JP3463781B2 - Laser distance measuring device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser distance measuring device for measuring a distance by scanning a laser beam emitted from a laser light source with respect to a target.

[0002]

2. Description of the Related Art As a laser distance measuring device of this type,
For example, there is one as shown in FIG. The illustrated laser distance measuring device scans the transmission laser light LT emitted from the laser light source 101 with the rotary polygon mirror 102, and receives the reception laser light LR reflected by the target with the same rotary polygon mirror 102. The received laser light LR received by the rotary polygon mirror 102 is reflected to the rear side of the rotary polygon mirror 102 by the fixed concave mirrors 103, 103 provided on both sides thereof, and the respective reflecting mirrors 10 are reflected.
The light is input to one light receiving unit 106 via the optical recording units 104 and 104 and the optical filters 105 and 105.

Then, the laser distance measuring device measures the distance to the target based on the time difference between the reference light obtained from the transmission laser light LT and the received laser light LR input via the above optical system. Further, the laser distance measuring device scans the transmission laser light LT within a certain plane by rotating the rotary polygon mirror 102 also around a pitch axis P orthogonal to the rotation axis R of itself. I am trying to do it.

[0004]

However, in the conventional laser distance measuring device as described above, the fixed concave mirrors 103 and 103 are provided on both sides of the rotary polygon mirror 102. Therefore, for example, the rotary polygon mirror is used. If an attempt is made to increase the rotation angle of the 102 about the pitch axis P, the rotary polygon mirror 102
There is a problem that a part of the received laser light LR reflected by the laser light may be deviated from the concave mirror 103, which may reduce the amount of light input to the light receiving unit 106 and reduce the measurement accuracy. The problem was to solve such problems.

Although it is conceivable to make the concave mirror 103 large so that the received laser light LR does not come off, in this case, the received laser light LR to the rotary polygon mirror 102 is blocked by the large-sized concave mirror, and conversely the rotary polygon. As a result, the rotation angle of the mirror 102 about the pitch axis P is limited.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and always obtains the maximum amount of received laser light even when the rotation angle around the pitch axis of the rotary polygon mirror is increased. It is an object of the present invention to provide a laser distance measuring device capable of performing the above.

[0007]

According to a first aspect of the present invention, there is provided a laser distance measuring device for reflecting a transmitted laser beam emitted from a laser light source toward a target and receiving a received laser beam reflected at the target. The rotary polygonal mirror includes a rotary polygonal mirror, a pitching mechanism for rotating the rotary polygonal mirror around a pitch axis orthogonal to its rotation axis, and a concave mirror for reflecting the received laser light reflected by the rotary polygonal mirror to the light receiving optical system side. The mirror and the concave mirror are configured to be integrally rotatable around the pitch axis, the concave mirror is provided in the pitching mechanism as claimed in claim 2, and the curvature for condensing the concave mirror on the pitch axis as claimed in claim 3. And a secondary reflecting mirror for reflecting the received laser beam reflected by the concave mirror to the light receiving optical system side is provided on the pitch axis, and the secondary reflecting mirror is a concave mirror. Is a convex mirror that reflects the received laser light on the pitch axis and is rotatable integrally with the concave mirror, and the received laser light reflected by the secondary reflecting mirror on the pitch axis is directed to the receiving optical system side. A fixed third-order reflecting mirror for reflecting the light is provided, and as claimed in claim 5, both sides of the rotary polygon mirror are
A concave mirror, a secondary reflecting mirror, a tertiary reflecting mirror and a light receiving optical system are arranged respectively, and a light receiving portion to which the received laser light that has passed through each light receiving optical system is input is arranged behind the rotary polygon mirror. The above structure is used as a means for solving the conventional problems.

[0008]

In the laser distance measuring apparatus according to the first aspect of the present invention, since the rotary polygon mirror and the concave mirror which are rotated by the pitching mechanism are integrally rotated about the same pitch axis, the reflection of the rotary polygon mirror. The surface and the light receiving surface of the concave mirror are always coincident with each other, and the received laser light reflected by the rotary polygon mirror does not come off from the concave mirror, and all the received laser light is reflected by the concave mirror and sent to the light receiving optical system side. Therefore, even if the rotation angle of the rotary polygon mirror about the pitch axis is increased, the maximum amount of received laser light is reflected to the light receiving optical system side via the concave mirror.

In the laser distance measuring device according to the second aspect of the present invention, since the concave mirror is provided in the pitching mechanism for rotating the rotary polygon mirror about the pitch axis, the rotary polygon mirror and the concave mirror can be rotated with a simple structure. Will definitely match.

In the laser distance measuring apparatus according to claim 3 of the present invention, the received laser light reflected by the concave mirror which is the primary reflecting mirror that rotates together with the rotary polygon mirror is condensed on the pitch axis, and the received laser light is received. Is reflected to the light receiving optical system side by a secondary reflecting mirror provided on the pitch axis. That is, the received laser light from the rotating concave mirror is sent to the fixed light receiving optical system side without reducing the light amount.

In the laser distance measuring apparatus according to the fourth aspect of the present invention, since the secondary reflecting mirror is a convex mirror, the received laser light reflected by the secondary reflecting mirror becomes a parallel beam, and the secondary reflecting mirror is also provided. Since the lens can be rotated integrally with the concave mirror, the reflecting surface of the concave mirror and the light receiving surface of the secondary reflecting mirror always match, and the received laser light reflected by the concave mirror does not come off from the secondary reflecting mirror. All of the received laser light becomes a parallel beam from the secondary reflecting mirror, is reflected by the fixed tertiary reflecting mirror, and is further sent from the tertiary reflecting mirror to the light receiving optical system side. That is, the received laser light from the rotating concave mirror is always kept on the pitch axis between the rotating secondary reflecting mirror and the fixed tertiary reflecting mirror, and is fixed from the tertiary reflecting mirror without reducing the light quantity. Is sent to the light receiving optical system side.

In the laser distance measuring device according to the fifth aspect of the present invention, the received laser light received by the rotary polygon mirror is reflected by the concave mirrors on both sides of the rotary polygon mirror, and both received laser lights are received by the respective optical systems for receiving light. Finally, the light is input to one light receiving section provided behind the rotary polygon mirror. At this time, a concave mirror and a secondary reflecting mirror which rotate around the pitch axis together with the rotary polygon mirror are provided. Therefore, the received laser light is condensed on the pitch axis without reducing the light quantity, and is always kept on the pitch axis between the rotating secondary reflecting mirror and the fixed tertiary reflecting mirror. It is sent from the secondary reflecting mirror to the fixed light receiving optical system side.

In addition, in the laser distance measuring apparatus according to the fifth aspect, in addition to the function of sending the received laser light between the rotating side and the fixed side as described above, the receiving laser light from the rotary polygon mirror is The concave mirror reflects the light toward the center of the device, which is the rotary polygon mirror side, and then each secondary reflector reflects the light toward the semi-center, and the third reflector reflects the light toward the center again. In order to achieve the above, it is possible to dispose the light receiving optical system that receives the laser light received from the tertiary reflecting mirror near the center of the device.

[0014]

According to the laser distance measuring apparatus of the first aspect of the present invention, the rotary polygon mirror and the concave mirror which are rotated by the pitching mechanism are integrally rotated about the same pitch axis, so that the rotary polygon mirror is rotated. Even if the rotation angle around the pitch axis of is increased, all the received laser light is reflected by the concave mirror and sent to the light receiving optical system side, and the maximum amount of received laser light can be reflected to the light receiving optical system side. In addition, it is possible to realize high measurement accuracy as the scanning range is expanded.

According to the laser distance measuring device of the second aspect of the present invention, the same effect as that of the first aspect can be obtained, and since the concave mirror is provided in the pitching mechanism of the rotary polygon mirror, it is simple. With the structure, the rotation of the rotary polygon mirror and the rotation of the concave mirror can be surely matched with each other, and it is possible to contribute to securing a sufficient light amount, further improving the measurement accuracy, and downsizing and cost reduction of the device.

According to the laser distance measuring device of the third aspect of the present invention, the same effects as those of the first and second aspects can be obtained, and the pitch axis of the received laser beam by the concave mirror which is the primary reflecting mirror. Focus on top, and 2 on the pitch axis
By the secondary reflecting mirror, the received laser light from the rotating concave mirror can be satisfactorily sent to the fixed light receiving optical system side.

According to the laser distance measuring device of the fourth aspect of the present invention, the same effects as those of the first to third aspects can be obtained, and the secondary reflecting mirror of the convex mirror that rotates together with the concave mirror is adopted. This makes it possible to convert all the received laser light from the concave mirror into a parallel beam and send it in a state of maximum light quantity. Also, by adopting a fixed tertiary reflecting mirror on the pitch axis, The receiving laser beam can be always kept on the pitch axis between the rotating secondary reflecting mirror and the fixed tertiary reflecting mirror, and the receiving laser beam can be satisfactorily and reliably transmitted from the rotating side to the fixed side. You can

According to the fifth aspect of the present invention, it is possible to obtain the same effects as those of the first to fourth aspects, and in addition, in an apparatus provided with two paths of the received laser beam behind both sides of the rotary polygon mirror, The received laser light from the rotary polygon mirror is reflected by each concave mirror toward the rotary polygon mirror, that is, toward the center of the device, then by each secondary reflector toward the semi-center, and again by the tertiary reflector toward the center. Since the light is reflected by the light receiving optical system, it is possible to dispose the light receiving optical system that receives the laser light received from the tertiary reflecting mirror near the center of the device, and thus the device can be downsized.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a laser distance measuring device according to the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a laser distance measuring device 1
Is a laser light source 2 which is, for example, a laser diode with a collimator, and a transmission laser light LT emitted as parallel light from the laser light source 2 toward a target (not shown) in the case 11 and a reception laser reflected by the target. A rotary polygon mirror 3 that receives the light LR, a motor 4 that rotates the rotary polygon mirror 3 around a vertical rotation axis R in the drawing, and a rotation polygon mirror 3 that rotates around a pitch axis P orthogonal to the rotation axis R. A pitching mechanism (or nodding mechanism) 5 is provided.

Further, the laser distance measuring device 1 is provided with concave mirrors 6 and 6 which are primary reflecting mirrors for receiving the received laser light LR reflected by the rotary polygonal mirror 3 on both sides of the rotary polygonal mirror 3, and the rotary polygonal surface. On both sides of the rear part of the mirror 3, there are provided a reflecting mirror 7 and an optical filter 8 which form a light receiving optical system, and behind the rotary polygon mirror 3, the received laser light LR which has passed through the respective light receiving optical systems (7, 8). A distance detector 10 having one light receiving unit 9 for receiving the light is included. The concave mirrors 6 and 6 will be described later in 2
The received laser light LR from the rotary polygon mirror 3 is sent to the respective light receiving optical system sides via the second and third reflecting mirrors.

The distance detector 10 includes a rear wall 11 of the case 11.
For example, a photodiode is used for the light receiving unit 9 installed in a, and a part of the transmission laser light LT is received as a reference light by another input unit, and the reference light and the reception laser light LR are received as an electric signal. Then, the distance data is detected based on the time difference between the two signals.

The pitching mechanism 5 includes the bottom portion 1 of the case 11.
1b, a pair of stands 12, 12 provided to face each other, a base 13 rotatably provided between the stands 12, 12, a torquer 14 for rotating the base 13, and a rotation direction of the base 13. Equipped with a resolver 15 for switching,
The pitch axis P passing through the center of the rotary polygon mirror 3 and the base 13
The rotary polygon mirror 3 and the motor 4 are mounted in the center of the base 13 so that the center of rotation of the base 13 coincides with the center of rotation.

The concave mirrors 6 and 6 are mounted on the base 13 of the pitching mechanism 5 so as to face each other with the rotary polygon mirror 3 in between. Therefore, each concave mirror 6 rotates integrally with the base 13 and the rotary polygon mirror 3. Each concave mirror 6 has an inner surface in the shape of a parabola having a curvature for focusing on the pitch axis P, and is arranged so that the pitch axis P passes through the apex of the parabolic surface.

Further, between the rotary polygon mirror 3 and the concave mirrors 6 and 6, the secondary reflecting mirror 2 facing the concave mirrors 6 and 6 is provided.
2 and 22 are provided, and the tertiary reflecting mirrors 23 and 23 facing the secondary reflecting mirrors 22 and 22 are provided at the vertex positions of the paraboloids of the concave mirrors 6 and 6. That is, the secondary and tertiary reflecting mirrors 22 and 23 are provided on the pitch axis P.

The secondary reflecting mirror 22 is a convex mirror, and reflects the received laser light LR from the concave mirror 6 into a parallel beam and reflects it on the pitch axis P, that is, toward the tertiary reflecting mirror 23. 2 each
The secondary reflecting mirror 22 is attached to the base 13 of the pitching mechanism 5 or the like, and rotates integrally with the rotary polygon mirror 3 and each concave mirror 6.

On the other hand, the tertiary reflecting mirror 23 is a secondary reflecting mirror 22.
The laser beam LR received from the laser beam is reflected toward the reflecting mirror 7 of the light receiving optical system, and as shown in FIG. 3, inside the circular hole 6a formed at the apex position of the parabolic surface of the concave mirror 6. And is attached to the bottom portion 11b of the case 11 or the like. Therefore, the tertiary reflecting mirror 23 is in a fixed state while the concave mirror 6 and the secondary reflecting mirror 22 rotate.

In the laser distance measuring device 1 having the above structure, for example, when the distance to the target on the ground is measured obliquely from above, first, the transmission laser light LT emitted from the laser light source 2 in parallel is rotated by the rotating polygon mirror. It is reflected by the reflection area on the lower side of 3 and is sent toward the target. At this time, the transmission laser beam LT moves in the rotation direction by the rotation of the rotary polygon mirror 3 around the rotation axis R by the motor 4 and the operation of the torquer 14 of the pitching mechanism 5 causes the rotary polygon mirror 3 to rotate.
Since it also moves around the pitch axis P that is orthogonal to the rotation direction of, the scanning on the substantially fan-shaped plane is performed.

Next, as shown in FIG. 2, the laser light reflected by the target is received by the reflection area on the upper side of the rotary polygon mirror 3 as the received laser light LR, and the concave mirrors on both sides (one side in FIG. 2). (Omitted) 6 is reflected. At this time, in the laser distance measuring device 1, since the rotary polygon mirror 3 and each concave mirror 6 which are rotated by the pitching mechanism 5 are integrally rotated around the same pitch axis P, the rotary polygon mirror 3 has a reflecting surface. The light receiving surface of the concave mirror 6 always coincides with the received laser light LR reflected by the rotary polygon mirror 3 and does not deviate from the concave mirror 6, and all the received laser light LR is reflected by the concave mirror 6.

Therefore, in the laser distance measuring apparatus 1, even if the rotation angle of the rotary polygon mirror 3 about the pitch axis P is increased, the maximum amount of light is transmitted to the light receiving optical system (7, 8) side via the concave mirror 6. The received laser light LR of is transmitted. Further, a pitching mechanism 5 for rotating the rotary polygon mirror 3 around the pitch axis P.
Since the concave mirror 6 is provided in the
The rotations of are sure to coincide.

Further, the laser distance measuring device 1 collects the received laser light LR on the pitch axis P by each concave mirror 6 and uses the secondary reflection mirror 22 arranged on the pitch axis P for the received laser light LR. The receiving laser beam LR is collimated by the secondary reflecting mirror 22 to be reflected on the pitch axis P, and the receiving laser beam LR is reflected by the tertiary reflecting mirror 23 to the receiving optical system (7, 8). send. The received laser light LR that has passed through each light receiving optical system is received by one light receiving unit 9 of the distance detector 10.
Entered in.

At this time, in the laser distance measuring apparatus 1, since the secondary reflecting mirror 22 and the concave mirror 6 rotate integrally as in the relationship between the rotary polygon mirror 3 and the concave mirror 6 described above, the concave mirror 6 Of the receiving laser beam LR reflected by the concave mirror 6 always coincides with the light receiving surface of the secondary reflecting mirror 22.
Does not deviate from the secondary reflecting mirror 22, and all the received laser light LR is sent from the secondary reflecting mirror 22 to the tertiary reflecting mirror 23. In addition, the received laser light LR from the rotating concave mirror 6
Is always kept on the pitch axis P between the rotating secondary reflecting mirror 22 and the fixed tertiary reflecting mirror 23. That is, the reception laser light LR is satisfactorily transmitted from the rotation side to the fixed side.

As described above, in the laser distance measuring device 1 of the above embodiment, the concave mirror 6 that rotates together with the rotary polygonal mirror 3 receives all the received laser light LR from the rotary polygonal mirror 3 and also performs the primary reflection. In the secondary reflecting mirror 22 that rotates together with the concave mirror 6 that is a mirror, all the received laser light LR from the concave mirror 6 is received, so the received laser light LR
Is sent to the light-receiving optical system side with the maximum amount of light as it is, whereby high measurement accuracy can be obtained.

Further, the laser distance measuring apparatus 1 of the above embodiment
As described above, the concave mirror 6, the secondary reflecting mirror 22, the tertiary reflecting mirror 23, and the light receiving optical system (7, 8) are provided on both sides of the rotary polygon mirror 3.
By arranging each of them, and arranging the light receiving portion 9 to which the received laser light LR having passed through each of the light receiving optical systems is input behind the rotary polygon mirror 3, a system having two paths of the received laser light LR is provided. Originally, it is possible to secure a sufficient amount of light or a sufficient amount of light in a small device. In such a device, in the laser distance measuring device 1,
The received laser light LR from the rotary polygon mirror 3 is reflected by each concave mirror 5 toward the rotary polygon mirror side, that is, toward the center of the apparatus, and then by each secondary reflecting mirror 22 toward the semi-center side. Two
Since the light is reflected again toward the center at 3, the light receiving optical system (7, 8) for receiving the received laser beam LR from the tertiary reflecting mirror 23 is arranged closer to the center of the device, and the size of the device can be further reduced. Has been realized.

[Brief description of drawings]

FIG. 1 is a perspective explanatory view showing an embodiment of a laser distance measuring device according to the present invention.

FIG. 2 is a plan view illustrating paths of transmission laser light and reception laser light.

FIG. 3 is a front view showing a concave mirror and a tertiary reflecting mirror shown in FIG.

FIG. 4 is a perspective view showing a conventional laser distance measuring device.

[Explanation of symbols]

1 Laser distance measuring device 2 laser light source 3 rotating polygon mirror 5 Pitching mechanism 6 concave mirror 7 Light receiving optical system reflector 8 Optical filter of light receiving optical system 9 Light receiving part 22 Secondary mirror 23 3rd reflector LR received laser light LT transmission laser light P pitch axis Rotating axis of R rotary polygon mirror

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01B 11/00-11/30 G01C 3/00-3/32 G01S 7/48-7/50 G01S 17/00-17 / 88 G02B 26/08-26/10

Claims (5)

(57) [Claims] 1. A rotary polygonal mirror for reflecting a transmission laser beam emitted from a laser light source toward a target and receiving a reception laser beam reflected by the target, and the rotary polygonal mirror around a pitch axis orthogonal to its rotation axis. It is equipped with a pitching mechanism that rotates and a concave mirror that reflects the received laser light reflected by the rotary polygon mirror to the light receiving optical system side, and the rotary polygon mirror and the concave mirror can be integrally rotated around the pitch axis. And laser distance measuring device. 2. The laser distance measuring device according to claim 1, wherein the concave mirror is provided in the pitching mechanism. 3. The concave mirror has a curvature for focusing on the pitch axis, and a secondary reflecting mirror for reflecting the received laser light reflected by the concave mirror to the light receiving optical system side is provided on the pitch axis. The laser distance measuring device according to claim 2, wherein 4. The secondary reflecting mirror is a convex mirror that reflects the received laser light from the concave mirror on the pitch axis and is rotatable integrally with the concave mirror, and the secondary reflecting mirror is on the pitch axis. 4. The laser distance measuring device according to claim 3, further comprising a fixed tertiary reflecting mirror that reflects the reflected received laser light to the light receiving optical system side. 5. A concave mirror, a secondary reflecting mirror, a tertiary reflecting mirror and a light receiving optical system are arranged on both sides of the rotary polygon mirror, respectively.
5. The laser distance measuring device according to claim 4, further comprising a light receiving section arranged behind the rotary polygon mirror to which the received laser light having passed through each light receiving optical system is input.