JP2007282144A - Optical space communication apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical space communication apparatus capable of reducing possibility that optical axis deviation may occur. <P>SOLUTION: A Z direction indicates the direction of an optical beam L turned to an opposite side apparatus 52 when a driving mechanism of the own apparatus 51 exists on a middle point. An optical beam radiation azimuth angle driving range in the vertical direction of an optical axis deviation correction mechanism in an initial adjustment mode is an angle B1, the driving range in the vertical direction in a normal operation mode is an angle B2 and the relation of B1<B2 is set. The Z direction of the optical beam L when the driving mechanism of the own apparatus 51 exists on the middle position is set to the center between the angle B1 and the angle B2. An angle B3 is a driving range of an upward portion exceeding the angle B1 from the own apparatus in the normal operation mode, an angle B4 is a driving range of a downward portion exceeding the angle B1, and the relation of B2=B1+B3+B4 is set. Consequently even when the own apparatus 51 is inclined due to some factor, the angles B3, B4 of which the optical axis deviation can be corrected can be secured in initial set, so that automatic tracing operation can be continued within the range. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is an optical space having a function of correcting an optical axis shift of a light beam due to an angle shift of an apparatus by communicating with an optical signal by a light beam propagating in a free space, facing two distant points. The present invention relates to a communication device.

  In general, an optical space communication device that performs communication by propagating a light beam in free space needs to transmit with a narrow light beam with a light beam divergence angle as small as possible in order to transmit light power efficiently. There is. However, if the light beam divergence angle is narrowed, the light beam is likely to be detached from the counterpart device due to wind pressure or vibration of the building or installation base, distortion due to temperature fluctuation, angular fluctuation due to time variation, etc., making stable communication difficult. It becomes. Therefore, as shown in Patent Document 1, for example, an apparatus having an optical axis deviation correction mechanism that corrects an angle change even when the angle of the apparatus changes and always directs the light beam toward the counterpart apparatus has been proposed. .

  FIG. 5 shows an apparatus for transmitting / receiving a light beam. A casing 3 is mounted on a pedestal 1 via an adjustment base 2, and a horizontal driving mechanism 4 is provided in the casing 3. An optical system 6 is provided via a vertical drive mechanism 5. The light emitting element 7 in the optical system 6 emits a light transmission / reception signal composed of laser light toward the lens 8 and the polarization beam splitter 9. The laser beam reflected by the polarization beam splitter 9 is emitted as a light beam L to the counterpart device via the light transmitting / receiving lenses 10 and 11.

  The light beam L transmitted from the counterpart device passes through the transmission / reception lenses 11 and 10, passes through the polarization beam splitter 9 as it is, enters the beam splitter 12, and is split in the beam splitter 12. The light enters the light receiving element 14 through the lens 13. The other light beam transmitted through the beam splitter 12 is incident on the optical position detection element 16 through the lens 15.

  FIG. 6 shows a schematic diagram of the optical position detection element 16. The optical position detection element 16 is composed of four divided photodiodes 16a to 16d, and the light spot S that has passed through the lens 15 is the photodiode 16a. ˜16d. The position of the light spot S can be detected by comparing the outputs of the four divided photodiodes 16a to 16d.

  A signal from the optical position detection element 16 is processed by the control circuit 17 as angle correction information, and a drive signal is output to the drive circuit 18. When the horizontal driving mechanism 4 and the vertical driving mechanism 5 are driven by the driving circuit 18, the position of the light spot S reaches the center of the light position detecting element 16, and all the outputs of the four divided photodiodes 16a to 16d are output. Driven and controlled in the same direction.

  The positions of the light emitting element 7, the light receiving element 14, and the optical position detecting element 16 are all adjusted so that their optical axes coincide. Therefore, in the state where the light spot S hits the center 16S of the light position detecting element 16, the light beam is also incident on the center of the light receiving element 14, and the center of the light beam from the light emitting element 7 is in the direction toward the counterpart device. A light beam is emitted toward.

  The optical axis deviation correction mechanism described above does not operate unless the light spot S is received by a part of the optical position detection element 16. In the initial adjustment at the time of installation of the apparatus, the operator sets the horizontal driving mechanism 4 and the vertical driving mechanism 5 to the initial position near the center of the driving range, and then sets the adjustment base 2 in a state where it can be driven up and down and left and right. Use to adjust the direction of the device. When the light spot S is received by a part of the light position detection element 16 by this direction adjustment, the optical axis deviation correction mechanism operates, and the operator fixes the adjustment base 2 in this state.

JP 11-346192 A

  In the above-described conventional example, since the operator manually adjusts the direction of the apparatus, the direction of the housing 3 cannot be immediately determined even after the optical axis deviation correction mechanism is operated, and moves somewhat. When the adjustment base 2 is fixed in this state, the horizontal driving mechanism 4 and the vertical driving mechanism 5 are not necessarily near the midpoint of the driving range. If the drive range of the horizontal drive mechanism 4 and the vertical drive mechanism 5 is close to the end of the drive range at the beginning of installation, it is normal if the device tilts for some reason during normal operation. In some cases, optical axis deviation correction cannot be performed.

  FIG. 7 shows the driving range of the radiation azimuth angle of the light beam, and shows the vertical azimuth angle for explanation. The light beam L is emitted from the own device 21 toward the counterpart device 22, and the direction of the light beam L is the Z direction when the drive mechanism of the own device 21 is at the midpoint position. The angle A1 is a driving range of the vertical azimuth angle of the light beam L, the angle A2 is a driving range of the downward azimuth angle of the device 21 when the optical axis deviation correction mechanism is operated, and the angle A3 is an upward azimuth direction. The angular drive range is shown.

  For example, when A2 << A3 during the operation of the optical axis deviation correction mechanism as shown in FIG. 6, the optical axis deviation can be corrected for a large downward displacement of the apparatus 21. However, since a large upward displacement exceeds the driving range of the optical axis deviation correction mechanism, the optical axis deviation cannot be corrected and the optical axis is off.

  An object of the present invention is to provide an optical space communication device capable of solving the above-described problems and reducing the possibility of occurrence of off-axis.

  In order to achieve the above object, the technical feature of the optical space communication device according to the present invention is that an optical beam transmitted to a counterpart device in an optical space communication device that communicates with a light beam by being opposed to each other between distant points. A light transmitting unit composed of a light emitting element and a transmitting optical system, a light receiving unit composed of a receiving optical system and a light receiving element for receiving a light beam from the counterpart device, and the arrival of the light beam from the counterpart device An optical position detection means for detecting a direction; a control means for controlling the azimuth angle of the optical transmission section and the optical reception section by a signal from the optical position detection means; and the azimuth angle by a signal from the control means An optical axis deviation correction mechanism that adjusts the azimuth angle driving range, the optical axis deviation correction mechanism includes an adjustment mode that limits the azimuth angle driving range to within a threshold value, and a normal mode that does not limit the azimuth angle driving range to within the threshold value And It is to.

  The optical space communication apparatus according to the present invention is less likely to cause off-axis during operation.

  The present invention will be described in detail based on the embodiment shown in FIGS.

  FIG. 1 is a configuration diagram of an optical space communication device according to the first embodiment, and shows only one of a pair of devices for transmitting / receiving opposing light beams. On the fixed base 31 for installation, a housing 33 is installed via an adjustment base 32 that roughly adjusts and fixes the direction of the apparatus. An optical system 36 is provided in the housing 33 via a horizontal driving mechanism 34 and a vertical driving mechanism 35.

  In the optical system 36, light transmitting / receiving lenses 37 and 38, a polarizing beam splitter 39, a beam splitter 40, a lens 41, and an optical position detecting element 42 are sequentially arranged from the counterpart device side. A lens 43 and a light emitting element 44 including a semiconductor laser light source are provided in the incident direction of the polarization beam splitter 39, and a lens 45 and a light receiving element 46 are provided in the branching direction of the beam splitter 40.

  The output of the optical position detection element 42 is connected to the control circuit 47, and the output of the control circuit 47 is connected to the drive mechanisms 34 and 35 via the drive circuit 48. Further, the control circuit 47 is connected to the output of a setting unit 49 for setting the irradiation azimuth driving range of the light beam L in the initial adjustment mode and switching between the initial adjustment mode and the normal operation mode at the time of position setting.

  The setting unit 49 is housed in the housing 33. However, instead of the setting unit 49, a similar function can be performed by connecting an external computer to the control circuit 47 via a network. is there.

  When laser light polarized so that the polarization direction is horizontal to the paper surface is emitted from the light emitting element 44 toward the lens 43 and the polarization beam splitter 39, the laser light reflected by the polarization beam splitter 39 is transmitted to the light transmitting / receiving lens 38, After going through 37, the light is emitted toward the counterpart device. At this time, the light transmitting / receiving lens 37 becomes a substantially horizontal light beam L having a slight spread.

  Further, since the light beam L transmitted from the counterpart device has the polarization direction set perpendicular to the paper surface and is orthogonal to the transmission light, it passes through the polarization beam splitter 39 through the transmission / reception lenses 37 and 38 as it is. , Enters the beam splitter 40. Then, the light beam L is split into two in the beam splitter 40, and most of the light beam L is incident on the light receiving element 46 through the lens 45. The other light beam that has passed through the beam splitter 40 enters the optical position detection element 42 through the lens 41.

  The signal obtained by the optical position detection element 42 is output to the drive circuit 48 via the control circuit 47, and the drive signal from the drive circuit 48 is output to the drive mechanisms 34 and 35.

  FIG. 2 shows the driving range of the light beam radiation azimuth angle in the initial adjustment mode and the normal operation mode of the space optical communication apparatus in the present embodiment, and the light beam L is directed from the own apparatus 51 toward the counterpart apparatus 52. It is emitted. The Z direction indicates the direction of the light beam L when the drive mechanism of the apparatus 51 is at the midpoint position. Here, for the sake of explanation, the driving range of the vertical light beam radiation azimuth is shown.

  The light beam azimuth driving range of the optical axis deviation correction mechanism in the initial adjustment mode is the angle B1, the driving range in the normal operation mode is the angle B2, and B1 <B2. Further, the Z direction of the light beam L when the driving mechanism of the apparatus 51 is at the midpoint position is set at the center between the angles B1 and B2. The angle B3 is a drive range of the upward portion beyond the angle B1 from the own apparatus in the normal operation mode, the angle B4 is a drive range of the downward portion beyond the angle B1, and B2 = B1 + B3 + B4.

  The driving range in the horizontal initial adjustment mode and the normal operation mode is set independently of the vertical direction, but the operation principle is the same.

  FIG. 3 is a flowchart of the initial adjustment method when the optical space communication apparatus is installed. In the initial adjustment at the time of installation of the apparatus, first, in step S1, the initial adjustment mode is set via the setting unit 49, and the driving range of the light beam radiation azimuth angle in the initial adjustment mode is set to an angle B1, an angle as shown in FIG. Set in the center direction of B2.

  Subsequently, in step S2, the control circuit 47 instructs the drive circuit 48 to set the horizontal drive mechanism 34 and the vertical drive mechanism 35 to the initial position near the middle point, so that the light beam L is changed to the figure. The light is emitted in the Z direction shown in FIG. Subsequently, in step S3, the angle is limited to the angle B1 with the Z direction of the light beam L as the center when the drive mechanism of the apparatus 51 is at the midpoint position.

  In step S4, the operator manually adjusts the direction of the apparatus with the adjustment base 32 being movable up, down, left and right, and then determines the operation of the automatic tracking function in step S5. That is, when the light spot S is received by a part of the light position detecting element 42 by the direction adjustment, the optical axis deviation correcting mechanism operates, and if it is determined that the automatic tracking function is operated, the process proceeds to step S6, and the operation is performed in that state. The person fixes the adjustment table 32. When the light spot S does not enter the light position detecting element 42 and the automatic tracking function does not operate, the process returns to step S4, and the adjustment table 32 is adjusted again.

  In step S7, it is determined whether or not the automatic tracking operation is continued. If the automatic tracking operation is continued, the process proceeds to step S8. When not continuing, it returns to step S4, the fixation of the adjustment stand 32 is cancelled | released, and direction adjustment of an apparatus is performed again. In the initial adjustment mode, there is a possibility that the counterpart device is installed in the direction beyond the driving range of the light beam azimuth angle. Repeat the adjustment operation.

  When the automatic tracking operation continues, the direction of the light beam L is within the range of the angle B1 shown in FIG. Subsequently, in step S8, in a state where the adjustment base 32 is fixed and the optical axis deviation correction operation is continued, the normal operation mode is set via the setting unit 49. In step S9, the normal operation mode is set to release the restriction on the driving range of the light beam radiation azimuth, and the original angle B2 is set as the optical axis deviation correction possible range.

  As a result, even if the device 51 tilts for some reason after installation, the angles B3 and B4 that can correct the optical axis deviation at the time of initial installation are secured, so that the automatic tracking operation is continued within that range. Can do.

  FIG. 4 shows the driving range of the vertical light beam azimuth angle in the initial adjustment mode and the normal operation mode in the second embodiment. As in the first embodiment, the driving range in the initial adjustment mode is the angle B1, the driving range in the normal operation mode is the angle B2, and B1 <B2. Further, the Z direction of the light beam L when the drive mechanism of the apparatus 51 is at the midpoint position is set at the center of the angle B2. The angle B3 is the driving range of the upward portion that exceeds the angle B1 from the own device 51 in the normal operation mode, the angle B4 is the driving range of the downward portion that exceeds the angle B1, and has a relationship of B2 = B1 + B4 + B3.

  As shown in FIG. 4, in the second embodiment, the angle B1 of the optical axis deviation correction mechanism in the initial adjustment mode is set in the lower direction with respect to the midpoint direction. If it is clear that the device 51 is likely to move in the downward direction rather than the upward direction, the setting unit 49 sets the angle B1 in this way, and the initial adjustment is performed as in the first embodiment. To do. As a result, even if the device 51 is directed downward, the movable range in the downward direction is wider than the upward direction, so that the possibility of off-axis during the optical axis deviation correction operation is reduced. .

  That is, when there is a high possibility that the direction is directed in advance, the angle B1 is set in the direction. Further, since the angles B1 in the vertical direction and the horizontal direction are set independently, it is most effective to set them at the optimum position and range.

  In the embodiment, the adjustment mode is described as the initial adjustment mode. However, this adjustment mode is not only applied at the time of setting, but can be arbitrarily adjusted.

  In this adjustment mode in each embodiment, after the operation range of the drive mechanism is limited to the vicinity of the midpoint, the adjustment by the adjustment stand 32 is performed until the light position detection element receives the light spot S. Until the light position detecting element receives the light spot S, the drive range of the drive mechanism is set as wide as in the normal operation mode, and after receiving the light spot S, the drive range is reduced while being adjusted by the adjustment base 32. It is good also as composition to do. According to this configuration, the light spot S of the counterpart device can be detected smoothly, and the possibility that the optical axis may be off can be reduced by appropriately performing the adjustment using the adjustment base 32.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist thereof.

It is a block diagram of the optical space communication apparatus of Example 1. FIG. It is a figure showing the drive range of a light beam radiation azimuth. It is a flowchart figure of the initial adjustment method. 6 is a diagram illustrating a driving range of a light beam radiation azimuth angle according to Embodiment 2. FIG. It is a block diagram of the conventional optical space communication apparatus. It is the schematic of an optical position detection element. It is a figure showing the drive range of the conventional light beam radiation azimuth.

Explanation of symbols

34 Horizontal driving mechanism 35 Vertical driving mechanism 42 Optical position detection element 44 Light emitting element 46 Light receiving element 47 Control circuit 48 Drive circuit 49 Setting unit 51 Self device 52 Counterpart device

Claims (3)

  In an optical space communication apparatus that communicates with a light beam by being installed facing each other between distant points, a light transmitting unit that includes a light emitting element that generates a light beam to be transmitted to a counterpart apparatus and a transmission optical system, and the counterpart apparatus A light receiving unit comprising a receiving optical system and a light receiving element for receiving the light beam, a light position detecting means for detecting the direction of arrival of the light beam from the counterpart device, and a signal from the light position detecting means Control means for controlling the azimuth angle of the light transmission unit and the light reception unit, and an optical axis deviation correction mechanism for adjusting the azimuth angle according to a signal from the control means, the optical axis deviation correction mechanism, An optical space communication apparatus comprising: an adjustment mode that limits the azimuth angle driving range to within a threshold; and a normal mode that does not limit the azimuth angle driving range to within the threshold.   2. The optical space communication apparatus according to claim 1, wherein the adjustment mode can set an angle of the azimuth driving range to be limited.   3. The optical space communication apparatus according to claim 2, wherein the limiting azimuth angle is set in advance to be a large angle at which the light beam is easily directed.

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