Optical probe and shape measuring device

Abstract

To prevent a measurement error in irradiating an object to be measured with line light to measure the object to be measured.SOLUTION: An optical probe 10 comprises: an irradiation unit 20 that irradiates an object to be measured with line light; and an imaging unit 40 that receives the line light reflected on the object to be measured to pick up an image of the object to be measured with a predetermined exposure time. The irradiation unit 20 has a cylindrical lens 26 that generates the line light, and a light vibration unit 50 that, during the exposure time, irradiates the object to be measured with the line light generated by the cylindrical lens 26 while vibrating the line light in a lengthwise direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an optical probe and a shape measuring device. [Background technology]

[0002] A non-contact optical probe is used in shape measurement devices to measure the cross-sectional shape of a measurement object by a light-section method based on the triangulation principle. The optical probe irradiates a line of light onto the measurement object and captures an image of the measurement object based on the light reflected from the surface of the measurement object (see Patent Document 1 below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5869281 Summary of the Invention [Problem to be solved by the invention]

[0004] In an optical probe, a linear line of light is projected onto the object to be measured, but due to errors caused by lens components included in the optical probe, the distribution of the line of light on the surface of the object to be measured may be wavy rather than linear. In this case, the imaging unit captures a wavy image, resulting in an error in measuring the shape of the object to be measured.

[0005] The present invention has been made in consideration of these points, and has an object to suppress measurement errors when measuring an object by irradiating a line of light. [Means for solving the problem]

[0006] In a first aspect of the present invention, there is provided an optical probe comprising an irradiation unit which irradiates a line light onto a measurement object, and an imaging unit which receives the line light reflected by the measurement object and captures an image of the measurement object within a predetermined exposure time, wherein the irradiation unit has a light generation unit which generates the line light, and a light vibration unit which irradiates the line light generated by the light generation unit onto the measurement object while vibrating it in the longitudinal direction during the exposure time.

[0007] The optical vibration unit may irradiate the measurement object with the line of light while moving the line of light back and forth in the length direction at least once during the exposure time.

[0008] The light vibration unit may irradiate the line light having a predetermined period in the length direction onto the measurement object while vibrating the line light so as to shift the line light by ½ or more of the period.

[0009] The light vibration unit may also have an oscillating mirror that oscillates about an axis perpendicular to the length direction, and the line light may be vibrated in the length direction by oscillating the oscillating mirror.

[0010] The oscillating mirror may oscillate within a predetermined angle range at least once during the exposure time.

[0011] In addition, the irradiation unit may further include a light source that emits laser light, the light generation unit may transform the laser light into the line light, and the light vibration unit may have an actuator that moves the light source back and forth in the length direction, and the line light may be vibrated in the length direction by moving the light source back and forth.

[0012] The light vibration unit may also have an actuator that reciprocates a lens serving as the light generation unit in the longitudinal direction, and the line of light may be vibrated in the longitudinal direction by reciprocating the lens.

[0013] The optical vibration unit may have a rotating mirror including a plurality of reflective surfaces capable of reflecting the line of light, and may vibrate the line of light in the length direction by rotating the rotating mirror.

[0014] The imaging device may further include a control unit configured to control exposure of the imaging unit and vibration of the line light in the length direction by the light vibration unit so as to be synchronized with each other.

[0015] In a second aspect of the present invention, there is provided a shape measuring device including an optical probe having an irradiation unit that irradiates a line light onto a measurement object, and an imaging unit that receives the line light reflected by the measurement object and captures an image of the measurement object over a predetermined exposure time, and a calculation unit that calculates a shape of the measurement object based on an output of the imaging unit, wherein the irradiation unit has a light generation unit that generates the line light, and a light vibration unit that irradiates the line light generated by the light generation unit onto the measurement object while vibrating it in the longitudinal direction during the exposure time. Effect of the Invention

[0016] According to the present invention, it is possible to suppress measurement errors when measuring an object by irradiating it with a line of light. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a schematic diagram for explaining the configuration of an optical probe 10 according to a first embodiment. [Diagram 2] FIG. 2 is a block diagram for explaining the configuration of an optical probe 10. [Diagram 3] 1 is a schematic diagram for explaining the configuration of an optical probe 10. FIG. [Figure 4] 2 is a schematic diagram for explaining the configuration of an optical probe 110 according to a comparative example. FIG. [Diagram 5] 10 is a schematic diagram for explaining an image formed on an imaging section 40 in a comparative example. FIG. [Figure 6]2 is a schematic diagram for explaining an image formed on an imaging section 40 in the present embodiment. FIG. [Figure 7] 4 is a schematic diagram for explaining the oscillation of an oscillating mirror 54. FIG. [Figure 8] FIG. 1 is a schematic diagram for explaining the configuration of a shape measuring device 1. [Figure 9] FIG. 4 is a schematic diagram for explaining the configuration of an optical probe 10 according to a second embodiment. [Figure 10] FIG. 11 is a schematic diagram for explaining the configuration of an optical probe 10 according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] <First embodiment> (Optical probe configuration) The configuration of the optical probe according to the first embodiment will be described with reference to FIGS. 1 to 3. FIG.

[0019] Fig. 1 is a schematic diagram for explaining the configuration of an optical probe 10 according to a first embodiment. Fig. 2 is a block diagram for explaining the configuration of the optical probe 10. Fig. 3(a) shows the optical probe 10 of Fig. 1 as viewed from the length direction of the line light L (see Fig. 1), and Fig. 3(b) shows the optical probe 10 as viewed from the normal direction (see Fig. 1) of the light section (Fig. 1).

[0020] The optical probe 10 is used to measure the cross-sectional shape of a light-cut surface of the measurement object W (in FIG. 1, the shape of a step portion of the measurement object W). Specifically, the optical probe 10 irradiates the measurement object W with a line light L, and captures an image of the measurement object W based on the light reflected from the surface of the measurement object W. As shown in FIGS. 1 and 2, the optical probe 10 has an irradiation unit 20, an imaging lens 30, an imaging unit 40, an optical vibration unit 50, and a probe control unit 70.

[0021] The irradiation unit 20 irradiates the measurement object W with a line light L. Specifically, the irradiation unit 20 transforms laser light into the line light L and irradiates the measurement object W with the line light L. As shown in FIG. 1, the irradiation unit 20 has a light source 22, a collimator lens 24, and a cylindrical lens 26.

[0022] The light source 22 is composed of, for example, an LD (Laser Diode) or the like, and generates and emits laser light. The light source 22 emits laser light of a predetermined wavelength. The collimator lens 24 converts the laser light emitted from the light source 22 into parallel light. The collimator lens 24 is a convex lens in this embodiment. The cylindrical lens 26 transforms the parallel light (laser light) from the collimator lens 24 into a line-shaped line light L. In this embodiment, the cylindrical lens 26 corresponds to a light generating unit that generates the line light L.

[0023] The imaging lens 30 forms an image of the line light L, which is reflected light from the measurement target W, on the imaging surface of the imaging unit 40. The imaging lens 30 here is a convex lens.

[0024] The imaging unit 40 is an image sensor such as a CMOS, and captures an image of the measurement object W. The imaging unit 40 receives the line light L reflected by the measurement object W, and captures an image of the measurement object W for a predetermined exposure time. That is, the imaging unit 40 captures an image of a light distribution showing a cross-sectional shape of the measurement object W on a light-section surface. As shown in FIG. 1, the imaging unit 40 is disposed in a direction that forms a predetermined angle with respect to the irradiation direction of the measurement object W irradiated from the irradiation unit 20, and receives light reflected along the surface shape of the measurement object W from the predetermined angle.

[0025] Incidentally, although a linear line light L is irradiated onto the measurement object W, an event may occur in which the distribution of the line light L on the surface of the measurement object W is undulating rather than linear due to an error or the like caused by a lens component included in the optical probe 10. Specifically, the distribution of the line light L undulates in the normal direction of the light section. In this case, the imaging unit 40 captures an undulating image, causing a measurement error in the shape of the measurement object W.

[0026] Fig. 4 is a schematic diagram for explaining the configuration of an optical probe 110 according to a comparative example. The optical probe 110 according to the comparative example has an irradiation unit 20, an imaging lens 30, and an imaging unit 40, similar to the optical probe 10 described above. On the other hand, the optical probe 110 does not have the optical vibration unit 50 of the optical probe 10. In the comparative example, as shown in Fig. 4, the distribution A of the line light L undulates in the normal direction by an error e.

[0027] FIG. 5 is a schematic diagram for explaining an image formed on the imaging unit 40 in the comparative example. The horizontal axis of FIG. 5 indicates the horizontal direction of the image sensor which is the imaging unit 40, and the vertical axis of FIG. 5 indicates the vertical direction of the image sensor. Here, the part surrounded by the dashed line is the image 120 of a predetermined width formed on the imaging unit 40. Also, the peak part 122 of the light distribution of the image 120 indicates the cross-sectional shape of the measurement object W, and is shown here by a dashed line. FIG. 5(a) shows the image 120 in an ideal case where there is no error due to the lens parts. In an ideal case, the peak part 122 is a straight line. On the other hand, if an error due to the lens parts occurs in the optical probe 110 according to the comparative example and the distribution of the line light L undulates in the normal direction as shown in FIG. 4, the image 120 captured by the imaging unit 40 has a wavy shape as shown in FIG. 5(b). Accordingly, the peak part 122 also has a wavy shape, and the measurement error of the measurement object W becomes large.

[0028] In contrast, in the optical probe 10 of this embodiment, the irradiation unit 20 is provided with an optical vibration unit 50 in order to suppress measurement errors. The optical vibration unit 50 vibrates the line light L to be irradiated onto the measurement object W. Specifically, the optical vibration unit 50 irradiates the line light L onto the measurement object W while vibrating it in the length direction during the exposure time of the imaging unit 40. As a result, the imaging unit 40 images the line light L vibrating during the exposure time, and the image formed on the imaging surface of the imaging unit 40 has undulations in the normal direction averaged out.

[0029] Fig. 6 is a schematic diagram for explaining an image formed on the imaging section 40 in this embodiment. The image 130 formed on the imaging section 40 shown in Fig. 6 has averaged undulations compared to the image 120 shown in Fig. 5(b). In addition, the undulations of the peak portion 132 are also reduced, so that measurement errors of the measurement object W can be suppressed.

[0030] The optical vibration unit 50 irradiates the measurement object W with the line light L while moving it back and forth in the length direction during the exposure time of the imaging unit 40. However, without being limited thereto, the optical vibration unit 50 may irradiate the measurement object W with the line light L while moving it back and forth in the length direction multiple times during the exposure time of the imaging unit 40. That is, the optical vibration unit 50 moves the line light at least once back and forth in the length direction during the exposure time. This makes it easier to average out random swells of the line light L in the second direction.

[0031] The optical vibration unit 50 irradiates the measurement object W with the line light L having a predetermined period in the length direction while vibrating the line light L so as to shift by 1 / 2 or more of the period. For example, the optical vibration unit 50 vibrates the line light L so as to shift by 1 / 2 of the period T shown in FIG. 5(b). By shifting by 1 / 2 or more of the period in this manner, it becomes easier to average out the undulations of the line light L in the second direction. The above-mentioned predetermined period may be determined in advance by experiment or the like and set.

[0032] As shown in FIG. 1, the optical vibration unit 50 includes a flat mirror 52 and an oscillating mirror 54. The flat mirror 52 reflects the line light L from the cylindrical lens 26 toward the oscillating mirror 54. The flat mirror 52 reflects the line light L by 90° here. The flat mirror 52 is a fixed mirror.

[0033] The oscillating mirror 54 is a mirror that directs the line light L reflected from the flat mirror 52 toward the measurement object W. Here, the oscillating mirror 54 reflects the line light L vertically downward. The oscillating mirror 54 oscillates the line light L traveling toward the measurement object W by oscillating. The oscillating mirror 54 oscillates about an axis C (see FIG. 1) in a normal direction perpendicular to the length direction of the line light L. For example, the oscillating mirror 54 oscillates once within a predetermined angle range (e.g., several degrees) during the exposure time. However, without being limited thereto, the oscillating mirror 54 may oscillate multiple times within a predetermined angle range during the exposure time. That is, the oscillating mirror 54 oscillates at least once during the exposure time.

[0034] Fig. 7 is a schematic diagram for explaining the oscillation of the oscillating mirror 54. The oscillating mirror 54 oscillates by rotating between a first position shown in Fig. 7(a) and a second position shown in Fig. 7(b). The oscillating mirror 54 oscillates between the first position and the second position, causing the line light L to vibrate in the length direction. Note that as the oscillating mirror 54, a MEMS (Micro Electro Mechanical Systems) scanner, a galvano scanner, a resonant scanner, or the like is used.

[0035] The probe control unit 70 controls the operation of the optical probe 10. The probe control unit 70 controls the irradiation of laser light by the irradiation unit 20 and the capture of an image of the measurement target W by the imaging unit 40.

[0036] The probe control unit 70 controls the vibration of the line light L by the optical vibration unit 50. For example, the probe control unit 70 vibrates the distribution of the line light L in the length direction at high speed by oscillating the oscillating mirror 54 of the optical vibration unit 50 at high speed. In addition, the probe control unit 70 controls the exposure of the imaging unit 40 and the vibration of the line light L in the length direction by the optical vibration unit 50 to be synchronized. For example, the probe control unit 70 controls the operation of the imaging unit 40 and the optical vibration unit 50 so that the conditions of the exposure time of the imaging unit 40 and the oscillation angle of the oscillating mirror 54 of the optical vibration unit 50 are constant. This allows the imaging unit 40 to capture an image of the measurement target W when the line light L vibrates.

[0037] (Configuration of shape measuring device) The configuration of a shape measuring device 1 including the optical probe 10 having the above-described configuration will be described with reference to FIG.

[0038] Fig. 8 is a schematic diagram for explaining the configuration of the shape measuring apparatus 1. The shape measuring apparatus 1 measures the shape of a workpiece, which is a measurement target W, based on the detection result of the imaging unit 40 of the optical probe 10. The shape measuring apparatus 1 is, for example, a three-dimensional shape measuring apparatus that measures the three-dimensional shape of the workpiece. As shown in Fig. 8, the shape measuring apparatus 1 includes the optical probe 10, a moving mechanism 80, and a control device 90.

[0039] The configuration of the optical probe 10 has been described above, and therefore detailed description thereof will be omitted here. The movement mechanism 80 moves the optical probe 10. For example, the movement mechanism 80 moves the optical probe 10 in three axis directions that are perpendicular to one another.

[0040] The control device 90 controls the operation of the optical probe 10 (specifically, the irradiation unit 20, the imaging unit 40, and the optical vibration unit 50) and the movement mechanism 80. In addition, the control device 90 performs measurement using the optical probe 10 while moving the optical probe 10 using the movement mechanism 80, for example. The control device 90 includes a storage unit 92 and a control unit 94.

[0041] The storage unit 92 includes, for example, a Read Only Memory (ROM) and a Random Access Memory (RAM). The storage unit 92 stores various data and programs executable by the control unit 94. For example, the storage unit 92 stores the results of measurement by the optical probe 10.

[0042] The control unit 94 is, for example, a CPU (Central Processing Unit). The control unit 94 executes a program stored in the storage unit 92 to control the operation of the optical probe 10 via the probe control unit 70. Specifically, the control unit 94 controls the irradiation of the measurement object W with laser light by the light source 22 of the irradiation unit 20. The control unit 94 also acquires the output of the imaging unit 40 and calculates the shape of the measurement object W. In this embodiment, the control unit 94 functions as a calculation unit that calculates the shape of the measurement object W based on the output of the imaging unit 40.

[0043] (Effects of the first embodiment) In the optical probe 10 of the first embodiment, the irradiation section 20 has a light vibration section 50 that irradiates the measurement object W with a line of light L while vibrating the line of light L in the length direction during the exposure time of the imaging section 40. As a result, even if an error caused by the lens components of the optical probe 10 causes the line light L to undulate in the normal direction on the surface of the object to be measured W, the image formed on the imaging surface of the imaging unit 40 has averaged undulations by imaging the oscillating line light L during the exposure time. As a result, measurement errors of the object to be measured W caused by undulations of the line light L in the normal direction can be suppressed.

[0044] <Second embodiment> In the second embodiment, the configuration of the optical vibration unit 50 is different from that of the first embodiment, but the other configurations are similar to those of the first embodiment.

[0045] 9 is a schematic diagram for explaining the configuration of an optical probe 10 according to the second embodiment. An optical vibration unit 50 of the second embodiment has an actuator 60 provided near the light source 22, instead of the flat mirror 52 and the oscillating mirror 54 of the first embodiment.

[0046] The actuator 60 reciprocates the irradiation unit 20 and the light source 22 in the length direction of the line light L. The light source 22 reciprocates between a first position shown in FIG. 9(a) and a second position shown in FIG. 9(b) by the actuator 60. On the other hand, the collimator lens 24 and the cylindrical lens 26 of the irradiation unit 20 do not move. Therefore, when the light source 22 is located at the first position, the laser light is irradiated onto the measurement object W as shown in FIG. 9(a), and when the light source 22 is located at the second position, the laser light is irradiated onto the measurement object W as shown in FIG. 9(b). As can be seen by comparing FIG. 9(a) and FIG. 9(b), when the position of the light source 22 is displaced, the position of the line light L in the length direction is also displaced. Therefore, when the light source 22 reciprocates, the line light L vibrates in the length direction.

[0047] In the second embodiment, the optical vibration unit 50 also vibrates the line light L in the length direction by using the actuator 60 to move the light source 22 back and forth in the length direction of the line light L during the exposure time of the imaging unit 40. Therefore, the imaging unit 40 captures an image of the measurement object W when the line light L vibrates. As a result, even if an event occurs in which the line light L undulates in the normal direction on the surface of the measurement object W, the image formed on the imaging surface of the imaging unit 40 has the undulations averaged. As a result, it is possible to suppress measurement errors of the measurement object W caused by the undulation of the line light L in the normal direction.

[0048] (Modification) In the above, the actuator 60 reciprocates the light source 22 to vibrate the line light L, but this is not limited thereto. The actuator 60 may reciprocate the collimator lens 24 and the cylindrical lens 26 in the length direction of the line light L, instead of the light source 22. For example, the actuator 60 reciprocates the collimator lens 24 and the cylindrical lens 26 between two positions, as in the light source 22 shown in FIG. 9. The reciprocating movement of the collimator lens 24 and the cylindrical lens 26 causes the line light L to vibrate in the length direction.

[0049] Even in the modified example, the optical vibration unit 50 causes the actuator 60 to reciprocate the collimator lens 24 and the cylindrical lens 26 during the exposure time of the imaging unit 40, so that the line light L vibrates in the length direction. As a result, the imaging unit 40 captures an image of the measurement object W when the line light L vibrates.

[0050] <Third embodiment> In the third embodiment, the configuration of the optical vibration unit 50 is different from that of the first embodiment, but the other configurations are similar to those of the first embodiment.

[0051] 10 is a schematic diagram for explaining the configuration of an optical probe 10 according to the third embodiment. An optical vibration unit 50 of the third embodiment has a rotating mirror 65 instead of the oscillating mirror 54 of the first embodiment.

[0052] The rotating mirror 65 rotates in the direction of the arrow shown in Fig. 10. The rotating mirror 65 directs the line light L reflected from the flat mirror 52 toward the measurement object W. The rotating mirror 65 is, for example, a polygon mirror, and includes a plurality of reflective surfaces 67 capable of reflecting the line light L. As the rotating mirror 65 rotates, the line light L is reflected by the reflective surfaces 67, causing the line light L to oscillate in the longitudinal direction.

[0053] In the third embodiment, the optical vibration unit 50 also rotates the rotating mirror 65 during the exposure time of the imaging unit 40 to vibrate the line light L in the length direction. Therefore, the imaging unit 40 captures an image of the measurement object W when the line light L vibrates. As a result, even if an event occurs in which the line light L undulates in the normal direction on the surface of the measurement object W, the image formed on the imaging surface of the imaging unit 40 has the undulations averaged. As a result, it is possible to suppress measurement errors of the measurement object W caused by the undulation of the line light L in the normal direction.

[0054] Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. For example, all or part of the device can be configured by distributing or integrating functionally or physically in any unit. In addition, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effect of the new embodiment resulting from the combination combines the effect of the original embodiment. [Explanation of symbols]

[0055] 1 Shape measuring device 10 Optical Probe 20 Irradiation unit 22 Light source 24 Collimator lens 26 Cylindrical Lens 40 Imaging unit 50 Optical vibration part 54 Swinging Mirror 60 Actuator 65 Rotating Mirror 66 Reflective surface 70 Probe control section 94 Control Unit L Line Light W Measurement object

Claims

1. an irradiation unit that irradiates a line of light onto an object to be measured; an imaging unit that receives line light reflected by the measurement object and captures an image of the measurement object for a predetermined exposure time; Equipped with The irradiation unit includes: A light generating unit that generates the line light; a light vibration unit that irradiates the line light generated by the light generation unit onto the measurement object while vibrating the line light in a longitudinal direction during the exposure time; having The optical probe is configured such that the light vibration unit irradiates the line of light having a predetermined period in the length direction onto the object to be measured while vibrating the line of light so as to shift the line of light by at least 1 / 2 of the period.

2. The optical vibration unit irradiates the measurement object with the line light while moving the line light back and forth in the length direction at least once during the exposure time. The optical probe according to claim 1 .

3. The light vibration unit has a swing mirror that swings about an axis perpendicular to the length direction, and vibrates the line light in the length direction by swinging the swing mirror.

3. The optical probe according to claim 1 or 2.

4. the oscillating mirror oscillates at least once within a predetermined angle range during the exposure time; The optical probe according to claim 3 .

5. The irradiation unit further includes a light source that emits laser light, The light generating unit transforms the laser light into the line light, The light vibration unit has an actuator that reciprocates the light source in the length direction, and vibrates the line light in the length direction by reciprocating the light source.

3. The optical probe according to claim 1 or 2.

6. The light vibration unit has an actuator that reciprocates a lens serving as the light generation unit in the length direction, and vibrates the line light in the length direction by reciprocating the lens.

3. The optical probe according to claim 1 or 2.

7. The optical vibration unit has a rotating mirror including a plurality of reflective surfaces capable of reflecting the line light, and vibrates the line light in the length direction by rotating the rotating mirror.

3. The optical probe according to claim 1 or 2.

8. A control unit is further provided that controls the exposure of the imaging unit and the vibration of the line light in the length direction by the light vibration unit so as to be synchronized. The optical probe according to any one of claims 1 to 7.

9. An optical probe including an irradiation unit that irradiates a line light onto a measurement object, and an imaging unit that receives the line light reflected by the measurement object and captures an image of the measurement object for a predetermined exposure time; A calculation unit that calculates a shape of the measurement object based on an output of the imaging unit; Including, The irradiation unit includes: A light generating unit that generates the line light; a light vibration unit that irradiates the line light generated by the light generation unit onto the measurement object while vibrating the line light in a longitudinal direction during the exposure time; having The light vibration unit irradiates the line light having a predetermined period in the length direction onto the object to be measured while vibrating the line light so as to shift by 1 / 2 or more of the period.

Images