displacement sensor

Abstract

A displacement sensor (10) includes an illumination section (11) including an illumination element (11a), a light receiving section (12) including an image sensor (12a), a control section (13), and a storage section (14). The light receiving section (12) outputs an image signal (S12) corresponding to reflected light (L2) from an object (W) received by the image sensor (12a). The control section (13) performs feedback control, i.e., adjusts an operation amount of at least one of an amount of illumination including the illumination element (11a) and an amount of light reception of the image sensor (12a) based on a light receiving level of the image signal (S12) output from the light receiving section. The control section (13) performs feedback control when the light receiving level is in a first range. The control section (13) adjusts the operation amount according to a first adjustment value and a second adjustment value stored in the storage section (14) when the light receiving level is greater than or equal to a prescribed value (X1) greater than the first range or less than or equal to a prescribed value (X2) less than the first range.

Description

Technical Field

[0001] This disclosure relates to a displacement sensor. Background Technology

[0002] Currently, displacement sensors are known to use the principle of triangulation to measure the displacement, surface shape, etc. of an object (see, for example, Patent Document 1). Such displacement sensors illuminate the object from a projection section, and a light-receiving section such as an image sensor receives the reflected light from the object, outputting a measurement value signal obtained based on the received light signal to measure the object's displacement, surface shape, etc. Existing technical documents Patent documents

[0003] Patent Document 1: Japanese Patent Application Publication No. 2013-011566 Summary of the Invention The problem that the invention aims to solve

[0004] In cases where reflectivity changes abruptly at each measurement site of the object, the amount of light received eventually stabilizes after multiple feedback adjustments, thus requiring measurements that undergo multiple feedback adjustments. However, if the structure is designed to simply perform multiple feedback adjustments, the adjustment time required until the amount of light received stabilizes raises concerns about obtaining accurate measurement results during the transition period. Solution for solving the problem

[0005] One aspect of the displacement sensor control disclosed herein includes: a light-emitting unit comprising a light-emitting element for emitting light onto a detected object and a light-emitting control circuit for controlling the light-emitting element; a light-receiving unit comprising an image sensor for receiving reflected light from the detected object and a light-receiving control circuit for controlling the image sensor, and outputting an image signal corresponding to the reflected light received by the image sensor; a control unit for performing feedback control, adjusting an operational quantity including at least one of the light-emitting amount of the light-emitting element and the light-receiving amount of the image sensor based on the light-receiving level of the image signal; and a storage unit for storing adjustment values ​​for the operational quantity, wherein the control unit is configured to perform the feedback control when the light-receiving level is within a first range. The effects of the invention

[0006] According to one aspect of this disclosure, a displacement sensor capable of reducing adjustment time can be provided. Attached Figure Description

[0007] Figure 1 This is a block diagram showing the electrical structure of the displacement sensor. Figure 2This is a flowchart of the light input / output feedback control. Figure 3 This is a flowchart of the process for adjusting the amount of light received. Figure 4 This is an explanatory diagram showing the operation of the displacement sensor. Figure 5 This is an explanatory diagram showing the operation of the displacement sensor. Figure 6 This is an explanatory diagram showing the processing of the displacement sensor. Figure 7 This is an explanatory diagram showing the processing of the displacement sensor. Figure 8 This is an explanatory diagram showing the processing of the displacement sensor. Figure 9 This is an explanatory diagram showing the processing of the displacement sensor. Figure 10 This is an explanatory diagram showing the processing of the displacement sensor. Figure 11 This is an explanatory diagram showing the processing of the displacement sensor. Detailed Implementation

[0008] Hereinafter, one embodiment will be described with reference to the accompanying drawings. Figure 1 The displacement sensor 10 shown projects the detection light L1 onto the object being detected W to detect the displacement, shape, etc. of the object being detected W.

[0009] like Figure 1 As shown, the displacement sensor 10 has a light-emitting unit 11, a light-receiving unit 12, a control unit 13, a storage unit 14, and an input / output unit 15. The light-projecting unit 11 includes a light-projecting element 11a and a light-projection control circuit 11b. The light-receiving unit 12 includes an image sensor 12a and a light-receiving control circuit 12b. The light-projecting element 11a projects detection light L1 toward the object being detected W. The light-projecting element 11a is, for example, a laser diode. The light-projection control circuit 11b controls the light-projecting element 11a. The detection light L1 projected from the light-projecting element 11a is reflected by the object being detected W. The reflected light L2 enters the image sensor 12a of the light-receiving unit 12.

[0010] like Figure 4 , Figure 5 As shown, the image sensor 12a has a plurality of light-receiving units 12s. The image sensor 12a in this embodiment is a CMOS image sensor. Alternatively, a CCD image sensor, PSD, or other element having a plurality of light-receiving units 12s can be used as the image sensor 12a. The image sensor 12a converts the reflected light L2 received by each light-receiving unit 12s into an electrical signal with a voltage level corresponding to the amount of light received by the reflected light L2 and outputs it.

[0011] The light-receiving control circuit 12b controls the image sensor 12a. The light-receiving control circuit 12b generates an electrical signal output from the image sensor 12a, which corresponds to the amount of reflected light L2 received by the image sensor 12a. The light-receiving unit 12 outputs this image signal S12. The image signal S12 includes the light-receiving level of each light-receiving unit 12s of the image sensor 12a. The light-receiving level is a value proportional to the amount of light received by each light-receiving unit 12s. In other words, the image signal S12 is a time-sequential signal (light-receiving waveform) corresponding to the distribution of light received on the light-receiving surface of the image sensor 12a.

[0012] The control unit 13 detects the position of the light-receiving center of the reflected light L2 in the image sensor 12a based on the image signal S12 from the light-receiving unit 12. Furthermore, the control unit 13 determines the displacement of the object W being detected based on this light-receiving center position.

[0013] like Figure 4 As shown, the displacement sensor 10 has a projection lens 21 and a receiving lens 22. Detection light L1 projected from the projection element 11a passes through the projection lens 21 and illuminates the object W being detected. Reflected light L2, after being reflected by the object W, passes through the receiving lens 22 and enters the image sensor 12a. The image sensor 12a has multiple receiving units 12s.

[0014] The control unit 13 detects the light-receiving center position O1 of the reflected light L2 reflected by the object W (shown by the solid line). For example, the control unit 13 detects the position of the light-receiving unit 12s that has the highest light-receiving level (light-receiving amount) in the image signal S12 as the light-receiving center position O1. In addition, in the image signal S12, if the light-receiving amount of multiple light-receiving units 12s is saturated, the control unit 13 detects the positions of the multiple light-receiving units 12s that have reached the saturation value as the light-receiving center position O1.

[0015] Next, when the object to be detected W moves to the position indicated by the dashed line, the reflected light L2 reflected by the object to be detected W enters the image sensor 12a at a position different from that indicated by the solid line. That is, the light-receiving center position O2 changes according to the distance from the displacement sensor 10 to the surface of the object to be detected W. The control unit 13 detects the light-receiving center position O2 of the reflected light L2. The difference between the light-receiving center positions O1 and O2 corresponds to the displacement amount of the object to be detected W. In addition, by moving the object to be detected W relative to the displacement sensor 10 in a direction orthogonal to the optical axis of the detection light L1, it is also possible to detect the presence or absence of the object to be detected, the surface shape of the object to be detected, etc.

[0016] The input / output unit 15 is configured to communicate with an external device connected to the displacement sensor 10. The communication can be wired or wireless. For example, the input / output unit 15 transmits the detection results from the control unit 13 to the external device. Additionally, the input / output unit 15 receives control signals, setpoints, etc., for the displacement sensor 10.

[0017] The storage unit 14 stores various information during the various processing operations of the control unit 13. The information stored in the storage unit 14 includes the setpoint and change values ​​of the displacement sensor 10. The setpoint and change values ​​are values ​​used to adjust the light emission amount of the light-emitting element 11a and the light reception amount of the image sensor 12a. Values ​​for adjusting the light emission amount include, for example, the light emission time for driving the light-emitting element 11a and the driving voltage supplied to the light-emitting element 11a. Values ​​for adjusting the light reception amount include, for example, the exposure time of the light-receiving unit 12 and the magnification rate for amplifying the signal output from the light-receiving unit 12. Furthermore, the setpoint and change values ​​include initial values, values ​​received from external devices, and values ​​set through teach processing.

[0018] The control unit 13 has a function of performing light-attribute feedback control to adjust the light-attribute amount (light-attribute time) of the light-attribute element 11a and the light-attribute amount (exposure time) of the image sensor 12a based on the image signal S12 from the image sensor 12a. The light-attribute amount of the reflected light L2 from the image sensor 12a varies according to the reflection state of the surface of the object W being detected. As described above, the control unit 13 detects the position of the light-attribute center that receives the reflected light L2 in the image sensor 12a. When the light-attribute amount of the image sensor 12a is too high or too low, the detected position of the light-attribute center may sometimes be incorrect. Therefore, the control unit 13 adjusts the light-attribute amount in a way that keeps the light-attribute amount within the optimal value range (reference range).

[0019] The amount of light emitted can be adjusted according to the emission time of the detection light L1 emitted from the emission element 11a. The emission control circuit 11b intermittently drives the emission element 11a, making the detection light L1 pulsed. The longer the emission time of the detection light L1 is, the more light is emitted. The control unit 13 sets the emission time for the emission control circuit 11b.

[0020] The amount of light received can be adjusted according to the exposure time during which reflected light L2 enters the image sensor 12a. The light-receiving control circuit 12b controls the image sensor 12a to expose itself intermittently. If the exposure time is extended, the time during which reflected light L2 enters the image sensor 12a becomes longer, meaning that the amount of light received increases. The control unit 13 sets the exposure time for the light-receiving control circuit 12b.

[0021] In addition, the control unit 13 has the function of performing adjustment processing. Adjustment processing, for example, involves storing data for... Figure 5The processing of the adjustment value of the tested object W2 is shown. The tested object W2 has multiple parts with different reflectivities, resulting in non-uniform reflectivity. Specifically, the tested object W2 has a part WA made of a high-reflectivity material (e.g., a metal such as aluminum) and a part WB made of a low-reflectivity material (e.g., black resin).

[0022] In the case of such a test object W2, during the initial measurement when the measurement area changes from a high-reflectivity region WA to a low-reflectivity region WB, the light level is sometimes too low. Regarding such a test object W2, during the adjustment process, the control unit 13 stores a value set in a manner that brings the light received by the image sensor 12a close to its optimal range as a first adjustment value in the storage unit 14. Therefore, in the case of excessive light level, by adjusting at least one of the operating amount, i.e., the amount of light emitted and the amount of light received, according to the first adjustment value stored in the storage unit 14, the time spent adjusting the amount of light received can be shortened.

[0023] Furthermore, in the object W2 being tested, during the initial measurement where the measurement area changes from a low-reflectivity region WB to a high-reflectivity region WA, the reflectivity of the measurement area sometimes changes abruptly, resulting in excessive light exposure. For such an object W2, during the adjustment process, the control unit 13 stores a value set in the storage unit 14 as a second adjustment value to bring the light exposure of the image sensor 12a close to its optimal range. Therefore, in cases where the light exposure level is too low, by adjusting at least one of the operating amount, i.e., the amount of light emitted and the amount of light received, according to the second adjustment value stored in the storage unit 14, the time spent adjusting the amount of light received can be shortened.

[0024] [Adjustments / Processing] Figure 3 This demonstrates the adjustment process for the amount of light received. First, in step 51, the first workpiece is set. The first workpiece is a high-reflectivity workpiece. For example, set... Figure 5 The part WA of the object W2 shown is taken as the first workpiece.

[0025] Next, in step 52, the control unit 13 performs feedback control on the amount of light received by the first workpiece. Next, in step 53, the control unit 13 determines whether the amount of light received is optimal based on the light level. That is, the control unit 13 determines whether the amount of light received after adjustment through the feedback control in step 52 is optimal. If the amount of light received is optimal (determination: yes), the process moves to step 54.

[0026] In step 54, the control unit 13 saves the light level corresponding to the adjusted light amount as the adjustment value (first adjustment value) for the first workpiece. For example, the control unit 13 stores the first adjustment value in... Figure 1 Storage section 14.

[0027] Next, in step 55, a second workpiece is set. The second workpiece is a low-reflectivity workpiece. For example, setting... Figure 5 The part WB of the object being tested, W2, is shown as the second workpiece.

[0028] Next, in step 56, the control unit 13 performs feedback control on the amount of light received by the second workpiece. Next, in step 57, the control unit 13 determines whether the amount of light received is optimal based on the light level. That is, the control unit 13 determines whether the amount of light received after adjustment through the feedback control in step 56 is optimal. If the amount of light received is optimal (determination: yes), the process moves to step 58.

[0029] In step 58, the control unit 13 saves the light level corresponding to the adjusted light amount as the adjustment value (second adjustment value) for the second workpiece. For example, the control unit 13 stores the second adjustment value in... Figure 1 Storage section 14.

[0030] Then, the control unit 13 finishes the adjustment process. If the light intake is not optimal in step 53 (determination: No), control unit 13 moves to step 59. In step 59, control unit 13 determines whether the light intake can be adjusted. If the light intake can be adjusted (determination: Yes), control unit 13 moves to step 52 and implements feedback control. On the other hand, if the light intake cannot be adjusted (determination: No), control unit 13 moves to step 60, performs error handling, and terminates the process. For example, in error termination handling, control unit 13 via... Figure 1 The input / output unit 15 notifies the user of information such as the inability to adjust the light intensity or the inability to store the first adjustment value. Additionally, during error termination processing, error information can be displayed on a display unit (not shown).

[0031] Furthermore, if the light intake is not optimal in step 57 (determination: No), the control unit 13 moves to step 61. In step 61, the control unit 13 determines whether the light intake can be adjusted. If the light intake can be adjusted (determination: Yes), the control unit 13 moves to step 56 and implements feedback control. On the other hand, if the light intake cannot be adjusted (determination: No), the control unit 13 moves to step 62, performs error handling, and terminates the process. For example, in the error termination process, the control unit 13, via... Figure 1 The input / output unit 15 notifies the user of information such as the inability to adjust the light intensity or the inability to store a second adjustment value. Additionally, during error termination processing, error information can be displayed on a display unit (not shown).

[0032] [Light input / output feedback control] Figure 2 This demonstrates the feedback control of the amount of light received. First, in step 31, the control unit 13 acquires the light level.

[0033] Next, in step 32, the control unit 13 determines whether the amount of light received is within the optimal range based on the light level. If the amount of light received is within the optimal range (determination: yes), the control unit 13 moves to step 31. On the other hand, if the amount of light received is not within the optimal range (determination: no), the control unit 13 moves to step 33.

[0034] In step 33, the control unit 13 determines whether the adjustment is effective. For example, in Figure 1 The storage unit 14 shown stores pattern information. The pattern information includes a flag indicating whether the adjustment is valid or invalid. The control unit 13 determines whether the adjustment is valid based on the pattern information. If the adjustment is valid (determination: yes), the control unit 13 moves to step 34; if the adjustment is invalid (determination: no), it moves to step 38. Alternatively, the control unit 13 can also... Figure 1 In the storage unit 14 shown, the adjustment is deemed invalid if at least one of the first adjustment value and the second adjustment value is a predetermined value. The predetermined value can be, for example, a value that cannot be set to either the first adjustment value or the second adjustment value, such as "0".

[0035] In step 34, the control unit 13 determines whether the light-receiving level is above or equal to a predetermined value X1. The predetermined value X1 is a first level that is larger than the optimal value range. This first level is a saturation level or a level close to a saturation level. If the light-receiving level is above or equal to the predetermined value X1 (determination: yes), the control unit 13 proceeds to step 35.

[0036] In step 35, the control unit 13 adjusts the amount of light received. At this time, the control unit 13 uses the saturation setting value, that is, the first adjustment value set for a workpiece with high reflectivity. The control unit 13 then... Figure 1 The storage unit 14 reads a first adjustment value and adjusts the light emission amount for the light-emitting unit 11 and the light reception amount for the light-receiving unit 12. The first adjustment value includes an adjustment value for at least one of the light emission amount and the light reception amount as an operational quantity. The control unit 13 adjusts the light emission and reception amounts based on the first adjustment value.

[0037] If the amount of light received is adjusted, the control unit 13 moves to step 31. In step 34, if the light level is less than the specified value X1 (determination: no), the control unit 13 moves to step 36.

[0038] In step 36, the control unit 13 determines whether the light-receiving level is below a predetermined value X2. The predetermined value X2 is a second level smaller than the optimal value range. This second level is close to zero. If the light-receiving level is below the predetermined value X2 (determination: yes), the control unit 13 moves to step 37.

[0039] In step 37, the control unit 13 adjusts the amount of light received. At this time, the control unit 13 uses a setting value with no light received, that is, it uses a second adjustment value set for a workpiece with low reflectivity. The control unit 13 then... Figure 1 The storage unit 14 reads the second adjustment value and adjusts the light emission amount for the light-emitting unit 11 and the light reception amount for the light-receiving unit 12. The second adjustment value includes an adjustment value for at least one of the light emission amount and the light reception amount as an operational quantity. The control unit 13 adjusts the light emission and reception amounts based on the second adjustment value.

[0040] If the amount of light received is adjusted, the control unit 13 moves to step 31. In step 36, if the light level is not below the specified value X2 (determination: no), the control unit 13 moves to step 38.

[0041] In step 38, the control unit 13 determines whether the light level is greater than the optimal value range. If the light level is greater than the optimal value range (determination: yes), the control unit 13 moves to step 39.

[0042] In step 39, the control unit 13 is set to reduce the amount of light emitted and received. For example, the control unit 13 sets the light-emitting unit 11 and the light-receiving unit 12 as new settings by subtracting a predetermined change value from the current settings (light emission time, exposure time) for the light-emitting unit 11 and the light-receiving unit 12. The change value can be a constant value or a variable value.

[0043] Furthermore, the control unit 13 sets the value obtained by multiplying the current value of the light received by a coefficient (reduction coefficient) that reduces the light received amount as a new set value, and adjusts the light received amount. The reduction coefficient is, for example, a value less than 1, such as "0.8". Additionally, the reduction coefficient can be changed according to the light received level and the optimal value range. For example, the greater the difference between the light received level and the optimal value range, the smaller the reduction coefficient. Moreover, when reducing the light received amount, the control unit 13 proceeds to step 31.

[0044] On the other hand, in step 38, if the light level is below the optimal range (determination: no), the control unit 13 moves to step 40. In step 40, the control unit 13 is set to increase the amount of light emitted and received. For example, the control unit 13 sets the light-emitting unit 11 and the light-receiving unit 12 to a new setting value by adding a predetermined change value to the current settings (light emission time, exposure time) for the light-emitting unit 11 and the light-receiving unit 12. The change value can be a constant value or a variable value. In addition, the change value set to decrease the amount of light emitted and received can be the same value or different value set to increase the amount of light emitted and received.

[0045] Furthermore, the control unit 13 sets the value obtained by multiplying the current value of the light received by a coefficient (increase coefficient) that increases the light received amount as the new light received amount. The increase coefficient is, for example, a value larger than "1", such as "1.2". In addition, the increase coefficient can also be changed according to the light received level and the optimal value range. For example, the greater the difference between the light received level and the optimal value range, the larger the increase coefficient. Moreover, when increasing the light received amount, the control unit 13 moves to step 31.

[0046] (effect) Next, the function of the displacement sensor 10 in this embodiment will be explained. Figure 6 , Figure 7 The light-receiving waveform of image sensor 12a is shown. Figure 6 , Figure 7 In the diagram, the horizontal axis represents the position of the light-receiving unit 12s, and the vertical axis represents the amount of light received (light level). Figure 6 In the diagram, the shaded area H1 indicates the optimal range of values ​​for the tested object W with high reflectivity. Figure 7 In the diagram, the shaded area H2 indicates the optimal range of values ​​for the tested object W with low reflectivity. Alternatively, the optimal range can also be the same amount of light received.

[0047] Figure 6 , Figure 7 In the diagram, solid lines represent the light-receiving waveforms F11 and F21, indicating waveforms suitable for peak position detection. Single-dotted lines represent the light-receiving waveforms F12 and F22, indicating when the light intake (light level) is lower than the optimal range. In this case, the operational amount (light output, light intake) is increased to approach the light-receiving waveforms F11 and F21. Double-dotted lines represent the light-receiving waveforms F13 and F23, indicating when the light intake (light level) is higher than the optimal range. In this case, the operational amount (light output, light intake) is decreased to approach the light-receiving waveforms F11 and F21. Figure 6 In the light-receiving waveform F13 shown, the linear portion indicates the situation where the light-receiving amount is saturated in many light-receiving units 12s.

[0048] Figure 8 , Figure 9The relationship between the reflectance of the tested object W and the adjustment value is shown. Additionally, Figure 8 , Figure 9 This shows the case where the adjustment of the projection time is used as the adjustment value. Figure 8 , Figure 9 In this diagram, region H21 indicates the optimal range of light received, region H22 indicates the range of saturation, and region H23 indicates the range of insufficient light received. The range between regions H22 and H23 corresponds to the first range. In one example, the first range is a range larger than the second level of light received (defined value X2) and smaller than the first level of light received (defined value X1). In another example, the first range is set to be larger than region H21, i.e., the optimal range of light received (light level).

[0049] Figure 8 , Figure 9 In the middle, point P11 shows the measurement. Figure 5 The illumination time is shown for region WB of the tested object W2. Point P12 indicates the optimal illumination time for region WA. In its adjusted state, the illumination time is then measured. Figure 5 The image shows the location WA of the object W2 being tested. In this case, since location WA has high reflectivity, the amount of light received becomes saturated, as shown at point P21.

[0050] In the case of implementing only feedback control, by means of... Figure 9 As shown at points P21, P22, and P23, feedback control is repeatedly performed to gradually reduce the amount of light received, thereby keeping it within the optimal range. On the other hand, in the displacement sensor 10 of this embodiment, since... Figure 8 The light received at point P21 is saturated (light level), so the illumination time is adjusted in one adjustment based on the first adjustment value.

[0051] The control unit 13 obtains the light level from the image signal S12, for example, through A / D conversion (analog-to-digital conversion). When the light level is the maximum value of the input range (the maximum value of the A / D conversion), the light-receiving unit 12s is a saturated unit. The control unit 13 counts the number of saturated units and determines whether the count value (number of saturated units) is greater than or equal to a predetermined value N. The predetermined value N is set corresponding to the light level that can approach the optimal value range in a short time during feedback control that incrementally increases or decreases the light amount. For example, when the maximum value (peak value) of the light amount slightly exceeds the saturation level, multiple light-receiving units 12s become saturated units. In this case, multiple feedback controls can make the light level (light amount) smaller than the saturation value, thereby maintaining the light level within or close to the optimal value range.

[0052] On the other hand, if Figure 6If the light-receiving waveform F13, as shown by the double-dotted line, has a large number of saturation units, then the maximum value (peak value) of the light-receiving level is extremely large compared to the saturation value. Therefore, even with repeated feedback control, it is sometimes impossible to go below the saturation value.

[0053] like Figure 11 As shown, the light received is saturated at time T21. Time T22 shows the light received waveform after multiple feedback controls. In this case, the light received level is saturated. Time T23 shows the light received waveform after further multiple feedback controls. In this light received waveform, the peak value is also higher than the optimal range. However, since the peak value is identified, the peak value of the light received waveform is brought within the optimal range, as shown in the light received waveform at time T24. Thus, it takes time for the light received (light received level) to approach the optimal range.

[0054] In the displacement sensor 10 of this embodiment, when the number of saturated units is a predetermined number N or more, the operating quantity (light emission amount, light reception amount) can be easily brought within or close to the optimal value range by using the first adjustment value stored in the storage unit 14. Furthermore, since the operating quantity (light emission amount, light reception amount) can be adjusted in a single adjustment, the adjustment time can be shortened. Moreover, stable measurement results can be obtained in a short time.

[0055] Figure 10 The measurement status and light waveform are shown when multiple test objects W2 are transported. At times T11, T12, T13, T14, and T15, measure location WA, location WB, transport path, location WA, and location WB.

[0056] When the light intensity at location WA was measured at time T11, the light intensity at location WB became insufficient when measured at time T12. Therefore, as shown at time T12+1, the control unit 13 used a second adjustment value to increase the light intensity of the received waveform. Based on this received waveform, the control unit 13 was able to measure location WB.

[0057] Next, at time T13, no object W2 is detected and the reflected light from the transport path is received. Next, at time T14, the portion WA of the object W2 is measured. At this time, since the amount of light received has increased according to the second adjustment value, the light-receiving waveform of portion WA becomes saturated. Therefore, as shown at time T14+1, the control unit 13 uses the first adjustment value to reduce the amount of light received in the light-receiving waveform. Based on this light-receiving waveform, the control unit 13 is able to measure portion WA.

[0058] The control unit 13 sets a first adjustment value and a second adjustment value through the adjustment process of the amount of light received, and stores them in the storage unit 14. Therefore, in the adjustment process, by setting the object to be detected, W2, as the object to be detected, the first adjustment value and the second adjustment value can be easily set.

[0059] In the process of adjusting the amount of light received, the control unit 13 stores the adjustment value adjusted by feedback control as the first adjustment value and the second adjustment value in the storage unit 14. Therefore, it is possible to easily set and store the first adjustment value and the second adjustment value of the workpiece suitable for feedback control.

[0060] As described above, this embodiment achieves the following effects. (1) The displacement sensor 10 includes a light-emitting section 11 including a light-emitting element 11a, a light-receiving section 12 including an image sensor 12a, a control section 13, and a storage section 14. The light-receiving section 12 outputs an image signal S12 corresponding to the reflected light L2 received by the image sensor 12a from the object being detected W. The control section 13 performs feedback control, that is, it adjusts the operation amount of at least one of the light-emitting amount including the light-emitting element 11a and the light-receiving amount of the image sensor 12a based on the light-receiving level of the image signal S12 output from the light-receiving section 12. When the light-receiving level is within a first range, the control section 13 performs feedback control. When the light-receiving level is greater than or equal to a predetermined value X1 larger than the first range, or less than or equal to a predetermined value X2 smaller than the first range, the control section 13 adjusts the operation amount according to a first adjustment value and a second adjustment value stored in the storage section 14. In cases where the light level is too high or too low, the time spent adjusting the light level can be shortened by adjusting at least one of the operation amount, namely the light emission amount and the light reception amount, according to the first adjustment value and the second adjustment value stored in the storage unit 14.

[0061] (2) The control unit 13 sets a first adjustment value and a second adjustment value by adjusting the amount of light received, and stores them in the storage unit 14. Therefore, in the adjustment process, by setting the object to be detected, W2, as the object to be detected, the first adjustment value and the second adjustment value can be easily set.

[0062] (3) In the process of adjusting the amount of light received, the control unit 13 stores the adjustment value adjusted by feedback control as the first adjustment value and the second adjustment value in the storage unit 14. Therefore, it is possible to easily set and store the first adjustment value and the second adjustment value of the workpiece suitable for feedback control.

[0063] (4) The control unit 13 adjusts and sets the illumination time of the illumination unit 11. As a result, the amount of light emitted by the illumination element 11a can be easily adjusted. (5) The control unit 13 adjusts and sets the exposure time of the light-receiving unit 12. As a result, the amount of light received by the image sensor 12a can be easily adjusted.

[0064] [Example of Change] The descriptions relating to the embodiments are examples of the ways in which displacement sensors related to this disclosure can take place, and are not intended to limit the ways in which they can take place. In addition to the embodiments, this disclosure can take, for example, variations of the embodiments shown below, as well as combinations of at least two variations that do not contradict each other.

[0065] ■In the above embodiments, such as Figure 5 As shown, the object to be tested, W2, is defined as having portions WA and WB, but it can also be defined as an object to be tested having either portion WA or WB. For example, the object to be tested can be made of a low-reflectivity material, while the transport line carrying the object to be tested, the strip holding the object to be tested, etc., can be made of a high-reflectivity material. Even in such a case, the adjustment time for the amount of light received can be shortened in the same way as in the above embodiment.

[0066] • In addition to the above embodiments, the object to be tested may also have at least one of multiple regions WA and WB. Furthermore, the object to be tested may also have at least one region with a reflectivity different from regions WA and WB. • For the purposes of the initial disclosure and for the purpose of independently defining the invention described in the claims from the combination of features in the embodiments and / or claims, all features disclosed in the specification and / or claims are disclosed separately and independently. For the purposes of the initial disclosure and for the purpose of defining the invention described in the claims, especially as a limitation of numerical ranges, the description indicating the set of all numerical ranges or constituent elements discloses all possible intermediate values ​​or intermediate constituent elements. Explanation of reference numerals in the attached figures 10 Displacement Sensors 11 Light projection department 11a Radiant Element 11b Flooding Control Circuit 12 Light-receiving section 12a Image Sensor 12b Light receiving control circuit 12s light-receiving unit 12s 12s Light receiving unit 13 Control Department 14 Storage Department 15 Input / Output Section S12 image signal W and W2 are the tested substances WA parts WB area

Claims

1. A displacement sensor, comprising: The light-emitting unit includes a light-emitting element for emitting light onto the object being detected and a light-emitting control circuit for controlling the light-emitting element; The light-receiving unit includes an image sensor that receives reflected light from the object being detected and a light-receiving control circuit that controls the image sensor, and outputs an image signal corresponding to the reflected light received by the image sensor; The control unit performs feedback control and adjusts the operation amount of at least one of the light emission amount of the light-emitting element and the light emission amount of the image sensor based on the light level of the image signal. as well as The storage unit stores adjustment values ​​for the operation quantity. The control unit is configured such that, The feedback control is performed when the maximum value of the light-receiving level is within the first range. When the maximum value of the light-receiving level is greater than or equal to a first level larger than the first range, or less than or equal to a second level smaller than the first range, the operating amount is adjusted according to the adjustment value stored in the storage unit. The adjustment value includes a first adjustment value and a second adjustment value. The first adjustment value makes the maximum value of the light received level within the saturation range close to or within the reference range. The second adjustment value makes the maximum value of the light received level within the insufficient light received range close to or within the reference range. When the number of saturation units in the image signal is greater than or equal to a predetermined number, it is determined that the maximum value of the light-receiving level is greater than or equal to the first level, and the first adjustment value is set as the operation amount. When the maximum value of the light-receiving level is below a predetermined value, it is determined that the maximum value of the light-receiving level is below the second level, and the second adjustment value is set as the operation amount.

2. The displacement sensor according to claim 1, wherein, In the feedback control, the control unit controls the operation amount in such a way that the maximum value of the light-receiving level is within a reference range, wherein the first range is set to be larger than the reference range.

3. The displacement sensor according to claim 1 or claim 2, wherein, The reference range includes: a first reference range for objects with high reflectivity and a second reference range for objects with low reflectivity. The first adjustment value is one that brings the maximum value of the light-receiving level within the range of the saturation state close to or within the first reference range. The second adjustment value is a value that brings the maximum value of the light-receiving level within the range of insufficient light reception close to the second reference range or a value within the first reference range.

4. The displacement sensor according to claim 1, wherein, The control unit performs adjustment processing and stores the first adjustment value and the second adjustment value in the storage unit.

5. The displacement sensor according to claim 4, wherein, The control unit during the adjustment process The adjustment value, based on the feedback control performed on the first workpiece, is stored as the first adjustment value in the storage unit. The adjustment value after the feedback control based on the light level of the second workpiece is stored as the second adjustment value in the storage unit.

6. The displacement sensor according to claim 1, wherein, The light projection control circuit controls the light projection time of the light projection element by projecting pulsed light. The control unit adjusts the light emission time of the light emission element relative to the light emission control circuit.

7. The displacement sensor according to claim 1, wherein, The light-receiving control circuit controls the exposure time of the image sensor. The control unit adjusts the amount of light received based on the exposure time of the image sensor.

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