WO2025022966A1 - Surveying device - Google Patents

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

The present invention relates to a surveying device capable of acquiring the three-dimensional coordinates of a measurement object.

Surveying equipment such as laser scanners and total stations have optical distance measuring devices that detect the distance to the object being measured using prism distance measurement, which uses a retroreflective prism as the object being measured, and non-prism distance measurement, which does not use a reflecting prism.

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 deflection optical member is required to make the optical axis of the distance measuring light coaxial with the optical axis of the reflected distance measuring light, which leads to an increase in the size of the optical system and the entire surveying device.

US Patent Application Publication No. 2022/0373685

The present invention provides a surveying device that reduces the size of the optical system and the entire device.

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 the object to be measured, a rotary deflection unit that irradiates the distance measuring light, a vertical rotation drive unit that rotates the rotary deflection unit in the vertical direction via a hollow vertical rotation shaft, a base unit on which the rotary deflection unit is provided, a horizontal rotation drive unit that rotates the base unit in the horizontal direction, and a calculation control unit that calculates the distance to the object to be measured based on the result of receiving the reflected distance measuring light at the light receiving element. The rotating deflection unit has a light projecting deflection unit formed in the center of the rotating deflection unit and deflecting the distance measuring light at a right angle, and a light receiving deflection unit 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 unit is connected to the hollow part of the vertical rotation shaft and has a through hole parallel to the optical axis of the distance measuring light, and the light projecting deflection unit is arranged so that a part of the light projecting deflection unit is fitted into the through hole.

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

The present invention also relates to a surveying device in which the cylindrical lens has a concave portion 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 concave portion are configured to fit tightly together without any gaps.

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

The present invention also relates to a surveying device 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.

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

The present invention also relates to a surveying device that is further provided with a window section that covers the periphery of the light-projecting mirror and is fixedly provided on the support section, the window section being cylindrical or conical in shape and coinciding with or parallel to the axis of the vertical rotation axis, and that is configured so that any one of the entrance surface of the cylindrical section 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.

According to the present invention, 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 the object to be measured is provided, a rotary deflection unit that irradiates the distance measuring light, a vertical rotation drive unit that rotates the rotary deflection unit in the vertical direction via a hollow vertical rotation shaft, a base unit on which the rotary deflection unit is provided, a horizontal rotation drive unit that rotates the base unit in the horizontal direction, and a calculation control unit that calculates the distance to the object to be measured based on the result of receiving the reflected distance measuring light to the light receiving element, and the rotary deflection unit is The device has a light projecting deflection section formed in the center of the device that deflects the distance measuring light at a right angle, and a light receiving deflection section formed outside the center that deflects 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 part of the light projecting deflection section is fitted into the through hole, which eliminates the need to incorporate the light emitting element and the light receiving element into a single optical system, thereby enabling the optical system and the entire device to be made smaller.

FIG. 1 is a front sectional view showing a surveying instrument according to a first embodiment. FIG. 2 is an enlarged view of the main part showing the light projecting section and the light receiving section according to the first embodiment. 3A and 3B are explanatory diagrams for explaining the rotary deflection unit according to the first embodiment. 4A to 4C are explanatory diagrams for explaining the light projecting mirror according to the first embodiment. 5A to 5C are explanatory diagrams for explaining a light projecting mirror according to the second embodiment. FIG. 6A is a side view showing the relationship between a light projecting mirror and a window portion according to the third embodiment, and FIG. 6B is a perspective view showing the relationship between a light projecting mirror and a window portion according to the third embodiment. 7A to 7C are explanatory diagrams for explaining a light projecting mirror according to the third embodiment.

Below, an embodiment of the present invention will be explained with reference to the drawings.

First, a surveying device according to a first embodiment of the present invention will be described with reference to Figures 1 and 2.

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

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

The surveying device main body 3 is equipped with (contains) a fixed section 4, a support 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 detection section, 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 detection section, a light receiving mirror 15, an operation panel 16 that serves both as an operation section and a display section, a calculation control section 17, a memory section 18, a light projecting section 19, a light receiving section 21, etc. The calculation control section 17 is a CPU specialized for this device or a general-purpose CPU.

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 supported rotatably by the horizontal rotation bearing 7. The support part 5 is supported by the horizontal rotation shaft 6, and the support part 5 rotates horizontally together with the horizontal rotation shaft 6.

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

The relative rotation angle of the support part 5 with respect to the fixed part 4 is detected by the horizontal angle encoder 9. The 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 of the horizontal rotation motor 8 based on the horizontal angle data.

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.

A recess 22 is formed in the support portion 5. The vertical rotation shaft 11 is hollow, and one end of the shaft 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 stored in the recess 22.

The light receiving mirror 15 is a cylinder formed by cutting the end of a cylindrical glass or metal material such as aluminum to form a reflective surface on the end. The reflective surface is flat and is configured to deflect the incident light receiving optical axis 43 (described later) 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. In addition, a cylindrical through hole 23 that communicates with the hollow part of the vertical rotation shaft 11 and is concentric with the vertical rotation shaft 11 is formed in the center of the light receiving mirror 15. One end of the through hole 23 opens into the recess 22 via the reflective surface of the light receiving mirror 15, and the lower end of the opening protrudes a predetermined distance laterally beyond the upper end of the opening end.

Also, a part of the light projecting mirror 24 is glued to fit into 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 the horizontally incident distance measuring optical axis 25 (described later) at a right angle.

As shown in Figures 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 so as to be in close contact with and integrated with the rod mirror 26. In the following explanation, 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.

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 45° and evaporating a metal film or a dielectric multilayer film onto 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 coinciding with the axis of the rod mirror 26.

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 enter the rectangular flat surface portion 27a of the cylindrical lens 27 at a right angle with 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.

In addition, 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 by the cylindrical lens 27.

Therefore, the distance measurement optical axis 25 does not deflect at the boundary between the rod mirror 26 and the cylindrical lens 27. In addition, all light passing through the cylindrical portion 26a can be made to enter the flat portion 27a.

The base end of the cylindrical lens 27 is formed with a chamfered portion 27c that is chamfered so as to slope from the base end side to the tip end side from top to bottom, 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 and the light receiving light axis 43 incident on the light receiving mirror 15 match, and further the axis of the cylindrical portion 26a and the distance measuring light axis 25 match. In other words, the chamfered portion 27c acts as a positioning mechanism for the light projecting mirror 24.

The vertical angle encoder 14 is provided at the other end of the vertical rotation shaft 11. The light projector 19 is provided at a position away from the other end of the vertical rotation shaft 11. The light projector 19 is composed of a distance measuring light emitting unit 28 and a tracking light emitting unit 29.

The distance measurement light emitting unit 28 has the distance measurement light axis 25. The distance measurement light emitting unit 28 also has, in order from the light emitting side, a light emitting element 31 arranged on the distance measurement light 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 arranged on the transmitted light axis of the dichroic mirror 34.

The dichroic mirror 34 has optical properties that transmit the distance measurement light 32 and reflect the tracking light 35. The dichroic mirror 34 is also 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 the 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 transmitted through the dichroic mirror 34. Therefore, the distance measurement light 32 and the tracking light 35 are incident on the light projecting mirror 24 on the same axis and are reflected at a right angle by the light projecting mirror 24.

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.

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 of a wavelength different from that of the distance measuring light 32 as the tracking light 35, a tracking projection lens 38, the dichroic mirror 34, and the projection mirror 24 provided on the reflected optical axis of the dichroic mirror 34.

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

The vertical rotation motor 13 is provided on the vertical rotation shaft 11, and the vertical rotation motor 13 is controlled by the calculation control unit 17. The calculation 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 are rotated around the axis 11a.

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 of the vertical rotation motor 13 based on the vertical angle data.

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

The memory unit 18 stores various programs such as a sequence program that controls the distance measurement operation, a calculation program that calculates distance by the distance measurement operation, a calculation program that calculates an angle based on horizontal angle data and vertical angle data, a program that calculates the three-dimensional coordinates of a desired measurement point based on distance and angle, a tracking program for tracking a target, etc. In addition, various processes are performed by the calculation control unit 17 executing various programs.

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

Next, the light receiving unit 21 will be described with reference to FIG. 2. In this embodiment, a target having retroreflective properties, such as a prism, is used as the measurement object.

The light receiving unit 21 has a distance measuring light receiving unit 41 and a tracking light receiving unit 42. The distance measuring unit is composed of the distance measuring light emitting unit 28 and the distance measuring light receiving unit 41, and the tracking light emitting unit 29 and the tracking light receiving unit 42 form a tracking unit.

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 arranged on the light receiving optical axis 43, a light receiving prism 45, and a light receiving lens 46.

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. In addition, the dichroic film 47 has the optical property of reflecting the reflected distance measuring light 48 and transmitting the reflected tracking light 49.

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.

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 arranged on the tracking light receiving optical axis 51, the light receiving prism 45, and the light receiving lens 46. 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.

The tracking light receiving element 52 is a CCD or CMOS sensor that is a collection of pixels, and the position of each pixel on the tracking light receiving element 52 can be identified. 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 identified by the pixel coordinates.

The light projecting unit 19 and the light receiving unit 21 are controlled by the calculation 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 inside of the vertical rotation shaft 11 and the through hole 23, and is incident at a right angle to the base end surface of the cylindrical portion 26a of the rod mirror 26 at an incident angle of 0°.

The distance measuring 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 measuring light 32 reflected by the reflecting surface 26b enters the cylindrical lens 27 through the recess 27b, enters the flat portion 27a at an angle of incidence of 0°, and is emitted.

The distance measuring light 32 enters the cylindrical portion 26a at an angle of incidence of 0° and exits from the flat portion 27a, so no deflection occurs in the distance measuring light 32 when it enters and exits. In addition, the cylindrical lens 27 of the rod mirror 26 is integrated without any gaps, so no deflection occurs when the distance measuring light 32 passes through the boundary surface between the rod mirror 26 and the cylindrical lens 27.

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) perpendicular to the axis 11a and within a plane including the axis 6a.

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.

The receiving optical axis 43 of the reflected distance measuring light 48 reflected by the receiving mirror 15 is coaxial with the distance measuring optical axis 25 transmitted through the dichroic mirror 34. In other words, the distance measuring optical axis 25 and the receiving optical axis 43 coincide with the axis 11a.

In addition, the window portion 39 is inclined at a predetermined angle with respect to the distance measurement optical axis 25, so that 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.

The calculation control unit 17 performs distance measurement for each pulse of the distance measuring light 32 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 (Time Of Flight). The light emission timing of the light emitting element 31, i.e., the pulse interval, can be changed via the operation panel 16. In addition, 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.

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 scan the distance measuring light 32 two-dimensionally. Furthermore, by detecting the vertical angle and horizontal angle for each pulse 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 measuring data, the three-dimensional coordinates of the measurement object and three-dimensional point cloud data corresponding to the measurement object can be obtained.

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 inside of the vertical rotation shaft 11 and the through hole 23, and is incident at a right angle on the cylindrical portion 26a of the rod mirror 26 at an incident angle of 0°, and 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 through the recess 27b, is incident on and emitted from the flat portion 27a at an incident angle of 0°, and is irradiated onto the measurement object through the window portion 39.

The reflected tracking light 49 is irradiated onto the object to be measured coaxially with the distance measuring light 32 and is reflected coaxially from the object to be measured. It 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. In the process of passing through the light receiving prism 45, 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, passes through the dichroic film 47, and is received by the tracking light receiving element 52. In addition, a tracking image (not shown) can be obtained by receiving the reflected tracking light 49 at the tracking light receiving element 52.

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 drive the horizontal rotation motor 8 and the vertical rotation motor 13 based on the position deviation to track the object to be measured.

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, there is no need to incorporate the light-projecting unit 19 and the light-receiving unit 21 into a single optical system, and no deflection optical member is required to deflect the distance measuring light 32 and the reflected distance measuring light 48 so that they are coaxial. This reduces the number of parts and allows the optical system and the surveying device 1 as a whole to be made more compact.

The rod mirror 26 and the cylindrical lens 27 form the light projecting mirror 24, and the rod mirror 26 and the cylindrical lens 27 are integrated together 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.

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. This allows the effective diameter of the distance measuring light 32 and the tracking light 35 to be expanded to approximately the same diameter as 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 to be emitted.

In addition, the chamfered portion 27c is formed at the base end of the cylindrical lens 27 with an inclination equivalent to that of the light receiving mirror 15. By bringing the chamfered portion 27c into contact with the light receiving mirror 15, the light projecting mirror 24 can be automatically positioned, improving workability and reducing work time.

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 26a 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.

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, improving the measurement accuracy.

Furthermore, 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, manufacturing is easy and manufacturing costs can be reduced.

Next, a second embodiment of the present invention will be described with reference to Figures 5(A) to 5(C). Note that in Figures 5(A) to 5(C), the same reference numerals are used for the same parts as in Figures 4(A) to 4(C), and their description will be omitted.

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

Also, as shown in FIG. 5(C), 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 no gaps between the inner surface of the recess 53b and the circumferential surface of the cylindrical portion 26a. The rest of the configuration is the same as in the first embodiment.

In the second embodiment, the cylindrical lens 53 has a cylindrical shape with a diameter equal to that of the cylindrical portion 26a of the rod mirror 26, and the rod mirror 26 and the cylindrical lens 53 are tightly integrated with no gaps via the recess 53b, forming the light projecting mirror 54.

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

In the second embodiment, the entire amount 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 surface portion 53a. This allows the effective diameter of the distance measuring light 32 and the tracking light 35 to be expanded to approximately the same diameter as 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 to be emitted.

In addition, the incident area of the reflected distance measuring light 48 on the flat surface 53a is smaller than that of the flat surface 27a in the first embodiment, so that the effective diameter of the distance measuring light 32 and the tracking light 35 is maintained while minimizing vignetting of the light receiving section 21 (see FIG. 2).

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, making it possible to further miniaturize the optical system of the distance measuring unit.

In the first and second embodiments, the reflecting surface of the light receiving mirror 15 is a flat surface, 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 section 21 to be shortened, the optical system to be made more compact, and the light receiving lens 46 can be omitted, reducing the number of parts.

Furthermore, in the first and second embodiments, the exit plane (plane 27a, 53a) of the cylindrical lens 27, 53 in the light projecting mirror 24, 54 and the entrance plane (entrance end surface of the cylindrical portion 26a) of the rod mirror 26 are perpendicular to the distance measuring optical axis 25 and the tracking optical axis 36, but they may be slightly tilted (for example, 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 output fluctuations of the light emitting element 31 and the tracking light emitting element 37. When the exit plane of the cylindrical lens 27, 53 and the entrance plane 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.

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). Note that in Figures 6(A), 6(B), and 7(A) to 7(C), the same reference numerals are used for elements equivalent to those in Figures 5(A) to 5(C), and their description will be omitted.

In the first and second embodiments, the window portion 39 (see FIG. 1) rotates together 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.

The window portion 56 is, for example, cylindrical with a portion of the periphery cut away, and is attached to the bottom surface of the recess 22 (see FIG. 1) via the cut away portion. In addition, at this time, the axis of the window portion 56 coincides with or is parallel to the axis 11a of the vertical rotation shaft 11 (see FIG. 1).

Therefore, the entire periphery of the light receiving mirror 15 is covered by the window portion 56 except for the portion blocked by the support portion 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 deflection portion, passes through the window portion 56 regardless of the emission direction. In addition, since the axis of the window portion 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 portion 56 is always constant. The window portion 56 may be cone-shaped.

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 is emitted from the window portion 56 as the distance measurement light 32 having an elliptical beam cross section.

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).

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

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 to match the curvature of the window portion 56. The axis of the exit surface 59a is oriented in a direction that can offset the astigmatism that occurs in the window portion 56, and is the same as the curvature direction 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 that occurs due to the astigmatism in the window portion 56.

The distance measuring 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 measuring light 32 having an elliptical beam cross section.

The distance measuring light 32 incident on the window 56 generates astigmatism as it passes through the window 56, expanding the beam diameter of the distance measuring light 32 in the direction of the reduction at the exit surface 59a. Therefore, the distance measuring light 32 is emitted from the window 56 as distance measuring light 32 having a circular beam diameter, and is irradiated onto the object to be measured.

As described above, in the third embodiment, the exit surface 59a of the cylindrical lens 59 is a convex cylindrical surface, and the exit surface 59a corrects the astigmatism that occurs in the window portion 56.

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 the measurement accuracy.

In the third embodiment, the exit surface 59a of the cylindrical lens 59 is a convex cylindrical surface, and the exit surface 59a corrects the 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 (cylinder portion 58a) may be a convex cylindrical surface, and the entrance surface 58c may correct the astigmatism, or the reflecting surface 58b of the rod mirror 58 may be a concave cylindrical surface, and the reflecting surface 58b may correct the astigmatism. In addition, if any of the exit surface 59a, the entrance surface 58c, and the reflecting surface 58b is a cylindrical surface, the other surface will be a flat surface.

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

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

REFERENCE SIGNS LIST 1 Surveying instrument 3 Surveying instrument 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 (7)

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 the object to be measured, a rotary deflection unit that irradiates the distance measuring light, a vertical rotation drive unit that rotates the rotary deflection unit in the vertical direction via a hollow vertical rotation shaft, a base unit on which the rotary deflection unit is provided, a horizontal rotation drive unit that rotates the base unit in the horizontal direction, and a calculation unit that calculates the distance to the object to be measured based on the result of receiving the reflected distance measuring light at the light receiving element. A surveying device comprising 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 outside 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 communicating with the hollow part of the vertical rotation shaft and having a through hole parallel to the optical axis of the distance measuring light, the light projecting deflection unit being positioned so that a part of the light projecting deflection unit is fitted into the through hole. The surveying device of claim 1, wherein the light receiving deflection unit is a cylinder having a reflecting surface formed at the 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 reflecting surface for reflecting the distance measuring light that has passed through the cylindrical portion, and a cylindrical lens integrated with the rod mirror. The surveying device of 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 configured to fit closely together without any gaps. The surveying device of claim 3, in which 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. The surveying device of claim 3, wherein 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. The surveying device 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. The surveying device of claim 2 further comprises a window section that covers the periphery of the light projecting mirror and is fixedly provided on the support section, the window section being cylindrical or conical in shape and coinciding with or parallel to the axis of the vertical rotation shaft, and configured so that any one of the entrance surface of the cylindrical section 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.

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