JP2007101215A - Shape measurement method, shape measurement system and shape measurement device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shape measurement method, shape measurement system and shape measurement device capable of measuring the shape of a measurement object while inhibiting the degradation of the measurement precision. <P>SOLUTION: In the case, the XY stage 14 is driven with a constant speed, while previously performing a sampling mode, information of the temporal variation of the max. light receiving amount on the light receiving surface 19a is obtained. When the measurement mode is performed, the distances of the work W is measured at each moving position of irradiation spot Q while changing the moving speed of the XY stage 14 based on the variation of the max. light receiving amount. At each moving position of the irradiation spot Q where the variation of the light receiving amount is large at the time of performing the sampling mode, the lowering of the precision of measurement caused by the tracking delay of the feed back control is inhibited by lowering the moving speed of the XY stage 14. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a shape measuring method, a shape measuring system, and a shape measuring apparatus.

  For example, in Patent Document 1 below, a measurement object is irradiated with light from a light source, the reflected light is received by an image sensor, and the measurement object is received from the light source and the image sensor based on the light reception position of the reflected light in the image sensor. An optical displacement meter for measuring the distance to is disclosed. In such an optical displacement meter, when the light projecting unit is always driven with a constant light projection amount, the amount of light received by the image sensor changes due to unevenness or color difference on the surface of the measurement object, and the light reception position in the image sensor is accurately determined. It may not be detected well and may interfere with distance measurement. Therefore, some conventional optical displacement meters control the amount of light emitted from the light projecting unit so that the amount of light received by the image sensor is fed back to obtain a constant amount of received light.

And such an optical displacement meter moves the measurement object relative to the direction intersecting the irradiation direction of the light from the light source, so that the light receiving position at the image sensor corresponding to each moving position. It is also used for shape measurement for measuring the surface shape of the measurement object based on the above.
JP 2001-50711 A

  By the way, when used for the shape measurement, the amount of light received by the image sensor fluctuates due to the uneven shape or color change of the surface of the measurement object during the movement of the light irradiation spot by the movement mechanism. Of course, in the above configuration, if the received light amount change is relatively gradual by feedback control, it is corrected following. However, when the change in the amount of received light fluctuates relatively large, the moving mechanism is driven at a constant speed while the follow-up delay of the feedback control occurs, and the light receiving position at the image sensor corresponding to each irradiation spot. Cannot be detected accurately, and as a result, there is a problem that accuracy of shape measurement is lowered.

  The present invention has been completed based on the above circumstances, and its purpose is to provide a shape measuring method, a shape measuring system, and a shape measuring method capable of measuring the shape of a measurement object while suppressing a decrease in measurement accuracy. A shape measuring device is provided.

As a means for achieving the above object, the shape measuring method according to the invention of claim 1 irradiates the measurement object with light from the light projecting unit, and reflects the reflected light according to the distance to the measurement object. The position detection unit detects light at a position on the light-receiving surface that changes, and moves the irradiation spot of light from the light projecting unit on the measurement object within the measurement range, while moving the position at each moving position. In the shape measurement method for measuring the shape of the measurement object based on the light receiving position on the light receiving surface sequentially detected by the detection unit, the irradiation on the measurement object while keeping the light projection amount of the light projection unit constant A first step of sampling a change in the amount of light received by the position detection unit when the spot is moved within the measurement range, and the amount of light received at the light receiving surface is fed back to make the amount of received light constant. While measuring the amount of light emitted from the light section, the irradiation spot is measured while changing the movement speed of the irradiation spot with respect to the movement speed in the first step based on the change in the amount of received light sampled in the first step. And a second step of measuring the shape by moving within a range.
The “change in the amount of received light at the position detector” of the present invention includes a change in the maximum amount of received light at the portion showing the maximum amount of received light on the light receiving surface, a change in the total amount of received light received by the entire light receiving surface, Among them, the change in the total received light amount within a range showing the received light amount above a certain level is included.
“Move the irradiation spot” means that the irradiation spot is moved by relatively moving the light projecting unit and the position detecting unit and the measurement object. Specifically, the irradiation spot is moved by moving the light projecting unit and the position detecting unit side with respect to the measurement target, and the measurement target is moved with respect to the light projecting unit and the position detecting unit side. And moving the irradiation spot.
The “reflected light received by the position detection unit” is a concept that may be regular reflection light of the light from the light projecting unit on the measurement object or diffuse reflection light.

  In the shape measuring method according to the second aspect of the present invention, the measurement object is irradiated with light from the light projecting unit, and the reflected light can be detected at a position on the light receiving surface that varies depending on the distance to the measurement object. A light receiving surface that is detected by a position detection unit, moves an irradiation spot of light from the light projecting unit on the measurement object within a measurement range, and is sequentially detected by the position detection unit at each moving position. In the shape measuring method for measuring the shape of the measurement object based on the light receiving position, the irradiation spot on the measurement object is moved within the measurement range while keeping the light projection amount of the light projecting unit constant. The first step of sampling the received light amount change at the position detecting unit, and adjusting the projected light amount of the light projecting unit in the increasing / decreasing direction to cancel the received light amount change based on the received light amount change sampled in the first step The irradiation spot is moved within the measurement range, characterized in that it comprises a second step of performing the shape measurement with.

  A shape measurement system according to a third aspect of the present invention includes a light projecting unit that irradiates light to a measurement object, and a light receiving surface that receives reflected light from the measurement object, and the reflected light on the light receiving surface A position detection unit that outputs a position signal based on a light receiving position at the light source, a moving mechanism that moves an irradiation spot of light from the light projecting unit on the measurement object within a measurement range, and the irradiation by the moving mechanism In the process of moving the spot, a measurement unit that repeatedly captures a position signal from the position detection unit to measure the shape of the measurement object, and is sampled prior to the measurement operation by the measurement unit, and the light projection amount of the light projection unit A memory for storing received light amount change information in the position detection unit when the irradiation mechanism on the measurement object is moved within the measurement range by driving the moving mechanism while maintaining a constant; At the time of the measurement operation by the measurement unit, a light projection amount feedback control unit that performs a light projection amount control of the light projection unit to feed back a light reception amount on the light receiving surface of the position detection unit and make the light reception amount constant, A speed control unit configured to control a moving speed of the moving mechanism based on received light amount change information stored in the memory during the measurement operation by the measuring unit;

In addition, the following structure may be sufficient.
(Structure A) The speed control unit is characterized in that the moving speed of the moving mechanism is reduced at a moving position of an irradiation spot where there is a change in received light amount that is a predetermined value or more based on the received light amount change information. The shape measuring system according to claim 3.
(Configuration B) The measurement unit uses a position signal obtained from the position detection unit at a moving position of an irradiation spot having a change in received light amount of a predetermined value or more based on the received light amount change information, for measuring the shape of the measurement object. The shape measuring system according to Configuration A, wherein the shape measuring system is not.

  A shape measuring system according to a fourth aspect of the present invention includes a light projecting unit that irradiates light to a measurement object, and a light receiving surface that receives reflected light from the measurement object, and the reflected light on the light receiving surface A position detection unit that outputs a position signal based on a light receiving position at the light source, a moving mechanism that moves an irradiation spot of light from the light projecting unit on the measurement object within a measurement range, and the irradiation by the moving mechanism In the process of moving the spot, a measurement unit that repeatedly captures a position signal from the position detection unit to measure the shape of the measurement object, and is sampled prior to the measurement operation by the measurement unit, and the light projection amount of the light projection unit A memory for storing received light amount change information in the position detection unit when the irradiation mechanism on the measurement object is moved within the measurement range by driving the moving mechanism while maintaining a constant; A light projection amount forward control unit that forward-controls the light projection amount of the light projecting unit in an increase / decrease direction that cancels the light reception amount change based on the light reception amount change information stored in the memory during the measurement operation by the measurement unit; It is characterized by providing.

  The shape measurement system according to the invention of claim 5 includes a light projecting unit that irradiates light to the measurement object, and a light receiving surface that receives reflected light from the measurement object, and the reflected light on the light receiving surface A position detection unit that outputs a position signal based on a light receiving position at the light source, a moving mechanism that moves an irradiation spot of light from the light projecting unit on the measurement object within a measurement range, and the irradiation by the moving mechanism In the process of moving the spot, a measurement unit that repeatedly captures a position signal from the position detection unit and measures the shape of the measurement object, and irradiates the irradiation spot with a certain amount of light at a position in the front of the moving direction. And a photoelectric sensor for detecting the amount of received reflected light and the projection for feeding back the amount of received light on the light receiving surface of the position detecting unit during the measurement operation by the measuring unit. A projection light amount feedback control unit for controlling the projection light amount of the unit, and a moving speed by the moving mechanism is controlled based on a change in received light amount detected in advance by the photoelectric sensor during the measurement operation by the measurement unit. And a speed control unit.

  The shape measuring system according to the invention of claim 6 has a light projecting unit for irradiating light to the measuring object and a light receiving surface for receiving the reflected light from the measuring object, and the reflected light on the light receiving surface A position detection unit that outputs a position signal based on a light receiving position at the light source, a moving mechanism that moves an irradiation spot of light from the light projecting unit on the measurement object within a measurement range, and the irradiation by the moving mechanism In the process of moving the spot, a measurement unit that repeatedly captures a position signal from the position detection unit and measures the shape of the measurement object, and irradiates the irradiation spot with a certain amount of light at a position in the front of the moving direction. A photoelectric sensor for detecting the amount of received reflected light, and a method of increasing / decreasing the amount of received light based on a change in the amount of received light detected in advance by the photoelectric sensor during the measurement operation by the measurement unit Characterized in that and a projection amount forward control unit for forward control the projection amount of the projecting portion.

  The shape measuring apparatus according to the invention of claim 7 has a light projecting unit that irradiates light to a measurement object that is relatively moved by a moving mechanism, and a light receiving surface that receives reflected light from the measurement object, A position detection unit that outputs a position signal based on a light receiving position of the reflected light on the light receiving surface, and a process in which an irradiation spot of light from the light projecting unit is moved within a measurement range by the moving mechanism, A measurement unit that repeatedly captures a position signal from a position detection unit and measures the shape of the measurement object, and is sampled prior to the measurement operation by the measurement unit, and the movement while keeping the light projection amount of the light projection unit constant A memory storing received light amount change information in the position detection unit when the irradiation spot on the measurement object is moved within the measurement range by a mechanism, and during the measurement operation by the measurement unit At the time of the measurement operation by the measurement unit, a light projection amount feedback control unit that performs a light projection amount control of the light projection unit to feed back a light reception amount on the light receiving surface of the position detection unit and make the light reception amount constant And a control signal output unit that outputs a control signal for controlling the moving speed of the moving mechanism to the moving mechanism based on the received light amount change information stored in the memory.

  The shape measuring apparatus according to the invention of claim 8 has a light projecting unit that irradiates light to a measurement object that is relatively moved by a moving mechanism, and a light receiving surface that receives reflected light from the measurement object, A position detection unit that outputs a position signal based on a light receiving position of the reflected light on the light receiving surface, and a process in which an irradiation spot of light from the light projecting unit is moved within a measurement range by the moving mechanism, A measurement unit that repeatedly captures a position signal from a position detection unit and measures the shape of the measurement object, and is sampled prior to the measurement operation by the measurement unit, and the movement while keeping the light projection amount of the light projection unit constant A memory storing received light amount change information in the position detection unit when the irradiation spot on the measurement object is moved within the measurement range by a mechanism, and during the measurement operation by the measurement unit Characterized in that and a projection amount forward control unit for forward control the projection amount of the projecting portion in the decrease direction to offset the amount of received light changes on the basis of the received light amount change information stored in the memory.

  The shape measuring apparatus according to the invention of claim 9 includes a light projecting unit that irradiates light to a measurement object that is relatively moved by a moving mechanism, and a light receiving surface that receives reflected light from the measurement object, A position detection unit that outputs a position signal based on a light receiving position of the reflected light on the light receiving surface, and a process in which an irradiation spot of light from the light projecting unit is moved within a measurement range by the moving mechanism, A measurement unit that repeatedly captures a position signal from a position detection unit and measures the shape of the measurement object, and a received amount of reflected light by irradiating the irradiation spot with a certain amount of light at a position before the movement direction And a light projection amount control of the light projecting unit for feeding back the amount of received light on the light receiving surface of the position detecting unit and making the received light amount constant during the measurement operation by the measuring unit. The amount of light to be emitted During the measurement operation by the back control unit and the measurement unit, a control signal for controlling the movement speed by the movement mechanism based on a change in the amount of received light detected in advance by the photoelectric sensor is sent to the movement mechanism. And a control signal output unit for outputting.

  The shape measuring apparatus according to the invention of claim 10 includes a light projecting unit that irradiates light to a measurement object that is relatively moved by a moving mechanism, and a light receiving surface that receives reflected light from the measurement object, A position detection unit that outputs a position signal based on a light receiving position on the light receiving surface of the reflected light, and a process in which an irradiation spot of light from the light projecting unit is moved within the measurement range by the moving mechanism, A measurement unit that repeatedly captures a position signal from the position detection unit and measures the shape of the measurement object; and receives a reflected light by irradiating the irradiation spot with a predetermined amount of light at a position before the moving direction. A photoelectric sensor for detecting the amount of light, and during the measurement operation by the measurement unit, the light projecting unit in an increasing / decreasing direction that cancels the change in the amount of received light based on a change in the amount of received light detected in advance by the photoelectric sensor The amount of light emitted Characterized in that it comprises a projection amount forward control unit for de control, the.

<Invention of claims 1, 3 and 7>
According to this configuration, the shape of the measurement object is measured while moving the irradiation spot at a speed based on the received light amount change characteristic sampled before detecting the light receiving position at each moving position based on the light irradiation from the light projecting unit. I do. For example, when the change in the amount of received light is large, feedback control is required correspondingly, and the movement speed of the irradiation spot is reduced correspondingly. Thereby, it is possible to perform shape measurement while suppressing a follow-up delay in feedback control. When sampling the change in the amount of received light, the irradiation spot on the measurement object may be moved while changing its moving speed, but the structure of moving at a constant speed is more desirable.

<Invention of Claims 2, 4 and 8>
According to this configuration, the light projecting unit is increased or decreased in the increase / decrease direction to cancel the light reception amount change based on the received light amount change characteristic sampled prior to detection of the light reception position at each moving position based on the light irradiation from the light projecting unit. The amount of emitted light was adjusted. Therefore, it is possible to suppress a decrease in shape measurement accuracy due to a feedback control follow-up delay that may have occurred in the conventional configuration.

<Invention of Claims 5 and 9>
According to this configuration, the moving speed of the moving mechanism is controlled based on a pre-change in the reflected light amount from the photoelectric sensor that detects the reflected light amount before the moving direction with respect to the irradiation spot of the light from the light projecting unit; did. Thereby, it is possible to perform shape measurement while suppressing a follow-up delay in feedback control.

<Invention of claims 6 and 10>
According to this configuration, the amount of light emitted from the light projecting unit is controlled based on a pre-change in the amount of reflected light from the photoelectric sensor that detects the amount of reflected light before the light spot emitted from the light projecting unit. It was. Thereby, the light projection amount control is performed with a margin compared to the conventional configuration in which feedback control is performed based on the reflected light amount at the light irradiation spot from the light projecting unit itself, and the reduction of the shape measurement system can be suppressed.

<Embodiment 1>
A first embodiment of the present invention will be described with reference to FIGS.
1. Overall Configuration of Shape Measurement System FIG. 1 is an overall schematic diagram of a shape measurement system 10 of this embodiment. This shape measuring system 10 includes an XY on which a shape measuring device 13 to which a sensor head portion 11 and a controller portion 12 are connected via a signal cable, and a workpiece W (corresponding to the “measurement object” of the present invention) are placed. A stage 14 (corresponding to the “movement mechanism” of the present invention) is provided.

(1) Shape Measuring Device The sensor head unit 11 includes a laser diode (LD) 15 as a light projecting element, an LD drive circuit 16 for driving the laser diode 15, and a laser beam L1 emitted from the laser diode 15. Is provided on the surface of the workpiece W. The laser diode 15, the LD drive circuit 16, and the light projecting lens 17 correspond to the “light projecting unit” of the present invention.

  Further, the sensor head unit 11 includes a light receiving lens 18, a CCD linear sensor 19 as a position detecting element that receives the laser light L 2 transmitted through the light receiving lens 18, and a CCD drive circuit for driving the CCD linear sensor 19. 20. The light receiving lens 18, the CCD linear sensor 19, and the CCD drive circuit 20 correspond to the “position detection unit” of the present invention.

  The laser light L1 emitted from the laser diode 15 passes through the light projecting lens 17 and is irradiated onto the workpiece W. Then, the diffusely reflected light L 2 on the workpiece W passes through the light receiving lens 18 and enters the CCD linear sensor 19. The charge accumulated in the CCD linear sensor 19 according to the received light amount and the relative position of the work is read out by the CCD drive circuit 20 and converted into a time-series voltage signal.

  When the CCD drive circuit 20 gives a predetermined transfer clock to the CCD linear sensor 19, the CCD linear sensor 19 sequentially transfers the charges accumulated in each pixel one pixel at a time. Then, the CCD drive circuit 20 outputs a time-series voltage signal S1 (corresponding to the “position signal” of the present invention) corresponding to the accumulated charges of all the pixels.

  The controller unit 12 includes a CPU 21, a memory 22, and operation keys 23. In the “measurement mode” and “sampling mode” described later, the CPU 21 gives a drive signal S2 to the LD drive circuit 16 to cause the laser diode 15 to perform a light projection operation, and is set by, for example, an input operation with the operation key 23. The CCD driving circuit 20 is driven at the set sampling period T to execute a light receiving operation for transferring the accumulated charge of each pixel of the CCD linear sensor 19, and the voltage signal S1 from the CCD driving circuit 20 is A / D converted. receive.

  With the above configuration, in the sensor head unit 11, the light receiving position P of the diffusely reflected light L2 on the light receiving surface 19a of the CCD linear sensor 19 (corresponding to the “light receiving position on the light receiving surface” in the present invention) is the shape measuring device 13. It moves according to the distance from the (projecting lens 17) to the irradiation spot Q of the workpiece W. The CPU 21 can measure the height displacement of the workpiece W by analyzing the voltage signal S1 and detecting the light receiving position P of the diffuse reflected light L2 on the light receiving surface 19a of the CCD linear sensor 19.

  More specifically, the CPU 21 receives the voltage signal S <b> 1 from the CCD drive circuit 20, detects a pixel having the maximum light reception amount from all the pixels on the light receiving surface 19 a of the CCD linear sensor 19, and stores a measurement data storage area in the memory 22. Store in chronological order. At this time, the CPU 21 functions as a “measurement unit” of the present invention.

(2) XY stage The XY stage 14 is configured to be movable in two directions orthogonal to XY on the horizontal plane on which the workpiece W is placed. The XY stage 14 receives a control signal S3 from the CPU 21 and moves at a direction and speed according to the control signal S3.
Then, the shape measurement system 10 performs a light projecting operation, and performs a light receiving operation at each set sampling period T while moving the XY stage 14 in, for example, the X direction (the direction of the white arrow in FIG. 1). The cross-sectional shape (height displacement) in the X direction of the workpiece W can be measured.

  In the present embodiment, for example, in the process of scanning the irradiation spot Q on the surface of the workpiece W, the number of distance measurements (S8 in FIG. 3 described later) is performed to set the shape measurement of the workpiece W. The number of measurements and the measurement pitch interval for each distance measurement can be set with the operation keys 23. Then, the CPU 21 sets the conditions for the set sampling cycle and the moving speed of the XY stage 14 suitable for the above-mentioned measurement times and measurement pitch intervals.

  Specifically, for example, when the desired number of measurements and the length of the workpiece W are set, the total length of the workpiece W is determined by the desired number of measurements from the currently set moving speed (first speed) of the XY stage 14. The set sampling period T is automatically changed so that distance measurement can be performed. Alternatively, the moving speed (first speed) of the XY stage 14 is automatically changed so that the distance measurement can be performed for the entire length of the workpiece W with a desired number of measurements from the current set sampling period T.

  In addition, it is possible to set with the operation key 23 how many cycles of the maximum received light amount data are to be executed based on the average value of the maximum received light amount data at the time of light emission amount control described later. In this case, the CPU 21 changes the set sampling period according to the set number of periods (for example, shortens the sampling period when the number of periods is large) or changes the moving speed of the XY stage 14 (for example, the number of periods is If there are many, slow down the moving speed, etc.).

2. Sampling Mode and Measurement Mode Now, the light receiving position P of the diffusely reflected light L2 on the light receiving surface 19a of the CCD linear sensor 19, more specifically, the pixels having the maximum light receiving amount from all the pixels on the light receiving surface 19a of the CCD linear sensor 19 Is detected with high accuracy, the received light level of the diffusely reflected light L2 on the light receiving surface 19a must be kept at an appropriate constant target level Th1. The reason is that if the light receiving level at the light receiving surface 19a is low, the difference in the received light amount between the pixel having the maximum light receiving amount and the other pixels becomes small, and it becomes difficult to specify the pixel having the maximum light receiving amount accordingly. On the other hand, even if the amount of light received at the light receiving surface 19a is increased, it cannot be increased to a level at which the CCD linear sensor 19 is saturated.

  Therefore, the CPU 21 executes feedback control (so-called APC (Automatic Power Control) control) so as to keep the received light amount level on the light receiving surface 19a at the target level Th1 at each set sampling period T when the measurement mode is executed. . Specifically, the CPU 21 monitors the received light amount of the pixel having the maximum received light amount based on the voltage signal S1 from the CCD drive circuit 20, and this received light amount (in this embodiment, four cycles before the set sampling timing). A drive signal S2 is applied to the LD drive circuit 16 in order to control the amount of light emitted from the laser diode 15 in an increasing / decreasing direction that cancels out the difference between the maximum received light amount average value) and the target level Th1. At this time, the CPU 21 functions as the “light projection feedback control unit” of the present invention.

  However, some of the workpieces W have, for example, surface gloss and color that are not uniform. When measuring the shape of the workpiece W, for example, in the scanning process of moving the irradiation spot Q by moving the XY stage 14 at a constant speed. The amount of light received at the light receiving surface 19a may change extremely. For example, in the case of a workpiece W having a black portion and a white portion on the surface, the received light amount level at the light receiving surface 19a greatly changes at the boundary between the black portion and the white portion. For this reason, in the configuration in which the XY stage 14 is moved at a constant speed and the light receiving operation is repeatedly performed at the set sampling period T, the CPU 21 cannot catch up with the above-described feedback control, and the light receiving level at the light receiving surface 19a reaches the target level Th1. The light receiving position P on the light receiving surface 19a is detected on the basis of the voltage signal S1 at a low level that does not reach, so that the detection accuracy (sensitivity) is lowered, and as a result, the accuracy of the entire shape measurement may be lowered. .

  Therefore, in the present embodiment, the controller unit 12 can select and set the “sampling mode” and the “measurement mode” by operating the operation keys 23. In the following, the shape measurement when the XY stage 14 is driven in the X direction will be described. However, the shape measurement when the XY stage 14 is driven in the Y direction is the same process, and the description is omitted.

(1) Sampling mode When the user sets the “sampling mode” with the operation key 23 and performs a predetermined confirming operation, the CPU 21 sends a control signal S3 instructing to move at a constant first speed V1, for example, in the X direction. The XY stage 14 is given and driven. At the same time, the CPU 21 repeatedly executes the light receiving operation for each set sampling period T while executing the light projecting operation, and the light receiving amount Dn of the pixel having the maximum light receiving amount at each sampling timing (hereinafter simply referred to as “the maximum light receiving amount Dn”). Is stored in the received light amount data storage area of the memory 22 in time series.

  And this operation | movement is performed over the full length of the X direction of the workpiece | work W. FIG. At this time, the CPU 21 does not execute the above-described feedback control, and samples the maximum received light amount Dn on the light receiving surface 19a when the laser diode 15 is projected at a constant level in time series. Note that the received light amount Dn data of the pixel having the maximum received light amount in time series corresponds to the “received light amount change information” of the present invention.

  The upper part of FIG. 2 is a timing chart showing the movement position of the irradiation spot Q on the workpiece W in the X direction and the transition of the maximum received light amount Dn for each set sampling period T with reference to the length of the workpiece W in the X direction. It is. In addition, the white part of the surface of the workpiece | work W in the same figure shows a white part, and a shaded part shows a black part.

  The CPU 21 reads the time-series maximum received light amount Dn data stored in the received light amount data storage area of the memory 22 and extracts, for example, a sampling timing at which a received light amount change of a predetermined level Th2 or more has occurred between each sampling timing. In the upper part of the figure, the maximum received light amount Dn greatly changes between the movement positions AB of the irradiation spots Q and between the CDs by a predetermined level Th2 or more. The predetermined level Th2 is a change amount of the maximum received light amount (average value) for which the above-described feedback control is executed. In the case of a change amount smaller than the predetermined level Th2, there is substantially no influence on the measurement accuracy and feedback. Control is not performed.

  Then, the CPU 21 moves the irradiation spot Q between the movement positions AB of the irradiation spot Q where the received light amount change is equal to or higher than the predetermined level Th2, and the irradiation spot Q where the received light amount change is higher than the predetermined level Th2. While the irradiation spot Q moves between the movement positions CD, the control signal S3 for temporarily switching the movement speed of the XY stage 14 to the second speed V2 (<V1) slower than the first speed V1 is generated. And stored in the memory 22. The CPU 21 functions as a “speed control unit” and a “control signal output unit” of the present invention in the measurement mode.

(2) Measurement mode After the execution of the sampling mode, when the user sets the “measurement mode” with the operation key 23 and performs a predetermined confirmation operation, the CPU 21 executes the control shown in the flowchart of FIG. The CPU 21 first initializes the sampling counter N (the above-mentioned number of measurements) to “1” in S1, and then the CPU 21 starts the light projection operation in S2, and receives the control signal S3 stored in the memory 22 in S3. While being supplied to the XY stage 14 and being driven, it waits for the sampling timing for each set sampling period T in S4. When the sampling timing arrives (“Y” in S4), the CPU 21 executes a light receiving operation and takes in the voltage signal S1 from the CCD drive circuit 20 (S5).

  In S6, the CPU 21 detects the maximum received light amount Dn by analyzing the voltage signal S1 and stores it in the memory 22 in association with each sampling timing. For example, for a plurality of cycles before the current sampling timing (in this embodiment, An average value K of the maximum received light amounts (Dn-3, Dn-2, Dn-1, Dn) for 4 cycles) is calculated. Next, in S7, the CPU 21 determines whether or not the difference between the average value K and the target level Th1 is less than a predetermined level Th2. If it is less than the predetermined level Th2 (“Y” in S7), the CPU 21 detects the light receiving position P on the light receiving surface 19a by analyzing the voltage signal S1 captured at the current sampling timing, and the XY stage 14 at this time The data is stored in the measurement data storage area of the memory 22 in association with the movement position (S8). Thereafter, the CPU 21 enters a standby state in which S1 is added to the sampling counter N in S9 and the next sampling timing is waited.

  On the other hand, if the CPU 21 determines that the difference between the average value K and the target level Th1 is greater than or equal to the predetermined level Th2 (“N” in S7), the maximum of the four cycles from which the average value K is based in S10 The received light amount (Dn-3, Dn-2, Dn-1, Dn) data is discarded from the memory 22, and the light emission amount adjustment by the feedback control is executed so as to cancel the difference between the average value K and the target level Th1. (S11).

  Next, in S12, the CPU 21 detects the maximum received light amount data by the light receiving operation for a plurality of periods (three periods in the present embodiment), stores it in the memory 22, returns to S4, and waits for the next sampling timing. Become. Then, when the next sampling timing arrives (“Y” in S4), the CPU 21 executes the processing of S5 to S7 (in S6, the maximum light reception amount for the three cycles in S12 and the current maximum light reception). The average value K of the quantity is calculated). At this time, the feedback control is executed so as to cancel the difference between the average value K and the target level Th1 in S11, and the light emission amount adjustment is performed, so in S7, the difference between the average value K and the target level Th1 is a predetermined level. It is determined that it is less than Th2 (“Y” in S7), and the distance measurement in S8 is executed.

3. 2 shows the movement position of the irradiation spot Q on the workpiece W in the X direction and the movement of the XY stage 14 at each set sampling period T with reference to the length of the workpiece W in the X direction. It is a timing chart which showed speed. In addition, the white part of the surface of the workpiece | work W in the same figure shows a white part, and a shaded part shows a black part.

  When the measurement mode described above is executed by the CPU 21, the XY stage 14 is driven at the first speed as shown in the lower part of FIG. While the irradiation spot Q is located in the white portion of the workpiece W, the CPU 21 determines that the difference between the average value K and the target level Th1 is less than the predetermined level Th2 (“Y” in S7). That is, there is almost no change in the amount of received light on the light receiving surface 19a, and the target level Th1 is maintained substantially. Feedback control is not executed, and the light receiving position P can be stably detected at each movement position of the irradiation spot Q. The distance measurement of S8 is executed every set sampling period T.

  Thereafter, when the irradiation spot Q reaches the movement position A on the workpiece W, the movement speed of the XY stage 14 is switched to a second speed that is slower than the first speed. While the irradiation spot Q moves from the movement position A to the movement position B, the irradiation spot Q moves at this second speed. During this time, when the irradiation spot Q moves from the white portion on the workpiece W to the black portion, the CPU 21 determines that the difference between the average value K and the target level Th1 is equal to or greater than the predetermined level Th2 (“N” in S7). ), The light emission amount is adjusted by feedback control. Then, after this light projection amount adjustment, the distance measurement (S8) is executed after newly acquiring the maximum received light amount data for four cycles.

  Here, in the present embodiment, the maximum received light amount data acquired when the received light amount on the light receiving surface 19a changes significantly is discarded, and the light receiving position P is determined based on the maximum received light amount data when stabilized to some extent by the light projection amount control. Detect and measure distance. For this reason, the shape measurement of the workpiece | work W based on distance measurement with high precision is attained. Moreover, the movement speed of the irradiation spot Q is slower between the movement positions A and B where the amount of light received on the light receiving surface 19a can change greatly than when moving in a portion where the amount of light received on the light receiving surface 19a is small. Therefore, even if the above processing is performed, the measurement pitch is not so much affected.

  Note that the maximum received light amount data acquired when the amount of light received at the light receiving surface 19a changes greatly is not discarded, and the light receiving position P based on the maximum received light amount data is also used for measuring the shape of the workpiece W. Compared to the conventional configuration in which the irradiation spot Q is moved, the shape can be measured with high accuracy. However, in the present embodiment, more accurate shape measurement is performed by not using the light reception position P based on the maximum light reception amount data acquired when the light reception amount on the light receiving surface 19a changes greatly.

  Also, when the irradiation spot Q reaches the movement position C on the workpiece W, the movement speed of the XY stage 14 is switched to the second speed slower than the first speed, and the irradiation spot Q moves from the movement position C to the movement position. While moving to D, the irradiation spot Q moves at this second speed.

<Embodiment 2>
The second embodiment (corresponding to the inventions of claims 2, 4, and 8) is partially different from the first embodiment in the control contents in the measurement mode, and the other points are the same as the first embodiment. Therefore, the same reference numerals as those in the first embodiment are given and the redundant description is omitted, and only different points will be described next.

  In the first embodiment, the moving speed of the XY stage 14 is changed based on the time-series maximum received light amount Dn obtained by executing the sampling mode. In contrast, in the present embodiment, the light projection amount of the laser diode 15 is forward-controlled based on the time-series maximum received light amount Dn obtained by executing the sampling mode.

  That is, the CPU 21 moves the XY stage 14 at a constant speed (first speed) in the measurement mode. The CPU 21 does not perform feedback control based on the maximum amount of light received at the light receiving surface 19a at that time between the movement positions AB and CD of the irradiation spot Q where the amount of reflected light of the diffusely reflected light L2 can change greatly. Based on the received light amount change information acquired in the mode, forward control is performed so that the maximum received light amount on the light receiving surface 19a does not decrease. For example, between the moving positions AD, the second level is changed to be higher than the first level at other positions.

  Since the laser diode 15 is changed to an appropriate light projection amount by the forward control, the feedback control in S11 of FIG. 3 is not executed (“Y” in S7). Compared to the case where the light emission amount is adjusted by feedback control, the case where the light amount adjustment is performed by forward control has less follow-up delay, and the maximum light reception amount at the light receiving surface 19a is held at a substantially constant target level Th1. Distance measurement (S8) at each movement position of the irradiation spot Q is executed. Thereby, the shape measurement of the workpiece | work W can be performed accurately.

<Embodiment 3>
FIG. 4 shows a third embodiment (corresponding to the inventions of claims 5, 6, 9 and 10). The shape measurement system 30 of the present embodiment includes a reflective photoelectric sensor 31 in addition to the sensor head unit 11 and the controller unit 12 described in the first embodiment. The photoelectric sensor 31 is arranged in front of the movement direction of the sensor head unit 11 with respect to the workpiece W, and samples the amount of reflected light at a position before the irradiation spot Q by the sensor head unit 11. Specifically, the photoelectric sensor 31 includes a laser diode 32 as a light projecting element, and a light receiving element 33 that receives reflected light emitted from the laser diode 32 and reflected by the surface of the workpiece W. Then, the photoelectric sensor 31 sequentially gives the light reception signal S4 to the CPU 21 at a timing synchronized with the set sampling cycle, for example, according to the amount of light received by the light receiving element 33. The light receiving element of the photoelectric sensor 31 may be a CCD linear sensor that can specify the maximum light receiving pixel, as in the sensor head unit 11 of the first embodiment.

  In the present embodiment, the speed control of the XY stage 14 and the laser are performed based on the received light amount data preliminarily acquired by the photoelectric sensor 31 when the measurement mode is executed without executing the sampling mode described above. The amount of light emitted from the diode 15 is controlled.

  Specifically, in contrast to the first embodiment, the CPU 21 does not use the maximum received light amount data acquired in the sampling mode, but the received light amount change detected at a slightly previous timing by the photoelectric sensor 31 is a predetermined level Th2 or more. If it is determined that there is, the moving speed of the XY stage 14 is temporarily switched from the first speed V1 to the second speed V2 at a timing delayed by that timing.

  For the second embodiment, the CPU 21 determines that the change in the amount of received light detected at a slightly previous timing by the photoelectric sensor 31 is not less than the predetermined level Th2, not the maximum amount of received light data acquired in the sampling mode. If determined, the laser diode 15 is changed from the first level to the second level at a timing delayed by the timing.

  With such a configuration, the speed control of the XY stage 14 can be performed based on the received light amount change information acquired in advance by the photoelectric sensor 31 in the measurement mode without requiring the sampling mode as in the first and second embodiments. The amount of light emitted from the laser diode 15 can be controlled.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention, and further, within the scope not departing from the gist of the invention other than the following. Various modifications can be made.
(1) In each of the above embodiments, the position detection unit is of a linear image sensor type using the CCD linear sensor 19 as a position detection element. However, the position detection unit is not limited to this, and a PSD (Position Sensitive Detector) is used as the position detection element. ) May be of the PSD system.

  (2) In each of the above embodiments, the sensor head unit 11 is a so-called diffuse reflection type that receives diffusely reflected light from the workpiece W. However, the present invention is not limited to this, and for example, the workpiece W has a regular reflection surface. If it is, the so-called specular reflection type that irradiates the workpiece W with the laser light L1 from the laser diode 15 obliquely from above and receives the specular reflection light may be used.

  (3) In the first embodiment, the configuration is such that the XY stage 14 is changed to the uniform second speed V2 regardless of the level of the received light amount at the movement position of the irradiation spot Q where the change in the received light amount changes greatly. However, the speed may be reduced by an amount corresponding to (proportional to) the amount of change in the maximum amount of received light.

  (4) In the second embodiment, the light projection amount of the laser diode 15 is changed to the uniform second level regardless of the received light amount level at the movement position of the irradiation spot Q where the change in the received light amount changes greatly. However, the present invention is not limited to this, and the configuration may be such that the light projection amount is changed by an amount corresponding to (proportional to) the change amount of the maximum light reception amount.

  (5) In the above-described embodiment, the “measurement range” is a range extending over the entire length of the workpiece W in the X direction, but is not limited to this, and may be a partial range of the surface of the workpiece W.

1 is an overall schematic diagram of a shape measurement system according to Embodiment 1 of the present invention. Timing chart showing the transition of the movement position of the irradiation spot Q, the maximum received light amount Dn, etc. for each set sampling period T Flow chart showing control contents in measurement mode Overall schematic diagram of shape measurement system according to Embodiment 3

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,30 ... Shape measuring system 13 ... Shape measuring apparatus 14 ... XY stage (movement mechanism)
15 ... Laser diode (light emitting part)
16 ... LD drive circuit (light emitting part)
17 ... Projection lens (projection unit)
18. Light receiving lens (position detection unit)
19 ... CCD linear sensor (position detector)
19a ... Light receiving surface 20 ... CCD drive circuit (position detection unit)
21 ... CPU (projection feedback control unit, measurement unit, speed control unit, control signal output unit)
22 ... Memory 31 ... Photoelectric sensor P ... Light receiving position (light receiving position on the light receiving surface)
Q ... Irradiation spot S1 ... Voltage signal (position signal)
S3 ... Control signal W ... Workpiece (object to be measured)

Claims (10)

The measurement object is irradiated with light from the light projecting unit, and the reflected light is received by the position detection unit that can be detected at a position on the light receiving surface that changes according to the distance to the measurement object. Measuring the shape of the measurement object based on the light receiving position on the light receiving surface sequentially detected by the position detecting unit at each moving position while moving the irradiation spot of the light from the light projecting unit on the upper side In the shape measurement method for performing
A first step of sampling a change in received light amount at the position detection unit when the irradiation spot on the measurement object is moved within the measurement range while keeping a light projection amount of the light projecting unit constant;
The irradiation spot is moved based on the change in the received light amount sampled in the first step while controlling the light projection amount of the light projecting unit to feed back the received light amount on the light receiving surface to make the received light amount constant. And a second step of measuring the shape by moving the irradiation spot within the measurement range while changing the speed with respect to the moving speed in the first step. The measurement object is irradiated with light from the light projecting unit, and the reflected light is received by the position detection unit that can be detected at a position on the light receiving surface that changes according to the distance to the measurement object. The irradiation spot of the light from the light projecting unit is moved within the measurement range, and the shape of the measurement object is measured based on the light receiving position on the light receiving surface sequentially detected by the position detecting unit at each moving position. In the shape measurement method for performing
A first step of sampling a change in received light amount at the position detection unit when the irradiation spot on the measurement object is moved within the measurement range while keeping a light projection amount of the light projecting unit constant;
The shape measurement is performed by moving the irradiation spot within the measurement range while adjusting the light projection amount of the light projecting unit in the increasing / decreasing direction that cancels the light reception amount change sampled in the first step. And a second step of performing a shape measurement method. A light projecting unit for irradiating the object to be measured;
A position detecting unit that has a light receiving surface that receives reflected light from the measurement object, and that outputs a position signal based on a light receiving position of the reflected light on the light receiving surface;
A moving mechanism for moving an irradiation spot of light from the light projecting unit on the measurement object within a measurement range;
In the process of moving the irradiation spot by the moving mechanism, a measurement unit that repeatedly takes in a position signal from the position detection unit and measures the shape of the measurement object;
Sampled prior to the measurement operation by the measurement unit, and when the irradiation spot on the measurement object is moved within the measurement range by driving the moving mechanism while keeping the light projection amount of the light projection unit constant A memory for storing received light amount change information in the position detection unit,
A light projection amount feedback control unit for performing a light projection amount control of the light projecting unit to feed back a light reception amount on a light receiving surface of the position detection unit and to make the light reception amount constant during the measurement operation by the measurement unit; ,
A shape measuring system comprising: a speed control unit that controls a moving speed of the moving mechanism based on received light amount change information stored in the memory during the measuring operation by the measuring unit. A light projecting unit for irradiating the object to be measured;
A position detecting unit that has a light receiving surface that receives reflected light from the measurement object, and that outputs a position signal based on a light receiving position of the reflected light on the light receiving surface;
A moving mechanism for moving an irradiation spot of light from the light projecting unit on the measurement object within a measurement range;
In the process of moving the irradiation spot by the moving mechanism, a measurement unit that repeatedly takes in a position signal from the position detection unit and measures the shape of the measurement object;
Sampled prior to the measurement operation by the measurement unit, and when the irradiation spot on the measurement object is moved within the measurement range by driving the moving mechanism while keeping the light projection amount of the light projection unit constant A memory for storing received light amount change information in the position detection unit,
At the time of the measurement operation by the measurement unit, a light projection amount forward control unit that forward-controls the light projection amount of the light projection unit in an increase / decrease direction that cancels the light reception amount change based on the light reception amount change information stored in the memory; A shape measuring system comprising: A light projecting unit for irradiating the object to be measured;
A position detecting unit that has a light receiving surface that receives reflected light from the measurement object, and that outputs a position signal based on a light receiving position of the reflected light on the light receiving surface;
A moving mechanism for moving an irradiation spot of light from the light projecting unit on the measurement object within a measurement range;
In the process of moving the irradiation spot by the moving mechanism, a measurement unit that repeatedly takes in a position signal from the position detection unit and measures the shape of the measurement object;
A photoelectric sensor that irradiates the irradiation spot with a certain amount of light at a position before the moving direction and detects the amount of reflected light received;
A light projection amount feedback control unit for performing a light projection amount control of the light projecting unit to feed back a light reception amount on a light receiving surface of the position detection unit and to make the light reception amount constant during the measurement operation by the measurement unit; ,
A shape control comprising: a speed control unit that controls a moving speed of the moving mechanism based on a change in received light amount detected in advance by the photoelectric sensor during the measurement operation by the measuring unit. system. A light projecting unit for irradiating the object to be measured;
A position detecting unit that has a light receiving surface that receives reflected light from the measurement object, and that outputs a position signal based on a light receiving position of the reflected light on the light receiving surface;
A moving mechanism for moving an irradiation spot of light from the light projecting unit on the measurement object within a measurement range;
In the process of moving the irradiation spot by the moving mechanism, a measurement unit that repeatedly takes in a position signal from the position detection unit and measures the shape of the measurement object;
A photoelectric sensor that irradiates the irradiation spot with a certain amount of light at a position before the moving direction and detects the amount of reflected light received;
Light projection amount for forward control of the light projection amount of the light projecting unit in the increase / decrease direction that cancels the change in the light reception amount based on the change in the light reception amount detected in advance by the photoelectric sensor during the measurement operation by the measurement unit A shape measuring system comprising: a forward control unit; A light projecting unit that irradiates light to a measurement object that is relatively moved by a moving mechanism;
A position detecting unit that has a light receiving surface that receives reflected light from the measurement object, and that outputs a position signal based on a light receiving position of the reflected light on the light receiving surface;
In the process in which the irradiation spot of light from the light projecting unit is moved within the measurement range by the moving mechanism, a measurement unit that repeatedly captures a position signal from the position detection unit and measures the shape of the measurement object;
The position when the irradiation spot is sampled prior to the measurement operation by the measurement unit and the irradiation spot on the measurement object is moved within the measurement range by the moving mechanism while keeping the light projection amount of the light projection unit constant. A memory for storing received light amount change information in the detection unit;
A light projection amount feedback control unit for performing a light projection amount control of the light projecting unit to feed back a light reception amount on a light receiving surface of the position detection unit and to make the light reception amount constant during the measurement operation by the measurement unit; ,
A control signal output unit that outputs a control signal for controlling the moving speed of the moving mechanism to the moving mechanism based on the received light amount change information stored in the memory during the measurement operation by the measuring unit; A shape measuring apparatus characterized by that. A light projecting unit that irradiates light to a measurement object that is relatively moved by a moving mechanism;
A position detecting unit that has a light receiving surface that receives reflected light from the measurement object, and that outputs a position signal based on a light receiving position of the reflected light on the light receiving surface;
In the process in which the irradiation spot of light from the light projecting unit is moved within the measurement range by the moving mechanism, a measurement unit that repeatedly captures a position signal from the position detection unit and measures the shape of the measurement object;
The position when the irradiation spot is sampled prior to the measurement operation by the measurement unit and the irradiation spot on the measurement object is moved within the measurement range by the moving mechanism while keeping the light projection amount of the light projection unit constant. A memory for storing received light amount change information in the detection unit;
At the time of the measurement operation by the measurement unit, a light projection amount forward control unit that forward-controls the light projection amount of the light projection unit in an increase / decrease direction that cancels the light reception amount change based on the light reception amount change information stored in the memory; A shape measuring apparatus comprising: A light projecting unit that irradiates light to a measurement object that is relatively moved by a moving mechanism;
A position detecting unit that has a light receiving surface that receives reflected light from the measurement object, and that outputs a position signal based on a light receiving position of the reflected light on the light receiving surface;
In the process in which the irradiation spot of light from the light projecting unit is moved within the measurement range by the moving mechanism, a measurement unit that repeatedly captures a position signal from the position detection unit and measures the shape of the measurement object;
A photoelectric sensor that irradiates the irradiation spot with a certain amount of light at a position before the moving direction and detects the amount of reflected light received;
A light projection amount feedback control unit for performing a light projection amount control of the light projecting unit to feed back a light reception amount on a light receiving surface of the position detection unit and to make the light reception amount constant during the measurement operation by the measurement unit; ,
At the time of the measurement operation by the measurement unit, a control signal output for outputting a control signal for controlling the moving speed by the moving mechanism to the moving mechanism based on a change in the amount of received light detected in advance by the photoelectric sensor And a shape measuring device comprising: a portion. A light projecting unit that irradiates light to a measurement object that is relatively moved by a moving mechanism;
A position detecting unit that has a light receiving surface that receives reflected light from the measurement object, and that outputs a position signal based on a light receiving position of the reflected light on the light receiving surface;
A measurement unit that repeatedly captures a position signal from the position detection unit and measures the shape of the measurement object in a process in which an irradiation spot of light from the light projecting unit is moved within a measurement range by the moving mechanism; ,
A photoelectric sensor that irradiates the irradiation spot with a certain amount of light at a position before the moving direction and detects the amount of reflected light received;
Light projection amount for forward control of the light projection amount of the light projecting unit in the increase / decrease direction that cancels the change in the light reception amount based on the change in the light reception amount detected in advance by the photoelectric sensor during the measurement operation by the measurement unit And a forward control unit.

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