JP2956058B2 - Optical space transmission equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in the following order.

A Industrial application fields B Outline of the invention C Conventional technology (Fig. 14) D Problems to be solved by the invention (Fig. 14) E Means for solving the problems (Fig. 1) F function ( (FIG. 1) G embodiment (FIGS. 1 to 13) (G1) First embodiment (FIGS. 1 to 6) (G2) Second embodiment (FIG. 7) (G3) Third embodiment (FIGS. 8 to 11) (G4) Fourth embodiment (FIG. 12) (G5) Fifth embodiment (FIG. 13) (G6) Other embodiments H BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical space transmission device, and is suitable for application to, for example, a bidirectional optical space transmission device.

SUMMARY OF THE INVENTION The present invention relates to a space optical transmission device, in which the overall shape is reduced by displacing the optical path of the light beam emitted from the light source, and the light beam is reliably transmitted even when the distance to the transmission target is large. Can be adjusted.

C Conventional Technology Conventionally, in this type of optical space transmission apparatus, a proposal has been made in which the irradiation position of a light beam is detected on the transmission device side and the irradiation position of the light beam is adjusted based on the detection result. (Japanese Patent Application Nos. 63-134087 and 63-13
No. 4088).

That is, also in FIG. 14, reference numeral 1 denotes a bidirectional optical space transmission device as a whole, in which a lens holding member 2 is disposed in a housing (not shown), and the lens holding member 2 rotates in the horizontal and vertical directions. It is made to move.

In the cylinder of the lens holding member 2, a laser light source 3 for emitting a light beam modulated by a predetermined information signal is arranged at a predetermined position close to a light receiving element (not shown). A large-diameter lens 10 is arranged in front of the laser light source 3.

Thus, the light beam LA1 emitted from the laser light source 3
Is converted into a parallel light beam through the lens 10 and transmitted to a transmission target.

On the other hand, a television camera 11 is arranged above the lens holding member 2, and a collimating scope 13 is arranged in front of the television camera 11 and the lens 10.

In the collimator scope 13, a half mirror 141 is disposed on the optical path of the light beam LA1, and the half mirror 141
After the light beam LA1 is separated at 4, the light beam LA1 is guided to the television camera 11 in parallel with the optical axis L of the light beam LA1.

That is, the collimator scope 13 is configured such that the reflected light LA2 of the half mirror 14 passes through the half mirror 15 held with high parallelism with respect to the half mirror 14, and is guided to the corner cubic prism 16.

Accordingly, the reflected light LA
After being folded back in parallel, 2 is reflected by the half mirror 15 and enters the television camera 11 via the lens 17 in parallel with the light beam LA1.

Thus, based on the reflected light LA3 of the corner tube prism 16 incident on the television camera 11, the laser light source 3
Image can be observed.

Further, the collimating scope 13 is provided with a window 20 in front of the television camera 11, so that the transmission target side can be observed in addition to the image of the laser light source 3.

Therefore, in the television camera 11, the reflected light LA2 is folded back by the corner tube prism 16, so that
Reflected light LA3 as if emitted from the irradiation position of light beam LA1
Can be obtained, whereby the light beam of the laser light source 3 can be obtained.
The same image as when it is arranged at the irradiation position of LA1 can be observed.

Further, the collimator scope 13 is provided with shutters 21 and 22 composed of liquid crystal optical elements, and alternately opens and closes the shutters 21 and 22 so as to alternately capture the image of the laser light source 3 and the image on the transmission target side. ing.

Thus, based on the video signal output from the vision camera 11, the irradiation position of the light beam LA1 on the transmission target can be detected, and by rotating the lens holding member 2 based on the detection result, the light beam LA1 can be detected. The irradiation position can be set as a transmission target.

D Problems to be Solved by the Invention By the way, in the lens holding member 2, since optical components such as the lens 10 must be held with high accuracy,
The weight is inevitably heavy.

Therefore, when the irradiation position is adjusted by rotating the lens holding member 2, there is a problem that the configuration for rotating the lens holding member 2 becomes large, and the spectral space transmission device 1 becomes large.

Furthermore, when the distance to the transmission target is large,
Even if the lens holding member 2 is rotated by a small angle, the light beam
Since the irradiation position of LA1 greatly changes, when the lens holding member 2 is rotated to adjust the irradiation position, there is a problem that the irradiation position cannot be adjusted with high accuracy.

When this type of space optical transmission device 1 is actually installed on the roof of a building or the like, the space optical transmission device 1 vibrates and the light beam LA1
Irradiation direction may vibrate.

Therefore, after the space optical transmission device 1 is installed, it is necessary to always correct the irradiation direction of the light beam LA1.

However, when the irradiation direction is corrected by rotating the lens holding member 2 in this manner, the irradiation direction cannot be corrected at a high speed because the lens holding member 2 is a heavy object.
In practice, when the distance to the transmission target is large, there is a problem that the irradiation position of the light beam LA1 cannot be adjusted with respect to the vibration of the optical space transmission device.

The present invention has been made in view of the above points, and aims to propose a small-sized optical space transmission device that can reliably adjust the irradiation position of a light beam even when the distance to a transmission target is large. Things.

Means for Solving E Problem In order to solve such a problem, according to the present invention, a light source 3 for emitting a light beam LA1 modulated with a predetermined information signal is provided.
And optical path displacing means 31 and 32 for displacing the optical path of the light beam LA1 in parallel, driving means 34 and 35 for rotatably driving the optical path displacing means 31 and 32, respectively, and a light beam emitted from the optical path displacing means Transmission optical system 3 for sending LA1 to a predetermined transmission target
0, and the irradiation position of the light beam LA1 is controlled by controlling the rotation angle of the optical path displacement means 31, 32.

F action The optical path of the light beam LA1 emitted from the light source 3 is moved in parallel by changing the angles of the optical path displacement means 31 and 32, and is incident on the transmission optical system 30.
The irradiation position of the light beam LA1 can be finely adjusted.

G Example Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

(G1) First Embodiment In FIG. 1, in which parts corresponding to those in FIG. 14 are denoted by the same reference numerals, reference numeral 30 denotes a bidirectional optical space transmission device as a whole, between the laser light source 3 and the lens 10. , Optically parallel flat plate
Insert 31 and 32.

The laser light source 3 emits a light beam LA1 having a wavelength of 830 [nm], while the optical parallel flat plates 31 and 32 emit the light beam LA1.
For a wavelength of 830 [nm], a parallel flat plate having a thickness of 1 [mm] using optical glass of the symbol BK7 having a refractive index of 1.510 is used.

Further, the optically parallel plane plates 31 and 32 are respectively indicated by arrows a
As shown by b and b, it is driven by the driving devices 34 and 35 composed of galvanoschiana, so that it can rotate around the vertical axis and the horizontal axis passing through the center of the optical parallel plane plates 31 and 32. It has been made like that.

Therefore, as shown in FIG. 2, in the light beam LA1,
When the optically parallel plane plate 31 or 32 is arranged perpendicular to the optical axis of the light beam AL1, as shown by a straight line L1, the laser light source 3
Passes through an optical path that goes straight from.

On the other hand, the optical parallel plane plate 31 or 32
When placed at an angle to the optical axis of LA1, the light beam LA1 is straight
As shown by L2, the laser light source 3 passes through an optical path as if the laser light source 3 was moved in parallel in accordance with the inclination of the optically parallel plane plate 31 or 32 (that is, represented by symbol 3A).

Therefore, as shown in FIG.
By adjusting the inclination of 32, the symbol 3C
As shown by, the position of the laser light source 3 can be equivalently moved by the distance D by displacing the optical path of the light beam in accordance with the inclination of the optical parallel plane plate 31 or 32.

As a result, the light beam LA1 passing through the center O of the lens 10
Can be inclined by a predetermined angle α, and the emission direction of the light beam LA1 can be finely adjusted.

Specifically, as shown in FIG.
Or 32 is arranged at an angle θ _{I with} respect to the optical axis K of the light beam LA1, and if the refractive indices of the optical parallel plane plates 31 and 32 are n and the thickness is d, the following equation is obtained. Holds the relationship, for example, the angle θ if you set the _I to 40 degrees, equivalently distance the position of the laser light source 3 D = 0.282 [m
m].

Incidentally, instead of rotating the optical parallel plane plates 31 and 32 to move the position of the laser light source 3 equivalently, a method of directly moving the laser light source 3 in parallel is also conceivable.

However, in this type of two-way optical space transmission device 30, a light receiving element for receiving a light beam transmitted from the transmission target side in the vicinity of the laser light source 3 and the laser light source 3 transmit the light beam LA1 in the optical axis direction. In order to adjust the irradiation position by directly moving the laser light source 3, it is necessary to provide an adjustment mechanism or the like for adjusting the light beam emitted from the lens 10 to a parallel light beam. Inevitably, the configuration becomes complicated.

Thus, as shown in FIG. 5, the distance from the lens 10 to the laser light source 3 is set to 250 [mm] (that is, the lens 1).
The focal length of 0 is set to 250 [mm] and the laser light source 3 is left on the focal plane.) When irradiating the transmission target 1 km away with the light beam LA1, the laser light source 3 Is moved by the distance D = 0.282 [mm], the light beam L
The injection direction of A1 is At the angle α represented by.

Accordingly, when the optical parallel plane plate 31 or 32 is rotated by 40 degrees, the irradiation position of the light beam LA1 can be moved by the same distance as when the conventional lens holding member 2 is rotated by 0.065 degrees, whereby The adjustment accuracy of the irradiation position can be remarkably improved as compared with the related art.

Thus, on the transmission target side, The irradiation position of the light beam LA1 can be moved by the distance E represented by.

In this embodiment, the optical parallel plane plates 31 and 32 are set so that they can be rotated by ± 50 degrees with respect to the optical axis of the light beam LA1, respectively. Irradiation position up to 1.5
[M] can be moved at a time.

Thus, as shown in FIG. 6, even if the optically parallel flat plates 31 and 32 are largely turned, the irradiation position can be moved by a very small distance, thereby ensuring that the light can be reliably transmitted even when the distance to the transmission target is large. The irradiation position of the beam LA1 can be adjusted.

In addition, the light irradiation position of the light beam LA1 can be adjusted with high accuracy by a simple configuration that is lighter than the lens holding member 2 and simply rotates the optical parallel flat plates 31 and 32. (In this case, the driving devices 34 and 35) for adjusting the size of the optical parallel flat plates 31 and 32 can be driven at a high speed.

Therefore, the overall configuration is reduced in size, and
Even when the light beam itself vibrates, the irradiation position of the light beam LA1 that follows the vibration can be corrected.

Incidentally, in this embodiment, the optical parallel plane plates 31 and 32 are arranged close to the laser light source 3, whereby the optical parallel plane plates 31 and 32 having a small shape are used. Even when the optical parallel plane plates 31 and 32 are inclined,
Only the light beam LA1 transmitted through the optically parallel flat plates 31 and 32 enters the lens 10.

Further, optically parallel plane plates 31 and 32, driving devices 34 and 35
Can be downsized, the optically parallel plane plate 31 and
The drive devices 34 and 35 are sealed together with the laser light source 3 and the lens 10 to reduce the influence of wind and the like.

Thus, in this embodiment, the laser light source 3 constitutes a light source that emits a light beam LA1 modulated by a predetermined information signal, and the optical parallel plane plates 31 and 32, and the driving devices 34 and 35 form an optical path of the light beam LA1. The lens 10 constitutes a transmission optical system that sends out a light beam LA1 emitted from the optical path displacement optical system to a transmission target, while constituting an optical path displacement optical system for displacement.

According to the above configuration, the optical parallel plane plates 31 and 32 interposed between the laser light source 3 and the lens 10 are rotated to displace the optical path of the light beam LA1, so that the overall shape is small and high. The irradiation position of the beam LA1 can be adjusted accurately and at high speed.

(G2) Second Embodiment In FIG. 7, in which parts corresponding to those in FIG. 1 are assigned the same reference numerals, reference numeral 40 denotes an optical space transmission device, and a single optical parallel plane plate 41 is used. The irradiation position of the light beam LA1 can be adjusted.

That is, the optical parallel flat plate 41 is held by the holder 45 so as to be able to rotate around a vertical axis passing through the center of the optical parallel flat plate 41 while being held by the holder 42. It has been made like that.

On the other hand, the holder 45 is provided so that it can rotate around a horizontal axis passing through the center of the optical parallel flat plate 41 as a rotation center.
47 is to be held.

As a result, the optical parallel plane plate 41 is
And 47, driven by motors 48 and 49 attached to
As shown by arrows c and d, the rotation is made in the horizontal and vertical directions.

Accordingly, by driving the motors 48 and 49 as needed, the optical parallel plate 41 can be inclined by a predetermined angle in the horizontal and vertical directions to displace the optical path of the light beam.

Thus, in this embodiment, the optical parallel plate 4
1. The holders 42, 45, 47 and the motors 48, 49 constitute an optical path displacement optical system for displacing the optical path of the light beam LA1.

According to the configuration of FIG. 7, even if only one optical parallel plane plate 41 is used, the same effect as that of the first embodiment can be obtained by tilting the optical parallel plane plate 41 in the horizontal and vertical directions. Can be obtained.

(G3) Third Embodiment In the optical space transmission apparatus 50 shown in FIG. 8, a light beam is produced by changing the inclination of mirrors 51 and 52 instead of an optically parallel plane plate.
Adjust the irradiation position of LA1.

That is, the laser light source 3 is arranged on the focal point of the lens 54, whereby the light beam emitted from the laser light source 3 is converted into a parallel light beam and outputted from the mirror 51.

The mirror 51 is rotated by a driving device 34 with a horizontal axis passing through the center of the mirror 51 as a center axis, and reflects the light beam LA1 converted into parallel rays to the mirror 52.

Thus, the light beam LA1 whose incident angle has changed in the horizontal direction according to the amount of rotation of the mirror 51 is incident on the mirror 52.

On the other hand, the mirror 52 is a driving device similar to the mirror 51.
The mirror 52 is rotated so that the mirror 52 emits a light beam whose emission angle changes in the vertical direction in accordance with the amount of rotation of the mirror 52.

The lens 55 receives the light beam reflected by the mirror 52, and is arranged such that the focal point of the lens 10 is located on the focal plane of the lens 55.

As a result, the light beam LA1 whose angle is tilted in the horizontal direction and the vertical direction via the mirrors 51 and 52 respectively becomes the lens 55.
After being focused on the focal plane of the lens 10 by the lens 10, the light is converted into a parallel light by the lens 10 and emitted.

Therefore, as shown in FIG.
When the lens 55 is tilted only by this angle, the light beam incident on the lens 55 is tilted by the angle 2β, and the focal position of the light beam by the lens 55 moves from point P1 to point P2.

Thereby, the light beam condensed at the point P2 indicated by the symbol L4 can be emitted by displacing by the angle γ with respect to the emission direction of the light beam condensed at the point P1 indicated by the signal L3.
The irradiation position of the light beam LA1 can be adjusted according to the amount of rotation of the 52.

In this case, as shown in FIG. 10, the focal length of the lens 55
f ₂ , the focal length of the lens 10 is F, and the distance from the point P1 to the point P2 is ΔP, Which gives the light beam LA1 the following equation: Can be displaced by an angle γ represented by

Accordingly, assuming that the distance to the transmission target is H, in the transmission target, the irradiation position of the light beam LA1 can be displaced by the distance E represented by the following equation: E = H · tanγ (7).

Thus, in this embodiment, the focal length of lens 55
If f _{2 is set} to 20 [mm], the focal length F of the lens 10 is set to 250 [mm], and the distance H to the transmission target is set to 100 [m], the angle β of the mirror 51 or 52 changes by 1 degree ( From equation (6), the emission angle of the light beam LA1 is changed by 0.16 minutes, whereby the irradiation position of the light beam LA1 is moved by 279 [mm] from equation (7).

Therefore, as shown in FIG. 11, the irradiation position of the light beam LA1 can be moved in accordance with the amount of rotation of the mirrors 51 and 52, whereby the irradiation position of the light beam LA1 can be adjusted with high accuracy. it can.

When the optical path of the light beam LA1 is changed using an optical parallel plate as in the first and second embodiments, the optical parallel plate is inserted on the optical path of the light beam. In addition, aberrations such as astigmatism, spherical aberration, distortion, and field curvature occur in the optical system of the entire optical space transmission apparatus, and the quality of the transmitted light beam may be degraded accordingly.

Further, when an optical parallel plate is used, there is a disadvantage that the adjustment accuracy of the irradiation position is increased more than necessary, and the circuit amount of the spectroscopic parallel plate is increased.

However, when the optical path is displaced by using the mirrors 51 and 52 as in this embodiment, it is possible to effectively avoid the occurrence of aberration and to obtain practically sufficient adjustment accuracy.

Further, as described above, if the light beam is once converted into a parallel light beam to displace the optical path, the arrangement position of the laser light source 3 with respect to the lens 10 can be freely selected as necessary. The entire spectral space transmission device can be reduced in size.

Thus, in this embodiment, mirrors 51, 52, lens 5
4, 55 and the driving devices 34 and 35 constitute an optical path displacement optical system for displacing the optical path of the light beam LA1.

According to the configuration shown in FIG. 8, since the mirrors 51 and 52 are rotated to displace the optical path of the light beam LA1, the occurrence of aberration is effectively avoided, and the irradiation position of the beam is adjusted with sufficient adjustment accuracy for practical use. Can be adjusted, thus the light beam with high accuracy and high speed
The optical space transmission device 50 that can adjust the irradiation position of the LA1 can be obtained.

(G4) Fourth Embodiment As shown in FIG. 12, in this embodiment, the light beam LA1 emitted from the space optical transmission device 60 by one mirror 59 is used.
Adjust the irradiation position of.

That is, the light beam LA1 emitted from the laser light source 3
Is reflected by a mirror 59 which can be rotated in the horizontal and vertical directions via a lens 54, and then guided to a lens 10 via a lens 55.

Thus, in this embodiment, the holders 42, 45, 47,
Motors 48 and 49, lenses 54 and 55, and mirror 59
An optical path displacement optical system for displacing the optical path of LA1 is configured.

According to the configuration of FIG. 12, even if only one mirror 59 is used, the same effect as in the third embodiment can be obtained by tilting the mirror 59 in the horizontal direction and the vertical direction.

(G5) Fifth Embodiment As shown in FIG. 13, in this embodiment, a mirror 59 is mounted on a spherical bearing 62 used in a joystick or the like.
, Thereby moving the arm 63 to rotate the mirror 59 in the horizontal and vertical directions.

According to the configuration of FIG. 13, the mirror 59 can be supported by the spherical seat bearing 62, and the same effect as in the fourth embodiment can be obtained.

(G6) Other Embodiments In the first and second embodiments described above, the symbol BK
Although the case where the optical parallel plane plate is configured using the optical glass of 7 has been described, the material of the glass is not limited to this, and for example, for a light beam having a frequency of 830 (nm) as necessary,
SF11 glass with a refractive index of 1.76 312, refractive index 1.83109
Glass of the symbol LaSF9, and various materials such as synthetic sapphire having a refractive index of 1.7594 can be widely applied.

In this case, for example, when the optical parallel plane plate having a thickness of 1 mm is made of glass having a refractive index of 1.83109 and the symbol LaSF9, when the optical parallel plane plate is inclined by 50 degrees, θ _{R is obtained} from the equation (1). = 24.731 degrees, and the laser light source 3 can be equivalently moved by a distance D = 0.4698 [mm].

Therefore, the irradiation position of the light beam can be moved 1880 [mm] up, down, left and right with respect to the transmission target 1 [km] away.

Further, in the first and second embodiments, the case where the irradiation position of the light beam is adjusted by using the optically parallel plane plate has been described. The adjustment may be made using an optical component such as a relay lens instead of the face plate.

Further, in the first and second embodiments, the case where the irradiation position of the light beam is adjusted by interposing the optical parallel plane plate on the optical path of the light beam has been described. In addition to the plane-parallel plate, for example, an optical component such as a lens may be interposed to correct various aberrations caused by the plane-parallel plate.

Further, in the third, fourth and fifth embodiments, the case where the irradiation position of the light beam is adjusted by tilting the mirror has been described. However, the present invention is not limited to the mirror and may use, for example, a prism. .

Further, in the above-described embodiment, the case where the optical parallel flat plate or the mirror is rotated by the driving device using the galvano-skyana has been described, but the driving device is not limited to this.
For example, various driving means such as a motor can be widely applied.

Further, in the above embodiment, the case where the light beam LA1 is transmitted from the laser light source is described. However, the present invention is not limited to this, and can be widely applied to a case where a light source such as a light emitting diode is used.

Further, in the above-described embodiment, the case where the present invention is applied to the two-way optical space transmission device has been described. can do.

H Effect of the Invention As described above, according to the present invention, a light beam emitted from a light source is made incident on an optical path displacing means, and the angle of the optical path displacing means with respect to the optical path of the light beam is changed and emitted from the optical path displacing means. By displacing the optical path of the light beam in parallel and making it incident on the transmission optical system, the irradiation position of the light beam can be finely adjusted, and thus the overall size is small and the distance to the transmission target is large. Even in such a case, it is possible to obtain an optical space transmission device capable of surely adjusting the irradiation position of the light beam.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an optical space transmission apparatus according to an embodiment of the present invention, FIG. 2, FIG. 3, FIG. 4, and FIG. FIG. 7 is a characteristic curve diagram showing the relationship between the amount of rotation of the optically parallel flat plate and the irradiation position.
FIG. 8 is a perspective view showing the third embodiment, FIGS. 9 and 10 are schematic diagrams for explaining the operation thereof, and FIG. 11 is a diagram showing the amount of rotation of the mirror and irradiation. FIG. 12 is a characteristic curve diagram showing the relationship with the position, FIG. 12 is a perspective view showing the fourth embodiment, and FIG.
FIG. 14 is a perspective view showing a fifth embodiment, and FIG. 14 is a schematic diagram showing a conventional optical space transmission apparatus. 1, 30, 40, 50, 60 ... optical space transmission device, 3 ... laser light source, 10, 17, 54, 55 ... lens, 31, 32, 41 ... optical parallel plane plate, 51, 52, 59 …… Mirror.

──────────────────────────────────────────────────の Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H04B 10/10-10/105

Claims (1)

(57) [Claims] 1. A light source for emitting a light beam modulated by a predetermined information signal, and a transparent flat plate having a plane of incidence and a plane of emission parallel to each other, and the light incident obliquely with respect to the plane of incidence. The optical path of the beam is displaced in parallel while passing through the flat plate, an optical path displacing means for emitting the light from the emission surface, a driving means for rotatably driving the optical path displacing means, and a light emitted from the optical path displacing means. A transmission optical system for transmitting the light beam to a predetermined transmission target, and controlling the rotation angle of the optical path displacing means to control the irradiation position of the light beam. .