Reflector and target device

Abstract

This reflector comprises: a deflection optical member (5) that is provided on an incident optical axis (3) of measurement light and reflects the measurement light; and a retroreflector (6) that retroreflects the measurement light on a reflection optical axis (3') of the deflection optical member. The reflector is configured to form a virtual image of the optical center of the retroreflector on an extension of the incident optical axis.

Description

Reflector and target device

[0001] The present disclosure relates to a reflector used as a target when making measurements and a target device equipped with the reflector.

[0002] When light wave measurement is performed using a measurement device, a reflector is provided as a target at the measurement point.

[0003] The reflector includes a retroreflector that retroreflects the measurement light, and the measurement device receives the reflected measurement light and measures distance 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 measures angle or distance and angle, and if the measurement device has a tracking function, receives the reflected measurement light and tracks the reflector.

[0004] The retroreflector includes a prism with retroreflectivity such as a corner cube prism, or one composed of three mirrors. Note that the measurement light includes distance measurement light when measuring distance, angle measurement light when measuring angle, and tracking light when tracking the measurement target.

[0005] For example, in the case of a corner cube prism as a retroreflector, the optical center, which is the measurement reference point, is located inside the corner cube prism. In addition, to accurately measure the measurement point using a reflector, it is necessary to install the reflector so that the position of the optical center of the corner cube prism coincides with the measurement point.

[0006] Typically, the reflector is held in a holding device, which includes a reflector housing, a pole to which the housing is attached, and a ferrule to be placed at the measurement point.

[0007] The optical center of the corner cube prism is located inside the corner cube prism. Therefore, when the ferrule is attached to the bottom end of the pole, the optical center is offset from the axis of the pole (see Patent Document 2). In this case, if the reflector is not directly facing the measuring device, an angle error occurs due to the offset.

[0008] Furthermore, when the ferrule is provided on a vertical line passing through the optical center, the ferrule and the pole must be separate bodies (see Patent Documents 3 and 4), which makes the support structure for the reflector complex.

[0009] Japanese Patent Application Laid-Open No. 2007-187857 Japanese Utility Model Application Laid-Open No. 59-34313 Japanese Patent Application Laid-Open No. 2018-21867 Japanese Utility Model Application Laid-Open No. 6-4614 Japanese Patent No. 3551266

[0010] The present disclosure provides a reflector and a target device that, when the reflector is installed at a measurement point, no offset occurs between the measurement reference point and the measurement point of the reflector.

[0011] The present disclosure relates to a reflector that is arranged on the incident optical axis of measurement light and has a deflection optical element that reflects the measurement light and a retroreflector that retroreflects the measurement light on the reflected optical axis of the deflection optical element, and is configured to form a virtual image of the optical center of the retroreflector on an extension of the incident optical axis.

[0012] According to the present disclosure, a reflector can be installed so that the position of the virtual image is located at the measurement point, thereby preventing the occurrence of offset.

[0013] FIG. 1 is an elevation view of a target device according to this embodiment. FIG. 2 is a plan view of a main portion of the target device according to this embodiment. FIG. 3 is a front view of a main portion of the target device according to this embodiment. FIG. 4 is an explanatory diagram of measurement of a measurement point using the target device according to this embodiment. FIG. 5 is a plan view of a first modified example of the target device. FIG. 6 is an elevation view of a second modified example. FIG. 7 is an elevation view of a main portion of a reflector according to the second embodiment. FIG. 8 is a schematic elevation view of a target device according to the third embodiment. FIG. 9 is a schematic elevation view of a target device according to a first modified example of the third embodiment. FIG. 10 is a schematic elevation view of a target device according to a second modified example of the third embodiment. FIG. 11 is a schematic plan view of a target device according to a third modified example of the third embodiment. FIG. 12 is a schematic elevation view of a target device according to a fourth modified example of the third embodiment. FIG. 13 is a schematic elevation view of a target device according to a fifth modified example of the third embodiment. FIG. 14 is a schematic elevation view of a target device according to a sixth modified example of the third embodiment. Figures 15(A), 15(B), and 15(C) show a seventh modified example of the third embodiment, with Figures 15(A) and 15(C) being side views and Figure 15(B) being a plan view. Figures 16(A), 16(B), and 16(C) are explanatory diagrams showing an eighth modified example of the third embodiment. Figures 17(A) and 17(B) show a ninth modified example of the third embodiment, with Figure 17(A) being a plan view of the reflector module and Figure 17(B) being a perspective view of the pole. Figure 18 is a perspective view showing a modified example of the pole. Figure 19 is a schematic elevation view of a target device according to a tenth modified example of the third embodiment. Figure 20 is a schematic elevation view of a target device according to an eleventh modified example of the third embodiment. Figure 21 is a schematic elevation view of a target device according to a twelfth modified example of the third embodiment. Figure 22 is a schematic elevation view of a target device according to a thirteenth modified example of the third embodiment. Fig. 23 is a schematic elevation view of an optical member according to a fourteenth modified example of the third embodiment. Fig. 24 is a schematic elevation view of an optical member according to a fifteenth modified example of the third embodiment. Fig. 25(A) is a schematic side view of an optical member according to a sixteenth modified example of the third embodiment, and Fig. 25(B) is a view taken along arrow A in Fig. 25(A). Fig. 26 is a schematic plan view of an optical member according to a seventeenth modified example of the third embodiment. Fig. 27 is a schematic plan view of an optical member according to an eighteenth modified example of the third embodiment.FIG. 28 is an elevation view of a target device according to a fourth embodiment. FIG. 29 is a plan view of a main portion of a target device according to the fourth embodiment. FIG. 30 is a front view of a main portion of a target device according to the fourth embodiment. FIG. 31 is an elevation view of a main portion of a reflector according to the fourth embodiment. FIG. 32 is an elevation view of a main portion of a reflector according to the fifth embodiment. FIG. 33 is an elevation view of a main portion of a reflector according to the sixth embodiment. FIGS. 34(A) and 34(B) are explanatory diagrams of the optical path of stray light generated in a reflecting triangular prism. FIGS. 35(A) and 35(B) are explanatory diagrams of grooves provided for suppressing stray light. FIG. 36 is an explanatory diagram of measurement of measurement points using a target device according to this embodiment. FIG. 37 is a schematic plan view showing a first modified example of a target device according to this embodiment. FIG. 38 is a schematic elevation view of a second modified example of a target device according to this embodiment. FIG. 39 is a schematic elevation view of a target device according to the seventh embodiment. FIG. 40 is a schematic elevation view of a target device according to the eighth embodiment. Figure 41 is a schematic plan view of a target device according to a ninth embodiment, and Figure 42 is a schematic elevation view of a target device according to a tenth embodiment.

[0014] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0015] 1 to 3 show a first embodiment of the present disclosure, in which 1 indicates a target device, 2 indicates a reflector, and 3 indicates an incident optical axis of the reflector 2. Note that Fig. 1 shows an elevation view of the target device 1, and Figs. 2 and 3 omit a housing 4, which will be described later.

[0016] The reflector 2 will now be described.

[0017] The reflector 2 includes a housing 4, which accommodates and holds an optical member 7. The optical member 7 includes a mirror 5 and a corner cube prism 6, which functions as a retroreflector that retroreflects measurement light from a measurement device 15 (see FIG. 4). The front surface of the housing 4 (the surface onto which the measurement light is incident) is open. As described above, the measurement light includes distance measurement light for measuring distance, angle measurement light for measuring angle, and tracking light for tracking the reflector 2.

[0018] The mirror 5 as a deflection optical member is provided on the incident optical axis 3 and deflects the incident optical axis 3. The corner cube prism 6 is provided on the deflected incident optical axis 3 (reflected optical axis 3').

[0019] The mirror 5 is a surface reflector, and the incident optical axis 3 is incident on the mirror 5 at a required angle. In the figure, the measurement light is incident at 45° and is reflected upward at 90°. Although the incident optical axis 3 is deflected upward by 90°, the deflection angle does not have to be 90° and can be changed as appropriate, for example, by selecting it according to the shape of the housing 4.

[0020] The corner cube prism 6 is placed so that the reflected optical axis 3 ′ passes through the optical center O of the corner cube prism 6 .

[0021] A retroreflective prism or mirror can be used as the retroreflector. For example, in addition to the corner cube prism 6 with three orthogonal reflecting surfaces (the angles between the three reflecting surfaces are 90°, 90°, and 90°), there are also prisms with angles between the three reflecting surfaces of 90°, 90°, 90° / n (natural number) and 90°, 60°, and 45°, and these prisms can be used as the retroreflector. Alternatively, three mirrors with angles between the three reflecting surfaces similar to those of the above prism or the mirror shown in Patent Document 5 can be used as the retroreflector.

[0022] The incident optical axis 3 is reflected and deflected by the mirror 5, so that an apparent optical center (a virtual image of the optical center: hereinafter referred to as virtual image O') is formed on an extension of the incident optical axis 3. The distance from the reflection position (deflection position) R of the incident optical axis 3 to the optical center O is equal to the distance from the reflection position R to the position where the virtual image O' is formed.

[0023] When the reflector 2 is measured as a measurement object, the virtual image O' can be used as a measurement reference point of the reflector 2.

[0024] The position where the virtual image O' is formed is a space where the mirror 5 and the corner cube prism 6 do not exist. That is, the measurement reference point is formed outside the optical member 7. Therefore, a member or means (hereinafter referred to as a transfer means) for transferring the virtual image O' to the measurement point can be provided at the position of the virtual image O', and the optical center (measurement reference point) of the reflector 2 can be set at the measurement point directly or without offset via the transfer means.

[0025] Next, a description will be given of the target device 1 equipped with the reflector 2. The following description will be given for the case where a corner cube prism is used as the retroreflector.

[0026] In the target device 1, the reflector 2 is provided on a pole 8 and is held by the pole 8. The pole 8 serves as a holding member for the reflector 2.

[0027] The pole 8 passes through the housing 4 from top to bottom, and the housing 4 is slidable relative to the pole 8. In the drawing, the pole 8 is provided so as to pass through the inside of the housing 4, but it may also be provided outside the housing 4.

[0028] A ferrule 9 is provided at the lower end of the pole 8, and the tip of the ferrule 9 is located on the axis 10 of the pole 8. The ferrule 9 is tapered, and the tip is pointed, concave, or spherical to make it easy to indicate the measurement point. Furthermore, the positional relationship between the pole 8 and the housing 4 is set so that the virtual image O' is located on the axis 10 of the pole 8.

[0029] Furthermore, the housing 4 is provided with a slide fixing screw 11 that can come into contact with the pole 8, and when the slide fixing screw 11 is loosened, the reflector 2 can slide along the pole 8, and by further tightening the slide fixing screw 11, the reflector 2 can be fixed at any position on the pole 8. Incidentally, the pole 8 may be provided with a scale to check the distance from the tip of the ferrule 9.

[0030] A bubble tube 12 is provided on the top surface of the housing 4 to check the verticality of the pole 8 .

[0031] Fig. 4 shows a case where a measurement point P is measured using the target device 1. In Fig. 4, 15 denotes a measurement device.

[0032] The measuring device 15 is placed at a known point, and the target device 1 is placed at the measuring point P.

[0033] When the target device 1 is placed at a measurement point P, the tip of the ferrule 9 is brought into contact with the measurement point P, and the direction of the incident optical axis 3 is directed toward the measurement device 15. The reflector 2 is set at a predetermined height, and the vertical state of the pole 8 is confirmed by the bubble tube 12, and then measurement is performed. Therefore, the pole 8 functions as an indicator that indicates the measurement point.

[0034] At this time, even if the reflector 2 is not exactly facing the measuring device 15 and the measurement light is obliquely incident on the reflector 2, the virtual image O' (measurement reference point) is located on the axis 10 of the pole 8, i.e., the measurement reference point is vertically above the measurement point P, so no measurement error occurs.

[0035] Therefore, human error by the operator is reduced, and the operator is not required to have high skill, and measurement accuracy is improved.

[0036] Furthermore, since the pole 8 has a structure in which the reflector 2 is simply inserted, the structure of the target device 1 is simple.

[0037] Figure 5 shows a first modified example of the target device 1, and is a plan view of the reflector 2. In Figure 5, the same components as those shown in Figure 1 are designated by the same reference numerals, and their description will be omitted.

[0038] The reflector 2 has the same configuration as in the above embodiment. In the first modification, the reflector 2 is rotated by 90° around the incident optical axis 3, and the incident optical axis 3 is deflected horizontally by a mirror 5.

[0039] The pole 8 is inserted vertically through the reflector 2, and the axis 10 passes through the virtual image O'. Therefore, in FIG. 5, the pole 8 is perpendicular to the paper surface.

[0040] 6 shows a second modified example, in which a window glass 16 is provided on the front surface (the surface on which the measurement light enters) of the housing 4. By providing the window glass 16, the mirror 5 and the corner cube prism 6 can be protected from dirt and deterioration.

[0041] The housing 4 has a sealed structure, and cleaning can be performed simply by removing dirt from the window glass 16. The window glass 16 may be made detachable, allowing cleaning of the mirror 5 and the corner cube prism 6.

[0042] FIG. 7 shows the main part of a reflector 17 according to the second embodiment.

[0043] In the reflector 17, a reflecting triangular prism 18 is used as a deflection optical member instead of the mirror 5. Incidentally, structural members such as the housing 4 are not shown in FIG.

[0044] The reflecting triangular prism 18 has an incident surface 18a perpendicular to the incident optical axis 3, and a reflecting surface 18b reflects and deflects the incident optical axis 3 at a predetermined angle. In the drawing, the incident angle of the incident optical axis 3 with respect to the incident surface 18a is 45° and the deflection angle is 90°. The exit surface 18c is perpendicular to the reflected optical axis 3'.

[0045] A corner cube prism 6 is provided on the exit surface 18c, and the optical center O of the corner cube prism 6 is set to be located on the reflected optical axis 3'. Furthermore, by providing the corner cube prism 6 on the reflecting triangular prism 18, the optical center O" of the composite of the corner cube prism 6 and the reflecting triangular prism 18 moves toward the reflection position R. Furthermore, a virtual image O' (measurement reference point) is formed on an extension of the incident optical axis 3 and at a position symmetrical with respect to the reflecting surface 18b.

[0046] The reflector 17 is attached to the pole 8 so that the axis 10 of the pole 8 is perpendicular to the extension of the incident optical axis 3 and passes through the virtual image O' (measurement reference point).

[0047] The corner cube prism 6 may be attached to the exit surface 18c by bonding, by being placed in close contact with the prism, or by being placed with a gap between them. When a gap is placed between the corner cube prism 6 and the reflecting triangular prism 18, the corner cube prism 6 and the reflecting triangular prism 18 are separate members, and therefore the virtual image O' is formed on the extension of the incident optical axis 3 and at a position symmetrical with respect to the optical center O and the reflecting surface 18b.

[0048] Furthermore, a reflective film may or may not be formed on the reflective surface 18b.

[0049] In the second embodiment, the use of the reflecting triangular prism 18 allows further miniaturization.

[0050] In the above embodiment, a triangular pyramidal shape is used as the corner cube prism 6, but it is not limited to a triangular pyramidal shape, and a corner cube with cylindrical side surfaces may also be used.

[0051] The corner cube is not limited to a triangular pyramid shape, but may be any optical member having a retroreflective effect.

[0052] Furthermore, the retroreflector may not be a prism, but may be composed of three mirrors that reflect light from their surfaces.

[0053] Next, a target device 21 according to a third embodiment will be described with reference to Fig. 8. In Fig. 8, the same components as those shown in Fig. 1 are designated by the same reference numerals, and their description will be omitted.

[0054] The target device 21 can be installed without using a pole 8. The target device 21 has a pointer section (described later) attached to the reflector 2, and is configured to function as a target device.

[0055] In the target device 21, the housing 4 functions as a holding member for the optical members, and also functions as an indicator for indicating the position of the virtual image O', as will be described later.

[0056] The rear wall 4a on the side opposite to the incident side (rear side) of the housing 4 is made to protrude rearward to form a protrusion, and a tip 24 is formed on the protrusion so that the tip 24 is located on an extension of the incident optical axis 3 and so that the position of the tip 24 coincides with the virtual image O'. As a method of forming the tip 24, as shown in Figure 8, the rear wall 4a may be made conical and its apex may be made the tip 24, or a part of the rear wall 4a may be made to protrude and the tip 24 may be formed on the protrusion.

[0057] In the third embodiment, the protrusion and the tip 24 form a pointer.

[0058] FIG. 9 shows a target device 21 according to a first modification of the third embodiment.

[0059] In the first modification, the shape of the rear wall 4a forming the tip 24 is made even sharper. By making the side wall shape sharper, it becomes easier to align the tip 24 with the measurement point, and there is no wasted space inside the housing 4, which allows the target device 21 to be made smaller.

[0060] 10 shows a target device 21 according to a second modification of the third embodiment. In the second modification, the target device 21 is also configured by adding a pointer to the reflector 2.

[0061] In the second modification, a protrusion formed on the rear wall 4a of the housing 4 is shaped to envelop the mirror 5 and the corner cube prism 6, and a probe 25 is formed on the protrusion so as to protrude along the extension of the incident optical axis 3, with the tip 24 of the probe 25 aligned with the position of the virtual image O'. Although the probe 25 is shown hollow in the drawing, it may also be a solid member. In the second modification, the protrusion and the probe 25 form the pointing portion.

[0062] In the second modified example, it becomes easier to align the tip 24 of the probe 25 with the measurement point, and the target device 21 can be made even more compact.

[0063] Figure 11 shows a target device 21 according to a third modified example. In this third modified example, a pointer is separately attached to the housing 4. Note that Figure 11 is a plan view, and in Figure 11, parts equivalent to those shown in Figure 1 are given the same reference numerals and their explanation will be omitted. In the third modified example, the reflected light axis 3' is deflected horizontally, and the pole 8 is perpendicular to the plane of the drawing.

[0064] In the third modification, an adapter for setting the virtual image O' (measurement reference point) at the measurement point is detachably provided on the rear wall 4a of the housing 4.

[0065] 11 is a pole holder 26, which is detachable from the rear surface of the housing 4 and has a hole 27 through which a pole can be inserted. When the pole holder 26 is attached to the housing 4, the center of the hole 27 coincides with the position of the virtual image O'.

[0066] By inserting a pole having a ferrule at the lower end into the hole 27, a target device having the same function as the target device 1 shown in Fig. 1 is formed. In the third modification, the pole holder 26 and the pole 8 form a support portion.

[0067] FIG. 12 shows a target device 21 according to a fourth modified example.

[0068] The indicator shown in FIG. 12 is a probe 28 that is detachably attached to the rear wall 4a of the housing 4, and the probe 28 is provided on an extension of the incident optical axis 3. The probe 28 has a tip 24 that is aligned with the position of the virtual image O'.

[0069] When the probe 28 is attached to the housing 4, it has the same function as the target device 21 of the second modified example shown in Fig. 10. The probe 28 functions as an indicator for indicating the virtual image O'.

[0070] The pole holder 26 and the probe 28 may be fixed to the housing 4, but the pole holder 26 and the probe 28 may have the same mounting structure and be interchangeable depending on the measurement conditions.

[0071] FIG. 13 shows a target device 21 according to a fifth modified example.

[0072] In the fifth modified example shown in Fig. 13, the probe 25 of the second modified example shown in Fig. 10 is separated from the housing 4, and the probe 25 is made into a separate part, and furthermore, a fitting portion 25' is provided on the probe 25 so that it can be attached to and detached from the housing 4. It should be noted that the shape of the fitting portion 25' is not limited to that shown in the figure.

[0073] When the probe 25 is attached to the housing 4, it has the same function as the second modified example, and the tip 24 of the probe 25 is positioned where a virtual image O' is formed.

[0074] In the sixth modified example shown in Fig. 14, a pole holder 29 is attached to the location where the probe 25 was removed. The pole 8 can be inserted into the pole holder 29, and the pole 8 can be fixed at any position (see Fig. 1). In addition, a virtual image O' is positioned on the axis 10 of the pole 8.

[0075] The pole holder 29 is also configured to be detachable from the housing 4, and is replaceable with the probe 25. Therefore, the probe 25 and the pole holder 29 may be replaced depending on the measurement situation.

[0076] Figures 15(A), 15(B), and 15(C) show the seventh modified example, with Figure 15(A) being a side view and Figure 15(B) being a plan view. In Figures 15(A) and 15(B), parts equivalent to those shown in Figure 1 are given the same reference numerals.

[0077] In FIGS. 15A, 15B and 15C, reference numeral 30 denotes a reflector module in which optical members including a deflection optical member and a corner cube prism are integrated with the housing.

[0078] A pole holder 31 is provided on the pole 8 so as to be slidable, and the pole holder 31 can be fixed at any position on the pole 8 by a slide fixing screw 11 .

[0079] A connecting member 32 is provided on the rear wall 4a of the reflector module 30, and the connecting member 32 is rotatably connected to the pole holder 31 via a horizontal rotation shaft 33. An axis 34 of the horizontal rotation shaft 33 is perpendicular to the axis 10 of the pole 8 and passes through the position of the virtual image O'. Therefore, the position where the virtual image O' is formed is the intersection of the axis 10 and the axis 34.

[0080] The reflector module 30 is rotatable in the vertical direction relative to the pole 8 via the horizontal rotation shaft 33. The rotation center of the reflector module 30 is the position of the virtual image O', so the position of the virtual image O' (measurement reference point) does not change due to rotational movement of the reflector module 30. In other words, even if the reflector module 30 slides or rotates, the measurement reference point is always located on the axis 10.

[0081] The connecting member 32 is provided with a rotation fixing screw 35, which allows the reflector module 30 to be fixed at any angle.

[0082] FIG. 15C shows a state in which the reflector module 30 has been rotated upward by a required angle.

[0083] 16(A), 16(B), and 16(C) show an eighth modified example.

[0084] A connector 37 is provided on the rear wall 4 a of the reflector module 30 .

[0085] The pole 8 and the pole holder 31 are assembled into a unit called a support part 39a. The pole holder 31 is provided with a connectable part 38 that can be disconnected from the connectable part 37, and the reflector module 30 and the support part 39a are integrated by connecting the connectable part 37 and the connectable part 38. In the integrated state, the position of the virtual image O' of the reflector module 30 is located on the axis of the pole 8, similar to the seventh modified example shown in Figure 15(A) (see Figure 16(B)).

[0086] The connection between the connector 37 and the connector 38 can be released when the connector 37 and the connector 38 are rotated by 90° or 180° relative to each other. With this configuration, the reflector module 30 can be attached to the support portion 39a when rotated by 90° or 180°.

[0087] Next, the probe 25 capable of indicating a measurement point and the connecting member 38 capable of being disconnected from the connecting member 37 are unitized as an indicating part 39b. The connecting member 38 of the indicating part 39b and the connecting member 38 of the indicating part 39a have a common structure.

[0088] When the indicator 39b is attached to the reflector module 30, the tip of the probe 25 is positioned at the virtual image O' of the reflector module 30, and the reflector module 30 can be directly placed at the measurement point (see Figure 16 (C)).

[0089] Thus, the reflector module 30 can be attached to either the support portion 39a or the support portion 39b.

[0090] The connector 37 and the connector 38 may be a coupling of a fitting type or a coupling of a screw connection type, as long as they are easily attachable and detachable.

[0091] Figures 17(A) and 17(B) show a ninth modified example, in which a pole 8 is used as the indicator. In Figure 17(A), the same reference numerals are used to designate the same components as those shown in Figure 10, and their description will be omitted.

[0092] An engaging protrusion 44 is formed on the rear wall 4a of the reflector module 30, extending on the extension of the incident optical axis 3. In addition, a groove 43 is provided as a recess in the pole 8, and the groove 43 is formed along the axis of the pole 8.

[0093] The engaging protrusion 44 can be fitted into any position of the groove 43 and can be fixed to the groove 43 at any position, so that the reflector module 30 is supported by the pole 8 at any position. Furthermore, with the engaging protrusion 44 fitted into the groove 43, the formation position of the virtual image O' is configured to be on the axis of the pole 8.

[0094] As a fixing means, the engaging protrusion 44 is made of a magnet, and by attraction, the fitted state with the groove 43 is maintained. Alternatively, as a fixing means, an elastic material such as a leaf spring is provided on the engaging protrusion 44 to press against the groove 43, and the engaging protrusion 44 is fixed to the groove 43 by frictional force.

[0095] Incidentally, a scale indicating the distance from the tip of the ferrule 9 may be engraved on the pole 8 so that the fixed position of the reflector module 30 (the position of the virtual image O') can be determined. Also, the engaging protrusion 44 may be used as a probe, and the tip of the engaging protrusion 44 may be set at the position where the virtual image O' is formed, so that the reflector module 30 alone can be installed at the measurement point.

[0096] 18 shows a modified example of the pole 8, in which a plurality of fitting holes 45 are drilled as recesses instead of the grooves 43. The fitting holes 45 are provided in a required number at known intervals at known positions from the tip of the ferrule 9, and are capable of fitting with the engaging protrusions 44. The engaging protrusions 44 are made of magnets, so that the fitted state between the engaging protrusions 44 and the fitting holes 45 is maintained. Alternatively, the shape of the fitting holes 45 is such that the fitted state is maintained when the engaging protrusions 44 are fitted. Also, a scale may be engraved on the pole 8.

[0097] It goes without saying that the shape of the recess is not limited to the above-mentioned shape.

[0098] Fig. 19 shows a tenth modified example. In Fig. 19, the same reference numerals are used to designate the same parts as those shown in Fig. 9, and the description thereof will be omitted.

[0099] In the tenth modification, the incident optical axis 3 is deflected multiple times, so that the virtual image O' is formed at a position farther away from the incident optical axis 3.

[0100] A plurality of mirrors are used as deflection optical members for deflecting the light multiple times. In the tenth modification, two mirrors 5 and 5a are used, and the reflected light axis 3' is deflected by 90 degrees by the mirror 5a. That is, the incident light axis 3 is deflected twice by the mirrors 5 and 5a.

[0101] In this modification, the deflection angle is 90° for each of the mirrors 5 and 5a, but it is not limited to 90°. Also, in this modification, the deflection directions of the mirrors 5 and 5a are in the same plane (parallel to the paper), but they may be deflected in a direction perpendicular to the paper. Also, in this modification, the light is deflected twice, but it goes without saying that it may be deflected three or four times.

[0102] The tenth modification shown in Fig. 19 corresponds to the first modification shown in Fig. 9, in which a mirror 5a is provided opposite the mirror 5, and the reflected optical axis 3' is further deflected by this mirror 5a. A corner cube prism 6 is provided on the reflected optical axis 3" deflected by the mirror 5a. The reflected optical axis 3" is set to pass through the optical center O of the corner cube prism 6.

[0103] A virtual image O' of the optical center O is formed on an extension of the incident optical axis 3, but the distance from the reflection position R on the mirror 5 to the optical center O is equal to the distance from the reflection position R to the virtual image O'.

[0104] By deflecting the incident optical axis 3 twice, the distance from the reflection position R to the optical center O becomes longer, and the distance from the reflection position R to the virtual image O' also becomes longer. Therefore, the rear wall 4a forming the tip 24 becomes sharper, making it easier to align the tip 24 with the measurement point.

[0105] Fig. 20 shows an eleventh modified example. The eleventh modified example shown in Fig. 20 corresponds to the second modified example in Fig. 10, in which the incident optical axis 3 is deflected twice by the mirrors 5, 5a, the distance between the reflection position R and the virtual image O' is increased, and the length of the probe 25 is also increased, improving the workability when aligning the tip 24 with the measurement point.

[0106] Fig. 21 shows a twelfth modified example. In Fig. 21, the same reference numerals are used to designate the same components as those shown in Fig. 19, and the description thereof will be omitted.

[0107] In the twelfth modification shown in FIG. 21, the mirrors 5 and 5a, which are the deflection optical members in the tenth modification shown in FIG.

[0108] The reflecting prism 41, which serves as a deflecting optical member, has two orthogonal reflecting surfaces 31a and 31b, which reflect the incident measurement light twice and deflect twice the incident optical axis 3. Although the apex angle of the reflecting prism 41 is shown as 90° in the drawing, it is not limited to 90° and may be changed as appropriate according to the manufacturing conditions of the target device 21.

[0109] Fig. 22 shows a thirteenth modified example. In Fig. 22, the same reference numerals are used to designate the same parts as those shown in Fig. 20, and the description thereof will be omitted.

[0110] In the thirteenth modification shown in FIG. 22, the mirrors 5 and 5a, which are the deflection optical members in the eleventh modification shown in FIG.

[0111] In the twelfth and thirteenth modified examples shown in FIGS. 21 and 22, the reflecting prism 41 and the corner cube prism 6 are spaced apart from each other, but they may be in close contact with each other or joined together.

[0112] Fig. 23 shows a fourteenth modification example, in which the housing 4 is omitted and only the optical members are shown.

[0113] In the fourteenth modification, the deflection optical member is composed of a mirror 5 and a reflecting triangular prism 18, and the deflection optical member deflects the incident optical axis 3 twice. The first deflection is performed by the mirror 5, and the second deflection is performed by the reflecting triangular prism 18.

[0114] FIG. 24 shows a fifteenth modified example.

[0115] In the fifteenth modification, similarly to the fourteenth modification, the deflection optical member is composed of a mirror 5 and a reflecting triangular prism 18, and the deflection optical member deflects the incident optical axis 3 twice. The first deflection is performed by the reflecting triangular prism 18, and the second deflection is performed by the mirror 5.

[0116] 25(A) and 25(B) show a sixteenth modified example.

[0117] In the sixteenth modification, the deflection optical member is constituted by one deflection prism 42, which has two opposing reflecting surfaces 42a and 42b, and is configured so that the incident optical axis 3 is deflected twice by the reflecting surfaces 42a and 42b. The reflecting surface 42b deflects the optical axis in a direction perpendicular to a plane including the reflected optical axis 3' deflected by the reflecting surface 42a and the incident optical axis 3.

[0118] The fourteenth, fifteenth, and sixteenth modifications described above each allow for miniaturization and widening of the angle of view.

[0119] FIG. 26 shows a seventeenth modified example.

[0120] In the seventeenth modification, a mirror 46 is used as the deflection optical member, and the corner cube prism 6 is provided directly opposite the center of the reflecting surface 46 a of the mirror 46 .

[0121] In the seventeenth variant, the incident optical axis 3 is obliquely incident on the mirror 46 from the side of the corner cube prism 6, and the corner cube prism 6 is positioned on the reflected optical axis 3' deflected by the mirror 46.

[0122] A virtual image O' of the optical center O of the corner cube prism 6 is located on an extension of the incident optical axis 3 and is formed at a position symmetrical with respect to the reflecting surface of the mirror 46.

[0123] The measurement light beams incident on both sides of the corner cube prism 6 within the angle range of α with the virtual image O' as the center enter the corner cube prism 6 and are retroreflected.

[0124] In the seventeenth modification, the measurement light can be retroreflected at a wide angle of view.

[0125] FIG. 27 shows an eighteenth modified example.

[0126] In the eighteenth modification, a plane-parallel plate 47 with a mirror is used as the deflection optical member.

[0127] The rear surface 47a of the mirrored parallel plane plate 47 is a reflecting surface, and a corner cube prism 6 is provided on the surface of the mirrored parallel plane plate 47. This modification has the same optical effect as the seventeenth modification, and since the corner cube prism 6 is provided on the mirrored parallel plane plate 47, it has a compact configuration.

[0128] According to the present disclosure described above, the measurement reference point of the reflector can be set to a virtual image position with respect to the optical element, and further, the measurement reference position exists outside the optical element, and the measurement reference position can be set to the measurement point without offset.

[0129] Next, there are cases where the measurement light is incident on the reflector along a path other than the normal optical path and is retroreflected, and when the measurement device receives and measures the retroreflected light along a path other than the normal optical path, an error occurs (hereinafter, retroreflected light along a path other than the normal optical path is referred to as stray light). Therefore, it is desirable to take measures to prevent or suppress the generation of stray light.

[0130] The following embodiments disclose a reflector and target device that, when a reflector is installed at a measurement point, does not cause an offset between the measurement reference point and the measurement point of the reflector, and further suppresses the generation of stray light.

[0131] Hereinafter, an embodiment in which measures against stray light are taken to suppress the generation of stray light will be described.

[0132] Figures 28 to 30 show a target device equipped with a reflector 2 according to a fourth embodiment in which measures against stray light have been taken. In Figures 28 to 30, parts equivalent to those shown in Figures 1 to 3 are given the same reference numerals and their explanation will be omitted.

[0133] First, a configuration for suppressing the generation of stray light in the reflector 2 of the fourth embodiment will be described with reference to FIG.

[0134] If the reflector 2 is not directly facing the measuring device and the measurement light is incident on the reflector 2 via a path other than the normal optical path, and if the measurement light is incident directly on the corner cube prism 6 without being reflected by the mirror 5, the measurement light will be retroreflected by the corner cube prism 6, generating stray light.

[0135] In the fourth embodiment, a first light-shielding portion is provided at the front end (the end on the measuring device side) of the reflecting surface of the mirror 5. The first light-shielding portion is a first light-shielding plate 50 made of an opaque plate material, and the width dimension of the first light-shielding plate 50 (the dimension in the direction perpendicular to the paper surface of FIG. 31) is the same as or approximately the same as the width of the mirror 5, and the height is dimensioned so as not to block or approximately not to block the measurement light incident on the normal optical path.

[0136] The first light blocking plate 50 prevents the light ray N1 from entering the corner cube prism 6 from outside the normal optical path, thereby suppressing the generation of stray light.

[0137] A second light-shielding portion is provided at the front end of the corner cube prism 6. The second light-shielding portion is a second light-shielding plate 51 made of an opaque plate material, and the width of the second light-shielding plate 51 (the dimension perpendicular to the paper surface of FIG. 31) is the same as or approximately the same as the width of the corner cube prism 6 (see FIGS. 29 and 30), and the height is sized so as not to block or approximately not block the measurement light incident on the normal optical path.

[0138] The second light blocking plate 51 prevents the light ray N2 from entering the corner cube prism 6 from outside the normal optical path, thereby suppressing the generation of stray light.

[0139] In addition, when the first light-shielding plate 50 and the second light-shielding plate 51 can each independently provide a sufficient light-shielding effect for practical use, either one of them may be omitted.

[0140] FIG. 32 shows a fifth embodiment. In this fifth embodiment, a first hood 52 is provided as a first light-shielding portion at the front end (the end on the measurement device side) of the mirror 5. The first hood 52 is made of an opaque plate material, and its width (the dimension perpendicular to the paper surface of FIG. 32 ) is the same as or approximately the same as the mirror 5. The first hood 52 extends forward and is tilted in a direction away from the incident optical axis 3. The tilt angle of the first hood 52 is set so as not to block the measurement light incident on the mirror 5 along the normal optical path. The length of the first hood 52 is set to prevent light ray N3 from below the mirror 5 from entering the corner cube prism 6.

[0141] A second hood 53 is provided in front of the corner cube prism 6 as a second light-blocking section. The second hood 53 is made of an opaque plate material, and its width is approximately the same as that of the mirror 5, or at least the same as or approximately the same as that of the corner cube prism 6 (see Figures 29 and 30). The second hood 53 extends forward and is tilted in a direction away from the incident optical axis 3. The tilt angle of the second hood 53 is set so as not to block the measurement light incident on the mirror 5 via the normal optical path. The length of the second hood 53 is set to prevent light ray N4 from below the mirror 5 from entering the corner cube prism 6.

[0142] The first hood 52 and the second hood 53 may be parallel to the incident optical axis 3 or may be inclined so as to approach the incident optical axis 3. It is sufficient that the effect of suppressing stray light is exhibited. Furthermore, the first hood 52 (lower part in the figure) and the second hood 53 (upper part in the figure) may be provided as independent members with different shapes, or may be members with different opening shapes in the direction perpendicular to the plane of the paper and in the up-down direction of the paper.

[0143] The first hood 52 and the second hood 53 are installed so that the opening becomes wider toward the front. If the first hood 52 or the second hood 53 can each provide a practically sufficient light blocking effect by itself, one of them may be omitted. The shape and size of the light blocking plate are determined taking into consideration the shape and size of the corner cube prism, the size of the deflection mirror, product specifications, etc.

[0144] Fig. 33 shows a sixth embodiment, in which a reflecting triangular prism 18 is used as the deflecting optical element. Note that structural elements such as the housing 4 are not shown in Fig. 33.

[0145] The reflecting triangular prism 18 has an incident surface 18a perpendicular to the incident optical axis 3, and a reflecting surface 18b reflects and deflects the incident optical axis 3 at a predetermined angle. In the figure, the incident angle of the incident optical axis 3 with respect to the reflecting surface 18b is 45°, and the deflection angle is 90°. Note that the deflection angle is not limited to 90°. Furthermore, the exit surface 18c is perpendicular to the reflected optical axis 3'. A reflective film may or may not be formed on the reflecting surface 18b.

[0146] A corner cube prism 6 is provided on the exit surface 18c, and the optical center O of the corner cube prism 6 is set to be located on the reflected optical axis 3'. By providing the corner cube prism 6 on the reflecting triangular prism 18, the optical center O" of the composite including the reflecting triangular prism 18 and the corner cube prism 6 moves toward the reflection position R. In addition, a virtual image O' (measurement reference point) is formed on an extension of the incident optical axis 3 and at a position symmetrical with respect to the reflecting surface 18b.

[0147] The corner cube prism 6 and the reflecting triangular prism 18 are bonded together with an adhesive, or are provided in close contact with each other, or are provided with a gap between them, or in any other suitable manner. When the corner cube prism 6 is bonded to the reflecting triangular prism 18, total reflection that occurs at the bonding point on the exit surface 18c is suppressed, thereby preventing the generation of stray light. When a gap is provided, the corner cube prism 6 and the reflecting triangular prism 18 are separate members, so that a virtual image O' is formed on an extension of the incident optical axis 3 and at a position symmetrical with respect to the optical center O and the reflecting surface 18b.

[0148] Next, with reference to Figures 34(A) and 34(B), we will explain the stray light generated in the reflecting triangular prism 18. Figures 34(A) and 34(B) show a triangular prism that has not been designed to deal with stray light.

[0149] 34(A) shows the case where a light ray N6 that deviates from the normal optical path is incident on the lower end of the incident surface 18a (the front end of the reflecting surface 18b). The light ray N6 is sequentially internally reflected by the reflecting surface 18b and the incident surface 18a, enters the corner cube prism 6, and is retroreflected by the corner cube prism 6. If this retroreflected light is received by the measuring device, it will result in an erroneous measurement.

[0150] 34(B) shows the case where a light ray N5 that deviates from the normal optical path is incident from the upper end of the incident surface 18a. The light ray N5 is sequentially internally reflected by the exit surface 18c and the reflecting surface 18b, enters the corner cube prism 6, and is retroreflected by the corner cube prism 6. If this retroreflected light is received by the measuring device, an erroneous measurement will occur.

[0151] The countermeasure against stray light in the sixth embodiment will be described with reference to FIG.

[0152] A first light-shielding portion is formed at the lower end of the incident surface 18a (i.e., the portion where the incident surface 18a and the reflecting surface 18b intersect). The first light-shielding portion is a chamfered portion 54. The formation of the chamfered portion 54 prevents the incidence of light ray N6 that deviates from the normal optical path (see FIG. 34A). The size of the chamfered portion 54 is determined so as to prevent the light ray N6 from deviating from the normal optical path from entering the corner cube prism 6 and to prevent the generation of stray light.

[0153] The first light-shielding portion prevents the incidence of light ray N6 outside the normal optical path from the lower end of the incident surface 18a, and various modifications are possible. For example, instead of the chamfered portion 54, other means may be used, such as applying a light-shielding coating to the lower end of the incident surface 18a, scattering light by sandblasting or the like, partially altering the glass, or generating a large number of minute voids inside the reflecting triangular prism 18 with a laser beam to form light-shielding portions equivalent to the chamfered portion 54.

[0154] A second light-blocking portion is provided at the position of the front end of the corner cube prism 6 on the exit surface 18c. This second light-blocking portion suppresses internal reflection of ray N5 at the exit surface 18c, and FIG. 33 shows a groove 55a formed perpendicular to the exit surface 18c. The groove 55a prevents ray N5, which is internally reflected at the exit surface 18c, from traveling toward the reflecting surface 18b (see FIG. 34(B)). The width of the groove 55a (in the direction perpendicular to the paper) need only be greater than the width of the corner cube prism 6. The depth of the groove 55a is set to prevent ray N5 from entering the corner cube prism 6 from outside the normal optical path.

[0155] The second light blocking portion may be configured in various ways as long as it prevents the light ray N5 from being reflected by the light exit surface 18c or from heading toward the reflecting surface 18b.

[0156] For example, as shown in Fig. 35(A), grooves 55b having a semicircular cross section may be formed, or as shown in Fig. 35(B), grooves 55c having a V-shaped cross section may be formed. Alternatively, the portions of the exit surface 18c other than the corner cube prisms 6, at least the portions in front of the corner cube prisms 6, may be subjected to surface treatment such as the formation of an anti-reflection film, painting, or sandblasting. Alternatively, minute voids may be generated by a laser beam to form light-shielding portions equivalent to the grooves 55a.

[0157] In the sixth embodiment, the reflector 2 can be made smaller by using the reflecting triangular prism 18 .

[0158] In addition, in the reflecting triangular prism 18, the entrance surface 18a and the exit surface 18c other than the portions where the corner cube prism 6 is provided, as well as both side surfaces, may be subjected to anti-reflection treatment, such as graining or anti-reflection coating.

[0159] 28 to 30, a target device 1 equipped with the reflector 2 will be described. Note that the reflector 2 according to the fourth embodiment is exemplified as the reflector 2. It goes without saying that the reflector 2 according to the fifth embodiment and the reflector 2 according to the sixth embodiment can also be applied in the same manner.

[0160] In the target device 1, the reflector 2 is provided on a pole 8 and is held by the pole 8. The pole 8 serves as a holding member for the reflector 2.

[0161] The pole 8 passes through the housing 4 from top to bottom, and the housing 4 is slidable relative to the pole 8. In the drawing, the pole 8 is provided so as to pass through the inside of the housing 4, but it may also be provided outside the housing 4.

[0162] A ferrule 9 is provided at the lower end of the pole 8, and the tip of the ferrule 9 is located on the axis 10 of the pole 8. Furthermore, the positional relationship between the pole 8 and the housing 4 is set so that the virtual image O' is located on the axis 10 of the pole 8.

[0163] Furthermore, the housing 4 is provided with a fixing screw 11 that can come into contact with the pole 8, and when the fixing screw 11 is loosened, the reflector 2 can be moved along the pole 8, and by further tightening the fixing screw 11, the reflector 2 can be fixed at any position on the pole 8. The pole 8 may be provided with a scale to check the distance from the tip of the ferrule 9.

[0164] A bubble tube 12 is provided on the top surface of the housing 4 to check the verticality of the pole 8 .

[0165] Fig. 36 shows a case where a measurement point is measured using the target device 1. In Fig. 36, 15 denotes a measurement device.

[0166] The measuring device 15 is placed at a known point, and the target device 1 is placed at the measuring point P.

[0167] When the target device 1 is placed at a measurement point P, the tip of the ferrule 9 is brought into contact with the measurement point P, and the direction of the incident optical axis 3 is directed toward the measurement device 15. The reflector 2 is set at a predetermined height, and the vertical state of the pole 8 is confirmed by the bubble tube 12, and then measurement is performed. Therefore, the pole 8 functions as an indicator that indicates the measurement point.

[0168] At this time, if the measurement light deviates from the normal optical path and enters the reflector 2 at an angle, stray light is suppressed, so there is no retroreflection from the corner cube prism 6 along any path other than the normal optical path, and measurement is not performed along any path other than the normal optical path. When the measurement light enters the reflector 2 along the normal optical path, the measurement light is retroreflected by the corner cube prism 6 and measurement is performed. Furthermore, even if the reflector 2 is not exactly facing directly, the virtual image O' (measurement reference point) is located on the axis 10 of the pole 8, that is, the measurement reference point is at the same height vertically as the measurement point P, so no measurement error occurs.

[0169] Therefore, human error by the operator is reduced, and the operator is not required to have high skill, and measurement accuracy is improved.

[0170] Furthermore, since the pole 8 has a structure in which the reflector 2 is simply inserted, the structure of the target device 1 is simple.

[0171] Figure 37 shows a first modified example of the target device 1, and is a plan view of the reflector 2. The modified example shown in Figure 37 shows a case where a first light-shielding plate 50 is provided at the front end (the end on the measurement device side) of the reflecting surface of the mirror 5, and a second light-shielding plate 51 is provided at the front end of the corner cube prism 6.

[0172] The reflector 2 has the same configuration as in the above embodiment. In the first modification, the reflector 2 shown in the first embodiment is rotated by 90° around the incident optical axis 3, and the incident optical axis 3 is deflected horizontally by a mirror 5.

[0173] The pole 8 is inserted vertically through the reflector 2, and the axis 10 passes through the virtual image O'. Therefore, in Figure 37, the pole 8 is perpendicular to the paper surface.

[0174] 38 shows a second modified example, in which a window glass 16 is provided on the front surface (the surface on which the measurement light enters) of the housing 4. By providing the window glass 16, the mirror 5 and the corner cube prism 6 can be protected from dirt and deterioration.

[0175] The housing 4 has a sealed structure, and cleaning can be performed simply by removing dirt from the window glass 16. The window glass 16 may be made detachable, allowing cleaning of the mirror 5 and the corner cube prism 6.

[0176] Next, a target device 21 according to a seventh embodiment will be described with reference to Fig. 39. In Fig. 39, the same components as those shown in Fig. 28 are given the same reference numerals and their description will be omitted.

[0177] The target device 21 can be installed without using a pole 8. In the target device 21, a pointer portion (to be described later) is added to the reflector 2, and the target device 21 is configured to function as a target device.

[0178] In the target device 21, the housing 4 functions as a holding member for the optical members, and also functions as an indicator for indicating the position of the virtual image O', as will be described later.

[0179] The rear wall 4a on the side opposite to the incident side (rear side) of the housing 4 is made to protrude rearward to form a protrusion, and a tip 24 is formed on the protrusion so that the tip 24 is located on an extension of the incident optical axis 3 and so that the position of the tip 24 coincides with the virtual image O'. As a method of forming the tip 24, as shown in Figure 39, the rear wall 4a may be made to have a conical shape or a pyramidal shape such as a square pyramid, and the apex of the cone may be made to be the tip 24, or a part of the rear wall 4a may be made to protrude, and the tip 24 may be formed on the protrusion.

[0180] In the seventh embodiment, the protrusion and the tip 24 form a pointer.

[0181] 40 shows a target device 21 according to an eighth embodiment. In the eighth embodiment, the target device 21 is also configured by adding a pointer to the reflector 2. In FIG. 40, the same reference numerals are used to designate the same parts as those shown in FIG. 28, and their explanation will be omitted.

[0182] In the eighth embodiment, a protrusion formed on the rear wall 4a of the housing 4 is shaped to envelop the mirror 5 and the corner cube prism 6, and a rod-shaped probe 25 is formed on the protrusion along the extension of the incident optical axis 3, with the tip 24 of the probe 25 aligned with the position of the virtual image O'. Although the probe 25 is hollow in the drawing, it may be a solid member. In the eighth embodiment, the protrusion and the probe 25 form the pointing portion.

[0183] In the eighth embodiment, the probe 25 is rod-shaped, which makes it easier to align the tip 24 of the probe 25 with the measurement point and also allows the target device 21 to be made even more compact.

[0184] Figure 41 shows a target device 21 according to a ninth embodiment. In this ninth embodiment, the pointer is attached separately to the housing 4. Note that Figure 41 is a plan view, and in Figure 41, parts equivalent to those shown in Figure 28 are given the same reference numerals and their explanation will be omitted. In the ninth embodiment, the reflected light axis 3' is deflected horizontally, and the pole 8 is perpendicular to the plane of the drawing.

[0185] In the ninth embodiment, an adapter for setting the virtual image O' (measurement reference point) at the measurement point is detachably provided on the rear wall 4a of the housing 4.

[0186] 41 is a pole holder 26, which is detachable from the rear surface of the housing 4 and has a hole 27 through which a pole can be inserted. When the pole holder 26 is attached to the housing 4, the center of the hole 27 coincides with the position of the virtual image O'.

[0187] By inserting a pole having a ferrule at the lower end into the hole 27, a target device having the same function as the target device 1 shown in Fig. 28 is formed. In the ninth embodiment, the pole holder 26 and the pole 8 form a pointer.

[0188] Fig. 42 shows a target device 21 according to a tenth embodiment. In Fig. 42, the same components as those shown in Fig. 28 are given the same reference numerals and their description will be omitted.

[0189] 42 is a probe 28 configured to be detachable from the rear wall 4a of the housing 4, the probe 28 being provided on an extension of the incident optical axis 3, and the probe 28 having a tip 24. The tip 24 is adapted to coincide with the position of the virtual image O'. The probe 28 functions as a pointing unit that points to the virtual image O'.

[0190] The pole holder 26 and the probe 28 may be fixed to the housing 4, but the pole holder 26 and the probe 28 may have the same mounting structure and be interchangeable depending on the measurement conditions.

[0191] It goes without saying that in the above embodiment, the mirror 5 can be replaced with the reflecting triangular prism 18 shown in the sixth embodiment. Furthermore, it goes without saying that in the above embodiment, the first light-shielding plate 50 and the second light-shielding plate 51 can be replaced with the first hood 52 and the second hood 53.

[0192] According to the present disclosure, the measurement reference point of the reflector can be set to the virtual image position, and further, the measurement reference position exists outside the optical element, and the measurement reference position can be set to the measurement point without offset, further suppressing the generation of stray light.

[0193] Although the embodiments and modifications of the present disclosure have been described above with reference to the drawings, these are merely examples of the present disclosure, and various configurations other than those described above can be adopted.

[0194] Some or all of the above embodiments can be described as, but are not limited to, the following supplementary notes. [Supplementary Notes] 1. A reflector having a deflection optical element arranged on the incident optical axis of measurement light and reflecting the measurement light, and a retroreflector arranged on the reflected optical axis of the deflection optical element, and configured to form a virtual image of the optical center of the retroreflector on an extension of the incident optical axis. 2. The reflector according to paragraph 1 above, having a housing that accommodates the deflection optical element and the retroreflector, and having a window glass on the entrance surface of the housing. 3. The reflector according to paragraph 1 above, wherein the retroreflector is a prism having retroreflectivity. 4. The reflector according to paragraph 1 above, wherein the retroreflector is composed of three mirrors so as to have retroreflectivity. 5. The reflector according to paragraph 1 above, wherein the deflection optical element is a mirror. 6. 1. The reflector according to claim 1, wherein the deflection optical element is a reflecting prism. 7. The reflector according to claim 1, wherein the deflection optical element includes a mirror and a reflecting prism, and is configured to reflect and deflect the measurement light at least twice. 8. The reflector according to claim 6, wherein the reflecting prism has at least two reflecting surfaces, and is configured to reflect and deflect the measurement light at least twice by the at least two reflecting surfaces. 9. A target device comprising the reflector according to any one of claims 1 to 8 and a pole that holds the reflector, the pole having a ferrule at its tip, and the virtual image being positioned on the axis of the pole. 10. The target device according to claim 9, wherein the reflector is provided so as to be movable relative to the pole. 11. A target device comprising a reflector according to any one of items 3 to 8 above and a housing for accommodating said reflector, said housing having a pointer provided on a rear wall thereof, said pointer having a tip for pointing to the position of said virtual image.12. A target device comprising the reflector of any one of items 3 to 8 above, a housing for accommodating the reflector, and a pole with a ferrule at its tip, wherein an engaging protrusion is formed on the rear wall of the housing, a recess is formed on the pole so that the recess can be fitted into the engaging protrusion, and wherein the reflector is supported on the pole by the fitting of the recess and the engaging protrusion, and wherein a virtual image of the reflector is positioned on the axis of the pole. 13. A reflector comprising: a deflecting optical element arranged on the incident optical axis of measurement light and reflecting the measurement light, and a retroreflector arranged on the reflected optical axis of the deflecting optical element and retroreflecting the measurement light, wherein the reflector is arranged to form a virtual image of the optical center of the retroreflector on an extension of the incident optical axis, and wherein a light-shielding portion is provided at at least one of the front end of the reflective surface of the deflecting optical element and the front end of the retroreflector to prevent measurement light from being incident on the retroreflector from outside the normal optical path. 14. The reflector according to claim 13, further comprising a housing for accommodating the deflecting optical element and the retroreflector, the housing having a window glass on its entrance surface. 15. The reflector according to claim 13, further comprising a mirror, the light-blocking portion being a first light-blocking plate provided at the front end of the mirror, and a second light-blocking plate provided at the front end of the retroreflector. 16. The reflector according to claim 13, further comprising a reflector wherein the deflecting optical element is a reflecting triangular prism, the retroreflector is provided on the exit surface of the reflecting triangular prism, the light-blocking portion being a chamfered portion provided at the front end of the reflecting surface of the reflecting triangular prism, and the light-blocking portion being a recess formed at the exit surface of the reflecting triangular prism, at the front end of the retroreflector. 17. A target device comprising a reflector according to any one of items 13 to 16 above and a pole that holds the reflector, the pole having a ferrule at its tip, and the virtual image being positioned on the axis of the pole. 18. The target device according to item 17 above, wherein the reflector is provided movably relative to the pole.19. A target device comprising the reflector of any one of items 13 to 16 above and a housing that accommodates the reflector, wherein an indication portion is provided on the rear wall of the housing, and the indication portion has a tip that indicates the position of the virtual image. 20. The target device described in item 19 above, wherein the indication portion is a protrusion formed on the rear wall of the housing, extends along an extension of the incident optical axis, and has a tip. 21. The target device described in item 19 above, wherein the indication portion is an adapter detachable to the rear wall and a pole inserted into the adapter. 22. The target device described in item 19 above, wherein the indication portion is a probe detachable to the rear wall.

[0195] REFERENCE SIGNS LIST 1 target device 2 reflector 3 incident optical axis 3' reflected optical axis 4 housing 5 mirror 6 corner cube prism 8 pole 15 measuring device 18 reflecting triangular prism 24 tip 25 probe 28 probe 29 pole holder 30 reflector module 31 pole holder 41 reflecting prism 42 deflecting prism 46 mirror 47 mirrored plane-parallel plate 50 first light-shielding plate 51 second light-shielding plate 54 chamfered portion 55a groove

Claims

1. A reflector that is arranged on the incident optical axis of measurement light and has a deflection optical element that reflects the measurement light and a retroreflector that retroreflects the measurement light on the reflected optical axis of the deflection optical element, and is configured to form a virtual image of the optical center of the retroreflector on an extension of the incident optical axis.

2. A reflector according to claim 1, further comprising a housing for accommodating said deflecting optical member and said retroreflector, said housing having a window glass on the entrance surface thereof.

3. The reflector of claim 1, wherein said retroreflector is a prism having retroreflection properties.

4. The reflector of claim 1, wherein said retroreflector is constructed of three mirrors so as to have retroreflectivity.

5. The reflector of claim 1, wherein said deflecting optical element is a mirror.

6. The reflector of claim 1, wherein said deflecting optical element is a reflecting prism.

7. The reflector of claim 1, wherein the deflecting optical member includes a mirror and a reflecting prism, and is configured to reflect and deflect the measurement light at least twice.

8. The reflector according to claim 6, wherein the reflecting prism has at least two reflecting surfaces, and is configured to reflect and deflect the measurement light at least twice by the at least two reflecting surfaces.

9. The reflector of claim 1, wherein a light-shielding portion is provided at least on either the front end of the reflecting surface of the deflecting optical member or the front end of the retroreflector to prevent measurement light from entering the retroreflector from outside the normal optical path.

10. A reflector according to claim 9, further comprising a housing for accommodating said deflection optical member and said retroreflector, said housing having a window glass on the entrance surface.

11. A reflector according to claim 9, wherein the deflecting optical element is a mirror, the light-shielding portion is a first light-shielding plate provided at the front end of the mirror, and the light-shielding portion is a second light-shielding plate provided at the front end of the retro-reflector.

12. A reflector according to claim 9, wherein the deflecting optical element is a reflecting triangular prism, the retroreflector is provided on the exit surface of the reflecting triangular prism, the light-shielding portion is a chamfered portion provided on the front end of the reflecting surface of the reflecting triangular prism, and the light-shielding portion is a recess formed on the exit surface of the reflecting triangular prism at the front end of the retroreflector.

13. A target device comprising a reflector according to any one of claims 1 to 12 and a pole for holding said reflector, said pole having a ferrule at its tip, said virtual image being positioned on the axis of said pole.

14. The targeting device of claim 13, wherein said reflector is movably mounted relative to said pole.

15. A target device comprising a reflector according to any one of claims 1 to 12 and a housing for accommodating said reflector, wherein an indicator is provided on the rear wall of said housing, and said indicator has a tip for indicating the position of said virtual image.

16. The target device according to claim 15, wherein the indicator is a protrusion formed on the rear wall of the housing, extending along the incident optical axis, and having a tip.

17. The target device according to claim 15, wherein said support portion is an adapter detachable from said rear wall and a pole inserted into said adapter.

18. The targeting device of claim 15, wherein said support is a probe detachable from said rear wall.

19. A target device comprising a reflector according to any one of claims 3 to 12, a housing for storing the reflector, and a pole with a ferrule at its tip, wherein an engaging protrusion is formed on the rear wall of the housing, a recess is formed on the pole, and the recess and the engaging protrusion can be fitted together, and the reflector is supported on the pole by the fitting of the recess and the engaging protrusion, and the virtual image of the reflector is positioned on the axis of the pole.

Images