35 Second light guide 41, 41a Slip ring

Claims (7)

A fixing member;
A rotating member rotatably provided on the fixed member with a predetermined axis as a rotation center;
A fixing member-side light guide member provided on the fixing member, the first reflecting surface and the second reflecting surface;
A rotating member-side light guide member that includes a third reflecting surface and a fourth reflecting surface, and is provided on the rotating member;
A fixing member side light emitting element provided on the fixing member or the fixing member side light guide member;
A fixing member side light receiving element provided on the fixing member or the fixing member side light guide member at a position where the signal light emitted from the fixing member side light emitting element cannot be received;
A rotating member-side light emitting element provided on the rotating member or the rotating member-side light guide member;
A rotating member side light receiving element provided on the rotating member or the rotating member side light guide member at a position where the signal light emitted from the rotating member side light emitting element cannot be received;
The signal light emitted from the fixing member side light emitting element is reflected by the first reflecting surface of the fixing member side light guide member and reflected by the fourth reflecting surface of the rotating member side light guide member. Received by the rotating member side light receiving element,
The signal light emitted by the rotating member-side light emitting element is reflected by the third reflecting surface of the rotating member-side light guide member and reflected by the second reflecting surface of the fixing member-side light guide member. A rotary joint configured to be received by a side light receiving element. A fixing member;
A rotating member rotatably provided on the fixed member with a predetermined axis as a rotation center;
A fixing member-side light guide member provided on the fixing member, the first reflecting surface and the second reflecting surface;
A rotating member-side light guide member that includes a third reflecting surface and a fourth reflecting surface, and is provided on the rotating member;
A fixing member-side light emitting element provided on the fixing member or the fixing member-side light guide member such that an optical axis intersects the rotation center axis;
A fixed member-side light receiving element provided on the fixed member or the fixed member-side light guide member so that an optical axis intersects the rotation axis and the optical axis of the fixed member-side light-emitting element;
A rotating member-side light emitting element provided on the rotating member or the rotating member-side light guide member such that an optical axis intersects the rotation center axis;
A rotating member-side light receiving element provided on the rotating member or the rotating member-side light guide member such that an optical axis intersects with the rotation center axis and the optical axis of the rotating member-side light emitting element;
The signal light emitted from the fixing member side light emitting element is reflected by the first reflecting surface of the fixing member side light guide member and reflected by the fourth reflecting surface of the rotating member side light guide member. Received by the rotating member side light receiving element,
The signal light emitted by the rotating member-side light emitting element is reflected by the third reflecting surface of the rotating member-side light guide member and reflected by the second reflecting surface of the fixing member-side light guide member. A rotary joint configured to be received by a side light receiving element. In the rotary joint according to claim 1 or 2,
The fixed member side light guide member and the rotating member side light guide member are configured with the same specifications as each other,
The fixed member side light emitting element and the rotating member side light emitting element are configured with the same specifications as each other,
Whether the fixed member side light receiving element and the rotating member side light receiving element are configured with the same specifications,
A rotary joint characterized by being in at least one of the embodiments. In the rotary joint according to any one of claims 1 to 3,
A first lens for converging the signal light emitted by the fixing member side light emitting element between the fixing member side light emitting element and the first reflecting surface;
A second lens for converging signal light received by the stationary member side light receiving element between the stationary member side light receiving element and the second reflecting surface;
A third lens for converging the signal light emitted by the rotating member side light emitting element between the rotating member side light emitting element and the third reflecting surface;
A fourth lens for converging the signal light received by the rotating member side light receiving element between the rotating member side light receiving element and the fourth reflecting surface;
A rotary joint provided with at least one of the lenses. In the rotary joint according to any one of claims 1 to 4,
The light guide member is a molded product integrally formed of a material that transmits signal light,
The signal light that has entered the light guide member from a part of the outer surface of the light guide member is reflected by the reflection surface that is configured by another part of the outer surface of the light guide member, and the reflected signal The light is configured to go out of the light guide member from still another part of the outer surface of the light guide member,
A rotary joint characterized in that an inferior angle of crossing angles at two surfaces forming a ridge line portion of the light guide member is 45 ° or more in all ridge line portions of the light guide member. In the rotary joint according to any one of claims 1 to 5,
A rotary joint having a slip ring for supplying electric power from the fixed member to the rotating member. In a light guide member used when transmitting an optical signal between a fixed member and a rotating member provided rotatably on the fixed member with a predetermined axis as a rotation center,
A first light guide formed in a columnar shape;
It is formed in a cylindrical shape having an outer diameter smaller than that of the first light guide, and is coaxial with the axis of the first light guide and protrudes from one end surface in the axial direction of the first light guide. A second light guide;
An inner diameter is smaller than the outer diameter of the first light guide and is larger than the outer diameter of the second light guide, and is formed coaxially with the axis of the first light guide. A recess recessed from the other end face in the axial direction of one light guide portion to an intermediate portion in the axial direction of the first light guide portion;
A planar first reflecting surface provided at the bottom of the recess and obliquely intersecting the axis of each light guide;
A planar second reflecting surface provided at the bottom of the recess and obliquely intersecting the axis of each light guide and the first reflecting surface;
A light guide member characterized by comprising:

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