Measuring device

Abstract

This invention provides a surveying device that miniaturizes the optical system and the overall device. [Solution] The system comprises a distance measuring light emission unit 24 that emits distance measuring light 31 to an object to be measured, a distance measuring light receiving unit 25 having a light receiving unit 39 that receives reflected distance measuring light from the object to be measured, and a calculation control unit that controls the distance measuring light emission unit and calculates the distance to the object to be measured based on the result of receiving the reflected distance measuring light to the light receiving unit. The distance measuring light receiving unit has a light receiving lens 44 that focuses the reflected distance measuring light and a reflective mirror 45 provided opposite the light receiving lens. A reflective surface is formed in the center of the surface of the light receiving lens that faces the reflective mirror, and the reflected distance measuring light that has passed through the light receiving lens is configured to be reflected back and forth between the reflective mirror and the reflective surface along the optical axis 38 of the reflected distance measuring light.

Description

Technical Field

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

Background Art

[0002] Surveying instruments such as laser scanners and total stations have a light wave distance measuring device that detects the distance to a measurement object by prism distance measurement using a prism having retroreflectivity as a measurement object and non-prism distance measurement without using a reflecting prism.

[0003] The light receiving part of the light wave distance measuring device has an optical system including a lens, and the reflected distance measuring light is imaged on the light receiving surface by the refraction action of the lens. The objective lens of the optical system has a focal length f, and the light receiving part requires a size capable of accommodating the optical system and a length in the optical axis direction capable of securing the focal length f. Therefore, due to the limitations of the size of the optical system and the focal length, it is difficult to miniaturize the light receiving part.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention provides a surveying instrument that miniaturizes the optical system and aims to miniaturize the entire device.

Means for Solving the Problems

[0006] The present invention relates to a measuring device comprising: a distance measuring light emission unit that emits distance measuring light onto an object to be measured; a distance measuring light receiving unit having a light receiving unit that receives reflected distance measuring light from the object to be measured; and a calculation control unit that controls the distance measuring light emission unit and calculates the distance to the object to be measured based on the result of receiving the reflected distance measuring light to the light receiving unit, wherein the distance measuring light receiving unit has a light receiving lens that focuses the reflected distance measuring light and a reflective mirror provided opposite the light receiving lens, a reflective surface is formed in the center of the surface of the light receiving lens that faces the reflective mirror, and the reflected distance measuring light that has passed through the light receiving lens is configured to be reflected back and forth between the reflective mirror and the reflective surface along the optical axis of the reflected distance measuring light.

[0007] The present invention further comprises a light-receiving reflective prism provided on the reflective mirror, wherein the light-receiving reflective prism is configured to deflect the reflected distance-measuring light reflected from the reflective surface at a right angle or approximately a right angle.

[0008] Furthermore, the present invention relates to a surveying device in which the reflective mirror further has a hole formed in its center, and the reflected distance measuring light reflected from the reflective surface passes through the hole.

[0009] The present invention also relates to a surveying device comprising a scanning mirror that rotates and illuminates the distance measuring light, a deflection optical member that deflects the distance measuring light so that it aligns with the rotation axis of the scanning mirror, and a parallel plane plate provided on the scanning mirror side of the light receiving lens, wherein the deflection optical member is joined to the surface of the parallel plane plate on the scanning mirror side.

[0010] The present invention also relates to a surveying device comprising a scanning mirror that rotates and illuminates the distance measuring light, a deflection optical member that deflects the distance measuring light so that it aligns with the rotation axis of the scanning mirror, and a parallel plane plate provided on the scanning mirror side of the light receiving lens, wherein the deflection optical member is bonded to the surface of the parallel plane plate on the light receiving lens side.

[0011] The present invention also relates to a surveying device comprising a tracking light emission unit that emits tracking light coaxially with the distance measuring light onto the object to be measured, and a tracking light receiving unit having a tracking light receiving element that receives reflected tracking light reflected coaxially from the object to be measured, wherein a dichroic prism having a separation surface that separates the reflected distance measuring light and the reflected tracking light is arranged on the reflected light axis of the light receiving and reflecting prism.

[0012] The present invention also relates to a surveying device comprising a tracking light emission unit that emits tracking light coaxially with the distance measuring light onto the object to be measured, and a tracking light receiving unit having a tracking light receiving element that receives reflected tracking light reflected coaxially from the object to be measured, wherein the light receiving and reflecting prism is a dichroic prism having a separation surface that separates the reflected distance measuring light and the reflected tracking light.

[0013] The present invention also relates to a surveying device comprising a tracking light emission unit that emits tracking light coaxially with the distance measuring light onto the object to be measured, and a tracking light receiving unit having a tracking light receiving element that receives reflected tracking light reflected coaxially from the object to be measured, wherein a dichroic prism having a separating surface that separates the reflected distance measuring light and the reflected tracking light is arranged on the optical axes of the reflected distance measuring light and the reflected tracking light passing through the hole.

[0014] The present invention further comprises a scanning mirror that rotates and irradiates the distance measuring light, and a deflecting optical member that deflects the distance measuring light so that it aligns with the rotation axis of the scanning mirror, wherein a flat portion is formed in the center of the incident surface of the light receiving lens, and the deflecting optical member is joined to the flat portion.

[0015] The present invention further comprises a scanning mirror that rotates and irradiates the distance measuring light, and a deflecting optical member that deflects the distance measuring light so that it aligns with the rotation axis of the scanning mirror, wherein a hole is formed in the center of the incident surface of the light receiving lens, and the deflecting optical member is joined to the hole.

[0016] Furthermore, the present invention relates to a surveying device in which the deflection optical member comprises a cylindrical portion having an imaging unit having an imaging optical axis coaxial with the distance measuring light, and a cylindrical mirror having a dichroic mirror that reflects the distance measuring light and transmits visible light. [Effects of the Invention]

[0017] According to the present invention, the device comprises a distance measuring light emission unit that emits distance measuring light onto an object to be measured, a distance measuring light receiving unit having a light receiving unit that receives reflected distance measuring light from the object to be measured, and a calculation control unit that controls the distance measuring light emission unit and calculates the distance to the object to be measured based on the result of receiving the reflected distance measuring light to the light receiving unit. The distance measuring light receiving unit has a light receiving lens that focuses the reflected distance measuring light and a reflective mirror provided opposite the light receiving lens, and a reflective surface is formed in the center of the surface of the light receiving lens that faces the reflective mirror, and the reflected distance measuring light that has passed through the light receiving lens is configured to be reflected back and forth between the reflective mirror and the reflective surface along the optical axis of the reflected distance measuring light, thereby shortening the length of the reflected distance measuring light in the optical axis direction, which has the excellent effect of enabling miniaturization of the optical system and the overall device. [Brief explanation of the drawing]

[0018] [Figure 1] This is a cross-sectional view showing a surveying device according to the first embodiment. [Figure 2] This is a diagram showing the distance measuring unit according to the first embodiment. [Figure 3] This is a diagram showing the distance measuring unit according to the second embodiment. [Figure 4] This is a diagram showing the distance measuring unit according to the third embodiment. [Figure 5] This is a diagram showing the distance measuring unit according to the fourth embodiment. [Figure 6] This is a configuration diagram showing the distance measuring unit according to the fifth embodiment. [Figure 7] (A) is a diagram showing the distance measuring unit according to the first modified example, and (B) is a diagram showing the distance measuring unit according to the second modified example. [Figure 8](A) is a configuration diagram showing a distance measurement unit according to a third modification example, and (B) is a configuration diagram showing a distance measurement unit according to a fourth modification example. [Figure 9] (A) and (B) are explanatory diagrams each showing a light receiving lens, and (C) is an explanatory diagram showing a modification example of a deflection optical member.

Embodiments for Carrying out the Invention

[0019] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0020] First, in FIG. 1, a surveying instrument according to a first embodiment of the present invention will be described.

[0021] The surveying instrument 1 is, for example, a laser scanner, and includes an alignment unit 2 attached to a tripod (not shown) and a surveying instrument main body 3 attached to the alignment unit 2.

[0022] The alignment unit 2 has an alignment screw 10, and the surveying instrument main body 3 is aligned horizontally by the alignment screw 10.

[0023] The surveying instrument main body 3 includes a fixed part 4, a carriage part 5, a horizontal rotation axis 6, a horizontal rotation bearing 7, a horizontal rotation motor 8 as a horizontal rotation drive part, a horizontal angle encoder 9 as a horizontal angle detection part, a vertical rotation axis 11, a vertical rotation bearing 12, a vertical rotation motor 13 as a vertical rotation drive part, a vertical angle encoder 14 as a vertical angle detection part, a scanning mirror 15, an operation panel 16 that also serves as an operation part and a display part, an arithmetic control part 17, a storage part 18, a distance measurement part 19, and the like. Here, as the arithmetic control part 17, a CPU specialized for this device or a general-purpose CPU is used.

[0024] The horizontal rotation bearing 7 is fixed to the fixed part 4. The horizontal rotation axis 6 has a vertical axis center 6a, and the horizontal rotation axis 6 is rotatably supported by the horizontal rotation bearing 7. Further, the carriage part 5 is supported by the horizontal rotation axis 6, and the carriage part 5 rotates integrally with the horizontal rotation axis 6 in the horizontal direction.

[0025] A horizontal rotation motor 8 is provided between the horizontal rotation bearing 7 and the support portion 5, and the horizontal rotation motor 8 is controlled by the calculation control unit 17. The calculation control unit 17 uses the horizontal rotation motor 8 to rotate the support portion 5 around the axis 6a.

[0026] The relative rotation angle of the support unit 5 with respect to the fixed unit 4 is detected by the horizontal angle encoder 9. The detection signal from the horizontal angle encoder 9 is input to the calculation control unit 17, and the calculation control unit 17 calculates the horizontal angle data. Based on the horizontal angle data, the calculation control unit 17 performs feedback control to the horizontal rotation motor 8.

[0027] Furthermore, the mounting portion 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 body 3.

[0028] A recess 21 is formed in the mounting portion 5. One end of the vertical rotation shaft 11 extends into the recess 21, and the scanning mirror 15 is fixed to this end, with the scanning mirror 15 housed in the recess 21. The other end of the vertical rotation shaft 11 is provided with the vertical angle encoder 14.

[0029] A window portion 22 is provided on the axis 6a, opposite the scanning mirror 15, which is made of a transparent material such as glass and rotates integrally with the scanning mirror 15. The window portion 22 is inclined at a predetermined angle with respect to the axis 6a. The scanning mirror 15 and the window portion 22 together constitute a vertical rotating part that is rotated vertically integrally via the vertical rotation shaft 11 by the vertical rotation motor 13.

[0030] A vertical rotation motor 13 is provided on the vertical rotation axis 11, and the vertical rotation motor 13 is controlled by the calculation control unit 17. The calculation control unit 17 rotates the vertical rotation axis 11 using the vertical rotation motor 13, and the scanning mirror 15 rotates around the axis 11a.

[0031] The rotation angle of the scanning 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 the vertical angle data of the scanning mirror 15 based on the detection signal and performs feedback control to the vertical rotation motor 13 based on the vertical angle data.

[0032] Furthermore, the horizontal angle data, vertical angle data, and measurement results calculated by the calculation control unit 17 are stored in the storage unit 18. Various storage means can be used as the storage unit 18, such as an HDD as a magnetic storage device, a CD or DVD as an optical storage device, or a memory card or USB memory as a semiconductor storage device. The storage unit 18 may be detachable from the mounting unit 5, or it may be capable of sending data to an external storage device or external data processing device via a communication means (not shown).

[0033] The storage unit 18 stores various programs, including a sequence program for controlling the distance measurement operation, a calculation program for calculating distance based on the distance measurement operation, a calculation program for calculating angles based on horizontal angle data and vertical angle data, and a program for calculating the three-dimensional coordinates of a desired measurement point based on distance and angle. Furthermore, various processes are executed by the calculation control unit 17 when these programs are executed.

[0034] The aforementioned operation panel 16 is, for example, a touch panel, and serves as both an operation unit for giving instructions for distance measurement and changing measurement conditions, such as the interval between measurement points, and a display unit for displaying distance measurement results, images, etc.

[0035] Next, the distance measuring unit 19 will be described with reference to Figure 2. In the first embodiment, the light-receiving lens 44 (described later) has a focal length f = 110 mm and an objective effective diameter of φ50 mm. In other embodiments, the same light-receiving lens 44 is used.

[0036] The distance measuring unit 19 includes a distance measuring light emission unit 24, a distance measuring light receiving unit 25, a tracking light emission unit 26, and a tracking light receiving unit 27. The distance measuring unit is composed of the distance measuring light emission unit 24 and the distance measuring light receiving unit 25, and the tracking unit is composed of the tracking light emission unit 26 and the tracking light receiving unit 27.

[0037] The distance measuring light emission unit 24 has a distance measuring optical axis 28. The distance measuring light emission unit 24 includes, in order from the light-emitting side, a light-emitting element 29 provided on the distance measuring optical axis 28, for example, a laser diode (LD) that emits near-infrared light of a predetermined wavelength as distance measuring light 31, a light-emitting lens 32, a dichroic mirror 33, and a mirror 34 provided on the transmission optical axis of the dichroic mirror 33. A deflection optical member, for example, a reflective prism 35, is provided on the reflected optical axis of the mirror 34, and the scanning mirror 15 is provided on the reflected optical axis of the reflective prism 35. Furthermore, the window portion 22 is provided on the reflected optical axis of the scanning mirror 15.

[0038] In this embodiment, the distance measuring optical axis 28, the distance measuring optical axis 28 reflected by the mirror 34, the distance measuring optical axis 28 reflected by the reflective prism 35, and the distance measuring optical axis 28 reflected by the scanning mirror 15 are collectively referred to as the distance measuring optical axis 28.

[0039] The dichroic mirror 33 has optical properties that transmit the distance measuring light 31 and reflect the tracking light 36 (described later). Furthermore, the dichroic mirror 33 is installed on the common optical path of the distance measuring light 31 and the tracking light 36 (at the intersection of the distance measuring optical axis 28 and the tracking optical axis 37 (described later)), and deflects (reflects) the tracking optical axis 37 so that it aligns with the distance measuring optical axis 28. Therefore, the distance measuring light 31 and the tracking light 36 are irradiated coaxially toward the object to be measured.

[0040] The reflective prism 35 is configured to deflect (reflect) the light such that the distance measuring optical axis 28 and the tracking optical axis 37 coincide with the light receiving optical axis 38 (described later) and the axis 11a. The reflective surface of the reflective prism 35 may be tilted at an angle of 45°, or it may be an angle other than 45°, so as to reflect the distance measuring light 31 and the tracking light 36 at a right angle. The tilt angle of the reflective surface of the reflective prism 35 is appropriately designed, for example, in the range of about 40° to 50°. The reflective prism 35 may be a triangular prism as shown in Figure 2, or a cylindrical mirror.

[0041] The distance measuring light receiving unit 25 has the light receiving optical axis 38. The distance measuring light receiving unit 25 also includes, in order from the light receiving side, a light receiving optical fiber 39 as a light receiving unit provided on the light receiving optical axis 38, a dichroic prism 41, a relay lens 42 provided on the reflective optical axis of the dichroic prism 41, a light receiving reflective prism 43, a light receiving lens 44 provided on the reflective optical axis of the light receiving reflective prism 43, and a reflective mirror 45 as a first reflecting unit provided on the reflective optical axis of the light receiving lens 44.

[0042] The receiving optical fiber 39 is configured to receive reflected ranging light 46 (described later) and transmit the received signal to the arithmetic control unit 17. The dichroic prism 41 is constructed by joining two prisms, and the joining surface is a separation surface 41a on which a dichroic film is deposited. The separation surface 41a has optical properties that reflect the reflected ranging light 46 and transmit the tracking light 36 (reflected tracking light 52) ​​that is incident coaxially with the reflected ranging light 46. In other words, the separation surface 41a functions as a separation surface that separates the reflected ranging light 46 and the reflected tracking light 52.

[0043] The relay lens 42 is a group of convex lenses composed of multiple lenses, and is configured to focus the reflected distance measuring light 46 onto the light-receiving end face of the light-receiving optical fiber 39. The light-receiving and reflecting prism 43 is, for example, a triangular prism, and is configured to deflect (reflect) the reflected distance measuring light 46 toward the relay lens 42 at a right angle or approximately a right angle. Here, a right angle means 90°, and approximately a right angle means an angle of about 85° to 95°, excluding 90°. Therefore, in the following description, when a right angle or approximately a right angle is written, it means 85° to 95°.

[0044] The light-receiving lens 44 is a lens having a predetermined Numerical Aperture (NA), and the surface facing the scanning mirror 15 (incident surface) is flat. The surface facing the light-receiving reflective prism 43, i.e., the surface opposite to the scanning mirror 15 (exit surface), is an aspherical surface, an annular aspherical surface, or a convex surface of an axially symmetric freeform surface. The reflective prism 35 is attached to the center of the surface facing the scanning mirror 15 of the light-receiving lens 44.

[0045] Furthermore, a mirror coating is applied to the center of the surface of the light-receiving lens 44 that faces the light-receiving reflective prism 43, forming a reflective surface 44a as a second reflective portion. An anti-reflection (AR) coating is applied to the parts of the light-receiving lens 44 other than the center, forming a transmissive surface 44b. Therefore, the reflective surface 44a is formed on the back surface of the reflective prism 35, and the size of the reflective surface 44a is, for example, equivalent to or approximately equivalent to the bottom area of ​​the reflective prism 35.

[0046] The reflective mirror 45 is a plate-shaped mirror, with the light-receiving and reflecting prism 43 joined to its center. The size of the reflective mirror 45 is such that, for example, all of the reflected distance-measuring light 46 that has passed through the light-receiving lens 44 and been focused can enter it.

[0047] In this embodiment, the light-receiving optical axis 38, the light-receiving optical axis 38 reflected by the dichroic prism 41 (separation surface 41a), the light-receiving optical axis 38 reflected by the light-receiving and reflecting prism 43, the light-receiving optical axis 38 reflected by the light-receiving lens 44 (reflection surface 44a), the light-receiving optical axis 38 reflected by the reflection mirror 45, and the light-receiving optical axis 38 reflected by the scanning mirror 15 are collectively referred to as the light-receiving optical axis 38.

[0048] The tracking light emission unit 26 has the tracking optical axis 37. The tracking light emission unit 26 also has, in order from the light-emitting side, a tracking light-emitting element 47 provided on the tracking optical axis 37, for example a laser diode (LD) that emits near-infrared light with a different wavelength from the distance measuring light 31 as the tracking light 36, a tracking light projection lens 48, and the dichroic mirror 33, as well as the mirror 34 provided on the reflective optical axis of the dichroic mirror 33, and the reflective prism 35 provided on the reflective optical axis of the mirror 34.

[0049] The tracking light receiving unit 27 has a tracking light receiving optical axis 49. The tracking light receiving unit 27 also has, in order from the light receiving side, a tracking light receiving element 51 provided on the tracking light receiving optical axis 49, the dichroic prism 41, the relay lens 42, and the light receiving and reflecting prism 43, as well as a light receiving lens 44 provided on the reflecting optical axis of the light receiving and reflecting prism 43, and a reflecting mirror 45 provided on the reflecting optical axis of the light receiving lens 44.

[0050] In this embodiment, the tracking optical axis 37, the tracking optical axis 37 reflected by the dichroic mirror 33, the tracking optical axis 37 reflected by the mirror 34, the tracking optical axis 37 reflected by the reflective prism 35, and the tracking optical axis 37 reflected by the scanning mirror 15 are collectively referred to as the tracking optical axis 37. Furthermore, the tracking light receiving optical axis 49, the tracking light receiving optical axis 49 reflected by the light receiving reflective prism 43, the tracking light receiving optical axis 49 reflected by the reflective surface 44a of the light receiving lens 44, the tracking light receiving optical axis 49 reflected by the reflective mirror 45, and the tracking light receiving optical axis 49 reflected by the scanning mirror 15 are collectively referred to as the tracking light receiving optical axis 49.

[0051] The tracking light-receiving element 51 is a CCD or CMOS sensor, which is a collection of pixels, and the position of each pixel on the tracking light-receiving element 51 can be determined. For example, each pixel has pixel coordinates with the center of the tracking light-receiving element 51 as the origin, and its position on the tracking light-receiving element 51 is determined by these pixel coordinates.

[0052] The distance measuring unit 19 is controlled by the calculation control unit 17. When pulsed distance measuring light 31 is emitted from the light-emitting element 29 onto the distance measuring optical axis 28, the distance measuring light 31 passes through the light-emitting lens 32 and the dichroic mirror 33 and is reflected by the mirror 34. The distance measuring light 31 reflected by the mirror 34 is reflected by the reflection prism 35 so that it is coaxial with the light-receiving optical axis 38 and the axis 11a. The distance measuring light 31 reflected by the reflection prism 35 is deflected at a right angle by the scanning mirror 15 and passes through the window 22 to irradiate the object to be measured. As the scanning mirror 15 rotates around the axis 11a, the distance measuring light 31 rotates (scans) perpendicular to the axis 11a and within a plane including the axis 6a.

[0053] Furthermore, since the window portion 22 is inclined at a predetermined angle with respect to the distance measuring optical axis 28, the incident of the distance measuring light 31 reflected by the window portion 22 into the receiving optical fiber 39 is prevented. In addition, the reflection position of the distance measuring light 31 by the scanning mirror 15, that is, the irradiation position of the distance measuring light 31, is the mechanical center of the surveying device 1, and this mechanical center is located on the axis 6a.

[0054] The reflected distance measuring light 46, reflected by the object being measured, passes through the window 22, is reflected at a right angle by the scanning mirror 15, and enters the distance measuring light receiving unit 25. That is, the reflected distance measuring light 46 passes around the reflective prism 35 and enters the light receiving lens 44, where it is focused and passes through the transmissive surface 44b before entering the reflective mirror 45.

[0055] Furthermore, the reflected distance measuring light 46 is reflected by the reflecting mirror 45 toward the light receiving lens 44 facing the reflecting mirror 45, and then reflected by the reflective surface 44a of the light receiving lens 44 toward the light receiving reflective prism 43 attached to the reflecting mirror 45. That is, the reflected distance measuring light 46 is reflected alternately (in the left-right direction with respect to the plane of the paper in Figure 2) along the axis 11a (the light receiving optical axis 38). In addition, after the reflected distance measuring light 46 is reflected at a right angle by the light receiving reflective prism 43, it enters the dichroic prism 41 via the relay lens 42, is reflected by the separation surface 41a, enters the light receiving end face of the light receiving optical fiber 39, and the received signal is sent to the calculation control unit 17.

[0056] The calculation control unit 17 performs distance measurement for each pulse of the distance measuring light 31 (Time of Flight) based on the time difference between the light emission timing of the light-emitting element 29 and the light reception timing of the light-receiving optical fiber 39 (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 29, 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.

[0057] Furthermore, by emitting the distance measuring light 31 at predetermined pulse intervals and rotating the mounting unit 5 and the scanning mirror 15 at a constant speed, the distance measuring light 31 is scanned in two dimensions through the cooperation of the vertical rotation of the scanning mirror 15 and the horizontal rotation of the mounting unit 5. In addition, 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 acquired. From the vertical angle data, horizontal angle data and distance measuring 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 acquired.

[0058] Furthermore, in parallel with the distance measurement operation, the tracking light 36, which has a different wavelength from the distance measurement light 31 emitted from the tracking light-emitting element 47, is slightly diverged by the tracking projection lens 48 and then deflected by the dichroic mirror 33 so as to be coaxial with the distance measurement light 31.

[0059] The tracking light 36, i.e., the reflected tracking light 52, which is irradiated onto the object to be measured coaxially with the distance measuring light 31 and reflected by the object to be measured, passes through the window portion 22, is reflected by the scanning mirror 15, and then enters the tracking light receiving portion 27. That is, the reflected tracking light 52 enters the light receiving lens 44 from around the reflecting prism 35 and passes through the transmission surface 44b.

[0060] Furthermore, the reflected tracking light 52 is reflected alternately along the axis 11a (left and right with respect to the plane of the paper in Figure 2) by the reflective mirror 45 and the reflective surface 44a, then reflected at a right angle by the light-receiving reflective prism 43, and transmitted through the relay lens 42 and the dichroic prism 41 to be received by the tracking light-receiving element 51. The reflected distance measuring light 46 and the reflected tracking light 52 are separated by the separation surface 41a. In addition, a tracking image (not shown) can be obtained by receiving the reflected tracking light 52 on the tracking light-receiving element 51.

[0061] The calculation control unit 17 calculates the positional deviation between the center of the tracking light receiving element 51 and the position where the reflected tracking light 52 is received by the tracking light receiving element 51. Based on this positional deviation, it drives the horizontal rotation motor 8 and the vertical rotation motor 13 to track the object to be measured.

[0062] As described above, in the first embodiment, the reflective surface 44a is formed at the center of the light-receiving lens 44 on the side opposite to the side where the reflective prism 35 is provided, so as to face the reflective mirror 45 and the light-receiving reflective prism 43. As a result, the reflected distance measuring light 46 and the reflected tracking light 52 that pass through the transmissive surface 44b and are reflected by the reflective mirror 45 are reflected again towards the reflective mirror 45 by the reflective surface 44a.

[0063] In other words, the optical path length of the reflected distance measuring light 46 and the reflected tracking light 52 is ensured by reflecting the reflected distance measuring light 46 and the reflected tracking light 52 multiple times between the light receiving lens 44 and the reflecting mirror 45 so that they reciprocate along the light receiving optical axis 38 and the tracking light receiving optical axis 49 (the axis 11a).

[0064] Therefore, since it is not necessary to secure an optical path length equal to the focal length of the light-receiving lens 44 in the direction of the light-receiving optical axis 38 (the tracking light-receiving optical axis 49), the lengths of the distance-measuring light-receiving unit 25 and the tracking light-receiving unit 27 in the direction of the light-receiving optical axis 38 (the tracking light-receiving optical axis 49) can be shortened. As a result, the optical system of the distance-measuring unit 19 can be miniaturized, and the entire surveying device 1 can be made smaller and lighter.

[0065] Furthermore, since the reflective surface 44a is formed on a part of the light-receiving lens 44, the reflected distance-measuring light 46 and the reflected tracking light 52 can be reflected back and forth between the light-receiving lens 44 and the reflective mirror 45 without providing a separate reflective member.

[0066] Therefore, the number of parts in the distance-measuring light-receiving unit 25 and the tracking light-receiving unit 27 can be reduced, thereby lowering manufacturing costs.

[0067] Furthermore, the reflective surface 44a is provided on the back surface of the reflective prism 35, sandwiching the light-receiving lens 44, and the size (area) of the reflective surface 44a is equal to or approximately equal to the bottom area of ​​the reflective prism 35.

[0068] Therefore, since the reflective surface 44a is formed at a position where vignetting occurs in the reflected distance measuring light 46 and the reflected tracking light 52 due to the reflective prism 35, the amount of light in the reflected distance measuring light 46 and the reflected tracking light 52 does not decrease due to the reflective surface 44a, and sufficient light can be secured.

[0069] In the first embodiment, the separation surface 41a of the dichroic prism 41 reflects the reflected distance measuring light 46 within a plane including the axis 6a and the axis 11a, but the direction of reflection is not limited to this. For example, the members of the distance measuring light receiving unit 25 may be arranged in three dimensions, and the reflected distance measuring light 46 may be reflected in a direction perpendicular to the plane.

[0070] Furthermore, in the first embodiment, the receiving optical fiber 39 is provided on the reflective side of the separation surface 41a and the tracking light receiving element 51 is provided on the transmissive side. However, the tracking light receiving element 51 may be provided on the reflective side and the receiving optical fiber 39 on the transmissive side.

[0071] Next, a second embodiment of the present invention will be described in Figure 3. In Figure 3, components equivalent to those in Figure 2 are denoted by the same reference numerals, and their descriptions are omitted.

[0072] In the second embodiment, the distance measuring light receiving unit 25 and the tracking light receiving unit 27 are provided as a light-receiving and reflecting prism joined to the center of the reflecting mirror 45, and a dichroic prism 53 is provided. The dichroic prism 53 is constructed by joining a square prism 53b and a triangular prism 53c, both having a trapezoidal cross-section, and the joining surface is a separation surface 53a on which a dichroic film is deposited. The separation surface 53a has optical properties that reflect the reflected distance measuring light 46 toward the receiving optical fiber 39 at a right angle or approximately right angle, and transmit the reflected tracking light 52. That is, the separation surface 53a functions as a separation surface that separates the reflected distance measuring light 46 and the reflected tracking light 52.

[0073] Furthermore, the reflective mirror 54, which serves as the first reflective element, is, for example, a glass plate with a reflective film formed on the surface facing the light-receiving lens 44. This reflective film is formed on the portion other than the area where the dichroic prism 53 is attached.

[0074] Furthermore, in the second embodiment, the relay lens 42 (see Figure 2) and the dichroic prism 41 (see Figure 2) are not provided, and the receiving optical fiber 39 is arranged such that its receiving end face is located at the focal point of the reflected ranging light 46. The other configurations are the same as in the first embodiment.

[0075] In the second embodiment as well, the optical path length of the reflected distance measuring light 46 and the reflected tracking light 52 is secured by reflecting the reflected distance measuring light 46 and the reflected tracking light 52 multiple times between the light receiving lens 44 and the reflecting mirror 54 so that they reciprocate along the light receiving optical axis 38 and the tracking light receiving optical axis 49 (axis 11a).

[0076] Therefore, since it is not necessary to secure an optical path length equal to the focal length of the light-receiving lens 44 in the direction of the light-receiving optical axis 38 (the tracking light-receiving optical axis 49), the lengths of the distance-measuring light-receiving unit 25 and the tracking light-receiving unit 27 in the direction of the light-receiving optical axis 38 (the tracking light-receiving optical axis 49) can be shortened. As a result, the optical system of the distance-measuring unit 19 can be miniaturized, and the entire surveying device 1 can be made smaller and lighter.

[0077] Furthermore, in the second embodiment, since the reflective surface of the dichroic prism 53 is the separating surface 53a, there is no need to provide a relay lens 42 (see Figure 2) for extending the optical path length or a dichroic prism 41 (see Figure 2) for separating the reflected distance measuring light 46 and the reflected tracking light 52, thereby reducing the number of parts and lowering manufacturing costs.

[0078] Next, a third embodiment of the present invention will be described in Figure 4. In Figure 4, components equivalent to those in Figure 2 are denoted by the same reference numerals, and their descriptions are omitted.

[0079] In the third embodiment, a reflective mirror 55 is provided in place of the reflective mirror 45 (see Figure 2) in the first embodiment, and the light-receiving and reflecting prism 43 (see Figure 2) is omitted.

[0080] The reflective mirror 55 has a hole 55a formed in its center that penetrates it, and the portion other than the center is a reflective surface 55b, which functions as a first reflective part. The hole 55a is located on the light-receiving optical axis 38 and the tracking light-receiving optical axis 49 that pass through the light-receiving lens 44, and has a diameter through which the reflected distance-measuring light 46 and the reflected tracking light 52 reflected sequentially by the reflective surface 55b and the reflective surface 44a can pass.

[0081] Furthermore, a relay lens 42, a dichroic prism 41, and a tracking light-receiving element 51 are provided on the light-receiving optical axis 38 and the tracking light-receiving optical axis 49 that pass through the hole 55a, and a light-receiving optical fiber 39 is provided on the reflective optical axis of the separation surface 41a of the dichroic prism 41. The other configurations are the same as in the first embodiment.

[0082] In the third embodiment as well, the optical path length of the reflected distance measuring light 46 and the reflected tracking light 52 is secured by causing the reflected distance measuring light 46 and the reflected tracking light 52 to be reflected back and forth multiple times between the light receiving optical axis 38 and the tracking light receiving optical axis 49 between the light receiving lens 44 and the reflecting mirror 55.

[0083] Therefore, the length of the distance measuring light receiving unit 25 and the tracking light receiving unit 27 in the direction of the light receiving optical axis 38 (the tracking light receiving optical axis 49) can be shortened, which allows for miniaturization of the optical system of the distance measuring unit 19, and thus miniaturization and weight reduction of the entire surveying device 1.

[0084] Furthermore, since there is no need for a light-receiving and reflecting prism 43 (see Figure 2) to further deflect the reflected distance measuring light 46 and the reflected tracking light 52 that are sequentially reflected by the reflective surface 55b and the reflective surface 44a, the number of parts can be further reduced, and manufacturing costs can be lowered.

[0085] Next, a fourth embodiment of the present invention will be described in Figure 5. In Figure 5, components equivalent to those in Figure 2 are denoted by the same reference numerals, and their descriptions are omitted.

[0086] In the fourth embodiment, a parallel flat plate 56 is provided between the light-receiving lens 44 and the scanning mirror 15 (see Figure 2), and a reflective prism 35 is bonded to the side of the parallel flat plate 56 that faces the scanning mirror 15, i.e., the side facing the object to be measured. The other configurations are the same as in the first embodiment.

[0087] The parallel flat plate 56 is, for example, a glass plate having a predetermined thickness, and is arranged such that the incident surface and the exit surface are perpendicular to the light-receiving optical axis 38 and the tracking light-receiving optical axis 49.

[0088] In the fourth embodiment, since the reflective prism 35 is provided on the side of the parallel plane plate 56 that faces the scanning mirror 15, the distance measuring light 31 and the tracking light 36 do not enter the parallel plane plate 56, and only the reflected distance measuring light 46 and the reflected tracking light 52 enter and pass through the parallel plane plate 56.

[0089] In the fourth embodiment, since the reflective prism 35 is bonded to the parallel plane plate 56, it is not necessary to directly bond the reflective prism 35 to the light-receiving lens 44. Therefore, the constraints on manufacturing the light-receiving lens 44 can be reduced, and the light-receiving lens 44 can be easily manufactured.

[0090] Furthermore, in the fourth embodiment as well, since the reflected distance measuring light 46 and the reflected tracking light 52 are reflected back and forth multiple times between the light receiving lens 44 and the reflecting mirror 45, the length in the direction of the light receiving optical axis 38 of the distance measuring light receiving unit 25 and the tracking light receiving unit 27 can be shortened, thereby enabling miniaturization of the optical system of the distance measuring unit 19 and the entire surveying device 1.

[0091] Next, a fifth embodiment of the present invention will be described in Figure 6. In Figure 6, components equivalent to those in Figure 5 are denoted by the same reference numerals, and their descriptions are omitted.

[0092] In the fifth embodiment, the deflection optical member is a reflective prism 57, such as a triangular prism having a reflective surface inside. The reflective prism 57 is joined to the surface of the parallel plane plate 56 on the side of the light-receiving lens 44, and the incident surfaces of the distance measuring light 31 and the tracking light 36 are arranged to be perpendicular to, for example, the distance measuring optical axis 28 and the tracking optical axis 37. The other configurations are the same as in the fourth embodiment. The reflective prism 57 may be configured so that the incident surface is tilted by about 0.5° to 3° with respect to the distance measuring optical axis 28 and the tracking optical axis 37 to prevent reflected light.

[0093] In the fifth embodiment, since the reflective prism 57 is provided on the side of the parallel plane plate 56 facing the light-receiving lens 44, the distance measuring light 31 and the tracking light 36 that pass through and are reflected from the inside of the reflective prism 57 pass through the parallel plane plate 56, and the reflected distance measuring light 46 and the reflected tracking light 52 also pass through the parallel plane plate 56. In addition, the divergence angle of the distance measuring light 31 and the tracking light 36 widens slightly as they pass through the parallel plane plate 56.

[0094] In the fifth embodiment as well, the reflective prism 57 is joined to the parallel flat plate 56, and there is no need to directly join the reflective prism 57 to the light-receiving lens 44. This reduces the constraints on manufacturing the light-receiving lens 44 and makes it easier to produce the light-receiving lens 44.

[0095] Furthermore, since the reflected distance measuring light 46 and the reflected tracking light 52 are reflected back and forth multiple times between the light receiving lens 44 and the reflective mirror 45, the length in the direction of the light receiving optical axis 38 of the distance measuring light receiving unit 25 and the tracking light receiving unit 27 can be shortened, thereby enabling miniaturization of the optical system of the distance measuring unit 19 and the entire surveying device 1.

[0096] In the first to fifth embodiments, the distance measuring unit 19 has a coaxially mounted distance measuring unit and a tracking unit, and is configured to perform distance measuring and tracking in parallel. However, the distance measuring unit 19 may also be configured to have only a distance measuring unit.

[0097] For example, Figure 7(A) shows a first modified example. This first modified example is a modification of the first embodiment. In the first modified example, the receiving optical fiber 39 is positioned such that its receiving end face is located at the focal point of the reflected ranging light 46 reflected by the light-receiving reflective prism 43, and the relay lens 42, dichroic prism 41, etc., are omitted. The same effect as the first embodiment can be obtained in the first modified example as well. Furthermore, if the light-receiving reflective prism 43 in Figure 7(A) is replaced with a dichroic prism 53 (see Figure 3), it becomes a modification of the second embodiment, and the same effect as the second embodiment can be obtained.

[0098] Furthermore, Figure 7(B) shows a second modified example. This second modified example is a modification of the third embodiment. In the second modified example, the receiving optical fiber 39 is positioned such that the receiving end face of the light-receiving optical fiber 39 is located at the focusing position of the reflected ranging light 46 that has passed through the light-receiving lens 44, for example, within the hole 55a of the reflecting mirror 55, and the relay lens 42 and the dichroic prism 41 are omitted. The same effects as those of the third embodiment can be obtained in the second modified example as well.

[0099] Furthermore, Figures 8(A) and 8(B) show a third and fourth modified example, respectively. The third modified example is a modified example of the fourth embodiment, and the fourth modified example is a modified example of the fifth embodiment. In both the third and fourth modified examples, the receiving optical fiber 39 is positioned such that its receiving end face is located at the point where the reflected distance measuring light 46 reflected by the light-receiving reflection prism 43 is collected, and the relay lens 42, dichroic prism 41, etc., are omitted. The same effects as those of the fourth and fifth embodiments can be obtained in the third and fourth modified examples, respectively.

[0100] Furthermore, in the first to third embodiments and the first and second modifications, the incident surface of the light-receiving lens 44, i.e., the surface on the scanning mirror 15 side, is flat, and the reflective prism 35 is joined to this flat surface. However, the surface shape of the incident surface and the method of attaching the reflective prism 35 are not limited to these.

[0101] For example, as shown in Figure 9(A), the incident surface of the light-receiving lens 44 may be a curved surface such as an aspherical surface, an annular aspherical surface, or an axially symmetric free surface. In this case, a flat portion 44c is formed in the center of the incident surface, and the reflective prism 35 is joined to the flat portion 44c.

[0102] Alternatively, as shown in Figure 9(B), a hole 44d may be drilled in the center of the incident surface, and the reflecting prism 35 may be joined to the hole 44d.

[0103] Furthermore, the light-receiving lens 44 is not limited to the reflective prism 35. For example, as shown in Figure 9(C), a cylindrical mirror 58 may be provided as a deflection optical element.

[0104] The cylindrical mirror 58 has a hollow cylindrical portion 58a and a dichroic mirror 58b as a reflective surface, and is joined to the hole 44d. The dichroic mirror 58b has optical properties that transmit visible light and reflect near-infrared light, i.e., the distance measuring light 31 and the tracking light 36.

[0105] Furthermore, an imaging unit 59 is provided inside the cylindrical portion 58a, and the dichroic mirror 58b and the imaging unit 59 are arranged such that the imaging optical axis 61 of the imaging unit 59 coincides with the distance measuring optical axis 28 and the tracking optical axis 37 deflected by the dichroic mirror 58b. In other words, the imaging unit 59 is arranged coaxially with the distance measuring unit and the tracking unit.

[0106] By using the cylindrical mirror 58, which houses the imaging unit 59, as the deflection optical element, an image can be acquired using ambient light incident coaxially with the reflected distance measuring light 46 and the reflected tracking light 52. This allows for simultaneous performance of distance measurement, tracking, photography, and sighting.

[0107] In the first to fifth embodiments and the first to fourth modifications, the case where the light-receiving lens 44 has a focal length f = 110 mm and an objective effective diameter φ 50 mm was described. On the other hand, light-receiving lenses with other focal lengths f and objective effective diameters φ are also applicable to each embodiment and each modification, and it goes without saying that the optical design can be appropriately changed to correspond to the focal length f and objective effective diameter φ. [Explanation of Symbols]

[0108] 1 Surveying equipment 3 Surveying device body 17. Arithmetic Control Unit 19 Distance measuring unit 24 Distance measurement light emission part 25 Distance measurement light receiver 31 Ranging light 39 Receiving optical fiber 44 Light-receiving lens 45 Reflective mirror 46 Reflected ranging light

Claims

1. A measuring device comprising: a distance measuring light emission unit that emits distance measuring light onto an object to be measured; a distance measuring light receiving unit having a light receiving unit that receives reflected distance measuring light from the object to be measured; and a calculation control unit that controls the distance measuring light emission unit and calculates the distance to the object to be measured based on the result of receiving the reflected distance measuring light to the light receiving unit, wherein the distance measuring light receiving unit has a light receiving lens that focuses the reflected distance measuring light and a reflective mirror provided opposite the light receiving lens, a reflective surface is formed at the center of the surface of the light receiving lens that faces the reflective mirror, and the reflected distance measuring light that has passed through the light receiving lens is reflected back and forth between the reflective mirror and the reflective surface along the optical axis of the reflected distance measuring light.

2. The surveying device according to claim 1, further comprising a light-receiving reflective prism provided on the reflective mirror, wherein the light-receiving reflective prism is configured to deflect the reflected distance-measuring light reflected from the reflective surface at a right angle or approximately a right angle.

3. The surveying device according to claim 1, wherein the reflective mirror further has a hole formed in its center, and the reflected distance measuring light reflected from the reflective surface passes through the hole.

4. The surveying apparatus according to claim 1, further comprising a scanning mirror that rotates and illuminates the distance measuring light, a deflection optical member that deflects the distance measuring light so that it aligns with the rotation axis of the scanning mirror, and a parallel plane plate provided on the scanning mirror side of the light receiving lens, wherein the deflection optical member is joined to the surface of the parallel plane plate on the scanning mirror side.

5. The measuring device according to claim 1, further comprising a scanning mirror that rotates and illuminates the distance measuring light, a deflection optical member that deflects the distance measuring light so that it aligns with the rotation axis of the scanning mirror, and a parallel plane plate provided on the scanning mirror side of the light receiving lens, wherein the deflection optical member is bonded to the surface of the parallel plane plate on the light receiving lens side.

6. The surveying apparatus according to claim 2, further comprising a tracking light emission unit that emits tracking light coaxially with the distance measuring light to the object to be measured, and a tracking light receiving unit having a tracking light receiving element that receives reflected tracking light reflected coaxially from the object to be measured, wherein a dichroic prism having a separation surface that separates the reflected distance measuring light and the reflected tracking light is arranged on the reflected light axis of the light receiving and reflecting prism.

7. The surveying apparatus according to claim 2, further comprising a tracking light emission unit that emits tracking light coaxially with the distance measuring light to the object to be measured, and a tracking light receiving unit having a tracking light receiving element that receives reflected tracking light reflected coaxially from the object to be measured, wherein the light receiving and reflecting prism is a dichroic prism having a separation surface that separates the reflected distance measuring light and the reflected tracking light.

8. The surveying apparatus according to claim 3, further comprising a tracking light emission unit that emits tracking light coaxially with the distance measuring light to the object to be measured, and a tracking light receiving unit having a tracking light receiving element that receives reflected tracking light reflected coaxially from the object to be measured, wherein a dichroic prism having a separating surface that separates the reflected distance measuring light and the reflected tracking light is arranged on the optical axis of the reflected distance measuring light and the reflected tracking light passing through the hole.

9. The surveying apparatus according to claim 1, further comprising a scanning mirror that rotates and irradiates the distance measuring light, and a deflecting optical member that deflects the distance measuring light so that it aligns with the rotation axis of the scanning mirror, wherein a flat portion is formed in the center of the incident surface of the light receiving lens, and the deflecting optical member is joined to the flat portion.

10. The measuring device according to claim 1, further comprising a scanning mirror that rotates and illuminates the distance measuring light, and a deflecting optical member that deflects the distance measuring light so that it aligns with the rotation axis of the scanning mirror, wherein a hole is formed in the center of the incident surface of the light receiving lens, and the deflecting optical member is joined to the hole.

11. The measuring device according to claim 10, wherein the deflection optical member comprises a cylindrical portion having an imaging unit having an imaging optical axis coaxial with the distance measuring light, and a cylindrical mirror having a dichroic mirror that reflects the distance measuring light and transmits visible light.

Images