JP3038881B2 - Optical space transmission equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in the following order.

A Industrial application field B Outline of the invention C Conventional technology (Fig. 19) D Problems to be solved by the invention (Fig. 19) E Means for solving the problems (Figs. 2, 6 and 7
Figure) F action (FIGS. 2, 6 and 7) G embodiment (FIGS. 1 to 18) (G1) Schematic configuration of optical space transmission apparatus (FIG. 1) (G1-2) Transmission Optical system (Fig. 2) (G1-3) Collimating scope (Fig. 2) (G1-4) Anti-reflection mechanism (Fig. 2) (G1-5) Arrangement of collimating scope (Figs. 2 and 3) (G1-6) Servo circuit (Figs. 1 to 18) (G1-6-1) Polarization correction (G1-6-2) Irradiation position correction (G1-6-3) Servo stop control ( G1-6-4) Configuration of mirror (G1-7) System control circuit (G2) Operation of embodiment (G3) Effects of embodiment (G4) Other embodiments Effects of H Invention A Industrial application field The present invention TECHNICAL FIELD The present invention relates to an optical space transmission device, and more particularly, to an optical space transmission device that transmits desired information via a light beam that transmits space.

Summary of the Invention The present invention, in the optical space transmission device, by detecting the extreme decrease in the amount of incident light, or sunlight, to stop the correction operation and the like of the irradiation position of the light beam as necessary,
The usability of the optical space transmission device can be improved.

C Conventional Technology Conventionally, in an optical space transmission apparatus, a part of a light beam having a predetermined polarization plane to be transmitted to a transmission target is folded and observed together with observation light arriving from the transmission target, thereby easily irradiating the light beam. There have been proposed ones capable of confirming the position (Japanese Patent Application No. 2-20916, Japanese Patent Application No. 63-138).
No. 120).

That is, as shown in FIG. 19, in the optical space transmission device 1, the laser diode 2 is driven by a predetermined information signal, and the laser beam from the laser diode 2 has a predetermined polarization plane.
Irradiate LA1.

The lens 4 converts the light beam LA1 into a parallel light beam, transmits the light beam LA1 through the polarizing prism 6, and guides the light beam LA1 to the half mirror 8.

Here, the half mirror 8 transmits a part of the light beam LA1 and transmits the transmitted light to the transmission target via the lenses 16 and 18.

As a result, the optical space transmission device 1 sends out the light beam LA1 having a predetermined polarization plane to the transmission target.

Further, the half mirror 8 returns the reflected light of the light beam LA1 by the corner tube prism 10 and guides the returned light beam to the image pickup device 14 via the lens 12.

As a result, in the optical space transmission device 1, a part of the light beam LA1 sent to the transmission target is separated, and its optical path is turned back so as to be focused on the image sensor 14.

The lens 18 receives the light beam LA2 arriving from the transmission target and guides the light beam LA2 to the polarizing prism 6 via the lens 16 and the half mirror 8.

Here, in the transmission target, a light beam LA2 whose polarization plane is orthogonal to the light beam LA1 is emitted.

As a result, the optical space transmission device 1 reflects the light beam LA2 on the polarizing prism 6 and then focuses the light beam LA2 on the light receiving element 22 via the lens 22.

Thus, the optical free space transmission device 1 can receive the light beam LA2 arriving from the transmission target and receive the information.

Further, the lens 18 receives, together with the light beam LA2, light L1 (hereinafter referred to as observation light) from the scenery around the transmission target toward the optical space transmission device 1, and transmits the observation light L1 to the lens 16,
The light is guided to the image sensor 14 via the half mirror 8 and the lens 12.

As a result, in the observation light L1, a component parallel to the light beam LA1 and the optical axis enters the lens 12 in parallel with the reflected light from the corner cube prism 10.

Therefore, the light reflected by the corner cube prism 10 enters the lens 12 in an optical path as if it were emitted from the irradiation position of the light beam LA1 toward the optical space transmission device 1.

As a result, in the optical space transmission device 1, the image sensor 14
Thus, a captured image in which a bright luminescent spot is formed at the irradiation position of the light beam LA1 can be obtained, and the irradiation position of the light beam LA1 can be easily confirmed.

Problem to be Solved by the Invention By the way, it would be convenient if the optical space transmission device 1 could be reduced in size.

That is, in the optical space transmission device 1, the light beam LA1
By being able to easily detect the irradiation position of
Installation work can be simplified.

Therefore, it can be installed at a desired installation location as needed and used for, for example, television broadcasting.

However, in this case, the irradiation position of the light beam LA1 may be displaced due to vibration or the like.

As one method of solving this problem, there is a method of correcting the irradiation position of the light beam LA1 based on the light beam LA2 arriving from the transmission target using a servo method.

However, according to this method, when fog or the like is generated,
When sunlight is incident, the light beam LA1 may be radiated in a direction completely unrelated to the transmission object, and after the fog has cleared or the sunlight has stopped entering, the servo is applied again. There was a problem that the irradiation position of the light beam LA1 had to be readjusted.

That is, when fog occurs, the intensity of the light beam LA2 extremely decreases, and the output signal level of the light receiving element that detects the light beam LA2 decreases.

Accordingly, the SN ratio of the output signal is degraded, and the light beam LA1 is erroneously irradiated in a direction completely unrelated to the transmission target.

When sunlight enters, the irradiation position of the light beam LA1 is corrected in the direction of the sun.

The present invention has been made in view of the above points, and an object of the present invention is to provide an optical space transmission apparatus which can improve the usability by omitting such readjustment of the irradiation position.

Means for Solving Problem E In order to solve the problem, in the first invention, a transmission light beam of a predetermined polarization plane W1 modulated by a predetermined information signal S1 is provided.
LA1 is transmitted to a transmitting / receiving device that is arranged at a predetermined distance, and a predetermined polarization plane transmitted from the transmitting / receiving device.
By receiving the reception light beam LA2 of W2, the information signal S1 is transmitted to the transmission / reception device via the transmission light beam LA1, and the predetermined information signal S2 transmitted from the transmission / reception device via the reception light beam LA1 is received. In the optical space transmission apparatus 30, the light source 51 that emits the transmission light beam LA1, and the transmission light beam LA1 emitted from the light source 51 is reflected or transmitted, and the reception light beam LA2 is transmitted in reverse to the transmission light beam LA1. A transmitting / reflecting polarized light beam separating means 53 and a transmitting light beam LA1 obtained through the polarized light beam separating means 53 are transmitted to the transmitting / receiving device, and a receiving light beam LA2 coming from the transmitting / receiving device is polarized light beam separating means. Optical system 59 leading to 53
A, 59B, light receiving sections 64, 68 for receiving the received light beam LA2 obtained through the polarized light beam separating means 53, and light receiving sections 64, 6
Irradiation position correction means 56, 57, 59B, 6 for correcting the irradiation position of the transmission light beam LA1 based on the eight output signals IX1-1Y2.
0, 61, 86A, 86B, 91 and the output signals IX1 of the light receiving sections 64, 68
IIY2, the incident light amount of the received light beam LA2 is detected, and when the incident light amount falls below a predetermined value, the operation of the irradiation position correction means 56, 57, 59B, 60, 61, 86A, 86B, 91 is stopped. Control means 65 and 94 for controlling are provided.

Further, in the second invention, a transmission light beam LA1 on a predetermined polarization plane W1 modulated by a predetermined information signal S1 is transmitted to a transmission / reception device arranged at a predetermined distance from the transmission / reception device. Received light beam LA on polarization plane W2
2, the information signal S1 is transmitted to the transmitting / receiving device via the transmission light beam LA1, and the reception light beam LA
2, a predetermined information signal S2 transmitted from the transmitting / receiving device
In the optical space transmission device 30 that receives the
A light source 51 that irradiates 1 and a reflected or transmitted transmission light beam LA1 emitted from the light source 51, and a polarized light beam separation unit 53 that transmits or reflects the reception light beam LA2 opposite to the transmission light beam LA1, Transmitting the transmission light beam LA1 obtained through the polarized light beam separation means 53 to the transmission / reception device,
Optical systems 59A and 59B for guiding the received light beam LA2 coming from the transmitting / receiving device to the polarized light beam separating means 53, and the received light beam LA2 obtained through the polarized light beam separating means 53 are received via a predetermined filter 67. A light receiving unit 68 and sunlight detecting circuits 65, 96, and 97 for detecting the incidence of sunlight on the optical systems 59A and 59B based on the output signal of the light receiving unit 68 are provided.

F action Based on the output signals of the light receiving sections 64 and 68, the received light beam LA
If the incident light amount of No. 2 is detected, it is possible to easily detect the light amount of the received light beam LA2 or less.

Therefore, when the incident light amount was reduced to a predetermined value or less, the operation of the irradiation position correction means 56, 57, 59A, 60, 61, 86A, 86B, 91 was stopped and controlled, so that the light amount of the reception light beam LA2 was increased. In this case, the servo operation can be started immediately.

Further, the received light beam LA2 is transmitted through a predetermined filter 67.
If the output signal of the light receiving unit 68 that receives the light is detected, the incidence of sunlight can be detected, and the servo operation or the like can be stopped and controlled as necessary.

G Example Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

(G1) Schematic Configuration of Space Optical Transmission Device In FIG. 1, reference numeral 30 denotes an entire space optical transmission device, which can be driven by a power supplied from a power supply device 31.

That is, the power supply device 31 houses the battery inside, and when the power switch 31A provided on the front surface is turned on,
The battery power is supplied to the optical space transmission device main body 34 via the cable 31B.

Thereby, the optical space transmission device main body 34 rises to an operating state in response to the operation of the power switch 31A provided on the power supply device 31 side, and thus, in the optical space transmission device 30,
The battery can be easily replaced on the power supply device 31 side.

The optical space transmission device main body 34 is mounted on a gantry 35 and can be installed at a predetermined position. The optical space transmission device main body 34 is provided through a display screen 36 on an operation panel as necessary.
The irradiation position of the light beam LA1 emitted from the device can be confirmed.

Further, the optical space transmission device main body 34 has an initialization switch 37 at the upper part of the operation panel, and when the initialization switch 37 is turned on, the irradiation position adjustment mechanism of the light beam LA1 is installed at the operation center. It has been fixed.

In addition, the optical space transmission device main body 34 has operators 38A to 37D for adjusting the irradiation position below the initializing switch 37,
When the operators 38A to 38D are turned on, the irradiation position of the light beam LA1 can be adjusted in four directions, up, down, left and right, corresponding to the operators 38A to 38D, respectively.

Furthermore, after adjusting the irradiation position of the light beam LA1, the optical space transmission device body 34 corrects the irradiation position of the light beam LA1 based on the light beam LA2 arriving from the transmission target when the servo switch 39 is turned on. The correction state can be visually confirmed by turning on the light emitting elements 40A and 40B.

Further, a monitor switch 41 is provided below the servo switch 39.
And a zoom operator 42, and the monitor switch 41
When the zoom operator 42 is turned on, the display screen is turned on and the magnification of the display screen is changed.

A monitor indicator 43 is arranged below the display screen 36, and the pointer of the indicator 43 can monitor the light intensity of the light beam LA2 coming from the transmission target.

Further, connectors 44 and 45 are arranged below the operation panel, and output received video signals and communication signals to the outside.

(G1-2) Transmission Optical System As shown in FIG. 2, the optical space transmission device main body 34 accommodates a transmission optical system 48 in a rectangular casing, and
The optical beams LA1 and LA2 are transmitted / received to / from the transmission target via 48.

That is, the drive circuit 50 transmits a desired information signal to be transmitted.
The laser diode 51 is driven in S1.

The laser diode 51 is held at a predetermined inclination with respect to the housing of the optical space transmission device main body 34, thereby tilting the polarization plane W1 by approximately 45 degrees with respect to the horizontal axis of the optical space transmission device main body 34. Irradiated light beam LA1.

The lens 52 converts the light beam LA1 emitted from the laser diode 51 into a parallel light beam, passes through the polarizing prism 53, and guides the light beam to the mirror 56 via the lens 54 and the lens 55.

Here, the mirror 56 is disposed at an angle of 45 degrees with respect to the optical axis of the light beam LA1, thereby bending the optical axis of the light beam LA1 in the horizontal direction by approximately 90 degrees.

On the optical axis of the bent light beam LA1, a mirror 57 similarly inclined at 45 degrees with respect to the optical axis of the light beam LA1 is arranged, whereby the light beam bent by the mirror 56 is provided.
Fold the optical axis of LA1 almost parallel to the original optical axis.

At this time, the mirrors 56 and 57 are rotated by a small angle in the horizontal and vertical directions as indicated by arrows a and b, respectively, based on the drive signals SX1 and SY1 output from the servo circuit 58.

Accordingly, the mirrors 56 and 57 displace the optical axis of the light beam LA1 by a small angle in the vertical and horizontal directions, and finely correct the irradiation direction of the light beam LA1 emitted from the optical space transmission device main body.

The lens 59A converges the light beam LA1 reflected by the mirror 57, and then transmits the light beam LA1 to the transmission target via the lens 59B, thereby transmitting the light beam LA1 to the transmission target in a predetermined spread.

At this time, as shown by arrows c and d, the lens 59A
Drive signals SX2 and S output from the servo circuit 58 are rotated by the motors 60 and 61 in the vertical and horizontal directions.
The emission direction of the light beam LA1 is roughly adjusted based on Y2.

As a result, in the optical space transmission device main body 34, the mirror
Even if the optical space transmission device main body vibrates due to wind or the like by moving the lenses 56 and 57 and the lens 59A, the light beam LA1 is reliably irradiated to the transmission target.

The light beam LA2 arriving from the transmission target is received by the lens 59B, reverses the optical path of the light beam LA1, and enters the polarizing prism 53.

Here, in the light beam LA2, the polarization plane of the light beam LA1
Light is emitted from the transmission target such that the polarization plane W2 is orthogonal to W1.

Thus, the light beam LA2 is reflected by the polarizing prism 53 and enters the half mirror 62.

Here, the half mirror 62 transmits the light beam LA2 to the lens 6
The light is condensed on the light receiving element 64 via 3.

Thus, in the optical space transmission apparatus main body 34, the output signal of the light receiving element 64 is demodulated by the signal processing circuit 65, so that the information signal S2 transmitted from the transmission target is received.

Further, the half mirror 62 reflects the light beam LA2, and condenses the light beam LA2 on the light receiving surface of the position detection sensor 68 via the filter 66 and the condenser lens 67.

Here, the position detection sensor 68 is formed of a two-dimensional position detection sensor that outputs output signals IX1 to IY2 corresponding to the position of the light spot formed on the light receiving surface, and outputs the output signals IX1 to IY2 of the position detection sensor. Based on the optical space transmission device body
The emission position of the light beam LA2 with respect to 34 can be detected with high accuracy.

That is, the servo circuit 58 performs an addition / subtraction process on the output signals IX1 to IY2 to generate an error signal, and outputs drive signals SX1 to SY2 based on the error signal.

Accordingly, the servo circuit 58 corrects the irradiation position of the light beam LA1 with reference to the light beam LA2, and even if the optical space transmission device main body 34 vibrates due to wind or the like, the light beam LA1
Is transmitted to the transmission target without fail.

(G1-3) Collimating Scope A collimating scope A is arranged on the optical path between the mirror 57 and the lens 59A, so that the irradiation position of the light beam LA1 can be visually confirmed on the display screen 36.

That is, the collimator scope A arranges the half mirror 69 on the optical path of the light beam LA1, and reflects a part of the light beam LA1.

At the same time, the half mirror 69 transmits the observation light L1 traveling from the scenery around the transmission target to the optical space transmission device 1 through the lenses 59B, 5B.
After being received via 9A and reflecting the observation light L1 in the direction opposite to the light beam LA1, the light enters the imaging optical system 70.

The corner cube prism 71 receives the reflected light LR1 of the light beam LA1 and turns the optical path of the reflected light LR1 in parallel, and then guides the reflected light LR1 to the imaging optical system 70 via the half mirror 69.

The imaging optical system 70 condenses the reflected light LR1 and the observation light L1 on a built-in imaging device, and outputs an output signal of the imaging device to the imaging signal processing circuit 72.

The imaging signal processing circuit 72 converts the output signal of the imaging device into a video signal, and outputs the video signal to the monitor device 73, thereby transmitting the light beam LA1 onto the scene to be transmitted via the display screen 36 on the operation panel. The irradiation position can be observed as a bright luminescent spot.

At this time, in the imaging optical system 70, the zoom drive circuit 74
To change the magnification.

Thereby, in the optical space transmission device body 34, after roughly adjusting the irradiation position of the light beam LA1 at a low magnification, sequentially increasing the magnification and adjusting again, and operating the servo circuit 58 in a predetermined range, Easy light beam LA1
Can be adjusted.

(G1-4) Anti-reflection mechanism Here, corner cube prism 71 and half mirror
A shutter 75 is interposed between the 69, and the shutter is opened and closed as necessary, so that the light beam LA1 does not return to the light receiving element 64 during communication.

That is, in the shutter 75, the shutter driving circuit 76
, And switches from the light-shielded state to the open state in conjunction with the imaging signal processing circuit 72.

This allows the optical space transmission device main body 34 to be connected to the monitor switch.
When the 41 is turned on, a display image can be formed on the display screen 36 and the irradiation position of the light beam LA1 can be confirmed through the display screen based on the control signal SC1 output from the system control circuit 77. It has been made like that.

Therefore, after adjusting the irradiation position of the light beam LA1, by switching the monitor switch 41 to the off state,
The optical path of the light beam LA1 reflected by the half mirror 69 can be blocked.

That is, when the shutter 71 is closed, the light beam LA1 reflected by the half mirror 69 is turned into the corner cube prism 71.
After being turned back, half mirror 69, mirror 57, 56, lens 55, 54, polarizing prism 53, half mirror 62, lens
The optical path up to the light receiving element 64 via 63 can be blocked.

Therefore, the occurrence of crosstalk can be reduced and the information can be received reliably.

In this case, the light beam LA1 can be prevented from returning to the laser diode 51 at the same time, and the light beam LA1
Can be injected.

(G1-5) Arrangement of Collimating Scope As shown in FIG. 3, the collimating scope A is housed in a predetermined housing 78, and rotates around the optical axis of the lens 59B as shown by an arrow e. Have been made to gain.

That is, the housing 78 is provided with windows 69A and 69B before and after the half mirror 69, and the cylindrical projections of the holding members 79A and 79B are fitted to the windows 69A and 69B, and are held from the front and rear.

As a result, the light beams LA1, LA2 and the observation light L1 are incident on the half mirror 69 via the tubular introduction portions 79C and 79D formed inside the windows 69A and 69B.

As shown in FIG. 4, the holding members 79A and 79B have their roots fixed to the housing 80 of the optical space transmission device main body 34, so that the windows 69A and 69B slide with respect to the cylindrical projections. Thus, the entire collimator scope A can rotate around the optical axis of the lens 59B.

Further, in this embodiment, the casing 80 is formed in a rectangular shape, whereas the collimator scope A is
Is held in a diagonal direction.

That is, when the optical space transmission apparatus is configured using the collimator scope A in this manner, it is inevitable that the corner cube prism 71 and the imaging optical system 70 protrude from the lens barrel of the transmission optical system 48. However, the overall shape becomes larger.

Furthermore, the increase in the size increases the weight, and the portability is impaired.

Therefore, in the optical space transmission device main body 34, by holding the collimating scope A in a diagonal direction, the collimating scope A can be housed by effectively utilizing the internal space of the housing 80, and the overall shape can be reduced in size. Can be

Therefore, the overall weight can be reduced by that much, and the portability can be improved.

Further, by holding the lens 59A so as to be rotatable with respect to the optical axis of the lens 59A, the collimator scope A can be arranged at various inclinations according to the shape of the housing 80 to be incorporated and the arrangement of components in the housing 80. Therefore, the transmission optical system can be commonly used for various optical space transmission apparatuses.

At this time, the corner cube prism of the housing 78
In the accommodating portion 71 (that is, the upper portion of the housing 78), a corner portion extending forward and backward is formed to be largely chamfered according to the shape of the corner cube prism 71.

As a result, in the housing 78, the collimator scope A
When the collimating scope A is held by holding the collimating scope A while tilting the whole diagonally,
It is made so that there is no useless space inside.

By the way, when the collimator scope A is held in such an inclined manner, an inclined display image is displayed on the display screen 36 accordingly.

For this reason, in the imaging optical system 70 of the collimator scope A, as shown by an arrow f, the imaging optical system 70 of the collimator scope A is held rotatably about the optical axis of the imaging optical system 70. I have.

Accordingly, in the optical space transmission device main body 34, the imaging optical system 70 is rotated in accordance with the inclination of the collimator scope A, so that the horizontal and vertical directions are correctly displayed on the display screen 36.

In the image pickup optical system 70 as well, similarly to the storage section of the corner cube prism 71, the tip is formed so as to be small, so that useless space is not generated in the housing 80.

Thus, the overall shape can be reduced in size, and the usability of the optical space transmission device 30 can be improved accordingly.

(G1-6) Servo Circuit The servo circuit 58 rises to the operating state when the control signal SC2 is output from the system control circuit 77 in response to the operation of the servo switch 39 and the initializing switch 37.

Thereby, the servo circuit 58 corrects the irradiation position of the light beam LA1 and the polarization plane W1 of the beam LA1, based on the output signals IX1 to IY2 of the position detection sensor 68, so that information can be reliably transmitted and received. I have.

(G1-6-1) Correction of Polarization Surface As shown in FIG. 5, in the transmission optical system 48, the optical system from the laser diode 51 to the polarizing prism 53, the position detecting sensor 68 and the light receiving element from the polarizing prism 53 Up to 64 optical systems are integrally held by the lens barrel 81.

At this time, the polarization prism 53 is held so that the polarization plane in the transmission direction coincides with the polarization plane W1 of the laser diode 51.

Accordingly, in the optical space transmission device main body 34, when the polarization plane W1 of the light beam LA1 is accurately maintained at an inclination of 90 degrees with respect to the light beam LA2, the light beam LA2 incident on the polarizing prism 53 becomes The light beam LA2 is totally reflected by the prism 53 and is incident on the position detection sensor 68 most efficiently.

The lens barrel 81 rotates as shown by an arrow g with respect to the main body of the transmission optical system 48 (that is, the optical system from the mirror 56 to the lens 59B) via bearings 81A and 81B arranged so as to surround the periphery. It is held freely.

Thereby, the optical space transmission device main body 34 can adjust the polarization plane W1 of the light beam LA1 with respect to the polarization plane W2 of the light beam LA2 by rotating the lens barrel 81 and holding it at a predetermined position. I have.

That is, in the servo circuit 58, the polarization plane servo circuit 82
Outputs the output signals IX1 to IY2 of the position detection sensor 68 to the detection circuit 83.
Give to.

The detection circuit 83 detects the light intensity of the light beam LA2 incident on the position detection sensor 68 by adding the output signals IX1-1Y2.

The comparison circuit 84 takes in the detection result of the detection circuit 83 at a predetermined cycle and sequentially obtains the comparison result, thereby obtaining the position detection sensor.
A change in the amount of light of the light beam LA2 incident on 68 is detected.

When the control signal SC2 rises, the drive circuit 85 drives the motor 86 based on the detection result, thereby rotating the lens barrel 81 in a direction in which the incident light amount of the position detection sensor 68 increases, and the incident light amount decreases. Then, the rotation direction is switched.

As a result, the optical space transmission device body 34 is
The light beam L2 such that the polarization plane W2 of the light beam LA2 and the polarization plane W1 of the light beam LA1 are orthogonal to each other based on the amount of incident light at 68.
The polarization plane W1 of A1 and the polarization plane of the polarizing prism 53 are corrected.

Accordingly, even when the optical space transmission device main body 34 is installed at an angle, the polarization plane is automatically adjusted, and the light beam LA2 can be efficiently incident on the light receiving element 64. It can be simplified.

Further, even when the entire optical space transmission device 34 oscillates right and left, the polarization plane is automatically adjusted and the light beam LA is adjusted.
2 can be efficiently incident on the light receiving element 64.

Therefore, even when transmitting desired information mounted on a ship, a vehicle, an aircraft, a satellite, or the like, the information can be reliably received.

Further, for the transmission target, the light beam LA1 in which the 90-degree polarization plane W1 is tilted accurately with respect to the polarization plane W2 of the light beam LA2 can be transmitted, and the transmission target can reliably receive the light beam LA1 correspondingly, Thus, the information signals S1 and S2 can be reliably transmitted and received.

(G1-6-2) Correction of Irradiation Position As shown in FIG. 6, in the servo circuit 58, the output signals IX1 to IY2 of the position detection sensor 68 are converted into an X-direction position detection circuit.
86A and the Y-direction position detection circuit 86B.
Detect X and VERY.

That is, as shown in FIG.
A supplies output signals IX1 and IX2 of the position detection sensor 68 to the current-voltage conversion circuits 87A and 87B.

The subtraction circuit 88A and the addition circuit 88B output subtraction signals and addition signals of the output signals VX1 and VX2 output from the current-voltage conversion circuits 87A and 87B, respectively.

The division circuit 89 divides the subtraction signal output from the subtraction circuit 88A by the addition signal output from the addition circuit 88B,
The result of the division is output as an error signal VERX.

Here, as shown in FIG. 8, in the position detection sensor 68, when the light beam LA2 is condensed on the light receiving surface formed of the photoelectric conversion film, the current is applied to the resistance layer according to the condensing position of the light beam LA2. Flows, and the ratio of the output currents I1 and I2 changes.

As a result, the following equation is obtained through the division circuit 89. An error signal VERX in the X direction expressed by the following relationship can be obtained, and the condensing position of the light beam LA2 can be detected.

 Here, K1 represents a constant.

The Y direction position detection circuit outputs the output signal of the position detection sensor 68.
For IY1 and IY2, an addition / subtraction process is performed in the same manner to generate an error signal VERY in the Y direction.

Thereby, based on the error signals VERX and VERY,
The displacement of the light beam LA2 can be detected, and the irradiation position of the light beam LA1 can be corrected by driving the mirrors 56, 58 and the lens 58A based on the detection result.

By the way, in the position detection sensor 68, the light beam LA2
In addition, the incidence of the light beam LA1 reflected by the lenses 59A, 59B and the like cannot avoid the occurrence of measurement errors in the error signals VERX and XERY.

Therefore, in this embodiment, the light beam LA
After the transmission of 2 is interrupted and the measurement error is detected, the error signals VERX and VERY are corrected based on the detection result, thereby preventing a decrease in measurement accuracy.

That is, in the X direction, when the output signal components of the light receiving element 68 due to the reflected light are set as I1E and I2E, and the components due to the light beam LA2 are set as I1 and I1, the output signals IX1 and IY2 are represented by the following equation: IX1 = I1 + I1E 2) IX2 = I2 + I2E (3)

Substituting this into equation (1) gives the following equation After all, the output signals I1E and I2E of the position detection sensor 68 are detected in a state where the light beam LA2 is not incident, and the light beam
It can be seen that it is sufficient to subtract from the output signals IX1 and XI2 at the time of LA2 incidence.

Therefore, in the servo circuit 58, the light beam
The transmission of LA2 is interrupted, and the output voltages VE1 and VE2 of the current-voltage conversion circuits 87 and 87B are detected.

Further, between the current-voltage conversion circuits 87A and 87B and the subtraction circuit 88A and the addition circuit 88B, subtraction circuits 90A and 90B are interposed, respectively, so that the current-voltage conversion circuits 87A and 87 when the light beam LA2 is irradiated.
The detected output voltages VE1 and VE2 are subtracted from the B output signal, thereby correcting the error signal VERX.

In practice, the laser diode 51 is an automatic power control (APC).
The light beam LA1 is emitted so that the light intensity becomes constant by driving using an er control circuit.

Therefore, it is reflected by the transmission optical system 48 and the position detection sensor
The intensity of the light beam LA1 incident on 68 can be determined to be a substantially constant value regardless of whether or not the light beam LA2 is received.

Therefore, as in this embodiment, if the output signal of the position detection sensor 68 is detected without receiving the light beam LA2, and the error signals VERX and VERY are corrected based on the detection result,
Measurement accuracy can be improved.

Thus, even when the transmission distance increases and the intensity of the light beam LA2 decreases, highly accurate error signals VERX and VE can be used.
RY can be obtained, and the light beam is surely transmitted to the transmission target.
LA1 can be irradiated.

That is, when the control signal SC2 rises, the servo signal output circuit 91 amplifies the error signals VERX and VERY, and outputs the amplified error signals VERX and VERY as drive signals SX2 and SY2 via a low-pass filter circuit.

Accordingly, the servo circuit 58 drives the drive motors 60 and 61 to correct a gradual change in the light beam irradiation position.

Further, the servo signal output circuit 91 outputs the amplified error signal.
Drive signals SX1 and SY1 are generated from VERX and VERY, and the mirrors 56 and 57 are driven based on the drive signals SX1 and SY1, whereby the mirrors 56 and 57 are driven at a high speed to emit the light beam LA.
Correct the irradiation position of 1.

Further, at this time, the servo signal output circuit 91
The drive signals SX1 to SY2 are output so that the displacement center of the mirror 57 is located at the position of the displacement 0 of the mirrors 56 and 57.
The displacement centers of 56 and 57 are not displaced from the support center.

After the control signal SC2 falls, the servo signal output circuit 91 outputs control signals SX and SY from the system control circuit 77 in response to the operation of the operators 38A to 38D. , SY in response to the drive signals SX2 and SY2, whereby the operating elements 38A to 38D can be operated to adjust the irradiation position of the light beam LA1.

(G1-6-3) Servo stop control When demodulating and outputting the output signal of the light receiving element 64, the signal processing circuit 65 detects and outputs the signal level of the output signal.

Thus, the signal processing circuit 65 detects the amount of incident light on the light receiving element 64.

The comparison circuit 94 obtains a comparison result between the detection result of the signal processing circuit 65 and a predetermined comparison reference at a predetermined cycle, and outputs the comparison result to the servo signal output circuit 91.

Accordingly, the servo signal output circuit 91 detects a decrease in the light amount of the light beam LA2, and stops outputting the drive signals SX1 to SY2 when the light amount of the light beam LA2 decreases below a predetermined value determined by the comparison reference.

As a result, when the light amount of the light beam LA2 decreases and the accuracy of the error signals VERX and VERY decreases, the servo signal output circuit 91 controls to stop the servo operation and effectively avoids a malfunction of the entire servo circuit.

As a result, even if the light amount of the light beam LA2 is reduced,
The irradiation position of the light beam LA1 can be held so as not to be displaced in a direction completely unrelated to the transmission object, and the servo operation can be reliably performed immediately after the light amount of the light beam LA2 returns to a predetermined value or more.

Therefore, regarding the irradiation position of the light beam LA1, the light beam L
The readjustment operation when the light amount of A2 is reduced can be omitted, and the usability of the optical space transmission device 30 can be improved accordingly.

The incident light amount detection circuit 96 outputs the output signal of the position detection sensor 68.
IX1 to IY2 are added to detect the incident light amount of the light beam LA2 incident on the position detection sensor 68.

Here, as shown by the symbol T in FIG. 9, the center wavelength of the pass band is
A narrow-band filter 67 set to have a wavelength of 2 is arranged.

The comparison circuit 97 obtains a comparison result between the detection result of the incident light amount detection circuit 96 and the detection result of the incident light amount of the signal processing circuit 65, and when the following equation VS ≦ α · VD (5), the servo signal output circuit 91 The comparison result is output, and the output of the drive signals SX1 to SY2 is thereby controlled to stop.

 Here, α is a predetermined constant.

That is, as shown in FIG. 10, by disposing the narrow-band filter 67 that passes the light beam LA2 in front of the position detection sensor 68, when sunlight with a wide band enters the optical space transmission device main body 34, The incident light amount of the light receiving element 68 is significantly increased as compared with the incident light amount of the position detection sensor 64.

Therefore, if the comparison result of the incident light amounts of the light receiving element 68 and the position detection sensor 64 is obtained, it can be determined whether or not the increase in the incident light amount is due to sunlight.

Thus, the optical space transmission apparatus 30 stops the servo operation based on the expression (5), and stops and controls the servo operation when the accuracy of the error signals VERX and VERY decreases due to the incidence of sunlight.

Thus, even when sunlight is incident, the optical space transmission device 30 holds the irradiation position of the light beam LA1 so as not to be displaced in a direction completely unrelated to the transmission target, and ensures that immediately after the sunlight has stopped entering. The servo operation can be performed.

Therefore, the operation of adjusting the irradiation position of the light beam LA1 when sunlight is incident can be omitted, and the usability of the optical space transmission device can be improved accordingly.

(G-1-4) Configuration of Mirror As shown in FIG. 11, the mirrors 56 and 57 are supported by the lens barrel of the main body of the transmission optical system 48 via a predetermined holding member.

That is, the bearing bases 100A and 100B pivotally support the rotating member 101 from both sides, thereby holding the rotating member 101 rotatably as shown by the arrow h.

As shown in FIG. 12, the rotating member 101 holds the mirror supporting member 102 and the vibration damping member 103 so as to sandwich them.

Here, the vibration damping member 103 is made of a rubber-like sheet material that absorbs vibration, and is formed by cutting the sheet material into a predetermined shape.

The mirror support member 102 is formed of a bimorph plate made of a piezoelectric element, and its tip is displaced according to an applied voltage as shown by an arrow i.

The distal end of the mirror support member 102 is inserted and bonded into the U-shaped groove of the bonding table 104, and the mirror 56 (57) is bonded through the bonding table 104.
Hold.

As a result, in the optical space transmission device main body 34, the drive signals SX1 and SY1 are applied to the mirror support member 102, and the mirror 56 (5
7) is displaced, and the irradiation position of the light beam LA1 is corrected by the displacement of the mirror 56 (57).

The bearing bases 100A and 100B are rotated by screwing screws 105A and 105B into screw holes provided in the bearing portion.
101 can be fixed, so that the mounting positions of the mirrors 56 and 57 can be adjusted.

Thus, by displacing the mirrors 56 and 57 using the balmorph plate to correct the irradiation position of the light beam LA1, the irradiation position of the light beam LA1 can be corrected with a simple configuration.

Further, the response speed can be improved as compared with the case where a galvanomirror is used, and the information can be transmitted more reliably.

The vibration damping member 103 is made to adhere to the entire surface of the mirror supporting member 102.

That is, when the bimorph plate is used as described above, there is a problem that the resonance frequency of the bimorph plate is low.

As shown in FIGS. 13 and 14, simply the bimorph plate 10
If only 2 supports the mirror, 14
A resonance point of [dB] appears (Fig. 14 (A)), and the maximum is-
The phase changes by 190 degrees (FIG. 14 (B)).

Therefore, the gain of the servo circuit 58 cannot be increased, and it becomes difficult to improve the following speed.

On the other hand, as shown in FIGS. 15 and 16, when the rubber-like sheet member 106 is attached to the back of the bimorph plate 102, the resonance frequency increases to 95 [Hz] (FIG. 16 (A)). ),
The phase delay also decreases to -172 degrees (FIG. 16 (B)).

Further, as shown in FIG. 17, when the vibration damping member 103 is attached to the bimorph plate 102 and held together so as to be sandwiched by the rotating member 101, the resonance frequency becomes 160 [H] as shown in FIG.
z] (FIG. 17 (A)), and the phase delay can be reduced to -130 degrees (FIG. 17 (B)).

Accordingly, the frequency characteristics of the bimorph plate 102 can be improved, and the configuration of the servo circuit 58 can be simplified accordingly.

Further, the irradiation position of the light beam LA1 can be corrected by following the vibration or the like at a high speed, and the response speed can be improved accordingly.

Further, in this embodiment, the bonding table 104 holds the mirror 56 (57) at a predetermined distance D from the bimorph plate 102.

That is, as shown in FIG. 18, when the bimorph plate 102 and the mirror 56 (57) are arranged close to each other, the bimorph plate 10
When 2 is displaced toward the mirror 56 (57), the lower end of the mirror 56 (57) may come into contact with the bimorph plate 102, and the displacement of the mirror 56 (57) may be limited.

Therefore, in the optical space transmission device 30, the bimorph plate 10
By holding the mirror 56 (57) at a predetermined distance D from 2, the irradiation position of the light beam LA1 can be surely corrected even when the bimorph plate 102 is largely displaced.

(G1-7) System Control Circuit The system control circuit 77 is composed of an arithmetic processing circuit and controls the entire optical space transmission device 30.

That is, the system control circuit 77 outputs a control signal SC2 to the servo circuit 58 when power is supplied from the power supply device 31,
The optical space transmission device main body 34 is started up in a servo state.

When the initializing switch 37 is turned on in this state, the system control circuit 77 outputs the control signal SC1 to drive the motors 60 and 61, and sets the lens 59A to the position of the rotation center.

Thereby, the system control circuit 77 sets the optical space transmission device 30 to an initial state for adjusting the irradiation position of the light beam LA1.

That is, when the operators 38A to 38D are turned on, the system control circuit 77 outputs the control signals SX and SY to the servo circuit 58 in response to the operations of the operators 38A to 38D, and the lens 59A
Is rotated.

At this time, when the monitor switch 41 is turned on, the system control circuit 77 outputs the control signal SC1 to display the display screen 36.
Is displayed, and the magnification of the imaging optical system 70 is switched in response to the ON operation of the zoom operator 42.

Therefore, the user is required to initialize the switch 37.
After turning on, the operation position of the light beam LA1 can be easily adjusted by operating the operating elements 38A to 38D, and by turning on the servo switch 39 after the adjustment, the light beam LA1 is transmitted to the transmission target. Can be reliably irradiated.

On the other hand, when the supply of power is interrupted, a predetermined locking mechanism is operated, whereby the lens 59A is held at a position immediately before the power is turned off.

Thus, in the system control circuit 77, for example, even when the battery is replaced by interrupting the communication, the communication can be quickly resumed after the replacement.

That is, by turning the lens 59A to the initial state each time the power is turned on, the initialization switch 37 can be omitted, and the number of operators can be reduced accordingly.

However, in this case, even when the battery is simply replaced, the irradiation position of the light beam LA1 is unnecessarily initialized each time, and the irradiation position of the light beam LA1 needs to be adjusted again.

Therefore, the initialization switch 37 is used as in this embodiment.
Separately, and when the power is turned on, by starting up the optical space transmission device main body 34 so as to perform a servo operation,
The servo state can be released only when necessary, and the adjustment work at power-on can be omitted if necessary.

Therefore, the usability of the optical space transmission device 30 can be improved accordingly.

Thus, in the optical space transmission device 34, when the communication is interrupted, the communication can be resumed immediately by starting the supply of power.

When the system control circuit 77 rises to the servo state,
The light emitting element 40A is turned on.

In this state, based on the error signals VERX and VERY of the servo circuit 58, when the light beam LA2 is condensed within a predetermined range on the light receiving surface of the position detection sensor 68, the system control circuit 77 determines that the state is a servo lock state. Then, the light emitting element 40B is turned on.

Therefore, when the light emitting element 40A is turned on and the light emitting element 40B is not turned on, it can be determined that the irradiation position of the light beam LA1 cannot be corrected.

As a result, the user operates the initialization switch 37 and the operators 38A to 38D again to operate the light beam LA1.
After re-adjusting the irradiation position, turn on the servo switch 39 to ensure that the light beam
LA1 can be irradiated.

Further, the system control circuit 77 ignores the on-operations even if the controls 38A to 38D are turned on as long as the initialization switch 37 is not on-operated, thereby effectively avoiding a user's erroneous operation. I have.

If the amount of movement of the lens 59A is too large, for example, a case may occur where the servo operation can follow a large displacement on the left side but cannot follow a large displacement on the right side.

Therefore, the system control circuit 77 uses the limit switches 108 and 109 provided on the rotation shafts of the motors 60 and 61 to control the lens.
The moving amount of 59A is detected, and when the moving amount is equal to or more than a predetermined value, the buzzer circuit 116 is driven.

Thus, the system control circuit 77 emits a buzzer sound when the movement amount becomes equal to or more than the predetermined value, and draws the user's attention.

(G2) Operation of Embodiment The light beam LA1 of the predetermined polarization plane W1 emitted from the laser diode 51 (FIG. 2) is converted into a parallel light beam by the lens 52, then passes through the polarizing prism 53, and passes through the lens 54 and the lens 54. lens
The light is reflected by mirrors 56 and 57 via 55.

Here, the light beam LA1 reflected by the mirrors 56 and 57 is
After passing through the half mirror 69, it is transmitted to the transmission target via the lenses 59A and 59B.

At this time, the bimorph plate 102 (FIG. 11) is displaced by the drive signals SX1 and SY1 output from the servo circuit 58, and the mirrors 56 and 57 held at the tips of the bimorph plate 102 are indicated by arrows a and b, respectively. The irradiation position of the light beam LA1 is corrected by a small angular displacement in the horizontal and vertical directions.

On the other hand, the drive signal SX output from the servo circuit 58
Based on 2 and SY2, the motors 60 and 61 move the lens 59A up, down, left and right as indicated by arrows c and d, and the irradiation position of the light beam LA1 is roughly corrected.

As a result, in the optical space transmission device main body 34, the mirror
Even if the optical space transmission device main body vibrates due to wind or the like by moving the lenses 56 and 57 and the lens 59A, the light beam LA1 is reliably irradiated to the transmission target.

The light beam LA2 arriving from the transmission target is received by the lens 59B, reverses the optical path of the light beam LA1, and enters the polarizing prism 53.

Here, the light beam LA2 is emitted from the transmission target such that the polarization plane W2 is orthogonal to the polarization plane W1 of the light beam LA1, so that the light beam LA2 is reflected by the polarizing prism 53 and then enters the half mirror 62. .

Here, a part of the light beam LA2 is condensed on the light receiving element 64 via the lens 63, whereby the information signal S2 transmitted from the transmission target can be received.

Further, the remaining part of the light beam LA2 is condensed on the light receiving surface of the position detection sensor 68 via the filter 66 and the condensing lens 67, whereby the emission position of the light beam LA2 with respect to the optical space transmission device main body 34 is determined. It can be detected with high accuracy.

The light beam LA1 is partially separated when passing through the half mirror 69, and is guided to the corner cube prism 71 via the shutter 75.

Here, the light beam LA1 has its optical path turned back in parallel, and is guided to the imaging optical system 70 via the shutter 75 and the half mirror 69.

At this time, the observation light L1 traveling from the scenery around the transmission target to the optical space transmission device 30 is received via the lenses 59B and 59A, reflected by the half mirror 69, and guided to the imaging optical system.

Thus, the irradiation position of the light beam LA1 can be confirmed via the imaging optical system 70.

At this time, in the imaging optical system 70, the zoom drive circuit 74
The optical space transmission device body 34 is roughly driven at a low magnification by the light beam LA.
After adjusting the irradiation position of No. 1, the irradiation position is adjusted by sequentially increasing the magnification, and the servo circuit 58 is operated within a predetermined range, so that the irradiation position of the light beam LA1 can be easily adjusted.

The output signals IX1 to IY2 (FIGS. 6 and 7) of the position detection sensor 68 are input to the X-direction and Y-direction position detection circuits 86A and 86B of the servo circuit 58, where they are subjected to addition / subtraction processing to output error signals VERX and VBERY is detected.

At this time, in the output signals IX1 to IY2 of the position detection sensor 68, after the signal level is detected while the transmission of the light beam LA2 is interrupted, the detection result is subtracted from the signal level during the transmission of the light beam LA2. Thereby, the measurement error of the error signals VERX and VERY can be reduced.

Thus, even when the transmission distance increases and the intensity of the light beam LA2 decreases, highly accurate error signals VERX and VE can be used.
You can get RY.

The error signals VERX and VBRY are output from the servo signal output circuit.
91, whereby the corresponding error signals VERX and VERY
, The drive motors 60 and 61 and the mirrors 56 and 57 are driven, and the irradiation position of the light beam LA1 is corrected.

Further, the output signals IX1 to IY2 of the position detection sensor 68 are input to the incident light amount detection circuit 96, where the signal level is detected, whereby the incident light amount of the position detection sensor 68 is detected.

The detection result is output from the comparison circuit 97 to the signal processing circuit.
The detection result of the incident light amount of the light receiving element 64 output from 65 and the comparison result are obtained.

At this time, the position detection sensor 68 can detect the incidence of sunlight based on the comparison result of the comparison circuit 97 by receiving the light beam LA2 via the narrow band filter 66.

This makes it possible to effectively control the servo operation to stop and prevent a malfunction of the entire servo circuit, so that even when sunlight is incident, the irradiation position of the light beam LA1 is not displaced in a direction completely unrelated to the transmission target. And the servo operation can be performed immediately after sunlight stops being incident.

Therefore, the readjustment of the light beam irradiation position can be omitted,
As a result, the usability of the optical space transmission device can be improved.

The comparison result of the incident light amount detection result of the light receiving element 64 is obtained by a comparison circuit 94 with a predetermined comparison reference.

As a result, the servo signal output circuit 91 detects a decrease in the light amount of the light beam LA2, and controls the stop of the servo operation based on the detection result, thereby effectively avoiding the malfunction of the entire servo circuit.

As a result, the light amount of the light beam LA2 decreases and the error signal V
When the accuracy of ERX and VERY decreases, the servo operation can be stopped and controlled, and malfunction of the entire servo circuit can be effectively avoided.

Therefore, even when the light intensity of the light beam LA2 decreases, the irradiation position of the light beam LA1 can be held so as not to be displaced in a direction completely unrelated to the transmission target, and the servo operation is started immediately after the light intensity of the light beam LA2 is restored. can do.

Therefore, the readjustment of the light beam irradiation position can be omitted,
As a result, the usability of the optical space transmission device can be improved.

(G3) Effects of Embodiment According to the above configuration, the light receiving element 64 and the position detection sensor
By obtaining comparison results based on 68 detection results,
It is possible to detect a reduction in the incident light amount of the light beam LA2 and the incidence of sunlight, and to stop and control the servo operation based on the detection result, thereby effectively avoiding a malfunction of the entire servo circuit.

As a result, even when the light amount of the light beam LA2 is reduced or sunlight enters, the irradiation position of the light beam LA1 can be held so as not to be displaced in a direction completely unrelated to the transmission target, and the light amount of the light beam LA2 is restored. The servo operation can be started immediately after the start and immediately after the sunlight stops.

Thus, readjustment of the light beam irradiation position can be omitted,
As a result, the usability of the optical space transmission device can be improved.

(G4) Other Embodiments In the above-described embodiment, the case where the lens 59A is rotated as the position correcting means and the bimorph plate 102 is displaced has been described. However, the present invention is not limited to this. Instead of driving a mirror with a motor,
Various position correction means can be widely applied.

Further, in the above-described embodiment, a case has been described in which the light amount decrease of the light beam LA2 is detected based on the output signal of the light receiving element 64.However, the present invention is not limited to this, and based on the output signal of the position detection sensor The present invention can be widely applied to the case of detecting, and the case of separately providing a light receiving element.

Further, in the above-described embodiment, the case where the filter of the predetermined band is arranged on the front surface of the position detection sensor 68 has been described. However, the present invention is not limited to this, and the filter may be arranged on the front surface of the light receiving element 64.

When a light receiving element is additionally provided, a filter configured to block the light beam LA2 may be provided on the front surface of the light receiving element.

This makes it possible to easily detect the incidence of sunlight based on the output signal of the light receiving element.

Furthermore, in the above-described embodiment, a case has been described in which the servo operation is stopped and controlled when sunlight enters, but the present invention is not limited to this, and a shutter or the like is provided on the optical path of the transmission optical system 48, and the light receiving element 64 , 68, etc., the shutter may block incident sunlight.

H Effects of the Invention As described above, according to the present invention, the control of the stop of the servo circuit and the incidence of the incident light are detected as necessary by detecting the decrease in the amount of the received light beam and the incidence of sunlight based on the output signal of the light receiving element. It is possible to obtain an optical space transmission device that can block light and the like, thereby improving usability.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an optical space transmission apparatus according to an embodiment of the present invention, FIG. 2 is a schematic diagram showing the transmission optical system, FIG. 3 is a perspective view showing a collimator scope, and FIG. FIG. 5 is a schematic diagram for explaining the polarization plane correction, FIG. 6 is a block diagram showing a servo circuit, FIG. 7 is a block diagram showing a position detecting circuit, and FIG. 8 is a position diagram. FIG. 9 is a schematic diagram showing the characteristics of the filter, FIG. 10 is a characteristic curve diagram showing the relationship between the incident light, FIG. 11 is a perspective view showing the configuration of the mirror, and FIG. Is a cross-sectional view showing a cross section of the mirror, FIG. 13 is a cross-sectional view for explaining a method of supporting the mirror, FIG. 14 is a characteristic curve diagram showing its frequency characteristics, and FIG.
FIG. 15 is a cross-sectional view for explaining another method of supporting the mirror, and FIG.
16 is a characteristic curve diagram showing the frequency characteristic, FIG. 17 is a characteristic curve diagram showing the frequency characteristic according to the embodiment, FIG. 18 is a side view showing another embodiment, and FIG. 19 is a conventional optical space transmission device. FIG. 1, 30 ... optical space transmission device, 2, 51 ... laser diode, 4, 12, 16, 18, 20, 52, 54, 55, 59A, 59B, 63,
67 ... Lens, 6,53 ... Polarizing prism, 8,62,69 ...
... half mirror, 56, 57 ... mirror, 60, 61 ... motor, 64 ... light receiving element, 65 ... signal processing circuit, 68 ... position detection sensor, 86A, 86B ... position detection circuit, 91 ... Servo signal output circuit, 94, 97 ... comparison circuit, 96 ... incident light amount detection circuit.

Claims (2)

(57) [Claims] 1. A transmission light beam having a predetermined polarization plane modulated by a predetermined information signal is transmitted to a transmission / reception apparatus arranged at a predetermined distance, and a reception light beam having a predetermined polarization plane transmitted from the transmission / reception apparatus is provided. A spatial light transmission for transmitting the information signal to the transmitting / receiving device via the transmitting light beam by receiving the beam, and receiving a predetermined information signal transmitted from the transmitting / receiving device via the receiving light beam. In the apparatus, a light source that emits the transmission light beam, and a polarized light beam that reflects or transmits the transmission light beam emitted from the light source and that transmits or reflects the reception light beam opposite to the transmission light beam Separating means for transmitting the transmitting light beam obtained through the polarized light beam separating means to the transmitting and receiving device, and arriving from the transmitting and receiving device. An optical system that guides a received light beam to the polarized light beam separating means; a light receiving unit that receives the received light beam obtained through the polarized light beam separating means; and a transmission based on an output signal of the light receiving unit. An irradiation position correcting means for correcting an irradiation position of the light beam; detecting an incident light amount of the reception light beam based on an output signal of the light receiving unit; and detecting the irradiation position correction when the incident light amount falls below a predetermined value. Control means for stopping and controlling the operation of the means. 2. A transmission light beam having a predetermined polarization plane modulated by a predetermined information signal is transmitted to a transmission / reception apparatus which is arranged at a predetermined distance, and a reception light beam having a predetermined polarization plane transmitted from the transmission / reception apparatus. A spatial light transmission for transmitting the information signal to the transmitting / receiving device via the transmitting light beam by receiving the beam and receiving a predetermined information signal transmitted from the transmitting / receiving device via the receiving light beam. In the apparatus, a light source that emits the transmission light beam, and a polarized light beam that reflects or transmits the transmission light beam emitted from the light source and that transmits or reflects the reception light beam opposite to the transmission light beam Separating means for transmitting the transmitting light beam obtained through the polarized light beam separating means to the transmitting and receiving device, and arriving from the transmitting and receiving device. An optical system that guides a received light beam to the polarized light beam separating means; a light receiving section that receives the received light beam obtained through the polarized light beam separating means via a predetermined filter; and an output signal of the light receiving section And a sunlight detection circuit that detects the incidence of sunlight on the optical system based on the following.