JPH08139678A - Optical radio transmitter/receiver - Google Patents

Abstract

PURPOSE: To improve the search accuracy of the optical transmitter/receiver and to improve the reception accuracy of signals. CONSTITUTION: In the case of optical radio transmission/reception to be performed between a first optical transmitter/receiver 2A constituted by turning a light transmission part 9A for transmitting optical signals at a narrow directional angle and a light reception part 10A for receiving the optical signals at a wider directional angle in comparison with the light transmission part toward the same direction and a second optical transmitter/receiver 2B for making possible the transmission of a signal for search excepting for the time of signal transmission by providing a light transmission part 9B for transmitting optical signals at a comparatively wider directional anble and a light reception part at a comparatively wider directional angle, the signal for search transmitted from the second optical transmitter/receiver 2B is received so that a first confirmation signal at a prescribed frequency can be transmitted from the first optical transmitter/receiver 2A, the signal for search is received by the second optical transmitter/receiver 2B so that a second confirmation signal can be transmitted and at the timing of reception at the first optical transmitter/receiver 2A, the direction of the first optical transmitter/receiver 2A corresponding to the second optical transmitter/receiver 2B is set.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical wireless transmitter / receiver for transmitting signals via optical wireless.

[0002]

2. Description of the Related Art Generally, a local area communication system is a LAN.
It is called a (local area network), and for example, in a relatively narrow limited area such as the same building, the same premises, or the school campus, wired or wireless signal transmission between terminal devices such as personal computers and printers is possible. It is well known that giving and receiving can be done.

Since these devices are originally intended for portable use, they are inconvenient to use while connected by wire. Therefore, it has been earnestly desired to make some or all of the transmission lines wireless to perform mutual communication.

As this type of wireless transmission means, it is advantageous to use wireless transmission of light, which is not legally regulated, as a medium for high-speed data transmission. Since the Ethernet LAN, which is the most popular wired LAN, has a transmission rate of 10 Mbps, it is desirable that the wireless transmission line has a transmission rate of 10 Mbps. Furthermore, if the wireless transmission path is used to completely replace the wired transmission path, bidirectional transmission becomes possible.

In this type of optical wireless transmission / reception device, if one transmission / reception device of a pair of transmission / reception devices is the transmission side and the other of the pair is the reception side, both devices are optical transmission / reception devices. It is desirable to have an optical receiver unit and a control unit.

For example, an optical transmitter on the transmitting side modulates an electrical information signal, photoelectrically converts the modulated electrical signal, and transmits it as an optical information signal from a light emitting element to a predetermined space (receiving side). . On the other hand, the receiving side is configured to photoelectrically convert the optical information signal modulated by the transmission from the transmitting side using the light receiving element of the optical receiving device, and demodulate the photoelectrically converted signal into the original electrical signal. Therefore, both the transmitting and receiving devices are equipped with the optical transmitting device and the optical receiving device, so that information signals can be transmitted and received bidirectionally.

For example, when a signal is transmitted via optical wireless as a signal transmission method, an LED is used as a light emitting element on the transmission side.
(Light emitting diode) and a laser diode are used, but the laser diode is used for transmission between buildings and transmission across rivers because the beam of emitted light is thin and does not spread even when transmitted over a long distance. However, since the beam diameter is extremely small, it may cause damage to the human body, especially when it enters the eyes, and therefore it cannot be used in a premises such as an office.

On the other hand, LEDs are not suitable for long-distance transmission because the LED has a wide directivity and the light beam spreads with distance.
The transmission distance can be extended by integrally forming the ED and the focusing lens. Since the optical noise generated by the illumination light mainly has a low frequency spectrum, the data is generally a broadband signal (substantially containing a DC component such as Manchester code) due to the modulation of FM or PM. Signal) and transmitted.

[0009]

By the way, in the case of performing wideband transmission using optical wireless communication or in the case of performing optical communication through a plurality of transmission lines of the same band in the same space, the light emission directivity and the light reception are obtained. Although it is necessary to narrow the directivity, the narrower the directivity is, the more difficult it is to accurately adjust the optical axis at the time of installation. Further, during communication, an error occurs due to some deviation of the optical axis due to vibration or the like.

As a conventional optical axis adjusting method using light having a narrow directivity, for example, as shown in Japanese Patent Publication No. 2-37997, a corner cube is provided on the other side, and a narrow directivity transmitted from itself is provided. There has been proposed a method of maximizing the light reception level of the light that is reflected by the corner cube on the other side and returned from the other side. However, this method also makes the mechanism complicated and increases the cost. Moreover, it is difficult to perform fine adjustment automatically at all times. Further, since the distance until the direction adjusting light reaches the receiving end becomes a path, there is a problem that the receiving level becomes ¼ compared to one way.

It is an object of the present invention to provide an optical axis adjusting method for an optical wireless device capable of automatically and finely adjusting the optical axis with a simple and inexpensive structure.

In the present specification, the transmission / reception device is a device having both a transmission device and a reception device, and the device is a device for performing communication between the transmission device and the reception device, or a transmission / reception device and a transmission / reception device. Two-way communication between them.

[0013]

The present invention has been made in view of the above problems, and a first invention is a first light transmitting section for transmitting an optical signal with a narrow directivity angle, and the light transmitting section. And a second optical transmitter / receiver configured to direct the first light receiving portion for receiving an optical signal with a wider directivity angle in the same direction, and a second optical transmitter / receiver for transmitting an optical signal with a relatively wider directivity angle. An optical wireless device that has an optical unit and a second light receiving unit that has a relatively wide directional angle, and that performs optical wireless communication with a second optical transmission / reception device that is capable of transmitting a search signal except during signal transmission. In the transmitter / receiver, the first confirmation signal of a predetermined frequency is received by the first light receiving unit, which is driven by the driving means in the predetermined direction and receives the search signal transmitted from the second optical transmitter / receiver. Is transmitted from the first optical transceiver, and transmitted from the first optical transceiver. The second confirmation signal is transmitted from the second light transmitting unit by receiving the generated first confirmation signal at the second light receiving unit of the second optical transceiver. Optical wireless transmission / reception in which the direction of the first optical transmitter / receiver device with respect to the second optical transmitter / receiver device is set at the timing when the first optical transmitter / receiver device receives the transmitted second confirmation signal. apparatus.

The presence or absence of a signal transmitted from the second optical transmitter / receiver driven in a predetermined direction by the drive means is received by the light receiving section of the first light receiving section having a wide directional angle, and the second optical transmission is performed. A second aspect of the invention is to set the direction of the first optical transceiver with respect to the second optical transceiver at the timing at which the first optical transceiver receives the transmitted second confirmation signal. An optical wireless transmission / reception device characterized by the above.

According to a second aspect of the invention, the first light transmitting section for transmitting an optical signal with a narrow directivity angle and the first light receiving section for receiving an optical signal with a narrow directivity angle and a wide directivity angle are in the same direction. A first optical transmission / reception device configured to face the first optical transmission / reception device, a ring-shaped second light transmission unit including a plurality of light emitting elements capable of transmitting a search signal and having an omnidirectional directivity angle; An optical wireless transmission / reception device that performs bidirectional optical communication with a second optical transmission / reception device, which includes a second light reception unit arranged in the central portion of the light transmission unit, and is driven in a predetermined direction by drive means, The second
If the presence / absence of a signal transmitted from the optical transmitter / receiver is received by the light receiver having a wide directional angle of the first light receiver, and the signal transmitted from the second optical transmitter / receiver is a search signal, The reception level is stored in the storage device based on the signal level received by the light receiving section of the first light receiving section of the first optical transmitter / receiver having a narrow directional angle, and when other signals are received, the search is temporarily stopped, and the search signal is returned. An optical wireless transmission / reception device, characterized in that a search is restarted by reception, a distribution of reception levels is detected, and a direction of the first optical transmission / reception device with respect to the second optical transmission / reception device is set.

Further, according to a third aspect of the invention, the first light transmitting section for transmitting an optical signal with a narrow directivity angle and the first light receiving section for receiving an optical signal with a narrow directivity angle and a wide directivity angle are in the same direction. A first optical transmitter-receiver configured to face, a ring-shaped second light-transmitting unit including a plurality of light-emitting elements having an omnidirectional directivity angle, and a second light-transmitting unit disposed at a central portion of the second light-transmitting unit. An optical wireless transmission / reception device for performing bidirectional optical communication with a second optical transmission / reception device including two light receiving portions, the optical wireless transmission / reception device being driven in a predetermined direction by a driving unit and transmitted from the second optical transmission / reception device. The signal level of the received signal received by the light receiving portion of the first light receiving portion having a narrow directional angle is detected, the reception level pattern is stored in the first storage device for each moving direction, and stored in the first storage device. And a second storage device in which the received level pattern is stored in advance. Of the reception level pattern of the first optical receiver / transmitter, and the direction of the first optical transmitter / receiver with respect to the second optical transmitter / receiver is set by the drive means based on the comparison result. An optical wireless transmission / reception device characterized in that communication is performed by a light receiving section having a wide directional angle.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, this type of optical wireless transmitter / receiver (hereinafter referred to as an optical transmitter / receiver) is an optical transmitter / receiver 2A, which is connected to information terminals 1A and 1B such as personal computers and printers, respectively. 2B face each other to exchange signals with an optical signal (dotted line), or, for example, to an Ethernet line 3 stretched around the ceiling of a predetermined space from an optical transceiver 2B connected to one terminal 1B. Optical signals (solid lines) are used to exchange signals with the disk-shaped optical transceivers 5A, 5B, 5C via the connected transceivers 4A, 4B, 4C.

As another method of use, an example of optical wireless video conference will be explained as shown in FIG. 2. In the terminals 8A and 8B, TV cameras 7A and 7B with a microphone and a TV monitor are installed in the terminals 8A and 8B as in the above embodiment. 6A and 6B are connected,
The optical transceivers 2A and 2B are arranged so as to directly oppose each other, and a video conference can be conducted by directly modulating and demodulating an image signal and an audio signal and transmitting the two-way optical communication.

An outline of this type of optical transmitter / receiver is constructed as shown in FIG. 3, for example.

That is, in order to realize bidirectional optical transmission, the optical transmitter 9A and the optical receiver 1 are arranged so that their optical axes are parallel to each other.
One optical transmission / reception device 2A in which 0A and 1A are vertically integrated
Further, it is desirable that the optical receiving device 10B and the optical transmitting device 10B are provided with an optical transmitting / receiving device 2B that is vertically integrated. The pair of optical transmitter / receivers 2A and 2B are assembled so that the optical axes of the transmitting and receiving semicircular parabolic reflectors are parallel to each other, and the optical transmitters 9A and 9B and the optical receivers 10A and 10B have the same structure. The other optical axis can be adjusted only by adjusting one optical axis. Reference numerals 11A and 11B denote drive mechanisms including stepping motors arranged in the optical transceivers 2A and 2B, and the optical transmitters / receivers 2A and 2B are rotationally driven by a predetermined angle in a vertical direction and a horizontal direction by a motor control circuit by scanning described later. It is a thing.

Specific configurations of the above-mentioned optical transmitter / receivers 2A and 2B are shown in FIGS. 4, 5 (a) and 5 (b).

As described above, the configurations of the optical transmitter / receivers 2A and 2B for bidirectional optical communication are opposite in the upper and lower sides, so only one optical transmitter / receiver 2A will be described, and the other side for transmitting and receiving will be described. The reference numeral B is attached to the device.

The optical transmitter / receiver 2A has a housing body 12A in which an optical transmitter 9A and an optical receiver 10A are vertically integrated.
The optical transmitter 2A on the upper side is provided with a lens-equipped LED 13A that emits a pilot signal (for example, a single wave of 5 MHz) that is a search optical signal having a wide directivity angle at the center position on the front surface. An LED 14A for signal transmission is provided on the back. The optical signal, which is the information signal transmitted from the signal transmitting LED 14A, is reflected by the semicircular parabolic reflector 15A and emitted as parallel light in front of the optical transmitter 9A.

On the other hand, the lower optical receiving device 10A facing the same direction as the upper optical transmitting device 9A receives the optical information signal transmitted from the above optical transmitting device and the transmitted pilot signal. The transmitted optical information signal and the transmitted pilot signal are reflected by the parabolic reflector 17A having a semi-circular shape and converged on the light receiving element 16A as an optical signal. The light-receiving element 16A and the light receiving element (light receiving unit) 16A ₁ with a narrow directional angle to the central portion, the light receiving element (light receiving portion) having a wide narrow beam angle so as to surround this 16A ₂ and what is more configuration Is.

The optical axes of the LEDs 13A and 14A and the light receiving element 16A and the parabolic reflectors 15A and 17 are provided.
Although it is a desirable form to match the centers of A, the assembly work requires a great deal of skill, and this assembly accuracy can contribute to the performance. This also applies to the form of FIG. 6 described later.

Assuming that the configuration of the optical transmitter / receiver 2B is different from that of the optical transmitter / receiver 2A, the optical transmitter 9A and the optical receiver 10 are different.
When A is located at the same position, the two transmission signals (optical axes) cross each other when attempting bidirectional communication between them. Then, when the one light emitting unit and the other light receiving unit are aligned closer to each other than the set distance between the both, the other light emitting unit does not face the one light receiving unit.

Therefore, the optical transmitter / receivers 2A, 2 having the above-mentioned structure
Since B is in the opposite mode, it becomes irrelevant to the distance between the two, and if the optical axes of the light receiving parts coincide with the light emitting parts of the other side, the optical axis of the light emitting part is always directed to the light receiving part of the other side. be able to.

The above optical transmitter 9A and optical receiver 10A
As shown in FIG. 5, the optical transmitter / receiver 2A is mounted on a fixed support 18 via left and right columns 19, and a stepping motor M1 for driving a rotary table 20 is driven to decelerate a gear mechanism or the like. It is rotated by a predetermined angle in the vertical direction via the mechanism 21, and is horizontally rotated by a predetermined angle in the left-right direction via a reduction gear mechanism (not shown) such as a gear mechanism driven by the stepping motor M2. The vertical and horizontal driving in the horizontal direction is controlled by a control signal from a search control circuit, which will be described later, and the turning range is set to, for example, 15 ° in the embodiment. It goes without saying that it can be appropriately set according to the distance between the transmitting / receiving devices 2A and 2B.

FIG. 6 is a schematic sectional view of a unit showing another embodiment of the optical transceiver. The optical transmitter / receiver 22 has a coaxial structure, that is, a structure in which a light receiving element 24 for receiving an optical signal and a light emitting element 25 for transmitting an optical signal are coaxially arranged in the housing 23 so that their optical axes are aligned with each other. A lens-equipped LED 26 that emits a pilot signal (for example, a single wave of 5 MHz), which is a search optical signal having a wide directivity angle, is arranged at a position on the front surface of the housing 23 that coincides with the optical axis. The light emitting element 25 is arranged.

The optical signal containing the optical information transmitted from the light emitting element 25 is reflected by the rear parabolic reflector 27 to become parallel light and is received from the front side by the optical receiving side of the optical transmitting / receiving side of the other side. . In addition, the light receiving element 24 arranged at the back of the housing 23 is the parabolic reflector 27.
Is arranged at the focal position of the parabolic reflector 29 having a large diameter. Similarly to the above, the light receiving element 24 is a light receiving element (light receiving portion) 24 ₁ having a narrow directional angle in the central portion.
And a light receiving element (light receiving section) 24 ₂ having a wide and narrow directivity angle surrounding the same, the search signal and the optical information signal incident in parallel as shown by the dotted line are reflected by the parabolic reflector 29. After being reflected by the reflecting mirror 28 arranged on the back surface of the parabolic reflector 27, the light receiving element 24 receives the signal as a predetermined signal.

The optical transmission / reception device 22 having the coaxial structure shown in FIG. 6 is preferably used as an optical transmission / reception device unit 30 integrated with a drive mechanism as shown in FIGS. 7 (a) and 7 (b). is there. FIG. 7 (a) is a front sectional view, FIG.
(B) It is a side view showing roughly.

That is, in FIGS. 7A and 7B, the optical transmitter / receiver 22 configured as described above has a box-shaped casing 31.
Is arranged on the upper part of the support shaft 32 and is rotatable in the vertical direction about the support shaft 32, while the casing 31 supports the support shaft 3 of the pedestal 32.
By being supported by the bearing 3 through a bearing 34, it is also rotatable in the left-right direction. The vertical drive is driven by a stepping motor M3, and is composed of a plurality of gear trains.
The deceleration mechanism 35 of FIG. A switch TSW is provided to detect the tilt end when the optical center axis of the optical transmitter / receiver 22 is oriented in the vertical direction (directly above). A spring 36 is provided between the support shaft 32 and the fixed portion.
Is stretched so as to absorb the backlash of the speed reduction mechanism 35, so that the setting operation of the optical axis between both devices and the position after setting are guaranteed during transmission and reception.

The optical transmitter / receiver 22 is driven in the left-right direction by being driven by the stepping motor M4 through the second reduction mechanism 37 to detect a panning end located at a predetermined rotational angle position. Switch P
The rotation angle position is detected by SW (not shown). A spring 38 is stretched between the support shaft 33 and the fixed portion and has the same function as the spring.

The drive mechanism and various detection switches as shown in FIGS. 7 (a) and 7 (b) are of course the same as those shown in FIG.
It is also attached to the optical transceivers 2A and 2B shown in FIG.

On the other hand, the main part of the present invention connected to the Ethernet line 3 arranged in a predetermined space as shown in FIG. 1 for performing bidirectional optical communication with the optical transmitter / receivers 2A and 2B. Disk-shaped optical transceivers 5A to 5C forming a part
The configuration will be described with reference to FIGS. 8 and 9.

The optical transmitter / receiver 5A (5B, 5C) is a cylindrical shield 42 in which a light receiving element 41 is housed in the center of a disk-shaped housing 40, and a circular shield is concentrically arranged around the shield 42. The light emitting element section 43 is composed of a first light emitting element group 43a and a second light emitting element group 43b. The upper part of the shield 42 is held by a cylindrical partition member 45, and a bowl-shaped cover 46 is attached via this partition member 45.

That is, the first and second discs are placed on the disc-shaped casing 40.
The printed circuit board 44 on which the light emitting element section 43 composed of the light emitting element group is mounted is fixed, and the cylindrical shield 42 accommodating the light receiving element 41 is attached to the central through hole 40a by the fixing means 48 such as a screw. It is fixed to the portion 40a. A plurality of omnidirectional LEDs 43a are arranged on the printed circuit board 44.
A first light emitting element group 43a in which 1 is arranged in an annular shape is attached so as to surround the light receiving element 41, and a plurality of omnidirectional LEs are provided outside the first light emitting element group 43a.
A second light emitting element group 43 in which D43b1 is arranged in a concentric manner in a ring shape.
b is attached concentrically. The optical axes of the LEDs 43a1 of the first light emitting element group 43a are attached so as to be inclined toward the outside of the housing 40 and upward with respect to the printed board 44 by a predetermined angle.

On the other hand, each LED 43b of the second light emitting element group 43b in which the above-mentioned plurality of LEDs 43b1 are concentrically arranged in a ring shape.
1 is each LED 43a1 of the first light emitting element group 43a
The LEDs 43b1 are arranged in the interposition, and the optical axes of the LEDs 43b1 face each other in the direction of the LEDs 43a1 of the first light emitting element group 43a and are inclined with respect to the printed board 44 by a predetermined angle. In this way, both first light emitting element groups 4
Since the optical axes of 3a and the second light emitting element group 43b face each other, the circles connecting the light source positions of both can be matched.

The light emitted from the first light emitting element group 43a is radiated outward as indicated by a chain double-dashed line, and the second light is emitted.
The light emitted from the light emitting element group 43b is emitted inward as shown by the alternate long and short dash line and, at the same time, is reflected outward by the plated reflecting mirror 45a formed on the outer peripheral surface of the cylindrical partition member 45. Is also emitted. In addition, this second light emitting element group 4
The outer edge of the light emitted from 3b is set to be located inside the tangent line of the circular protective cover 47 that covers the light receiving element 41.

Further, the shield 4 housing the light receiving element 41
A plated reflecting mirror 45b is provided on the inner surface of the cylindrical partition member 45 on the upper part of 2 in the same manner as described above, whereby the incident light including the information signal incident on the light receiving element 41 is directly or indirectly. Can receive efficiently.

Since the optical transmitter / receivers 5A to 5C can perform transmission / reception with a wide directional angle, a plurality of optical transmitter / receivers 2A and 2B are used.
One-to-N communication can be performed with the.

Here, the operation of setting the optical axis of the optical transmitter / receiver configured as described above will be described with reference to FIG.
Based on the transmission / reception mode of the optical transmitter / receiver connected to the Ethernet line shown in FIG. 8, the optical transmitter / receiver 2B in FIG. 4 and FIG. 5 described above and the optical transmitter / receiver connected to the Ethernet line 3 in FIG. 8 and FIG. A mode of bidirectional optical transmission / reception between the optical transmission / reception devices 5C having the configuration shown in FIG. 9 will be described, and one optical transmission / reception device 5C is set as a transmission side and the other optical transmission / reception device 2B is set as a reception side. This will be described with reference to the flowcharts of FIGS. In this embodiment, the light receiving element 16B of the optical transmitter / receiver 2B has only a light receiving element having a wide directional angle with respect to the directional angle of the light transmitting section.

For example, one optical transmission / reception device 5C on the transmission side for transmitting a predetermined information signal has the ring-shaped issuing element group 43.
It is possible to transmit a single-wave idle signal having a wide directivity of 5 MHz, a short packet signal, an information signal including data, and the like, and frequencies of the respective signals are assigned different frequencies.

First, the first light emitting element group 43a and the second light emitting element group 43b of the optical transmitter / receiver 5C on the transmitting side are caused to emit light at the same time, and an idle signal of a predetermined frequency (for example, of 5 MHz) which is an optical signal for searching. Single wave).

When the optical axis adjusting switch of the optical transmitter / receiver 2B on the receiving side is operated, the pilot lamp PB indicating the search mode is turned on, the optical transmitter / receiver 2B enters the search mode, and the search control circuit 50 operates. In this search control circuit 50, the optical transmitter / receiver 2B is initialized prior to the search operation, and drives the stepping motor M1 for vertical driving, for example.
After being rotated to a predetermined upper limit (or lower limit) rotation initial position, the stepping motor M1 is vertically driven within a predetermined angle range (for example, 30 °), and when the drive within the predetermined angle range is completed, The stepping motor M2 is driven to rotate the optical transmitter / receiver 2B in the horizontal direction by a predetermined angle (for example, 0.3 ° for a fine search and 3 ° for a coarse search), and this operation is performed by a predetermined angle (for example, 30 °). ), The drive is controlled sequentially. The search direction by the search control circuit 50 does not necessarily have to be performed in the vertical direction, and the stepping motor M2 operates first to scan the horizontal direction, and then the stepping motor M1 scans the vertical direction sequentially at a predetermined angle. Of course good things.

The motor control circuit 51 operates in response to a control signal from the search control circuit 50 to cause the optical transceiver 2 to operate.
Stepping motors M1 and M2 for operating B are sequentially driven (step S1). Then, the optical transceiver 2B on the receiving side is sequentially scanned in the vertical direction and the horizontal direction within a predetermined angle range. For example, the vertical direction is a stepping motor M
1 and the left and right directions by the stepping motor M2, eg, 0.
The operation is performed in a matrix form every 3 °, but the operation order may be reversed.

Optical scanning device 2B on the receiving side by the above scanning
16B with a wide directional angle of the light receiving element 16B in
Thus, the data signal and the idle signal are received from the above-mentioned transmitting-side optical transmitter / receiver 5C. If an idle signal is not transmitted from the transmitting side optical transmitter / receiver device 5C, that is, if the optical transmitter / receiver device 5C is transmitting / receiving a signal to / from another transmitter / receiver device 2A, the optical transmitter / receiver device 2B desiring to receive the signal. Is in a standby state.

The output converted as the reception signal by the first photoelectric conversion circuit 52 is supplied to the reception data processing circuit 54 via the decoding circuit 53. This reception data processing circuit 5
In step 4, it is judged whether the received signal is a data signal and an idle signal or a short packet signal (step S2), and if it is an idle signal, the information is sent to the CPU (central processing unit) 58. The CPU 58 sends the first short packet signal (confirmation signal) of a predetermined frequency stored in the ROM (read only memory) 59 to the LED 14B.
Will be transmitted (step S3). In this ROM 59,
Various information such as a first short packet signal having a predetermined frequency, optical axis correction data, and angular position pattern information of the light receiving element is stored in advance.

If the optical transmitter / receiver 5C does not receive the short packet signal (step S4), the optical transmitter / receiver 2B is used.
Then, by driving the search control circuit 50, the short packet signal is transmitted to the optical transmitter / receiver 5C side connected to the Ethernet line for each predetermined search angle position. When the signal from the transmitter / receiver 5C is changed to an information signal (data signal), the received data processing circuit 54 causes the CPU
A signal is sent to 58, and the motor control circuit 51 is stopped by the output of the search control circuit 50 to temporarily stop the search operation. When the optical transmitter / receiver 5C starts transmitting an idle signal again in this temporary stop state, the search operation is restarted.

When the optical transmitter / receiver 5C receives the short packet signal from the optical transmitter / receiver 2B, the optical transmitter / receiver 5C transmits a second short packet signal of a predetermined frequency (step S5). Optical transceiver 2B
If the second short packet signal cannot be received (step S6), the search is continued. If the second short packet signal can be received, the search control circuit 5 searches the control signal from the CPU 58 based on the reception timing.
Then, the motor control circuit 51 stops the stepping motors M1 and M2.

Then, the information signal from the optical transmitter / receiver 5C is received by the light receiving element 16B of the optical transmitter / receiver 2B, and the optical signal is received.
After the optical signal is converted into an electric signal by the electric conversion circuit 52, it is supplied to the decoding circuit 53, and the output thereof is supplied to the reception data processing circuit 54 and received by the terminal as a predetermined signal.

As described above, when transmitting / receiving the information signal, the state of the device on the other side (transmitting side) can be confirmed in advance by the idle signal, and other communication is not disturbed during the search operation.
Further, both sides can accurately set the transmission / reception position associated with the optical axis setting by a confirmation signal such as a short packet signal.

The following method is effective as another optical axis setting method for performing bidirectional communication.

The block diagram shown in FIG. 12 and the flowchart of FIG. 13 will be described below. The block diagram shown in FIG. 12 is different from FIG. 10 in that a light receiving element 16B ₁ having a narrow directional angle and a light receiving element 16B ₂ having a narrow directional angle are used as light receiving elements, and a photoelectric conversion circuit is connected to each light receiving element. Therefore, the same components as those in FIG. 10 are designated by the same reference numerals.

That is, similarly to the above, operating the drive switch of the optical transceiver 2B to drive the stepping motors M1 and M2 in an appropriate order by the control signal of the search control circuit 50 is the same as the above operation. The idle signal transmitted from the first light emitting element group 43a and the second light emitting element group 43b of the optical transceiver 5C connected to the Ethernet line 3 is received with a narrow directional angle within a predetermined search range of the optical transceiver 2B. Search with element 16B ₁ .

When any signal is transmitted from the optical transmitter / receiver 5C, the optical transmitter / receiver 2B desiring to receive operates the above-mentioned drive switch for starting the search.
The stepping motors M1 and M2 are driven in an appropriate order by the control signal of the search control circuit 50 (step S11), and the signal obtained by the light receiving element 16B is optically driven.
After being photoelectrically converted by the electric conversion circuit 55, it is supplied to the reception data processing circuit 54 via the decoding circuit 53, and when it is determined that the signal is an idle signal (step S12), the reception data processing circuit 54 idles. A signal indicating that the signal is a signal is supplied to the CPU 58, and the light receiving element 1 having a narrow directional angle.
Mapping is performed based on the reception of 6B ₁ . If the received signal is not an idle signal, a standby state is set (step S11).

After the idle signal is received, the signal received by the light receiving element 16B ₁ having a narrow directional angle is photoelectrically converted by the photoelectric conversion circuit 52 and then supplied to the level detection circuit 56. The signal level is detected based on the signal supplied by the level detection circuit 56 (step S14), and the level detection circuit 56 generates a DC voltage corresponding to the input level and supplies the DC voltage to the A / D converter 57. A map corresponding to the signal is created (step S15) and stored in the RAM 60. If it is a predetermined signal level (step S16),
The search is stopped by the control signal from the CPU 58 (step S17). That is, the optical axes of the first light emitting element group and the second light emitting element group are set by a predetermined level at the position where the matched light source is captured. Thus, the search by the light receiving element having a narrow directional angle is effectively performed.

If, in step S16, the level detection circuit 5
In 6, if the input level is not the predetermined level, the search is continued as long as the idle signal is transmitted (step S18). When the map is created during the continuation of the search and the idle signal from the optical transmitter / receiver 5C is interrupted, the standby mode is set in step S19. That is, the idle signal is interrupted when the optical transmitter / receiver 5C transmits / receives to / from another device (for example, the optical transmitter / receiver 2A), and if a signal is transmitted from the optical transmitter / receiver 2B at this time, the other transmitter / receiver is transmitted. It is effective to suspend the search because it may interfere and destroy the data. In this paused state, the communication between the optical transmitter / receiver 5C and other devices is completed,
When the idle signal is restarted at 0, similarly to the above-described map creation process, the creation of the map according to the received signal level is restarted from the map creation interruption position.

When the search is completed (step S22),
The optimum level position of the received signal level stored in the RAM 60 is detected (step S23), the signal level direction is read from the information stored in the ROM 59 by the CPU 58, and the control signal is searched for from the CPU 58 by the CPU 58 according to the read information. By driving the motor control circuit 51 via 50, the optical transmitter / receiver 2B is driven in the direction in which the optimum level position is obtained (step S23).

Here, even if the search in the predetermined angle range is completed in the above search, the level detection circuit 56 does not generate the DC voltage according to the input level, and if the predetermined level is not reached, the search range is completed. By this end, an error message is issued and the search ends. The search is restarted by operating the drive switch of the optical transceiver 2B again.

Both optical transmitters / receivers 5 by the above-mentioned scanning.
When the transmitting / receiving positions of C and 2B are set and the information signal which is the predetermined data is transmitted from the issuing element group 43 of the one optical transmitting / receiving apparatus 5C, it is received by the light receiving element 16B ₁ having a narrow directional angle of the optical transmitting / receiving apparatus 2B. The photoelectrically converted signal is photoelectrically converted by the photoelectric conversion circuit 52, and the signal received by the light receiving element 16B ₂ having a wide directional angle is photoelectrically converted by another photoelectric conversion circuit 55 and then added by the adder 61, The data is supplied to the reception data processing circuit 54 via the decoding circuit 53 and is received by the terminal device as predetermined data.

Further, another optical axis setting method will be described with reference to the block diagram of FIG. 12, the flow chart shown in FIG. 14 and FIGS.

This method is performed by using the ROM 59 in which a predetermined level pattern is stored.

That is, for example, one optical transmitter / receiver 5C and the optical transmitter / receiver 2B of the plurality of optical transmitters / receivers having the configuration of FIGS. 8 and 9 connected to the Ethernet line 3 in the same manner as described above.
In the transmission / reception mode with the optical transmission / reception device 5C, a search signal of a predetermined frequency such as an idle signal transmitted from the first light emitting element group 43a and the second light emitting element group 43b of the optical transmission / reception device 5C is subjected to a predetermined search of the optical transmission / reception device 2B. The light receiving portion 16B ₂ having a narrow directional angle within the range is searched.

The drive switch of the optical transmitter / receiver 2B is operated to operate the search control circuit 50 and the motor control circuit 51.
Is operated to drive the stepping motors M1 and M2 (step S31), which is the same as the above-mentioned starting modes.

The first light emitting element group 43 of the optical transceiver 5C
The circular search signal transmitted from a and the second light emitting element group 43b is subjected to signal level detection based on the signal received by the light receiving element 16B _{1 having} a narrow directional angle of the optical transmitter / receiver 2B. The optical-electric conversion circuit 52 converts the optical signal into an electric signal, and the output thereof is detected by the level detection circuit 56.
To detect the level (step S32). Then, the output of the level detection circuit 56 is supplied to a CPU (central processing unit) 58 via an A / D converter 57, and the level of the search signal scanned in a matrix can be rewritten into a storage device (RAM). 60 is sequentially stored for each scanning angular position to create a map (step S33).
(Step S34). If the search range has not ended, the same level detection is performed in step S22. Then, scanning is performed until the search range is completed (step S35), and when the scanning of the predetermined range is completed, the scanned result is stored in the rewritable storage device (RAM) 60, and the search signal level map is stored. The closest position of the light emitting element is obtained by the CPU 58 from the information (step S36), and this position is used as the reference point.

For example, as shown in FIG. 15, when the optical transmitter / receiver 2B desired to be transmitted is arranged directly below the optical transmitter / receiver 5C (position P1 ... For example, the distance 150 cm between the optical transmitter / receiver 5C and the optical transmitter / receiver 2B). The maximum signal level of the received signal is the same as the shape of the issuing element group 43 (annular-line diagram A) as shown in FIG.
The map of the search signal level stored in the RAM 60 is also circular.

Then, the correction amount distribution of the optical axis for the optical transmitter / receiver 5C is read from the read-only storage device (ROM) 59 in which the reception level pattern based on the setting information of the optical axis is previously stored for each reception angular position (step S37). ), RAM in which the reception level of the signal is written by the above scanning
R in which the reception level pattern is stored based on the information
With reference to the contents of the OM 59, the CPU 54 calculates and determines the correction amount of the optical axis, and supplies the result to the search control circuit 50 to drive the optical transceiver 2B (step S38).

Specifically, the RAM 6 is shown in FIG.
The maximum signal level stored at 0 is circular as shown in diagram A.

Diagram B shows an optical transmitter / receiver 2B corresponding to the optical transmitter / receiver 5C when the optical axis of the light emitting element 14B is aligned with Q.
It shows the area of light from.

Diagram C is a single ring-shaped light emitting pattern by the light emitting element group 43 consisting of the first light emitting element group 43a and the second light emitting element group 43b of the optical transmitter / receiver 5C located above, and observed from directly below. Then, of course, since it becomes a circle, the center O of the light receiving element 41 arranged at the center of the transmitter / receiver 5C as described in the above configuration is the light emitting pattern diagram C.
Coincide with the center of. Therefore, aiming at the center O of the light receiving element 41 in the optical transmitter / receiver 5C, the center Q of the light emission pattern transmitted from the light emitting unit 14B in the optical transmitter / receiver 2B.
Since it is displaced from (center Q of the diagram B) by the distance L, it is necessary to displace (correct) the transmission / reception angle of the optical transmission / reception device 2B by an angle corresponding to the distance L. The correction information is stored in the ROM 59 as a means for satisfying this request.

In FIG. 16A, the optical transmitter / receiver 5C is used.
When the angle between the optical transmitter / receiver 2B and the optical transmitter / receiver 2B is 60 degrees (distance 300 cm at position P4 in FIG. 15), the issuing element group 4 is
3, the maximum signal level pattern of the signal received by the optical transmitter / receiver 2B is only a part of the ellipse.
The CPU 58 calculates the center of the ellipse from the maximum signal level pattern of only a part of the ellipse stored in FIG. 8 and the light receiving pattern stored in advance in the ROM 59, and as a result, the correction distance L is calculated in the same manner as in FIG. Then, the transmission / reception angle may be displaced (corrected) by this distance L. The arrangement angles of 45 degrees (position P3 in FIG. 15) and 30 degrees (position P2) are also performed in the same manner below, and the details are omitted.

It should be noted that line D is a light emission pattern of the optical transmitter / receiver 5C.

When the optical axes coincide with each other by the above scanning, the device is switched to the reception mode, and the information signal transmitted by the light receiving element of the optical transmitter / receiver 2B having a wide directional angle is received.

[0075]

According to the optical wireless transmission / reception device of the present invention described in detail above, in the first aspect, the optical transmission / reception device, which is difficult to align the optical axis, can be automatically pointed at the other side. Optical axis alignment can be achieved, and the optical axis alignment time can be greatly shortened.

Further, according to the second aspect, there is an effect that the search time of the optical transmitting / receiving apparatus on the partner side for transmitting / receiving the optical transmitting / receiving apparatus can be minimized.

Further, in claim 3, a plurality of LEs are provided.
A plurality of optical transmitter / receivers can be transmitted / received to / from an optical transmitter / receiver based on a structure in which issuing elements such as D are arranged in an annular shape and a light receiving element is arranged in the center thereof, and moreover, are stored in advance when the optical axis is adjusted Since the reception level pattern of the light emitting element stored in the device is compared with the reception level pattern obtained by the search, it is possible to set the optical axis with high accuracy.

[Brief description of drawings]

FIG. 1 is a schematic explanatory diagram showing an embodiment of an optical wireless transmission / reception device of the present invention.

FIG. 2 is an explanatory diagram of an example of an optical wireless video conference using the optical wireless transmission / reception device of the present invention.

FIG. 3 is a conceptual diagram illustrating an optical axis adjustment mode between an optical transmitter-receiver on the transmitting side and an optical transmitter-receiver on the receiving side in the optical wireless transmitter-receiver of the present invention.

FIG. 4 is an explanatory diagram for explaining up / down and left / right operation states of the optical transceiver in the optical wireless transceiver of the present invention.

FIG. 5 is a diagram for explaining signal transmission / reception with a specific configuration of a biaxial transmission-side optical transmission / reception device and a reception-side optical transmission / reception device in the optical wireless transmission / reception device of the present invention.

FIG. 6 is a configuration diagram of a coaxial type optical transceiver in the optical wireless transceiver of the present invention.

7 is a side sectional view showing a drive mechanism of a coaxial type optical transceiver in the optical wireless transceiver of the present invention shown in FIG.

FIG. 8 is a side view showing the configuration of an optical transmitter / receiver on the transmitting side of the optical wireless transmitter / receiver of the present invention.

FIG. 9 is a schematic plan view showing the configuration of an optical transmitter / receiver on the transmitting side of the optical wireless transmitter / receiver of the present invention.

FIG. 10 is a block diagram showing an optical axis adjustment mode of the optical transceiver on the receiving side of the optical wireless transceiver of the present invention.

FIG. 11 is a flowchart of an optical axis adjustment mode in the first embodiment of the optical wireless transmission / reception device of the present invention.

FIG. 12 is a block diagram showing an optical axis adjustment mode of the second embodiment of the optical transmitter-receiver on the receiving side of the optical wireless transmitter-receiver of the present invention.

FIG. 13 is a flow chart of an optical axis adjusting mode in the second embodiment of the optical wireless transmitting / receiving apparatus of the present invention.

FIG. 14 is a flowchart of an optical axis adjustment mode in the third embodiment of the optical wireless transmission / reception device of the present invention.

FIG. 15 is a conceptual diagram illustrating an optical axis adjustment mode between an optical transmitting / receiving apparatus on the transmitting side and an optical transmitting / receiving apparatus on the receiving side in the third embodiment of the optical wireless transmitting / receiving apparatus of the present invention.

FIG. 16 is an explanatory diagram illustrating a reception level pattern of the optical receiving device on the receiving side in the third embodiment of the optical wireless transmitting / receiving device of the present invention.

[Explanation of symbols]

1A, 1B ... Personal computer, 2A ... Optical transmission / reception device (transmission side), 2B ... Optical transmission / reception device (reception side), 3 ... Ethernet line, 4A, 4B, 4C ... Transceiver, 5A, 5B, 5C ... Optical transmission / reception device, 7A , 7B ... TV camera, 9A, 9B ... Optical transmitting device, 10A, 10B ... Optical receiving device, 11A, 11B ... Driving mechanism, 13 ... Search LED, 14 ... Transmitting LED, 15, 17 ... Parabolic reflector, 16A, 16B ... light-receiving element, 16A _1, 16B ₁ ... narrow directivity angle of the light receiving element, 16A _2, 16B ₂ ... wide directivity angle of the light receiving element, 41 ... light-receiving element, 43 ... issued element group, 51 ... motor control circuit, 50 ... Search control circuit, 52, 55 ... Photoelectric conversion circuit, 53 ... Decoding circuit, 54 ... Reception data processing circuit, 56 ... Level detection circuit, 58 ... CPU, 5 ... ROM, 60 ... RAM.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H04B 10/28 10/26 10/14 10/04 10/06

Claims (3)

[Claims] 1. A first light transmitting section for transmitting an optical signal at a narrow directional angle and a first light receiving section for receiving an optical signal at a wider directional angle compared to the light transmitting section are directed in the same direction. And a second light transmitting section for transmitting an optical signal with a relatively wide directivity angle, and a second light receiving section with a relatively wide directivity angle. Other than the above, in an optical wireless transmission / reception device for performing optical wireless communication with a second optical transmission / reception device capable of transmitting a search signal, the optical transmission / reception device is driven in a predetermined direction by driving means and transmitted from the second optical transmission / reception device. The first confirmation signal of a predetermined frequency is transmitted from the first optical transmitter / receiver by receiving a search signal at the first light receiver, and the first confirmation signal transmitted from the first optical transmitter / receiver is transmitted. The first confirmation signal is sent to the second light receiving section of the second optical transceiver. By signal, the second from the second light transmitting unit
The confirmation signal is transmitted, and the direction of the first optical transmission / reception device with respect to the second optical transmission / reception device is set at the timing when the first optical transmission / reception device receives the transmitted second confirmation signal. An optical wireless transmission / reception device characterized by the above. 2. A first light transmitting section for transmitting an optical signal with a narrow directivity angle and a first light receiving section for receiving an optical signal with a narrow directivity angle and a wide directivity angle are formed in the same direction. 1. An optical transmitter-receiver unit 1, an annular second light-transmitting unit that is capable of transmitting a search signal, and includes a plurality of light-emitting elements having an omnidirectional directivity angle; and a central portion of the second light-transmitting unit. An optical wireless transmission / reception device that performs bidirectional optical communication with a second optical transmission / reception device that includes a second light receiving unit disposed in the second optical transmission / reception device, the optical transmission / reception device being driven in a predetermined direction by drive means. If the presence / absence of a signal transmitted from the device is received by the light receiving section of the first light receiving section having a wide directional angle, and the signal transmitted from the second optical transmitting / receiving apparatus is a search signal, the first Based on the signal level received by the light receiving section of the first light receiving section of Stores the received level in the storage device, temporarily stops the search at the time of other signals,
An optical wireless transmission / reception device, characterized in that a search is restarted by receiving a search signal, a reception level distribution is captured, and a direction of the first optical transmission / reception device with respect to the second optical transmission / reception device is set. 3. A first light transmitting section for transmitting an optical signal at a narrow directional angle, and a first light receiving section for receiving an optical signal at a narrow directional angle and a wide directional angle, which are configured in the same direction. 1 optical transceiver, an annular second light-transmitting part composed of a plurality of light-emitting elements having omnidirectional directivity angles, and a second light-receiving part arranged in the center of the second light-transmitting part. An optical wireless transmission / reception device for performing bidirectional optical communication with a second optical transmission / reception device, wherein the signal transmitted from the second optical transmission / reception device is driven by a drive means in a predetermined direction. The signal level received by the light receiving section of the light receiving section having a narrow directional angle is detected, the reception level pattern is stored in the first storage device for each moving direction, and the reception level pattern stored in the first storage device is stored. ,
The reception level pattern of the second storage device in which the reception level pattern is stored in advance is compared, and the first optical transmission / reception device for the first optical transmission / reception device is based on the compared result.
2. The optical wireless transmission / reception device, characterized in that the direction of the optical transmission / reception device is set by the drive means, and communication is performed by the light reception part having a wide directional angle of the first light reception part.