JPH01217404A - Optical space transmitting equipment - Google Patents

Abstract

PURPOSE:To simplify the constitution of the title equipment and to reduce the optical loss of transmitting and receiving light due to the division of an optical axis by guiding light through a light transmitting part or light reflecting part of a mirror and a converging optical element to be used for both transmission and reception. CONSTITUTION:The equipment has an optical information transmitting light emitting element 5, an optical information receiving light receiving element 9, the mirror provided with the light reflecting part 25b and the light transmitting part 25a, and the transmitting/receiving converging optical element 3. Transmitting light projected from the element 5 is sent to an optical space transmission route 8 successively through the light transmitting part 25a of the mirror 5 and the element 3 and receiving light transmitted through the transmission route 8 is made incident on the element 9 successively through the element 3 and the light reflecting part 25b of the mirror 25. Consequently, the constitution can be simplified, and even when a lens 3 is used for both transmission and reception in common, optical loss due to optical axis direction can be extremely small.

Description

[Detailed description of the invention] The present invention will be explained in the following order.

A Industrial field of application B Overview of the invention C Prior art D Problem to be solved by the invention E Means for solving the problem (Fig. 1) F Effect G Embodiment G1 First embodiment (Fig. 1) ) G2 Second Embodiment (Fig. 2) G3 Third Embodiment (Fig. 3) G4 Fourth Embodiment (Fig. 4) The present invention relates to an optical space transmission device that transmits and receives optical information using an optical space transmission line.

B. Summary of the Invention The present invention relates to an optical space transmission device, in which transmitted light emitted from a light emitting element for transmitting optical information is sequentially passed through a light transmitting part (or a light reflecting part) of a mirror and a converging optical element used for transmitting and receiving,
The received light transmitted through the optical space transmission line is sent to the optical space transmission line, and the received light is sequentially passed through the transmitting/receiving converging optical element and the light reflecting part (or light transmitting part) of the mirror to receive optical information. By making the light incident on the light-receiving element, the structure is simple, the optical loss of the transmitted light and the received light due to optical axis division is small, and the assembly work of the apparatus is facilitated.

C. Conventional technology As an optical space transmission device for optical communication between two remote points,
Conventionally, there is a parallel two-axis type in which the light transmitting system and the light receiving system are provided separately, and separate lens barrels in which the light transmitting system and the light receiving system are housed are arranged in parallel, but this requires a large device. In addition, an adjusting means for adjusting the parallelism between both lens barrels is required, and the apparatus becomes complicated.

Therefore, if the light transmitting system and the light receiving system are configured coaxially, the above-mentioned problems can be solved.

Next, a reference example of a coaxial type optical space transmission device will be described with reference to FIG. (1) is a lens barrel, inside of which there is a light emitting element (5) for transmitting optical information and a light receiving element (9) for receiving optical information.
A half mirror (10) for splitting transmitting and receiving light is provided, and a transmitting and receiving common lens (3) is provided at the aperture of the lens barrel (1).
).

The divergent transmitted light L1 from the light emitting element (5) is incident on the transmitting/receiving common lens (3) through the half mirror (10), and the substantially parallel transmitted light L1 emitted from this is transmitted through the optical space transmission line (8). and is received by the other party's optical space transmission device.

Further, the substantially parallel received light L2 from the other device, which has been transmitted through the optical space transmission line (8), enters the transmission/reception common lens (3), and the convergent received light L2 emitted from this is as follows. After being reflected by the half mirror (10), the light is incident on the light receiving element (9). The received light L2 incident on the light receiving element (9) is converted into an electrical signal there.

However, the optical space transmission device as shown in FIG.
Due to the insertion loss of the half mirror (10), the transmitted light LL
The S/N of the transmitted light L1 and the received light L2 decreases due to the loss of both the received light L2 and the generation of stray light due to the half mirror (10) in the lens barrel (1), making long-distance communication difficult. Become.

Therefore, the present applicant previously proposed an optical space transmission device as Utility Application No. 62-28483, which has a simple configuration and is capable of increasing the transmission efficiency and S/N of each of the transmitted light and the receiving destination.
(Unknown prior to filing of this application) was proposed.

Below, such an optical space transmission device (first prior example) (a coaxial type optical space transmission device, the same applies to the second and third prior examples) will be described with reference to FIG.

(1) is a lens barrel, and each optical element described below is arranged inside the lens barrel and in an opening provided therein.

(5) is a light emitting element for transmitting optical information, such as a laser diode, which is attached to the lower surface of the lens barrel (1) and placed inside the sealed case (15). Note that the transmitted light L1 from the light emitting element (5) can be any visible light, infrared light, or the like. (6) is the divergent transmitted light L from this light emitting element (5)
1 is a convex lens for transmission, and is similarly placed inside a sealed case (15). (9) is a light-receiving element for receiving optical information, such as a photodiode, and is attached to one end surface of the lens barrel (1). (4
) is a light-receiving lens that converges the received light and makes it enter the light-receiving element (9), and is a convex lens.

(3) is a transmitting/receiving lens, which is a convex lens with a large aperture and an aspherical lens with little spherical aberration (for example, a diameter of 15 mm).
0 m1 and a focal length of 250 mm). This transmitting/receiving lens (3) is attached to an opening (18) bored in the other end surface of the lens barrel (1). (2) is a transmitting/receiving light splitter, which is composed of a bundle (2A) with a diameter of, for example, about 2 mm, which is made by bundling a plurality of thin optical fibers with a diameter of, for example, about 0.1 mm. Both end surfaces T1 and T2 of this bundle (2A) form a plane perpendicular to its axial direction. (7) is a transmitting optical element that guides the transmitted light from the light emitting element (5) to the transmitting/receiving lens (3), and is an optical fiber. A transmitting/receiving lens (3) faces one end surface of the bundle (2A), that is, the end surface T1 on the optical space transmission line side,
A bundle (2) in or near the focal plane (3a) of the lens (3) and on or near the optical axis of the lens (3).
It is arranged so that the end surface T1 of A) is located. A negative end face (7a) is located approximately at the center of the end face T1 of the bundle (2A), and one end of the transmission optical fiber (7) is connected to the bundle (2A) along the approximately center thereof. The other end is bundled so that it becomes part of the bundle (2A
) is pulled out to the outside, and the sealed case (15
), and the other end surface (7b) is opposed to the transmitting lens (16). A rubber backing (17) is attached to this opening (16), and the light other than the light that is incident on the transmission optical fiber (7) out of the transmitted light L1 from the light emitting element (5) is protected from the sealed case (16). 13) to prevent leakage. Further, the other end surface T2 of the bundle (2A) is opposed to the receiving lens (4).

Next, the operation of this optical space transmission device will be explained.

The transmitted light (divergent light) Ll from the light emitting surface (5a) of the light emitting element (5) for transmitting optical information is converged by the transmitting lens (6), and is transmitted to the other end surface (7) of the transmitting optical fiber (7).
b), thereby guided with low loss to one end surface (7a), and from that one end surface, that is, approximately the center of the optical space transmission line side end surface T1 of the bundle (2A), toward the transmitting/receiving lens (3). It emits light as if it is diverging. This divergent transmission light L1 is made into substantially parallel light by the transmitting/receiving lens (3), is emitted to the optical space transmission path (8), is transmitted, and is received by the other party's optical space transmission device.

Further, the substantially parallel received light L2 transmitted from the optical space transmission device on the other side and transmitted through the optical space transmission line (8) is incident on the transmitting/receiving lens (3) and is converged. The bundle (2
A) and is guided by the bundle (2A).

Then, the divergent received light L2 emitted from the light receiving element side end surface T2 of the bundle (2A) enters the receiving lens (4), and the convergent received light L2 is transmitted to the light receiving surface (9a) of the light receiving element (9).
). And this light receiving element (
The received light L2 incident on 9) is converted into an electrical signal there.

By the way, the transmitting/receiving lens (3) actually has some aberration (spherical aberration), and in that case, the following problem occurs. This will be explained with reference to FIGS. 7 and 8. Considering the aberration of this lens (3), the convergent received light L2 exiting the lens (3) and heading toward the bundle (2A) enters the bundle (2A) so as to form a somewhat large beam spot on the end surface T1.

In FIG. 7, the left side shows one optical space transmission device (sending side), and the right side shows the other optical space transmission device (receiving side). Here, the bundle of the left optical space transmission device ( 2A) center of end face T1 [transmission optical fiber (7)
The light is emitted in a diverging manner from the end face (7a) of The received light L2 enters the spatial transmission device.

The received light L2 that has entered the transmitter/receiver lens (3) of the optical space transmission device on the right side is thereby converged and enters the end surface T1 of the bundle (2A). In this case, the beam spot narrowed down by the focal plane (3a) of each transmitting/receiving common lens (3) of the left and right optical space transmission devices becomes a circle of confusion having a certain size area.

Therefore, as shown in Fig. 8, the transmitting/receiving lens (3)
The diameter D1 of the circle of least confusion created by and the bundle (
If both the transmitter/receiver lens (3) and the bundle (2A) are selected so that the diameter D2 of the effective light receiving surface of 2A) is approximately equal, the received light L incident on the transmitter/receiver lens (3)
2 can be efficiently incident on the light receiving element (9°).

According to such an optical space transmission device, since the transmitting/receiving lens (3) can be used in common for the transmitted light L1 and the received light L2, the configuration becomes simple. Moreover, even if the lens (3) is used for both transmission and reception, the optical loss caused by the optical axis division is extremely small. Moreover, the receiving light L2 can be efficiently made incident on the light receiving element (9) by the transmitting/receiving splitter (2) made of the optical fiber bundle (2A). Furthermore, the bundle (2
The optical fiber (7), which is partially integrated with A), can efficiently send out the transmitted light L2 to the optical transmission line (8), and can also connect the light emitting element (5) and the light receiving element (9). Since the degree of freedom in arrangement is increased, mutual light shielding can prevent a decrease in the S/N of the transmitted light L1 and the received light L2 due to stray light. Furthermore, the receiving optical axis is a bundle of optical fibers (2
A) Since it has a certain cross-sectional area, the transmitting and receiving lens (
Even if an inexpensive transmitting/receiving lens (3) whose spherical aberration is not so small that the circle of least confusion of the beam narrowed down by 3) is about the same as the cross-sectional area of the bundle (2A) is used, it is difficult to improve the light receiving efficiency of the received light L2. It can be made higher.

In this prior example, a small portion of the transmitted light L1 is reflected by the transmitting/receiving lens (3), and the reflected light may generate stray light inside the lens barrel (1), as shown in Fig. 5. This is much smaller than the stray light that occurs when a half mirror is used.

Furthermore, in the case of this prior example, only a very small amount of the stray light generated within the lens barrel (1) enters the bundle (2A). Further, by applying an anti-reflection coating to the transmitting/receiving lens (3), stray light can be reduced to 1% or less of that without anti-reflection coating, and -layer stray light is reduced. Therefore, it can be said that this prior example has almost no problem with stray light.

Note that the number of transmission optical fibers (7) located approximately at the center of the bundle (2A) is not limited to one, but may be two or more. A corresponding light emitting element may also be provided.

Also, the cross-sectional area of the transmission optical fiber (7) is the same as the handle (2).
Since it is approximately 1/400 of the cross-sectional area of A), the received light L
The degree of interference caused by this transmission optical fiber (7) of 2 is extremely small.

By the way, although such an optical space transmission device has the above-mentioned advantages, it also has the following drawbacks. That is, since the transmitting optical fiber (7), which is part of the optical fiber bundle (2A) constituting the transmitting/receiving optical splitter (2), must be twisted and pulled out, processing work for this purpose is required. In addition, the transmitting/receiving light splitter (2) has a complicated shape, which makes assembly work of the device and its maintenance and inspection work troublesome.

Therefore, the present applicant proposed an optical space transmission device (unknown prior to the filing of the present application) which improved this drawback as U.S. Pat. No. 62-149150.

Below, such an optical space transmission device (second prior example) will be explained with reference to FIG. 9. In FIG. 9, parts corresponding to those in FIG. 6 are designated by the same reference numerals, and redundant explanation will be omitted. Further, illustration and description of the lens barrel in which the optical system is housed will be omitted. (11) is an optical transparent plate for dividing transmitting and receiving light, and a transmitting and receiving common lens (for example, diameter 145 mm) (
3) and the receiving lens (4), and on the same optical axis and in the focal plane approximately 100 mm to 300 mm away from the transmitting/receiving lens (3).

A through hole (IIA) is bored in the center of this transparent plate (11), and a transmission optical fiber (13) is inserted into the through hole (IIA).
One end of the two is fitted and supported. The transmitting optical fiber (13) is then drawn out to the outside so as to cross the optical path of the received light L2 that has passed through the transparent plate (11) toward the receiving lens (4). (13A) is a protective film of this transmitting optical fiber (13), but it is removed in the part that crosses the optical path through which the receiving light L2 passes, and the outer diameter is made thinner so that it can receive as little light as possible. This is done so that it does not interfere with the passage of light L2. Incidentally, the diameter of the beam spot of the received light L2 incident on the transparent plate (11) is 1 mn+
On the other hand, the outer diameter of the protective film (13A) of the transmission optical fiber (13) is 0.9 mm, and the outer diameter of the cladding is 0.9 mm.
．． 125 mm, by removing the protective film (13A) from the transmitting optical fiber (step 3), the received light L2
The efficiency of incidence on the light receiving element (9) can be significantly improved.

Next, the operation of this optical space transmission device will be explained.

Transmission light (divergent light) L from the light emitting element (5) for transmitting optical information
l is converged by the transmitting lens (6),
The light enters and is guided by the other end of the transmission optical fiber (13), and is emitted from one end, that is, the transparent plate (11), toward the transmission/reception lens (3) in a diverging manner. The divergent transmission light L1 is made into substantially parallel light by the transmitting/receiving lens (3), is emitted to the optical space transmission line (8), is transmitted, and is received by the optical space transmission device on the other side.

Further, the substantially parallel received light L2 transmitted from the optical space transmission device on the other side and transmitted through the optical space transmission line (8) is incident on the transmitting/receiving common lens (3) and converged, and is made transparent. It focuses at the plate (11) and then diverges. The diverging received light L2 is incident on the receiving lens (4), is converged, and is incident on the light receiving element (9) in a focused manner. The received light L2 incident on the light receiving element (9) is converted into an electrical signal there.

According to such an optical space transmission device, since the transmitting/receiving lens (3) can be used in common for the transmitted light L1 and the received light L2, the configuration becomes simple. Moreover, even if the lens (3) is used for both transmission and reception, the optical loss caused by the optical axis division is extremely small. Since the degree of freedom in arrangement of the light emitting element (5) and the light receiving element (9) is increased, mutual light shielding can prevent a decrease in the S/H of the transmitted light L1 and the received light L2 due to stray light.

Furthermore, since the transmitted and received light is divided by the transparent plate (11), the configuration becomes even simpler, and the assembly and maintenance work of the device becomes easier. Furthermore, the transparent plate (11) allows the received light L2 to be efficiently incident on the light receiving element (9). Furthermore, the through hole (II) of the transparent plate (11)
A) by the transmission optical fiber (13) fitted to
The transmitted light L2 can be efficiently sent to the optical space transmission line (8).

In the optical space transmission device shown in Fig. 9, the transmission optical fiber (13
) is fitted into the through hole (IIA) of the transparent plate (11) and supported, but the present invention is not limited to this, and instead of the transparent plate (11) as the supporting member in FIG.
As in the third prior example shown in FIG. 10, a circular ring (21) is provided, and three transparent or opaque supporting parts (22) extending toward the center thereof are formed, and the intersections of the circular ring (21) are formed. A fitting portion (23) may be formed in the portion, and the end portion of the transmission optical fiber (13) may be fitted into and supported by the fitting portion (23). In short, any shape or structure may be used as long as the end of the transmission optical fiber (13) is fixed at a predetermined position.

Moreover, in the optical space transmission device shown in FIG. 9 (FIG. 6 is also possible),
If the transmitted light L1 from the light emitting element (5) can be made to enter the transmitting optical fiber (13) with sufficient energy, the transmitting lens (6) can be omitted.

D Problems to be Solved by the Invention Incidentally, in each of the above-mentioned prior examples, the transmitted light L1 from the light emitting element for transmitting optical information (5) is transmitted to the transmitting/receiving light splitter (2) or the transparent plate (11). Since the transmission optical fiber (7) or (13) is used to guide the
3), the protective film (7a) or (13a) is removed from the transmitting/receiving light splitter (2) or the transparent plate (11) to prevent the receiving light L2 from passing through the transmitting/receiving lens (3). Since the attempt is made to reduce interference, there is a drawback that assembly of the device is troublesome.

In view of these points, the present invention seeks to propose an optical space transmission device that has a simple configuration, has little optical loss of transmitted light and received light due to optical axis splitting, and is easy to assemble. .

E. Means for Solving the Problems The optical space transmission device of the present invention includes a light emitting element for transmitting optical information (5), a light receiving element for receiving optical information (9), a light reflecting part (25b) and a light transmitting part ( mirror (25a) with
5) and a convergent optical element (3) for transmitting and receiving, and transmits the transmitted light emitted from the light emitting element (5) for transmitting optical information to the light transmitting part (25a) (or light reflecting part) of the mirror (25). (25
b) ) and the transmitting/receiving convergent optical element (3), and is sent to the optical space transmission line (8).
8), the received light transmitted through the transmission/reception converging optical element (3) and the light reflecting part (25b) of the mirror (25).
) (or the light transmitting section (25a)) and is made to enter the light receiving element (9) for receiving optical information.

F Function According to the present invention, the transmitted light emitted from the optical information transmitting light emitting element (5) is transmitted through the light transmitting portion (25) of the mirror (25).
5a) (or the light reflecting section (25b)) and the transmitting/receiving converging optical element (3), the optical space transmission line (8)
The received light transmitted through the optical space transmission line (8) is sent to the converging optical element (3) for transmitting and receiving and the mirror (3).
25) of the light reflecting part (25b) (or light transmitting part (25a)
) and are made to enter the light-receiving element (9) for receiving optical information.

G. Embodiments Below, embodiments of the present invention will be described with reference to the drawings.

G. First Embodiment The first embodiment of the present invention will be described below with reference to FIG. 1, and parts corresponding to those in FIG. Omit duplicate explanations.

Further, illustration and description of the lens barrel in which the optical system is housed will be omitted. (25) is a mirror for dividing transmitting and receiving light, and is a light transmitting part provided at the center of the parallel flat glass, that is, a through hole (25).
a) and the light reflecting part around it, that is, the reflecting surface formed by vapor deposition of aluminum on the parallel flat glass (
reflection plane) (25b). This through hole (25a
) is large enough to form an aerial image of the light emitting region of the light emitting element (laser diode) (5), that is, several tens of μm.
It is circular with a diameter of about 100 μm. and,
The through hole (25a) is located on the same optical axis of the transmitting/receiving lens (for example, 145 mm in diameter) (3) and the transmitting lens (6), and at a distance of 100 I from the transmitting/receiving lens (3).
It is located within the rake plane at a distance of about IIIll to 300III11, and its reflective surface (25b) has an angle of approximately 45° with respect to the same optical axis, and the transmitting/receiving lens (3) and the receiving lens ( 4) A mirror (25) is arranged with respect to the other optical elements so as to face the side. Further, the receiving lens (4) is arranged so that its optical axis is approximately perpendicular to the same optical axis of the transmitting/receiving lens (3) and the transmitting lens (6) at the through hole (25a) of the mirror (25). will be distributed.

In addition, in the above-mentioned embodiment, a through hole (
25a), this mirror (25) is formed with a reflective surface (25b) made of aluminum except for the center on a parallel flat glass, and the reflective surface of the parallel flat glass is The portion where (25b) is not formed can also be used as the optically transparent portion (25a).

Note that if sufficient received light L2 is incident on the light receiving element (9), the receiving lens (4) may be omitted.

Next, the operation of this optical space transmission device will be explained.

Transmission light (divergent light) L from the light emitting element (5) for transmitting optical information
l is converged by the transmitting lens (6) and focused at the through hole (25a) of the mirror (25),
Thereafter, it diverges toward the transmitting/receiving lens (3).

The divergent transmission light L1 is made into substantially parallel light by the transmitting/receiving lens (3), is emitted to the optical space transmission line (8), is transmitted, and is received by the optical space transmission device on the other side.

Further, the substantially parallel received light L2 transmitted from the optical space transmission device on the other side and transmitted through the optical space transmission line (8) is incident on the transmission/reception lens (3) and converged, and is converged by the mirror. The through hole (25a) in (25) focuses the beam to form a beam spot with a diameter of several 100 μm to several mm, and the polar part of the beam is directed toward the transmitting lens (6), but most of the beam spot is reflected by the reflective surface (25b) of the mirror (25).

The reflected divergent received light L2 is incident on the receiving lens (4) and converged, and is focused on the light receiving element (9).
incident. The received light L2 incident on the light receiving element (9) is converted into an electrical signal there.

G2 Second Embodiment A second embodiment of the present invention will be described below with reference to FIG. 2. Parts corresponding to those in FIG. The explanation will be omitted.

Further, illustration and description of the lens barrel in which the optical system is housed will be omitted. (25) ゛ is a mirror for splitting transmitting and receiving light, and is a light reflecting surface provided dot-like at the center of one surface of parallel flat glass, that is, a reflecting surface (reflecting plane) made of aluminum vapor deposition (25c) and a light transparent part (25d) around it. This reflective surface (25c) has a size sufficient to form an aerial image of the light emitting region of the light emitting element (laser diode) (5), that is, a substantially circular shape with a diameter of approximately several tens of micrometers to 100 micrometers. Then, the reflective surface (25C) is on the same optical axis of the husband's transmitting/receiving lens (3) and the receiving lens (4), and at a distance of 100 mm to 3 mm from the transmitting/receiving lens (3).
It is located within the rake plane at a distance of about 0.00 mm, forms an angle of approximately 45° with respect to the same optical axis, and faces the transmitting/receiving lens (3) and the transmitting lens (6). A mirror (25) is arranged with respect to other optical elements. Also, the transmitting lens (6) has its front axis aligned with the mirror (25).
At the reflective surface (25c) of the transmitter/receiver lens (3
) and the receiving lens (4) so as to be substantially orthogonal to the same optical axis.

Next, the operation of this optical space transmission device will be explained.

Transmission light (divergent light) L from the light emitting element (5) for transmitting optical information
L is converged by the transmitting lens (6),
The light is focused at the reflective surface (25c) of the mirror (25), and is reflected there and diverges toward the transmitting/receiving lens (3). The divergent transmission light L1 is made into approximately parallel light by the transmission/reception lens (3), and the optical space transmission line (
8), is transmitted, and is received by the optical space transmission device on the other side.

Further, the substantially parallel received light L2 transmitted from the optical space transmission device on the other side and transmitted through the optical space transmission line (8) is incident on the transmission/reception lens (3) and converged, and is converged by the mirror. It focuses near the reflective surface (25c) of the mirror (25), and a small portion of it is reflected by the reflective surface (25c) of the mirror (25) and heads toward the transmitting lens (6). Most of the light passes through the transparent portion (25d) of the mirror (25).

The divergent received light L2 that passed through this light transparent part (25d) is
The light enters the receiving lens (4) and is converged, and then enters the light receiving element (9) so as to be focused. The received light L2 incident on the light receiving element (9) is converted into an electrical signal there.

According to the optical space transmission device described with reference to FIGS. 1 and 2, the configuration is simple because the transmitting and receiving lens (3) can be used in common for the transmitted light L1 and the received light L2. Moreover, even if the lens (3) is used for both transmitting and receiving,
Optical loss associated with optical axis splitting is extremely small. Also, mirror (2
5), we split the transmitting and receiving light, so
The structure becomes simpler and the assembly work of the device becomes easier.

Furthermore, the mirror (25) allows the received light L2 to be efficiently incident on the light receiving element (9).

Furthermore, the mirror (25) allows the transmitted light L2 to be efficiently sent to the optical space transmission line (8). Therefore, it is possible to obtain an optical space transmission device in which the optical loss of the transmitted light L1 and the received light L2 due to optical axis splitting is small, and the assembly work of the device is easy.

G3 Third Embodiment In the first and second embodiments described above, after the transmission light L1 from the light emitting element (5) passes through the transmission lens (6),
This is a case where the transmission is made to reach the mirror (25) through space, but as in the third embodiment shown in FIG.
, the convergent transmitted light L1 emitted from the transmitting lens (6) is made to enter one end of the optical fiber (13) and guided therein, and the divergent transmitted light L1 emitted from the other end is passed through the other transmitting lens. (24), and the convergent transmission light L1 emitted from this may be made to enter the transmitting/receiving lens (3) through the through hole (25a) of the mirror (25) similar to that shown in FIG.

G4 Fourth Embodiment Also, as in the fourth embodiment shown in FIG. 4, the transmitting lens (24) in the third embodiment shown in FIG. 3 can be omitted. In this case, is the transmission optical fiber (13
) of the mirror (25) using adhesive or the like.

According to the optical space transmission device described with reference to FIGS. 3 and 4, the configuration is simple because the transmitting and receiving co-angle lens (3) can be used in common for the transmitted light L1 and the received light L2. Moreover, even if the lens (3) is used for both transmitting and receiving,
Optical loss associated with optical axis splitting is extremely small. In addition, although the transmitting optical fiber (13) is provided, there is no need to remove the protective film, and the transmitting and receiving light is divided by the transparent plate (11), which further simplifies the configuration and makes the device easier to use. Assembly work becomes easier. Furthermore, the mirror (25) allows the received light L2 to be efficiently incident on the light receiving element (9). Furthermore, the mirror (25) allows the transmitted light L2 to be efficiently sent to the optical space transmission line (8).

Therefore, it is possible to obtain an optical space transmission device in which the optical loss of the transmitted light L1 and the received light L2 due to optical axis splitting is small, the S/N ratio is small, and the assembly work of the device is easy.

In addition, instead of the transmitting/receiving common lens (convex lens) (3),
It is also possible to use a concave mirror for both transmission and reception.

H Effects of the Invention According to the present invention described above, it is possible to obtain an optical space transmission device that has a simple configuration, has little optical loss of transmitted light and received light due to optical axis division, and is easy to assemble. .

[Brief explanation of the drawing]

FIG. 1 is a layout diagram showing an optical space transmission device according to a first embodiment of the present invention, FIG. 2 is a layout diagram showing an optical space transmission device according to a second embodiment of the invention, and FIG. FIG. 4 is a layout diagram showing a part of the fourth embodiment; FIG. 5 is a layout diagram showing a part of the fourth embodiment;
The figure is a layout diagram showing a reference example of the optical space transmission device, FIG. 6 is a layout diagram showing the optical space transmission device of the first prior example of the present invention, and FIG. 8 is an end view of the bundle of the optical space transmission device of FIG. 6, and FIG. 9 is a layout diagram showing the optical space transmission device of the second prior example of the present invention. , FIG. 10 is a perspective view showing a support member of a spatial optical transmission device according to a third prior example of the present invention. (1) is a lens barrel, (3) is a transmitting and receiving lens, (4) is a receiving lens, (5) is a light emitting element for transmitting optical information, (6) is a transmitting lens, (8) is an optical space transmission line, (25) is a mirror, (25a) is a through hole, (25b) is a reflective surface, (25c)
(25d) is a reflective surface, and (25d) is a light transmitting part.

Claims (1)

[Scope of Claims] The light emitting device for transmitting optical information comprises: a light emitting element for transmitting optical information; a light receiving element for receiving optical information; a mirror having a light reflecting section and a light transmitting section; and a converging optical element for both transmission and reception; The transmitted light emitted from the element is sent out to an optical space transmission line through the light transmission part (or light reflection part) of the mirror and the transmission/reception common convergence optical element, and is transmitted through the optical space transmission line. The transmitted received light is made to pass sequentially through the transmitting/receiving converging optical element and the light reflecting part (or light transmitting part) of the mirror, and is made to enter the light receiving element for receiving optical information. Optical space transmission device.