JP2687437B2 - Optical space transmission equipment - Google Patents

Description

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

A Industrial field B Outline of the invention C Prior art D Problems to be solved by the invention E Means for solving problems (Figs. 3 to 5) F action (Figs. 3 to 5) Fig. G Example (Figs. 1 to 15) H Effect of the invention A Industrial field of application The present invention relates to an optical space transmission device, for example, for transmitting and receiving information to and from each other via a spatially transmitting light beam. It is suitable to be applied to the optical space transmission device.

B. Summary of the Invention The present invention provides a simple optical space transmission device by folding back an emission light beam sent from a transmission device in parallel and guiding it to an imaging device alternately with an incident light beam coming from the reception device side. The configuration makes it possible to detect the deviation of the optical axis.

C Conventional Technology Conventionally, in this type of optical space transmission device, the direction of the optical axis of the emission light beam is adjusted so that the emission light beam sent from the transmission device irradiates the reception device with certainty. (Hereinafter, referred to as optical axis alignment), it is possible to reliably transmit information between the transmitting and receiving devices.

That is, at the time of installation, the receiving device side detects the irradiation position of the light beam for emission to obtain an error signal, which is transmitted to the transmitting device side for optical axis alignment.

On the other hand, after installation, if you always send an error signal to align the optical axis (that is, align the optical axis by the servo), it is possible to ensure that the optical axis will vibrate due to wind or the like. Information can be transmitted.

D Problem to be Solved by the Invention However, when the optical axes are aligned in this way, the error signal must be transmitted to the transmitter side, and a line for error signal transmission is required.

In this case, for example, if a dedicated line such as a telephone line is used, a telephone line or the like has to be installed between the transmitting and receiving devices, which complicates the entire configuration and only needs to install the transmitting and receiving device on the roof of a building. Therefore, the advantage of the optical space transmission device that information can be easily transmitted is lost.

As one method for solving this problem, there is a method of transmitting an error signal by irradiating a light beam from the receiving device side to the transmitting device side.

However, in this way, a transmitter for irradiating the light beam from the receiver side to the transmitter side, a light modulator for modulating the light beam with an error signal, a demodulator for the same, etc. are required separately. There is a problem that the configuration of the entire space transmission device becomes complicated.

Further, when the optical axes are aligned by servo, it is necessary to constantly operate the light beam irradiation position on the receiving device side and send an error signal from the receiving device side.

Also, in order to obtain an error signal on the receiver side at the time of installation,
It is necessary to spread the light beam emitted from the transmitting device to some extent, and there is a problem that the amount of light of this spectral beam must be increased.

The present invention has been made in consideration of the above points, and intends to propose an optical space transmission device that can solve the conventional problems all at once and can perform optical axis alignment with a simple configuration as a whole. .

E Means for Solving the Problems In order to solve the above problems, in the present invention, by transmitting an emission light beam LA1 modulated with an information signal to a receiving device, information is emitted via the emission light beam LA1. Optical space transmission device 1 adapted to transmit a signal to a receiving device
In the imaging device 45, a part of the emission light beam LA1 is folded back in a direction parallel to and opposite to the optical axis of the emission light beam LA1 toward the reception device, and the emission light beam LA1 is received by the reception device. Optical path turning-back means 46 obtained as an irradiation position light beam representing the irradiation position SP1, an irradiation position light beam obtained from the optical path turning means 46, and an incident light beam LA4 coming from the receiving device side in the opposite direction to the emission light beam LA1. Alternately, based on the video signal obtained from the shutter device 55, 56 and the image pickup device 45, which introduces the image pickup device 45 alternately, the irradiation position S on the picked-up image of the emission light beam LA1 sent to the receiving device.
Position detecting means 64, 65 for detecting P1 and the installation position SP2 on the captured image of the receiving device are provided.

F action: The emitted light beam LA1 is folded back in parallel with its optical axis L, and is switched by the shutter means 55, 56 alternately with the incident light beam coming from the receiving device side.
If it is introduced into 45, the difference between the installation position SP2 of the receiving device and the irradiation position SP1 of the emission light beam LA1 can be easily detected on the transmission side by distinguishing the two light beams.

G. Embodiment An embodiment in which the present invention is applied to a bidirectional optical space transmission device will be described in detail below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a transmitter of the optical free space transmission apparatus as a whole, which is housed in a housing 2 and installed, for example, on the roof of a building.

An operation panel 2A is provided on the front surface of the housing 2, and on the operation panel 2A, a screen switching switch 4A, a power switch 4B of the display device 3, and a horizontal and vertical optical axis alignment are provided together with the display device 3. Switches 4C and 4D, gain adjusting operators 5A and 5B for optical axis alignment by a servo, and a display unit 6 for displaying the light beam irradiation position and the like.

Further, on the operation panel 2A, there is provided a receiving section 9 for receiving the control signal transmitted from the remote commander 8, so that the remote control can be performed even if the operators 4A-5B on the operation panel 2A are not directly operated. The commander 8 can be used to remotely control the transmitter 1.

Further, in the operation panel 2A, the display device 3, the operation device
A transparent cover 10 is attached via screws 11 so as to cover 4A to 5B and the display unit 6, so that after the cover 10 is attached, the operators 4A to 5B cannot be directly operated. Has been made.

Therefore, when the transmitter 1 is installed, the remote commander 8 is remotely operated to align the optical axes.

In fact, in the optical free space transmission apparatus, the emission light beam LA1 is sent toward the reception apparatus far away from the transmission apparatus 1. Therefore, if the transmission apparatus 1 vibrates even slightly, the emission light beam LA1 The irradiation position of changes greatly.

Therefore, the operator on the operation panel 2A for aligning the optical axis
The optical axis of the emission light beam LA1 may change just by touching 4A to 5B, in which case there is a problem that an error occurs in the optical axis alignment.

Therefore, in this embodiment, an error is not caused in the optical axis alignment by remotely operating the remote commander 8 to align the optical axes instead of operating the operators 4A to 5B on the operation panel 2A. ing.

Further, by attaching the cover 10 so that the operators 4A to 5B cannot be directly operated, the display device 3, the operators 4A to 5B, and the display unit 6 are effectively protected from rain, dust, and the like. You can

On the other hand, as shown in FIG. 2, a light beam irradiation optical system 20 is provided inside the housing 2 so that the emission direction of the light beam LA1 can be adjusted.

That is, the U-shaped mount 21 fixed to the housing 2 is configured to support the annular holding member 22 by the shaft 24 via the support member 23, and the shaft 24 and the light beam irradiation optical system. It is arranged so that the optical axis L of the light beam LA1 emitted from 20 is orthogonal (the axis 24 extends in the horizontal direction).

The holding member 22 includes a gear 25 having a shaft 24 as a central axis of rotation, and the gear 25 meshes with the gear 27.

Accordingly, the gear is fixed via the motor 26 fixed to the mount 21.
By rotating 27, the holding member 22 can be rotated in the direction indicated by the arrow a with the shaft 24 as the rotation center axis.

On the other hand, the holding member 22 is configured such that the cylindrical lens holding member 30 is axially supported by the shaft 32 via the support member 31, and the shaft 32 and the shaft 24 and the optical axis L are orthogonal to each other ( That is, the shaft 32 extends vertically.

Like the holding member 22, the lens holding member 30 includes a gear 33 having a shaft 32 as a rotation center axis, and the gear 33 is a gear.
It is designed to mesh with 34.

Accordingly, by rotating the gear 34 through the motor 35 fixed to the holding member 22, the lens holding member 30
Can be rotated in the direction indicated by the arrow b with the shaft 32 as the central axis of rotation.

On the other hand, as shown in FIG.
Inside the cylinder, a slide table 40 is provided which is equipped with a laser light source 41 and is supported by a guide 38, and when a motor 39 rotates, the laser table 41 is moved in the central axis direction c of the lens holding member 30. The light source 41 is adapted to move.

In addition, the lens holding member 30 has a large-diameter lens inside.
42 is provided, the light beam LA emitted from the laser light source 41
1 is converted into parallel rays via the lens 42 and sent to the receiving device side.

Although illustration is omitted, a light receiving element is arranged around the laser light source 41, and the light beam sent from the receiving device is focused on the light receiving element.

Thus, by driving the motors 26 and 35, the optical axis L of the light beam LA1 can be changed in the vertical and horizontal directions, and thus the emission direction of the light beam LA1 can be adjusted to align the optical axes. .

On the other hand, by driving the motor 39 to move the laser light source 41 back and forth, the light beam LA1 sent from the transmitter 1 can be adjusted into parallel rays.

Incidentally, the laser light source 41 emits the light beam LA1 modulated by a predetermined information signal, and thereby transmits the information signal to the receiving device.

Further, the light receiving element outputs the output signal to a predetermined signal processing circuit so that desired information sent from the receiving device can be demodulated by the transmitting device 1.

On the other hand, the television camera
45 is attached, and coarse adjustment is performed so that the optical axis of the television camera 45 and the optical axis of the light beam LA1 roughly match.

The image captured by the television camera 45 is displayed on the display device 3 by switching the screen switching switch 4A, whereby the worker is irradiated with the light beam LA1 via the display device 3. You can check the approximate position.

Thus, the direction of the optical axis L of the light beam LA1 can be roughly adjusted, and the receiver side can be observed.

Further, a collimating scope 46 is provided inside the housing 2 in front of the lens 42 and the television camera 45,
A part of the light beam LA1 is divided into spectra and the optical axis L of the light beam LA1 is divided.
In parallel with this, an irradiation position light beam representing the irradiation position of the light beam LA1 with respect to the receiving device is guided to the television camera 45.

That is, the collimator scope 46 receives a part of the light beam LA1 by the half mirror 48 arranged at an angle of about 45 degrees with respect to the optical axis L, and thereby the light beam L1.
A1 goes straight, and the reflected light beam goes in the direction of about 90 degrees.
It is designed to reflect LA2.

On the other hand, the half mirror 46 is held at a high degree of parallelism with respect to the half mirror 48, transmits the reflected light beam LA2 of the half mirror 48, and guides it to the corner cube prism 50.

The corner cube prism 50 is arranged so that the reflected light beam LA2 is incident on its incident surface 50A, whereby the reflected light beam LA3 whose optical axis is parallel to the reflected light beam LA2 is generated. The light is reflected by the prism 50 and is incident on the half mirror 49.

Therefore, in the half mirror 49, the reflected light beam
LA3 is reflected at an angle of almost 90 degrees, and its reflected light beam LA4
Is incident on the television camera 45 via the lens 52.

Thus, the image of the laser light source 41 can be observed based on the reflected light beam LA4 incident on the television camera 45.

Further, in the collimator scope 46, a window 53 is provided on the front surface of the television camera 45, whereby a laser light source is provided.
The image of 41 and the image of the receiver side can be observed at the same time.

Thus, the half mirrors 48 and 49 and the corner cube prism 50 are parallel to the optical axis of the emitted light beam LA1.
While the optical path folding optical system that returns the light beam LA1 is configured, the television camera 45 configures the reflected light beam LA4 that is folded back by the optical path folding optical system and an imaging device that captures an image on the receiving device side.

At this time, by holding the half mirrors 48 and 49 with a high degree of parallelism, even when the collimating scope 46 is arranged inclined with respect to the optical axis L of the light beam LA1 as shown by an arrow e (that is, half Even if the mirror 48 is not placed at an exact 45 degree angle with respect to the lens 42), a reflected light beam LA4 parallel to the optical axis of the light beam LA1 can be obtained.

Further, the reflected light beam LA2 from the half mirror 48 is folded back via the corner cube prism 50, so that the collimating scope 46 is reflected by the light beam LA as shown by an arrow f.
Even when they are arranged with a twist with respect to the optical axis of 1, the reflected light beam LA4 parallel to the optical axis of the light beam LA1 can be obtained.

Therefore, in the television camera 45, the light beam LA
It is possible to obtain the reflected light LA4 emitted from the irradiation position of 1, and as a result, as shown in FIG.
An image similar to that in the case where is placed at the irradiation position of the light beam LA1 can be observed by superimposing it on the image on the receiving device side.

Furthermore, by only holding the half mirrors 48 and 49 with a high degree of parallelism, the reflected light beam LA4 parallel to the optical axis of the light beam LA1 can be obtained.
Since it can be guided to the television camera 45, the irradiation position of the light beam LA1 can be reliably detected even if the optical axis of the television camera 45 is attached to be displaced from the optical axis of the light beam LA1. You can

In fact, in this type of optical system, the half mirror 48,
The surface accuracy of the 49 and the corner cube prism 50 can be set to a high accuracy of 10 seconds or less as a whole.

In this case, if the accuracy of 10 seconds goes wrong, 48 at a position 1 [km] away
Since the error of [mm] occurs, the irradiation position of the light beam LA1 can be detected in a practically sufficient range.

Thus, on the transmitter side, the light beam can be easily and accurately
The irradiation position of LA1 can be detected.

Further, the collimating scope 46 is a half mirror 48 and
49 and between the half mirror 49 and the window 53 are provided with shutters 55 and 56 composed of liquid crystal optical elements, and by alternately opening and closing the shutters 55 and 56, the image of the laser light source 41 and the image of the receiving device side are alternated. It is designed to be imaged.

That is, as shown in FIG. 5 and FIG. 6, a television vertical output from the camera 45 sync signal S _V (FIG. 6 (A)) receiving the counter circuit 60, the vertical sync signal S _V
Divided signal S whose signal level rises at twice the cycle of
_The shutter 56 is driven at _2V (FIG. 6 (B)).

Further, the frequency-divided signal S obtained via the inverting amplifier circuit 61
In dividing the inverted signal S _21V of _2V (Fig. 6 C) to drive the shutter 55, thereby opening and closing alternately shutters 55 and 56 in the period of the vertical synchronizing signal S _V.

As a result, during the period T1 when the signal level of the frequency division inversion signal S _2V rises, only the image on the receiving device side can be picked up via the television camera 45, and by switching the screen switching switch 4A, As shown in the figure, the image on the side of the receiving device can be displayed on the display screen of the display device 3.

By the way, the receiving device is configured to irradiate the transmitting device 1 with a light beam having a predetermined spread instead of the light beam modulated by the information signal at the time of installation. , A bright and shining optical spot SP2 (Fig. 7) is provided at the position of the receiving device.

Therefore, if the position of the optical spot SP2 is detected based on the video signal obtained through the television camera 45 during the period T1, the installation position of the receiving device can be detected.

On the other hand, only the laser light source 41 can be imaged through the television camera 45 during the period T2 when the signal level of the frequency division inversion signal S _21V rises, and as a result, as shown in FIG. Laser light source on the display screen of 3
41 images can be obtained as a bright and shining light spot SP1.

Therefore, during the period T2, if the position of the light spot SP1 is detected based on the video signal obtained via the television camera 45, the irradiation position of the light beam LA1 can be detected.

Thus, if the positions of the optical spots are detected during the periods T1 and T2, it is only necessary to provide a light source on the receiving device side.
The irradiation position of the light beam LA1 and the position of the reception device can be detected on the transmitter side, and the optical axis of the light beam LA1 can be aligned based on the detection result, whereby the optical axis can be aligned with a simple configuration as a whole. .

Actually, as shown in FIG. 4, when the image of the receiving device side and the image of the laser light source 41 are simultaneously captured, the optical spots SP1 and S
Even if the position of P2 can be detected, there is a problem that it is difficult to identify which optical spot SP1 or SP2 is the optical beam LA1 or the optical spot of the receiving device.

Therefore, in this case, it is not possible to determine in which direction the optical axis L of the light beam LA1 should be corrected.
There is a problem that it is difficult to align the optical axes.

As a method of solving this problem, a method of blinking the light beam LA1 may be considered, but the light spot SP1 or S
When P2 is close, the optical spots SP1 and SP2 are imaged as if they were one optical spot and are virtually indistinguishable.

Therefore, as in this embodiment, the shutters 55 and 56 are alternately opened and closed so that the light beam LA4 folded by the collimating scope 46 and the light beam emitted from the receiving device are alternately guided to the television camera 45. By doing so, the optical spots SP1 and SP2 can be reliably identified, and the optical axis alignment direction can be detected.

Thus, the shutters 55 and 56, the counter circuit 60, and the inverting amplifier circuit 61 constitute a shutter means for alternately switching the folded light beam LA4 and the light beam sent from the receiving device side and guiding it to the television camera 45. .

Thus, as shown in FIG. 9, a raster scanning video signal S _E (FIG. 9 (A1) to (AN +) in which the signal level rises alternately at the optical spots SP1 and SP2 in the cycle of the vertical synchronizing signal S _V.
5)) can be obtained from the television camera 45.

Furthermore, when the switch 4D for aligning the optical axis in the vertical direction is turned on via the remote commander 8,
Enter the operation mode of aligning the optical axis in the vertical direction.

That is, as shown in FIG. 10, the transmitter 1 applies the video signal S _E to the waveform shaping circuit 63 (FIG. 5) to obtain a comparison output signal of a predetermined level, and thereby the optical spots SP1 and S1.
Waveform shaping signal whose logic level rises to logic "H" at P2
S _s (FIG. 10 (A)) is obtained and output to the vertical position detection circuit 64 and the horizontal position detection circuit 65.

As shown in FIG. 11, the vertical position detection circuit 64 supplies the vertical synchronization signal S _V (FIG. 10 (B)) and the waveform shaping signal S _s to the flip-flop circuit 66, and the signal level of the vertical synchronization signal S _V is changed. The logic level of the waveform shaping signal S _s becomes the logic “H” after the logic level rises to the logic “H” at the rising time t1.
Output signal whose logic level falls at time t2
Obtain S1 (Fig. 10 (C)).

The AND circuit 67 outputs the output signal S1 and the horizontal synchronization signal S _H (first
10 (D)), the output signal is output to the counter circuit 69 via the OR circuit 68.

Therefore, in the counter circuit 69, after the vertical synchronizing signal S _V rises, the waveform shaping signal is generated by the optical spot SP1 or SP2.
The period until the logic level of S _s rises to logic “H” can be detected by the value n represented by the number of horizontal scanning lines (FIG. 9).

On the other hand, the counter circuit 70 receives the waveform shaping signal S _s, and outputs the frequency-divided output signal S2 (FIG. 10 (E)) to the counter circuit 69 via the OR circuit 68.

As a result, the counter circuit 69 detects the number n of horizontal scanning lines and then calculates the size m of the light spot SP1 or SP2 by the number of horizontal scanning lines, which is 1/2 the value m / 2. It is possible to obtain a count value added to the value n (FIG. 9), which allows the vertical distance Y ₁ or Y ₂ from the scanning start end on the captured image to the center position of the optical spot SP1 or SP2 (see FIG. 7).
(Fig. And Fig. 8) can be detected by the number of horizontal scanning lines.

The counter circuit 69 outputs the count value D _Y to the latch circuits 74 and 75 via the multiplexer circuit 73.

The latch circuit 74 operates in synchronization with the frequency-divided signal S _2V , whereby the count value D _Y1 of the optical spot SP1 is changed.
Is then output to the subtraction circuit 76.

On the other hand, the latch circuit 75 operates in synchronization with the inverted signal S _21V of the frequency-divided signal S _2V obtained via the inverting amplifier circuit 77, whereby the count value D _Y2 of the optical spot SP2 is latched. After that, it outputs to the subtraction circuit 76.

Therefore, the distance Δy in the vertical direction between the light spots SP1 and SP2 can be detected by the number of horizontal scanning lines via the subtraction circuit 76, and thus the error in the irradiation position of the light beam LA1 with respect to the receiving device can be detected. You can

Therefore, the light beam LA for the receiving device is transmitted from the transmitting device 1 side.
The error of the irradiation position of 1 can be detected, and the optical axis of the light beam LA1 can be aligned based on the detection result, so that the optical axis can be aligned as a whole by a simple configuration.

That is, the drive circuit 78 detects whether the subtraction value representing the distance Δy is a positive value or a negative value, and drives the motor 26 so that the subtraction value becomes 0 based on the detection result. .

Therefore, in the light beam LA1 emitted from the transmitter 1, the direction of the optical axis is corrected so that the irradiation position coincides with the position of the optical spot SP2, and thus the optical axis can be aligned in the vertical direction. .

On the other hand, when the switch 4C for aligning the optical axis in the horizontal direction is turned on through the remote commander 8, the transmitter 1 enters the optical axis aligning mode in the horizontal direction.

That is, as shown in FIG. 12 and FIG. 13, the horizontal position detection circuit 65 uses the horizontal synchronizing signal S _H (FIG. 9 (B) and FIG. 13 (A)) and the waveform shaping signal S _s (FIG. 13). (B)) is applied to the flip-flop circuit 80, and the logic level of the waveform shaping signal S _s changes to logic “H” after the logic level rises to logic “H” at time t5 when the signal level of the horizontal synchronizing signal S _H rises. An output signal S5 (FIG. 13 (C)) whose logic level falls at the time t6 when it rises to "H" is obtained.

The AND circuit 81 outputs the output signal S5 and the subcarrier signal S _SC from the television camera 45 (Fig. 9 (C) and 13).
(D)), the output signal is output to the counter circuit 83 and is output to the delay circuit 82 having a delay time of one horizontal scanning period.

The counter circuit 83 is adapted to count the falling of the signal level of the horizontal synchronizing signal S _H is cleared, after which the the One rising horizontal sync signal S _H, the light Supotsuto
The logical level of the waveform shaping signal S _s is logical "H" at SP1 or SP2.
It is possible to detect the period up to the rise to the wave number N of the sub-carrier signal S _SC .

The comparator circuit 84 outputs an AND circuit 85 when the value N is less than or equal to a predetermined value.
To, and outputs a detection signal whose signal level rises in synchronization with the horizontal synchronizing signal S _H, thereby the output signal of the AND circuit 81 delayed by one horizontal scanning period which is outputted from the delay circuit 82, via the OR circuit 86 Output to the counter circuit 87.

In fact, when there is no optical spot SP1 or SP2 on the scan line, the signal level of the horizontal synchronizing signal S _H rises on the subsequent scan line without the logic level of the waveform shaping signal S _s rising to the logic "H".

Therefore, the output signal of the AND circuit 81 is output to the counter circuit 87 only when the count value N of the counter circuit 83 is less than or equal to a predetermined value, so that the optical spot SP1 or S on the scan line is output.
The resulting outputs subcarriers signals S _SC to only the counter circuit 87 if P2 is present, thus the light Supotsuto from scanning start end on the captured image through the counter circuit 87 SP1 or SP2
The horizontal distance to can be detected by the wave number of the subcarrier signal S _SC .

On the other hand, the counter circuit 90A has the sub-carrier signal S
_{Receive SC} and divide by 2 to output signal S ₆ (Fig. 13 (E))
Is output to the OR circuit 86 via the AND circuit 91A and the delay circuit 92A having a delay time of one horizontal scanning period.

Thus the counter circuit 87, sub-carrier signal S _SC
After counting the wave number N, the magnitude of the subcarriers signal S _SC becomes expressed in wave number value M of the light Supotsuto SP1 or SP2 1
It is possible to count the value M / 2 of / 2, whereby the horizontal distance X ₁ or X ₂ from the scanning start end on the captured image to the center position of the optical spot SP1 or SP2 (see FIGS. 7 and 8). Figure), can be detected in the wave number of the subcarriers signal S _SC (Figure 9).

The counter circuit 87 outputs the count value D _X to the multiplexer circuit 89 and also to the latch circuit 91 via the latch circuit 90.

The latch circuits 90 and 91 are adapted to operate in synchronization with the horizontal synchronizing signal S _H , whereby each of the latch circuits 90 and 91 is operated.
And 91, the count value D _X of two consecutive scan lines
Can be obtained.

The comparator circuit 92 obtains a detection signal in which the signal level rises when the count value output from the latch circuit 90 becomes larger than the count value output from the latch circuit 91, and falls when the count value does not change. ,
This is output to the multiplexer circuit 93.

The multiplexer circuit 93 divides the detection signal by the divided signal S
_The latch circuits 94 and 95 are switched to output according to the signal level of _2V .

The latch circuits 94 and 95 latch the count value output from the multiplexer circuit 89 at the falling timing of the detection signal.

Thus, for the scan lines that scan the centers of the optical spots SP1 and SP2 via the latch circuits 94 and 95, respectively,
The count values D _X1 and D _X2 are obtained and output to the subtraction circuit 96.

Therefore, the horizontal distance Δx between the optical spots SP1 and SP2 can be detected by the wave number of the subcarrier signal S _SC via the subtraction circuit 96.

Thus, the inverting amplifier circuit 77, the waveform shaping circuit 63, the vertical position detection circuit 64, and the horizontal position detection circuit 65, based on the video signal S _E obtained from the television camera 45, detect the receiving device (SP2) and the light beam LA1. Position detecting means for detecting the irradiation position (SP1) is configured.

The drive circuit 97 detects whether the subtraction value representing the distance Δx is a positive value or a negative value, and drives the motor 35 so that the subtraction value becomes 0 based on the detection result.

Therefore, in the light beam LA1 emitted from the transmitter 1, the direction of its optical axis is corrected so that the horizontal irradiation position of the light beam LA1 coincides with the horizontal position of the optical spot SP2. The optical axis can be aligned not only in the vertical direction but also in the horizontal direction.

Thus, in the horizontal direction as well as in the vertical direction, the transmitter 1 side can detect an error in the irradiation position of the light beam LA1 with respect to the receiver, and the optical axis can be aligned with a much simpler configuration than in the past. You can

Further, in this embodiment, the television camera 45
The motor 39 is controlled based on the video signal S _E obtained from
As a result, the light beam LA1 is emitted with a predetermined spread (in this case, parallel rays).

That is, in the transmitter 1, during the period T2 (FIG. 6), the waveform shaping signal S _s is applied to the optical spot diameter detection circuit (not shown), and the signal level of the waveform shaping signal S _s rises. , The spot diameter of the optical spot SP1 is detected by counting the wave number of the sub-carrier signal S _SC .

Further, based on the detection result, the motor 39 is drive-controlled to correct the position of the laser light source 41 with respect to the lens 42.

Thus, the shutters 55 and 56 are alternately opened and closed, and the light beam LA4 folded back by the collimating scope 46 and the light beam emitted from the receiving device are alternately turned on.
By guiding to 45, the optical spots SP1 and SP2 can be identified, and the spot diameter of the optical spot SP1 can be reliably detected.

Actually, when detecting the spot diameter of the optical spot SP1, if the image of the receiving device side and the image of the laser light source 41 are taken at the same time, it is difficult to identify which optical spot SP1 or SP2 is the optical spot of the light beam LA1. Not light spot SP1
Or, if SP2 is close, there is a problem that the spot diameter cannot be detected accurately.

Therefore, by alternately opening and closing the shutters 55 and 56 and alternately imaging the optical spots SP1 and SP2, not only is it possible to align the optical axis of the light beam LA1 with a simple configuration, but also the light beam LA1 The spread can also be detected reliably.

In the above configuration, the light beam LA1 emitted from the laser light source 41 and modulated by the predetermined information signal is reflected by the lens 4
It is converted into parallel rays via 2 and sent to the receiver.

Further, a part of the light beam LA1 is incident on the collimator scope 46 and is parallel to the optical axis of the light beam LA1.
Converted to A4.

The light beam LA4 is alternated with the light beam sent from the receiver by the shutters 55 and 56.
Guided by 45.

As a result, the light beam on the television camera 45
An image similar to the case where the laser light source 41 is arranged at the irradiation position of LA1 and an image on the receiving device side are alternately obtained in synchronization with the vertical synchronization signal S _V.

Television video signal output from the camera 45 S _E is
After being converted into a waveform shaping signal S _s whose logic level rises to logic “H” at the optical spots SP1 and SP2 via the waveform shaping circuit 63, it is output to the vertical position detection circuit 64 and the horizontal position detection circuit 65.

Thereby, in the vertical direction and the horizontal direction, the distance Y ₁ or Y ₂ and X ₁ or X ₂ from the scanning start end to the center position of the optical spot SP1 or SP2 are respectively the number of horizontal scanning lines and the sub-carrier signal S _SC . Detected by wave number.

The count values D _Y and D _X output from the vertical position detection circuit 64 and the horizontal position detection circuit 65 are latched by the latch circuits 74, 94 and 75, 95 for each of the optical spots SP1 and SP2, and then the subtraction circuit 76. And by being output via 96,
The vertical and horizontal distances Δy and Δx between the light spots SP1 and SP2 are obtained.

Subtracted values representing the distances Δy and Δx are output to the drive circuits 78 and 97, respectively, so that the distances Δy and Δx are obtained.
The motors 26 and 35 are driven so that the value becomes 0, and the light beam LA1 is aligned with the optical axis.

On the other hand, the motor 39 is drive-controlled based on the video signal S _E of the optical spot SP1 and the position of the laser light source 41 is corrected.

According to the above configuration, the light beam LA1 is folded back in parallel and is guided to the television camera 45 alternately with the light beam emitted from the receiving device side so that the transmitting device 1 side can identify the two light beams. It is possible to detect the irradiation position of the light beam LA1 and the position of the receiving device, and thus it is possible to align the optical axis with a much simpler configuration than in the past.

In the above-mentioned embodiment, the case where the shutters 55 and 56 made of liquid crystal optical elements are alternately opened and closed, but not limited to the shutter made of liquid crystal optical elements, other electric type shutters, and further mechanical type It can be widely applied to shutters and the like.

In this case, as shown in FIG. 14 and FIG. 15, a shading plate 98 having a notched portion at a predetermined angle is provided on the optical path in place of the shutters 55 and 56, and is synchronized with the vertical synchronizing signal by the motor 99. You may make it rotate.

Further, in the above-described embodiment, the half mirror 48 and
The case where the light beam LA1 is folded back in parallel using the 49 and the corner cubic prism 50 has been described.
And 49 may be replaced by a parallelogram prism.

Further, in the above embodiment, the case where the error of the optical spots SP1 and SP2 and the spot diameter of the optical spot SP1 are detected based on the horizontal synchronizing signal and the sub-carrier signal is described, but the error detecting means is not limited to this, for example, It can be widely applied to the case of counting other reference clock signals.

Further, in the above-mentioned embodiments, the optical spots are used.
Although the case where the error is detected after detecting the positions of SP1 and SP2 has been described, the present invention is not limited to this, and the position of the optical spot SP2 with respect to the direct optical spot SP1 may be detected.

Further, in the above-described embodiment, the optical spots SP1 and S
Although the case of detecting the spot diameter of the optical spot SP1 together with the error of P2 has been described, the present invention is not limited to this, and only one of the error of the optical spots SP1 and SP2 and the spot diameter of the optical spot SP1 is detected. Good.

Further, in the above embodiment, the case where the light spot SP2 is obtained by irradiating the light beam having a predetermined spread from the receiving device side is described, but the present invention is not limited to this, and the receiving device side to the transmitting device side are described. The emitted light beam may be used as a reference.

Further, in this case, the spot diameter of the optical spot SP2 may be detected and the detection result may be sent to the receiving device side.

Further, in the above-described embodiment, the case of performing the optical axis alignment of the servo system and the detection of the spot diameter is always described, but the present invention is not limited to this, and the optical axis alignment and the optical axis alignment are performed only when the transceiver is installed. The spot diameter may be detected.

Further, in this case, the error of the optical spots SP1 and SP2 and the spot diameter may be displayed, and manually adjusted based on the display result.

Further, in this case, instead of displaying the error of the optical spots SP1 and SP2, the positions of the optical spots SP1 and SP2 may be displayed.

H According to the present invention as described above, the emission light beam is folded back in parallel and is guided to the image pickup device alternately with the incident light beam from the receiving device side in the same direction together with the incident light beam. The deviation of the optical axis can be easily and easily discriminated on the transmitting device side based on the difference between the irradiation position of the emission light beam on the captured image and the installation position of the receiving device on the captured image.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a transmitter of an optical free space transmission apparatus according to an embodiment of the present invention, FIG. 2 is a perspective view showing a light beam irradiation optical system thereof, FIG. 3 is a sectional view thereof, and FIG. FIG. 5 is a schematic diagram showing a display image, FIG. 5 is a block diagram showing a transmitting device, and FIG.
FIG. 7 is a signal waveform diagram for explaining the operation, FIGS. 7 and 8 are schematic diagrams showing a display image when the shutter is switched, and FIG. 9 is a schematic diagram showing a relationship between a video signal and an optical spot. , FIG. 10 is a signal waveform diagram for explaining the operation of the vertical position detection circuit, FIG. 11 is a block diagram showing the configuration of the vertical position detection circuit, and FIG. 12 is a block diagram showing the configuration of the horizontal position detection circuit. Figure 13 is a signal waveform diagram used to explain the operation.
FIG. 14 is a front view showing another embodiment of the shutter, and FIG. 15 is a schematic diagram showing a state where the shutter is arranged on the optical path. 1 ... Transmission device, 3 ... Display device, 26, 35 ... Motor,
41 …… laser light source, 45 …… television camera, 46 ……
Collimating scope, 48, 49 …… Half mirror, 50 ……
Corner tube, 55, 56 ... Shutter, 64 ... Vertical position detection circuit, 65 ... Horizontal position detection circuit.

Claims (1)

(57) [Claims] 1. An optical space transmission device adapted to transmit the information signal to the receiving device via the emitting light beam by sending the emitting light beam modulated by the information signal to the receiving device. In the image pickup device, a part of the emission light beam is folded back in a direction opposite to and parallel to the optical axis of the emission light beam toward the reception device, and the emission light beam reception device is provided. An optical path turning means for obtaining an irradiation position light beam representing an irradiation position with respect to, an irradiation position light beam obtained from the optical path turning means, and an incident light beam coming from the receiving device side in a direction opposite to the emission light beam. Alternately, the shutter means for introducing into the image pickup device and the illumination on the picked-up image of the emission light beam sent to the receiving device based on the video signal obtained from the image pickup device. An optical space transmission device comprising: a position detection means for detecting a shooting position and an installation position on the captured image of the receiving device.