JP2939413B2 - Target reflective object detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of irradiating a polarized irradiation light beam from a main body toward a target reflection object, receiving the reflected light beam reflected by the target reflection object at the main body, and applying the reflected light to the target reflection object. The present invention relates to a target reflection object detection device for detection.

[0002]

2. Description of the Related Art In the field of civil engineering and construction, a laser rotary irradiation device for rotating and scanning a laser beam in a horizontal plane has been used to determine a height standard. Nowadays,
2. Description of the Related Art Visible semiconductor lasers have been put into practical use, and laser rotary irradiation apparatuses using the semiconductor lasers have appeared. However, the output of the semiconductor laser is limited in terms of ensuring the safety of workers, and therefore, the work of setting the height and measuring the work that requires the visual confirmation of the reflection of the laser light beam requires a relatively short working distance. Limited. There has been proposed a laser rotary irradiation device configured to reciprocate to increase the working distance. For example, in Japanese Patent Application No. 5-155608 (Japanese Patent Application Laid-Open No. 7-12569), a reflected light from a specific reflecting object disposed at a predetermined position by a laser beam emitted from a laser rotary irradiation device is used. , The position is detected, and the laser beam is reciprocally scanned on the specific reflection object. In order to reliably identify the object as a target reflecting object, the emitted light is polarized, and the emitted light and the reflected light have different polarization directions. This is because a non-target reflecting object such as a glass surface has a property of reflecting in a state where the polarization direction is preserved, and thus is distinguished from the object.

[0003]

Problems to be Solved by the Invention Japanese Patent Application No. 5-1 mentioned above.
In the laser rotary irradiation device disclosed in Japanese Patent No. 55608, reflected light is detected by detecting means corresponding to a polarized reflected light beam from a target reflecting object. However, in order to completely separate and detect the emitted light and the reflected light, the means for changing the polarization direction in the target reflecting object and the detecting means must be composed of a material in an ideal state and adjusted in an ideal state. Actually, the reflected light from the non-target object is detected, though slightly. Therefore, when the laser light from the laser rotary irradiation device has a glossy member which is a non-target object at a short distance from the main body, and furthermore, the laser light is perpendicularly reflected on the reflection surface of the glossy member similar to the target reflection object and has strong reflection. When the light enters the main body detection section, a detection signal of a long-distance intensity appears, which is recognized as a target reflection object, and a reciprocating operation, that is, a scanning operation may be performed at an incorrect position.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the conventional object reflection object detecting apparatus, and has been made in consideration of the above-mentioned problems. It is an object of the present invention to provide a target reflection object detection device capable of reliably identifying a reflected light beam from a reflection object.

[0005]

According to the present invention, a polarized light beam is radiated from a main body toward a target reflecting object, and a polarized reflected light beam whose polarization direction is changed and reflected by the target reflecting object is received by the main body. An object reflection object detection device for detecting an object reflection object, wherein the main unit controls a direction of irradiation of a polarized irradiation light beam, a first detection unit for detecting a polarized reflected light beam from the object reflection object, A second detecting means for detecting a polarized light beam different from the polarized reflected light beam from the reflecting object, and comparing the output of the first detecting means with the output of the second detecting means, the polarized reflected light beam is reflected by the object reflected object; An object reflection object detection device, characterized in that whether or not it is a light beam is identified and control is performed so that the polarized irradiation light beam is reciprocally scanned with respect to the object reflection object. The present invention is also directed to irradiating a polarized irradiation light beam from the main body portion toward the target reflective object, receiving the polarized reflected light beam whose polarization direction has been changed by the target reflective object and reflected by the main body portion, In the object reflection object detection device for detecting the object, the main body section detects first and second polarized light beams different from the reflected and reflected light beam from the object reflection object. Detecting means, comparing means for comparing the output of the first detecting means with the output of the second detecting means,
Control means for controlling the polarized irradiation light beam to reciprocally scan with respect to the target reflection object based on an output of the comparison means.

[0006]

The polarized light beam is irradiated from the main body toward the target reflecting object, and the reflected light beam reflected by the target reflecting object is detected by the first detecting means and the second detecting means of the main body. The first light receiving unit receives only the polarized reflected light beam from the specific reflecting object, and the second light receiving unit receives the reflected light beam other than the polarized reflected light beam from the target reflecting object. By comparing the two detection outputs, it is determined whether the polarized reflected light beam is a polarized reflected light beam from the target reflective object or a polarized reflected light beam from the non-target reflective object.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a laser rotary irradiation apparatus including a target reflecting object according to an embodiment of the present invention.
The laser rotary irradiation device 1 includes a main body 10 and a reflecting section 100.
Consists of The main body 10 includes a fixed part 12 and a rotating part 50 rotatably supported by the fixed part 12. The fixing unit 12 includes a laser emitting unit 14 and a detecting unit 16. The laser light emitting section 14 includes a collimator lens 20, an inclination correcting section 22, and a λ / 4 birefringent member 24 sequentially arranged on an optical axis 18 of a laser light source 17. The laser light source 17 uses a semiconductor laser that emits a laser beam of substantially linear polarization. When the optical axis 18 of the laser light source 17 is shifted from the vertical direction, the tilt correcting unit 22 corrects the vertical direction and emits the corrected light. The λ / 4 birefringent member 24 converts the incident linearly polarized laser beam into circularly polarized light and emits it. The detection unit 16 includes a perforated mirror 32 having an opening 30 at a portion where the optical axis 18 passes, a polarization beam splitter 36 disposed on a reflection optical axis 34 of the perforated mirror 32, a condenser lens 38, It has one photoelectric detector 40, a condenser lens 41 arranged on the reflection optical axis 39 of the polarizing beam splitter 36, and a second photoelectric detector 42.
Immediately before each of the first photoelectric detector 40 and the second photoelectric detector 42, a pinhole plate 40 ″ in which pinholes 40 ′, 42 ′ are arranged at the focal positions of the condenser lenses 38, 41 on the optical axis, respectively. , 42 '' are placed to eliminate unwanted stray light or noise light. Polarizing beam splitter 36
Transmits polarized light from the target reflective object and reflects polarized light from the non-target reflective object.

[0008] The fixed section 12 further has a control section 44. The control unit 44 includes a first detector 40 and a second detector 4
4 and a driving unit 4 for controlling the rotational driving of the rotating unit 50
6 are connected. The operation of the control unit 44 will be described later. The rotating unit 50 driven by the driving unit 46 includes
A pentaprism 52 swings or rotates around the vertical optical axis 18. The pentaprism 52 rotates or swings a circularly polarized laser beam incident on the bottom surface from the λ / 4 birefringent member 24 in a horizontal plane. Reflector 1
Reference numeral 00 denotes, as shown in FIGS. 2 and 3, a substrate 106 on which a reflector 108 and a birefringent member 110 for providing a phase difference of λ / 4 are attached. The reflecting plate 108 is a retroreflective member, in which a plurality of minute corner cubes or spherical reflectors are arranged. The one shown in FIG. 2 has a reflection function on the entire surface, and the one shown in FIG. 3 has reflection functions on both left and right sides. When a circularly polarized laser beam enters the reflecting section 100, it is converted into linearly polarized light by the birefringent member 110, reflected by the reflector 108, again incident on the birefringent member 110 and converted into circularly polarized light in the opposite direction, Re-enter the prism 52.

Next, the operation of the laser rotary irradiation device 1 having the above configuration will be described. It is assumed that the direction of the laser light source 17 is set so that the linearly polarized plane to be emitted is in a plane including the optical axis 18 and the reflected optical axis 34. This linearly polarized laser light beam is converted into circularly polarized light by the λ / 4 birefringent member 24,
Irradiate 0. In the reflection unit 100, the light is converted into linearly polarized light by the λ / 4 birefringent member 110,
And is returned to circularly polarized light again by the λ / 4 birefringent member 110 and enters the pentaprism 52.
However, the phase of the circularly polarized light returned by the reflection unit 100 is a circularly polarized light having a phase shift of a half wavelength and a reverse rotation with respect to the circularly polarized light incident on the λ / 4 birefringent member 110. The rotation direction of the circularly polarized light of the reflected light beam from the asymmetrical reflecting object does not change. Therefore, the circularly polarized laser beam returned to the pentaprism 52 is returned to linearly polarized light having a plane of polarization on the same plane as the plane of linearly polarized light emitted from the laser light source 17 by the λ / 4 birefringent member 24. The polarization beam splitter 36 transmits a polarization component in a plane including the optical axis 18 and the reflection optical axis 34 and reflects a polarization component in a plane perpendicular to the plane. The portion is transmitted through the polarization beam splitter 36 and enters the first photoelectric detector. As shown in FIG. 4, the output of the first photoelectric detector 40 becomes A, and the output of the second photoelectric detector 42 becomes B. The controller 44 calculates the difference between the peaks of these two outputs, and if this is equal to or greater than a predetermined value, the pentaprism 5
It is determined that 0 points in the direction of the predetermined reflection unit 100.

When the circularly polarized laser beam is reflected by something other than the reflecting section 100, the reflected laser beam is a circularly polarized beam incident on the reflecting object and has the same direction as the circularly polarized beam.
The light passes through the birefringent member 24 and is converted into linearly polarized light having a polarization plane orthogonal to the linear polarization plane emitted from the laser light source 17. Therefore, most of the laser beam reflected by the polarization beam splitter 36 and reflected by a component other than the reflection unit 100 enters the second detector, for example, as shown in FIG. Output of A '
And the output of the second photoelectric detector 42 is B ′. These are mainly noise components, and the control unit 44 calculates the difference between the peaks of these two outputs. If the difference between the peaks is equal to or smaller than a predetermined value, it is determined that the object is not a target reflection object. In the above-described embodiment, the laser light source 17 has been described as being oriented such that the emitted linearly polarized plane is in the plane including the optical axis 18 and the reflected optical axis 34. When the direction of the laser light source 17 is rotated by 90 °, the reflected laser beam from the reflecting unit 100 is reflected by the polarization beam splitter 36 and is incident on the second detector, and the laser beam reflected by other than the incident unit 100 is reflected. Is incident on the first detector, and it can be determined whether or not it is a light beam from the target reflecting object in the same manner as described above.

For example, when the detecting unit 16 detects the target reflecting object, the control unit 44 controls the rotation of the pentaprism 52 so as to continue the reciprocating movement at that position. In the above embodiment, the reflecting portion is irradiated with the circularly polarized laser beam, but the linear laser beam may be irradiated by the reflecting portion. Incidentally, the polarization beam splitter may be constituted by a dichroic mirror, or a half mirror,
A polarization filter may be provided between the detection units 40 and 42 in different directions. A target reflection object detection device according to another embodiment of the present invention is shown in FIG. 6, but the same components as those shown in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted. A condenser lens 20 is provided between the perforated mirror 30 and the polarizing beam splitter 36.
0 is disposed, and the condenser lens 38 in FIG.
41 has been removed. This embodiment has the advantage of having only one condenser lens. FIG. 7 shows a target reflection object detection device according to still another embodiment of the present invention. Components common to those shown in FIG. 6 are denoted by the same reference numerals, and description thereof is omitted. Perforated mirror 3
A pinhole plate 300 ″ having a pinhole 300 ′ on the optical axis is placed between 0 and the polarizing beam splitter 36 to eliminate unnecessary stray light, that is, noise light. FIG.
Are removed. This embodiment has the advantage that there is only one pinhole plate.

[0012]

According to the object reflection object detection apparatus of the present invention, the reflected light beam from the specific reflection object and the reflection light beam from the other non-object reflection object optically similar to the specific reflection object can be reliably identified. The detection distance is lengthened even when using a polarized light beam such as laser light with limited output to ensure the safety of workers by reciprocally scanning the light beam on or near the target reflective object. Is possible.

[Brief description of the drawings]

FIG. 1 is a structural explanatory view of a laser rotary irradiation device including a target reflection object detection device according to an embodiment of the present invention.

FIG. 2 is a front view of a reflection unit of the laser rotary irradiation device shown in FIG.

FIG. 3 is a front view of a reflecting portion of another configuration of the laser rotary irradiation device shown in FIG.

FIG. 4 is a graph showing an output of a photoelectric detection unit when the laser beam shown in FIG. 1 is reflected by a reflection unit.

FIG. 5 is a graph showing an output of a photoelectric detection unit when the laser beam shown in FIG. 1 is reflected by something other than the reflection unit.

FIG. 6 is a structural explanatory view of a laser rotary irradiation device including a target reflection object detection device according to another embodiment of the present invention.

FIG. 7 is a structural explanatory view of a laser rotary irradiation device including a target reflection object detection device according to still another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laser rotation irradiation apparatus 10 Main body part 10 12 Fixed part 14 Laser light emitting part 16 Detecting part 17 Laser light source 18 Optical axis 20 Collimator lens 22 Inclination correction part 24 λ / 4 birefringent member 30 Opening 32 Perforated mirror 36 Polarization beam splitter 38 Condenser lens 40 First photoelectric detector 40 'Pinhole 40' 'Pinhole plate 41 Condenser lens 42 Second photoelectric detector 42' Pinhole 42 '' Pinhole plate 44 Control unit 46 Control unit 50 Rotating unit 52 Pentaprism REFERENCE SIGNS LIST 100 Reflecting portion 100 106 Substrate 108 Reflecting plate 110 Birefringent member 200 Condenser lens 300 'Pinhole 300' 'Pinhole plate

Continuing from the front page (72) Inventor Hiroyuki Nishizawa 75-1, Hasunumacho, Itabashi-ku, Tokyo Topcon Corporation (72) Inventor Kenichiro Yoshino 75-1, Hasunumacho, Itabashi-ku Tokyo, Japan Topcon Corporation (56) Reference Document JP-A-5-197422 (JP, A) JP-A-5-322560 (JP, A) JP-A-4-47211 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01C 5/00-5/06 G01B 11/00-11/30 102 G01C 15/00-15/14 G01C 3/00-3/32 G01C 1/00-1/14

Claims (6)

(57) [Claims] 1. A main body portion irradiates a polarized irradiation light beam toward a target reflective object, and receives a polarized reflected light beam whose polarization direction has been changed by the target reflective object and is reflected by the main body portion. In the object reflection object detection device for detecting the object, the main unit controls the irradiation direction of the polarized irradiation light beam, first detection means for detecting the polarized reflected light beam from the object reflected object, A second detecting means for detecting a polarized light flux different from the polarized reflected light flux, and comparing the output of the first detecting means and the output of the second detecting means, whether the polarized reflected light flux is a polarized reflected light flux from the target reflecting object; Whether the object is reflected or not,
An object reflection object detection device, which performs control so as to reciprocally scan a body . 2. The target object detecting apparatus according to claim 1, wherein the polarized light irradiation light beam is circularly polarized light. 3. An object reflection object detecting apparatus according to claim 1, wherein said polarized light irradiation light beam is linearly polarized light. 4. A polarized light irradiating beam is irradiated from the main body toward the target reflective object, and the polarized reflected light flux whose polarization direction has been changed and reflected by the target reflective object is received by the main body, and the target reflective object is received. In the object reflection object detection device for detecting the object, the main body section detects first and second detection means for detecting a polarized reflected light beam from the object reflected object, and a second detecting means for detecting a polarized light beam different from the polarized reflected light beam from the object reflected object. and detecting means, and comparing means for comparing the outputs of the second detecting means of the first detecting means, the subject the polarized irradiation light beam on the basis of an output of the comparing means
Control means for controlling a reciprocating scan of the reflective object. 5. The object reflection object detecting apparatus according to claim 1, wherein the polarized light beam is circularly polarized light. 6. The target object detecting apparatus according to claim 1, wherein the polarized light beam is linearly polarized light.