JP2020076695A - Profile measuring device - Google Patents

Abstract

To more accurately obtain a profile of a surface of an object to be measured.SOLUTION: A profile measuring device comprises: a mirror that deflects a planar measurement light, wherein the mirror can change a reflection direction of the planar measurement light; a drive unit that changes a reflection direction of the mirror by driving the mirror; a detection unit that detects vibration from the outside to the mirror or vibration that occurs in the mirror until an angle of the mirror stabilizes at a target angle when the angle of the mirror is changed; and a control unit that controls the drive unit so that the vibration of the mirror converges based on the detection result of the detection unit.SELECTED DRAWING: Figure 15

Description

  The present invention relates to a displacement measuring device that measures a profile of a measuring object.

  The displacement measuring device measures the three-dimensional shape of the measuring object using the principle of triangulation. According to Patent Document 1, the displacement measuring device irradiates the surface of the measurement target with strip-shaped measurement light (planar measurement light) so as to cut the measurement target, and reflects it from the surface of the measurement target. Light is received by a light receiving element to obtain height information (light cutting method). In Patent Literature 1, the measurement light in a stationary state is scanned with the measurement light in a direction orthogonal to the extending direction of the measurement light, and the three-dimensional shape of the measurement target is measured.

JP 2000-193428 A

  The displacement measuring device can scan the surface of the measuring object with the measuring light by deflecting the measuring light by the scanning mirror. It is necessary to accurately control the angle of the scanning mirror in order to irradiate the target position with the measurement light. Further, the scanning mirror must be stationary while the measuring light is radiated on the aimed position. However, if the angle of the scanning mirror is changed stepwise by a predetermined angle, unintended vibration will occur in the scanning mirror when changing from one angle to the next. Further, vibration propagates from the outside of the displacement measuring device, and the scanning mirror vibrates. Therefore, an object of the present invention is to more accurately obtain the profile of the surface of the measuring object by reducing unintended vibration.

The present invention is, for example,
A light source that outputs light,
A conversion optical system that converts the light output from the light source into a planar measurement light and outputs the converted light.
A light guide optical system that guides the planar measurement light emitted from the conversion optical system so as to be directed toward the surface of a measurement object,
A light receiving unit for receiving the reflected light from the measurement object,
Based on the principle of triangulation, profile acquisition for acquiring a profile that is an aggregate of heights of respective reflection positions of the planar measurement light in the measurement object according to the incident position of the reflected light in the light receiving unit Part and
The light guide optical system,
A mirror for deflecting the planar measurement light, the mirror being capable of changing the reflection direction of the planar measurement light,
A drive unit that changes the reflection direction of the mirror by driving the mirror,
Vibration from the outside with respect to the mirror, or a detection unit that detects vibration occurring in the mirror until the angle of the mirror stabilizes at a target angle when the angle of the mirror is changed,
A profile measuring device comprising: a control unit that controls the drive unit so that vibration of the mirror converges based on a detection result of the detection unit.

  According to the present invention, since unintended vibration is reduced, the profile of the surface of the measuring object can be obtained more accurately.

It is a figure explaining operation of a displacement measuring device. It is the perspective view which looked at the sensor head from the lower part. It is a state in which the side cover of the sensor head is removed, and is a partially transparent view of the internal structure of the sensor head. It is a side view which removed the side cover of a sensor head. It is an exploded perspective view of an optical system of a sensor head. It is a block diagram of a displacement measuring device. 7A and 7B are diagrams for explaining the line mode. FIG. 8A and FIG. 8B are diagrams for explaining the scan mode. It is a schematic diagram explaining the measurement principle of the displacement by a displacement measuring device. It is a schematic diagram explaining the measurement principle of the displacement by a displacement measuring device. It is a figure explaining an amplifier. 7 is a flowchart showing a scan mode setting process. It is a flow chart which shows the operation processing of scan mode. It is a flowchart which shows the setting process of a line mode. It is a flowchart which shows the driving process of a line mode. It is a figure explaining a mirror control part. It is a circuit diagram of a mirror control unit. It is a figure explaining a mirror control part. It is a circuit diagram of a mirror control unit. It is a figure explaining a mirror control part. It is a circuit diagram of a mirror control unit.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following description of the preferred embodiments is essentially merely an example, and does not limit the present invention, its application, or its application.

  FIG. 1 schematically shows the displacement measuring device 1 according to the embodiment of the present invention in operation. The displacement measuring device 1 is a device or system for measuring the displacement of the measurement object W at a predetermined position, and may be simply called a displacement meter, or may be called a range finder or a height displacement meter. .. Further, as will be described later in detail, when the scan mode of scanning the measurement light is used, the displacement measuring device 1 is a device in which a displacement gauge is added to the image sensor or a measurement location of the displacement gauge is variable. May be called. Further, in this embodiment, since the displacement of each part of the measuring object W can be measured, the displacement measuring device 1 may be called a three-dimensional measuring system. Also, in this embodiment, displacement measurement may be referred to as height measurement.

  FIG. 1 shows a case where the measurement object W is being conveyed by a conveyance device such as a conveyor belt conveyor B, that is, a case where the measurement object W is moving. However, the measuring object W may be stationary. Further, the number of measurement objects W that can be measured at one time is one or more, and the displacements of the plurality of measurement objects W at predetermined positions may be measured at one time. The type of the measuring object W is not particularly limited.

(Overall configuration of the displacement measuring device 1)
In the example shown in FIG. 1, the displacement measuring device 1 includes a plurality of sensor heads 2, a slave unit amplifier 3, a master unit amplifier 4, and a monitor device 5A or a personal computer 5B as a setting device. The sensor head 2 may be one, and the minimum configuration when the setting device 5 is unnecessary is one sensor head 2 and one master amplifier 4. A system in which the slave unit amplifier 3 and the master unit amplifier 4 are integrated may be used.

  The first sensor head 2 is connected to the slave unit amplifier 3 via the connection line 2a and is configured to be capable of mutual communication. The second sensor head 2 is connected to the base unit amplifier 4 via the connection line 2a and is configured to be capable of mutual communication. The slave unit amplifier 3 cannot operate alone, but is connected to the master unit amplifier 4 and can be operated by receiving power supply from the master unit amplifier 4. Further, the slave unit amplifier 3 and the master unit amplifier 4 are configured to be able to communicate with each other. It is possible to connect a plurality of slave unit amplifiers 3 to the master unit amplifier 4. In the present embodiment, only the master unit amplifier 4 is provided with the Ethernet (registered trademark) connector, and both the master unit amplifier 4 and the slave unit amplifier 3 are connected to the monitor device 5A or the personal computer via the Ethernet (registered trademark) connector. It is possible to communicate with 5B. Note that the slave unit amplifier 3 may be omitted, or the function of the slave unit amplifier 3 may be incorporated into the master unit amplifier 4 to form one amplifier. Further, the function of the slave unit amplifier 3 and the function of the master unit amplifier 4 may be incorporated in the sensor head 2. In this case, the function of the slave unit amplifier 3 and the master unit amplifier 4 are omitted. Further, the above-mentioned Ethernet (registered trademark) connector may be provided not only in the master unit amplifier 4 but also in the slave unit amplifier 3.

  The external device 6 can be, for example, a programmable logic controller (PLC). The PLC is a control device for sequence-controlling the conveyor belt conveyor B and the displacement measuring device 1. The PLC may be a general-purpose device.

  During its operation, the displacement measuring device 1 receives a measurement start trigger signal that defines the measurement start timing from the external device 6 via the connection line 6a. Then, the displacement measuring device 1 measures the displacement and determines the quality based on the measurement start trigger signal. The result can be configured to be transmitted to the external device 6 via the connection line 6a. Note that FIG. 1 is merely an example showing the system configuration of the displacement measuring device 1. The present invention is not limited to this, and the master unit amplifier 4 and the slave unit amplifier 3 may have IO input / output and may be directly connected to the external device 6. In this case, physical signals such as a trigger signal and a result output signal are exchanged with the external device 6 from the external device 6. Further, the master unit amplifier 4 may be provided with an analog output. Further, the master unit amplifier 4 and the slave unit amplifier 3 may communicate with the external device 6 via the Ethernet (registered trademark) connector described above. In this case, communication may be performed using various known communication protocols such as Ethernet (registered trademark) / IP and PROFINET.

  During operation of the displacement measuring device 1, the measurement start trigger signal is repeatedly input and the result is output between the displacement measuring device 1 and the external device 6 via the connection line 6a. As described above, the input of the measurement start trigger signal and the output of the result may be performed via the connection line 6a between the displacement measuring device 1 and the external device 6, or other communication line (not shown). You may go through. For example, a sensor (not shown) for detecting the arrival of the measuring object W is directly connected to the displacement measuring device 1, and a measurement start trigger signal is input from the sensor to the displacement measuring device 1. Good. The displacement measuring device 1 can also be configured to operate by an internally generated internal trigger. As described above, the displacement measuring device 1 may have a mode of periodically issuing an internal trigger.

  One of the monitor device 5A and the personal computer 5B is connected to the master unit amplifier 4 via the connection line 5a and is configured to be capable of mutual communication. However, both the monitor device 5A and the personal computer 5B are the master unit. It may be connected to the amplifier 4. The monitor device 5A and the personal computer 5B are operation devices for performing various settings and operations of the displacement measuring device 1, and also include images taken by the sensor head 2, processed images, various measurement values, measurement results, determination results, etc. Is also a display device for displaying. The monitor device 5A is a dedicated product, but the personal computer 5B can be a general-purpose product. Needless to say, a general-purpose product such as a so-called programmable display may be used as the monitor device 5A.

  Communication between the sensor head 2 and the slave unit amplifier 3 or the master unit amplifier 4, communication between the master unit amplifier 4 and the monitor device 5A or the personal computer 5B, communication between the master unit amplifier 4 and the external device 6. May be wired or wireless. The communication unit of the base unit amplifier 4 is not particularly limited, but examples thereof include EtherNet / IP, PROFINET, CC-Link, DeviceNet, EtherCAT, PROFIBUS, BCD, RS-232C.

(Monitor device 5A and personal computer 5B)
The monitor device 5A and the personal computer 5B each include a display unit 8 including a display device such as a liquid crystal display or an organic EL display. As will be described later, the display unit 8 can display an image captured by the sensor head 2, an image generated by the slave unit amplifier 3 or the master unit amplifier 4, various interfaces, and the like. ..

  The monitor device 5A includes a touch panel type input unit 9 and is configured to be able to receive the input operation of the user touching the display unit 8 and the input operation. The personal computer 5B includes an input unit 9 including a keyboard, a mouse, a touch pad, a touch panel, and the like, and is configured to be able to receive an input operation similarly to the monitor device 5A. The touch operation may be, for example, a pen operation or a finger operation.

(Structure of sensor head 2)
FIG. 2 is a perspective view of the sensor head 2. The sensor head 2 has a housing 50. An end wall portion 51 is provided on a surface facing the measurement object W among the plurality of surfaces forming the housing 50. The end wall portion 51 extends in the longitudinal direction of the housing 50. The end wall portion 51 has a light projecting window 51a through which the measuring light emitted from the light projecting module 10 (FIG. 3 and the like) exits, and a light receiving window 51b through which the illumination light reflected from the measuring object W enters. There is. The light projecting window 51a and the light receiving window 51b are covered with a transparent member. Illumination light from the illumination unit 30 is emitted from the light receiving window 51b. Further, the “transparent member” here may be a bandpass filter. In short, any member such as a laser or an LED may be used as long as it does not block the wavelength of the measurement light. Further, the light projecting window 51a is an example of a “light projecting window section”, and the light receiving window 51b is an example of a “light receiving window section”. The light projecting window 51a and the light receiving window 51b may be separated or may be integrated. For example, the member functioning as the light projecting window 51a and the member functioning as the light receiving window 51b may be two independent members. In addition, a part of one light-transmitting member may function as the light projecting window 51a, and another part of the member may function as the light receiving window 51b.

  As shown in FIGS. 3 to 5, the housing 50 irradiates the measuring object W with the projecting module 10, the angle detection sensor 22, and the measuring object with uniform illumination light. The illuminating unit 30 and the measuring light receiving unit 40 that receives the measuring light reflected from the measuring object W are housed. 2 to 5 define the vertical direction of the sensor head 2, this is for convenience of description. The upward direction does not limit the posture of the sensor head 2 during operation. The sensor head 2 may be used in any orientation and orientation as long as the measurement target W can be measured.

(Structure of housing 50)
As shown in FIGS. 2 to 4, the housing 50 has an elongated shape as a whole. The light projecting module 10 is fixed to the housing 50 in a state of being displaced to one side in the longitudinal direction inside the housing 50. The one side in the longitudinal direction of the housing 50 is the right side in FIG. The illumination unit 30 and the measurement light receiving unit 40 are fixed to the housing 50 in a state of being deviated to the other side in the longitudinal direction inside the housing 50. The other side in the longitudinal direction of the housing 50 is the left side in FIG.

(Structure of the light projecting module 10)
As shown in FIGS. 3 to 5, the light projecting module 10 has a light projecting section 10a, a MEMS mirror 15 as a scanning section, and a modularization member 10b to which these are mounted. The light projecting unit 10a includes a laser 12 as a measurement light source, and a collimator lens 13 and a cylindrical lens 14 on which light from the laser 12 is incident. The light projecting unit 10a generates a strip-shaped measuring light (planar light beam) extending in the first direction shown in FIG. When the strip-shaped measuring light is incident on the plane, the beam spot of the measuring light formed on the plane looks like a line. Therefore, the strip-shaped measurement light is sometimes called line light. The measurement light source may be a light source other than the laser 12.

  The laser 12, the collimator lens 13, and the cylindrical lens 14 are fixed to the modularization member 10b, and their relative positional relationship is maintained. The collimator lens 13 is arranged closer to the laser 12 than the cylindrical lens 14. The collimator lens 13 is a lens for collimating the light beam of the measurement light emitted from the laser 12. The cylindrical lens 14 is arranged so as to have a major axis in the first direction, and is a lens for receiving the measurement light emitted from the collimator lens 13 and generating long strip-shaped measurement light in the first direction. .. Therefore, the measurement light output from the laser 12 is collimated by passing through the collimator lens 13, and then is incident on the cylindrical lens 14 to become a strip-shaped measurement light long in the first direction. A diaphragm member 16 is disposed between the collimator lens 13 and the cylindrical lens 14. The collimator lens 13, the cylindrical lens 14, and the diaphragm member 16 are examples of a light projecting lens. The configuration of the light projecting lens is not limited to this.

(Structure of MEMS mirror 15)
The MEMS mirror 15 is a member configured to scan the measurement light emitted from the cylindrical lens 14 of the light projecting unit 10a in a second direction (eg, FIG. 3) intersecting the first direction. In this embodiment, the second direction is orthogonal to the first direction, but the present invention is not limited to this, and the intersection angle between the first direction and the second direction can be set arbitrarily. In FIG. 1, the first direction may be the width direction of the conveyor belt conveyor B and the second direction may be the conveyor direction of the conveyor belt conveyor B, or vice versa.

  The MEMS mirror 15 has a scanning mirror 15c capable of scanning the measurement light in the second direction, and a drive unit 15b for moving the scanning mirror 15c. The drive unit 15b is an electromagnet (coil) that acts on the permanent magnet provided on the mirror 15c. An electromagnet may be provided on the mirror 15c. The MEMS mirror 15 is fixed to the modularization member 10b so that the scanning mirror 15c faces the light emission surface of the cylindrical lens 14. MEMS refers to Micro Electro Mechanical Systems, which are so-called micro electro mechanical systems. By using this micro electro mechanical system, it is possible to change the angle of the scanning mirror 15c, that is, the reflection angle of the measurement light (irradiation angle of the measurement light) at high speed and at a small pitch while achieving downsizing. Has been done. In addition, the MEMS mirror 15 is, in other words, a single mirror that can rotate about one axis. In addition, a biaxial MEMS mirror is also conceivable. In this case, the cylindrical lens 14 can be omitted. That is, one of the two axes may perform laser scanning, and the other axis may spread the laser (have the same function as the cylindrical lens 14).

  The modularization member 10b has a light transmitting portion so that the measurement light reflected by the MEMS mirror 15 can be emitted to the outside. The modularization member 10b is fixed to the housing 50 so that the light transmitting portion of the modularization member 10b faces the light projecting window 51a of the housing 50. Therefore, the measurement light reflected by the MEMS mirror 15 passes through the light transmitting portion of the modularization member 10b and the light projecting window 51a of the housing 50 and is applied to the measurement object W.

  The scanning unit can be configured by a galvanometer mirror, a mirror that rotates by a stepping motor, or the like in addition to the MEMS mirror 15, and may be any device that can scan the measurement light.

(Structure of the measurement light receiving section 40)
As shown in FIG. 3, the measurement light receiving section 40 receives the measurement light reflected from the measurement object W, outputs the received light amount distribution for displacement measurement, and also emits the illumination light reflected from the measurement object W (illumination). The image sensor can be configured by a two-dimensional array of light receiving elements that receives (light emitted from the unit 30) and outputs a received light amount distribution for image generation. In this embodiment, the condensing optical system 41 is provided, and the measurement light and the illumination light reach the light receiving element of the measurement light receiving section 40 through the condensing optical system 41. The light receiving element of the measurement light receiving section 40 is not particularly limited, but a CCD (charge-coupled device) image sensor or a CMOS image sensor (for converting the intensity of light obtained through the condensing optical system 41 into an electric signal) complementary metal oxide semiconductor) and the like. The condensing optical system 41 is an optical system for condensing light incident from the outside, and typically has one or more optical lenses. The optical axis of the condensing optical system 41 and the optical axis of the light projecting portion 10a intersect each other.

(Configuration of illumination unit 30)
As shown in FIG. 5 and the like, the illuminating section 30 has a plurality of light emitting diodes arranged in the first direction or the second direction so as to be separated from each other, and emits light from different directions with respect to the measuring object W. Irradiation is possible. The illumination unit 30 is turned on when acquiring the luminance image of the measurement object W, and is turned off when the strip-shaped measurement light is output. The illumination unit 30 has a first light emitting diode 31, a second light emitting diode 32, a third light emitting diode 33, and a fourth light emitting diode 34, and a plate-shaped mounting member 30a to which these light emitting diodes 31 to 34 are mounted. There is. The mounting member 30a is arranged along the end wall portion 51 of the housing 50 so as to face the light receiving window 51b. A through hole 30b is formed in the central portion of the mounting member 30a so as to vertically penetrate the mounting member 30a. The incident side of the condensing optical system 41 is arranged so as to coincide with the through hole 30b, and the measurement light and the illumination light reflected by the measuring object W pass through the through hole 30b of the mounting member 30a and the condensing optical system. It is designed to enter 41.

  The 1st-4th light emitting diodes 31-34 are arrange | positioned so that the through-hole 30b of the attachment member 30a may be surrounded, and it has the attitude | position which irradiates light below. Therefore, the light irradiation directions of the first to fourth light emitting diodes 31 to 34 and the optical axis of the measurement light intersect each other.

  The first light emitting diode 31 and the second light emitting diode 32 are separated from each other in the first direction, and the first light emitting diode 31 and the third light emitting diode 33 are separated from each other in the second direction. The second light emitting diode 32 and the fourth light emitting diode 34 are separated from each other in the second direction, and the third light emitting diode 33 and the fourth light emitting diode 34 are separated from each other in the first direction. This makes it possible to irradiate the measuring object W with illumination light from four directions around the optical axis of the condensing optical system 41.

  In this embodiment, the illuminating unit 30 is provided on the sensor head 2 and is integrated with the measurement light receiving unit 40. However, the present invention is not limited to this, and the illuminating unit 30 may be separated from the sensor head 2. Further, the number of light emitting diodes is not limited to four, and can be any number.

(Configuration of angle detection sensor 22)
As shown in FIG. 5, the angle detection sensor 22 is a sensor for detecting the scanning angle of the measurement light by the MEMS mirror 15 when the measurement light is applied to a region including the measurement position of the measurement object W. The angle detection sensor 22 is provided at a position where the light at the end in the first direction of the strip-shaped measurement light scanned by the scanning mirror 15c of the MEMS mirror 15 can be received.

(Electrical configuration of sensor head 2 and amplifier)
As shown in FIG. 6, the sensor head 2 includes an amplifier communication unit 20 and a trigger detection unit 21. The amplifier communication unit 20 is a communication circuit that communicates with the slave unit amplifier 3 and the master unit amplifier 4, and sends and receives signals between the sensor head 2 and the slave unit amplifier 3 and the master unit amplifier 4. The trigger detection unit 21 detects a trigger signal output from the slave unit amplifier 3 or the master unit amplifier 4. When the trigger detection unit 21 detects the trigger signal, the trigger detection unit 21 outputs various signals necessary for measuring the displacement to each unit of the sensor head 2. In this embodiment, as the configuration of the sensor head 2, a configuration for detecting the trigger signal output from the slave unit amplifier 3 or the master unit amplifier 4 is adopted. For example, in the line mode described later, the sensor head 2 may automatically generate the trigger signal. In this case, the sensor head 2 may have a trigger signal generator that generates a trigger signal.

  The laser control unit 12a executes output / stop control of laser light from the laser 12 and output light amount control. The mirror control unit 15a executes the operation of the MEMS mirror 15, that is, the angle adjustment and change of the scanning mirror 15c. The imaging controller 40a executes light reception control (for example, control of exposure time, light reception gain, etc.) by the measurement light receiver 40. The illumination control unit 35 executes lighting / extinguishing control and brightness adjustment of the first to fourth light emitting diodes 31 to 34.

  The angle detection sensor 22 has a one-dimensional light receiving element 22a having a plurality of pixels arranged in the second direction, and an angle detection unit 22b that performs arithmetic processing. Although the angle detection unit 22b is provided in the angle detection sensor 22 in FIG. 6, it may be provided in the FPGA that controls the head. When the light at the end portion in the first direction of the measurement light is incident on the light receiving element 22a, any one of the plurality of pixels arranged in the second direction and the pixel in the vicinity of the pixel are exposed to the light. There will be a clear difference in the amount of light received between pixels. If the pixel having the highest amount of received light and the emission angle of the measurement light from the scanning mirror 15c are obtained in advance from the plurality of pixels arranged in the second direction, the angle detector 22b outputs the light from the light receiving element 22a. The emission angle of the measurement light from the scanning mirror 15c can be detected based on the received light amount distribution. The emission angle of the measurement light from the scanning mirror 15c may be referred to as the irradiation angle of the scanning mirror 15c. Therefore, the angle detector 22b can also detect the irradiation angle of the scanning mirror 15c. The light receiving element 22a may be a one-dimensional CMOS image sensor or a one-dimensional optical position sensor (PSD: Position Sensitive Detector).

  Further, the configuration of the angle detection sensor 22 is not limited to the above-described configuration, a light source for irradiating the reference light for angle detection is provided separately from the light source for the measurement light, and the reference light is directed toward the scanning mirror 15c, The configuration may be such that reflected light from the scanning mirror 15c is incident on an optical position sensor or the like and angle information is obtained based on the output thereof. Further, an angle detection sensor may be built in the MEMS mirror 15. In this case, there are, for example, a counter electromotive force type sensor and a piezo signal type sensor. In this embodiment, the MEMS mirror 15 is adopted as the scanning unit. When a galvanometer mirror is used as the scanning unit, a sensor that detects (real-time) angle feedback from the galvanometer mirror can be used as the angle detection sensor 22.

(Configuration of setting information storage unit 23)
As shown in FIG. 6, the sensor head 2 has a setting information storage unit 23 including various memories. The setting information storage unit 23 can store various setting information transmitted from the slave unit amplifier 3 and the master unit amplifier 4. The specific content stored in the setting information storage unit 23 will be described later. The setting information storage unit 23 may be mounted on the slave unit amplifier 3 or the master unit amplifier 4, or may be mounted on both the sensor head 2 and the slave unit amplifier 3.

(Line mode and scan mode)
FIG. 7A shows an example of the measuring object W. FIG. 7B is a diagram illustrating the line mode. In the line mode, the measuring object W is conveyed at a constant conveying speed in the arrow direction. The sensor head 2 irradiates the strip-shaped measuring light 60 at a predetermined sampling interval and receives the reflected light to obtain height information on the plurality of linear beam spots 61. A collection of height information at each beam spot 61 may be called a profile. That is, the profile is an aggregate of height information of the formation positions of the linear beam spots 61 that are generated by irradiating the measuring object 60 with the strip-shaped measuring light 60 so as to cut the measuring object W. The plurality of profiles acquired at different positions in the second direction serve as information indicating the three-dimensional shape of the measuring object W.

  8A and 8B are diagrams for explaining the scan mode. In the scan mode, the measuring object W is stationary. The sensor head 2 changes the irradiation angle of the measurement light to change the position where the linear beam spot 61 is formed in the second direction. Thereby, a plurality of profiles of the measuring object W are acquired.

(Explanation of measurement principle)
Here, the principle of measuring the displacement of the measuring object W at a predetermined position based on each information obtained by the sensor head 2 will be described. As shown in FIGS. 9A and 9B, the principle of triangulation is basically used. FIG. 9A shows the method adopted in this embodiment, and FIG. 9B shows the modified method, but any method may be adopted. In the line mode, the angle of the MEMS mirror 15 is substantially fixed (may be slightly displaced as described later). In the scan mode, the angle of the MEMS mirror 15 is variable. That is, the MEMS mirror 15 scans the measurement light emitted from the light projecting unit 10a in the second direction, so that the measurement light is emitted to the measurement object W. Reference numeral W1 indicates a relatively high surface of the measuring object W, and reference numeral W2 indicates a relatively low surface of the measuring object W. Hereinafter, the measurement principle of FIG. 9A and the measurement principle (modification) of FIG. 9B will be described in detail.

  In FIG. 9A, the height of the measuring object W is Z, and the projection axis angle is θ2. The projection axis angle θ2 can be detected by the angle detection sensor 22. According to the principle of triangulation, Z can be uniquely specified if the position y (Y coordinate) in the second direction (Y direction) in the measurement light receiving unit 40 and the projection axis angle θ2 are obtained. .. Therefore, it is possible to measure each value of y, θ2, and Z in various patterns through experiments, and store a data set including (y, θ2, Z) as a table in the displacement measuring device 1 in advance. it can. When the displacement measuring device 1 is operated, Z can be obtained from the detected y and θ2 by referring to the table. Also, values not in the table can be obtained by interpolation processing. Further, even if a table is not stored in advance in the displacement measuring device 1, an approximate expression for obtaining Z from (y, θ2) is prepared, and the approximate expression is used when the displacement measuring device 1 is in operation. Alternatively, Z may be calculated.

  Here, in FIG. 9A, the height Z is determined based on the measurement position (Y coordinate) in the second direction (Y direction) and the projection axis angle θ2, but the present invention is not limited to this. The height Z may be determined based on the measurement position (X coordinate and Y coordinate) in the first direction (the depth direction of the paper in FIG. 9A) and the second direction and the projection axis angle θ2. Originally, it is desirable that the measurement light (laser) that extends straight in the first direction and the direction in which the light receiving elements 22a of the measurement light receiving section 40 are arranged (the depth direction in the plane of FIG. 9A) are completely parallel. However, these may become non-parallel due to assembly misalignment during manufacturing. Further, the laser itself may have a curved shape along the first direction due to optical variations. In such a case, if the measurement position is determined only by the Y coordinate in the second direction, correct displacement measurement becomes difficult. Therefore, the height Z may be calculated after taking the measurement position (X coordinate) in the first direction (X direction) into consideration. That is, each value of x, y, θ2, and Z is measured in various patterns by an experiment, and a data set including (x, y, θ2, Z) is stored in the displacement measuring device 1 as a table in advance. Keep it. Then, at the time of operation, the height Z may be obtained based on the three parameters (x, y, θ2). This allows more accurate displacement measurement. Note that, as described above, Z may be calculated not only by the method of storing the table but also by using an approximate expression during operation.

  Next, a modified example will be described with reference to FIG. 9B. In FIG. 9B, the height of the measuring object W is Z, the distance between light emitting and receiving is A (see the arrow in FIG. 9B), the light receiving axis angle is θ1, and the light emitting axis angle is θ2. The light receiving axis angle θ1 can be detected by the light receiving position of the measurement light in the measurement light receiving section 40, and the light projecting axis angle θ2 can be detected by the angle detection sensor 22. A is known and is stored in the displacement measuring device 1. Z can be calculated using A, θ1 and θ2 by a specific well-known calculation formula. An example will be given of a specific calculation formula. First, consider a two-dimensional coordinate plane in which the right direction in FIG. 9B is the + X direction and the upward direction in FIG. 9B is the + Y direction, and the origin of the coordinate plane is the position of the rotation axis of the MEMS mirror 15. Then, the straight line of the projection axis indicated by the angle θ2 in FIG. 9 is represented by a linear equation of y = tan θ2 (inclination of straight line) × x. Further, the straight line of the light receiving axis indicated by the angle θ1 in FIG. 9B is represented by a linear equation of y = tan θ1 (slope of straight line) × x + Atan θ1 (intercept). Since Z corresponds to the y-coordinates of the intersections of these two straight lines, if the simultaneous linear equations are solved to obtain the y-coordinates, they are represented by-{Atan θ1tan θ2 / (tan θ2-tan θ1)}. That is, the distance from the position of the rotation axis of the MEMS mirror 15 to the symbol W2 is the absolute value of this y coordinate. Since the distance from the position of the rotation axis of the MEMS mirror 15 to the housing 50 is known, Z can be obtained by subtracting that distance. It should be noted that such a calculation formula may be used, or each value of Z, θ1, and θ2 may be measured in various patterns by experiments and stored in the displacement measuring device 1 as a table. During operation, Z can be obtained from the detected θ1 and θ2 by referring to the table. Values not in the table can be obtained by interpolation processing. The calculation may be performed each time without using the table. The light receiving axis angle θ1 shown in FIG. 9B has a one-to-one correspondence with the peak position in the second direction of the received light amount distribution.

(Amplifier configuration)
FIG. 10 shows the configuration of the slave unit amplifier 3 (or the configuration of the master unit amplifier 4). In the following description, it is assumed that the slave unit amplifier 3 executes each function, but the slave unit amplifier 3 may include all of these functions, or the master unit amplifier 4 may include some or all of these functions. May be. Further, the sensor head 2 may include some or all of the functions of the slave unit amplifier 3. Further, the monitor device 5A or the personal computer 5B may include some or all of the functions of the slave unit amplifier 3.

  The slave unit amplifier 3 includes a sensor head communication unit 300, a trigger control unit 301, and a storage unit 320. The sensor head communication unit 300 is a part that communicates with the sensor head 2, and sends and receives a signal between the slave unit amplifier 3 and the sensor head 2. The trigger controller 301 is a part that sends a trigger signal to the sensor head 2. When a measurement start trigger signal that defines the measurement start timing is input from the external device 6 via the connection line 6a, the trigger control unit 301 is configured to generate and send a trigger signal. The trigger signal may be a periodic trigger signal.

(Structure of Luminance Image Generation Unit 302)
The luminance image generation unit 302 obtains the amount of received light for image generation output from the measurement light receiving unit 40 when the measurement light receiving unit 40 of the sensor head 2 receives the illumination light reflected from the measurement target W, It is configured to generate a brightness image of the measurement object based on the received light amount distribution for image generation. The generated brightness image is an image that becomes darker as the brightness value output from the measurement light-receiving unit 40 becomes lower and becomes whiter as the brightness value becomes higher, and may be a monochrome image or a color image. . Note that any method may be adopted as the method of generating the luminance image. For example, the received light amount distribution for luminance measurement may be directly used as a luminance image, or as preprocessing in the sensor head 2, FPN (Fixed Pattern Noise) correction, HDR (High-dynamic-range) correction, or the like may be performed. Various kinds of processing may be performed, or as preprocessing in the slave unit amplifier 3, a synthesis processing for executing halation removal may be performed.

  The luminance image generated by the luminance image generation unit 302 is displayed on the display unit 8 while being incorporated in the user interface. The user interface is generated by the UI generation unit 303.

  The display unit 8 is configured to display the luminance image such that the X coordinate on the luminance image becomes the coordinate in the first direction and the Y coordinate on the luminance image becomes the coordinate in the second direction. The X direction on the luminance image displayed on the display unit 8 is the horizontal direction, and the Y direction is the vertical direction.

(Configuration of setting unit 304)
The setting unit 304 is a unit that receives the setting of the measurement position for measuring the displacement on the luminance image displayed on the display unit 8. When the user performs a touch operation on the luminance image displayed on the display unit 8 when there is a portion of the measurement object W where the displacement is to be measured, the setting unit 304 changes the touched position. For example, it is specified by the XY coordinates, and the specified position is set as the measurement position. That is, the measurement position is specified by detecting that the input operation of the measurement position is performed. Thereby, the setting of the measurement position by the user can be accepted.

(Configuration of Edge Extraction Unit 306)
The edge extraction unit 306 is a portion configured to extract the edge of the measurement object W in the luminance image. The edge can be broadly defined as the contour and outline of the measuring object W. The edge extraction processing itself can use a conventionally known method. For example, the pixel value of each pixel on the luminance image is acquired, and the change in the pixel value on the luminance image becomes equal to or more than the threshold for edge detection. When a region exists, the boundary portion is extracted as an edge. The threshold value for edge extraction can be adjusted arbitrarily by the user.

  Specifically, the contour of the object W to be measured, and the part estimated to be the outline are extracted as edges. The edge of the measuring object W is displayed by an edge display line. The edge display line can be configured by, for example, a thick line, a broken line, a line of a conspicuous color such as red or yellow, but the edge display line is not limited to these, and may be in the form of blinking display.

(Configuration of Correction Information Storage Unit 320a)
The correction information storage unit 320a stores information set by the setting unit 304 for correcting the position of the measuring object W. Examples of information that can be used as a reference for position correction include a part of the brightness image generated by the brightness image generation unit 302, brightness information of the brightness image, edge information regarding the edges extracted by the edge extraction unit 306, and the like. it can. When the position correction information is a part of the brightness image, the image can also be called a template image.

  The part of the brightness image can be an image showing a part of the measurement object W in the brightness image generated by the brightness image generation unit 302, and the position and orientation of the measurement object W can be specified. Images in various ranges and positions are preferable. Further, the brightness information of the brightness image can be a brightness value of each pixel, and in this case as well, a pixel value in a range or position that can specify the position and orientation of the measurement object W is preferable. Furthermore, the edge information regarding the edges extracted by the edge extraction unit 306 can be the shape of the edge line, the length, the number of edge lines, the relative position coordinates of a plurality of edge lines, and the like, and in this case also, the measurement target. Edge information that can specify the position and orientation of the object W is preferable.

  The timing for storing the position correction information may be the time when the edge extraction is completed, or the time when the setting of one program is completed, as described later. The correction information storage unit 320a may store the template image and the edge information in association with each other, or may store the edge information without storing the template image.

(Structure of Position Corrector 307)
The position correction unit 307 corrects the position stored in the correction information storage unit 320a on the luminance image newly generated by the luminance image generation unit 302 while the displacement measuring device 1 is operating in the scan mode and the line mode. It is configured to specify the position and orientation of the measuring object W using the usage information and to correct the measurement position using the relative position information.

  For example, when the template image is stored as the position correction information, it is detected whether or not the template image is included in the newly generated luminance image by the normalized correlation, and the template image is included. If is detected, the newly generated luminance image is moved so as to have the position and orientation of the template image at the time of setting, and is rotated to correct the position and orientation of the luminance image. .. At this time, the measurement position on the luminance image newly generated based on the relative position information between the template image and the measurement position is simultaneously corrected.

  When the edge information is stored as the position correction information, it is detected whether or not the corresponding edge is included in the newly generated luminance image, and it is detected that the corresponding edge is included. In this case, the position and orientation of the luminance image are corrected by moving and rotating the newly generated luminance image so that the position and orientation of the luminance image at the time of setting are obtained. At this time, the measurement position on the luminance image newly generated based on the relative position information between the edge information and the measurement position is simultaneously corrected.

  Therefore, even if the position or orientation of the measurement target W changes at the actual measurement site of the measurement target W, it becomes possible to perform the measurement after correcting the position or orientation of the measurement target W to constant positions and orientations. There are several types of position and orientation correction methods. As described above, the position and orientation of the brightness image may be corrected by moving or rotating the brightness image, or the area (tool frame) for the measurement tool may be moved or rotated. Then, the position may be corrected. Further, when the displacement measuring device 1 is operating in the line mode, as described above, the edge extraction is performed on the height profile, and the position is detected based on the relative position information between the extracted edge information and the measurement position. You may make it correct.

(Configuration of measurement tool selection unit 308)
The measurement tool selection unit 308 is a unit that enables selection of one or a plurality of measurement tools. The measurement tool is, for example, a step tool for measuring the size of the step of the measurement object W, a height tool for measuring the height of a predetermined position of the measurement object W, a height area tool described later, or the position of the measurement object W. There is a position correction tool for correcting the above, a MAX / MIN tool for obtaining the minimum and maximum heights of the measurement object W within a predetermined range, and the like, but a measurement tool other than these may be provided.

(Configuration of measurement control unit 305)
The measurement control unit 305 is configured to control the light projecting unit 10a and the MEMS mirror 15 so that the measurement light is irradiated to the measurement position set by the setting unit 304 and the displacement measurement range set by the setting unit 304. At this time, the light projecting unit 10a and the MEMS mirror 15 may be controlled so that the measurement light is emitted only to the region received by the setting unit 304. Further, the measurement control unit 305 can be configured to change the scanning range of the measurement light by the MEMS mirror 15 based on the Y coordinate on the luminance image of the measurement position. Based on the coordinates (and / or the X coordinate) and the displacement measurement range in which the displacement measurement is performed, the scanning range of the MEMS mirror 15 is set narrower than the scannable range in which the MEMS mirror 15 can scan.

(Structure of mode selection unit 309)
The mode selection unit 309 is a portion that enables selection of a mode when the displacement measuring apparatus 1 is in operation, and a line mode in which the measurement object W is irradiated with the measurement light without performing scanning by the MEMS mirror 15, and a measurement light. The user can select an arbitrary mode among the scan modes in which the scanning is performed by the MEMS mirror 15 to irradiate the measuring object W. When the displacement can be measured in the line mode, the measurement can be completed at high speed because the measurement light is not scanned. On the other hand, when measuring a wide range, the scan mode can be used. The line mode / scan mode selection means, for example, generates a mode selection user interface (not shown) by the UI generation unit 303 and displays it on the display unit 8, and receives the user's selection by an operation on the user interface. It can be configured.

  When the scan mode is selected by the mode selection unit 309, the measurement control unit 305 causes the light projecting unit 10a to sequentially emit the measurement light to different positions in the Y direction (second direction) of the measurement target W. And control the MEMS mirror 15. On the other hand, when the line mode is selected by the mode selection unit 309, the measurement control unit 305 causes the light projecting unit 10a and the MEMS to irradiate the measurement light to the same position in the second direction of the measurement target W. It is configured to control the mirror 15. Thereby, the mode switching is executed.

  When the line mode is selected by the mode selection unit 309, the measurement control unit 305 irradiates the measurement light to the same position in the second direction of the measurement target W without operating the scanning mirror 15c. It is configured. Further, the measurement control unit 305 is configured to operate the scanning mirror 15c and irradiate the measurement light to a plurality of positions that are close to each other in the second direction when the line mode is selected by the mode selection unit 309. Has been done.

  Which of the scan mode and the line mode is selected is stored in the setting information storage section 320f of the storage section 320.

(Structure of emission direction adjusting unit 310)
The emission direction adjustment unit 310 is a unit for adjusting the emission direction of the measurement light in the second direction when the line mode is selected by the mode selection unit 309. The emission direction can be adjusted by the user on the user interface, for example.

(Structure of irradiation angle identification unit 311)
The irradiation angle specifying unit 311 continuously acquires the amount of light received at the pixel position of the light receiving element corresponding to the measurement position output from the measurement light receiving unit 40, and the scanning mirror 15c when the measurement light is irradiated to the measurement position. Is a part for specifying the irradiation angle of. The scanning angle of the measurement light by the MEMS mirror 15 when the measurement light is irradiated on the region including the measurement position of the measurement object W can be acquired by the angle detection sensor 22 described above. The irradiation angle of the scanning mirror 15c when the measurement light is irradiated to the measurement position can be calculated based on the output value. The obtained irradiation angle of the scanning mirror 15c is specified as the irradiation angle of the scanning mirror 15c when the measurement light is irradiated to the measurement position. The specified irradiation angle of the scanning mirror 15c is stored in the storage unit 320. In specifying the irradiation angle of the measurement light, the rough irradiation angle can be specified based on the drive signal to the MEMS mirror 15 without using the angle detection sensor 22. However, in consideration of changes in temperature characteristics, changes over time, and the like, it is preferable to measure the angle by the angle detection sensor 22 or the like in order to know the accurate irradiation angle.

(Structure of displacement measuring unit 312)
The measurement principle used by the displacement measuring unit 312 is the above-described triangulation principle. The displacement measuring unit 312 outputs the displacement output from the measuring light receiving unit 40 when the measuring light irradiated to the measuring position set by the setting unit 304 is reflected from the measuring position and received by the measuring light receiving unit 40. The displacement of the measurement position is measured based on the distribution of received light amount for measurement. The measurement result can be stored in the measurement data storage unit 320e.

  The display unit 8 is configured to display the displacement of the measurement position measured by the displacement measuring unit 312 in a relative positional relationship with the maximum displacement measuring range measurable by the displacement measuring unit 312. When the position correction is performed, the measurement light emitted to the measurement position corrected by the position correction unit 307 is reflected from the measurement position and received by the measurement light receiving unit 40. The displacement measuring unit 312 can measure the displacement of the measurement position based on the received light amount distribution for displacement measurement output from the measuring light receiving unit 40 even when the position correction is performed.

  Further, the displacement measuring unit 312 obtains the received light amount distribution for displacement measurement output from the measuring light receiving unit 40 by using the principle of triangulation, and also when the measuring position is irradiated with the measuring light. In addition, the displacement of the measurement position can be measured based on the angle of the scanning mirror 15c (second irradiation angle) detected by the angle detection unit 22b and the position of the measurement position in the Y direction (second direction). .. Further, as described above, the displacement of the measurement position may be measured not only at the position in the Y direction (second direction) but also at the position in the X direction (first direction). Specifically, this can be dealt with by storing calibration data at the time of manufacturing and shipping. For example, the calibration plate is placed at an arbitrary height Z in a state where the measurement light is irradiated, a brightness image is captured, and the direction in which the measurement light extends at that time is recognized. If the light receiving element 22a is not parallel to the longitudinal direction or is curved, the deviation is stored as calibration data. Further, the calibration plate is arranged and changed to a plurality of heights different from the arbitrary height Z, a brightness image is captured each time, and the direction in which the measurement light extends at that time is recognized. As a result, the calibration data at each height Z can be acquired and stored. During operation, based on the position (X coordinate) of the measurement position in the X direction (first direction), the above-described calibration data may be used to accurately measure the displacement of the measurement position.

  The displacement measuring unit 312 measures the displacement of the measurement position based on the irradiation angle specified by the irradiation angle specifying unit 311 and the peak position of the received light amount distribution when the measurement light is irradiated to the measurement position. You can also In this embodiment, the peak position is the position where the received light amount distribution is maximum, but there are various methods for specifying the “peak position”. For example, if there are a plurality of peaks in the received light amount distribution, even if an interpolation curve (a quadratic curve, a cubic curve, etc.) is obtained so as to pass through those peaks, and the position at which the interpolation curve becomes maximum may be obtained. Good. Alternatively, for example, when there are a plurality of peaks in the received light amount distribution, the maximum peak may be estimated from those peaks to obtain the peak position.

  The first height data and the second height data are master data and form three-dimensional data stored together with the luminance image. By storing the first height data and the second height data, for example, when trying to measure with a measurement tool at the time of setting, the first height data or the second height data can be obtained without irradiating the measurement position with the measurement light. The displacement can be obtained from the data and displayed immediately. Further, when the position of the measuring tool is finely adjusted after the setting, the displacement of the changed measuring position can be obtained without preparing the master measurement object W again.

  The height data may be one, but by storing the first height data and the second height data in which the pitch of the measuring light is different, it is possible to measure each measuring tool and each measuring tool size. , It is possible to read and display the displacement from the corresponding height data (for MAX / MIN tools and height area tools, the pitch may be changed by setting an average size of large or small). For example, it is conceivable to hold one master data measured at a fine pitch and use it by thinning it out, but the master data created by thinning may not completely match the final processing, so the pitches of multiple measurement lights It is preferable to hold height data different from each other. The height data is stored in the height data storage unit 320b of the storage unit 320.

  In addition, the displacement measuring unit 312 acquires the received light amount distribution for displacement measurement output from the measuring light receiving unit 40 each time the measuring light is emitted when the line mode is selected by the mode selecting unit 309. The displacement of the measuring object is measured a plurality of times. The displacement measuring unit 312 can also be configured to average the obtained plurality of displacements. The term "averaging" in this specification is not limited to an average in a narrow sense, but is a broad concept including, for example, trim average and median.

(Structure of the quality determination unit 313)
The quality determination unit 313 determines the state of the measurement target W based on the brightness image generated by the brightness image generation unit 302, and the state of the measurement target W based on the displacement measured by the displacement measurement unit 312. It is configured to determine whether the measuring object W is good or bad by combining with the determination result of determining. For example, it is detected whether or not a part is missing on the luminance image, and even if it is not missing, if the displacement measured by the displacement measuring unit 312 is outside the reference value, the measurement target It can be determined that the item W is defective. On the contrary, if the displacement measured by the displacement measuring unit 312 is the reference value and it is determined that a part is missing on the luminance image, the measurement target W is determined to be a defective product. be able to. The processing result can be stored in the processing result storage unit 320c shown in FIG.

(Configuration of setting information storage unit 320f)
The setting information storage unit 320f stores a program. The program is made up of a plurality of setting information and can be stored in a plurality of ways. As the setting information included in each program, for example, which of a scan mode and a line mode is selected, trigger-related settings, imaging-related settings (brightness, sensitivity, etc.), the presence or absence of master data, head tilt correction, It includes applicable measurement tools and their parameters. The user can select an arbitrary program from the programs stored in the setting information storage section 320f and apply it when the displacement measuring apparatus 1 is in operation.

(Specific example during setting and operation)
Next, a specific example of the displacement measuring device 1 during setting and operation will be described. FIG. 11 is a flowchart showing a procedure performed when setting the scan mode of the displacement measuring device 1.

(When setting scan mode)
Step SA1 in the flowchart at the time of setting the scan mode is a step of setting an external trigger, an internal trigger and the like, and sets what kind of trigger signal and how to operate. When the trigger condition is set, the setting information is sent to the slave unit amplifier 3 and the sensor head 2, and the sensor head 2 operates under this condition.

  In step SA2, the brightness of the brightness image is set. The brightness setting refers to the exposure time, the amount of illumination light, the imaging mode (whether or not there is HDR), and the like. HDR is a high dynamic range process. Brightness can be set automatically or manually.

  In step SA3, master registration is performed. The master is a brightness image and three-dimensional data (height data) of the entire field of view. The sensor head 2 acquires a brightness image of the measurement object W and scans the measurement object W with measurement light. Then, the displacement is measured and the height data is acquired. The brightness image and the height data are associated and stored in the height image storage unit 320b. In step SA3, a plurality of height data can be acquired by scanning the measuring light with different pitches. Various methods are conceivable for acquiring a plurality of height data. For example, the measurement light is scanned at a predetermined finest pitch to obtain one height data, and for pitches coarser than this pitch (pitch having a high resolution), the one height data is thinned out. It may be generated. Furthermore, master registration may be omitted.

  In step SA4, the measurement tool selection interface is displayed on the display unit 8 to select the measurement tool. When the measurement tool is selected, the process proceeds to step SA5 and each tool is set. Although there is no set order for the measurement tools, the position correction tool is the first in the processing order. Only one position correction tool may be set for all the other measurement tools, or it may be set individually for each of the other measurement tools.

  In step SA6, it is determined whether the addition of the measurement tool is completed. If the addition of the measurement tool is not completed, the measurement tool is added through steps SA4 and SA5. When the addition of the measurement tool is completed, the process proceeds to step SA7. In step SA7, output allocation is set. Then, in step SA8, the comprehensive judgment condition is set.

(During scan mode operation)
FIG. 12 is a flowchart showing a procedure performed when the displacement measuring apparatus 1 is operating in the scan mode. In step SG1 in the flowchart during operation in the scan mode, an external trigger is accepted from the external device 6 or the like. In step SG2, the first to fourth light emitting diodes 31 to 34 of the lighting unit 30 are turned on. In step SG3, a brightness image is captured. The image data is stored in, for example, the image data storage unit 320d of the slave unit amplifier 3.

  In step SG4, it is determined whether or not the position correction tool is applied. If the position correction tool is selected at the time of setting, the process proceeds to step SG5, and if the position correction tool is not selected at the time of setting, the process proceeds to step SG7. The position correction tool is executed in step SG5, and the position of the measurement tool, that is, the measurement position is corrected in step SG6. Steps SG5 and SG6 are performed by the position correction unit 307.

  In step SG7, it is determined whether or not the image processing tool is applied. If the image processing tool is selected at the time of setting, the process proceeds to step SG8, and if the image processing tool is not selected at the time of setting, the process proceeds to step SG9. In step SG8, various image processes are executed. As the image processing, conventionally known ones can be mentioned.

  In step SG9, it is determined whether or not the real-time tilt correction is applied. If execution of the tilt correction function is selected at the time of setting, the process proceeds to step SG10, and if execution of the tilt correction function is not selected at the time of setting, the process proceeds to step SG18. In step SG10, the MEMS mirror 15 is controlled so that the displacement in the displacement measurement range including the measurement position can be measured. In step SG11, the laser light is emitted from the laser 12 to irradiate the measuring object W with the strip-shaped measuring light. The image is taken in step SG12, and the displacement is measured in step SG13.

  In step SG14, it is determined whether or not all of the first to third points have been measured. When all the measurements of the first to third points are not completed, the above-described processing is repeated until the measurement of the three points is completed. When the measurement of all the first to third points is completed, the process proceeds to step SG15, and the reference plane is calculated from the first to third points. Then, it progresses to step SG16 and the irradiation pitch of the measurement light in the displacement measurement range is optimized according to the reference plane direction. In step SG17, the scanning range of the measurement light is optimized according to the height of the reference surface.

  In step SG18, it is determined whether or not the measurement tool is applied. If the measurement tool is selected at the time of setting, the process proceeds to step SG19, and if the measurement tool is not selected at the time of setting, the process proceeds to step SG24. In step SG19, the MEMS mirror 15 is controlled so that the displacement in the displacement measurement range including the measurement position can be measured according to the measurement tool. In step SG20, the measuring object W is irradiated with the strip-shaped measuring light emitted from the laser 12. An image is taken in step SG21, and the displacement is measured in step SG22. When all the measurements are completed in step SG23, the process proceeds to step SG24, and when all the measurements are not completed, the above measurement is repeated. In step SG24, the processing results of all the measurement tools are integrated to generate a comprehensive determination result. The generated comprehensive determination result is output.

(When line mode is set)
FIG. 13 is a flowchart when the line mode is set. Steps for setting external triggers, internal triggers, etc. are omitted. In step SP1, the brightness of the brightness image is set. In step SP2, master registration is performed. In step SP3, the measurement tool is selected. When the measurement tool is selected, the process proceeds to step SP4 and each tool is set. In step SP5, it is determined whether the addition of the measurement tool is completed. If the addition of the measurement tool is not completed, the measurement tool is added through steps SP3 and SP4. When the addition of the measurement tool is completed, the process proceeds to step SP6. In step SP6, output allocation is set. Then, in step SP7, the comprehensive judgment condition is set.

  A virtual measurement bright line is superimposed and displayed on the luminance image displayed on the user interface. The measurement bright line shows a portion irradiated with the measurement light and is displayed so as to correspond to the irradiation position of the measurement light.

(During line mode operation)
FIG. 14 is a flowchart showing a procedure performed when the displacement measuring apparatus 1 is operating in the line mode. In step SR1 in the flow chart during operation in the line mode, the trigger signal is periodically output. In step SR2, the first to fourth light emitting diodes 31 to 34 of the lighting unit 30 are turned on. In step SR3, a brightness image is captured. In step SR4, the MEMS mirror 15 is controlled so that the displacement in the displacement measurement range including the measurement position can be measured. In step SR5, the laser light is emitted from the laser 12 to irradiate the measuring object W with the strip-shaped measuring light. An image is taken in step SR6, and the displacement is measured in step SR7.

  In step SR8, it is determined whether or not the position correction tool is applied. If the position correction tool is selected at the time of setting, the process proceeds to step SR9, and if the position correction tool is not selected at the time of setting, the process proceeds to step SR11. The position correction tool is executed in step SR9, and the position of the measurement tool, that is, the measurement position is corrected in step SR10.

  In step SR11, it is determined whether or not the measurement tool is applied. If the measurement tool is selected at the time of setting, the process proceeds to step SR12, and if the measurement tool is not selected at the time of setting, the process proceeds to step SR13. In step SR12, the measurement tool is executed. When all the measurements are completed, the processing results of all the measurement tools are integrated in step SR13 to generate a comprehensive determination result. The generated comprehensive determination result is output.

(Countermeasures against vibration of the scanning mirror)
As described above, the MEMS mirror 15 has the scanning mirror 15c driven by the driving unit 15b. When unintended vibration occurs in the scanning mirror 15c, the angle of the scanning mirror 15c is not stable, and it becomes difficult to irradiate the measurement light 60 to the target position. The drive unit 15b includes a drive coil, and a magnetic field (magnetic force) is generated by passing a current through the drive coil, and the magnet 15d acts on this magnetic field to control the angle of the scanning mirror 15c to a desired angle. When unintended vibration occurs in the scanning mirror 15c, an induced electromotive force (hereinafter simply referred to as an electromotive force) is generated in the coil. Therefore, if a current is passed through the coil so as to cancel this electromotive force, the vibration of the scanning mirror 15c is reduced.

  FIG. 15 shows the mirror control unit 15a and the MEMS mirror 15. The angle command unit 70 is a part that commands the angle of the scanning mirror 15c. For example, the angle command unit 70 outputs a voltage corresponding to the target angle. The adder 71a adds the voltage from the angle command unit 70 and the voltage from the amplifier circuit 74 and outputs the result to the drive circuit 72. The drive circuit 72 converts the voltage output from the adder 71 a into a current and applies the current to the MEMS mirror 15. The electromotive force detection circuit 73 detects an electromotive force generated in the MEMS mirror 15 due to unintended vibration and outputs the detection result to the amplification circuit 74. The amplifier circuit 74 amplifies the detection result and outputs it to the adder 71a. In this way, since the detection result of the electromotive force is fed back to the angle command, unintended vibration is suppressed.

  FIG. 16 is a circuit diagram showing a specific example of the mirror controller 15a. The digital-analog conversion circuit DAC is an example of the angle command unit 70, and converts the angle command given as a digital value from the measurement control unit 305 or the like into an analog value Vin and outputs the analog value Vin. The VI conversion circuit IC1 is an example of the drive circuit 72, converts the input voltage into the drive current I, and supplies the drive current I to the drive coil L1 of the drive unit 15b. The MEMS mirror 15 has a scanning mirror 15c, a drive coil L1, and a magnet 15d. The scanning mirror 15c and the drive coil L1 are integrated, and the magnet 15d is arranged apart from the scanning mirror 15c. When a current flows through the drive coil L1, a magnetic field is generated and acts on the magnet 15d, and the angle of the scanning mirror 15c is controlled to the target angle. A magnet 15d may be attached to the scanning mirror 15c, and the drive coil L1 may be arranged outside the scanning mirror 15c. The electromotive force detection circuit 73 includes a detection resistor Rs, a variable gain amplifier IC2, and an adder 71b. The amplifier circuit 74 is composed of an amplifier IC3. When the drive current I flows through the drive coil L1, the drive current I also flows through the detection resistor Rs. Therefore, the voltage Vb can be expressed using the resistance value Rs of the detection resistor Rs.

Vb = Rs × I (1)
Further, the MEMS mirror 15 is represented by an equivalent circuit in which the resistance (MEMS resistance Rm) of the MEMS mirror 15, the drive coil L1, and the electromotive force e are connected in series. Therefore, the voltage Va is expressed by the following equation.

Va = Rm × I + e + Rs × I (2)
The voltage Vbb is the voltage Vb amplified by the gain G.

Vbb = Vb × G
= Rs × I × G (3)
The potential difference Vdiff is expressed by the following formula.

Vdiff = Va-Vbb
= (Rm * I + e + Rs * I) -Rs * I * G
= (Rm x I + e) -Rs x I x (G-1) (4)
Here, the gain G for making Vdiff = electromotive force e is expressed by the following equation.

G = 1 + (Rm / Rs) (5)
Since Rm and Rs are known here, G is also known. That is, by setting the gain G so as to satisfy the expression (5), the electromotive force e is fed back to the drive current I through the amplifier IC3. This reduces unintentional vibration.

(Temperature characteristics of MEMS resistance Rm)
Depending on the configuration of the MEMS mirror 15, the MEMS resistance Rm changes depending on the temperature. Since the MEMS mirror 15 is a very small component, the drive coil L1 may be made of a very thin line. Further, in order to generate a sufficient magnetic force, the length of the line forming the drive coil L1 may be considerably long. This means that the MEMS resistance Rm has a very large resistance value. When the resistance value of the MEMS resistor Rm becomes large, the voltage of the MEMS resistor Rm becomes much larger than the electromotive force e, and it becomes difficult to detect the electromotive force e. In the circuit diagram shown in FIG. 16, the electromotive force e can be detected by measuring the MEMS resistance Rm in advance and amplifying the electromotive force e according to the MEMS resistance Rm.

  Since the MEMS mirror 15 is a very small component, the drive coil L1 is packaged in the MEMS mirror 15 and is subject to heat dissipation limitation. When the temperature of the MEMS mirror 15 rises, the MEMS resistance Rm changes. However, as the expression (5) shows, if the gain G can be adjusted according to the MEMS resistance Rm, unintended vibration can be reduced. For that purpose, a circuit for measuring the MEMS resistance Rm is required.

  By modifying the equation (4), an equation for obtaining the MEMS resistance Rm can be obtained.

Rm = {Vdiff−e + Rs × I × (G−1)} (6)
Here, the electromotive force e is zero when no unintended vibration is generated. In this case, equation (6) can be transformed into equation (7).

Rm = {Vdiff + Rs × I × (G-1)} (7)
Here, the drive current I and the gain G are known because they are set values. Since the detection resistance Rs has a fixed value, it is known. Therefore, if Vdiff can be measured, the MEMS resistance Rm can be obtained.

  FIG. 17 is a diagram showing the mirror control unit 15a provided with a measure against the temperature characteristic of the MEMS resistor Rm. The resistance detection circuit 75 is a circuit that detects the MEMS resistance Rm based on Vdiff. The gain setting circuit 76 is a circuit that sets the gain G based on the MEMS resistance Rm.

  FIG. 18 is a circuit diagram of the mirror controller 15a. The amplifier IC4 amplifies Vfb which is the output of the amplifier IC3 which amplifies Vdiff, and generates the voltage Ver. The analog-digital conversion circuit ADC is a circuit that converts the analog voltage Ver into a digital value. The voltage Ver is a voltage proportional to Vdiff, and is a voltage substantially correlated with the MEMS resistance Rm. Therefore, it may be understood that the amplifier IC4 and the analog-digital conversion circuit ADC form the resistance detection circuit 75. The CPU 79 calculates the gain G using the equations (7) and (5) and sets the gain G in the variable gain amplifier IC2. The CPU 79 may function as an arithmetic circuit that calculates the MEMS resistance Rm from the voltage Ver (that is, Vdiff). That is, the analog-digital conversion circuit ADC and the CPU 79 may function as the resistance detection circuit 75. Further, the CPU 79 functions as the gain setting circuit 76 in order to calculate the gain G based on the MEMS resistance Rm and set the gain G in the variable gain amplifier IC2.

  By adjusting the gain G based on the MEMS resistance Rm in this way, it becomes possible to accurately reduce vibration even if the temperature of the drive coil L1 rises.

  Equation (7) is based on the premise that the scanning mirror 15c is not vibrating, that is, the electromotive force e is 0. This means that the MEMS resistance Rm is measured while the scanning mirror 15c is sufficiently stable at the target angle. However, the present invention is not limited to this. For example, the electromotive force e in the equation (6) can be regarded as almost zero by time averaging. That is, the CPU 79 may calculate the MEMS resistance Rm by time-averaging Vdiff.

  When the gain G satisfies the expression (5) in the initial state, Vdiff becomes zero. Therefore, thereafter, the CPU 79 may adjust the gain G so that Vdiff becomes zero. As a result, even if the MEMS resistance Rm changes, the vibration can be accurately reduced.

(Other measures against vibration)
FIG. 19 is a diagram showing the mirror controller 15a. In this example, the detection coil L2 for detecting the electromotive force e generated in the drive coil L1 is provided in the MEMS mirror 15 as the electromotive force detection circuit 73.

  FIG. 20 is a circuit diagram showing the mirror controller 15a. An electromotive force e ′ proportional to the electromotive force e generated in the drive coil L1 is generated in the detection coil L2. A current I ′ proportional to this electromotive force e ′ flows through the detection resistor Rs. As a result, the voltage Vb is generated at one end of the detection resistor Rs. The amplifier IC5 amplifies the voltage Vb to generate the voltage Vfb. As a result, the voltage Vfb is fed back to the drive current I so as to reduce the vibration.

(Summary)
The illumination unit 30 is an example of a light source that outputs light. The collimator lens 13, the cylindrical lens 14, and the diaphragm member 16 function as a conversion optical system that converts the light output from the light source into planar measurement light and outputs it. The MEMS mirror 15 functions as a light guide optical system that guides the planar measurement light emitted from the conversion optical system toward the surface of the measurement target W. The measurement light receiving unit 40 functions as a light receiving unit that receives the reflected light from the measurement target W. Based on the principle of triangulation, the displacement measuring unit 312 acquires a profile, which is an aggregate of the heights of the respective reflection positions of the planar measurement light on the measurement target W, according to the incident position of the reflected light on the light receiving unit. Functions as a profile acquisition unit. The light guide optical system may have the following components. The scanning mirror 15c is a mirror that deflects the planar measurement light, and functions as a mirror that can change the reflection direction of the planar measurement light. The drive unit 15b and the drive coil L1 function as a drive unit that changes the reflection direction of the mirror by driving the mirror. The electromotive force detection circuit 73 or the like functions as a detection unit that detects vibration from the outside with respect to the mirror or vibration that occurs in the mirror until the angle of the mirror stabilizes at the target angle when the angle of the mirror is changed. The mirror control unit 15a functions as a control unit that controls the drive unit so that the vibration of the mirror converges based on the detection result of the detection unit. As a result, unintended vibration is reduced, so that the profile of the surface of the measuring object W can be obtained more accurately.

  The drive coil L1 is an example of a first coil to which a current corresponding to a target angle is supplied from a drive unit (eg, drive circuit 72). The magnet 15d functions as a magnet that generates a magnetic force that acts on the first coil. The electromotive force detection circuit 73 functions as a detection circuit that detects electromotive force generated at both ends of the first coil. The mirror control unit 15a may feed back the detection result of the electromotive force detected by the detection circuit to the current supplied to the first coil so that the vibration of the mirror is suppressed.

  The electromotive force detection circuit 73 may have a detection resistor Rs connected in series with the first coil to detect the electromotive force. The amplifier circuit 74, the variable gain amplifier IC2, and the amplifier IC3 are examples of an amplifier that amplifies the electromotive force detected by the detection resistor. The electromotive force amplified by these amplifiers may be fed back to the current supplied to the first coil.

  As shown in FIGS. 17 and 18, the gain G of the amplifier may be adjusted according to the resistance value of the first coil (eg, MEMS resistance Rm). Even if the resistance value of the first coil changes due to temperature, it is possible to accurately reduce vibration.

  As shown in FIGS. 19 and 20, the drive coil L1 is an example of a first coil to which a current corresponding to the target angle is supplied from the drive unit. The magnet 15d is an example of a magnet that generates a magnetic force that acts on the first coil. The detection coil L2 is a second coil that constitutes a part of the detection unit, and functions as a second coil that is arranged to vibrate in conjunction with the first coil. The electromotive force detection circuit 73, the detection resistor Rs, and the like function as a detection circuit that detects the voltage generated across the second coil. The mirror control unit 15a may feed back the detection result of the detection circuit to the current supplied to the first coil so that the vibration of the mirror is suppressed. This makes it possible to reduce vibration with high accuracy.

DESCRIPTION OF SYMBOLS 1 ... Displacement measuring device, 2 ... Sensor head, 10 ... Projector, 40 ... Photodetector, 50 ... Housing, 305 ... Measurement controller, 312 ... Displacement measuring unit

Claims (6)

A light source that outputs light,
A conversion optical system that converts the light output from the light source into a planar measurement light and outputs the converted light.
A light guide optical system that guides the planar measurement light emitted from the conversion optical system so as to be directed toward the surface of a measurement target,
A light receiving unit for receiving the reflected light from the measurement object,
Based on the principle of triangulation, profile acquisition for acquiring a profile that is an aggregate of heights of respective reflection positions of the planar measurement light in the measurement object according to the incident position of the reflected light in the light receiving unit Part and
The light guide optical system,
A mirror for deflecting the planar measurement light, the mirror being capable of changing the reflection direction of the planar measurement light,
A drive unit that changes the reflection direction of the mirror by driving the mirror,
Vibration from the outside with respect to the mirror, or a detection unit that detects vibration generated in the mirror until the angle of the mirror stabilizes at a target angle when the angle of the mirror is changed,
A profile measuring device comprising: a control unit that controls the drive unit so that vibration of the mirror converges based on a detection result of the detection unit. A first coil supplied with current from the drive unit according to the target angle;
And a magnet that generates a magnetic force that acts on the first coil,
The detection unit has a detection circuit that detects an electromotive force generated at both ends of the first coil,
The control unit feeds back the detection result of the electromotive force detected by the detection circuit to the current supplied to the first coil so that the vibration of the mirror is suppressed. The profile measuring device described in 1.   The profile measuring device according to claim 2, wherein the detection circuit has a detection resistor connected in series with the first coil to detect the electromotive force. Further comprising an amplifier for amplifying the electromotive force detected by the detection resistor,
The profile measuring device according to claim 3, wherein the electromotive force amplified by the amplifier is fed back to the current supplied to the first coil.   The profile measuring apparatus according to claim 4, wherein the gain of the amplifier is adjusted according to the resistance value of the first coil. A first coil supplied with current from the drive unit according to the target angle;
A magnet that generates a magnetic force that acts on the first coil;
A second coil forming a part of the detection unit, further comprising a second coil arranged to vibrate in conjunction with the first coil,
The detection unit has a detection circuit for detecting a voltage generated across the second coil,
The profile measuring device according to claim 1, wherein the control unit feeds back a detection result of the detection circuit to the current supplied to the first coil so that vibration of the mirror is suppressed. .