JPH0119481Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an improvement in an optical signal transmitter/receiver that constitutes an optical communication system that performs spatial transmission of information using light.

(Prior art) Conventionally, information in an electrical signal is converted into an optical signal and transmitted by an optical transmitter, and this optical signal is received by an optical receiver, converted into an electrical signal, and then supplied to an information processing system such as a computer. Optical communication systems exist.

This conventional device has a schematic structure as shown in FIG. That is, in the figure, 1 is an optical transmitter, 2 is a casing that serves as its frame, 3 is a light emitting circuit that is an electro-optical modulation circuit, 4 is a light emitting element such as an LED, and 5 is mainly composed of a lens. It is an optical system, and 6 is an optical receiver, 7 is a housing that serves as its frame, 8 is a light receiving circuit that is an optical-electrical demodulation circuit, 9 is a light receiving element such as a photodiode, and 10 is mainly composed of a lens. This is an optical system that can be used. The optical systems 5 and 10 are provided to make the transmission distance as long as possible, and l ₀ is their optical axis. Further, Ein is an electrical input signal, Eout is an electrical output signal, and L _p is an optical signal.

By the way, when performing one-way communication using this device, it is sufficient to install one optical transmitter 1 and one optical receiver 6, as shown in Fig. 1, but when performing two-way communication, As shown in Fig. 2, two optical transmitters 1 and two optical receivers 6 are installed in the system, so the optical communication systems in both directions are optically separated from each other so that their optical axes l can be Since the installations must be staggered and electrical signal processing systems must be installed for each, the system becomes larger and requires adjustment of the two optical axes, making it difficult to adjust the optical axes. The actual situation is that it causes various problems such as becoming complicated.

(Purpose of the invention) The present invention was made in view of the problems of the above-mentioned prior art, and its purpose is to improve performance, make the system more compact, simplify its configuration, etc. It is an object of the present invention to provide an optical signal transmitter that can constitute an extremely excellent, especially bidirectional optical communication system.

(Structure of the invention) In order to achieve the above object, the present invention has the following structure.

That is, a bifocal lens having two focal points on the same optical axis is attached to the front of the housing, and
In the part of the housing behind the bifocal lens,
A front support and a rear support are attached, the front support is formed from a convex lens and placed at one focal position of the bifocal lens, and the rear support is connected to the bifocal lens. A light emitting element positioned at the one focal point and a light receiving element configured to transmit an optical signal and a light receiving element configured to receive the optical signal are disposed at the other focal point combined with the front support. one side is supported, and the rear support body includes:
An optical signal transmitter/receiver characterized in that either the light emitting element or the light receiving element is supported by being positioned at the other focal point.

(Embodiments) Hereinafter, the present invention will be described in detail with reference to illustrated embodiments.

FIG. 3 shows a first embodiment of the present invention. In the figure, 11 is an optical transceiver of the present invention, and 12 is a housing serving as a frame thereof. Inside this housing 12, two bifocal lenses 13, 14, a front support 15, and a rear support 16 are arranged. The bifocal lenses 13 and 14 are arranged so that they have the same optical axis, _l1 is the optical axis, and these bifocal lenses 13 and 1
4 to form two focal points. The front support 15 is arranged behind the bifocal lenses 13 and 14 so that its center is on the optical axis _l1 , and is movable back and forth along the optical axis _l1 . It is formed by a convex lens. An optical system 17 having two focal points f 1 and _{f 2} on the same optical axis l ₁ by this front support 15 and the two bifocal lenses 13 and 14
is configured.

A light emitting element 18 is fixed to the center of the front support 15, and 18A is a light emitting part thereof. As this light emitting element 18, a light emitting diode is mainly used. This light emitting element 18 is positioned so that the highest luminous intensity part of its light emitting part 18A is on the focal point _f1 , and transmits an optical signal _L1 through the bifocal lenses 13 and 14 in the optical system 17. 18B is a lead connected to the electrical signal transmission circuit system (not shown).

The rear support member 16 is arranged behind the front support member 15 so that its center portion is on the optical axis _l1 , and is capable of reciprocating movement along the optical axis _l1 . A light-receiving element 19 is fixed at the center of the rear support 16, and 19A is a light-receiving portion of the light-receiving element 19. As the light-receiving element 19, a photodiode, a phototransistor, or the like is mainly used. This light-receiving element 19 is positioned so that its light-receiving portion 19A is on the focal point _f2 , and receives an optical signal from a light-emitting element 18' of an optical transceiver 20, which will be described later.
It is assumed that L ₂ is received through the optical system 17. 19B is a lead connected to an electric signal receiving circuit system (not shown) of this light receiving element 19.

The optical transceiver 20 is a modified version of the present invention that constitutes a two-way optical communication system together with the optical transceiver 11 described above, and has the same components as the optical transceiver 11, so it is a modification of the present invention. The same reference numerals are given the same symbol with a ``', and the explanation thereof will be omitted, and only the different parts will be explained.

First, a bifocal lens 21 is disposed at the frontmost part of the housing 12' so that its optical axis is on the optical axis _l1 , and the front support 15' is attached to the bifocal lens 21.
The front support 15' and the bifocal lens 21 are disposed on the same optical axis behind the lens 1.
Thus, an optical system 22 having two focal points f ₃ and f ₄ on the optical axis l ₁ is configured. The light emitting element 18' is fixed to the center of the rear support 16', and its position is adjusted so that the highest luminous intensity part of the light emitting part 18'A is on the focal point _f4 , and an optical signal is transmitted through the optical system 22. It is supposed to transmit L ₂ . Light receiving element 1
9' is fixed to the center of the front support 15', and its position is adjusted so that its light receiving part 19'A is on the focal point _f3 , and the bifocal lens 21 of the optical system 22
The optical signal _L1 from the light emitting element 18 of the optical transceiver 11 is received through the optical transmitter/receiver 11. In addition, in the figure,
Ein1, Ein2 are electrical input signals, Eout1, Eout2
is the electrical output signal.

The bidirectional optical communication system configured as described above operates as follows. That is, first, the electric _signal Ein1 input through the lead 18B is converted into an optical signal L1 by the light emitting element 18 and emitted, and this optical signal _L1 is transmitted to the bifocal lenses 14 and 13.
The parallel light is made into parallel light and enters the bifocal lens 21 of the optical transmitter/receiver 20. And the optical signal L ₁
is refracted by the bifocal lens 21 and focused on the light receiving portion 19'A (focal point f ₃ ) of the light receiving element 19', and the electric signal Eout1 is transmitted by this light receiving element 19'.
and is output to an electrical signal receiving circuit system (not shown). On the other hand, the electric signal Ein2 input through the lead 18'B is converted into an optical signal _L2 by the light emitting element 18' and emitted, and this optical signal _L2 is received by the front support 15 at its center. The parallel light beam is cut by the element 19' and is turned into a ring-shaped parallel beam that surrounds the optical path of the optical signal _L1 , and enters the bifocal lens 13 of the optical transceiver 11. The optical signal L ₂ is then transmitted to the bifocal lens 1
3, 14 and the support 15, the light is focused on the light receiving portion 19A (focal point f ₂ ) of the light receiving element 19, and is converted by the light receiving element 19 into an electrical signal Eout2, which is sent to an electrical signal receiving circuit system (not shown). This is what is output to.

According to the above embodiment, in the case of the optical transceiver 11, the front support 15 is moved, while in the case of the optical transceiver 20, the front support 15' and the rear support 16' are moved. As a result, the directivity of the optical signals L ₁ and L ₂ can be changed depending on the distance between the two optical transceivers 11 and 20, making it possible to perform two-way communication with multiple devices installed at different locations. . Of course, one-way communication with the conventional configuration shown in FIGS. 1 and 2 is also possible. Furthermore, by moving the light receiving elements 19, 19', their sensitivity can be easily adjusted, and the output can be adjusted according to the communication distance. Also, this can be said about both optical transceivers 11 and 20,
Taking the optical transmitter/receiver 11 as an example, as shown by the broken line arrow in FIG. Since the light is incident on the light receiving element 19, it is possible to check whether the transmission is being performed reliably based on its output. Furthermore, since the front supports 15 and 15' are formed of lenses, the rear focal length of the optical systems 17 and 22 can be shortened.
Front supports 15, 15' and rear supports 16, 1
6' can be shortened, making it more compact.

FIG. 5 shows a second embodiment of the present invention, and its feature is that a two-way optical communication system is constructed using optical transceivers with the same configuration. Unlike the first embodiment shown in FIG. 3, the optical signals involved in transmission and reception are not parallel lights but scattered lights.

In the figure, the optical transceivers 23 and 23' are the optical transceivers of the present invention.
23' have the same configuration, the configuration of the optical transceiver 23 will be explained here, and the same components will be marked with "'" and their explanation will be omitted.
Reference numeral 24 denotes a housing serving as a frame, and inside this housing 24, a bifocal lens 25, a front support member 26, and a rear support member 27 are arranged. l ₂ is the optical axis of the bifocal lens 25, and the front support 26 is arranged behind the bifocal lens 25 so that its center is on the optical axis l _{2 .} It is movable back and forth along the lens, and is formed by a lens.
The front support 26 and the bifocal lens 25 constitute an optical system 28 having two focal points f ₅ and f ₆ on the optical axis l ₂ .

A light emitting element 29 is fixed to the center of the front support 26, and 29A is the light emitting part thereof. This light emitting element 29 is positioned so that the highest luminous intensity portion of its light emitting portion 29A is located near the focal point _f5 , and an optical signal _L3 , which is a diverging light, is transmitted through the bifocal lens 25 in the optical system 28. shall be sent,
29B is a lead connected to the electrical signal transmission circuit system (not shown).

The rear support body 27 is arranged behind the front support body 26 so that its center is on the optical axis _l2 , and is capable of reciprocating movement along the optical axis _l2 . A light-receiving element 30 is fixed to the center of the rear support 27, and 30A is its light-receiving portion. The position of this light receiving element 30 is adjusted so that its light receiving portion 30A is located near the focal point _f6 ,
Optical signal from light emitting element 29' of optical transceiver 23'
L ₄ is supposed to be received through the optical system 28. 30B is a lead connected to an electrical signal receiving circuit system (not shown) of the light receiving element 30. In addition, Ein3 and Ein4 are electrical input signals, Eout3,
Eout4 is an electrical output signal.

In the second embodiment with the above configuration, the light emitting element 29 is provided on the front support 26, so if a light emitting diode is used as the light emitting element 29,
Emitted light can be used efficiently and good optical communication becomes possible. This is because the light emitting intensity of the light emitting diode is strongest at its center, so if the light emitting diode is provided on the rear support 27, the light emitted from the center will be transmitted to the front element (light receiving element).
This is because it is cut and weakened even by The other effects are approximately the same as those of the first embodiment shown in FIG. 3, so their explanation will be omitted here.

In addition, if direct optical communication is not possible due to an obstacle between communication stations, multiple communication systems may be installed, and a relay amplifier or the like may be installed between the communication systems to enable optical communication. It is something that can be done.

(Effects of the invention) As is clear from what has been described above, according to the invention, the spacing between the light emitting element and the light receiving element can be adjusted by the combination of the bifocal lens and the front support consisting of the convex lens. As a result, it is possible to realize an extremely compact optical signal transmitter/receiver that has both transmitting and receiving functions.
This provides an advantageous effect when applied to a two-way optical communication system.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a conventional unidirectional optical communication system. FIG. 2 is a schematic configuration diagram of a conventional two-way optical communication system. FIG. 3 is an operation explanatory diagram showing a schematic configuration of a first embodiment of a bidirectional optical communication system constructed using the optical transceiver of the present invention. Figure 4 shows
FIG. 4 is an operation explanatory diagram showing an enlarged view of one side of the optical transceiver shown in FIG. 3; FIG. 5 is an operation explanatory diagram showing a schematic configuration of a second embodiment of a bidirectional optical communication system constructed using the optical transceiver of the present invention. 11, 20, 23, 23'...optical transceiver, 1
7, 22, 28, 28'...Optical system, 18, 1
8', 29, 29'... Light emitting element, 19, 19',
30, 30'... Light receiving element, l ₁ , l ₂ ... Optical axis, L ₁ ,
L ₂ , L ₃ , L ₄ ... optical signal, f ₁ , f ₂ , f ₃ , f ₄ , f ₅ , f ₅ ',
f ₆ , f ₆ ′...Focus.

Claims (1)

[Scope of utility model registration request] A bifocal lens having two focal points on the same optical axis is attached to the front part of the housing, and a front support member and a rear support member are attached to the part of the housing that is behind the bifocal lens. the front support is formed from a convex lens and placed at one focal position of the bifocal lens, and the rear support is the other formed by the bifocal lens and the front support; The front support is positioned at the one focal point and supports either a light emitting element that transmits an optical signal or a light receiving element that receives an optical signal, and the rear support The optical signal transmitter/receiver is characterized in that the other of the light emitting element and the light receiving element is supported by being positioned at the focal point of the other.