JPH11281863A - Optical axis adjusting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the optical axis adjusting operation of an optical space communicating system. SOLUTION: This optical axis adjusting device 10 is provided with a light reflecting part 12 reflecting light radiated from a light projecting and receiving device on a light projecting side arranged at a distance, a light projecting and receiving part 11 receiving the light reflected from the reflector 12A of the part 12, a light quantity measuring part 13 detecting the light receiving level of the part 11, a driving part 14 setting and driving the reflector 12A, and a control part 15 detecting a reflector position where the light receiving level becomes maximum based on the reflector position set by the part 14 and the light receiving level measured on the position and controlling the driving of the part 14 so as to set the reflector 12A on a maximum light receiving level position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical axis adjusting apparatus for transmitting light through a space, and more particularly, to an optical axis adjusting apparatus capable of extremely easily adjusting an optical axis between light emission and light reception.

[0002]

2. Description of the Related Art In recent years, space optical communication technology has been widely used in various fields. For example, the space optical communication technology has been used also in the field of traffic signals. As an example, there is a method used for information transmission between a vehicle detector and a traffic signal controller in a point detection control system of traffic control using a traffic signal.

In the point detection control system, a vehicle detector is installed at a remote point in front of a traffic signal, the presence or absence of a vehicle is detected by the vehicle detector to measure a traffic volume, and the measurement information is used as traffic signal control. To the machine. The traffic signal controller is attached to the traffic signal side to control the signal display of the traffic signal, and automatically controls the expansion and contraction of the blue lighting time of the traffic signal based on the received traffic information. As described above, the control method aims to smooth the traffic by controlling the signal indication according to the traffic volume at that time. In some cases, optical space communication technology is used for transmitting traffic information from the vehicle detector to the traffic signal controller.

In this case, both the vehicle sensor and the traffic signal controller are provided with light emitting and receiving devices for optical communication, and optical communication is performed between the two light emitting and receiving devices by spatial propagation. The advantage of using optical space communication is that the communication between the traffic signal controller and the vehicle detector can be performed wirelessly, eliminating the need for communication wiring equipment for connecting the two, and ensuring high reliability against electromagnetic noise. And the like.

[0005]

However, when such optical space communication is used, there is a disadvantage that it is difficult to align both optical axes during installation work. Conventionally, when performing optical axis alignment, the directions of both light emitting and receiving devices installed at remote locations are adjusted at the same time, and after confirming whether communication is possible, the light emitting and receiving unit is fixed. It was difficult to determine the direction of the device, and the installation work was difficult. In addition, in the case where the above-described operation is performed between the vehicle sensor and the traffic signal controller, there is a possibility that the optical axis may be shifted after installation due to vibration or ground subsidence due to the passage of the vehicle. Must perform the complicated optical axis alignment work as in installation.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide an optical axis adjusting apparatus that can extremely easily perform an optical axis adjusting operation between light emission and light reception when performing optical space communication. .

[0007]

Therefore, in the optical axis adjusting device according to the first aspect of the present invention, a drivable light reflecting member for reflecting light emitted from a light projecting side arranged at a distance. Means, light receiving means for receiving the reflected light from the light reflecting means, light level detecting means for detecting the light receiving level of the light receiving means, driving means capable of driving the light reflecting means to any set position, Position detecting means for detecting the position of the light reflecting means having the maximum light receiving level based on the light reflecting means position set by the driving means and the light receiving level detected by the level detecting means at the position; And control means for controlling the driving means so as to set the light reflection means at the maximum light receiving level position detected by the detection means.

In this configuration, the light from the light projecting side is reflected and guided to the light receiving means while the position of the light reflecting means is shifted by, for example, a predetermined angle by the driving means. The level detecting means detects a light receiving level based on a light receiving output from the light receiving means. The position detecting means detects the position of the light reflecting means having the maximum light receiving level based on each position of the light reflecting means and the light receiving level at each position. The control means controls the driving of the driving means so as to set the light reflecting means at the position where the maximum light receiving level is detected by the position detecting means.

According to a second aspect of the present invention, there is provided signal light generating means for projecting the signal light toward the light projecting side via the light reflecting means, while the signal light is provided on the light projecting side. It is preferable to provide a light projection control means for projecting light toward the light reflection means when receiving light. With such a configuration, the optical axis can be automatically adjusted by receiving the signal light from the signal light generating means on the light projecting side.

The signal light control means controls the signal light generating means to generate the signal light when it is detected that the light receiving level of the light receiving means has fallen below a set value. It is good to have composition provided with a means. In such a configuration, the optical axis can be automatically adjusted when the light receiving level decreases, so that the light on the light projecting side can always be received in a good state.

The light reflecting means may use a semiconductor galvanomirror manufactured by using a semiconductor manufacturing technique. In such a configuration, by using the semiconductor galvanometer mirror, the size of the optical axis adjusting device can be reduced. An optical axis adjusting device according to the present invention is configured to perform spatial light communication between a traffic signal controller installed on a road side and a vehicle sensor at a distance from the traffic signal controller. The present invention can be applied to adjustment of an optical axis between a pair of light emitting and receiving devices provided in a vehicle sensor.

If the present invention is applied to an optical space communication device between a traffic signal controller and a vehicle detector, the optical axis may be shifted due to vibration or the like accompanying the traffic of the vehicle, only the optical axis alignment work becomes easy. In addition, the optical axis can be easily adjusted even after the setting and installation, so that maintenance and the like become easy. Further, the optical axis adjusting device of the present invention can be applied to a light emitting and receiving device for optical space communication provided in a personal computer, as described in claim 6.

[0013] With this configuration, the degree of freedom of the installation location between the personal computers is increased.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the optical axis adjusting device of the present invention, which is an example applied to an optical communication device between a traffic signal controller and a vehicle detector. In FIG. 1, road 1
The traffic signal 2 installed on the road side of the road is provided with a traffic signal controller 4 for controlling the signal display of the signal light 3 on an upright column, and the traffic signal controller 4 supporting the signal lamp 3 projecting toward the road 1 will be described later. A light emitting and receiving device 5 for optical space communication including the optical axis adjusting device of the present embodiment is provided so as to be electrically connected to the traffic signal controller 4.

A vehicle sensor 6 as a light emitting side provided on a road side at a predetermined point separated from the traffic signal 2 is provided with a sensor main body 6A provided on an upright support and a support protruding toward the road 1 side. And a sensor unit 6B for supporting and detecting a vehicle 7 passing through the lower road 1. Also,
A light emitting and receiving device 8 for performing spatial optical communication with the light emitting and receiving device 5 on the traffic signal 2 side on the tip end side of the support supporting the sensor unit 6B.
Is provided.

Next, the schematic configuration of the optical axis adjusting device built in the light emitting and receiving device 5 will be described with reference to FIG. In FIG. 2, an optical axis adjusting device 10 of the present embodiment includes a light emitting and receiving unit 11 that emits and receives light, an external light that reflects toward the light emitting and receiving unit 11, Drivable reflector 12A for reflecting the light emitted from light source 11 to the outside
A light reflecting unit 12 as a reflecting unit, a light amount measuring unit 13 as a light level detecting unit for detecting a light receiving level of the reflected light received by the light emitting and receiving unit 11, and the light reflecting unit 1
The drive unit 14 as a drive unit capable of driving the second reflector 12A to an arbitrary set position, the reflector position set by the drive unit 14, and the light reception level measured by the light amount measurement unit 13 at that position. And a control unit 15 as a control unit incorporating a microcomputer, for example, for detecting the position of the reflection plate at which the light reception level becomes maximum and controlling the driving unit 14 to set the reflection plate at the maximum light reception level position. It is configured with. Therefore, the control unit 15 has a function of a position detecting unit.

The light emitting and receiving unit 11 receives traffic information based on an optical signal transmitted from the vehicle detector 6 through the light reflecting unit 12 and controls the traffic signal so as to reflect the traffic information on the signal display. To the machine 4. The traffic signal controller 4 appropriately controls the indication of the traffic light 3 based on the received traffic information. Specifically, for example, the extension / contraction control of the lighting time (indicating the progress) of the green traffic light is performed. In addition, the traffic signal controller 4 includes:
A function corresponding to light projection control means for emitting signal light from the light emitting / receiving unit 11 is provided. Therefore, the light emitting and receiving unit 11 functions as a signal light generating unit. In this case, the light emitting and receiving device 8 on the vehicle sensor 6 side has a function of light emitting control means for emitting light toward the light emitting and receiving device 5 on the traffic light 2 when receiving the signal light.

Next, a specific configuration of the light reflecting section 12 will be described. In the present embodiment, a semiconductor galvanomirror manufactured using a semiconductor manufacturing technique is used for the light reflecting portion 12. This semiconductor galvanomirror is disclosed in Japanese Patent Application Laid-Open Nos. 7-175005 and 7-218857 by the present applicant.
Since these have been proposed in Japanese Unexamined Patent Publications and the like and are described in detail in each of the above publications, they will be briefly described here.

FIG. 3 is an exploded perspective view of an example of a semiconductor galvanomirror suitable as the light reflecting portion 12 of the present embodiment. In FIG. 3, a semiconductor galvanomirror 200 has an outer movable plate 204A pivotally supported on a silicon substrate 201 by a torsion bar 205A so as to be vertically swingable.
4B is pivotally supported in the vertical direction of the substrate by a torsion bar 205B whose axis is orthogonal to the torsion bar 205A. The outer movable plate 204A is formed in a frame shape, and has a planar coil 206A (which is electrically connected to a pair of outer electrode terminals 209A and 209A formed on the upper surface of the silicon substrate 201 via one portion of the torsion bar 205A on the upper surface thereof). (In the figure, schematically indicated by a single line) is provided covered with an insulating layer. Also, the inner movable plate 20
4B is formed in a plate shape, and a pair of inner electrode terminals 209B, 20B formed on the silicon substrate 201 is formed on the upper surface thereof.
9B to the outer movable plate 2 from one of the torsion bars 205B.
A plane coil 206B (schematically indicated by a single line in the figure) which passes through the portion 04A and is electrically connected to the torsion bar 205A via the other side is provided so as to be covered with an insulating layer. Inner movable plate 204 surrounded by planar coil 206B
At the center of B, a total reflection mirror 208 is formed. The total reflection mirror 208 corresponds to the reflection plate 12A of the light reflection section 12.

Upper and lower glass substrates 202 and 203 made of, for example, borosilicate glass are anodically bonded to the upper and lower surfaces of the silicon substrate 201, respectively. The upper glass substrate 202 has a square opening 202A at the center of the flat plate portion.
And the upper portion of the movable plate is open. The lower glass substrate 203 has a square groove 203 in the center of the flat plate.
A. Thereby, the upper and lower glass substrates 20
2, 203 and the silicon substrate 201 have a three-layer structure to secure a swinging space for both movable plates 204A, 204B.

The upper and lower glass substrates 202 and 203 each have a pair of two permanent magnets 21 each having eight magnets.
0A to 213A and 210B to 213B are arranged as shown. The permanent magnets 210A and 211A of the upper glass substrate 202 facing each other are
Generates a magnetic field for driving the outer movable plate with the permanent magnets 210B and 211B. The permanent magnets 212A and 213A of the upper glass substrate 202 facing each other generate a magnetic field for driving the inner movable plate with the permanent magnets 212B and 213B of the lower glass substrate 203.

Next, the principle of operation of the semiconductor galvanomirror 200 will be briefly described. For example, the electrode terminal 209
A and 209A have one of them as a positive pole and the other as a negative pole, and a current flows through the plane coil 206A. On both sides of the outer movable plate 204A, a magnetic field is formed by the permanent magnets 210A and 210B and the permanent magnets 211A and 211B in a direction crossing the plane coil 206A along the plane of the outer movable plate 204A. When a current flows through the planar coil 206A in the magnetic field, the current is applied to both ends of the outer movable plate 204A in accordance with the current density and the magnetic flux density of the planar coil 206A in a direction according to the left-hand rule of Fleming of current, magnetic flux density, and force. The force acts, and the outer movable plate 204A rotates. When the outer movable plate 204A rotates, the torsion bar 205A is twisted, and the outer movable plate 204A is turned to a position where the spring reaction force of the torsion bar 205A generated thereby and the electromagnetic force acting on the outer movable plate 204A are balanced. Move.

At this time, the displacement angle of the outer movable plate 204A is proportional to the current flowing through the plane coil 206A. Therefore,
By controlling the current flowing through the planar coil 206A,
The displacement angle of the outer movable plate 204A, that is, the total reflection mirror 208 can be controlled. If the relationship between the amount of current flowing through the planar coil and the displacement angle of the movable plate is determined in advance, the total reflection mirror 208 can be set at a desired displacement angle position by controlling the amount of current.

The inner movable plate 204B is
By rotating around the torsion bar 205B as an axis according to the same operating principle as that of A, the displacement angle can be controlled by controlling the amount of current flowing through the planar coil 206B. By controlling the rotation of the outer and inner movable plates 204A and 204B in this manner, the reflection position of the total reflection mirror 208, that is, the reflection plate 12A can be variably controlled. And both movable plates 204A,
By appropriately controlling 204B simultaneously, it becomes possible to receive and reflect the incident light in the range as shown by the broken line in FIG. 4, and the range in which the optical axis can be adjusted can be widened. FIG. 4A shows the optical axis adjustable range.

A detection coil (not shown) for detecting the displacement of the outer movable plates 204A, 204B based on the mutual inductance with the planar coils 206A, 206B is provided on the lower glass substrate 203, and each torsion bar 205
A and 205B are preferably provided symmetrically. In this case, when controlling the displacement angle of the mirror 208, a displacement angle detection current having a frequency higher than the drive current frequency is supplied to the plane coil 206A so as to be superimposed on the drive current. Then, based on this detection current, an induced voltage is generated in each detection coil by mutual inductance between the planar coil 206A and the detection coil provided on the lower glass substrate 203. When the outer movable plate 204A is in the horizontal position, the distance between the induced coils generated in the detection coils is equal to the distance between each detection coil and the corresponding planar coil 206A, and the difference is zero. When the outer movable plate 204A rotates around the torsion bar 205A due to the electromagnetic force, the one detecting coil approaches and the induced voltage increases due to an increase in the mutual inductance, and the other detecting coil separates to induce an induced voltage due to a decrease in the mutual inductance. The voltage drops. Therefore, the induced voltage generated in both the detection coils changes according to the displacement angle of the movable plate, and by detecting this induced voltage, the movable plate, that is,
The displacement angle of the total reflection mirror 208 can be detected. Then, for example, a bridge circuit or the like is used to feed back an induced voltage difference generated between the two detection coils to a drive system of the outer movable plate 204A via a differential amplifier to control the drive current. It is possible to control the displacement angle of 208 more precisely.

Next, the operation of the optical axis adjusting device 10 of the present embodiment will be described. A signal light for notifying the start of the optical axis adjustment operation is transmitted from the light emitting and receiving device 5 of the traffic signal controller 4 to the light emitting and receiving device 8 of the vehicle detector 6. Upon receiving the signal light, the light emitting and receiving device 8 emits light toward the light emitting and receiving device 5. This light is reflected by the reflection plate 12A of the light reflection unit 12, enters the light projection / reception unit 11, and the light reception level is measured by the light amount measurement unit 13. At this time, the control unit 15 stores in advance the relationship data between the drive current value and the position of the reflector 12A, and based on the data, determines the position of the reflector 12A of the light reflector 12 via the drive unit 14. set. Then, while varying the position of the reflector 12A at a preset interval, the light receiving level at each reflector position is measured. In this way, the position of the reflector 12A at which the light receiving level becomes maximum is detected, the reflector 12A is fixed at the position of the maximum light receiving level, and the optical axis adjustment ends.

According to this configuration, after the directions of the light emitting and receiving devices 5 and 8 are roughly set and fixed, the optical axis adjustment operation described above may be performed to adjust the optical axis. Therefore, since it is not necessary to accurately align the directions of the two light emitting and receiving devices 5 and 8 at positions separated from each other as in the related art, the optical axis adjustment work is greatly facilitated. 8 can be easily installed.

By automatically and periodically performing the above-described optical axis adjustment, it is possible to prevent the optical axis from being shifted due to the influence of vibration, land subsidence, etc., and to improve the reliability of the point sensing control method in traffic signal control. . Also, as shown by the dotted line in FIG.
When the light receiving level measured by the light quantity measuring unit 13 is input to the traffic signal controller 4 and the traffic signal controller 4 receives the detection signal of the light receiving level and detects that the light receiving level has become a predetermined value or less, A function corresponding to signal light control means for emitting signal light from the light emitting and receiving unit 11 is provided.

With this configuration, when the optical axis shifts due to, for example, vibration or land subsidence, and the light receiving level falls below a predetermined value, the optical axis adjusting operation is automatically performed. Optical space communication between the devices can always be performed in a good state, and the reliability of the point sensing control method in traffic signal control can be further improved. Next, FIG. 5 shows an optical axis adjusting device according to the present invention, which is a notebook-type personal computer (hereinafter, referred to as a personal computer).
Here is an example in which the present invention is applied to a personal computer).

FIG. 5A is a view from the side,
5B is a view as viewed from above. As shown in FIG. 5, for example, the optical axis adjusting device 10 shown in FIG. In this configuration, when performing optical space communication using infrared light with another notebook computer 22, as described above, the mutual optical axis adjustment device 10 variably controls the position of the reflection plate to move infrared light up and down.・ Shift to the left and right to adjust the optical axis, set the optimal communication conditions, and then perform communication.

Conventionally, when optical space communication using infrared rays is performed between personal computers, it is necessary to make the emission positions of the infrared rays substantially confront each other, and the installation positions of the personal computers are severely restricted. By applying 10, the above-mentioned restrictions are relaxed, the degree of freedom of the installation position of the personal computer is increased, and the usability is improved. Next, FIG. 6 shows the optical axis adjusting device of the present invention.
For example, an example in which the invention is applied to optical space communication of a company telephone is shown.

As shown in FIG. 6, for example, the above-described optical axis adjusting device 10 is installed at a high position such as a ceiling in a room. Then, the direction of the signal light between the in-house telephones 31 and 32 transmitted and received by each other is adjusted by the optical axis adjusting device 10 so that the reception level is maximized, and the in-house telephones 31 and 32 are transmitted via the optical axis adjusting device 10. Send and receive signal light between them and talk. According to such a configuration, even when the positions of the in-house telephones 31 and 32 are changed, there is an advantage that the optical axis can be extremely easily adjusted and the communication state can be easily set to the best.

In the traffic control of the point detection system,
Conventionally, the information transmission between the traffic signal controller and the vehicle detector has a one-to-one relationship.
7 is applied to one light emitting / receiving device 5 on the traffic signal controller 4 side, and the light emitting / receiving device 8 on each of the vehicle sensors 6-1 to 6-3 at a plurality of points, as shown in FIG. It becomes possible to transmit vehicle sensing information from -1 to 8-3.

That is, the optical axis adjusting device 10 automatically adjusts the optical axis between the light emitting and receiving device 5 and the light emitting and receiving device 8-1 to obtain vehicle sensing information. Next, after automatically adjusting the optical axis of the light emitting and receiving device 8-2 in the same manner, vehicle sensing information is obtained. This operation is sequentially performed on all of the light emitting and receiving devices 8-1 to 8-3 on the vehicle sensor 6-1 to 6-3 side. By performing this periodically, it becomes possible to transmit the vehicle sensing information of a plurality of places to one traffic signal controller 4, and the quality of the traffic control system can be further improved. It is needless to say that the number of vehicle sensors is not limited to three but may be more.

[0035]

As described above, according to the first aspect of the present invention, the optical axis adjustment work in the optical free space communication apparatus is greatly facilitated, and the optimum light transmission / reception conditions can be set. According to the invention of claim 2, in addition to the effect of the invention of claim 1, signal light can be emitted from one side by operation from one side, and the optical axis can be adjusted by operation from one side. In addition, automatic optical axis adjustment becomes possible.

According to the third aspect of the invention, in addition to the effect of the second aspect, optical space communication can always be performed under optimum conditions. According to the invention of claim 4, the optical axis adjusting device can be made extremely small. According to the fifth aspect of the present invention, even if the optical axis is displaced due to the influence of vibration, land subsidence, or the like after the optical axis is set, the optical axis deviation can be easily corrected. Further, by providing the configuration of claim 3, it is possible to prevent the optical axis deviation beforehand, and it is possible to improve the reliability of the point sensing control method.

According to the sixth aspect of the present invention, the restrictions on the locations of the personal computers at the time of the optical space communication between the personal computers are relaxed, and the usability is improved.

[Brief description of the drawings]

FIG. 1 is a traffic control system diagram to which an embodiment of an optical axis adjusting device according to the present invention is applied.

FIG. 2 is a block diagram of the optical axis adjusting device used in FIG.

FIG. 3 is an explanatory view of a semiconductor galvanomirror.

FIG. 4 is a diagram showing a light emitting and receiving device according to the first embodiment;

FIG. 5 is an explanatory diagram when the optical axis adjusting device of the present invention is applied to a personal computer.

FIG. 6 is an explanatory diagram when the optical axis adjusting device of the present invention is applied to an in-house telephone.

FIG. 7 is an explanatory diagram of another application example of the traffic control system using the optical axis adjusting device of the present invention.

[Explanation of symbols]

 5, 8 light emitting and receiving device 10 optical axis adjusting device 11 light emitting and receiving unit 12 light reflecting unit 12A reflector 13 light quantity measuring unit 14 driving unit 15 control unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04B 10/105 H04B 9/00 R 10/10 10/22 (72) Inventor Masami Hasegawa Hirade Industrial Park 11-, Utsunomiya City, Tochigi Prefecture 2 Inside the Utsunomiya Office of Signal Corporation

Claims (6)

[Claims] 1. A drivable light reflecting means for reflecting light radiated from a light projecting side arranged at a distance, a light receiving means for receiving light reflected from the light reflecting means, and A light level detecting means for detecting a light receiving level; a driving means capable of driving the light reflecting means to an arbitrary set position; a light reflecting means position set by the driving means; and a position detected by the level detecting means at the position. Position detecting means for detecting the position of the light reflecting means at which the light receiving level is maximum based on the received light level, and the driving means for setting the light reflecting means at the position of the maximum light receiving level detected by the position detecting means. And a control means for controlling the optical axis. A signal light generating means for projecting the signal light toward the light projecting side via the light reflecting means; and a light reflecting means for receiving the signal light on the light projecting side. An optical axis adjusting device, characterized in that it is provided with a projection control means for projecting light toward the optical axis. 3. A signal light control means for controlling said signal light generating means so as to generate said signal light when detecting that the light receiving level of said light receiving means has fallen below a set value. The optical axis adjusting device according to claim 2. 4. The optical axis adjusting device according to claim 1, wherein said light reflecting means is a semiconductor galvanometer mirror manufactured by using a semiconductor manufacturing technique. 5. A pair of light emitting and receiving devices provided in the traffic signal controller and the vehicle sensor for performing optical space communication between the traffic signal controller and the vehicle sensor installed at a distance on the road side. 3. The method according to claim 1, wherein the optical axis is adjusted between
5. The optical axis adjustment device according to any one of 4. 6. The method according to claim 1, wherein the light emitting and receiving device is provided in a personal computer for spatial light communication.
The optical axis adjustment device according to any one of items 1 to 4,