JP3399809B2 - Light reflection device and optical space communication system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical space communication system for performing optical space communication between a plurality of terminal devices installed in an office or a home using optical signals such as infrared rays, and is installed on the ceiling of a room. Light reflection device.

[0002]

2. Description of the Related Art In order to perform optical space communication using optical signals such as infrared rays, an optical path for connecting an optical transmitter, which is a transmitter, and a photoelectric converter, which is an optical receiver, must be formed. . The optical signal used here is considered to be an ideal single-beam ray. The simplest is an optical path that connects the optical transmitter and the optical receiver with a straight line, but such an optical path is not practical because there are obstacles in ordinary optical space communication. For example, in order to perform optical space communication between terminals installed on a plurality of desks, other desks or shelves become obstacles, and it is not possible to use an optical path connecting the terminals with a straight line. In such a case, an optical path is used in which the optical signal emitted toward the ceiling reaches the optical receiver through some reflection there. Therefore, finding this optical path is indispensable for optical space communication using optical signals. Reflection on the ceiling is particularly important for achieving this, and the following first to fourth conventional examples have been proposed so far.

[0003](1) Method using diffuse reflection (below
Below, it is called the first conventional example. ) With this method, the optical transmission installed on the floor or desk
Diffuse reflection of light rays emitted from the belief installed on the entire ceiling
It is reflected by the plate and reaches the optical receiver. Incident on the diffuse reflector on the ceiling
By slightly changing the position or direction of the light beam,
The emitted light changes greatly, so it is easy to
You can discover the optical path to reach the receiver. Also, the optical transmitter and
Even if there are multiple optical receivers and optical receivers, optical space communication can be performed simultaneously.
It can be performed.

(2) Method of using movable plane mirror
Below, it is called the second conventional example. In this method, a light beam emitted from an optical transmitter installed on the floor or on a desk is reflected by a small movable plane mirror suspended from the ceiling and reaches an optical receiver. Attenuation of light intensity can be prevented by using a mirror having high reflectance.
The method of searching the optical path connecting the transmitter and the receiver is to change the direction of the light beam reflected by the mirror and directed to the floor surface by changing the inclination of the plane mirror. Since there is no attenuation of intensity, reliable optical space communication is realized.

(3) Utilizing a plane mirror that covers the entire ceiling
In this method, a light beam emitted from an optical transmitter installed on the floor or on a desk is reflected by a large plane mirror covering the entire ceiling and reaches the optical receiver. . By using a mirror with high reflectance, attenuation of light intensity can be prevented and reliable optical space communication can be performed. Further, even when there are a plurality of optical transmitters and optical receivers, it is possible to perform optical space communication at the same time. The method of searching the optical path connecting the transmitter and the receiver is to change the emission direction of the light beam from the optical transmitter and control so as to reach the optical receiver.

[0006](4) Method using a hemispherical mirror (below
Below, it is called the fourth conventional example. ) With this method, the optical transmission installed on the floor or desk
A hemispherical mirror mounted on the ceiling where the light rays emitted from the
It is reflected by Ra and reaches the receiver. Use a mirror with high reflectance
Light beam intensity can be prevented by
Inter-communication is possible. In addition, there are multiple optical transmitters and optical receivers.
Even if they are present, they can simultaneously perform optical space communication
It The method of searching the optical path connecting the transmitter and receiver is
Controls to change the emitting direction of the light beam to reach the optical receiver
That is.

[0007]

The above four conventional examples have the following problems, respectively.

(1) First Conventional Example Since the light intensity is weakened by the absorption of light by the diffuse reflection plate, it is necessary to increase the transmission light power so that it can be detected by the optical receiver.

(2) Second Conventional Example It takes a long time to search the optical path. Also, optical space communication cannot be performed simultaneously by a plurality of transceivers.

(3) Due to the reflection characteristics of the third conventional plane mirror, even if the emission direction of the optical transmitter is changed, the arrival point on the floor surface of the light beam reflected by the plane mirror does not change significantly. It takes a long time to search.
In addition, searching by changing the emission direction of the optical transmitter two-dimensionally becomes a factor of increasing the search time of the optical path. In addition, a flat mirror having a high reflectance that covers the entire ceiling is expensive to manufacture and install, and safety is not ensured.

(4) Fourth Conventional Example Since the change in the emission direction of the optical transmitter needs to be two-dimensional, a longer optical path search time is required accordingly.

The object of the present invention is to solve the above problems and to search the optical path from the optical transmitter to the optical receiver in a shorter time than in the conventional example, and moreover, the structure is simple and the cost is low. Therefore, it is an object of the present invention to provide a light reflection device capable of simultaneously performing light space communication between a plurality of transceivers, and an optical space communication system using the light reflection device.

[0013]

A light reflecting device according to a first aspect of the present invention is a light reflecting device for reflecting an optical signal transmitted from an optical transmitter and transmitting the reflected optical signal to an optical receiver. ,
The centers of four hollow spherical mirrors, each having the same diameter as each side of the regular tetrahedron and having a mirror surface on the outer surface, are respectively located at the vertices of the virtual regular tetrahedron, and the four After mounting the above four spherical mirrors so that each two spherical mirrors of the above spherical mirrors come into contact with each other at one point, three spherical mirrors are set from the above four spherical mirrors as one set. First of all 4 sets of spherical mirrors when selected
And a second, a third, and a fourth set of three spherical mirrors, cut on a first plane passing through the centers of the three spherical mirrors of the first set, and on the first plane. A first plane mirror fitted into a plane formed by three curves formed by the first set of three spherical mirrors, and having at least a mirror surface facing the inside of the regular tetrahedron; and the second set. Is cut at a second plane passing through the respective centers of the three spherical mirrors of 3 to form the second set of three spherical mirrors on the second plane.
A second plane mirror fitted in a plane formed by two curves and having at least a mirror surface facing the inside of the regular tetrahedron, and a third plane mirror passing through respective centers of the three spherical mirrors of the third set. A plane having at least a mirror surface cut along a plane and fitted into a plane formed by three curves formed by the third spherical mirrors of the third set on the third plane and facing the inside of the regular tetrahedron. No. 3 plane mirror and a fourth plane passing through the centers of the three spherical mirrors of the fourth set are cut to form a fourth set of three spherical mirrors on the fourth plane. An opening having a plane formed by three curved lines,
First, second and third parts formed by cutting the four spherical mirrors along the first, second, third and fourth planes, respectively.
And a fourth spherical mirror, and when an optical signal is incident through the opening, the optical signal includes the first, second, third and fourth spherical mirrors and the first and second spherical mirrors. And at least one of the third plane mirrors is reflected and emitted through the opening.

According to a second aspect of the present invention, there is provided the optical space communication system according to the first aspect, and at least one light emitting device that emits an optical signal so as to pass through the light reflecting device and the opening of the light reflecting device. Optical transmitter, and the optical signal from the optical transmitter passes through the opening of the light reflecting device, and then the first, second, third and fourth spherical mirrors of the light reflecting device and the first And at least one optical receiver for receiving an optical signal reflected by at least one of the second and third plane mirrors and emitted through the opening. .

[0015]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing an external appearance of the light reflecting device 10 according to one embodiment of the present invention, as seen from an oblique front of a plane mirror AFD, and FIG. 2 is the light reflecting device 10 described above. FIG. 4 is a plan view showing the appearance of the light reflecting device 10 as seen from above the spherical mirror DEF, FIG. 3 is a bottom view of the light reflecting device 10 seen toward the opening ABC, and FIG. The light reflection device 10 has the spherical mirror A
FIG. 5 is a side view when viewed toward DC, and FIG. 5 is a side view when the light reflection device 10 is viewed toward the plane mirror AFD thereof.

As shown in FIG. 26, for example, the light reflecting device 10 of the present embodiment is a device which is provided on the ceiling of a room 90 for performing optical space communication with two optical space communication terminal devices. That is, the light reflecting device 10 is a light reflecting device for reflecting the optical signal transmitted from the optical transmitter and transmitting the optical signal to the optical receiver. As shown in FIGS. 6 and 7, a virtual tetrahedron is used. Four hollow spherical mirrors S each having the same diameter as each side of the regular tetrahedron RT1 at each vertex T1, T2, T3, T4 of RT1 and having a mirror surface on at least the outer surface.
The centers of M1, SM2, SM3 and SM4 are respectively located and the four spherical mirrors SM1, SM2, SM3 and
The four spherical mirrors SM1, SM2, SM so that each two spherical mirrors of SM4 contact each other at one point.
After mounting 3, SM4, the above four spherical mirrors SM
When four spherical mirrors are selected from 1, SM2, SM3, and SM4 as one set, four spherical mirrors are set as three spherical mirrors of the first, second, third, and fourth sets. .

Here, as shown in FIG. 8 (a), the light reflecting device 10 includes three spherical mirrors SM of the first set.
1, SM2, SM4 are cut along a first plane passing through the respective centers to form three curves AD, DF, FA formed by the first set of three spherical mirrors on the first plane. A first plane mirror ADF (hereinafter referred to as
ADF is a plane mirror formed by curves AD, DF, FA
And so on. Also, the same reference numerals are given to the spherical mirror and the opening. ) And (b) cutting at a second plane passing through the centers of the three spherical mirrors SM2, SM3, SM4 of the second set, and the third set of three mirrors on the second plane. A second plane mirror BEF fitted into a plane formed by the three curves formed by the spherical mirrors SM2, SM3, and SM4, and having at least a mirror surface facing the inside of the regular tetrahedron RT1, and (c) the third plane mirror BEF. The three spherical mirrors SM1, SM3, SM4 of the third set are cut at a third plane passing through the respective centers, and the third spherical mirrors SM1, SM3, SM4 of the third set on the third plane are Forming 3
Fitted in the plane formed by two curves, the above tetrahedron R
A third plane mirror CDE having at least a mirror surface facing the inside of T1, and (d) cutting at a fourth plane passing through the centers of the three spherical mirrors SM1, SM2, SM3 of the fourth set. An opening ABC having a plane formed by three curves formed by the fourth group of three spherical mirrors SM1, SM2, SM3 on the fourth plane, and (e) the above-mentioned 4
First, second, third and fourth spherical mirrors formed by being cut along the first, second, third and fourth planes, respectively.
Spherical mirrors ABF, ADC, BCE, and DFE. Then, when an optical signal is incident through the opening ABC, the optical signal includes the first, second, third, and fourth spherical mirrors ABF, ADC, BCE, DFE, and the first spherical mirror.
And at least one of the second and third plane mirrors AFD, BEF, and CDE is reflected to reflect the opening AB.
It is characterized in that the light is emitted via C.

In the optical space communication system of this embodiment, for example, as shown in FIG. 26, at least one optical signal is emitted so as to pass through the opening ABC of the light reflecting device 10.
After the optical space communication terminal device (hereinafter referred to as a terminal device) 50-1 which is an optical transmitter and an optical signal from the terminal device 50-1 have passed through the opening ABC of the light reflecting device 10, At least one of the first, second, third and fourth spherical mirrors ABF, ADC, BCE, DFE and the first, second and third flat mirrors AFD, BEF, CDE of the light reflecting device 10 The above-mentioned opening ABC by reflecting one mirror
And a terminal device 50-11 which is at least one optical receiver for receiving an optical signal emitted via the terminal.

In order to be able to find the optical receiver by a short-time search in the optical transmitter, a minute change in the light beam emitted from the optical transmitter causes a large change due to reflection on the ceiling side, and a small change in the floor surface. It is necessary to greatly change the arrival point of the light beam. Moreover, it is necessary not to have a disordered structure so that the light intensity is not attenuated. The present inventor has invented the light reflecting device 10 shown in FIG. 1 as having such characteristics. The light reflecting device 10 of the embodiment according to the present invention uses four spherical mirrors and three plane mirrors.

FIGS. 6, 7 and 8 are perspective views showing the manufacturing process of the light reflecting device 10 of this embodiment. First, FIG.
4 spherical mirrors (the radius of the sphere is 1 and the centers of the spherical mirrors are O1, O2, O3, O4.) SM1, SM2, SM3, SM4 are prepared, and a virtual tetrahedron is prepared. (The length of one side is 2, and each vertex is T
1, T2, T3, T4. ) Consider RT1. The four spherical mirrors SM1-SM4 are arranged so that the centers O1, O2, O3, O4 of these spherical mirrors coincide with the centers T1, T2, T3, T4 of the regular tetrahedron RT1, respectively, as shown in FIG. Is. Next, the combination of the spherical mirrors SM1-SM4 is cut along a plane including the surface T1T2T4 of the regular tetrahedron RT1. This operation results in the one shown in FIG. Combination of spherical mirrors SM1-SM4 and surface T1T2T
Partial AF of surface T1T2T4 surrounded by intersection line AFD with 4
D is a plane mirror AFD having the same shape as this (this plane mirror has a mirror surface facing the inside of the regular tetrahedron RT1).
Close with. The same operation is performed for surface T3T1T4 and surface T2T3T.
Repeat for 4. Further, the combination of the spherical mirrors is cut at the plane including the surface T1T2T3, but the plane mirror does not close. That is, the portion surrounded by the curve ABC in FIG. 4 is an incident portion, and light can enter from this portion, which is referred to as an opening portion ABC.

Next, the manufacturing process of the light reflecting device 10 will be described in detail. As shown in FIGS. 6 and 7, a virtual tetrahedron RT
At each vertex T1, T2, T3, T4 of 1, the above-mentioned regular tetrahedron R
Four hollow spherical mirrors SM1 and S each having the same diameter as each side of T1 and at least a mirror surface on the outer surface.
The centers of M2, SM3 and SM4 are respectively located and 4
The four spherical mirrors SM1, SM2, SM3, SM4 are mounted so that two spherical mirrors SM1, SM2, SM3, SM4 are in contact with each other at one point. Here, the spherical mirror SM1 is a spherical mirror SM2.
With the contact point A, with the contact point C with the spherical mirror SM3, and with the contact point D with the spherical mirror SM4. The spherical mirror SM2 is in contact with the spherical mirror SM3 at a contact point B, and is in contact with the spherical mirror SM4 at a contact point F. The spherical mirror SM3 is a spherical mirror SM4
And contact point E. The above four spherical mirrors SM1 and SM
When three spherical mirrors are selected from 2, SM3 and SM4 as one set, the four spherical mirrors are the first, second, third and fourth spherical mirrors.

Next, as shown in FIG. 8, the three spherical mirrors SM1, SM2, SM4 of the first set are cut along a first plane passing through the respective centers, and the first plane on the first plane is cut. 1
Curves AD, D formed by the three spherical mirrors of the set
A first plane mirror A having at least a mirror surface facing the inside of the regular tetrahedron RT1 on a plane formed by F and FA.
Insert the DF. Then, the second set of three spherical mirrors SM2, SM3, SM4 is cut at a second plane passing through the respective centers, and the second set of three spherical mirrors SM2 on the second plane is cut. , SM3, SM4, a second plane mirror BEF having at least a mirror surface facing the inside of the regular tetrahedron RT1 is fitted into the plane formed by the three curves. Then, the third set of three spherical mirrors SM
3, SM3, SM4 cut along a third plane passing through the respective centers to form three curves formed by the third set of three spherical mirrors SM1, SM3, SM4 on the third plane. A third plane mirror CDE having at least a mirror surface facing the inside of the regular tetrahedron RT1 is fitted into the plane.
Then, the fourth set of three spherical mirrors SM1, SM
2, SM3 is cut at a fourth plane passing through the respective centers, and a fourth set of three spherical mirrors SM1, on the fourth plane.
The plane formed by the three curves formed by SM2 and SM3 is formed as the opening ABC. Further, the four spherical mirrors formed by cutting and remaining the four spherical mirrors on the first, second, third, and fourth planes are spherical mirrors ABF, ADC, BCE, and DFE. .

Here, the spherical mirror ABF is a spherical mirror S.
Part of M2, spherical mirror ADC is spherical mirror SM
1 is a part of the spherical mirror BCE is a spherical mirror SM3.
The spherical mirror DFE is a part of the spherical mirror SM4.

2 to 5, in order from above, just below, just beside,
The external appearance of the light reflection device 10 viewed from the side of another angle is shown. As will be described later in detail, the light reflection device 10 according to the present embodiment.
A light beam that has entered from the outside through the opening ABC undergoes complex multiple reflection inside the device, and then is emitted to the outside again through the opening ABC. Due to this multiple reflection, even a slight change in the incident light beam causes a very large change in the output light beam. In particular, the following are important. As shown in FIG. 19, the light reflecting device 10 according to the present embodiment has an opening AB on the ceiling.
It is installed so that C is at the bottom, and the light rays from the terminal device 50-1, which is an optical transmitter on the floor or a desk, are constrained to change within a certain plane, that is, the emission direction and position of the light rays are changed one-dimensionally It means to let. At this time, the arrival point on the floor surface of the light beam that reaches the floor surface through the light reflecting device 10 has a two-dimensional spread. Therefore, when the optical path connecting the transmitter and the receiver is searched, the outgoing light beam of the optical transmitter may be one-dimensionally swayed, so that the desired optical path can be found in a short time. Here, instead of fixing the position of the incident ray and swinging the direction one-dimensionally, even when the direction of the incident ray is fixed and the position is changed in parallel, the outgoing ray spreads two-dimensionally. Have.

[0026]

EXAMPLES FIGS. 9 to 13 show examples in which the position of a light beam incident on the light reflecting device 10 of the present embodiment is fixed and the direction is changed one-dimensionally, and FIGS. Is
This is an example in which the direction of the light beam incident on the light reflection device 10 of the present embodiment is fixed and the position is changed one-dimensionally. Hereinafter, each embodiment will be described.

FIG. 9 is a view corresponding to FIG.
It is a perspective view which shows the reflected light in the reflection case of FIG. The light ray that is incident with a slight inclination with respect to the direction directly above is first reflected at the point R901 of the spherical mirror DFE, and the opening A on the bottom surface
The point S1 on the floor is reached through the BC.

FIG. 10 is a view corresponding to FIG. 1, and is a perspective view showing reflected light rays in the second reflection case.
Light rays that are incident at a slightly greater inclination than in the case of FIG.
First, it reflects at the point R1001 of the spherical mirror DFE, then reflects at the point R1002 of the spherical mirror ABF, and reaches the point S2 on the floor through the opening ABC on the bottom.

FIG. 11 is a view corresponding to FIG. 1, and is a perspective view showing a reflected light ray in the third reflecting case.
The light ray which is incident at a slightly larger inclination than in the case of FIG. 10 is first reflected at the point R1101 of the spherical mirror DFE, then at the point R1102 of the spherical mirror ABF, and then at the point R1103 of the spherical mirror BCE. Then, it reaches the point S3 on the floor through the opening ABC on the bottom.

FIG. 12 corresponds to FIG. 1 and is a perspective view showing a reflected light ray in the fourth reflecting case.
The light ray that is incident at an angle slightly larger than that in the case of FIG. 11 reaches a point S4 on the floor surface through complicated reflection. The order of the mirrors by which the incident light ray is reflected before passing through the opening ABC on the bottom surface is as follows. Spherical mirror DFE, spherical mirror ABF, spherical mirror BCE, plane mirror AFD,
Spherical mirror BCE, spherical mirror ADC, spherical mirror BC
E, spherical mirror ABF, flat mirror CDE, spherical mirror ABF, spherical mirror DFE, spherical mirror ADC, spherical mirror ABF, flat mirror BEF, spherical mirror ADC, spherical mirror BCE.

FIG. 13 is a view corresponding to FIG. 1 and is a perspective view showing a reflected light ray in the fifth reflection case.
When the inclination of the incident light beam is changed little by little, the arrival point on the floor surface changes greatly due to the change in the reflection method inside the device. Here, the change of the reflection method is as follows. The light rays reaching P1, P2, and P3 are reflected by the spherical mirror DFE and reach the floor surface through the opening ABC on the bottom surface. The light rays that reach Q1, Q2, and Q3 are first reflected by the spherical mirror DFE, then by the spherical mirror ABF, and then reach the floor through the opening ABC on the bottom surface. R
The light rays reaching 1, R2 are first reflected by the spherical mirror DFE, then by the spherical mirror ABF, then by the spherical mirror BCE, and then reach the floor through the opening ABC on the bottom surface. Thus, it is understood that the arrival point on the floor has a two-dimensional spread only by changing the angle of the incident light beam one-dimensionally.

FIG. 14 is a view corresponding to FIG. 1, and is a perspective view showing a reflected light ray in the sixth reflecting case.
A light ray incident from a position slightly deviated from the center of the opening ABC is first reflected by the point 1401 of the spherical mirror DFE,
Reach point S5 on the floor through the opening ABC on the bottom

FIG. 15 is a view corresponding to FIG. 1, and is a perspective view showing reflected light rays in the seventh reflection case.
Light rays that are slightly deviated from the case of FIG.
First, it reflects at the point R1501 of the spherical mirror DFE, then reflects at the point 1502 of the spherical mirror ABF, and reaches the point S6 on the floor through the opening ABC on the bottom.

FIG. 16 is a view corresponding to FIG. 1, and is a perspective view showing a reflected ray in the eighth reflecting case.
The light ray which is slightly deviated from the case of FIG. 15 is first reflected by the point R1601 of the spherical mirror DFE,
Next, it reflects at a point R1602 on the spherical mirror ABF, then at a point R1603 on the spherical mirror BCE, and reaches a point S7 on the floor through the opening ABC on the bottom.

FIG. 17 is a view corresponding to FIG. 1, and is a perspective view showing a reflected light ray in the ninth reflecting case.
The light beam which is slightly deviated from that in the case of FIG. 16 reaches a point S8 on the floor surface through complicated reflection. The order of the mirrors by which the incident light ray is reflected before passing through the opening ABC on the bottom surface is as follows. Spherical mirror DFE, spherical mirror ABF, spherical mirror BCE, spherical mirror ADC, spherical mirror ABF, spherical mirror ADC, spherical mirror AB
F, spherical mirror DFE, spherical mirror ADC, spherical mirror DFE, spherical mirror ADC, flat mirror BEF, spherical mirror ABF, spherical mirror ADC, flat mirror BEF, spherical mirror DFE, spherical mirror ADC, spherical mirror DF
E, plane mirror BEF, spherical mirror ABF, plane mirror AFD, spherical mirror ADC, spherical mirror BCE.

FIG. 18 is a perspective view corresponding to FIG. 1 and showing a reflected light ray in the tenth reflecting case. When the position of the incident light beam is changed little by little, the arrival point on the floor surface changes greatly due to the change in the reflection method inside the device. Here, the change of the reflection method is as follows. The light rays reaching P4, P5, and P6 are reflected by the spherical mirror DFE and reach the floor surface through the opening ABC on the bottom surface. The light rays reaching Q4 and Q5 are first reflected by the spherical mirror DFE, then by the spherical mirror ABF, and then reach the floor through the opening ABC on the bottom surface. R
The rays reaching 3 and R4 are first reflected by the spherical mirror DFE, then by the spherical mirror ABF, then by the spherical mirror BCE, and then reach the floor through the opening ABC on the bottom surface. Thus, it is understood that the arrival point on the floor has a two-dimensional spread only by changing the angle of the incident light beam one-dimensionally.

FIG. 19 is a perspective view showing the arrangement of the light reflecting device 10 in the room 90 used in the optical space communication system of the example of this embodiment. This is the arrangement used in the simulation of this embodiment, and each number represents the normalized length. As is clear from FIG. 19, 50
The central part of the room 90 of x50x8 (coordinates (25, 25))
The light reflecting device 10 is hung on the ceiling of the upper surface of the above so that the opening ABC faces the floor surface (lower surface) of the room. In the simulation, reflection loss and propagation loss are assumed to be zero.

FIG. 20 is a plan view showing a position where the optical signal can be received on the bottom surface of the room 90 when the optical signal is transmitted from the transmitting side terminal device in the optical space communication system of the first example of the present embodiment. It is a figure. 20 is a line segment connecting the midpoint of A and BC of the opening ABC of the bottom surface of the light reflecting device 10 from the position of the light source fixed to the point (3, 4) on the xy plane of the floor in FIG. Light reflection device 1 to move on
It is a plot of the position of the optical receiver reached by the outgoing light beam when the direction of the incoming light beam to 0 is changed, and the change in direction is 0.98 ° in angle. It can be seen that the emitted light beam spreads over the entire floor surface and can reach almost all points.

FIG. 21 is a plan view showing a position where the optical signal can be received on the bottom surface of the room 90 when the optical signal is transmitted from the transmitting side terminal device in the optical space communication system of the second example of the present embodiment. It is a figure. In FIG. 21, the position of the light source is fixed to the point (3, 12) on the xy plane of the floor in FIG.
Is a plot of the position of the optical receiver that the outgoing light beam reaches when the direction of the incident light beam to the light reflecting device 10 is changed so as to move on the line segment connecting the midpoints of A and BC of The change in angle is 1.34 °. It can be seen that the emitted light beam spreads over the entire floor surface and can reach almost all points.

FIG. 22 is a plan view showing a position where the optical signal can be received on the bottom surface of the room 90 when the optical signal is transmitted from the transmitting side terminal device in the optical space communication system of the third example of the present embodiment. It is a figure. In FIG. 22, the position of the light source is fixed to a point (3, 20) on the xy plane of the floor surface in FIG.
Is a plot of the position of the optical receiver that the outgoing light beam reaches when the direction of the incident light beam to the light reflecting device 10 is changed so as to move on the line segment connecting the midpoints of A and BC of The change in angle is 1.68 °. It can be seen that the emitted light beam spreads over the entire floor surface and can reach almost all points.

FIG. 23 is a plan view showing a position where the optical signal can be received on the bottom surface of the room 90 when the optical signal is transmitted from the transmitting side terminal device in the optical space communication system of the fourth example of the present embodiment. It is a figure. FIG. 23 shows that the emission direction of light rays is fixed from a point (3, 4) on the xy plane of the floor surface in FIG.
It is a plot of the position of the optical receiver that the outgoing light beam reaches when the position of the incident light beam to the light reflecting device 10 is changed so as to move on the line segment connecting the middle points of A and BC of BC, The change in position is 0.73 in distance. It can be seen that the emitted light beam spreads over the entire floor surface and can reach almost all points.

FIG. 24 is a plan view showing a position where the optical signal can be received on the bottom surface of the room 90 when the optical signal is transmitted from the transmitting side terminal device in the optical space communication system of the fifth example of the present embodiment. It is a figure. 24 is a line connecting the midpoints A and BC of the opening ABC of the bottom surface of the light reflecting device 10 from the point (3, 12) on the xy plane of the floor in FIG. This is a plot of the position of the optical receiver reached by the outgoing light beam when the position of the incoming light beam to the light reflecting device 10 is changed so as to move upwards. The change in position is 0.73 in terms of distance. is there. It can be seen that the emitted light beam spreads over the entire floor surface and can reach almost all points.

FIG. 25 is a plane view showing the position where the optical signal can be received on the bottom surface of the room 90 when the optical signal is transmitted from the transmitting side terminal device in the optical space communication system of the sixth example of this embodiment. It is a figure. 25 is a line connecting the midpoints A and BC of the opening ABC of the bottom surface of the light reflecting device 10 from the fixed point (3, 20) on the xy plane of the floor surface in FIG. It is a plot of the position of the optical receiver reached by the emitted light beam when the position of the incident light beam on the light reflection device 10 is changed so as to move upward. The change in position is 0.73 in distance. It can be seen that the emitted light beam spreads over the entire floor surface and can reach almost all points.

Next, an embodiment of the optical space communication system will be described. FIG. 26 shows one receiving side terminal device 50-1 from one transmitting side terminal device 50-1 via the light reflecting device 10 in the optical space communication system of the first embodiment.
2 is a perspective view showing a state when an optical signal is transmitted toward 1. FIG. The reference numerals of the terminal devices are collectively referred to as 50.

FIG. 29 is a block diagram showing the configuration of an optical space communication terminal device 50 for the optical space communication system of this embodiment. In FIG. 29, transmission data to be transmitted by optical space communication is input to a personal computer 51 using a keyboard 52, for example, and a CRT display 53 is displayed.
And is input to the laser diode 55 via the interface 54 that performs signal conversion and the like. The laser diode 55 intensity-modulates the generated optical signal according to the input transmission data, and the modulated optical signal is collimated by the collimator lens 59 via the beam splitter 58.
By outputting to the light radiator 59 provided with a, the beam of the optical signal intensity-modulated by the transmission data is transmitted to the light reflecting device 10.
Sent to. On the other hand, the optical signal reflected by the light reflecting device 10 is received by the light emitter 59, then branched by the beam splitter 58 and input to the photoelectric converter 56 which is a photodetector. The photoelectric converter 56 converts an input optical signal into reception data of an electric signal, and receives the personal computer 51 via an interface 57 that performs signal conversion and the like.
Output to. The personal computer 51 displays the input received data on the CRT display 53.

Further, FIG. 27 shows that in the optical space communication system of the second embodiment, one transmitting side terminal device 50-1 and three receiving side terminal devices 50- via the light reflecting device 10.
It is a perspective view which shows the state at the time of transmitting an optical signal toward 11,50-12,50-13. Furthermore, FIG.
Are three receiving-side terminal devices 50-1 from the three transmitting-side terminal devices 50-1, 50-2, 50-3 via the light reflecting device 10 in the optical space communication system of the third embodiment.
It is a perspective view which shows the state at the time of transmitting an optical signal toward 1,50-12,50-13.

When the light rays incident on the light reflecting device 10 of this embodiment are constrained within a certain plane to be changed, the points on the floor where the light rays emitted from the light reflecting device 10 reach have a two-dimensional spread. This will be described below with reference to FIGS. 30 and 31. FIG. 30 shows the light reflecting device 10 of the present embodiment.
31 is a perspective view of a plane mirror A _{j + 1} used to show the reflection process of FIG. 31, and FIG. 31 is a perspective view of a spherical mirror S _{j + 1} used to show the reflection process of the light reflecting device 10 of the present embodiment. is there.

First, consider the reflection of a light beam by the plane mirror A _{j + 1} . The emission point of the ray l _j and the direction vector there are x _j and u _j , respectively. Further, the direction points of the reflection point of this light ray l _{j on} the plane mirror A _{j + 1} and the reflected light ray l _{j + 1} there are respectively defined as x _{j + 1} and u _{j + 1} . The unit normal vector of the plane including the plane mirror A _{j + 1} is nA _{j + 1} .
The light ray l _j and the plane mirror A _{j + 1} are respectively expressed by the following equations.

## EQU1 ## x = x _j + tu _j

## EQU00002 ## n _{Aj + 1.x +} d = 0 where t is a parameter and d is a plane mirror A _{j + 1.}
Is the distance from the origin.

Therefore, substituting x _{j + 1} for x

[Mathematical formula-see original _document ] x _{j + 1} = x _j − {(n _{Aj + 1} · x _j + d) · u _j } /
Obtain (n _{Aj + 1} · u _j ). Also,

## EQU4 ## From u _{j + 1} −u _j = | u _{j + 1} −u _j | n _{Aj + 1}

## EQU5 ## u _{j + 1} = u _j -2 (u _j · n _{Aj + 1} ) n _{Aj + 1} .

Next, from the equations 3 and 5, the reflected ray l _{j + 1}
Using the parameter t,

[6] _{x = x j - {(n} Aj + 1 · x j + d) · u j} /
(N _{Aj + 1} · u _j ) + t {u _j −2 (u _j · n _{Aj + 1} )
n _{Aj + 1} }. Therefore, the plane mirror A is placed above the xy plane.
When there is _{j + 1} , when the light ray emitted from the point (x, y, 0) on the xy plane is reflected by the plane mirror A _{j + 1} and reaches the point (x ′, y ′, 0) on the xy plane,

X '= x + (ax + by + d) (cu-wa)
/ (W-2hc)

Y ′ = y + (ax + by + d) (cv-wb)
/ (W-2hc). here

## EQU9 ## h = au + by + cw And

The above equations 7 and 8 can be rewritten as the following equation.

X ′ = [1+ (acu−a ² w) / (w−2)
hc)] x + (bcu-abw) y / (w-2hc) +
d (cu-wa) / (w-2hc)

Y '= (acv-abw) x / (w-2h)
c) + [1+ (acu-a ² w) / (w-2hc)] y +
d (cv-wb) / (w-2hc)

Further, from the equations (10) and (11), when the emission point (x, y, 0) of the optical transmitter moves on a straight line, the point (x ',
It can be seen that y ', 0) also moves on a straight line. In other words, when the firing direction is fixed and the firing position in the xy plane is translated,
The arrival point on the xy plane of the reflected ray from the plane mirror A _{j + 1} draws a straight line.

Further, the point (x, y, 0) is fixed, and the direction vector of the emitted ray is represented by "u = se + x _A , v = sf + y _A ,
When taken on a straight line passing through the points (xA, yA, zA) such as “w = sg + z _A ”, Equations 7 and 8 can be rewritten as the following equations.

X '= x + (ax + by + d) (sce-sf
_{a + cx A -az A) /} (sg + z A -2hc)

Y '= y + (ax + by + d) (scf-sg
_{b + cy A -bz A) /} (sg + z A -2hc)

Here, when the vector (e, f, g) is taken on the plane mirror A _{j + 1} , "h = ax _A + by _A + c"
z _A ”and becomes a constant. Therefore, when s is changed, that is, when the emission position of the xy plane is fixed and the emission direction is changed within a certain plane, the arrival point of the reflected ray from the plane mirror A _{j + 1 on} the xy plane draws a straight line.

Next, consider reflection by the spherical mirror S _{j + 1} . The unit vectors of the emission point of the ray l _j and the direction there are x _j and u _j , respectively. Also, the center x _{Cj + 1} and the radius r
_{Cj + 1} of the spherical mirror S _{j + 1,} respectively x _{j + 1} reflected ray l _{j + 1} in the direction of the unit vector in the reflection point and there in, u j _{+ 1}
The ray l _j and the spherical mirror S _{j + 1} are expressed by the following equations. In this specification, since subscripts cannot be subscripted, they are indicated as x _{Cj + 1} and so on.

X = x _j + tu _j

## _EQU15 ## | x−x _{Cj + 1} | = r _{Cj + 1} where t is a parameter.

Solve these

X _{j + 1} = x _j + {(x _{Cj + 1} −x _j ) u _j −
_{[{(X j -x Cj +} 1) u j} 2 + r 2 Cj + 1 - (x j -
x _{Cj + 1} ) ² ] ^1/2 } u _j

[Mathematical formula-see original document] u _{j + 1} = u _j -2 / (r _{Cj + 1} ) · (u _j · [x _j
+ {(X _{cj + 1} −x _j ) · u _j − [{(x _j −x _{Cj + 1} ) ·
^{_{u j} 2 + r 2 Cj}} + 1 - (x j -x Cj + 1) 2] 1/2} u j) -x
_{Cj + 1] × [x j} + {(x Cj + 1 -x j) · u j - [{(x j -
x _{Cj + 1} ) · u _j } ² + r ² _{Cj + 1} − (x _j −x _{Cj + 1} ) ² ] ^1/2 }
u _j -x _{Cj + 1} ] is obtained.

Therefore, the spherical mirror S is placed above the xy plane.
When there is _{j + 1} , when the light ray emitted from the point (x, y, 0) on the xy plane is reflected by the plane mirror A _{j + 1} and reaches the point (x ′, y ′, 0) on the xy plane,

X ′ = {− xu−yv + z _C w − [(xu +
^{_{yv-z C w 2) +}} r 2 C -x 2 -y 2 -z 2 C] 1/2} u + s *
^{{U + 2 / (r 2} C) [(xu 2 + yv 2 -z C w 2) + r 2 C
_{^{-X 2 -y 2 -z 2 C]}} x + r 2 C -x 2 -y 2 -z 2 C} u

Y ′ = {− xu−yv + z _C w − [(xu +
^{_{yv-z C w 2) +}} r 2 C -x 2 -y 2 -z 2 C] 1/2} v + s *
^{{U + 2 / (r 2} C) [(xu 2 + yv 2 -z C w 2) + r 2 C
The _{^{-x 2 -y 2 -z 2 C]}} y + r 2 C -x 2 -y 2 -z 2 C} v.

Here,

S * = [α + (β + γ) ^1/2 w] / [w-2 /
(R ² _C ) (β + γ) ^1/2 (z _C + α)] − 2 / r ² _C (β +
γ) w

Α = xuw + yvw-zw ²

Β = xu ² + yv ² −z _C w ²

Γ = r ² _C −x ² −y ² −z ² _C

From the above equations 18 to 23, the dependence of x ', y'on x, y, u, v, w is non-linear. Therefore, x
When the spherical mirror S _{j + 1} is above the y plane, when the emitting direction of the light beam emitted from the point (x, y, 0) on the xy plane is fixed and the position is moved in parallel, or the emitting position is fixed and the light is emitted. It can be seen that the reaching point (x ′, y ′, 0) in the xy plane draws a curve when the direction changes in a certain plane.

As shown in FIG. 1, the light reflecting device 10 of the present embodiment is arranged so that DEF is on the upper side, and from the xy plane below the opening ABC, the position of the outgoing light beam is fixed and the direction is a plane. The plane mirror A _{j + 1} and the spherical mirror described above with respect to the behavior of the light beam that is incident on the inside of the device through the opening ABC on the bottom surface by changing the position inside the device or by changing the position and moving the position in parallel. Consider using the relation of reflection by S _{j + 1} .

Here, there are the following seven possibilities for the first reflecting mirror of the light beam entering the inside of the apparatus. (1) spherical mirror DFE, (2) spherical mirror ABF,
(3) Spherical mirror ADC, (4) Spherical mirror BCE,
(5) plane mirror AFD, (6) plane mirror CDE,
(7) Due to the symmetry of the plane mirror BEF and the light reflecting device 10, (2), (3) and (4) are equivalent, and similarly (5), (6) and (7) are equivalent. Therefore, it is sufficient to consider the above (1), (2), and (5).

(1) When reflected by the spherical mirror DFE,
There are the following seven possible behaviors of reflected light rays. (1-1) When reaching the xy plane through the opening ABC on the bottom surface, the reaching point draws a curve from the above consideration. (1-2) When reflected by the spherical mirror ABF, there are the following seven possible behaviors of reflected light rays. (1-2-1) When reaching the xy plane through the opening ABC on the bottom surface, the reaching point draws a curve from the above consideration. (1-2-2) When the light is reflected by the spherical mirror DFE, it is the same as the above (1). (1-2-3) When the light is reflected by the spherical mirror ADC, it is the same as the above (1-3). (1-2-4) When reflected by the spherical mirror BCE, it is the same as the above (1-4). (1-2-5) When reflected by the plane mirror AFD, it is the same as the above (1-5). (1-2-6) When reflected by the plane mirror CDE, it is the same as (1-6) above. (1-2-7) When reflected by the plane mirror BEF, it is the same as the above (1-7).

(1-3) When the light is reflected by the spherical mirror ADC, it is the same if the spherical mirror ADC of (1-2-3) in the above (1-2) is replaced with a spherical mirror ABF due to the symmetry. (1-4) When reflected by the spherical mirror BCE, it is the same if the spherical mirror BCE of (1-2-4) in (1-2) is replaced by the spherical mirror ABF due to symmetry.

(1-5) When reflected by the plane mirror AFD, there are the following seven possible behaviors of the reflected light rays. (1-5-1) When reaching the xy plane through the opening ABC on the bottom surface, the reaching point draws a curve or a straight line from the above consideration. (1-5-2) When reflected by the spherical mirror DFE, it is the same as the above (1). (1-5-3) When reflected by the spherical mirror ADC, it is the same as (1-3) above. (1-5-4) When reflected by the spherical mirror BCE, it is the same as the above (1-4). (1-5-5) When the light is reflected by the spherical mirror ABF, it is the same as the above (1-2). (1-5-6) When reflected by the plane mirror CDE, it is the same as the above (1-6). When reflected by the (1-5-7) plane mirror BEF, it is the same as the above (1-7).

(1-6) When reflected by the plane mirror CDE, due to the symmetry of the light reflecting device 10, the plane mirror CDE of the above (1-5-6) in the above (1-5) is replaced by the plane mirror DFE.
It is similar if replaced with. When the light is reflected by the (1-7) plane mirror BEF, the same result is obtained by replacing the plane mirror BEF of (1-5) in (1-5) with the plane mirror AFD due to the symmetry of the light reflecting device 10.

(2) When reflected by the spherical mirror ABF,
In this case, there are the following six possible behaviors of reflected light rays. (2-1) When the light is reflected by the spherical mirror DFE, it is the same as the above (1). (2-2) When the light is reflected by the spherical mirror ADC,
-3) is the same. (2-3) When the light is reflected by the spherical mirror BCE, (1)
It is the same as -4). (2-4) When reflected by the plane mirror AFD, the above (1)
It is the same as -5). (2-5) When reflected by the plane mirror CDE, the above (1)
It is the same as -6). (2-6) When reflected by the plane mirror BEF, (1)
It is the same as -7).

(5) When reflected by the plane mirror AFD,
It is the same as the above (1-5). However, the above (1-5
In the case of 1), the reaching point always draws a straight line from the above consideration.

As a result of the above consideration, the xy plane is filled with approximately 7 ⁿ finite-length or semi-infinite curves or line segments as an effect of the group of light rays that are reflected to the outside after being reflected n times inside the device. Be done. As described above, the number of curves appearing on the xy plane increases exponentially with respect to the number of reflections inside the device and covers the xy plane. A light beam that has entered the device through the opening ABC on the bottom surface by fixing the position of the emitted light beam and changing the direction within a certain plane or by fixing the output direction and moving the position in parallel is It can be seen that the internal multiple reflections approach an arbitrary point on the xy plane as the number of reflections inside the device increases. That is, it can be seen that when the incident light beam to the device is constrained in the plane and changed, the output light beam from the device has a two-dimensional spread (change) in the xy plane.

As described above, according to the embodiment of the present invention, when performing the optical space communication using the optical signal such as the infrared ray, the transmitting side searches for the receiving side to establish the communication. Although it is necessary, by using the light reflecting device 10, the optical path connecting the transmitter and the receiver can be found in a short time, so that the time until the communication is established can be shortened. Therefore, the search for the optical path from the optical transmitter to the optical receiver can be performed in a shorter time than the conventional example, the configuration is simple and inexpensive, and the optical space communication can be performed simultaneously between a plurality of transmitters and receivers. You can

In the above embodiment, the light reflecting device 10 is used.
Although an optical signal is used as a signal reflected by, the present invention is not limited to this, an electromagnetic wave having a relatively short wavelength, such as a quasi-millimeter wave or millimeter wave, which can be reflected by a mirror surface, or a signal having a wavelength such as infrared May be used.

[0071]

As described above in detail, according to the light reflecting device of the first aspect of the present invention, the light reflection for reflecting the optical signal transmitted from the optical transmitter and transmitting it to the optical receiver. A device, wherein each center of four hollow spherical mirrors each having the same diameter as each side of the regular tetrahedron and having a mirror surface on at least the outer surface is located at each vertex of the virtual regular tetrahedron. And mounting the four spherical mirrors so that each two spherical mirrors of the four spherical mirrors come into contact with each other at one point, and then three spherical surfaces are selected from the four spherical mirrors. The four spherical mirrors when the mirrors are selected as one group are three spherical mirrors of the first, second, third, and fourth groups, and the centers of the three spherical mirrors of the first group are set. Cutting in a first plane passing through the first plane of the three spherical mirrors on the first plane. Is passed through each of the centers of a first plane mirror that is fitted in a plane formed by the three curves formed by and that has at least a mirror surface facing the inside of the regular tetrahedron, and three spherical mirrors of the second set. A mirror surface facing the inner side of the regular tetrahedron, which is cut in the second plane to be fitted and is fitted into the plane formed by the three curves formed by the second set of three spherical mirrors on the second plane. Second having at least
Plane mirror and a third plane passing through the respective centers of the three spherical mirrors of the third set are cut to form a third set of three spherical mirrors on the third plane. A third plane mirror fitted into a plane formed by three curves and having at least a mirror surface facing the inside of the regular tetrahedron, and a fourth plane mirror passing through respective centers of the three spherical mirrors of the fourth set. An opening having a plane formed by three curves formed by the fourth set of three spherical mirrors on the fourth plane, and the four spherical mirrors by the first plane. A first, a second, a third, and a fourth spherical mirror formed by being cut along the second, third, and fourth planes, respectively, and when an optical signal is incident through the opening, The optical signal is the first
And at least one of the second, third and fourth spherical mirrors and the first, second and third plane mirrors is reflected and emitted through the opening. . Therefore, when performing space optical communication using an optical signal, it is necessary for the transmitting side to search for the receiving side in order to establish communication. However, when the light reflecting device of the present invention is used, the transceiver Since it is possible to discover the optical path connecting the two, it is possible to shorten the time until the communication is established. Therefore, the search for the optical path from the optical transmitter to the optical receiver can be performed in a shorter time than the conventional example, the configuration is simple and inexpensive, and the optical space communication can be performed simultaneously between a plurality of transmitters and receivers. You can

According to the optical space communication system of the second aspect of the present invention, the light reflecting device of the first aspect,
At least one optical transmitter that emits an optical signal so as to pass through the opening of the light reflecting device, and the optical reflection after the optical signal from the optical transmitter passes through the opening of the light reflecting device Light reflected by at least one of the first, second, third, and fourth spherical mirrors of the device and the first, second, and third plane mirrors, and emitted through the opening. At least one optical receiver for receiving signals. Therefore, when performing the optical space communication using the optical signal, it is necessary to search the receiving side on the transmitting side to establish the communication.
By using the light reflecting device of the present invention, the optical path connecting the transmitter and the receiver can be found in a short time, so that the time until the establishment of communication can be shortened. Therefore, the search for the optical path from the optical transmitter to the optical receiver can be performed in a shorter time than the conventional example, the configuration is simple and inexpensive, and the optical space communication can be performed simultaneously between a plurality of transmitters and receivers. You can

[Brief description of drawings]

FIG. 1 is a light reflection device 1 according to an embodiment of the present invention.
A light reflection device 1 in which 0 is viewed obliquely from the front of the plane mirror AFD
It is a perspective view which shows the external appearance of 0.

FIG. 2 illustrates a light reflecting device 10 according to the present embodiment, which is a spherical mirror D.
FIG. 3 is a plan view showing the outer appearance of the light reflecting device 10 as seen from above the EF.

FIG. 3 shows an opening A of the light reflecting device 10 according to the present embodiment.
It is a bottom view when it faces toward BC.

FIG. 4 is a side view of the light reflecting device 10 according to the present embodiment as viewed toward the spherical mirror ADC.

FIG. 5 is a side view of the light reflecting device 10 according to the present embodiment as viewed toward the plane mirror AFD.

FIG. 6 is a perspective view showing a first step of a manufacturing process of the light reflecting device 10 of the present embodiment.

FIG. 7 is a plan view showing a second step of the manufacturing process of the light reflecting device 10 of the present embodiment.

FIG. 8 is a bottom perspective view showing a third step of the manufacturing process of the light reflecting device 10 of the present embodiment.

9 is a perspective view corresponding to FIG. 1 and showing a reflected light ray in the first reflection case. FIG.

FIG. 10 is a diagram corresponding to FIG. 1, and is a perspective view showing reflected light rays in the second reflecting case.

FIG. 11 is a perspective view corresponding to FIG. 1 and showing a reflected ray in a third reflecting case.

FIG. 12 is a perspective view corresponding to FIG. 1 and showing a reflected ray in a fourth reflecting case.

FIG. 13 is a diagram corresponding to FIG. 1 and is a perspective view showing a reflected ray in a fifth reflecting case.

FIG. 14 is a diagram corresponding to FIG. 1 and is a perspective view showing a reflected ray in a sixth reflecting case.

15 is a perspective view corresponding to FIG. 1 and showing a reflected ray in a seventh reflection case. FIG.

16 is a perspective view corresponding to FIG. 1 and showing a reflected ray in an eighth reflecting case. FIG.

FIG. 17 is a perspective view corresponding to FIG. 1, showing a reflected ray of light in a ninth reflecting case.

FIG. 18 is a perspective view corresponding to FIG. 1 and showing a reflected light ray in a tenth reflecting case.

FIG. 19 is a perspective view showing an arrangement of the light reflecting device 10 in the room 90 used in the optical space communication system of the example of the present embodiment.

FIG. 20 is a plan view showing a position where the optical signal can be received on the bottom surface of the room 90 when the optical signal is transmitted from the transmitting side terminal device in the optical space communication system of the first example of the present embodiment. .

FIG. 21 is a plan view showing a position where the optical signal can be received on the bottom surface of the room 90 when the optical signal is transmitted from the transmission side terminal device in the optical space communication system of the second example of the present embodiment. .

FIG. 22 is a plan view showing a position where the optical signal can be received on the bottom surface of the room 90 when the optical signal is transmitted from the transmitting side terminal device in the optical space communication system of the third example of the present embodiment. .

FIG. 23 is a plan view showing a position where the optical signal can be received on the bottom surface of the room 90 when the optical signal is transmitted from the transmitting side terminal device in the optical space communication system of the fourth example of the present embodiment. .

FIG. 24 is a plan view showing a position where the optical signal can be received on the bottom surface of the room 90 when the optical signal is transmitted from the transmitting side terminal device in the optical space communication system of the fifth example of the present embodiment. .

FIG. 25 is a plan view showing a position where the optical signal can be received on the bottom surface of the room 90 when the optical signal is transmitted from the transmission side terminal device in the optical space communication system of the sixth example of the present embodiment. .

FIG. 26 is a block diagram showing one transmission side terminal device 50-1 to the light reflection device 10 in the optical space communication system according to the first embodiment.
It is a perspective view which shows the state at the time of transmitting an optical signal toward one receiving side terminal device 50-11 via the.

FIG. 27 is a diagram illustrating one optical transmission terminal device 50-1 to one optical reflection device 10 in the optical space communication system according to the second embodiment.
Via the three receiving side terminal devices 50-11, 50-1
It is a perspective view which shows the state at the time of transmitting an optical signal toward 2, 50-13.

FIG. 28 is a diagram illustrating three transmission side terminal devices 50-1, 50-2, 50- in the optical space communication system according to the third embodiment.
3 to the three receiving side terminal devices 5 via the light reflecting device 10.
It is a perspective view which shows the state when transmitting an optical signal toward 0-11, 50-12, 50-13.

FIG. 29 is a block diagram showing the configuration of an optical space communication terminal device 50 for the optical space communication system of the present embodiment.

FIG. 30 is a perspective view of a plane mirror A _{j + 1} used to show the reflection process of the light reflecting device 10 of the present embodiment.

FIG. 31 is a perspective view of a spherical mirror S _{j + 1} used to show the reflection process of the light reflecting device 10 of the present embodiment.

[Explanation of symbols]

10 ... Light reflecting device, 50 ... Optical space communication terminal device, 51 ... a personal computer, 52 ... keyboard, 53 ... CRT display, 54, 57 ... Interface, 55 ... laser diode, 56 ... Photoelectric converter, 58 ... beam splitter, 59 ... Light emitter, 59a ... Collimating lens, 90 ... room, ADC, ABF, BCE, DFE ... spherical mirror, AFD, BEF, CDE ... Plane mirror, ABC ... opening, SM1, SM2, SM3, SM4 ... spherical mirror, O1, O2, O3, O4 ... Center of spherical mirror, RT1 ... Regular tetrahedron, T1, T2, T3, T4 ... The vertices of a regular tetrahedron.

Claims (2)

(57) [Claims] 1. A light reflecting device for reflecting an optical signal transmitted from an optical transmitter and transmitting the optical signal to an optical receiver, wherein each vertex of a virtual tetrahedron is provided with each side of the regular tetrahedron. The center of each of the four hollow spherical mirrors having the same diameter as the above and at least a mirror surface on the outer surface is located, and each two spherical mirrors of the four spherical mirrors are at one point. After the four spherical mirrors are mounted so as to be in contact with each other, three spherical mirrors are selected from the four spherical mirrors as one set, and the four spherical mirrors are first set.
And a second, a third, and a fourth set of three spherical mirrors, cut on a first plane passing through the centers of the three spherical mirrors of the first set, and on the first plane. A first plane mirror having at least a mirror surface fitted into the plane formed by the three curves formed by the first set of three spherical mirrors, and facing the inside of the regular tetrahedron; and the second set. Cut in a second plane passing through each of the centers of the three spherical mirrors, and fitted into the plane formed by the three curves formed by the second set of three spherical mirrors on the second plane. A second plane mirror having at least a mirror surface facing the inside of the regular tetrahedron and a third plane passing through the respective centers of the three spherical mirrors of the third set, and cutting the third plane mirror. Fit into the plane formed by the three curves formed by the third set of three spherical mirrors on the plane A third plane mirror having at least a mirror surface facing the inside of the regular tetrahedron and a fourth plane passing through the respective centers of the three spherical mirrors of the fourth set are cut to obtain the fourth plane. An opening having a plane formed by three curves formed by the above-mentioned fourth set of three spherical mirrors; and the four spherical mirrors in the first, second, third and fourth planes. 1st, 2nd and 3rd formed by cutting respectively
And a fourth spherical mirror, and when an optical signal is incident through the opening, the optical signal includes the first, second, third and fourth spherical mirrors and the first and second spherical mirrors. And a third plane mirror, which is configured to reflect at least one mirror and emit the light through the opening. 2. The light reflecting device according to claim 1, at least one optical transmitter that emits an optical signal so as to pass through an opening of the light reflecting device, and an optical signal from the optical transmitter. After passing through the opening of the light reflecting device, the first, second, third and fourth of the light reflecting device are provided.
A spherical mirror and at least one optical receiver for receiving an optical signal reflected by at least one of the first, second and third plane mirrors and emitted through the opening. An optical space communication system characterized by being provided.