Reflector and target device

Abstract

The present invention is equipped with a plurality of reflector elements (1). Each of the reflector elements comprises a deflecting optical member (2) that is disposed on an incident light axis (4) of measurement light and reflects the measurement light and a retroreflector (3) that is disposed on a reflected light axis (4') of the deflecting optical member and retroreflects the measurement light. Each of the reflector elements is configured so as to form a virtual image of the optical center of the reflector element on an extension of the incident light axis. The plurality of reflector elements are combined so that the positions of the virtual images coincide or approximately coincide.

Description

Reflector and Target Device

[0001] The present disclosure relates to a reflector used as a target in measurement and a target device including the reflector.

[0002] When performing optical distance measurement with a measuring device, a reflector as a target is provided at the measurement point.

[0003] The reflector includes a retroreflector, which retroreflects the measurement light. The measuring device receives the reflected measurement light and performs distance measurement based on the time difference between the emission timing of the measurement light and the reception timing of the reflected measurement light and the speed of light, or receives the reflected measurement light and performs angle measurement or distance and angle measurement. Further, in a measuring device having a tracking function, the reflected measurement light is received to track the reflector. Examples of the retroreflector include a prism having retroreflectivity such as a corner cube prism or one composed of three mirrors. Note that the measurement light includes the distance measurement light when measuring distance, the angle measurement light when measuring an angle, and the tracking light when tracking a measurement target.

[0004] For example, in the case of a corner cube prism as the retroreflector, the optical center, which is the measurement reference point, exists inside the corner cube prism. Also, in order to accurately measure the measurement point without directly facing the reflector with the surveying instrument, it is necessary to install the reflector such that the position of the optical center of the corner cube prism coincides with the measurement point.

[0005] Usually, the reflector is held by a holding device, which has a housing of the reflector, a pole to which the housing is attached, and a stake installed at the measurement point.

[0006] The corner cube prism has an optical center as the measurement reference point, and the optical center is inside the corner cube prism. Therefore, when the stake is provided at the lower end of the pole, the optical center is offset from the axis of the pole (see Patent Document 2). In this case, an error due to the offset occurs when the reflector is not directly facing the measuring device.

[0007] Furthermore, if the tip is positioned on a vertical line passing through the optical center, the tip and the pole must be separate components (see Patent Documents 3 and 4). In this case, the support structure of the reflector becomes complex.

[0008] Japanese Patent Publication No. 2007-187857, Japanese Utility Model Publication No. 59-34313, Japanese Patent Publication No. 2018-21867, Japanese Utility Model Publication No. 6-4614, Japanese Patent No. 3551266

[0009] This disclosure provides a reflector and target device that, when the reflector is installed at a measurement point, minimizes errors in distance and angle measurement at the measurement reference point, and further enables retroreflection of measurement light from a wide range.

[0010] This disclosure relates to a reflector comprising a plurality of reflector elements, each reflector element comprising a deflection optical member provided on the incident optical axis of the measurement light and reflecting the measurement light, and a retroreflector provided on the reflected optical axis of the deflection optical member and retroreflecting the measurement light, wherein a virtual image of the optical center of the reflector element is formed on the extension of the incident optical axis, and the plurality of reflector elements are combined such that the positions of the virtual images coincide or substantially coincide.

[0011] According to this disclosure, the measurement reference point of the reflector can be set to the virtual image position, the measurement reference position can be set to the measurement point without offset, and furthermore, measurement light from a wide range can be retroreflected.

[0012] Figure 1 is a side view of a reflector element according to this embodiment. Figure 2 is a side view of a reflector element according to this embodiment. Figure 3 is a top view of a reflector according to the first embodiment. Figure 4 is a top view of a reflector according to the second embodiment. Figure 5 is a top view of a reflector according to a modified example of the second embodiment. Figure 6(A) is a perspective view of a reflector according to the third embodiment, and Figure 6(B) is a side view of the reflector element of the reflector. Figure 7(A) is a perspective view of a reflector according to the fourth embodiment, and Figure 7(B) is a side view of the reflector element of the reflector. Figure 8(A) is a perspective view of a reflector according to the fifth embodiment, Figure 8(B) is a side view of the reflector, and Figure 8(C) is a side view of the reflector element of the reflector. Figure 9(A) is a perspective view of a reflector according to the sixth embodiment, Figure 9(B) is a side view of the reflector, and Figure 9(C) is a side view of the reflector element of the reflector. Figure 10(A) is a perspective view of a reflector according to the seventh embodiment, Figure 10(B) is a side view of the reflector, and Figure 10(C) is a side view of the reflector element of the reflector. Figure 11(A) is a perspective view of a reflector according to the eighth embodiment, Figure 11(B) is a side view of the reflector, and Figure 11(C) is a side view of the reflector element of the reflector. Figure 12(A) is a perspective view of a reflector according to the ninth embodiment, Figure 12(B) is a side view of the reflector, and Figure 12(C) is a side view of the reflector element of the reflector. Figure 13 is an explanatory diagram of measurement using the target device of this embodiment.

[0013] The embodiments of this disclosure will be described below with reference to the drawings.

[0014] Figures 1 and 2 show the basic configuration diagrams of the reflector relating to this disclosure.

[0015] In Figure 1, 1 represents a reflector element, which includes a reflective triangular prism 2 as a deflection optical element and a corner cube prism 3 as a retroreflector (retroreflector). In the following description, the retroreflector is assumed to be a corner cube prism with three orthogonal reflective surfaces (angles of 90°, 90°, 90°). On the other hand, any prism other than a corner cube prism, or even a mirror, may be used as long as it has retroreflectivity.

[0016] In addition to corner cube prisms, prisms that can be used as retroreflectors include prisms with angles formed by three reflective surfaces of 90°90°90° / n (natural number) and 90°60°45°. Furthermore, mirrors that can be used as retroreflectors may be three mirrors configured with angles formed by three reflective surfaces similar to those of the above-mentioned prisms, or they may be the mirrors shown in Patent Document 5.

[0017] The reflective triangular prism 2 is positioned on the incident optical axis 4, and the incident optical axis 4 enters the reflective triangular prism 2 from the incident surface 2b, is reflected and deflected by the inner reflective surface 2a. The deflected reflected optical axis 4' is ejected from the ejection surface 2c. The corner cube prism 3 is positioned on the reflected optical axis 4' of the ejection surface 2c. The optical center O of the corner cube prism 3, which serves as a measurement reference point, is located on the reflected optical axis 4'. Note that reflection occurring inside the prism (optical element) is called internal reflection, and the reflective surface is called the internal reflective surface. By positioning the corner cube prism 3 on the reflective triangular prism 2, the optical center O'' of the composite including the reflective triangular prism 2 and the corner cube prism 3 shifts towards the inner reflective surface 2a. Note that the composite represents a reflector element, and the optical center O'' means the optical center of the reflector element.

[0018] As the incident optical axis 4 is deflected by internal reflection on the internal reflective surface 2a, a virtual image O' of the optical center O'' is formed at a position on the extension of the incident optical axis 4, that is, at a position away from the reflective triangular prism 2 and the corner cube prism 3. The virtual image O' and the optical center O'' are symmetrical with respect to the internal reflective surface 2a, and if R is the point of reflection deflection of the incident optical axis 4 on the internal reflective surface 2a, then the distance between R and the optical center O'' is equal to the distance between R and the virtual image O', meaning that the virtual image O' is equivalent to the position of the measurement reference point. When measuring the reflector element 1 as the object to be measured, if the position of the virtual image O' is set at the measurement point, the measurement point can be measured without error.

[0019] Furthermore, the corner cube prism 3 may be provided in close contact with the ejection surface 2c, or it may be provided in an optically non-contact manner.

[0020] Figure 2 shows another reflector element 1'. In this reflector element 1', a mirror 5 is used as the deflection optical member.

[0021] In the reflector element 1', the incident optical axis 4 is reflected and deflected by the reflective surface 5a, and a virtual image O' of the optical center O is formed on the extension of the incident optical axis 4. The virtual image O' and the optical center O are symmetrical with respect to the reflective surface 5a, and the distance between the reflection deflection point R on the reflective surface 5a and the optical center O is equal to the distance between the reflection deflection point R and the virtual image O', so that the position of the virtual image O' is equivalent to the position of the measurement reference point. Note that reflection outside the optical member (in the air) is called external reflection, and the reflective surface is called the external reflection surface. Note that in the reflector element 1', the optical center O is the optical center of the reflector element 1'.

[0022] The reflector according to the first embodiment will be described with reference to Figure 3. Figure 3 shows a top view of the reflector, and in Figure 3, components equivalent to those shown in Figure 1 are given the same reference numerals and their descriptions are omitted.

[0023] In the reflector 6 of the first embodiment, two sets of the reflector elements 1 (reflector elements 1a and 1b) are arranged symmetrically in the same plane, and the virtual image O' positions of the two sets of reflector elements 1a and 1b are arranged to coincide. The agreement of the virtual image O' positions of the two sets of reflector elements 1a and 1b includes cases where they coincide exactly, or cases where they coincide approximately to the extent that the measurement error is within an acceptable range.

[0024] By configuring the reflector 6 with two sets of reflector elements 1a and 1b, measurement light incident with a wide field of view in the horizontal direction can be retroreflected. In the first embodiment shown in the figure, the field of view in the horizontal direction is approximately 140°, and the field of view in the vertical direction is approximately 70°.

[0025] Furthermore, an indicator unit is provided at the position of the virtual image O' to indicate a measurement point, and the reflector 6 is held in the indicator unit.

[0026] A pole 8 is exemplified as the indicator. The pole 8 is provided so as to extend vertically (perpendicular to the plane of the paper in Figure 3). A tip is provided at the lower end of the pole 8, and the tip has a tip capable of indicating a measurement point, and the shape of the tip is either pointed or spherical. The axis 7 of the pole 8 passes through the tip of the tip, and the position of the virtual image O' is set on the axis 7.

[0027] The pole 8 functions as a support member for the reflector 6 and also as an indicator for indicating the measurement point.

[0028] Therefore, by placing the tip of the pole 8 at the measurement point and supporting the pole 8 vertically, the reflector 6 retroreflects the measurement light incident from within a horizontal range of 140°, allowing the measurement point to be measured without error.

[0029] Furthermore, by making the reflector 6 movable in the axial direction relative to the pole 8 and fixable at any position, the height of the reflector 6 can be adjusted.

[0030] Figure 4 shows a reflector 10 according to the second embodiment, and is a plan view of the reflector 10. In Figure 4, components equivalent to those shown in Figure 2 are denoted by the same reference numerals, and their descriptions are omitted.

[0031] In the reflector 10 of the second embodiment, two sets of reflector elements 1a' and 1b' equivalent to the reflector element 1' are arranged symmetrically in the same plane, and the positions of the virtual images O' of the two sets of reflector elements 1a' and 1b' are configured to coincide or substantially coincide.

[0032] The two sets of reflector elements 1a' and 1b' are the same as those of reflector element 1' shown in Figure 2, but with the mirror 5 replaced by a reflective prism 11. The reflective prism 11 is an isosceles triangular prism having two outer reflective surfaces 11a and 11b. These outer reflective surfaces 11a and 11b correspond to the reflective surface 5a of the reflector element 1'. The virtual image O' is formed outside the reflective prism 11.

[0033] In the second embodiment as well, an indicator unit for indicating a measurement point is provided at the position of the virtual image O', and the reflector 10 is held by the indicator unit. Furthermore, by making the indicator unit the pole 8, the height position of the reflector 10 can be adjusted.

[0034] Figure 5 shows a modified reflector 12 of the second embodiment. In Figure 5, components equivalent to those shown in Figure 4 are denoted by the same reference numerals, and their descriptions are omitted.

[0035] In this modified version of the reflector 12, the indicator section provided on the reflector 12 has been changed.

[0036] In Figure 5, 13 indicates a housing that contains the reflective prism 11 and the corner cube prism 3 (reflector elements 1a', 1b').

[0037] The housing 13 is open at the front, and an indicator portion 14 is provided on the rear wall 13a of the housing 13. The indicator portion 14 is a rod-shaped probe that extends to the rear, with a pointed tip, and the position of the tip is such that it coincides with or substantially coincides with the position of the virtual image O'.

[0038] In this modified example, the reflector 12 and the indicator unit 14 are integrated, making them easy to handle. Furthermore, the reflector 12 can be directly placed at the measurement point via the indicator unit 14, improving work efficiency.

[0039] Furthermore, the shape of the rear wall 13a may be changed to form an indicator portion that protrudes to the rear.

[0040] Furthermore, in the second embodiment and modifications thereof, two mirrors having external reflective surfaces 11a and 11b may be used instead of the reflective prism 11.

[0041] Figure 6(A) shows a third embodiment. Note that the support portion for the optical element is omitted from the illustration in Figure 6(A).

[0042] The third embodiment shows a reflector 16 that can retroreflect measurement light incident from all directions (360°).

[0043] Figure 6(B) shows the reflector element 16a in the third embodiment.

[0044] The reflector element 16a has the same configuration as the reflector element 1′ shown in FIG. 2. The reflector element 16a includes a mirror 17 having an outer surface reflecting surface 17a as a deflection optical member, and a corner cube prism 18 provided opposite to the outer surface reflecting surface 17a.

[0045] The corner cube prism 18 is provided on the reflected optical axis 4′ deflected vertically upward by the outer surface reflecting surface 17a, and the optical center O of the corner cube prism 18 is located on the reflected optical axis 4′. A virtual image O′ is formed on the extension of the incident optical axis 4, and the virtual image O′ serves as the measurement reference point.

[0046] Also, the distance between the reflection deflection point R and the optical center O is equal to the distance between the reflection deflection point R and the virtual image O′, and the position of the virtual image O′ is located more toward the center side (right side of the mirror 在图6(B)中) than the inner end (right end in FIG. 6(B)) of the mirror 17, and the position of the corner cube prism 18 is set accordingly.

[0047] The reflector 16 shown in FIG. 6(A) is configured such that six sets of the reflector elements 16a are arranged in the same plane at 60° intervals around the virtual image O′. In this case, the shape of the reflector element 16a is trapezoidal, and the angle of the apex angle of the trapezoid projected onto the plane is 360° / 6 = 60°.

[0048] The measurement reference points of all the reflector elements 16a coincide or substantially coincide with the position of the virtual image O′. Also, since the virtual image O′ is formed at a position outside the mirror 17 (see FIG. 6(B)), a space 19 is formed in the central portion of the reflector 16.

[0049] In the reflector 16, a pole 8 is provided in the space 19, and the reflector 16 is supported by the pole 8. The pole 8 is perpendicular to the plane on which the reflector element 16a is provided, and the virtual image O′ of each reflector element 16a is formed at a point on the axis 7 of the pole 8.

[0050] Furthermore, it goes without saying that the reflector 16 may be made movable in the axial direction relative to the pole 8, and may also be fixed at any position.

[0051] The target device is constructed by inserting the pole 8 through the reflector 16 and supporting the reflector 16 on the pole 8. Furthermore, by integrating the reflector elements 16a, the reflector 16 takes the shape of a truncated octagon and becomes self-supporting. Therefore, the pole 8 can be omitted, and the reflector 16 can be installed at the measurement point on its own and function as a target device. When the reflector 16 is used on its own, the space 19 may be omitted, and the virtual image O' may be aligned with the inner end of the mirror 17.

[0052] Furthermore, although the above description describes the reflector 16 as being composed of six sets of reflector elements 16a, it is also possible to compose it with five sets of reflector elements 16a spaced at 72° intervals, or even with n sets of reflector elements 16a spaced at 360° / n intervals.

[0053] As described above, since the measurement reference points of all reflector elements 16a coincide with or substantially coincide with the position of the virtual image O', the errors in distance measurement and angle measurement when the reflector 16 is used as a full-circumference prism are extremely small.

[0054] Figure 7(A) shows a reflector 21 according to the fourth embodiment. The reflector 21 is composed of two sets of upper and lower reflector units 22a and 22b.

[0055] Furthermore, Figure 7(B) shows the reflector elements 21a that constitute each reflector unit 22a, 22b, and is a side view of the reflector element 21a.

[0056] The reflector element 21a has a similar configuration to the reflector element 16a shown in Figure 6(B). The reflector element 21a consists of a mirror 23 having a reflective surface 23a as a deflection optical member, and a corner cube prism 24 provided opposite the reflective surface 23a. A virtual image O' of the optical center O of the corner cube prism 24 is formed on the extension of the incident optical axis 4 and further towards the center than the inner end of the mirror 23. In addition, the tip (outer end) of the mirror 23 is formed so that its lower surface is horizontal.

[0057] The reflector element 21a is arranged in six sets in the same plane at 60° intervals around the virtual image O', thereby forming the reflector unit 22a.

[0058] Furthermore, the reflector unit 22b is constructed by arranging six sets of the reflector element 21b, obtained by inverting the reflector element 21a vertically, in the same plane at 60° intervals with respect to the virtual image O'.

[0059] The reflector 21 is constructed by combining the reflector unit 22a and the reflector unit 22b in a way that is vertically symmetrical.

[0060] Similar to the reflector 16, a space is formed in the center of the reflector 21, and a pole 8 is provided in this space, with the axis 7 of the pole 8 coinciding with or substantially coinciding with the position of the virtual image O'.

[0061] In the fourth embodiment as well, the pole 8 functions as a support member for supporting the reflector 21 and as an indicator unit for indicating the measurement point.

[0062] Furthermore, in the fourth embodiment as well, the reflector units 22a and 22b are constructed by combining n sets of the reflector elements 21a and 21b at 360° / n intervals. The number of sets of reflector elements 21a and 21b that make up the reflector units 22a and 22b is appropriately selected considering the measurement environment, the required retroreflective performance, etc.

[0063] The reflector 21 retroreflects the measurement light incident from all directions (360°), and the virtual image O' is the measurement reference point. When the reflector 21 is used as a full-circumference prism, the errors in distance measurement and angle measurement become extremely small.

[0064] In the third embodiment described above, six mirrors 17 were shown as the deflection optical element, but it may also be a single reflective prism that forms six reflective surfaces equivalent to the collection of six mirrors 17. Similarly, in the fourth embodiment, the deflection optical element may also be a single reflective prism that forms twelve reflective surfaces equivalent to the reflective surfaces of twelve mirrors 23.

[0065] Figures 8(A) and 8(B) show a reflector 26 according to the fifth embodiment, where Figure 8(A) is a perspective view of the reflector 26 from above, Figure 8(B) is a side view, and Figure 8(C) shows the reflector element 26a.

[0066] The reflector 26 is composed of six sets of reflector elements 26a, each of which consists of a reflective prism 27 and a corner cube prism 28.

[0067] The reflective prism 27 has a vertical rectangular outer surface (incident surface 27a), a horizontal trapezoidal upper surface (exit surface 27b), and a bottom surface (inner reflective surface 27c) inclined at 45° to the horizontal, and its planar shape is wedge-shaped, with the central angle (vertex angle) of the wedge shape being 360° / 6 = 60°. The angle formed by the incident surface 27a and the inner reflective surface 27c (lower end vertex angle α) is 45°.

[0068] The corner cube prism 28 is provided on the central side of the injection surface 27b. The injection surface 27b and the corner cube prism 28 are provided by an appropriate method such as joining them with an adhesive, providing them in close contact, or leaving a gap between them.

[0069] The incident optical axis 4 of the measurement light is incident on the inner reflective surface 27c at an incident angle of 45°, and is internally reflected by the inner reflective surface 27c and deflected at a right angle. The reflected optical axis 4' is set to pass through the optical center O'' of the reflector element 26a. Furthermore, a virtual image O' of the optical center O'' is formed on the extension of the incident optical axis 4. The position of the virtual image O' is set to be located further towards the center than the inner surface 27d of the reflecting prism 27.

[0070] The six sets of reflector elements 26a are arranged so that their virtual images O' coincide or nearly coincide, with the virtual image O' as the center. By combining the six sets of reflector elements 26a, the reflector 26 is formed in a hexagonal prism shape, with a space 29 formed in the center of the reflector 26. The center of the reflector 26 is the position of the virtual image O', i.e., the measurement reference point.

[0071] Since the reflector 26 is self-supporting, it may be installed with its center aligned with or approximately aligned with the measurement point, or a pole 8 may be inserted through the space 29, the reflector 26 may be supported by the pole 8, and the reflector 26 may be installed at the measurement point via the pole 8.

[0072] Therefore, the reflector 26 functions as a target device on its own, and also functions as part of a target device when attached to the pole 8 as a reflector. Furthermore, when the reflector 26 is used as a target device on its own, the space 29 in the center of the reflector 26 may be not formed and the two components may be integrated, so that the position of the virtual image O' coincides with the inner surface 27d (inner end) of the reflective prism 27.

[0073] The reflector 26 retroreflects measurement light from all directions and functions as an all-around prism. Furthermore, the reflector 26 allows the measurement reference point to be positioned vertically above the measurement point, and since there is no offset relative to the measurement point, measurement can be performed without error.

[0074] In addition, although the above description described a case in which the reflector 26 is composed of six sets of reflector elements 26a, it goes without saying that it may also be composed of n sets of reflector elements 26a with a central angle of 360° / n.

[0075] Figures 9(A) and 9(B) show a reflector 31 according to the sixth embodiment, where Figure 9(A) is a perspective view from above, Figure 9(B) is a side view, and Figure 9(C) shows the reflector element 31a. In Figures 9(A), 9(B), and 9(C), components equivalent to those shown in Figures 8(A), 8(B), and 8(C) are denoted by the same reference numerals and their descriptions are omitted.

[0076] In the sixth embodiment, the reflector 31 is composed of five sets of reflector elements 31a. The reflector elements 31a have the same configuration and shape as in the fifth embodiment, and the reflector elements 31a are composed of a reflective prism 32 and a corner cube prism 33.

[0077] In the reflector element 31a, the lower end vertex angle α is <45°, the incident optical axis 4 entering from the incident surface 32a is deflected by the inner reflective surface 32c, the deflection angle of the reflected optical axis 4' is <90°, and the emission surface 32b is perpendicular to the reflected optical axis 4'. By making the deflection angle less than 90°, the formation position of the virtual image O' can be moved away from the inner reflective surface 32c. As shown in the figure, the virtual image O' is formed on the central side of the inner surface 32d of the reflecting prism 32.

[0078] In this configuration, the reflected light axis 4' passes through the front end of the emission surface 32b, and the position where the corner cube prism 33 is provided is also on the front end of the emission surface 32b (the outer circumference of the reflector 31). Therefore, the radial size of the reflector element 31a can be reduced, and the reflector 31 can be miniaturized.

[0079] In the sixth embodiment as well, the reflector 31 functions as a full-circumference prism, and by inserting a pole 8 through its center and supporting the reflector 31 on the pole 8, it can be configured as a target device. Furthermore, it goes without saying that the virtual image O' is located on the axis 7 of the pole 8. When the pole 8 is in a vertical position, i.e., the reflector 31 is in a vertical position, the measurement reference point is located vertically above the measurement point, and there is no offset with respect to the measurement point, so measurement can be performed without error.

[0080] Furthermore, since the reflector 31 is self-supporting, the pole 8 can be omitted, and the reflector 31 can function as a target device on its own. In this case, the central space can be omitted, and the position of the virtual image O' can be aligned with the inner surface 32d (inner end) of the reflective prism 32.

[0081] Figures 10(A) and 10(B) show a reflector 35 according to the seventh embodiment, where Figure 10(A) is a perspective view of the reflector 35 from above, and Figure 10(B) is a side view.

[0082] The reflector 35 is composed of two sets of upper and lower reflector units: an upper reflector unit 36a and a lower reflector unit 36b.

[0083] Figure 10(C) shows the reflector elements 35a that make up the upper reflector unit 36a and the lower reflector unit 36b.

[0084] Since the upper reflector unit 36a and the lower reflector unit 36b have a vertically symmetrical configuration, the upper reflector unit 36a will be described first.

[0085] In the seventh embodiment, the upper reflector unit 36a is composed of five sets of reflector elements 35a. The reflector elements 35a are composed of a reflective prism 37 and a corner cube prism 38.

[0086] The reflective prism 37 has a trapezoidal shape, with its bottom surface 37b, which is the inner reflective surface, sloping upwards towards the center, and the angle between the incident surface 37a and the bottom surface 37b is acute. A corner cube prism 38 is provided on the top surface 37c.

[0087] The incident optical axis 4 is deflected by internal reflection from the bottom surface 37b, and the deflection angle is less than 90°. The reflected optical axis 4' deflected by the bottom surface 37b is configured to pass through the optical center O'' of the reflector element 35a.

[0088] The virtual image O' of the optical center O'' is formed on the extension of the incident optical axis 4, and by setting the deflection angle of the reflected optical axis 4' to less than 90°, the position of the virtual image O' becomes further away from the bottom surface 37b (inner reflective surface). In addition, the virtual image O' is formed on the central side of the inner surface 37d of the reflecting prism 37.

[0089] The upper reflector unit 36a is constructed by arranging five sets of the reflector elements 35a at 72° intervals around the virtual image O'.

[0090] Furthermore, the lower reflector unit 36b is constructed by arranging five sets of the reflector element 35b, obtained by inverting the reflector element 35a vertically, at 72° intervals around the virtual image O'.

[0091] The reflector 35 is constructed by combining the upper reflector unit 36a and the lower reflector unit 36b in a way that is symmetrical vertically.

[0092] By positioning the virtual image O' further away from the bottom surface 37b (internal reflective surface), a space can be formed in the center of the reflector 35, through which the pole 8 is inserted and the reflector 35 is supported by the pole 8.

[0093] The reflector 35 is supported by the pole 8 to form a target device, and it goes without saying that the position of the virtual image O' (position of the measurement reference point) is located on the axis 7 of the pole 8.

[0094] The reflector 35 allows the measurement reference point to be set vertically above the measurement point, and when the reflector 35 is used as a full-circumference prism, the errors in distance measurement and angle measurement become extremely small.

[0095] Furthermore, it goes without saying that the upper reflector unit 36a and the lower reflector unit 36b are constructed by combining n sets of the reflector elements 35a at 360° / n intervals.

[0096] Figures 11(A) and 11(B) show a reflector 39 according to the eighth embodiment, where Figure 11(A) is a perspective view of the reflector 39 from above, and Figure 11(B) is a side view.

[0097] Figure 11(C) shows the reflector elements 39a that constitute the reflector 39. In the eighth embodiment, the reflector 39 is composed of four sets of the reflector elements 39a.

[0098] First, the reflector element 39a will be described.

[0099] The reflector element 39a is composed of a reflective prism 40 and a corner cube prism 41.

[0100] The planar shape of the reflective prism 40 is triangular with a central angle (vertex angle) of 90°, and the vertex is cut off. The surface including the base of the triangular shape (outer surface 40a) is vertical, and the angle between the inner reflective surface 40b, which is opposite the outer surface 40a, and the outer surface 40a is <45°. Therefore, the angle between the incident optical axis 4 and the reflected optical axis 4' deflected by the inner reflective surface 40b is <90°.

[0101] The upper surface 40c of the reflective prism 40 slopes upward toward the center, and the reflected optical axis 4' is perpendicular to the upper surface 40c. The corner cube prism 41 is provided on the upper surface 40c, and the optical center O'' of the reflector element 39a is set to be located on the reflected optical axis 4'. Furthermore, the virtual image O'' of the optical center O'' is formed on the extension of the incident optical axis 4, further towards the center than the inner end (inner surface 40d) of the reflective prism 40.

[0102] The reflector 39 is formed by combining the four sets of reflector elements 39a, and the virtual images O' of the four sets of reflector elements 39a coincide at one point or substantially coincide.

[0103] Since the top of the reflective prism 40 is cut off, a space 42 is formed in the center of the reflector 39, and the virtual image O' is located in the space 42.

[0104] The reflector 39 is self-supporting and can be installed at the measurement point independently. Therefore, the reflector 39 functions as a target device. Furthermore, by inserting a pole 8 through the space 42 and attaching the reflector 39 to the pole 8, it can be made into a target device with a pole 8. It goes without saying that the virtual image O' is located on the axis 7 of the pole 8. Also, if the reflector 39 is self-supporting, the space 42 may be omitted and the position of the virtual image may be made to coincide with the inner end of the reflective prism.

[0105] Figures 12(A) and 12(B) show a reflector 43 according to the ninth embodiment, where Figure 12(A) is a perspective view of the reflector 43 from above, and Figure 12(B) is a side view.

[0106] Figure 12(C) shows the reflector element 43a that constitutes the reflector 43.

[0107] The reflector 43 is composed of two sets of upper and lower reflector units: an upper reflector unit 44a and a lower reflector unit 44b.

[0108] Since the upper reflector unit 44a and the lower reflector unit 44b have a vertically symmetrical configuration, the upper reflector unit 44a will be described first.

[0109] Furthermore, the reflector 43 in the ninth embodiment has the same configuration as the reflector 35 described in the seventh embodiment. In the seventh embodiment, the reflector units 36a and 36b were each composed of five sets of reflector elements 35a, but in the ninth embodiment, the upper reflector unit 44a and the lower reflector unit 44b are each composed of four sets of reflector elements 43a.

[0110] Furthermore, the reflector element 35a and the reflector element 43a have substantially the same configuration, and in this embodiment, the upper reflector unit 44a is composed of four sets of reflector elements 43a arranged at 360° / 4 intervals. In the figure, 45 represents a reflective prism and 46 represents a corner cube prism.

[0111] The reflector 43 functions as a full-circumference prism, and when the reflector 43 is in a vertical position, the measurement reference point is located vertically above the measurement point, and there is no offset relative to the measurement point, so measurement can be performed without error.

[0112] Furthermore, since this embodiment has an upper reflector unit 44a and a lower reflector unit 44b, it is possible to retroreflect measurement light from a wide range of vertical directions. In the ninth embodiment, the number of prisms is smaller than in the seventh embodiment, and it can be manufactured at a lower cost.

[0113] Furthermore, although the above embodiments are configured to retroreflect measurement light from all directions, the reflector may also be configured to retroreflect measurement light within a predetermined range of field angles. In the above embodiments, the retroreflection field angle was set to 360°, but it is also possible to accommodate cases where the retroreflection field angle is an arbitrary W°. That is, the reflector may be composed of n sets of reflector elements at W° / n intervals. Note that W° includes 360°. Alternatively, in the above embodiments, the reflector may be configured by omitting one or two reflector elements.

[0114] Figure 13 shows a measurement using the target device 51 according to this disclosure.

[0115] In Figure 13, the target device 51 is shown as a case where a reflector 52 is provided on the pole 8. Note that the reflector 52 includes all the reflectors described above. In Figure 13, 53 indicates a measuring device.

[0116] The measuring device 53 is installed at a known point, and the target device 51 is installed at the measurement point P. The reflector 52 is pointed towards the measuring device 53, and the measurement is performed with the pole 8 in a vertical position. At this time, even if the reflector 52 is not precisely facing the measuring device 53 and the measurement light is incident on the reflector 52 at an angle, the virtual image O' (measurement reference point) is located on the axis of the pole 8, that is, the measurement reference point is vertically above the measurement point P, so no measurement error occurs.

[0117] Furthermore, when the reflector 52 is used as a full-circumference prism, the target device 51 can be measured from multiple points, and no errors occur due to differences in measurement direction.

[0118] In the above embodiment, the measurement reference position of the reflector can be set to the virtual image position, the measurement reference position can be installed without offsetting it to the measurement point, and measurement light from a wide range can be retroreflected.

[0119] The embodiments and modifications of the present disclosure have been described above with reference to the drawings, but these are merely examples of the present disclosure, and various configurations other than those described above can be adopted.

[0120] Some or all of the above embodiments may also be described as follows, but are not limited to the following: [Notes] 1. A reflector comprising a plurality of reflector elements, the reflector elements comprising a deflection optical member provided on the incident optical axis of the measurement light and reflecting the measurement light, and a retroreflector provided on the reflected optical axis of the deflection optical member and retroreflecting the measurement light, configured to form a virtual image of the optical center of the reflector element on the extension of the incident optical axis, and the plurality of reflector elements are configured to be combined such that the positions of the virtual images coincide or substantially coincide. 2. A reflector according to item 1 above, wherein the deflection optical member is a reflective prism having an internal reflective surface, the incident optical axis is deflected by the internal reflective surface, the retroreflector is provided on the exit surface of the reflective prism, and the virtual image is configured to be located outside the reflective prism. 3. 1. A reflector as described in item 1 above, wherein the deflection optical member is a reflective prism having an internal reflective surface, the incident optical axis is deflected by the internal reflective surface, the retroreflector is provided on the exit surface of the reflective prism, and the virtual image is formed on or towards the center of the inner end of the reflective prism. 4. A reflector as described in item 1 above, wherein the deflection optical member is a reflective prism having an external reflective surface, the incident optical axis is deflected by the external reflective surface, and the virtual image is located outside the reflective prism. 5. A reflector as described in item 1 above, wherein the deflection optical member is a mirror, the retroreflector is provided on the reflected optical axis reflected externally by the mirror, and the position of the retroreflector is set such that the virtual image is located on or towards the center of the inner end of the mirror. 6. 7. A reflector as described in item 3 above, wherein the angle between the incident optical axis and the reflected optical axis is an acute angle. 8. A reflector as described in item 2 above, wherein two sets of the reflector elements are arranged symmetrically.9. A reflector comprising n sets of the reflector elements in any of the above items 1 to 6, wherein the reflector elements are arranged at W° / n intervals around the virtual image. 10. A reflector comprising n sets of the reflector elements in any of the above items 1 to 6, wherein a reflector unit is formed by arranging n sets of the reflector elements at W° / n intervals around the virtual image, and further configured by combining two sets of reflector units symmetrically vertically. 11. A target device configured to allow the reflector of item 9 to stand on its own. 12. A target device provided with a pole on the reflector of item 9 or 10 such that its axis coincides with or substantially coincides with the position of the virtual image.

[0121] 1 Reflector element 2 Reflecting triangular prism 3 Corner cube prism 4 Incident optical axis 4' Reflected optical axis 6 Reflector 7 Axis 8 Pole 10 Reflector 11 Reflecting prism 16 Reflector 16a Reflector element 21 Reflector 21a Reflector element 22a, 22b Reflector unit 26 Reflector 26a Reflector element 31 Reflector 31a Reflector element 33 Corner cube prism 35 Reflector 35a Reflector element 38 Corner cube prism 39 Reflector 39a Reflector element 43 Reflector 43a Reflector element

Claims

1. A reflector comprising a plurality of reflector elements, each reflector element having a deflection optical member provided on the incident optical axis of the measurement light and reflecting the measurement light, and a retroreflector provided on the reflected optical axis of the deflection optical member and retroreflecting the measurement light, configured to form a virtual image of the optical center of the reflector element on the extension of the incident optical axis, and the plurality of reflector elements are combined such that the positions of the virtual images coincide or substantially coincide.

2. The reflector according to claim 1, wherein the deflecting optical member is a reflective prism having an internal reflective surface, the incident optical axis is deflected by the internal reflective surface, the retroreflector is provided on the exit surface of the reflective prism, and the virtual image is located outside the reflective prism.

3. The reflector according to claim 1, wherein the deflecting optical member is a reflective prism having an internal reflective surface, the incident optical axis is deflected by the internal reflective surface, the retroreflector is provided on the exit surface of the reflective prism, and the virtual image is formed on or towards the center of the inner end of the reflective prism.

4. The reflector according to claim 1, wherein the deflecting optical member is a reflective prism having an outer reflective surface, the incident optical axis is deflected by the outer reflective surface, and the virtual image is located outside the reflective prism.

5. The reflector according to claim 1, wherein the deflection optical member is a mirror, the retroreflector is provided on the reflected optical axis reflected outward by the mirror, and the position of the retroreflector is set such that the virtual image is located on or towards the center of the inner end of the mirror.

6. The reflector according to claim 3, wherein the angle between the incident optical axis and the reflected optical axis is an acute angle.

7. The reflector according to claim 2, configured by arranging two sets of the reflector elements symmetrically.

8. The reflector according to claim 4, wherein the deflection optical member is an isosceles triangular reflective prism having two outer reflective surfaces, the retroreflector is provided opposite each outer reflective surface, and two symmetrical sets of the reflector elements are formed between the retroreflector and the outer reflective surfaces.

9. A reflector according to any one of claims 1 to 6, comprising n sets of the reflector elements, wherein the reflector elements are arranged at W° / n intervals around the virtual image.

10. A reflector according to any one of claims 1 to 6, wherein a reflector unit is formed by combining n sets of the reflector elements at W° / n intervals around the virtual image, and further, two sets of reflector units are combined vertically symmetrically.

11. A target device comprising a reflector according to claim 9 configured to be self-supporting.

12. A target device comprising a reflector according to claim 9 or claim 10, with a pole provided such that its axis coincides with or substantially coincides with the position of the virtual image.

Images