Anti-vibration unit for optical communication device, optical communication device, and optical space communication system

Abstract

To provide a technique capable of eliminating the deviation of an optical axis so as to be able to realize stable optical space communication in optical space communication.SOLUTION: An optical space communication system (1) includes a transmitting device (2) and a receiving device (3), both of which have a vibration-proof unit (6). The vibration-proof unit (6) includes first and second correction lens groups and a controller (20). The controller (20) identifies changes in the orientation and position of each of the transmitting device (2) and the receiving device (3) without referring to signal light, and controls the first and second correction lens groups based on the changes to correct the tilt of an optical axis (OA) of the signal light.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an anti-vibration unit for an optical communication device, an optical communication device, and an optical free space communication system. [Background technology]

[0002] As a communication device between two distant points, an optical space communication system is known in which the devices are installed facing each other and communicate by sending optical signals by optical beams propagating in free space. The optical communication device constituting the system as the transmitting side or the receiving side in the optical space communication system may be subjected to various vibrations depending on the installation state. In the optical space communication system, these vibrations may cause a state in which the signal light does not reach the designated receiving device sufficiently.

[0003] As a technique for solving this problem, a technique is known in which, in an optical communication device, deviation of the optical axis caused by vibration of the device is corrected based on the detection result of the position of the received signal light (see, for example, Patent Document 1).

[0004] Furthermore, as a technique for correcting the axis of a light beam, a technique is known in which a wedge prism is used to correct the tilt of the visual axis due to vibration in an imaging device (see, for example, Patent Document 2).

[0005] Furthermore, a known technique for correcting the axis of a light beam is a mechanism that rotates a pair of wedge prisms to correct deviation of the optical axis caused by shaking of an imaging device such as a camera (see, for example, Patent Document 3).

[0006] Also, a technique is known in which two pairs of rotationally driven wedge prisms are combined to correct misalignment of the optical axis in an optical communication device (see, for example, Patent Document 4). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2004-15135 A [Patent Document 2] JP 2012-197010 A [Patent Document 3] JP 2012-137734 A [Patent Document 4] JP 2016-164548 A Summary of the Invention [Problem to be solved by the invention]

[0008] However, the above-mentioned conventional technology has a problem that the load of information processing for controlling the tilt of the optical axis is large. For example, in the technology described in Patent Document 1, the optical axis of the signal light is corrected using a light receiving element in the receiving device. This correction method cannot be applied to the transmitting side, and control delays are likely to occur because communication processing and vibration prevention processing are performed simultaneously. For this reason, correction of the optical axis becomes insufficient, especially when the optical communication device vibrates due to high-frequency vibration, and the stability of the optical communication may become insufficient.

[0009] An object of one aspect of the present invention is to provide a technique capable of eliminating misalignment of an optical axis in optical space communication so as to realize stable optical space communication. [Means for solving the problem]

[0010] In order to solve the above problems, an anti-vibration unit for an optical communication device according to one embodiment of the present invention has a group of anti-vibration lenses and a controller that determines a change in orientation or position of the optical communication device without referring to the signal light output from or input to the optical communication device, and corrects the tilt of the optical axis of the signal light by controlling the anti-vibration lens group based on the determined change in orientation or position.

[0011] In order to solve the above problem, an optical communication device according to an aspect of the present invention includes the above-mentioned vibration isolation unit for an optical communication device.

[0012] In addition, in order to solve the above problem, an optical space communication system according to one embodiment of the present invention includes a transmitting device and a receiving device, and one or both of the transmitting device and the receiving device are equipped with the above-mentioned vibration isolation unit for an optical communication device. Effect of the Invention

[0013] According to one aspect of the present invention, it is possible to realize a technique capable of eliminating misalignment of an optical axis in optical space communication so as to realize stable optical space communication. [Brief description of the drawings]

[0014] [Figure 1] 1 is a diagram illustrating a schematic configuration of an optical free space communication system according to an embodiment of the present invention. [Diagram 2] 1 is a diagram illustrating a schematic functional configuration of an optical space communication system according to an embodiment of the present invention. [Diagram 3] 2 is a cross-sectional view showing a schematic structure of an optical axis adjusting unit according to an embodiment of the present invention; FIG. [Figure 4] FIG. 2 is a diagram illustrating a schematic configuration of a wedge prism unit according to an embodiment of the present invention. [Diagram 5] 5A and 5B are diagrams for explaining the rotational drive of a wedge prism unit in one embodiment of the present invention. [Figure 6] FIG. 2 is a circuit block diagram of an image stabilization unit according to an embodiment of the present invention. [Figure 7] 5A and 5B are diagrams for explaining adjustment of an optical axis by a first correction lens group and a second correction lens group in one embodiment of the present invention. [Figure 8] 5A and 5B are diagrams illustrating a relationship between the amount of rotational drive by the first correction lens group and the second correction lens group and the amount of correction of the optical axis in one embodiment of the present invention. [Figure 9] 5A and 5B are diagrams for explaining the tilt of the optical axis due to rotational shaking of the transmitting device or the receiving device in one embodiment of the present invention. [Figure 10]4A and 4B are diagrams for explaining the tilt of the optical axis due to shift fluctuation of the transmitting device or the receiving device in one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] In the present invention, the vibration of the optical communication device itself is detected, and the vibration-proof lens group is quickly controlled independently of the optical communication control so as to offset the vibration, thereby stabilizing the communication state in the optical space communication. Hereinafter, an embodiment of the present invention will be described.

[0016] Fig. 1 is a diagram showing a schematic configuration of an optical free space communication system according to an embodiment of the present invention. As shown in Fig. 1, the optical free space communication system 1 has a transmitting device 2 and a receiving device 3. The transmitting device 2 and the receiving device 3 are each mounted on a pan head 4. The transmitting device 2 and the receiving device 3 each correspond to an optical communication device.

[0017] The transmitting device 2 has a laser transmitting circuit 5 and an anti-shake unit 6, in this order from the light source side. The receiving device 3 has a anti-shake unit 6 and a laser receiving circuit 7, in this order from the light source side. The receiving device 3 has a laser receiving circuit 7 instead of the laser transmitting circuit 5, and is configured similarly to the transmitting device 2. The anti-shake unit 6, which will be described in detail later, is a unit that can adjust the direction of the optical axis of the laser light passing through the anti-shake unit 6.

[0018] FIG. 2 is a diagram showing a schematic functional configuration of an optical space communication system according to an embodiment of the present invention. As shown in FIG. 2, the vibration isolation unit 6 has an optical axis adjustment unit 10, a controller 20, and a sensor unit 30. The optical axis adjustment unit 10 has a first correction lens group 11, a second correction lens group 12, and position sensors 13 to 16. The first correction lens group 11 and the second correction lens group 12 correspond to vibration isolation lenses. The position sensors 13 and 14 are sensors for detecting the positions of wedge prisms P1 and P2 (described later) in the first correction lens group 11 in the respective rotational directions. Similarly, the position sensors 15 and 16 are sensors for detecting the positions of wedge prisms P4 and P3 (described later) in the second correction lens group 12 in the respective rotational directions.

[0019] The position sensors 15, 16 can be composed of, for example, a Hall element and a magnet arranged corresponding to the Hall element. The Hall element is fixed, for example, on the wedge prism side (for example, on a frame plate described below), and the magnet is fixed, for example, at a position facing the Hall element. The Hall element outputs a Hall output (V) proportional to the strength of the magnetic field generated by the magnet due to the "Hall effect." Since the Hall output and the amount of movement of the Hall element (the rotation angle of the wedge prism) are linearly related, it is possible to easily determine the position of the wedge prism in the rotational direction by detecting the Hall output.

[0020] The controller 20 identifies the inclination of the transmitting device 2 or the receiving device 3 by referring to the signal of the sensor unit 30, calculates the driving amount of the optical axis adjustment unit 10 based on the identified inclination, and outputs a signal according to the driving amount. The controller 20 is configured, for example, as an integrated circuit including an input unit, a calculation unit, a control unit, a storage unit, and an output unit. The controller 20 is configured to receive signals from the position sensors 13-16 and the sensor unit 30, and output signals to the first correction lens group 11 and the second correction lens group 12.

[0021] The sensor unit 30 has a sensor that detects the inclination of the transmitting device 2 or the receiving device 3. For example, the sensor unit 30 includes a gyro sensor and an acceleration sensor.

[0022] 3 is a cross-sectional view showing a schematic structure of the optical axis adjustment unit 10 according to the embodiment of the present invention. As shown in FIG. 3, the optical axis adjustment unit 10 has a substrate 101, a cover 102, a pin 103, a magnet 104, a first correction lens group 11, and a second correction lens group 12.

[0023] The substrate 101 is a plate member having a planar shape of an annular ring. The cover 102 has a cylindrical peripheral wall and a planar shape of an annular top plate, and is fixed to the substrate 101 to form a cylindrical chamber. There are two pins 103, each of which extends from the top plate of the cover 102 into the chamber. The magnets 104 are intermittently arranged in the axial direction in the cylindrical chamber formed by the substrate 101 and the cover 102. For example, the magnets 104 are arranged on the inner surface of the substrate 101, in the axial middle portion of the peripheral wall of the cover 102, and on the inner surface of the top plate of the cover 102.

[0024] Each of the first and second correction lens groups 11 and 12 includes a pair of wedge prism units. Thus, this embodiment includes two pairs of wedge prisms as vibration-proof lens groups. The first correction lens group 11 includes wedge prism units 110 and 210, and the second correction lens group 12 includes wedge prism units 120 and 220. Each of the wedge prism units 110, 210, 120, and 220 is supported in the room by a pin 103.

[0025] 4 is a diagram showing a schematic configuration of a wedge prism unit in the embodiment of the present invention. Since the wedge prism units 110, 210, 120, and 220 all have the same configuration, only the configuration of the wedge prism unit 110 will be described.

[0026] As shown in Figure 4, the wedge prism unit 110 has a frame plate 111 having a circular planar shape, a slit 112 formed in the frame plate 111 along a central opening, a coil 113 disposed on the frame plate 111, and a wedge prism P1 fixed to the central opening of the frame plate 111.

[0027] Two slits 112 are formed at positions facing each other with the wedge prism P1 in between. Each slit 112 has a substantially arc-shaped opening that curves along the arc of the planar shape of the frame plate 111.

[0028] Coil 113 is disposed at a position equidistant from each of the two slits 112 and in a direction parallel to a tangent to the circumference of frame plate 111. Coil 113 is connected to a power source (not shown) so that it can be electrically connected and the direction of electrical current can be switched.

[0029] The wedge prism unit 110 is supported rotatably from the side in the room of the optical axis adjustment unit 10 by inserting the pin 103 into the slit 112. In this way, in this embodiment, the wedge prism unit 110 adopts a structure in which the pin 103 fixed to the cover 102 passes through the slit 112 of the wedge prism unit 110 to support the wedge prism unit 110. The coil 113 of the wedge prism unit 110 supported by the pin 103 faces one of the magnets 104 of the optical axis adjustment unit 10. In this way, this embodiment includes the frame plate 111 which is a movable frame that holds the wedge prism P1, the cover 102 which rotatably supports the frame plate 111, and the coil 113 provided on the plate frame. Two arc-shaped slits 112 are formed in the frame plate 111, and the cover 102 has two pins 103 which pass through the two slits 112, respectively.

[0030] FIG. 5 is a diagram for explaining the rotational drive of the wedge prism unit in the embodiment of the present invention. A magnetic pole is generated in the coil 113 by energizing the coil 113. Depending on the magnetic pole generated in the coil 113, an attractive force or a repulsive force is generated between the coil 113 and the magnet 104 facing the coil 113. Depending on the attractive force or the repulsive force generated, a force is generated in the frame plate 111 along its circumferential direction. Depending on the generated force, the slit 112 slides against the pin 103, and the frame plate 111 moves to a position depending on the force. Therefore, the wedge prism P1 is driven to rotate in the direction of the arrow A1. In this way, in this embodiment, the frame plate 111 is rotated relative to the cover 102 by the magnetic force generated by the coil 113.

[0031] In this embodiment, as described above, wedge prism unit 110 has wedge prism P1 and coil 113 for driving the unit to rotate. Meanwhile, wedge prism unit 110 is supported by pin 103 inserted into slit 112. For this reason, in wedge prism unit 110, the force generated by coil 113 for supporting its own weight can be reduced, and therefore the weight of coil 113 can be reduced.

[0032] Furthermore, because the wedge prism unit 110 is supported laterally by the pins 103, the wedge prism unit 110 is supported by the pins 103 even when no current is applied to the coil 113. Therefore, a mechanism for preventing the unit from falling when no current is applied is not required, and in this embodiment, a reduction in weight is achieved by not including such a mechanism.

[0033] Furthermore, the wedge prism unit 110 supported as described above allows the optical axis to be corrected by rotational drive, and the correction angle can be made wide.

[0034] Furthermore, since it is possible to reduce the weight of the coil 113, which can be considered a driving unit, it is possible to reduce the inertial force in the rotational drive of the wedge prism unit 110. Therefore, the above-mentioned support form of the wedge prism unit 110 makes it possible to realize high-speed frequency drive that can handle high-frequency vibrations specific to optical communication devices. From this perspective, too, the present embodiment in which the wedge prism unit 110 is supported by the pin 103 can be said to be suitable for correcting the tilt of the optical axis in an optical communication device.

[0035] The amount of rotational drive of the wedge prism unit is determined as follows: Figure 6 is a circuit block diagram of the image stabilization unit in the embodiment of the present invention.

[0036] The gyro sensor of the sensor unit 30 detects the inclination of the transmission device 2. The acceleration sensor of the sensor unit 30 detects vertical vibrations of the transmission device 2. The sensor unit 30 transmits signals of the detection results of these sensors to the controller 20.

[0037] The controller 20 calculates the rotation angle (Act rotation angle) of each wedge prism unit that adjusts the optical axis OA toward the receiving device 3 to an appropriate inclination based on the signal from the sensor unit 30. In this way, the controller 20 identifies changes in the orientation and position of the optical communication devices (the transmitting device 2 and the receiving device 3) in the optical space communication system 1 by referring to the output signals of the gyro sensor and the acceleration sensor.

[0038] For example, the rotation angle of each wedge prism unit can be calculated based on the shift vibration amount and rotation vibration amount of the optical communication device. The shift vibration amount and rotation vibration amount can be obtained by appropriately adjusting and adding up the detection signal of the acceleration sensor and the detection signal of the gyro sensor. The detection signal can be appropriately adjusted by extracting, amplifying, removing, time-integrating, or multiplying by an appropriate gain various components of the movement of the optical communication device contained in the detection signal.

[0039] The controller 20 generates and outputs a signal indicating the interval for turning on and off the current to the coil 113 of each wedge prism unit based on the calculated value of the Act rotation angle. By turning on and off the current to the coil 113 according to the signal, each wedge prism unit is rotated to a position of the desired rotation angle.

[0040] The position sensor of the optical axis adjustment unit 10 detects the position of the wedge prism unit in the rotation direction. The optical axis adjustment unit 10 transmits a signal of the detection result of the position sensor to the controller 20. Based on the signal from the optical axis adjustment unit 10, the controller 20 performs feedback control of the position of each wedge prism unit in the rotation direction.

[0041] Thus, in this embodiment, the controller 20 identifies the change in the orientation or position of the optical communication device without referring to the signal light output from or input to the optical communication device. Then, the controller 20 corrects the tilt of the optical axis OA of the signal light by controlling the first correction lens group 11 and the second correction lens group 12 based on the identified change in orientation or position. More specifically, in this embodiment, the controller 20 calculates the rotation angle of the wedge prism from the output values ​​of various sensors, and rotates the wedge prism by performing PWM control on the coil 113. Then, for example, the rotation position of the coil 113 is returned to the controller 20 by a position sensor, and feedback processing of the control of the rotation drive of the wedge prism is performed.

[0042] The optical axis is adjusted by the rotational drive of the wedge prism unit as follows. Fig. 7 is a diagram for explaining the adjustment of the optical axis by the first correction lens group and the second correction lens group in this embodiment. Fig. 8 is a diagram showing a schematic diagram of the relationship between the amount of rotational drive by the first correction lens group and the second correction lens group in this embodiment and the correction amount of the optical axis.

[0043] In the optical axis adjustment unit 10, the first correction lens group 11 and the second correction lens group 12 adjust the optical axis to tilt in directions intersecting each other on a plane perpendicular to the optical axis. For example, the first correction lens group 11 adjusts the tilt of the optical axis in the vertical direction (e.g., the direction of arrow A11), and the second correction lens group 12 adjusts the tilt of the optical axis in the horizontal direction (e.g., the direction of arrow A12).

[0044] In the first correction lens group 11, each of the pair of wedge prisms is driven to rotate independently. The magnitude of the tilt of the optical axis in the vertical direction (up and down direction) in the first correction lens group 11 shows a substantially linear correlation with the magnitude of the rotational drive of the wedge prism. Similarly, in the second correction lens group 12, each of the pair of wedge prisms is driven to rotate independently. The magnitude of the tilt of the optical axis in the horizontal direction (left and right direction) in the second correction lens group 12 shows a substantially linear correlation with the magnitude of the rotational drive of the wedge prism. In this way, in a correction lens group having a pair of wedge prisms, it is possible to linearly approximate the amount of rotation of the wedge prism and the deflection of the optical axis, and it is also possible to increase the correction angle.

[0045] In this embodiment, a total of four wedge prisms are used, two for the upper and lower correction lens groups and two for the left and right correction lens groups. The rotation amount of these wedge prisms can be adjusted, for example, by the position of the apex angle of each wedge prism. This adjustment makes it possible to calculate the rotation amount using a linear approximation formula as described above, eliminating the need for nonlinear state correction. Therefore, it is possible to reduce the calculation load related to the control of the tilt of the optical axis. This enables high-speed control calculation, shortens the control period, and improves control ability.

[0046] Here, the behavior of an optical communication device that causes tilt of the optical axis will be described. Fig. 9 is a diagram for explaining the tilt of the optical axis caused by the rotational vibration of the transmitting device or the receiving device in this embodiment. Fig. 10 is a diagram for explaining the tilt of the optical axis caused by the shift vibration of the transmitting device or the receiving device in this embodiment.

[0047] In the location where the optical communication device is installed, there may be a mixture of vibrations with low frequency and large amplitude and vibrations with high frequency and small amplitude. For example, as shown in Fig. 9, the vibration form of the optical communication device may be a rotational vibration caused by the transmitting device or receiving device rotating as indicated by the arrow S with an arbitrary location as the center of rotation. In addition, as shown in Fig. 10, the vibration form may be a rotational vibration caused by the transmitting device or receiving device rotating as indicated by the arrow S with an arbitrary location as the center of rotation. 0 There is a shift vibration that moves in the vertical direction relative to the optical axis. The magnitude of the rotational vibration can be detected by a gyro sensor, and the magnitude of the shift vibration can be detected by an acceleration sensor. Taking into account the frequency range of the vibration that can be handled and the type of vibration, the vibration isolation for optical communication devices is required to be able to handle vibrations with a frequency of 1 to 100 Hz and a correctable angle (correction angle) of the optical axis of about 5°.

[0048] The tilt of the optical axis can be easily expressed by the distance in each of two directions perpendicular to the optical axis. The tilt of the optical axis by the optical axis adjustment unit 10 can be easily replaced with the amount of rotation of the wedge prism. Therefore, in this embodiment, the adjustment amount of the tilt of the optical axis can be quickly determined. And the rotational drive of the wedge prism can be quickly achieved. Therefore, in this embodiment, it is possible to quickly achieve control of the tilt of the optical axis according to the vibration of the optical axis.

[0049] Here, the vibration reduction technology that has been used in lenses for image stabilization and the like has a narrow frequency range (e.g., about 1 to 20 Hz) and a clearly small correction angle (e.g., less than 0.5°) compared to the vibrations in optical communication devices. For this reason, even if it is applied to vibration reduction in optical communication devices, it is not necessarily possible to obtain a sufficient effect.

[0050] Furthermore, when correcting the optical axis based on the light received by the laser receiving circuit, the load on the information processing for calculating the amount of optical axis correction and the amount of drive of the correction lens is large, making it difficult to correct the tilt of the optical axis in response to high-frequency vibrations in the optical communication device.

[0051] For example, the prior art described in Patent Document 1 has the same framework of vibration isolation for signal light in an optical communication device. However, the above prior art achieves vibration isolation by different methods depending on whether the vibration is small or large. That is, when the vibration is small, a mirror is used for vibration isolation in part of the internal optical system in the optical communication device. When the vibration is large, vibration isolation is achieved by moving the optical system itself using a camera platform or the like. In either case, vibration detection is performed by a receiving device (image sensor) in the optical communication device. In contrast, in the embodiment of the present invention, vibration isolation of the optical axis is achieved by part of the optical system of the optical communication device, regardless of the magnitude of the vibration. In addition, a dedicated sensor is used to detect vibration, and the vibration of the optical communication device itself is detected.

[0052] Moreover, the prior art described in Patent Document 2 is an anti-shake technology for an imaging device, and is not an anti-shake technology for signal light in optical space communication. The embodiment of the present invention uses a wedge prism as an anti-shake lens for signal light in the optical system of an optical communication device, and is a system that anti-shakes not a captured image but the signal light as communication data. The embodiment of the present invention also differs greatly in its usage environment from the prior art described in Patent Document 2. In this embodiment, an anti-shake function against vibrations of an optical communication device that is usually fixed and installed outdoors is realized. In addition, in this embodiment, a combination of a gyro sensor and an acceleration sensor can be used to detect vibrations of the optical communication device, and as a result, it is possible to detect with higher accuracy.

[0053] In this embodiment, the vibration of the optical communication device itself is acquired with high accuracy by various sensors, analyzed, and a correction lens with a large correction angle is controlled. In this embodiment, the tilt of the optical axis in optical communication can be corrected according to the vibration of the optical communication device, independent of the communication function of the optical space communication system. Therefore, the vibration isolation unit for optical communication devices in this embodiment can be additionally installed on existing optical communication devices.

[0054] In this embodiment, the wedge prism operating mechanism (actuator) is a suitable mechanism that corresponds to the frequency characteristics of vibrations in optical communication devices. The actuator enables correction of the optical axis by a rotational motion with a small inertial force. A wedge prism is used to correct the optical axis, and a wide range of correction angles can be achieved by the rotational drive.

[0055] In addition, this embodiment is configured to perform optical axis correction independently of control for optical space communication by referring to the detection value of a sensor that detects vibration of the optical communication device. Therefore, it is possible to analyze in detail the vibration occurring at the installation location of the optical communication device, and it is possible to perform more accurate optical axis correction in optical space communication compared to the conventional technology that corrects the optical axis by analyzing the communication signal of optical space communication.

[0056] In addition, since this embodiment can correct the optical axis without interfering with the optical space communication in the optical space communication system, it can be newly added to an existing optical communication device. In this way, according to this embodiment, it is possible to add a high-precision optical axis correction function to an existing optical communication device by retrofitting it. In addition, since it can be retrofitted without interfering with the optical space communication, it can be incorporated into both the transmitting and receiving devices in the optical space communication, making it possible to correct the optical axis with even higher precision.

[0057] Therefore, this embodiment is suitable for correcting vibration blur of a laser beam in an optical space communication system in which the blinking of a laser beam is used as a signal to transmit information between a pair of devices by its directionality in space.

[0058] [Modifications] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in the different embodiments are also included in the technical scope of the present invention.

[0059] For example, the control block of the controller 20 can be realized by a logic circuit (hardware) formed on an integrated circuit (IC chip) or the like, but may also be realized by software.

[0060] In the latter case, the controller 20 includes a computer that executes instructions of a program, which is software that realizes each function. The computer includes, for example, one or more processors, and a computer-readable recording medium that stores the program. The object of the present invention is achieved by having the processor read and execute the program from the recording medium in the computer.

[0061] The processor may be, for example, a CPU (Central Processing Unit). The recording medium may be a "non-transitory tangible medium" such as a ROM (Read Only Memory), as well as a tape, a disk, a card, a semiconductor memory, a programmable logic circuit, etc. The device may further include a RAM (Random Access Memory) for expanding the program.

[0062] The program may be supplied to the computer via any transmission medium capable of transmitting the program (such as a communication network or a broadcast wave). Note that one aspect of the present invention may also be realized in the form of a data signal embedded in a carrier wave, in which the program is embodied by electronic transmission.

[0063] In the above-mentioned embodiment, the sensor unit 30 includes a gyro sensor and an acceleration sensor. However, in the present invention, the type of sensor constituting the sensor unit is not limited as long as the sensor can obtain a detection value capable of identifying at least one of the changes in the orientation or position of the optical communication device. Examples of sensors that can be used in the embodiment of the present invention other than the above-mentioned gyro sensor and acceleration sensor include an inclination angle sensor. The inclination angle sensor can detect the inclination of the installation location (optical communication device) with high accuracy. By using such an inclination angle sensor, it is possible to control the rotation amount of the wedge prism based on the detection result of the sensor, and it is possible to appropriately correct the inclination of the optical axis. In addition, when the type and magnitude of vibration of the optical communication device are specified, only a sensor corresponding to the vibration may be used (for example, only a gyro sensor if only the orientation of the optical communication device is required, or only an acceleration sensor if only the position of the optical communication device is required).

[0064] In addition, in the present invention, the vibration-proof lens group is not limited to two pairs of wedge prisms, and may be other optical elements capable of adjusting the tilt of the optical axis of the light output in the optical space communication. The number of wedge prisms can be appropriately determined according to the application of the vibration-proof unit in the embodiment of the present invention. When two pairs (four pieces) of wedge prisms are used as in the above-mentioned embodiment, it is possible to control the tilt of the optical axis with high precision, but depending on the installation situation of the optical communication device, such as when the generated vibration is limited, only one wedge prism may be used.

[0065] In the above-mentioned embodiment, the correction of the optical axis by the anti-vibration lens group is realized by rotating the wedge prism. However, in the present invention, the operation mode of the anti-vibration lens group for correcting the optical axis can be appropriately determined according to the anti-vibration lens group to be adopted. In the embodiment of the present invention, for example, the optical axis correction by lens shift used in single-lens reflex lenses, as described in JP 2013-178429 A, may be adopted. According to such an optical axis method, a lens that moves at a right angle to the optical axis is used as a part of the lens group, and the tilt of the optical axis can be controlled by this movement. The adoption of the optical axis correction by lens shift described above is effective from the viewpoint of realizing higher accuracy in preventing the deviation of the optical axis.

[0066] In the above embodiment, the wedge prism to be rotated is supported by an arc-shaped slit and a pin inserted therein. However, in the present invention, the support form of the vibration-proof lens group can be appropriately determined according to the type of vibration-proof lens group and the required driving distance. For example, the support form may include a long groove extending opposite to each of the portions of the frame plate and the cover facing the main surface of the frame plate in this embodiment, and a ball accommodated in the long groove of the combined frame plate and cover. The movement of the ball is restricted by the long groove, and exhibits the function of a bearing that smoothly rotates the frame plate (wedge prism). The installed ball can also exhibit the function of supporting the frame plate (wedge prism) from the side so that it can rotate with respect to the cover. Furthermore, by accommodating multiple balls in the long groove, it is also possible to rotatably support the wedge prism while distributing the weight of the wedge prism among the multiple balls. With this configuration as well, it is possible to support the anti-vibration lens from the side so that the range of rotational movement is defined by the long groove and so that the anti-vibration lens can be rotated even more smoothly.

[0067] In the above embodiment, two arc-shaped slits are formed and two pins are inserted into different arc-shaped slits, but two pins may be inserted into one arc-shaped slit. With this configuration, the wedge prism can be rotatably supported while the rotation direction of the wedge prism is regulated.

[0068] In the above-described embodiment, both the transmitting device 2 and the receiving device 3 in the free space optical communication system 1 are equipped with the vibration isolation unit 6. In the present invention, the vibration isolation unit may be installed in only one of the transmitting device and the receiving device, as long as the optical axis of the light of the communication signal in the free space optical communication can be corrected so that it can be transmitted and received between the transmitting device and the receiving device.

[0069] For example, when the magnitude of change in the orientation or position of the optical communication device is limited, stable optical space communication can be sufficiently realized even if only one of the transmitting and receiving devices is equipped with an anti-shake unit, as described above. In this case, the optical space communication system of the present invention can be configured with one of the transmitting and receiving devices equipped with the above-mentioned anti-shake unit, and the other of the transmitting and receiving devices not having the anti-shake unit.

[0070] 〔summary〕 As is clear from the above description, the vibration-proof unit for optical communication device (vibration proof unit 6) in the embodiment of the present invention has a vibration proof lens group (first correction lens group 11 and second correction lens group 12) and a controller (20) that specifies at least a change in the orientation or position of the optical communication device (transmitter 2, receiver 3) without referring to the signal light output from the optical communication device or input to the optical communication device, and corrects the tilt of the optical axis (OA) of the signal light by controlling the vibration proof lens group based on the specified change in the orientation or position. Also, the optical communication device in the embodiment of the present invention is equipped with the above-mentioned vibration proof unit for optical communication device. Furthermore, the optical space communication system in the embodiment of the present invention includes a transmitter and a receiver, and one or both of the transmitter and the receiver are equipped with the above-mentioned vibration proof unit for optical communication device. Therefore, according to the embodiment of the present invention, it is possible to eliminate the misalignment of the optical axis in optical space communication so as to realize stable optical space communication.

[0071] The optical communication device vibration isolation unit may further include a gyro sensor and an acceleration sensor, and the controller may identify changes in the orientation or position of the optical communication device by referring to the output signals of the gyro sensor and the acceleration sensor. This configuration is even more effective in identifying changes in the orientation or position of the optical communication device with high accuracy.

[0072] Furthermore, the inclusion of two pairs of wedge prisms (P1 to P4) in the vibration-proof lens group is even more effective in terms of increasing the correction angle of the tilt of the optical axis and making it possible to quickly identify the amount of operation for said correction.

[0073] In addition, in an embodiment of the present invention, the vibration-proof lens group may include, for each wedge prism, a movable frame (frame plate 111) that holds the wedge prism, a fixed frame (cover 102) that rotatably supports the movable frame, and a coil (113) provided on either or both of the movable frame and the fixed frame, and the movable frame may be rotated relative to the fixed frame by the magnetic force generated by the coil. This configuration is even more effective in terms of quickly rotating the wedge prism and eliminating the misalignment of the optical axis caused by high-frequency vibrations of the optical communication device.

[0074] Also, an arc-shaped slit (112) may be formed in the movable frame, and the fixed frame may have at least two pins (103) that pass through the slits. This configuration is even more effective in terms of accurately and quickly moving the wedge prism to a desired position in the rotational direction, by reducing the weight of the configuration for rotating the wedge prism. [Explanation of symbols]

[0075] 1. Optical space communication system 2. Transmitter (optical communication device) 3. Receiving device (optical communication device) 4 Panhead 5 Laser transmitter circuit 6 Anti-vibration unit (anti-vibration unit for optical communication equipment) 7 Laser receiving circuit 10 Optical axis adjustment unit 11 First correction lens group (anti-vibration lens group) 12 Second correction lens group (anti-vibration lens group) 13~16 Position sensor 20, 200 Controller 30 Sensor unit 101 Substrate 102 Cover 103 Pin 104 Magnet 110, 120, 210, 220 Wedge Prism Unit 111 Frame board 112 Slit 113 Coil A1, A11, A12, S arrows P1~P4 Wedge Prism

Claims

1. An image stabilizing lens group including two pairs of wedge prisms; a controller that determines a change in at least an orientation or a position of an optical communication device without referring to a signal light output from the optical communication device or input to the optical communication device, and corrects a tilt of an optical axis of the signal light by controlling the vibration-proof lens group based on the determined change in orientation or position; An anti-vibration unit for an optical communication device comprising:

2. 2. The vibration isolation unit for an optical communication device according to claim 1, further comprising a gyro sensor and an acceleration sensor, wherein the controller identifies a change in orientation or position of the optical communication device by referring to output signals from the gyro sensor and the acceleration sensor.

3. 3. The vibration-proof unit for an optical communication device as described in claim 1 or 2, wherein the vibration-proof lens group includes, for each wedge prism, a movable frame that holds the wedge prism, a fixed frame that rotatably supports the movable frame, and a coil provided on either or both of the movable frame and the fixed frame, and the movable frame is rotated relative to the fixed frame by a magnetic force generated by the coil.

4. 4. The vibration isolation unit for an optical communication device according to claim 3, wherein the movable frame has an arc-shaped slit, and the fixed frame has at least two pins that pass through the slit.

5. 5. An optical communication device comprising the vibration isolation unit for optical communication device according to claim 1.

6. 5. An optical free space communication system comprising a transmitting device and a receiving device, one or both of the transmitting device and the receiving device being provided with the vibration isolation unit for an optical communication device according to claim 1.

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