JPH07131422A - Optical axis alignment method for optical radio transmission equipment - Google Patents

Abstract

PURPOSE:To provide the optical axis alignment method for optical radio transmission equipment capable of easy alignment of the optical axis of an optical radio transmission equipment. CONSTITUTION:An optical radio transmission equipment 1 consists of a transmission equipment 2 which generates first transmission light for signal transmission and a reception equipment 3 which converts the light received by a photodetector PD 4 to an electric signal and outputs it as the output signal, and the reception equipment 3 puts reception level information of the reception signal detected by a level detector 13 on a pilot signal to transmit it to the transmission equipment 2. The transmission equipment 2 takes out reception level information from the received pilot signal and displays the reception level on a level monitor 6, and the optical axis of the transmission equipment 2 is adjusted, thus aligning the optical axis.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of aligning an optical axis of an optical wireless transmission device, which is capable of easily aligning the optical axis of the optical wireless transmission device.

[0002]

2. Description of the Related Art Conventionally, there is an optical wireless transmission technique for spatially transmitting information by using light. Infrared light is generally used for this optical wireless transmission, and a semiconductor light emitting element such as a light emitting diode or a laser diode is used as a light emitting element thereof. In such optical wireless transmission, if it is desired to secure a sufficient distance between transmission and reception, it is necessary to sharply narrow the directivity of the light beam emitted from the transmission device so that a sufficient light level is incident on the reception device side. Therefore, the transmitter,
It is necessary to match the optical axes of the receiving device and the optical axis of the receiving device. However, since a light beam with a narrow directivity is used and the light beam uses invisible infrared light, Aligning the optical axes is a very cumbersome task. Therefore, conventionally, there has been proposed an optical wireless transmission device capable of easily performing the optical axis alignment.

As one example thereof, visible light provided on the receiving device side by narrowing visible light from a transmitting device to a pinpoint and sending it together with infrared light for signal transmission along the same optical axis or parallel optical axis An optical wireless transmission device for adjusting the optical axis of a transmission device while an operator looks at the visible light reflected by the visible light reflection device and is applied to the reflection device is disclosed in JP-A-62-11033.
No. 9 publication. Another technique is to install a sighting device on the transmitter and connect an optical wireless transmission device that aligns the optical axis while looking at the sighting device, or a measuring device for detecting the received light level on the receiving device side. There is also an optical wireless transmission device that performs optical axis alignment as a set.

[0004]

By the way, the optical wireless transmission device as disclosed in the above-mentioned Japanese Patent Laid-Open No. 62-110339 causes the transmitting device to generate visible light used for purposes other than optical wireless transmission. Needing configuration. If you want to keep a sufficient distance between the transmitter and receiver, you must make this visible light emission output large enough.
Since it is necessary to add the configuration, the cost of the transmitter increases, and the size of the device increases. This is also the case when the sighting device is installed in the transmitter. Further, it is necessary to strictly align the optical axis of visible light and the sight of the sighting device with the optical axis of infrared light for signal transmission, which also increases the cost. Further, even when the light receiving level detecting measuring device is connected to the receiving device and performed by two persons, there are drawbacks such that it is necessary to prepare the light receiving level detecting measuring device and labor is required. As described above, in the conventional optical wireless transmission device, if the optical axis alignment is simplified, the cost of the transmitter / receiver increases and the size of the transmitter / receiver increases, and the cost of the transmitter / receiver decreases and the size of the transmitter / receiver decreases. However, it has a drawback that it takes time to align the optical axis.

Therefore, the present invention has been made in view of the above points, and provides an optical axis aligning method for an optical wireless transmission device, which is capable of easily aligning the optical axis of the optical wireless transmission device. The purpose is.

[0006]

An optical axis aligning method for an optical wireless transmission apparatus according to the present invention includes a transmitter having at least a first optical transmitting means for transmitting a first optical signal having a narrow directivity, and A method for aligning an optical axis of an optical wireless transmission device, comprising: a receiver having a first optical receiving means for receiving a first optical signal and converting it into an electric signal, wherein the optical receiving means is provided in the receiver. The level detection means for detecting the reception level of the first optical signal received in to output the reception level signal, and the reception information corresponding to the reception level signal, on the second optical signal having a wide directivity. And a second optical transmitting means for transmitting, the transmitter has a second optical receiving means for receiving the second optical signal and extracting the received information,
In the transmitter and / or the receiver, the above-mentioned object is achieved by performing optical axis alignment according to the received information.

Further, the transmitter has display means for displaying the received information transmitted by the second optical signal received by the second optical receiving means, and based on the display output, an optical signal is output. The above-mentioned object is achieved by performing axis alignment.

Further, the transmitter has drive means for automatically scanning the optical axis of the transmitter and stopping the optical axis of the transmitter according to the received information. By automatically aligning the optical axis of the transmitter, The above-mentioned object is achieved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an optical wireless transmission device using the optical axis aligning method of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic configuration diagram showing a first embodiment of an optical wireless transmission device using the optical axis alignment method of the present invention.

In FIG. 1, first, an outline of the optical axis alignment method of the optical wireless transmission device 1 will be described. When performing optical transmission in a room or the like, the distance between the transmitting device 2 and the receiving device 3 is at most several tens of meters, so first, the light receiving element PD4 of the receiving device 3 has a relatively wide directivity. The distance is adjusted in the direction of the transmitter 2. From the transmitter 2, the video signal is converted into an optical signal and the first optical signal is output. The receiving device 3 receives the first optical signal, converts the first optical signal into an electric signal, outputs the electric signal to the outside, and detects the reception level of the first optical signal.
A pilot signal, which is a second optical signal carrying this reception level as information, is output toward the transmitter 2. Then, in the transmitter 2, the pilot signal is received by the light receiving element PD5 of the transmitter 2 and converted into an electric signal,
The reception level information is taken out, and the reception level is displayed on the level monitor 6 according to the reception level information. Therefore, the optical axis of the transmitting device 2 is adjusted while observing the receiving level information displayed on the level monitor 6, and when the receiving level displayed on the level monitor 6 becomes maximum, the optical axis alignment of the transmitting device 2 ends. Is.

As described above, according to the optical axis alignment method of the optical wireless transmission device of the first embodiment of the present invention, first,
Since the light receiving element PD4 of the receiving device 3 has a relatively wide directivity, it may be aligned with the direction of the transmitting device 2 by a certain amount. Then, since the reception level is displayed on the level monitor 6 of the transmitter 2, it is only necessary to adjust the optical axis of the transmitter 2 while watching the level monitor 6 so as to maximize the reception level. Is possible.

Next, details of the optical wireless transmission device 1 will be described. In the figure, in the transmitter 2, a video composite signal input from an external device (not shown) (VTR, for example) is sent to the carrier 1 by the video modulator 7.
It is converted into an FM-modulated wave of 0 MHz and output, and this output is converted into an optical signal, and the light emitting element LED9 is driven via the LED driver 8. The parabolic reflector 10 reflects the optical signal output of the light emitting element LED 9 into parallel light. In the receiving device 3, the optical signal is received by the light receiving element PD4 with a lens having a relatively wide directivity, the optical signal is converted into an electric signal by the light receiving circuit 11, and the signal is FM-modulated by the video demodulator 12. The video composite signal is demodulated and output as a video signal to the outside. On the other hand, the output of the light receiving circuit is also input to the level detector 13, and a reception level signal of DC output corresponding to the reception level of the received optical signal is output. Next, a VCO (voltage control oscillator) 14 generates a square wave corresponding to the reception level signal output. For example, when the applied voltage is 1v, 100Hz,
For 10v, a 1 KHz square wave is generated. And
The FM modulator 15 drives the LED 17 via the LED driver 16 as a modulated wave of carrier 1 MHz, for example, and transmits the pilot signal to the transmitter 2.

Again, in the transmitter 2, the light receiving element PD5 with a lens having a relatively wide directivity receives the pilot signal including the reception level signal output from the receiver 3. The light receiving circuit 18 converts the pilot signal into an electric signal, and the FM demodulator 19 demodulates the electric signal. The demodulated signal is converted into a DC voltage by the FV converter 20, and the reception level is displayed on the level monitor 6 via the monitor driver 21 according to the output. here,
The level monitor 6 has, for example, a configuration in which a plurality of visible LEDs are arranged, and the number of LEDs to be turned on is controlled by the monitor driver 21 according to the output of the FV converter 20. Here, the light output from the LED 9 and reflected by the parabolic reflector 10 corresponds to the above-mentioned first optical signal. The pilot signal output from the LED 17 corresponds to the above-mentioned second optical signal.

As described above, the optical wireless transmission device 1 using the optical axis aligning method of the present invention can be constructed in a small size, easily and at low cost.

Although the level monitor 6 is provided in the transmitter 2, the actual adjustment of the optical axis is not limited to the transmitter 2 side. The optical axis may be adjusted by adjusting the axis. Further, the transmitter or the receiver may be provided with an optical axis moving mechanism by a remote controller so that the optical axis can be adjusted even from a distant place. Further, by transmitting the second optical signal output from the receiving device, for example, an optical signal having an audio signal according to the reception level, the audio is transmitted,
In the transmitting device, if the received voice information is reproduced as it is and the level and quality of the reproduced sound are used as a monitor material, a simpler configuration can be achieved.

Next, another embodiment of the optical wireless transmission device using the optical axis aligning method of the present invention will be described. In addition,
The same reference numerals are used for the same or corresponding components as in the first embodiment described above, and the description thereof may be omitted. Figure 2
FIG. 6 is a schematic configuration diagram showing a second embodiment of an optical wireless transmission device using the optical axis alignment method of the present invention.

First, the outline of the optical axis alignment method of the optical wireless transmission device 31 of the second embodiment of the present invention will be described. The difference from the above-described first embodiment is that the optical axis alignment is automatically performed. In the figure, the transmitter 32 outputs a stop signal when it is detected that the output voltage of the reception level information extracted from the received pilot signal has reached a predetermined voltage or higher. Further, in the transmitter 32, the motor 34 automatically scans the optical axis. When this stop signal is detected, the scanning is stopped and the optical axis alignment is completed. That is, when the receiving device 33 obtains a sufficient reception level, the optical axis of the transmitting device 32 is automatically fixed, and this optical axis alignment ends.

As described above, according to the optical axis alignment method for the optical wireless transmission device of the second embodiment, it is possible to automatically perform the optical axis alignment on the transmitting device 32 side.

Next, details of the optical wireless transmission device 31 will be described. The difference from the above-described first embodiment is that the optical axis alignment is automatically performed. As described above, in the transmission device 32, the reception information signal extracted from the received pilot signal is converted into the DC voltage by the FV converter 20. Here, the output of the FV converter 20 is input to one input terminal of the comparator 35. On the other hand, a predetermined voltage is applied to the other input terminal of the comparator 35, and F
When the output voltage of the V converter 20 becomes equal to or higher than a predetermined voltage, that is, when the receiving device 33 obtains a sufficient reception level, the comparator output is inverted from 0 to 1. When the comparator output is 0, the motor 34 is driven via the motor controller 36, and the optical axis of the transmitting device 32 is scanned in the vertical and horizontal directions. When the comparator output becomes 1, the motor 34 is stopped via the motor controller 36, and the scanning of the optical axis of the transmitter 32 is stopped. Here, the motor 34 is, for example, a direct drive motor 34a and a linear stepping motor 34.
b), the horizontal drive of the direct drive motor 34a causes horizontal scanning, and the linear stepping motor 34b vertically feeds the shaft in steps to perform vertical scanning.

According to this structure, it is possible to provide an optical wireless transmission device for performing automatic optical axis alignment with a simple structure.

Note that, for example, the VCO 14 of the receiving device 33
If a voltage higher than a predetermined voltage is input at, the transmitter 3
When the second optical signal sent to the second optical signal is transmitted as an unmodulated carrier, and the transmitter 32 detects this, the motor 34
If the configuration is such that the stop signal is output, a simpler configuration can be achieved.

The transmitter and the receiver can be modified in various ways. The example will be described below with reference to the accompanying drawings.

FIG. 3 is a schematic configuration diagram showing a third embodiment of an optical wireless transmission device using the optical axis aligning method of the present invention. First, the outline of the optical axis alignment method of the optical wireless transmission device 41 will be described. The difference from the second embodiment is that the receiving device outputs a motor stop signal. In the figure, in the receiving device 43, the reception level voltage is compared with a predetermined voltage, and when there is an output equal to or higher than the predetermined voltage, the LED 17 is driven and a single optical signal is transmitted as a stop signal. In the device 42, when the stop signal is received, the motor 34 is stopped and the transmitter 4
The optical axis alignment of 2 is completed.

As described above, according to the optical axis alignment method for the optical wireless transmission device of the third embodiment, the optical axis alignment can be automatically performed on the transmitting device 42 side.

Next, details of the optical wireless transmission device 41 will be described. The difference from the second embodiment is that the receiving device outputs a motor stop signal. In the figure, in the receiving device 43, the comparator 44
The reception level output voltage is compared with a predetermined voltage, and when an output equal to or higher than the predetermined voltage is output, a control signal is output.
In response to this control signal, the LED 17 is driven via the LED driver 16, and an optical signal of a single frequency from the OSC (oscillator) 45 is transmitted as a stop signal. When the transmitter 42 receives the stop signal, the motor 34 is stopped via the motor controller 36, and the scanning of the optical axis of the transmitter 42 is stopped.

According to this structure, it is possible to provide an optical wireless transmission device that automatically aligns the optical axes, particularly with a simpler transmission device.

In the second or third embodiment described above, an optical axis moving mechanism or an automatic optical axis scanning mechanism is provided on the receiver side, and after aligning the optical axis on the transmitter side, Further, the optical axis may be adjusted on the receiving device side.

As described above, according to the optical axis alignment method of the present invention, the optical axis alignment can be easily performed, and the additional elements of the transmitter and the receiver of the optical wireless transmission device using the optical axis alignment are as follows. Since very few and simple ones are all right,
It is possible to reduce the cost of the optical wireless transmission device.

Note that the configurations of the transmitter and the receiver of the optical wireless transmission device described in the above embodiments are examples for explaining the technical idea of the present invention, and the configurations are appropriately changed. It is possible.

[0030]

As described above, according to the optical axis aligning method of the optical wireless transmission device of the present invention, the first optical transmitting means of the transmitter transmits the first optical signal to the receiver. Level detection means for detecting the reception level of the first optical signal received by the optical reception means and outputting the reception level signal, and reception information corresponding to this reception level signal to a second optical signal having a wide directivity. A second optical transmitting means for carrying and transmitting, and a transmitter having a second optical receiving means for receiving a second optical signal and extracting the received information, and transmitting and / or receiving Since the optical axis alignment is performed according to the received information in the receiver, the optical axis alignment can be easily performed, and an optical wireless transmission device using this optical axis alignment method can easily perform the optical axis alignment with a simple configuration. Matching can be done.

Further, the transmitter has display means for displaying the received information transmitted by the second optical signal received by the second optical receiving means, and optical axis alignment is performed based on the display output. Since the optical axis alignment can be easily performed while confirming the reception level of the receiver on the display means, the optical wireless transmission device using this optical axis alignment method can easily perform the optical axis alignment with a simple configuration. It can be performed.

Further, the transmitter has drive means for automatically scanning the optical axis of the transmitter and stopping it according to the received information.
Since the optical axis of the transmitter is automatically adjusted, the optical axis can be easily adjusted automatically on the transmitter side. An optical wireless transmission device that uses this optical axis adjustment method performs automatic optical axis adjustment with a simple configuration. be able to.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of an optical wireless transmission device using an optical axis alignment method of the present invention.

FIG. 2 is a schematic configuration diagram showing a second embodiment of an optical wireless transmission device using the optical axis alignment method of the present invention.

FIG. 3 is a schematic configuration diagram showing a third embodiment of an optical wireless transmission device using the optical axis alignment method of the present invention.

[Explanation of symbols]

 1, 31, 41 Optical wireless transmission device 2, 32, 42 Transmission device (transmitter) 3, 33, 43 Reception device (receiver) 4 Light receiving element PD (first optical receiving means) 5 Light receiving element PD (second) Optical receiving means) 6 Level monitor (display means) 8 LED driver (first optical transmitting means) 9 LED (first optical transmitting means) 11 Light receiving circuit (first optical receiving means) 13 Level detector (level Detecting means 16 LED driver (second optical transmitting means) 17 LED (second optical transmitting means) 18 Light receiving circuit (second optical receiving means) 34 Motor (driving means) 36 Motor controller (driving means)

Claims (3)

[Claims] 1. A transmitter having at least first optical transmission means for transmitting a first optical signal having a narrow directivity, and first optical for receiving the first optical signal and converting it into an electric signal. A method for aligning an optical axis of an optical wireless transmission device comprising a receiver having a receiving means, wherein the receiver detects a receiving level of the first optical signal received by the optical receiving means, and a receiving level Level detection means for outputting a signal, and reception information according to the reception level signal, having a second optical transmission means for transmitting the second optical signal having a wide directivity, the transmitter, to the transmitter. A second optical receiving means for receiving the second optical signal and extracting the received information, wherein the transmitter and / or the receiver performs optical axis alignment according to the received information. A method for aligning an optical axis of an optical wireless transmission device characterized. 2. The transmitter includes display means for displaying the received information transmitted by the second optical signal received by the second optical receiving means, and an optical signal is output based on the display output. The optical axis alignment method for an optical wireless transmission device according to claim 1, wherein the optical axis alignment is performed. 3. The transmitter includes drive means for automatically scanning the optical axis of the transmitter and stopping the optical axis of the transmitter according to the received information. The optical axis of the transmitter is automatically adjusted. The optical axis alignment method for an optical wireless transmission device according to claim 1, characterized in that.