JPH04159831A - Optical spatial transmitter - Google Patents

Abstract

PURPOSE:To receive optical beams with simple constitution and to surely receive information by arranging receivers in such a manner that the optical beam mixed through a condenser lens is not incident or other photodetector of other receiver. CONSTITUTION:This optical spatial transmitter is provided with the 1st and 2nd receivers 1 and 2. The 1st and 2nd receivers 1 and 2 are arranged so that the 2nd optical beam LA2 mixed through the 1st condenser lens 1A is not incident on the 1st photodetector element 1B and the 1st optical beam LA1 mixed through the 2nd condenser lens 2A is not incident on the 2nd photodetector 2B. Thus, information can be surely transmitted even when the plural receivers 1 and 2 are used.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to an optical space transmission device, and is particularly suitable for transmitting information using a plurality of optical space transmission lines.

B. Summary of the Invention The present invention provides an optical space transmission device with a simple configuration by arranging the receiver so that the light beam from another receiver that enters through the condenser lens does not enter the light receiving element. , information can be reliably received even when multiple receivers are installed.

C. Prior Art Conventionally, as this type of optical space transmission device, one has been proposed that transmits desired information via a light beam transmitted in space (Japanese Patent Application No. 63-13812).
No. 0).

That is, on the transmitting side, for example, a semiconductor laser is driven with a desired information signal, and a light beam output from the semiconductor laser is sent to the receiving side with a predetermined spread.

On the receiving side, on the other hand, the light beam is guided to a light receiving element through a predetermined optical system, and the output signal of the light receiving element is demodulated by a predetermined demodulation circuit.

As a result, desired information can be easily transmitted by installing transmitters and receivers facing each other between buildings, for example.

D Problems to be Solved by the Invention By the way, in this type of optical space transmission device, it is thought that by increasing the number of installed devices, the amount of information to be transmitted can be easily increased.

However, when the number of installed receivers was increased, there was a problem in that the light beams sent out to the corresponding receivers could mix into adjacent receivers, causing interference.

One way to solve this problem is to increase the distance between adjacent receivers, but in this case a wide installation space is required, and in practice it is difficult to install in a limited space such as the rooftop of a building. It will no longer be possible to install it.

On the other hand, there is a method in which the transmitter side sends out light beams with different wavelengths and receives the light beams through a filter, so that the receiver side selectively receives only the light beams with the corresponding wavelengths. Conceivable.

Another possible method is to reduce the interference by switching the modulation signal of the light beam.

However, when these methods are used, the configuration of the spectral space transmission device inevitably becomes complicated.

The present invention has been made in consideration of the above points, and aims to propose an optical space transmission device that has a simple configuration and can reliably transmit information even when a plurality of devices are installed.

8. Means for Solving the Problems In order to solve the problems, in the present invention, the first light beam LAI sent out from the first transmitters arranged to face each other is transmitted through the first condensing lens IA. a first receiver 1 that receives the transmission information transmitted via the first light beam LAI based on the output signal of the first light receiving element IB; , first receiver 1
A second light beam LA2 sent out from a second transmitter disposed close to and facing the is guided to a second light receiving element 2B via a second condensing lens 2A, A second light receiving element that receives transmission information transmitted via the second light beam LA2 based on the output signal of the second light receiving element 2B.
receiver 2, the first receiver l is installed so that the second light beam LA2 entering through the first condenser lens IA does not enter the first light receiving element IB, The first light beam LAI mixed through the two condensing lenses of
the second receiver 2 so that the light does not enter the second light receiving element 2B.
Set up.

F action The receiver is configured such that the second and first light beams LA2 and LAI entering through the first and second condensing lenses IA and 2A, respectively, do not enter the first and second light receiving elements IB and 2B. By arranging receivers 1 and 2, information can be reliably transmitted with a simple configuration even when a plurality of receivers 1 and 2 are installed.

G example An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, numerals 1 and 2 each indicate a bidirectional optical space transmission device, which transmits and receives desired information to and from an optical space transmission device (not shown) placed opposite to each other.

That is, the optical space transmission device 1 drives a semiconductor laser with a desired information signal, and transmits the resulting light beam to the lens I.
Inject via A.

Thereby, the optical space transmission device 1 is configured to send out a light beam with a predetermined spread toward the optical space transmission device to be transmitted.

Furthermore, the optical space transmission device 1 receives the light beam LAN arriving from the transmission target via the lens IA, and focuses the light beam LAX on the light receiving element IB.

Furthermore, the optical space transmission device 1 demodulates the output signal of the light receiving element IB with a predetermined signal processing circuit, thereby receiving a desired information signal sent from the transmission target.

Similarly, the optical space transmission device 2 sends out a light beam modulated with an information signal towards the optical space transmission device to be transmitted, and also directs the light beam LA2 coming from the transmission target to the lens 2.
A receives the light beam LA2, and focuses the light beam LA2 on the light receiving element 2B.

As a result, the optical space transmission device 2
The desired information is transmitted and received between the transmission target and the transmission target.

Furthermore, in this embodiment, the optical space transmission devices 1 and 2 are arranged such that the light beams LA arriving at the optical space transmission devices 1 and 2 are
I and LA2 are arranged so as to intersect with each other, so that the optical space transmission devices 1 and 2 are arranged close to each other, so that information can be reliably received.

That is, if the optical space transmission devices 1 and 2 are arranged so that the light beams LAI and LA2 intersect, the optical space transmission device 1
Compared to a case where the positions of LAI and LA2 are swapped and the light beams LAI and LA2 do not intersect, the spatial optical transmission device f1 can increase the incident angle θ1 of the light beam LA2 with respect to the optical axis.

Similarly, the optical space transmission device 2 has a light beam LA as the optical axis.
The incident angle θ2 of I can be increased.

In this state, the optical space transmission devices 1 and 2 are connected to the condenser lens IA.
The focal paths #fl and f2 of IB and IB are selected so as to satisfy the following relational expression (1).

Here, dl and d2 are light receiving elements IB and 2B, respectively.
Δx1 and Δx2 are the radius of the light beam LA from the optical axis.
2 and the distance to the LAN focal point.

That is, in the optical space transmission devices 1 and 2, the light beam LA2 is condensed through the lens IA and the two persons, respectively.
and LAI are prevented from entering the light receiving elements IB and 2B.

In this way, in the optical space transmission bags W1 and 2,
Harmful light beams LA2 and LAI are removed from lenses IA and IB
Even if the light beams LA2 and LAI are mixed in through the light receiving elements IB and 2B, only the corresponding light beams LAX and LA2 can be selectively received.

Therefore, interference by the light beams LA2 and LAl can be easily and effectively avoided by simply selecting the installation positions of the optical space transmission devices ff and 2, and thereby the optical space transmission devices 1 and 2 are placed close to each other. However, you can reliably receive the desired information.

In the above configuration, the light beam sent out from the optical space transmission device 1 is received by the optical space transmission device to be transmitted, thereby allowing the optical space transmission device 1 to transmit desired information.

On the other hand, the light beam LAN sent out from the optical space transmission device to be transmitted illuminates the optical space transmission devices 1 and 2 with a predetermined spread.
The light beam LAN incident on the light receiving element IB is focused on the light receiving element IB.

Thereby, the optical space transmission device 1 can receive the information sent from the transmission target.

On the other hand, the light beam LAI- incident on the lens 2A of the optical space transmission device 2 is focused at a position separated by a distance Δχ2 from the light receiving element 2B.

Similarly, the light beam sent out from the optical space transmission device 2 is
The light is received by the optical space transmission device to be transmitted, and thereby the desired information can be transmitted from the optical space transmission device 2.

On the other hand, the light beam LA2 sent out from the optical space transmission device to be transmitted irradiates the optical space transmission devices 1 and 2 with a predetermined spread.
The light beam LA2 incident on the light receiving element 2B is focused on the light receiving element 2B.

As a result, in the optical space transmission device 2, the light beam LA
2 is received by the light receiving element 2B, interference with the light beam LAI can be effectively avoided, and the information transmitted from the transmission target can be reliably received.

On the other hand, the light beam LA2 incident on the lens IA of the optical space transmission device 111 is focused at a position separated by a distance Δxi from the light receiving element IB, and thereby the optical space transmission device f
In No. 1, only the light beam LAI is received by the light receiving element IB, and interference with the light beam LA2 can be effectively avoided and information can be reliably transmitted.

According to the above configuration, the optical spatial transmission bag W1 and 2, it is possible to receive only the corresponding light beams LAI and LA2 with a simple configuration, and thus information can be reliably received even if they are installed close to each other.

In the above-mentioned embodiment, a case was described in which two sets of optical space transmission devices were installed, but the present invention is not limited to this, and can be widely applied to cases in which a plurality of optical space transmission devices are installed as necessary.

At this time, for example, as shown in FIG.
When arranging A to 4D and 5A to 5D facing each other, each optical space transmission bag! The optical space transmission devices 5A to 5D on the receiving side may be arranged according to the spread of the light beams emitted from the light beams 4A to 4D. If the light beams are not incident, the light beams may not intersect.

Furthermore, in the above-described embodiment, a case was described in which a plurality of optical space transmission devices were installed, but the present invention is not limited to this, and as shown in FIG. 3, a condenser lens may be shared. good.

That is, the light beam LA1 incident on the condenser lens 6 is condensed onto the light receiving element 7A arranged on the optical axis.

On the other hand, a light receiving element 7B is arranged at a position separated by a predetermined distance from the optical axis, and the light beam LA2 incident on the condenser lens 6 at a predetermined angle is focused on the light receiving element 7B.

In this way, since the condensing lens 6 is shared, the overall configuration can be simplified, and at this time, mutual interference between the light beams LAI and LA2 can be effectively avoided and information can be received reliably. .

Further, in the above-described embodiments, a case has been described in which the present invention is applied to a bidirectional optical space transmission device, but the present invention is not limited to this, and the present invention is not limited to this. Can be widely applied.

H Effects of the Invention As described above, according to the present invention, by arranging the receiver so that the light beam of another receiver that enters through the condenser lens does not enter the light receiving element, a simple configuration can be achieved. Thus, it is possible to obtain an optical space transmission device that can receive only the corresponding light beam at the receivers and can reliably receive information even if the receivers are installed close to each other.

[Brief explanation of the drawing]

FIG. 1 is a route map showing an optical space transmission device according to one embodiment of the present invention, and FIGS. 2 and 3 are route maps showing other embodiments. 1.2.4A to 4D, 5A to 5D... Optical space transmission device, IA, 2A, 6... Lens, IB, 2
B, 7A, 7B... Light receiving element. Hikari 1 Dodan im p sword comb [place ^--1μm ↑death l)'] ζjfj ida'1 Fig. 2 en'z koi (I column

Claims (2)

[Claims] (1) A first light beam sent out from a first transmitter arranged to face each other is guided to a first light receiving element via a first condensing lens, and a first receiver configured to receive transmission information transmitted via the first light beam based on an output signal; guiding the second light beam sent out from the second transmitter to the second light receiving element via the second condensing lens;
A second light receiving element that receives transmission information transmitted via the second light beam based on the output signal of the second light receiving element.
a receiver, the first receiver is installed so that the second light beam entering through the first condensing lens does not enter the first light receiving element, 1. An optical space transmission device characterized in that said second receiver is installed so that said first light beam mixed in through said second condenser lens does not enter said second light receiving element. (2) The first and second receivers are connected to the first and second receivers.
An optical space transmission device characterized in that a condenser lens is shared.