Surveying device

Abstract

The present invention comprises: a ranging unit having a light-emitting element (31) that emits a ranging beam and a light-receiving element that receives a reflected ranging beam from an object being measured; rotary deflecting units (15, 24) that radiate the ranging beam; a perpendicular-rotation drive unit (13) that rotates the rotary deflecting units perpendicularly via a hollow perpendicular-rotation shaft (11); a bracket unit (5) on which the rotary deflecting units are provided; a horizontal-rotation drive unit (8) that rotates the bracket unit horizontally; and an arithmetic-operation control unit (17) that performs arithmetic operations on the distance to the object being measured, on the basis of results of reception of the reflected ranging beam at the light-receiving element. The rotary deflecting units are configured: so as to include a cast-beam deflecting unit that is formed in the center part of the rotary deflecting units and deflects the ranging beam at right angles, and a received-beam deflecting unit that is formed outside the center part and deflects the reflected ranging beam at right angles in the opposite direction from that of the light-emitting element; so that a through-hole (23) which interconnects with the hollow section of the perpendicular rotation shaft and which is parallel to the optical axis of the ranging beam is formed in the received-beam deflecting unit; and so that the cast-beam deflecting unit is arranged so that a portion thereof is fitted into the through-hole.

Description

surveying equipment

[0001] The present invention relates to a surveying instrument capable of acquiring three-dimensional coordinates of a measurement object.

[0002] Surveying instruments such as laser scanners and total stations have optical distance measuring devices that detect the distance to an object to be measured using prism distance measurement, which uses a retroreflective prism as the object to be measured, or non-prism distance measurement, which does not use a reflective prism.

[0003] In conventional optical distance measuring devices, the distance measuring light emitting section that emits the distance measuring light and the distance measuring light receiving section that receives the reflected distance measuring light are incorporated into a single optical system, and a deflecting optical member is required to make the optical axis of the distance measuring light and the optical axis of the reflected distance measuring light coaxial, which leads to an increase in the size of the optical system and the entire surveying device.

[0004] US Patent Application Publication No. 2022 / 0373685

[0005] The present invention provides a surveying instrument that allows for miniaturization of the optical system and the entire instrument.

[0006] The present invention includes a distance measuring unit having a light emitting element that emits distance measuring light and a light receiving element that receives the reflected distance measuring light from a measurement object, a rotary deflector that emits the distance measuring light, a vertical rotation drive unit that rotates the rotary deflector in a vertical direction via a hollow vertical rotation shaft, a base unit on which the rotary deflector is provided, a horizontal rotation drive unit that rotates the base unit in a horizontal direction, and an arithmetic control unit that calculates the distance to the measurement object based on the light receiving element receiving the reflected distance measuring light. and a section, wherein the rotary deflection section has a light projecting deflection section formed in the center of the rotary deflection section and deflecting the distance measuring light at a right angle, and a light receiving deflection section formed outside the center and deflecting the reflected distance measuring light at a right angle in the opposite direction to the light emitting element, and the light receiving deflection section is formed with a through hole that communicates with the hollow section of the vertical rotation shaft and is parallel to the optical axis of the distance measuring light, and the light projecting deflection section is arranged so that a part of it fits into the through hole.

[0007] The present invention also relates to a surveying instrument in which the light receiving deflection unit is a cylinder having a reflective surface formed at its end for reflecting the optical axis of the distance measuring light at a right angle, and the light projecting deflection unit is a light projecting mirror, and the light projecting mirror is fitted into the through hole and has a cylindrical portion for making the distance measuring light that has passed through the vertical rotation axis incident at a right angle, a rod mirror having a reflective surface for reflecting the distance measuring light that has passed through the cylindrical portion, and a cylindrical lens integrated with the rod mirror.

[0008] The present invention also relates to a surveying instrument in which the cylindrical lens has a recess with a curvature equal to that of the cylindrical portion and a flat portion onto which the distance measuring light reflected by the reflecting surface is incident at a right angle, and the cylindrical portion and the recess are configured to fit tightly together without any gaps.

[0009] The present invention also relates to a surveying instrument in which a chamfered portion having an inclination equivalent to the inclination of the reflecting surface of the light receiving deflection portion is formed at the base end of the cylindrical lens, and the reflecting surface and the chamfered portion are configured to come into contact with each other.

[0010] The present invention also relates to a surveying instrument in which the cylindrical lens has a cylindrical shape with the same diameter as the cylindrical portion, and the flat portion has a circular shape with the same diameter as the cylindrical portion.

[0011] The present invention also relates to a surveying instrument in which the reflecting surface of the light receiving deflection section is an off-axis paraboloid or a free-form surface.

[0012] Furthermore, the present invention relates to a surveying instrument that further comprises a window portion that covers the periphery of the light-projecting mirror and is fixedly provided on the support portion, the window portion having a cylindrical or conical shape that is coincident with or parallel to the axis of the vertical rotation axis, and is configured so that any one of the entrance surface of the cylindrical portion onto which the distance-measuring light is incident, the reflecting surface, and the exit surface of the cylindrical lens onto which the distance-measuring light reflected by the reflecting surface is incident at a right angle is a cylindrical surface.

[0013] According to the present invention, a distance measuring device includes a light emitting element that emits distance measuring light and a light receiving element that receives the reflected distance measuring light from an object to be measured, a rotary deflector that irradiates the distance measuring light, a vertical rotation drive unit that rotates the rotary deflector in a vertical direction via a hollow vertical rotation shaft, a base unit on which the rotary deflector is provided, a horizontal rotation drive unit that rotates the base unit in a horizontal direction, and a calculation control unit that calculates the distance to the object to be measured based on the light receiving result of the reflected distance measuring light received by the light receiving element, and the rotary deflector is The device has a light-projecting deflection section formed in the center and deflecting the distance-measuring light at a right angle, and a light-receiving deflection section formed outside the center and deflecting the reflected distance-measuring light at a right angle in the opposite direction to the light-emitting element, and the light-receiving deflection section is configured so that a portion of it is fitted into the through-hole, which communicates with the hollow section of the vertical rotation shaft and is parallel to the optical axis of the distance-measuring light.Therefore, there is no need to incorporate the light-emitting element and the light-receiving element into a single optical system, which makes it possible to reduce the size of the optical system and the overall device.

[0014] FIG. 1 is a front cross-sectional view showing a surveying instrument according to a first embodiment. FIG. 2 is an enlarged view of the main parts showing the light-projecting unit and the light-receiving unit according to the first embodiment. FIGS. 3(A) and 3(B) are explanatory diagrams illustrating the rotary deflection unit according to the first embodiment. FIGS. 4(A) to 4(C) are explanatory diagrams illustrating the light-projecting mirror according to the first embodiment. FIGS. 5(A) to 5(C) are explanatory diagrams illustrating the light-projecting mirror according to the second embodiment. FIG. 6(A) is a side view showing the relationship between the light-projecting mirror and the window according to the third embodiment, and FIG. 6(B) is a perspective view showing the relationship between the light-projecting mirror and the window according to the third embodiment. FIGS. 7(A) to 7(C) are explanatory diagrams illustrating the light-projecting mirror according to the third embodiment.

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0016] First, a surveying instrument according to a first embodiment of the present invention will be described with reference to FIGS.

[0017] The surveying instrument 1 is, for example, a laser scanner, and is composed of a leveling unit 2 attached to a tripod (not shown), and a surveying instrument main body 3 attached to the leveling unit 2 .

[0018] The leveling unit 2 has a leveling screw 10, which is used to level the surveying instrument main body 3 horizontally.

[0019] The surveying instrument main body 3 is equipped with (contains) a fixed section 4, a base section 5, a horizontal rotation shaft 6, a horizontal rotation bearing 7, a horizontal rotation motor 8 as a horizontal rotation drive section, a horizontal angle encoder 9 as a horizontal angle detector, a vertical rotation shaft 11, a vertical rotation bearing 12, a vertical rotation motor 13 as a vertical rotation drive section, a vertical angle encoder 14 as a vertical angle detector, a light-receiving mirror 15, an operation panel 16 that serves both as an operation section and a display section, an arithmetic and control section 17, a memory section 18, a light-projecting section 19, a light-receiving section 21, etc. The arithmetic and control section 17 may be a CPU specialized for this instrument or a general-purpose CPU.

[0020] The horizontal rotation bearing 7 is fixed to the fixed part 4. The horizontal rotation shaft 6 has a vertical axis 6a, and the horizontal rotation shaft 6 is rotatably supported by the horizontal rotation bearing 7. In addition, the base part 5 is supported by the horizontal rotation shaft 6, and the base part 5 rotates integrally with the horizontal rotation shaft 6 in the horizontal direction.

[0021] The horizontal rotation motor 8 is provided between the horizontal rotation bearing 7 and the base frame 5, and the horizontal rotation motor 8 is controlled by the arithmetic and control unit 17. The arithmetic and control unit 17 causes the horizontal rotation motor 8 to rotate the base frame 5 about the axis 6a.

[0022] The relative rotation angle of the base part 5 with respect to the fixed part 4 is detected by the horizontal angle encoder 9. A detection signal from the horizontal angle encoder 9 is input to the calculation control part 17, which calculates horizontal angle data. The calculation control part 17 performs feedback control on the horizontal rotation motor 8 based on the horizontal angle data.

[0023] The base 5 is provided with the vertical rotation shaft 11 having a horizontal axis 11a. The vertical rotation shaft 11 is rotatable via the vertical rotation bearing 12. The intersection of the axis 6a and the axis 11a is the emission position of the distance measuring light, and is the origin of the coordinate system of the surveying device main body 3.

[0024] A recess 22 is formed in the base frame 5. The vertical rotation shaft 11 is hollow, and one end thereof extends into the recess 22. The light-receiving mirror 15 is fixed to the one end of the vertical rotation shaft 11, and the light-receiving mirror 15 is housed in the recess 22.

[0025] The light-receiving mirror 15 is a cylindrical body made of glass or a metal material such as aluminum, with the end cut to form a reflective surface. The reflective surface is flat and configured to deflect the incident light-receiving optical axis 43 (described below) at a right angle. For example, the light-receiving mirror 15 is a 45° rod mirror that deflects the light-receiving optical axis 43 at a right angle. A cylindrical through-hole 23 is formed in the center of the light-receiving mirror 15, communicating with the hollow portion of the vertical rotation shaft 11 and concentric with the vertical rotation shaft 11. One end of the through-hole 23 opens into the recess 22 via the reflective surface of the light-receiving mirror 15, with the lower end of the opening protruding laterally a predetermined distance beyond the upper end of the opening.

[0026] A part of a light projecting mirror 24 is fitted and adhered to the through hole 23. The reflecting surface of the light projecting mirror 24 protrudes from the through hole 23 into the recess 22 and is configured to reflect a distance measuring optical axis 25 (described later) incident horizontally at a right angle.

[0027] 3(A), 3(B), and 4(A) to 4(C), the light projecting mirror 24 is composed of a rod mirror 26 and a cylindrical lens 27 that is attached to and integrated with the rod mirror 26 so as to be in close contact with the rod mirror 26. In the following description, the side that protrudes into the recess 22 is referred to as the tip side, and the side opposite the recess 22 is referred to as the base side.

[0028] The rod mirror 26 has a cylindrical portion 26a made of a transparent material such as glass, and a reflective surface 26b formed by cutting the end face of the cylindrical portion 26a at a 45° angle and depositing a metal film or a dielectric multilayer film on the cut surface. In other words, the rod mirror 26 is a 45° rod mirror. The cylindrical portion 26a is fitted into the through-hole 23, and the reflective surface 26b protrudes from the through-hole 23 and is configured to deflect the ranging optical axis 25, which is horizontally incident, at a right angle while aligned with the axis of the rod mirror 26.

[0029] The cylindrical lens 27 is a plano-concave cylindrical lens composed of a flat surface and a concave curved surface, and is attached to the rod mirror 26 so as to face the reflecting surface 26b. At this time, the distance measurement optical axis 25 deflected at a right angle by the reflecting surface 26b is made to be perpendicularly incident on the rectangular flat surface portion 27a of the cylindrical lens 27 at an incident angle of 0°. The recess 27b of the cylindrical lens 27 has a semicircular cross section, and the curvature of the recess 27b matches the curvature of the circumferential surface of the rod mirror 26 (the cylindrical portion 26a). The length of the cylindrical lens 27 in the width direction is longer than the diameter of the cylindrical portion 26a.

[0030] The rod mirror 26 and the cylindrical lens 27 are integrated without any gaps, and half or approximately half of the circumferential surface of the rod mirror 26 is covered with the cylindrical lens 27 .

[0031] Therefore, the distance measurement optical axis 25 does not deflect at the boundary between the rod mirror 26 and the cylindrical lens 27. Also, all of the light passing through the cylindrical portion 26a can be made incident on the flat portion 27a.

[0032] Furthermore, a chamfered portion 27c is formed at the base end of the cylindrical lens 27 so as to be chamfered downward and inclined from the base end side to the tip end side, and the inclination angle of the chamfered portion 27c matches the inclination angle of the light-receiving mirror 15. When the rod mirror 26 is installed in the through-hole 23, as shown in Fig. 2, the light-receiving mirror 15 and the chamfered portion 27c come into contact, and the distance-measuring light axis 25 deflected by the light-projecting mirror 24 matches the light-receiving light axis 43 incident on the light-receiving mirror 15, and further the axis of the cylindrical portion 26a matches the distance-measuring light axis 25. In other words, the chamfered portion 27c acts as a positioning mechanism for the light-projecting mirror 24.

[0033] The vertical angle encoder 14 is provided at the other end of the vertical rotation shaft 11. The light projecting unit 19 is provided at a position separated from the other end of the vertical rotation shaft 11. The light projecting unit 19 is made up of a distance measuring light emitting unit 28 and a tracking light emitting unit 29.

[0034] The distance measurement light emitting unit 28 has the distance measurement optical axis 25. The distance measurement light emitting unit 28 also has, in order from the light emitting side, a light emitting element 31 provided on the distance measurement optical axis 25, for example, a laser diode (LD) that emits near-infrared light of a predetermined wavelength as distance measurement light 32, a light projecting lens 33, a dichroic mirror 34, and the light projecting mirror 24 provided on the transmission optical axis of the dichroic mirror 34.

[0035] The dichroic mirror 34 has optical properties that allow the distance measurement light 32 to pass through and reflect the tracking light 35. The dichroic mirror 34 is provided on a common optical path of the distance measurement light 32 and the tracking light 35 (at the intersection of the distance measurement optical axis 25 and a tracking optical axis 36 (described later)). The dichroic mirror 34 deflects (reflects) the tracking optical axis 36 so that the tracking optical axis 36 coincides with the distance measurement optical axis 25 that has passed through the dichroic mirror 34. Therefore, the distance measurement light 32 and the tracking light 35 are incident on the light projecting mirror 24 coaxially and are reflected by the light projecting mirror 24 at a right angle.

[0036] The distance measurement optical axis 25 is deflected while passing through the dichroic mirror 34, and the deflected distance measurement optical axis 25 coincides with the axis 11a. Therefore, the tracking optical axis 36 reflected by the dichroic mirror 34 also coincides with the axis 11a.

[0037] The tracking light emitting unit 29 has the tracking optical axis 36. The tracking light emitting unit 29 also has, in order from the light emitting side, a tracking light emitting element 37 provided on the tracking optical axis 36, for example, a laser diode (LD) that emits near-infrared light having a wavelength different from that of the distance measuring light 32 as the tracking light 35, a tracking light projection lens 38, the dichroic mirror 34, and the light projecting mirror 24 provided on the reflected optical axis of the dichroic mirror 34.

[0038] Also, on the axis 6a, at a position facing the light-receiving mirror 15, there is provided a window 39 made of a transparent material such as glass, which rotates integrally with the light-receiving mirror 15. The window 39 is inclined at a predetermined angle with respect to the axis 6a. The light-receiving mirror 15 constitutes a light-receiving deflection unit, and the light-projecting mirror 24 constitutes a light-projecting deflection unit. Furthermore, the light-receiving deflection unit and the light-projecting deflection unit constitute a rotary deflection unit that is rotated integrally in the vertical direction by the vertical rotary motor 13 via the vertical rotation shaft 11.

[0039] The vertical rotation motor 13 is provided on the vertical rotation shaft 11, and the vertical rotation motor 13 is controlled by the arithmetic and control unit 17. The arithmetic and control unit 17 rotates the vertical rotation shaft 11 using the vertical rotation motor 13, and the light receiving mirror 15 and the light projecting mirror 24 rotate around the axis 11a.

[0040] The rotation angle of the light-receiving mirror 15 is detected by the vertical angle encoder 14, and the detection signal is input to the calculation control unit 17. The calculation control unit 17 calculates vertical angle data of the light-receiving mirror 15 based on the detection signal, and performs feedback control on the vertical rotation motor 13 based on the vertical angle data.

[0041] The horizontal angle data, vertical angle data, and measurement results calculated by the calculation control unit 17 are stored in the memory unit 18. The memory unit 18 may be a magnetic storage device such as an HDD, an optical storage device such as a CD or DVD, a semiconductor storage device such as a memory card, or a USB memory. The memory unit 18 may be detachable from the base unit 5, or may be capable of transmitting data to an external storage device or external data processing device via a communication device (not shown).

[0042] The storage unit 18 stores various programs such as a sequence program for controlling the distance measurement operation, an arithmetic program for calculating distance by the distance measurement operation, an arithmetic program for calculating an angle based on horizontal angle data and vertical angle data, a program for calculating the three-dimensional coordinates of a desired measurement point based on the distance and angle, a tracking program for tracking a target, etc. Furthermore, various processes are performed by the arithmetic control unit 17 executing the various programs.

[0043] The operation panel 16 is, for example, a touch panel, and serves as both an operation section for issuing distance measurement instructions and changing measurement conditions, such as the measurement point interval, and a display section for displaying distance measurement results, images, and the like.

[0044] Next, the light receiving section 21 will be described with reference to Fig. 2. In this embodiment, a target having retroreflectivity, such as a prism, is used as the object to be measured.

[0045] The light receiving section 21 has a distance measuring light receiving section 41 and a tracking light receiving section 42. The distance measuring light emitting section 28 and the distance measuring light receiving section 41 form a distance measuring section, and the tracking light emitting section 29 and the tracking light receiving section 42 form a tracking section.

[0046] The distance measurement light receiving unit 41 has the light receiving optical axis 43. The distance measurement light receiving unit 41 also has, in order from the light receiving side, a light receiving element 44, a light receiving prism 45, and a light receiving lens 46, which are provided on the light receiving optical axis 43.

[0047] The light-receiving prism 45 has a dichroic film 47 as a separation surface. The light-receiving prism 45 is configured to internally reflect at least once the distance-measuring light 32 (reflected distance-measuring light 48) reflected by the object to be measured and the tracking light 35 (reflected tracking light 49) incident coaxially with the reflected distance-measuring light 48. The dichroic film 47 has optical properties that reflect the reflected distance-measuring light 48 and transmit the reflected tracking light 49.

[0048] In this embodiment, the light receiving optical axis 43 and the light receiving optical axis 43 reflected by the light receiving prism 45 and the dichroic film 47 are collectively referred to as the light receiving optical axis 43 .

[0049] The tracking light receiving unit 42 has a tracking light receiving optical axis 51. The tracking light receiving unit 42 also has, in order from the light receiving side, a tracking light receiving element 52, the light receiving prism 45, and the light receiving lens 46, which are provided on the tracking light receiving optical axis 51. In this embodiment, the tracking light receiving optical axis 51 and the tracking light receiving optical axis 51 reflected by the light receiving prism 45 are collectively referred to as the tracking light receiving optical axis 51.

[0050] The tracking light receiving element 52 is a CCD or CMOS sensor that is a collection of pixels, and the position of each pixel can be specified on the tracking light receiving element 52. For example, each pixel has pixel coordinates with the center of the tracking light receiving element 52 as the origin, and the position on the tracking light receiving element 52 is specified by the pixel coordinates.

[0051] The light-projecting unit 19 and the light-receiving unit 21 are controlled by the arithmetic and control unit 17. The pulsed distance-measuring light 32 emitted from the light-emitting element 31 onto the distance-measuring optical axis 25 passes through the light-projecting lens 33 and the dichroic mirror 34, passes through the interior of the vertical rotation shaft 11 and the through-hole 23, and is incident on the base end surface of the cylindrical portion 26a of the rod mirror 26 at an incident angle of 0°.

[0052] The distance measurement light 32 passes through the cylindrical portion 26a along the axis of the cylindrical portion 26a and is reflected at a right angle by the reflecting surface 26b. The distance measurement light 32 reflected by the reflecting surface 26b enters the cylindrical lens 27 through the recess 27b, enters the flat portion 27a at an incident angle of 0°, and is then emitted.

[0053] Since the distance measurement light 32 enters the cylindrical portion 26a at an incident angle of 0° and exits from the flat portion 27a, no deflection occurs in the distance measurement light 32 during incidence and emission. Furthermore, since the cylindrical lens 27 of the rod mirror 26 is integrated without any gaps, no deflection occurs when the distance measurement light 32 passes through the boundary surface between the rod mirror 26 and the cylindrical lens 27.

[0054] The distance measuring light 32 reflected at a right angle by the light projecting mirror 24 passes through the window 39 and is irradiated onto the object to be measured. The light projecting mirror 24 rotates integrally with the light receiving mirror 15 around the axis 11a, so that the distance measuring light 32 rotates (scans) within a plane that is perpendicular to the axis 11a and includes the axis 6a.

[0055] The reflected distance measuring light 48 reflected by the object to be measured passes through the window 39 and enters the light receiving mirror 15 coaxially with the distance measuring light 32. The reflected distance measuring light 48 is also reflected at a right angle by the light receiving mirror 15, is collected by the light receiving lens 46, and enters the light receiving prism 45. In the process of passing through the light receiving prism 45, it is reflected by the dichroic film 47 and is received by the light receiving element 44.

[0056] The light receiving optical axis 43 of the reflected distance measuring light 48 reflected by the light receiving mirror 15 is coaxial with the distance measuring optical axis 25 transmitted through the dichroic mirror 34. That is, the distance measuring optical axis 25 and the light receiving optical axis 43 coincide with the axis center 11a.

[0057] Furthermore, since the window portion 39 is inclined at a predetermined angle with respect to the distance measurement optical axis 25, the distance measurement light 32 reflected by the window portion 39 is prevented from being reflected by the light receiving mirror 15 and received by the light receiving element 44.

[0058] The calculation control unit 17 measures the distance for each pulse of the distance measuring light 32 (Time Of Flight) based on the time difference between the light emission timing of the light emitting element 31 and the light reception timing of the light receiving element 44 (i.e., the round-trip time of the pulsed light) and the speed of light, and calculates the distance to the object to be measured. The light emission timing of the light emitting element 31, i.e., the pulse interval, can be changed via the operation panel 16. Furthermore, the three-dimensional coordinates of the object to be measured can be calculated based on the distance measurement result and the horizontal angle data and vertical angle data obtained by the horizontal angle encoder 9 and the vertical angle encoder 14.

[0059] Furthermore, by rotating the base frame 5 and the light-receiving mirror 15 (the light-projecting mirror 24) at a constant speed while emitting the distance-measuring light 32 at a predetermined pulse interval, the vertical rotation of the light-receiving mirror 15 and the horizontal rotation of the base frame 5 cooperate to perform two-dimensional scanning with the distance-measuring light 32. Furthermore, by detecting the vertical angle and horizontal angle for each pulse of light using the vertical angle encoder 14 and the horizontal angle encoder 9, vertical angle data and horizontal angle data can be obtained. From the vertical angle data, horizontal angle data, and distance data, the three-dimensional coordinates of the object to be measured and three-dimensional point cloud data corresponding to the object to be measured can be obtained.

[0060] In parallel with the distance measurement operation, the tracking light 35, which is near-infrared light of a different wavelength from the distance measurement light 32 emitted from the tracking light-emitting element 37, is slightly diverged by the tracking projection lens 38 and then deflected by the dichroic mirror 34 so as to be coaxial with the distance measurement light 32. The tracking light 35 passes through the interior of the vertical rotation shaft 11 and the through-hole 23, and is incident on the cylindrical portion 26a of the rod mirror 26 at a right angle with an incident angle of 0°. The tracking light 35 passes through the cylindrical portion 26a and is incident on the reflecting surface 26b. The tracking light 35 reflected at a right angle by the reflecting surface 26b is incident on the cylindrical lens 27 via the recess 27b, is incident on the flat portion 27a at an incident angle of 0°, and is emitted therefrom. The tracking light 35 passes through the window 39 and is irradiated onto the object to be measured.

[0061] The reflected tracking light 49, which is irradiated onto the measurement object coaxially with the distance measuring light 32 and reflected coaxially by the measurement object, passes through the window 39, is reflected at a right angle by the light receiving mirror 15, and is incident on the light receiving prism 45 via the light receiving lens 46. The reflected tracking light 49 incident on the light receiving prism 45 is separated from the reflected distance measuring light 48 by the dichroic film 47 while passing through the light receiving prism 45, passes through the dichroic film 47, and is received by the tracking light receiving element 52. Furthermore, a tracking image (not shown) can be obtained by receiving the reflected tracking light 49 at the tracking light receiving element 52.

[0062] The calculation control unit 17 is configured to calculate the position deviation between the center of the tracking light receiving element 52 and the receiving position of the reflected tracking light 49 relative to the tracking light receiving element 52, and based on the position deviation, drive the horizontal rotation motor 8 and the vertical rotation motor 13 to track the object to be measured.

[0063] As described above, in the first embodiment, the light-projecting unit 19 and the light-receiving unit 21 are arranged on opposite sides of the light-receiving mirror 15. Therefore, it is not necessary to incorporate the light-projecting unit 19 and the light-receiving unit 21 into one optical system, and a deflecting optical member for deflecting the distance-measuring light 32 and the reflected distance-measuring light 48 so that they are coaxial is not required. This makes it possible to reduce the number of parts and to make the optical system and the surveying instrument 1 as a whole more compact.

[0064] Furthermore, the rod mirror 26 and the cylindrical lens 27 constitute the light-projecting mirror 24, and the rod mirror 26 and the cylindrical lens 27 are integrated so that the recess 27b of the cylindrical lens 27 covers the upper half or approximately half of the periphery of the rod mirror 26 without any gaps.

[0065] Therefore, the distance measuring light 32 and the tracking light 35 reflected by the reflecting surface 26b are not deflected by the peripheral surface of the rod mirror 26, and all of the light enters and is emitted from the cylindrical lens 27. Therefore, the effective diameter of the distance measuring light 32 and the tracking light 35 can be expanded to approximately the same as the diameter of the cylindrical portion 26a, and the cylindrical surface size of the rod mirror 26 can be minimized relative to the beam diameter of the distance measuring light 32 and the tracking light 35 that are desired to be emitted.

[0066] Furthermore, the chamfered portion 27c having an inclination equivalent to that of the light-receiving mirror 15 is formed at the base end of the cylindrical lens 27. Therefore, by bringing the chamfered portion 27c into contact with the light-receiving mirror 15, the light-projecting mirror 24 can be automatically positioned, thereby improving workability and reducing work time.

[0067] Furthermore, the vertical rotation shaft 11 is hollow, and the light-receiving mirror 15 is formed with the through-hole 23 that is concentric with the vertical rotation shaft 11 and communicates with the hollow portion, and the light-projecting mirror 24 is provided in the through-hole 23 and has the cylindrical portion 26 a that is concentric with the vertical rotation shaft 11 and the through-hole 23, i.e., concentric with the rotation axis of the light-receiving mirror 15 and rotates integrally therewith.

[0068] Therefore, the distance measurement optical axis 25 incident on the reflecting surface 26b of the light projecting mirror 24 and the light receiving optical axis 43 deflected by the light receiving mirror 15 can be made coaxial, thereby improving measurement accuracy.

[0069] Moreover, since it is only necessary to form the through-hole 23 in the light-receiving mirror 15 and provide the light-projecting mirror 24 in the through-hole 23, the manufacturing is easy and the manufacturing cost can be reduced.

[0070] Next, a second embodiment of the present invention will be described with reference to Figures 5(A) to 5(C). In Figures 5(A) to 5(C), the same components as those in Figures 4(A) to 4(C) are designated by the same reference numerals, and their description will be omitted.

[0071] In the second embodiment, the cylindrical lens 53 has a cylindrical shape with a circular flat portion 53 a , and the diameter of the flat portion 53 a is the same as or approximately the same as the cylindrical portion 26 a of the rod mirror 26 .

[0072] 5C, the recess 53b of the cylindrical lens 53 has a semicircular cross section with a curvature equal to that of the circumferential surface of the cylindrical portion 26a. Therefore, the rod mirror 26 and the cylindrical lens 53 are tightly attached and integrated with each other via the inner surface of the recess 53b and the circumferential surface of the cylindrical portion 26a. The other configurations are the same as those of the first embodiment.

[0073] In the second embodiment, the cylindrical lens 53 has a cylindrical shape with a diameter equal to that of the cylindrical portion 26 a of the rod mirror 26, and the rod mirror 26 and the cylindrical lens 53 are tightly integrated with each other through the recess 53 b without any gaps, thereby constituting a light-projecting mirror 54.

[0074] Therefore, the distance measuring light 32 and the tracking light 35 reflected by the reflecting surface 26b pass through the cylindrical lens 53 having the same diameter as the cylindrical portion 26a and are emitted from the flat portion 53a.

[0075] Also in the second embodiment, the total amount of light of the distance measuring light 32 and the tracking light 35 reflected by the reflecting surface 26b is incident on the cylindrical lens 53 without being deflected by the peripheral surface of the rod mirror 26 and is emitted from the flat portion 53a. Therefore, the effective diameter of the distance measuring light 32 and the tracking light 35 can be expanded to approximately the same as the diameter of the cylindrical portion 26a, and the cylindrical surface size of the rod mirror 26 can be minimized with respect to the beam diameter of the distance measuring light 32 and the tracking light 35 that are desired to be emitted.

[0076] Furthermore, since the incident area of ​​the reflected distance measuring light 48 on the flat surface portion 53a is smaller than that of the flat surface portion 27a in the first embodiment, it is possible to minimize vignetting of the light receiving portion 21 (see Figure 2) while maintaining the effective diameter of the distance measuring light 32 and the tracking light 35.

[0077] In the first and second embodiments, the light-projecting unit 19 has the distance-measuring light emitting unit 28 and the tracking light emitting unit 29, and the light-receiving unit 21 has the distance-measuring light receiving unit 41 and the tracking light receiving unit 42, but if tracking of the object to be measured is not required, the tracking light emitting unit 29 and the tracking light receiving unit 42 may be omitted. By omitting the tracking light emitting unit 29, the distance-measuring light emitting unit 28 can be provided inside the vertical rotation shaft 11, and the optical system of the distance measuring unit can be further miniaturized.

[0078] In the first and second embodiments, the reflecting surface of the light-receiving mirror 15 is flat, but the reflecting surface may be an off-axis parabolic mirror, a free-form surface mirror, or an annular free-form surface mirror. This allows the focal length of the light-receiving unit 21 to be shortened, the optical system to be made more compact, and the light-receiving lens 46 to be omitted, thereby reducing the number of parts.

[0079] Furthermore, in the first and second embodiments, the exit planes (flat planes 27a, 53a) of the cylindrical lenses 27, 53 in the light-projecting mirrors 24, 54 and the entrance planes (entrance end surfaces of the cylindrical portions 26a) of the rod mirror 26 are perpendicular to the distance measurement optical axis 25 and the tracking optical axis 36, but they may be slightly tilted (for example, by about 0.5° to 2°). This reduces the surface reflected light returning to the light-emitting element 31 and the tracking light-emitting element 37, and suppresses fluctuations in the output of the light-emitting element 31 and the tracking light-emitting element 37. When the exit planes of the cylindrical lenses 27, 53 and the entrance planes of the rod mirror 26 are tilted, the tilt angle is the same, and the tilt direction is set so that the deflection angle of the exit optical axis relative to the incident optical axis is perpendicular.

[0080] Next, a third embodiment of the present invention will be described with reference to Figures 6(A), 6(B), and 7(A) to 7(C). In Figures 6(A), 6(B), and 7(A) to 7(C), the same components as those in Figures 5(A) to 5(C) are designated by the same reference numerals, and their description will be omitted.

[0081] In the first and second embodiments, the window portion 39 (see FIG. 1) rotates integrally with the light-receiving mirror 15 (see FIG. 1), but in the third embodiment, the window portion 56 is fixed, and only the light-receiving mirror 15 rotates.

[0082] The window 56 is, for example, cylindrical with a portion of its circumferential surface removed, and is attached to the bottom surface of the recess 22 (see FIG. 1) via the removed portion. In this case, the axis of the window 56 coincides with or is parallel to the axis 11a of the vertical rotation shaft 11 (see FIG. 1).

[0083] Therefore, the entire periphery of the light receiving mirror 15 is covered by the window 56 except for the portion blocked by the base 5 (see FIG. 1), so that the distance measuring light 32 reflected by the light projecting mirror 57, which serves as a light projecting optical axis deflector, passes through the window 56 regardless of the emission direction. In addition, since the axis of the window 56 coincides with or is parallel to the axis 11a, the angle of incidence of the distance measuring light 32 with respect to the window 56 is always constant. The window 56 may be conical.

[0084] On the other hand, since the entrance surface of the window portion 56 is a curved surface having a predetermined curvature, astigmatism occurs when the distance measurement light 32 passes through the window portion 56. When astigmatism occurs, the distance measurement light 32 having a circular beam cross section that enters the window portion 56 exits the window portion 56 as the distance measurement light 32 having an elliptical beam cross section.

[0085] The light-projecting mirror 57 in the third embodiment is composed of a rod mirror 58 having a cylindrical portion 58a and a reflecting surface 58b, and a cylindrical lens 59 having a flat portion 59a and a recessed portion 59b, similar to the light-projecting mirror 54 in the second embodiment (see FIG. 5).

[0086] On the other hand, the flat surface 59a, which is the incident surface of the distance measurement light 32 reflected by the reflecting surface 58b and is the exit surface through which the distance measurement light 32 passes and exits, is a convex cylindrical surface. Therefore, in the following description, the flat surface 59a will also be referred to as the exit surface 59a.

[0087] The exit surface 59a is a convex cylindrical surface with R=1000 mm, for example, and the curvature of the exit surface 59a is set in accordance with the curvature of the window portion 56. The direction of the axis of the exit surface 59a is a direction that can cancel out the astigmatism generated in the window portion 56, and is the same as the direction of the curvature of the window portion 56. In other words, the exit surface 59a is configured to reduce the distance measurement light 32 in the direction of the major axis of an ellipse generated by the astigmatism in the window portion 56.

[0088] The distance measurement light 32 incident on the light-projecting mirror 57 has its beam diameter reduced in a predetermined axial direction as it passes through the exit surface 59a, and enters the window portion 56 as the distance measurement light 32 having an elliptical beam cross section.

[0089] The distance measuring light 32 incident on the window 56 generates astigmatism in the process of passing through the window 56, and the beam diameter of the distance measuring light 32 is expanded in the direction of contraction at the exit surface 59 a. Therefore, the distance measuring light 32 is emitted from the window 56 as the distance measuring light 32 having a true circular beam diameter, and is irradiated onto the measurement object.

[0090] As described above, in the third embodiment, the exit surface 59a of the cylindrical lens 59 is a convex cylindrical surface, and the astigmatism occurring in the window portion 56 is corrected by the exit surface 59a.

[0091] Therefore, even if the window portion 56 is fixedly provided and has a cylindrical or conical shape that covers the periphery of the light-projecting mirror 57, and astigmatism is generated by the window portion 56, the astigmatism can be eliminated and the distance-measuring light 32 having a circular beam diameter can be obtained, thereby improving measurement accuracy.

[0092] In the third embodiment, the exit surface 59a of the cylindrical lens 59 is a convex cylindrical surface, and the exit surface 59a corrects astigmatism caused by the window portion 56, but the method of correcting astigmatism is not limited to this. For example, the entrance surface 58c of the rod mirror 58 (cylindrical portion 58a) may be a convex cylindrical surface, and astigmatism may be corrected by the entrance surface 58c, or the reflecting surface 58b of the rod mirror 58 may be a concave cylindrical surface, and astigmatism may be corrected by the reflecting surface 58b. If any one of the exit surface 59a, the entrance surface 58c, and the reflecting surface 58b is a cylindrical surface, the other surfaces will be flat.

[0093] Alternatively, the rod mirror 58 and the cylindrical lens 59 may be made of glass materials having different refractive indices, thereby correcting the astigmatism caused by the window portion 56 .

[0094] It goes without saying that the configuration in which any one of the exit surface 59a, the reflecting surface 58b, and the incident surface 58c is a cylindrical surface may be applied to the light projecting mirror 24 (see FIG. 4) in the first embodiment.

[0095] REFERENCE SIGNS LIST 1 Surveying instrument 3 Surveying instrument main body 5 Base section 11 Vertical rotation axis 15 Light receiving mirror 17 Calculation control section 19 Light projecting section 21 Light receiving section 23 Through hole 24 Light projecting mirror 28 Distance measuring light emitting section 32 Distance measuring light 41 Distance measuring light receiving section 48 Reflected distance measuring light

Claims

1. A distance measuring unit having a light emitting element that emits distance measuring light and a light receiving element that receives the reflected distance measuring light from a measuring object, a rotary deflection unit that irradiates the distance measuring light, a vertical rotary drive unit that rotates the rotary deflection unit in a vertical direction via a hollow vertical rotary shaft, a base unit on which the rotary deflection unit is provided, a horizontal rotary drive unit that rotates the base unit in a horizontal direction, and a calculation control unit that calculates the distance to the measuring object based on the result of receiving the reflected distance measuring light to the light receiving element. a control unit, the rotary deflection unit having a light projecting deflection unit formed in the center of the rotary deflection unit and deflecting the distance measuring light at a right angle, and a light receiving deflection unit formed other than at the center and deflecting the reflected distance measuring light at a right angle in the opposite direction to the light emitting element, the light receiving deflection unit having a through hole communicating with the hollow portion of the vertical rotation shaft and parallel to the optical axis of the distance measuring light, the light projecting deflection unit being positioned so that a portion of the light projecting deflection unit is fitted into the through hole.

2. The surveying device of claim 1, wherein the light receiving deflection unit is a cylinder having a reflective surface formed at its end for reflecting the optical axis of the distance measuring light at a right angle, and the light projecting deflection unit is a light projecting mirror, the light projecting mirror being fitted into the through hole and having a cylindrical portion for allowing the distance measuring light that has passed through the vertical rotation axis to enter at a right angle, a rod mirror having a reflective surface for reflecting the distance measuring light that has passed through the cylindrical portion, and a cylindrical lens integrated with the rod mirror.

3. A surveying device as claimed in claim 2, wherein the cylindrical lens has a concave portion having a curvature equal to that of the cylindrical portion, and a flat portion onto which the distance measuring light reflected by the reflecting surface is incident at a right angle, and the cylindrical portion and the concave portion are fitted together with no gaps.

4. A surveying instrument according to claim 3, wherein a chamfered portion having an inclination equal to the inclination of the reflecting surface of the light receiving deflection portion is formed at the base end of the cylindrical lens, and the reflecting surface and the chamfered portion are configured to come into contact with each other.

5. The surveying instrument according to claim 3, wherein said cylindrical lens is cylindrical with the same diameter as said cylindrical portion, and said flat portion is circular with the same diameter as said cylindrical portion.

6. A surveying instrument according to any one of claims 2 to 5, wherein the reflecting surface of the receiving deflection unit is an off-axis paraboloid or a free-form surface.

7. A surveying device as claimed in claim 2, further comprising a window portion which covers the periphery of the light-projecting mirror and is fixedly provided on the support portion, the window portion being cylindrical or conical in shape and coinciding with or parallel to the axis of the vertical rotation axis, and configured so that any one of the entrance surface of the cylindrical portion on which the distance-measuring light is incident, the reflecting surface, and the exit surface of the cylindrical lens on which the distance-measuring light reflected by the reflecting surface is incident at a right angle is a cylindrical surface.

Images