JPH08223116A - Optical space transmission equipment - Google Patents

Abstract

PURPOSE: To adjust the optical axis of an optical space transmission equipment with a high precision by the constitution which has no mechanical mobile parts. CONSTITUTION: An optical axis varying optical device 8 is provided being in contact with a lens ID for transmission and reception on the space transmission line side of the lens ID. With respect to the optical axis varying optical device 8, each of two optical elements has liquid crystal sealed up between two transparent substrates assuming a wedge shape and an arbitrary vertical angle and changes the refractive index of liquid crystal by applying a voltage to transparent electrodes formed in the inside faces of transparent substrates, and vertical angles of wedge shapes are inverted by 180 deg. to compose these optical elements, and optical elements correspond to two orthogonal axial directions in the face perpendicular to the optical axis. The deviation in the optical axis is discriminated from the convergence position information on a position detection element 5 of incident light L2 by a convergence position detection circuit 14 and a CPU 15, and the voltage is controlled based on the discrimination result by a driving circuit 16, thus adjusting the optical axis.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical space transmitter using laser light as a signal light source, and more particularly to adjustment of an optical axis between the optical space transmitters.

[0002]

2. Description of the Related Art First of all, an optical space transmission device is a transmission side that modulates transmission information into a change in the intensity of light, emits the modulated light into the atmosphere toward the reception side, and the reception side uses the transmission side. By receiving and demodulating the modulated light emitted from, the desired information signal is transmitted through the atmospheric space.

That is, as shown in FIG. 8, the optical space transmission performed between one optical space transmission apparatus 50A and the other optical space transmission apparatus 50B is transmitted from one optical space transmission apparatus 50A (or 50B). Lens 1 with laser light modulated by signal
It is realized by emitting (emitted light L1) via D and receiving similarly modulated laser light (incident light L2) from the other optical space transmission device 50B (or 50A) via the lens 1D. .

Although FIG. 8 shows an optical space transmission device having a transmission and reception integrated structure, many devices (not shown) in which the transmission function and the reception function are separated from each other have been proposed so far. , Has been put to practical use.

However, since the light beam is absorbed and attenuated by rain, fog, fine particles, etc. in the atmosphere which is the transmission path, in order to always ensure sufficient optical power on the receiving side, on the transmitting side, I had to prepare a lot of optical power.

Further, the optical beam path fluctuates due to fluctuations in the atmosphere, changes in temperature gradient, etc., and this effect becomes greater as the transmission section becomes longer. Further, even at a place where the optical free space transmission device is installed, for example, on the roof of a building, the building itself is deformed by a change in ambient temperature, although it is minute, and the emission direction of the light beam is changed. Therefore, it is necessary to increase the diameter of the light beam in order to prevent the light beam from coming off the receiving device, and from this point as well, it is necessary to increase the optical power on the transmission side.

On the other hand, however, the unit power density is regulated by the light wavelength from the viewpoint of eye safety measures, and it is strict especially in the visible light band. From this point, it is not always possible to prepare sufficient light power on the transmitting side. It was

As countermeasures against these problems, the applicants of the present application have introduced an automatic control technique, and have proposed a mechanism in which a light beam always reaches the partner device regardless of the installation location of the device or the state of the transmission path. An example thereof is shown in FIGS. 9 to 1.
This will be described with reference to FIG. The optical free space transmission apparatus shown in FIG. 9 has a structure in which the functions of transmission and reception are integrated, and by installing the same apparatus facing each other, it is possible to perform bidirectional information transmission.

FIG. 9 shows a block diagram of the optical space transmission device. First, the optical system of the optical space transmission device includes a semiconductor laser 3 as a light source, a lens 1A for converting a laser beam into a parallel beam, and a polarization beam splitter 2 for separating light.
A, a lens 1B and a lens 1D for emitting a laser beam into substantially parallel light, a polarizing beam splitter 2B and a lens 1C for converging incident light on the photodetector 4, and further for adjusting the optical axis. The position detecting element 5 and a lens 1E that collects light on the position detecting element 5 are included. The optical element is integrally configured, and its constituent body is fixed to the housing of the apparatus via a rotary shaft having a structure described later.

Next, the electric circuit drives a laser driving circuit 18 for driving the semiconductor laser 3 in accordance with the modulated transmission signal,
The light receiving circuit 19 which receives the output signal from the light detecting element 4, the condensing position detecting circuit 14 which receives the output signal from the position detecting element 5, and the motor drive circuit 23 are controlled based on the signals of the condensing position detecting circuit 14. It is composed of a CPU 15 and the like. The motor drive circuit 23 drives the optical system with two axes orthogonal to each other in a plane perpendicular to the emission optical axis, for example, an X-axis motor 24 and a Y-axis motor 25 which rotate in a horizontal direction and a vertical direction.

The operation of the above-described optical space transmission device will be briefly described. As a transmitter, a circuit (not shown) in the preceding stage of the laser drive circuit 18 modulates information to be transmitted into a transmission signal, and the laser drive circuit 18 is modulated based on the modulation signal.
Drives the semiconductor laser 3 to modulate the laser light to a light intensity corresponding to the modulation signal. Next, the laser light is passed through the lens 1A, the polarization beam splitter 2A, and the lens 1B.
And the lens 1D to convert the light into substantially parallel emitted light L1 and send it to the receiving device.

The operation as a receiver is that the laser light sent from the other device, that is, the incident light L2 is received by the lens 1D and is condensed on the photodetector 4 through the polarization beam splitters 2A, 2B and the lens 1C. An optical signal is converted into an electric signal by the photo-detecting element 4, and is demodulated into original information by the light receiving circuit 19 and a subsequent circuit (not shown) subsequent thereto.

Here, the structure of the position detecting element 5 and the rotating shaft described above will be described, and the optical axis adjusting method of the above-described optical space transmission device will be described based on this.

First, the position detecting element 5 has the structure shown in FIG. 10, and the light receiving surface 41 thereof has a two-dimensional spread having four distinct sides, and electrodes X1, X2, Y1, respectively on each side.
Y2 is provided. Each pair of opposite sides is an electrode of one axis (for example, X axis), and the other pair of sides orthogonal to this is an electrode of one axis (for example, Y axis).

Here, the center of the light receiving surface 41 is the origin P ₀ (0,
0), the converging point of the light 40 is P (X, Y), and the output currents in the X-axis and Y-axis directions generated by the light irradiation are individually measured. That is, the output current of the electrode X1 is changed to IX1 for each electrode.
, The output current of the electrode X2 is IX2, the output current of the electrode Y1 is IY1, the output current of the electrode Y2 is IY2, and the length of each side is 2D ₀ , the focal point is P ₁ (X, Y)
As is well known, is calculated as _{X = D 0 (IX2 -IX1)} / (IX2 + IX1) Y = D 0 (IY2 -IY1) / (IY2 + IY1). Therefore, the focus position of the light receiving surface 41 can be determined by calculating the output current from the position detecting element 5 described above.

Next, as shown in FIG. 11, the structure of the rotation axis is such that the optical system is perpendicular to the exit optical axis in a plane perpendicular to the exit optical axis.
It has a structure in which it rotates about one axis, for example, the horizontal direction and the vertical direction. A lens barrel 30 equipped with an optical system including a lens 1D
Is rotatably held by an inner frame 31 via a Y rotation shaft 29, and the inner frame 31 is rotatably held by an outer frame 32 via an X rotation shaft 28. Is fixed to a fixed portion (not shown) of the device. The X-axis gear 26 is fixed to the X-rotation shaft 28, and the rotation of the X-axis motor 24 fixed to the outer frame 32 is transmitted to the X-rotation shaft 28. Similarly, the Y-axis gear 27 is fixed to the Y-rotation shaft 29, and the rotation of the Y-axis motor 25 fixed to the inner frame 31 is transmitted to the Y-rotation shaft 29.

The optical axis adjustment of the above-described optical space transmission device has been performed as follows. The transmitted light from the partner device, that is, the incident light L2 is received by the lens 1D and is condensed on the position detection element 5 through the polarization beam splitters 2A, 2B and the lens 1E. The condensing position can be recognized as the X and Y coordinates on the position detecting element 5 as described above. This coordinate corresponds to the incident angle of the incident light L2.

The position detecting element 5 has its origin P ₀ (0, 0, _{0 at the} position where the incident light L 2 is condensed when the optical axes of the devices coincide with each other.
0) should be set. However, in general, the focusing point PXY ₀ (X ₀ , Y ₀ ) when the optical axes coincide with each other, which is difficult to adjust, is set as a reference position, and the position is stored in the CPU 15. Next, when the optical axis is deviated for some reason, the focus position P (X, Y) at this time is detected by the focus position detection circuit 14, and the stored reference focus point PXY ₀ (X _0). , Y ₀ ) and CP
Compared with U15, the X-axis motor 24 and the Y-axis motor 25 are driven by the motor drive circuit 23 by the driving force corresponding to the difference in the position distance, and the optical axis of the optical system is adjusted. By performing this control by each of the two devices connecting the lines, the optical axes can always be held in alignment with each other.

Therefore, in the above-mentioned method, the optical axis is constantly adjusted effectively, and the light beam can be narrowed down. Therefore, the optical power on the transmitting side can be contained within a narrow beam, and the optical power in the atmosphere can be reduced. It is possible to cope with the reduction of the optical power in the receiving device due to the absorption of light such as rain, fog, and particles. Further, it is possible to prevent the light beam from coming off the receiving device by automatic control with respect to fluctuations in the light beam path due to fluctuations in the atmosphere, changes in temperature gradient, and the like.

However, in order to accurately perform the above-mentioned optical axis control, a highly accurate rotating shaft is required, which is an expensive and large device, and the optical system as a whole constantly swings. It is necessary to take sufficient measures to secure the members. In addition, since a mechanism for protecting the rotating shaft during transportation is required and a swing space for the entire optical system is required, the entire apparatus may be large and heavy.

[0021]

SUMMARY OF THE INVENTION Therefore, the object of the present invention is to make the optical axis adjusting mechanism between the devices of the optical space transmission device small in size and highly reliable without mechanically moving parts so that it can be continuously used for a long period of time. In addition to ensuring further reliability, the device is lightweight and small in size to simplify maintenance work.

[0022]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an optical device in which two optical elements in which the refractive index of light changes according to an applied voltage is laminated is provided. The two refraction directions of the optical device are arranged so as to coincide with each other in two axial directions orthogonal to the optical axis of the optical device, and the refractive index of the optical device is controlled according to the incident angle of incident light. Then, adjust the optical axis of the optical system.

The optical axis of the optical system is adjusted by controlling the refractive index of the optical device on the basis of the incident angle information of the laser beam on the other device included in the transmitted signal.

In the optical device, two transparent substrates having an arbitrary apex angle are bonded to each other, a liquid crystal is sealed between the transparent substrates, and a refractive index is applied by a voltage applied between electrodes provided on the transparent substrate. It has a wedge-shaped configuration in which

In the optical device, two transparent substrates having an arbitrary apex angle are joined to each other, liquid crystal is sealed between the transparent substrates, and a voltage is applied between electrodes provided on the transparent substrates. The above problem is solved by adopting a configuration in which two wedge-shaped optical elements whose refractive indexes are changed are surface-bonded by inverting the wedge-shaped apex angle by 180 degrees.

[0026]

By applying a voltage to the optical device according to the amount of deviation of the optical axis to change the refractive index and adjust the optical axis, an optical axis adjusting device having no mechanically movable portion is realized. In addition to being capable of high-speed and high-precision control, the number of component parts of the device is small, so that the device is small and lightweight, and is excellent in portability. Further, the manufacturing is easy, the cost can be reduced, and the maintenance work can be simplified.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIGS. First, the principle of the optical axis variable optical device forming the main constituent part of the present invention will be described with reference to FIG. The optical axis variable optical device utilizes the characteristic that the refractive index of the liquid crystal changes when a voltage is applied to the liquid crystal, and its principle configuration is flat and transparent as shown in FIG. A transparent electrode 12 is formed on one surface of a substrate 11, the transparent electrodes 12 are opposed to each other, and the liquid crystal 1 is interposed therebetween.
0 is enclosed and a voltage V is applied between the transparent electrodes 12 to change the refractive index n of the liquid crystal 10.

The refractive index n shown in FIG. 7A is n = sin θ
/ Sin θ _n . FIG. 7B shows an example of the relationship between the applied voltage V and the refractive index n.
It is shown that the refractive index changes from n1 (for example, 1.5) to n2 (for example, 1.8) when changing from V2 to V2.

In the optical axis variable optical device used in the embodiments described below, the two transparent substrates 11 are bonded together with an arbitrary apex angle, and the liquid crystal 10 is sealed between them. It has a structure, and is constructed by combining a plurality of them.

Embodiment 1 The configuration of the first embodiment of the optical free space transmission apparatus according to the present invention will be described with reference to FIGS. 1 to 3. The apparatus shown in FIG. 1 has a transmission / reception integrated configuration, and includes at least a semiconductor laser 3, branch optical elements 6A and 6B, a transmission / reception lens 1D,
The light detecting element 4 and the position detecting element 5B are included. Further, the above-mentioned optical axis variable optical device 7 is disposed in close contact with the space transmission path side of the lens 1D. The optical axis variable optical device 7 includes two axially orthogonal component elements 7X (for example, horizontal direction) and 7Y in a plane perpendicular to the optical axis L.
(For example, in the vertical direction).

As shown in FIG. 2, the constituent unit of the optical axis variable optical device 7 has two transparent substrates 11 with an arbitrary angle θ.
_The liquid crystal 10 is sealed with ₀ , and the liquid crystal 10 is sealed between them. Transparent electrodes 12 are provided on the opposite surfaces of the transparent substrate 11, and a voltage V is applied between the electrodes. The operation is such that, when light is vertically incident on one of the transparent substrates 11 from the atmosphere, it is incident on the other transparent substrate 11 through the liquid crystal 10 at an angle θ ₀ , and the effect of refraction by the liquid crystal 10 is added to the angle θ _0. It emits to the atmosphere with + θ ₁ . At this time, the refractive index n of the liquid crystal 10 is n = sin θ ₀ / sin (θ ₀ + θ ₁ ).

Here, when θ ₀ is small, n = θ ₀ / θ ₀ + θ _{1 is} approximated, θ _{0 is set} to 3 degrees, the voltage V is changed, and the refractive index n is 1.5 to 1. If you change it to 8,
₁ changes in the same direction from 1.5 degrees to 2.4 degrees.

FIG. 3 shows the configuration of the optical axis variable optical device 7. FIG. 3A shows the arrangement of the optical axis variable optical device 7X in the X-axis direction (for example, the horizontal direction) and the refraction direction of incident light. Also,
FIG. 11B shows the arrangement of the optical axis variable optical device 7Y in the Y-axis direction (for example, the vertical direction) and the refraction direction of the incident light, and FIG. 7 shows that the direction of the optical axis can be adjusted arbitrarily.

The control of the variable optical axis device 7 is performed as described below. First, the light transmitted from the other device, that is, the incident light L1 is the optical axis variable optical device 7 and the lens 1.
The light is focused on the position detection element 5 through D and the branch optical elements 6A and 6B. As described in the conventional example, the position detecting element 5 outputs a signal corresponding to the condensing position, the condensing position detecting circuit 14 processes the signal, and inputs the signal to the CPU 15. Reference light-condensing position information when the optical axes coincide with each other is stored in advance in the CPU 15, the reference information is compared with the actual light-condensing position information, and a signal corresponding to the difference is output to the drive circuit 1.
6, the drive circuit 16 applies a voltage to the liquid crystal of the optical axis variable optical device 7 to change its refractive index and adjust the optical axis.

In the present embodiment, the output optical axis has a certain deviated angle with respect to the optical axis of the optical system because of the wedge-shaped structure of the optical axis changing optical device 7. Further, the changing direction of the optical axis due to refraction is one direction, and therefore, the central optical axis thereof needs to be set at the center of the refraction angle range of the liquid crystal 10.

Second Embodiment The configuration of a second embodiment of the optical free space transmission apparatus according to the present invention will be described with reference to FIGS. 4 to 6. The apparatus shown in FIG. 4 has a transmission / reception integrated configuration, and the configuration of the optical system and the electrical circuit configuration are different from those of the first embodiment in the configuration of the optical axis variable optical device. Therefore, the same components are designated by the same reference numerals and the description thereof will be omitted.

Optical axis variable optical device 8 which is a feature of this embodiment.
As shown in FIG. 5, the unit of the optical axis variable optical device shown in FIG. 2 is used as one constituent member, the apex angle is inverted by 180 degrees, and the surfaces of the two units are joined. Therefore, the principle of changing the optical axis will be described with reference to FIG.
Is the same as that described in.

Next, the change of the optical axis of the optical axis changing optical device 8 will be described with reference to FIG. The two transparent substrates 111 and 112 are bonded at an angle θ ₀ ,
The liquid crystal 10 is enclosed between them. The transparent substrate 11
A transparent electrode 121 is provided on the opposite surfaces of 1 and 112, and a voltage V1 is applied between the electrodes. Further, the two transparent substrates 112 and 113 are also bonded at an angle θ ₀ , and the liquid crystal 10 is sealed between them. A transparent electrode 122 is provided on the opposite surfaces of the transparent substrates 112 and 113, and a voltage V2 is applied between the electrodes.
Is applied. Therefore, the optical axis variable optical device 8 of this example
The transparent substrates 111 and 113 are parallel to each other, but the two apex angles θ ₀ do not necessarily match.

FIG. 5 shows the refraction of light when the refractive index n ₂ is larger than n _1.
1 is perpendicularly incident on the transparent substrate 11 through the liquid crystal 10.
2 to enter at an angle theta _0, enter the next stage unit at an angle theta ₀ - [theta] ₂₁ subjected to any effect of the refraction by the liquid crystal 10 further includes a transparent substrate 113 when emitted with a theta ₁₁ to the atmosphere n ₁ sin [theta ₀ = N ₂ sin θ ₂₁ n ₂ sin (θ ₀ −θ ₂₁ ) = sin θ ₁₁ , and when the angle is small, approximately n ₁ θ ₀ = n ₂ θ ₂₁ n ₂ (θ ₀ −θ ₂₁ ) = θ ₁₁ Can be represented. Therefore, θ ₁₁ = (n ₂ −n ₁ ) θ ₀ is obtained. When the refractive index n ₂ is smaller than n ₁ , the refraction direction of light is opposite to the direction shown in FIG.

Therefore, similarly to the first embodiment, the angle θ _{0 is set} to 3 degrees, and the applied voltages V 1 and V ₂ of the respective elements are changed so that the refractive indexes n ₁ and n ₂ are independently 1.5 to 1.8. Θ ₁₁ changes from +0.9 degrees to −0.9 degrees.
It can be changed to both sides of the optical axis in the range of degrees.

FIG. 6 shows the configuration of the optical axis variable optical device 8. FIG. 6A shows the arrangement of the optical axis variable optical device 8X in the X-axis direction (for example, the horizontal direction) and the refraction direction of incident light. Also,
The same figure (b) shows the arrangement of the optical axis variable optical device 8Y in the Y-axis direction (for example, the vertical direction) and the refraction direction of the incident light, and the same figure (c) shows the variable axis optical device in which the two optical devices are combined. 8 shows that the direction of the optical axis can be arbitrarily adjusted. The control of the optical axis variable optical device 8 is the same as the method described in the first embodiment, but the light can be swung in both the positive and negative directions about the optical axis of the optical system, The optical axis is easier to control.

In the first and second embodiments described above, the deviation of the optical axis is controlled by collecting and detecting the incident light from the partner device on the position detecting element 5, but another method, for example, Information such as the incident angle of the light to be transmitted to the other device is transmitted in addition to the transmission information of the other device, and the received light is demodulated and the optical axis variable optical device is controlled based on the information. Is also good.

Further, as the transparent substrate of the optical axis variable optical devices 7 and 8 described above, a plastic plate such as an acrylic plate or a transparent ceramic plate may be used in addition to the glass plate. Further, the transparent substrate includes a coated substrate and a colored substrate having wavelength selectivity for wavelengths such as infrared rays and ultraviolet rays in addition to visible light. Further, the transparent substrate is not limited to a parallel plate, and may be composed of an optical prism having an apex angle or an optical member having another optical effect such as a lens effect.

The liquid crystal to be sealed is not limited to the cyanobiphenyl mixed system E7, but nematic liquid crystal, mixed system, etc.
Any liquid crystal having an electro-optical effect (electric field control refraction effect) may be used.

Furthermore, the optical axis variable optical devices 7 and 8 are not limited to being arranged on the space transmission path side of the lenses for transmission and reception, but may be set inside the optical system.

The optical space transmission apparatus described above has been described as a system in which the optical system for transmission and the optical system for reception are shared, but the transmission optical system and the reception optical system are configured separately from each other.
The optical device for optical axis adjustment described above may be used in the optical space transmission device in which the transmission and reception are integrated in one housing, and only the device having only the transmission function and the reception function may be used. It is needless to say that it may be used in an optical space transmission device that is completely separated from the device that it has.

[0047]

As described above, according to the present invention, the optical axis adjusting mechanism between the devices of the optical space transmission device can be constituted by the optical parts having no mechanically movable parts, and the oscillating space of the optical system is unnecessary. Thus, a lightweight optical space transmission device can be realized. Further, the reliability can be further improved, and therefore maintenance work can be simplified, which is suitable for long-term continuous use.

Since the number of optical components is reduced, the beam loss due to the absorption of the optical power in the device and the loss of a part of the optical beam from the optical component is reduced, and the optical transmission can be performed with high efficiency.

It is possible to eliminate the electric power required for controlling the mechanically movable part, and therefore the power source can be made small, and a battery-operated device having excellent portability can be realized. .

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of an optical free space transmission apparatus according to the present invention.

FIG. 2 is a diagram illustrating a configuration of a unit of an optical axis variable optical device used in the first embodiment and an optical axis change.

3A and 3B are perspective views showing changes in the optical axis by the optical axis variable optical device used in the first embodiment, where FIG. 3A is the X-axis direction, FIG. 3B is the Y-axis direction, and FIG. The combined direction of the axis and the Y-axis is shown.

FIG. 4 is a block diagram showing a second embodiment of the optical free space transmission apparatus according to the present invention.

FIG. 5 is a diagram illustrating a configuration of an optical axis variable optical device unit used in a second embodiment and optical axis changes.

6A and 6B are perspective views showing changes in the optical axis by the optical axis variable optical device used in the second embodiment, where FIG. 6A is the X-axis direction, FIG. 6B is the Y-axis direction, and FIG. The combined direction of the axis and the Y-axis is shown.

FIG. 7 is a characteristic diagram for explaining a change in refractive index of liquid crystal, in which (a) is a schematic diagram of refractive index measurement and (b) is a schematic diagram.
Shows an example of the applied voltage and the refractive index of the liquid crystal.

FIG. 8 is a diagram for explaining a transmission state of the optical free space transmission apparatus.

FIG. 9 is a block diagram showing an example of a conventional space optical transmission apparatus.

FIG. 10 is a perspective view for explaining a position detection element used for automatic control of a laser light emission direction of an optical space transmission device.

FIG. 11 is a front view for explaining the configuration of a rotating shaft used for controlling the optical axis of the optical space transmission device.

[Explanation of symbols]

 1A to 1D Lens 2A, 2B Polarization beam splitter 3 Semiconductor laser 4 Photodetector 5 Position detector 6A, 6B Branch optical element 7, 8 Optical axis variable optical device 10 Liquid crystal 11 Transparent substrate 12, 121, 122 Transparent electrode 14 Condensing Position detection circuit 15 CPU 18 Laser drive circuit 19 Light receiving circuit 23 Motor drive circuit 24 X axis motor 25 Y axis motor 26 X axis gear 27 Y axis gear 28 X rotation axis 29 Y rotation axis 31 Inner frame 32 Outer frame

Claims (19)

[Claims] 1. A transmission unit including a transmission optical system that uses laser light as a signal light source, modulates the laser light according to a transmission signal, and emits the modulated laser light to the outside, and modulated light entering from the outside. In an optical space transmission device configured to include a receiving unit including a receiving optical system that receives a laser beam and demodulates it to obtain a signal, in an optical space transmission device, a refractive index of light changes from two optical elements according to an applied voltage. The optical devices formed by stacking the respective refraction directions are orthogonal to each other in a plane perpendicular to the optical axis of the laser light.
An optical space transmission device, characterized in that the optical devices are arranged in the optical system such that the refraction directions of the respective optical devices coincide with each other in each of the two axial directions. 2. The optical device has a liquid crystal enclosed between two transparent substrates bonded together with an arbitrary apex angle, and corresponds to a voltage applied between electrodes provided on the transparent substrate. The optical space transmission device according to claim 1, wherein the optical space transmission device comprises a wedge-shaped optical element whose refractive index changes. 3. The optical device has a liquid crystal enclosed between two transparent substrates joined with an arbitrary apex angle, and corresponds to a voltage applied between electrodes provided on the transparent substrate. 2. The optical space transmission device according to claim 1, wherein the two wedge-shaped optical elements whose refractive index changes are constituted by optical members that are surface-bonded by inverting the wedge-shaped apex angle by 180 degrees. 4. A liquid crystal is enclosed between two transparent substrates joined together with an arbitrary apex angle, and the refractive index changes according to the voltage applied between the electrodes provided on the transparent substrate. The optical space transmission device according to claim 1, wherein an optical device configured by a wedge-shaped optical element is used for a transmission optical system of a transmission unit. 5. A liquid crystal is sealed between two transparent substrates bonded together with an arbitrary apex angle, and the refractive index changes in accordance with the voltage applied between the electrodes provided on the transparent substrate. 2. An optical device comprising two wedge-shaped optical elements, each of which is composed of an optical member in which the wedge-shaped apex angle is inverted by 180 degrees and surface-bonded is used in a transmission optical system of a transmission means. Optical space transmission equipment. 6. A liquid crystal is sealed between two transparent substrates joined together with an arbitrary apex angle, and the refractive index changes according to the voltage applied between the electrodes provided on the transparent substrate. The optical space transmission device according to claim 1, wherein the optical device configured by a wedge-shaped optical element is disposed in close contact with the laser light emission lens of the transmission optical system on the side of the spatial transmission path. 7. A liquid crystal is enclosed between two transparent substrates bonded with an arbitrary apex angle, and the refractive index changes in accordance with the voltage applied between the electrodes provided on the transparent substrate. An optical device composed of two wedge-shaped optical elements in which the wedge-shaped apex angle is inverted by 180 degrees and surface-bonded to each other is arranged closely to the space transmission path side of the laser light emitting lens of the transmission optical system. The optical space transmission device according to claim 1, wherein: 8. A liquid crystal is sealed between two transparent substrates joined together with an arbitrary apex angle, and the refractive index changes in accordance with a voltage applied between electrodes provided on the transparent substrate. The optical space transmission device according to claim 1, wherein an optical device configured by a wedge-shaped optical element is used for a receiving optical system of the receiving means. 9. A liquid crystal is sealed between two transparent substrates bonded together with an arbitrary apex angle, and the refractive index changes according to a voltage applied between electrodes provided on the transparent substrate. The optical device comprising an optical member in which two wedge-shaped optical elements are surface-bonded by inverting the wedge-shaped apex angle by 180 degrees is used in a receiving optical system of a receiving means. Optical space transmission equipment. 10. A liquid crystal is enclosed between two transparent substrates joined together with an arbitrary apex angle, and the refractive index changes in accordance with a voltage applied between electrodes provided on the transparent substrate. 2. The optical space transmission device according to claim 1, wherein the optical device configured by a wedge-shaped optical element is disposed in close contact with the light receiving lens of the receiving optical system on the side of the spatial transmission path. 11. A liquid crystal is sealed between two transparent substrates that are bonded together with an arbitrary apex angle, and the refractive index changes in accordance with the voltage applied between the electrodes provided on the transparent substrate. An optical device composed of two wedge-shaped optical elements that are surface-bonded by inverting the wedge-shaped apex angle by 180 ° is arranged closely to the space transmission path side of the receiving lens of the receiving optical system. The optical space transmission device according to claim 1, which is characterized in that: 12. In an optical space transmission device having a transmission optical system and a reception optical system provided in one housing, a liquid crystal is sealed between two transparent substrates bonded with an arbitrary apex angle, and the transparent An optical device including a wedge-shaped optical element whose refractive index changes according to a voltage applied between electrodes provided on a substrate is used for each optical system of the transmission optical system and the reception optical system. The optical space transmission device according to claim 1. 13. An optical space transmission device having a transmission optical system and a reception optical system provided in one housing, wherein a liquid crystal is sealed between two transparent substrates bonded with an arbitrary apex angle, An optical device in which two wedge-shaped optical elements whose refractive index changes according to a voltage applied between electrodes provided on a transparent substrate are composed of optical members which are surface-bonded by inverting the wedge-shaped apex angle by 180 degrees. 2. The optical space transmission device according to claim 1, wherein the optical transmission system is used for each optical system of the transmission optical system and the reception optical system. 14. An optical apex having a transmission optical system and a reception optical system provided in a single housing, each of which has an arbitrary apex angle in close contact with a space transmission path side of an emission lens and a light receiving lens of each optical system. A liquid crystal is enclosed between two transparent substrates bonded together, and an optical device composed of a wedge-shaped optical element whose refractive index changes according to a voltage applied between electrodes provided on the transparent substrate is transmitted. The optical space transmission device according to claim 1, wherein the optical space transmission device is provided in each of an optical system and an optical system of the receiving optical system. 15. An optical system having a transmission optical system and a reception optical system provided in a single housing is closely contacted with a space transmission path side of an output lens and a light receiving lens of each optical system and has an arbitrary apex angle. The liquid crystal is sealed between the two transparent substrates bonded together,
An optical device composed of two wedge-shaped optical elements whose refractive index changes in response to a voltage applied between electrodes provided on the transparent substrate, which are surface-bonded by inverting the wedge-shaped apex angle by 180 degrees. The optical space transmission device according to claim 1, wherein the optical transmission system is provided in each of the optical systems of the transmission optical system and the reception optical system. 16. In an optical space transmission device that shares an emission lens of a transmission optical system and an incidence lens of a reception optical system, liquid crystal is sealed between two transparent substrates that are bonded together with an arbitrary apex angle. 2. The optical space transmission according to claim 1, wherein the optical device comprises a wedge-shaped optical element whose refractive index changes according to a voltage applied between electrodes provided on the transparent substrate. apparatus. 17. In an optical space transmission device that shares an emission lens of a transmission optical system and an incidence lens of a reception optical system, liquid crystal is sealed between two transparent substrates bonded with an arbitrary apex angle. And two wedge-shaped optical elements whose refractive index changes according to the voltage applied between the electrodes provided on the transparent substrate are formed by optical members that are surface-bonded by inverting the wedge-shaped apex angle by 180 degrees. Characterized by using an optical device,
The optical space transmission device according to claim 1. 18. An optical space transmission device having a lens configuration that shares an emission lens of a transmission optical system and an incidence lens of a reception optical system, and has an arbitrary apex angle in close contact with the space transmission path side of the shared lens. A liquid crystal is enclosed between two transparent substrates bonded together, and an optical device composed of wedge-shaped optical elements whose refractive index changes according to a voltage applied between electrodes provided on the transparent substrate is provided. The optical space transmission device according to claim 1, wherein 19. An optical aerial space transmission device having a lens structure in which an exit lens of a transmission optical system and an entrance lens of a reception optical system are shared, and the optical space transmission device has an apex angle in close contact with a space transmission path side of the shared lens. A liquid crystal is sealed between two transparent substrates bonded together, and two wedge-shaped optical elements whose refractive index changes in response to a voltage applied between electrodes provided on the transparent substrate are provided in the wedge-shaped top. The optical space transmission device according to claim 1, further comprising an optical device configured by an optical member which is surface-bonded by inverting an angle of 180 degrees.