Optical sensor, optical sensor control method, and optical sensor control program

Abstract

To provide an optical sensor that, even when detecting a relatively distant object to be detected, does not require complicated optical axis adjustment work.SOLUTION: An optical sensor 100 comprises: a light projection element that projects detection light LT being visible light; an optical axis adjustment element that adjusts an optical axis of the detection light projected from the light projection element; a light receiving element that receives detection light reflected on an object 210 and outputs a detection signal; and a light projection adjustment unit that recognizes, as an indication direction, a specific direction in which, among detection results based on detection signals obtained by driving the optical axis adjustment element to sequentially project the detection light in a plurality of preset specific directions, a detection result evaluated such that the detection light is blocked is obtained, and adjusts a light projection direction of the detection light projected for inspection of an objected to be inspected on the basis of, the recognized indication direction.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an optical sensor, a control method for an optical sensor, and a control program for an optical sensor. [Background technology]

[0002] Optical sensors that detect the presence or absence of an object to be inspected and the distance to the object are known. For example, Patent Document 1 discloses a ToF (Time of Flight) sensor that detects the distance by measuring the time it takes for detection light projected onto the object to be reflected and returned. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-53769 A Summary of the Invention [Problem to be solved by the invention]

[0004] Optical sensors are installed in production lines and are sometimes used to measure the characteristic shapes of parts flowing through the production line to determine the type and quality of the items. When used in this way, optical sensors are often attached to structures associated with the production line 300, but they cannot always be attached near the objects to be inspected. In recent years, wide-range optical sensors with detection ranges of several meters have been developed. However, with wide-range optical sensors, even a slight angle error during installation causes the detection light to deviate from the target location of the object to be inspected. When an optical sensor is attached via a mounting fixture, it is difficult to precisely adjust the optical axis of the detection light, and workers have to perform the cumbersome task of loosening and tightening the mounting fixture while checking the spot of the detection light.

[0005] The present invention has been made to solve such problems, and provides an optical sensor etc. that does not require complicated optical axis adjustment work, even when detecting an object that is relatively far away. [Means for solving the problem]

[0006] The optical sensor according to the first aspect of the present invention includes a light-projecting element that projects a detection light, which is visible light, an optical axis adjustment element that adjusts the optical axis of the detection light projected from the light-projecting element, a light-receiving element that receives the detection light reflected by an object and outputs a detection signal, and a light-projection adjustment unit that recognizes a specific direction in which a detection result that is evaluated as the detection light being blocked is obtained as a designated direction among detection results based on detection signals obtained by sequentially projecting the detection light in a plurality of specific directions set in advance by driving the optical axis adjustment element, and adjusts the projection direction of the detection light to be projected for the inspection of the inspection object based on the recognized designated direction. According to the optical sensor configured in this way, a user can specify the projection direction of the detection light to be projected for the inspection of the inspection object by simply blocking the detection light in the specific direction with, for example, a fingertip, thereby saving the trouble of re-adjusting the orientation of the optical sensor and improving operability.

[0007] In the optical sensor described above, the light-projection adjustment unit may sequentially project light in a light-projection direction set at the time point as one cycle in addition to the multiple specific directions, and may differentiate the manner of light projection between when projecting light in the multiple specific directions and when projecting light in the light projection direction. By differentiating the manner of light projection in this way, the user can easily recognize the role of each detection light projected from one light-projecting element.

[0008] In the optical sensor described above, each of the plurality of specific directions may be set at an end of a range that can be adjusted by the optical axis adjustment element, so that a user can easily recognize within what range the detection light projected for inspecting the inspection object can be adjusted.

[0009] In the optical sensor described above, if there is a specific direction in which the light receiving element cannot detect the reflected detection signal among a plurality of specific directions set in advance, the light projection adjustment unit may move the specific direction to a direction in which the detection signal can be detected. By moving the specific direction in this manner, the detection light in any specific direction forms a spot on the target object, making it easier for the user to find the optical axis of the detection light in the specific direction and to give a directional instruction.

[0010] In the optical sensor described above, the light projection adjustment unit may move the plurality of specific directions based on at least one of a plurality of predetermined specific directions or the distance to the object detected in the light projection direction. By moving in this manner, the intervals between the detection lights in the specific directions can be appropriately maintained regardless of the distance from the optical sensor, so that the user can easily give a direction instruction. In this case, if the plurality of specific directions are not the ends of the range that can be adjusted by the optical axis adjustment element, the light projection adjustment unit may project light in the end direction to indicate the range. By projecting light in the end direction in this manner, the user can easily recognize the range within which the detection light projected for inspection of the inspection object can be adjusted.

[0011] In the optical sensor described above, the light projection adjustment unit may adjust the projection direction of the detection light to be projected for inspecting the inspection object based on the order in which the two or more specific directions are blocked when a detection result is obtained in which the detection light projected in each of the multiple specific directions is evaluated as being successively blocked in sequence. This aspect also allows the user to intuitively and easily give direction instructions. In this case, when the light projection adjustment unit adjusts the light projection direction based on the order in which the light is blocked, the light projection adjustment unit may stop adjusting the light projection direction for a preset set time. By providing such a stop period, it is possible to prevent erroneous detection due to the reciprocating movement of the user's hand.

[0012] In the optical sensor described above, the light projection adjustment unit may confirm the light projection direction when all of the detection results obtained by sequentially projecting light in a plurality of specific directions are evaluated as detection results in which the detection light is blocked. If a confirmation instruction is received consecutively to a direction instruction in this manner, the user does not need to operate the optical sensor to issue a confirmation instruction, which is expected to improve operability.

[0013] In the optical sensor described above, the light-projection adjustment unit may determine the light-projection direction when a preset combination of detection light among detection results obtained by sequentially projecting light in a plurality of specific directions is evaluated as being blocked. The light-projection adjustment unit may also project detection light as a determination light for receiving a determination instruction, and determine the light-projection direction when a detection result is evaluated as being blocked for the detection light of the determination light. Even in this mode, the user does not need to operate the optical sensor to give a determination instruction, and workability is expected to be improved.

[0014] In the optical sensor described above, the plurality of specific directions may be set for each of a plurality of discrete points defined so as to cover at least a part of the range adjustable by the optical axis adjustment element, and the light projection adjustment unit may recognize the specific direction in which the detection light is evaluated as being most closely blocked as the indicated direction, and may determine the light projection direction as the indicated direction. With such an indication method, the light projection direction can be indicated more directly.

[0015] A control method for an optical sensor in a second aspect of the present invention is a control method for an optical sensor including a light-projecting element that projects detection light, an optical axis adjustment element that adjusts the optical axis of the detection light projected from the light-projecting element, and a light-receiving element that receives the detection light reflected by an object and outputs a detection signal, and includes a light-projecting step of sequentially projecting the detection light in a plurality of predetermined specific directions by driving the optical axis adjustment element, a recognition step of recognizing as a pointed direction a specific direction in which a detection result that indicates that the detection light is blocked is obtained among detection results based on detection signals obtained by projecting light in each of the plurality of specific directions in the light-projecting step, and an adjustment step of adjusting the projection direction of the detection light to be projected for inspection of the object to be inspected based on the pointed direction recognized in the recognition step.

[0016] In addition, a control program for an optical sensor in a third aspect of the present invention is a control program for an optical sensor including a light-projecting element that projects detection light, an optical axis adjustment element that adjusts the optical axis of the detection light projected from the light-projecting element, and a light-receiving element that receives the detection light reflected by an object and outputs a detection signal, and causes a computer to execute a light-projecting step of sequentially projecting the detection light in a plurality of predetermined specific directions by driving the optical axis adjustment element, a recognition step of recognizing as a pointed direction a specific direction in which a detection result that indicates that the detection light is blocked is obtained among detection results based on detection signals obtained by projecting light in each of the plurality of specific directions in the light-projecting step, and an adjustment step of adjusting the projection direction of the detection light to be projected for inspection of the object to be inspected based on the pointed direction recognized in the recognition step.

[0017] In the second and third aspects, like the first aspect, the direction of the detection light to be projected for inspecting the object to be inspected can be easily indicated, eliminating the need to readjust the orientation of the optical sensor and improving operability. Effect of the Invention

[0018] According to the present invention, it is possible to provide an optical sensor or the like that does not require complicated optical axis adjustment work even when detecting a detection target that is relatively far away. [Brief description of the drawings]

[0019] [Figure 1] FIG. 2 is a perspective view of the appearance of an optical sensor. [Diagram 2] FIG. 1 is a system configuration diagram of an optical sensor. [Diagram 3] 11A and 11B are diagrams illustrating the projection of command light and adjustment light onto a preliminary workpiece. [Figure 4] 13A and 13B are diagrams illustrating an adjustment method in which the adjustment light projection is moved to the right. [Diagram 5] 13A and 13B are diagrams illustrating an adjustment method in which the adjusted light projection is moved downward. [Figure 6] 11A and 11B are diagrams illustrating a method for determining the projection direction of the adjusted light as the inspection direction. [Figure 7] FIG. 1 is a diagram showing a state in which an inspection object is inspected. [Figure 8] 11A and 11B are diagrams illustrating a state in which the projection direction of the pointing light is automatically adjusted in accordance with the shape of the target object. [Figure 9] 11A and 11B are diagrams illustrating how the projection direction of the pointing light is automatically adjusted according to the distance to the target object. [Figure 10] FIG. 13 is a diagram showing a state in which boundary light is cast in addition to designated light cast. [Figure 11] 13A and 13B are diagrams illustrating another instruction method for moving the adjusted light projection. [Figure 12] 13A and 13B are diagrams illustrating another method for determining the projection direction of the adjusted light as the inspection direction. [Figure 13] 11A and 11B are diagrams illustrating an adjustment method for directly determining the inspection direction without projecting an adjustment light. [Figure 14] FIG. 4 is a flowchart illustrating a processing procedure of a control unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The present invention will be described below through embodiments of the invention, but the invention according to the claims is not limited to the following embodiments. Furthermore, not all of the configurations described in the embodiments are necessarily essential as means for solving the problems.

[0021] FIG. 1 is an external perspective view of an optical sensor 100. The optical sensor 100 according to this embodiment is a sensor that detects the presence or absence of a partial shape of a workpiece as an inspection target, the distance to a specific location, etc., and is installed and used, for example, on a production line in a factory. The optical sensor 100 projects detection light L1 toward the workpiece and receives detection light L2 that is reflected by the workpiece and returns. The optical sensor 100 described below is a ToF sensor that detects distance information by measuring the round-trip time of the detection light in particular. When the optical sensor 100 cannot receive the detection light L2, it outputs non-detection information indicating that the workpiece is not detected, and when it can receive the detection light L2, it outputs distance information.

[0022] The detection light L1 is projected through a transparent window 102 provided on one surface of the housing 101. Although details will be described later, the optical sensor 100 is provided with an optical axis adjustment element that adjusts the projection direction of the detection light L1 projected from the light projecting element. The optical axis adjustment element can deflect the optical axis of the detection light L1 in two axial directions (X-axis direction and Y-axis direction shown in the figure) that are orthogonal at a predetermined pitch. Specifically, the optical axis of the detection light L1 can be deflected in any direction (x m ,y n ) so that the optical axis of the detection light L1 can be aligned with the

[0023] In addition, the optical sensor 100 is arranged in a direction D along the projection direction of the detection light L1. n From D f In other words, the range indicated by the dots in the figure is the detectable range V, and the optical sensor 100 outputs non-detection information if a workpiece is not present within this range, and outputs distance information to the reflection point of the detection light L1 if a workpiece is present within this range.

[0024] An operation button 150 is provided on one surface of the housing 101, and the operation button 150 accepts operations from the user. A display panel 160 is also provided on one surface of the housing 101, and the display panel 160 displays the confirmed inspection direction and the like, as described below. A cable 103 is connected to an external device such as a PLC or a PC, and transmits an output signal to these devices. Note that an X-axis, a Y-axis, and a Z-axis are defined as shown in the figure. In the following drawings, the same coordinate axes as in FIG. 1 are also shown to indicate the orientation of the components depicted in each drawing.

[0025] 2 is a system configuration diagram of the optical sensor 100. The control system of the optical sensor 100 is mainly composed of a control unit 110, a light projecting element 120, an optical axis adjustment element 130, a light receiving element 140, an operation button 150, a display panel 160, an input / output IF 170, and a storage unit 180. The control unit 110 is a processor (CPU: Central Processing Unit) that controls the optical sensor 100 and executes programs. The control unit 110 may be configured to include an arithmetic processing chip such as an ASIC (Application Specific Integrated Circuit) and a processing circuit that processes various electrical signals. The control unit 110 executes a control program that is read from the storage unit 180 or provided from an external device via the input / output IF 170, and performs various processes related to the detection process of the workpiece.

[0026] The light projecting element 120 is a laser diode that emits laser light in a wavelength band that is visible light (for example, red light of 635 nm to 680 nm), and emits detection light L1 modulated to a specific frequency (for example, 12 MHz) under the control of the control unit 110. Note that the light projecting element 120 is not limited to a laser diode that emits coherent light, and an element that emits incoherent light, such as an LED, may be used.

[0027] As described above, the optical axis adjustment element 130 is an element that adjusts the optical axis of the detection light L1 projected from the light projecting element 120. In this embodiment, a liquid crystal device that realizes deflection by applying a voltage to a liquid crystal cell and controlling the on / off state is used as the optical axis adjustment element 130. Specifically, the liquid crystal device is a device in which a liquid crystal diffraction grating in which liquid crystal cells are arranged (for example, Journal of Optics, Vol. 30, No. 1: "Research Trends in Liquid Crystal Optical Devices," p. 6) is stacked, and a control circuit is incorporated that controls the voltage applied to the liquid crystal cell so that the amount of deflection of the incident laser light can be controlled according to an input control signal. In addition, as the optical axis adjustment element 130, a MEMS mirror, an optical phased array, an electro-optical crystal, etc. can also be used.

[0028] The light receiving element 140 is, for example, a CMOS sensor having photoelectric conversion pixels arranged two-dimensionally, and converts the received detection light L2 into an electric signal and transmits it to the control unit 110. In the figure, the optical paths of the detection light L1 projected toward the work and the detection light L2 received by the light receiving element 140 are shown separately, but in reality, as shown in FIG. 1, they are the same optical path, and the optical path of the detection light L2 toward the light receiving element 140 is separated from the optical path of the detection light L1 using, for example, a dichroic mirror. In addition, since the optical axis adjustment element 130 is housed in the housing 101 together with the light projecting element 120 and the light receiving element 140, there is no need to provide a movable part for adjusting the optical axis of the detection light L1 outside the housing 101. Therefore, since the housing 101 can be directly fixed to, for example, a structure associated with the manufacturing line, the optical sensor 100 is easy to install and is less susceptible to the influence of inadvertent contact by an operator.

[0029] The operation button 150 is an operation member that accepts designation from the user, and may include, for example, an UP button, a DOWN button, a cross button, etc. The operation button 150 cooperates with the control unit 110 to function as a reception unit that accepts input of various items of the optical sensor 100. Note that the operation member is not limited to the operation button, and may be another device such as a touch sensor.

[0030] The display panel 160 is, for example, a liquid crystal panel, and displays the setting state of the optical sensor 100, distance information as a detection result, non-detection information, and the like. An LED or the like may be provided as a device indicating the setting state of the optical sensor 100. The input / output IF 170 is an interface for transmitting and receiving information to and from an external device via the cable 103, and includes, for example, an Ethernet (registered trademark) unit or a LAN unit. The input / output IF 170 is not limited to a wired connection via the cable 103, and may include a wireless connection unit compatible with wireless LAN or Bluetooth (registered trademark).

[0031] The control unit 110 can also receive operations performed by a user on an external operation panel and control signals output by a PLC, which is an external device, via the input / output IF 170. For example, when a user operates the operation panel to give an instruction to start inspecting a workpiece, the input / output IF 170 cooperates with the control unit 110 to function as a reception unit that receives the instruction to start inspection.

[0032] The storage unit 180 is a non-volatile storage medium, and is configured by, for example, a flash memory. The storage unit 180 can store various parameter values, functions, lookup tables, and the like used for control and calculation, in addition to programs for executing control and processing of the optical sensor 100. The storage unit 180 also stores the initial detection distance detected at the start of the adjustment mode and the confirmed inspection direction of the detection light L1.

[0033] The control unit 110 also plays a role as a functional calculation unit that executes various calculations according to the processing instructed by the control program. The control unit 110 can function as a light projection adjustment unit 111 and a distance calculation unit 112. The light projection adjustment unit 111 recognizes a specific direction in which a detection result that the detection light L1 is interrupted is obtained among the detection results obtained by driving the optical axis adjustment element 130 to sequentially project the detection light L1 in a plurality of specific directions set in advance as a designated direction, and adjusts the projection direction of the detection light L1 to be projected for the inspection of the inspection work based on the recognized designated direction. In addition, when inspecting the inspection work, the optical axis adjustment element 130 is driven so that the detection light L1 is projected in the inspection direction adjusted and determined in this way. The distance calculation unit 112 calculates the time difference between the projected detection light L1 and the received detection light L2, for example, using the phase difference between the two, and converts it into the distance to the preliminary work or the inspection work. The control unit 110 can convert the calculation result of the distance calculation unit 112 into a data structure and output it as distance information. Alternatively, when the light receiving element 140 does not receive the detection light L2, the control unit 110 can output defined non-detection information.

[0034] The user switches the optical sensor 100 to an adjustment mode via the operation button 150 or the like, and performs an adjustment operation to determine the inspection direction in which the detection light L1 should be directed. The procedure will be specifically described below.

[0035] FIG. 3 shows the projection of the light I U , I R , I D , I L and adjust the light emission L T 1 is a diagram for explaining the projection of light from the optical sensor 100. The optical sensor 100 is fixed to a structure associated with the production line, facing the vicinity of an inspection position on the production line 300. The user places a preliminary workpiece 210, which is a spare object of the same type as the object to be inspected, on the production line 300 so that a target inspection point 211 is located near the inspection position. Here, the inspection point 211 only needs to be included in the deflectable range of the detection light L1, and the user can place the preliminary workpiece 210 on the production line 300 in an approximate location without paying much attention.

[0036] It is preferable that the preliminary work 210 is a reference product in a state where the inspection point 211 is judged to be good. In this embodiment, it is assumed that each work that is conveyed in sequence on the production line 300 is inspected to ensure that the hexagonal screw is properly fastened. In this case, the inspection point 211 is the head of the hexagonal screw, and it is preferable that the hexagonal screw is also properly fastened in the preliminary work 210.

[0037] In this state where the optical sensor 100 and the preliminary workpiece 210 are placed, the user operates the operation button 150 or the like to switch the optical sensor 100 to the adjustment mode. When the optical sensor 100 is switched to the adjustment mode, the instruction light projection I U , I R , I D , I L and adjust the light emission L T The adjustment light emission L is executed sequentially and repeatedly. T is a light to be adjusted that is projected toward a tentative inspection direction in order to determine the projection direction (inspection direction) of the detection light L1 for inspecting the inspection object. T is directed to the center of the deflection range R, for example, at the start of the adjustment mode.

[0038] Pointing Light I U , I R , I D , I L The user can adjust the light emission level T In this embodiment, the instruction light projection I is projected in the four directions of the deflection range R in order to receive an instruction to adjust the projection direction of the instruction light projection I. U is the midpoint of the upper boundary of the deflection range R, and the target light I R is the midpoint of the right side of the boundary of the deflection range R, and the target light I D is the center point of the lower boundary of the deflection range R, and the target light I Lare projected toward the midpoint of the left side of the boundary of the deflectable range R. That is, in this embodiment, four directions, up, down, left, and right, which are the ends of the adjustable range with respect to the center of the deflectable range R, are set as the multiple specific directions in which the instruction light is projected. Note that the multiple specific directions are not limited to this, and for example, the directions of the four corners of the boundary of the deflectable range R may be set, or eight directions may be set by adding the four directions of this embodiment to these.

[0039] The light projection adjustment unit 111 sequentially deflects the detection light L1 emitted from the light projection element 120 to project the instruction light I U → Pointing light I R → Pointing light I D → Pointing light I L → Adjustment light L T The light projection is repeated in a cycle of 0.01 seconds. Specifically, the light projection is switched in sequence so that each light projection lasts for, for example, 0.01 seconds. Since the detection light L1 is visible light, the user can see the spots SP formed on the preliminary workpiece 210 by these light projections. U , S.P. R , S.P. D , S.P. L , S.P. T At the start of the adjustment mode, the spot SP T SP U , S.P. R , S.P. D , S.P. L Adjust the light source L so that it is located in the center of the enclosed area, especially the enclosed area. T The direction of projection of the instruction light I may be adjusted. When adjusted in this way, the user can U , I R , I D , I L and adjust the light emission L T The role of Spot SP can be intuitively understood, and the subsequent adjustments can be T Even if the adjustment light emission L T The amount and direction of deflection can be easily grasped.

[0040] Here, the light projection adjustment unit 111 adjusts the light projection L T Spot SP Tand Pointing Light I U , I R , I D , I L Spot SP U , S.P. R , S.P. D , S.P. L Adjust the light projection L so that T and Pointing Light I U , I R , I D , I L Specifically, the light projection of the light projecting element 120 is controlled in cooperation with the control unit 110 to adjust the light projection L. T By varying the manner of light projection in this manner, the user can easily recognize the role of each light projection, even though the detection light L1 is projected from a single light-projecting element 120.

[0041] When the adjustment mode is started, the light projection adjustment unit 111 adjusts the instructed light projection I U , I R , I D , I L The distance calculation unit 112 calculates the distance for each of the above. The light projection adjustment unit 111 uses the results of these calculations as the initial detection distance D U , D R , D D , D L and stores it in the storage unit 180.

[0042] Figure 4 shows the adjusted light projection L T 11 is a diagram for explaining an adjustment method in the case where the instruction light projection I is moved to the right direction. When the adjustment mode is started as described above, the light projection adjustment unit 111 continues to adjust the instruction light projection I U → Pointing light I R → Pointing light I D → Pointing light I L → Adjustment light L T The distance calculation unit 112 repeats the projection of the instruction light I U , I R , I D , I LThe detection distances for the target object and target object are calculated in synchronization with each light projection. In this state, the user points his / her index finger at the target object as shown in the figure. R When the spot is inserted into the optical path, R is formed on the user's index finger, and the pointing light I R The pointer light I is blocked by the index finger and does not proceed further back (indicated by the broken line). R About the distance D to the index finger R ' is calculated.

[0043] When the calculation result is handed over to the light projection adjustment unit 111, the light projection adjustment unit 111 determines the initial detection distance D R From a comparison with the above, the target light I R is evaluated as being blocked. R is projected toward the right side of the center of the deflection range R, the light projection adjustment unit 111 determines, based on the evaluation result, the adjusted light projection L T The user points his / her index finger at the target point and deflects the light to the right by a preset amount. R If you stick it out into the light path of the adjustment light source for a while, T is gradually deflected to the right and eventually reaches above the inspection point 211. The user waits for the right timing to point the index finger toward the inspection point I R Remove the sensor from the optical path.

[0044] Figure 5 shows the adjusted light projection L T 4 is a diagram for explaining an adjustment method in the case where the user moves the index finger in the direction of the pointing light I D When the spot is inserted into the optical path, D is formed on the index finger of the user, and the distance calculation unit 112 projects the instruction light I D About the distance D to the index finger D ' is calculated.

[0045] When the calculation result is handed over to the light projection adjustment unit 111, the light projection adjustment unit 111 determines the initial detection distance D D From a comparison with the above, the target projection I D is evaluated as being blocked. Dis projected downward from the center of the deflection range R, the light projection adjustment unit 111 determines the adjusted light projection L T The user points his / her index finger downward from the current direction of the light projection by a preset amount of deflection. D If you stick it out into the light path of the adjustment light source for a while, T is gradually deflected downward and eventually reaches the inspection point 211. The user waits for the right timing to point the index finger toward the inspection point I D Remove the sensor from the optical path.

[0046] Figure 6 shows the adjusted light projection L T FIG. 1 is a diagram for explaining a method for determining the projection direction of the adjusted light L as the inspection direction. T When the light projection direction reaches the inspection point 211, the light projection direction is confirmed as the inspection direction. Specifically, for example, as shown in the figure, the confirmation button of the operation button 150 is pressed to confirm the direction. T When the light projection direction is determined as the inspection direction, the light projection adjustment unit 111 calculates the direction coordinate (x T ,y T ) is stored in the storage unit 180. The light projection adjustment unit 111 adjusts the adjusted light projection L T The inspection light projection L determined in a manner different from the manner of projection of C Specifically, the light projection of the light projection element 120 is controlled in cooperation with the control unit 110, and the adjusted light projection L T The light emission intensity can be increased or the light can be blinked at the inspection point 211. C is formed, and the user can confirm the location where the inspection will be performed. When the inspection direction is determined in this manner, the user can avoid the troublesome task of repeatedly loosening and tightening the mounting fixture while checking the spot of the detection light, even when detecting an object that is relatively far from the optical sensor 100.

[0047] 7 is a diagram showing the state in which an inspection workpiece 290, which is an object to be inspected, is inspected. Once the inspection direction has been determined as described above, the user removes the preliminary workpiece 210 and operates the production line 300 so that the target inspection workpieces 290 flow in sequence. Upon receiving an instruction to start inspection, the light projection adjustment unit 111 reads the direction coordinate (x T ,y T ) and read out the inspection light L C The control unit 110 fixes the projection direction of the inspection light L in that direction. C and executes the detection process, and outputs the detection result to an external device.

[0048] Here, a case will be described where the detection distance of the inspection point 221 is simply output as the detection result. As shown in the figure, a hexagonal screw is properly fastened in a certain inspection workpiece 290a, and the optical sensor 100 detects a distance D a The external device is connected to the a is within the allowable range and is judged as "passed". On the other hand, in the next inspection work 290b, the hexagonal screw is not sufficiently fastened and is floating, and the optical sensor 100 detects the distance D b The external device is connected to the b is not within the allowable range and is judged as "failed." In this manner, the optical sensor 100 can be used to judge whether the inspection work 290 is good or bad. Note that the optical sensor 100 may be configured to judge pass / fail and output the result to an external device.

[0049] Next, some modified examples will be described. Fig. 8 is a diagram showing, as a first modified example, how the projection direction of the instruction light is automatically adjusted in accordance with the shape of a preliminary workpiece 220, which is an object.

[0050] In the embodiment described with reference to FIGS. 3 to 6, the target light I U , I R , ID , I L The direction of projection of the instruction light was set to the end (boundary) of the deflectable range R. However, depending on the shape of the target object, there may be no reflective surface at the location where the instruction light is projected, making it impossible to form a spot. In such a case, the light receiving element 140 cannot detect the detection light L2, which is the reflected light, and the distance calculation unit 112 outputs a result of no distance calculation. In addition, the user cannot visually recognize in which direction the instruction light is being projected, and it is difficult to block such instruction light.

[0051] Therefore, the light projection adjustment unit 111 executes an adjustment for gradually moving the light projection direction of the instruction light resulting from the non-calculation of the distance toward the inside of the deflection possible range R. Specifically, for example, as shown in the figure, the initial instruction light projection I U When the distance calculation result is not obtained for the target object, the light projection adjustment unit 111 adjusts the target object to the target object by the instructed light projection I U The target light I is deflected downward by a preset amount. U For the purpose of the present invention, the downward direction is the center direction of the deflection possible range R. If the distance calculation result is still not obtained after the deflection, the target light projection I U This process is repeated to deflect the spot SP downward on the preliminary workpiece 210. U When the distance detection is successful, the indicator light I U This completes the adjustment of the light projection direction.

[0052] In this way, Spot SP U is formed on the preliminary workpiece 210, the distance calculation unit 112 calculates the initial detection distance D U The user can calculate the command light projection I U The optical path of the target can be recognized. R , I D , I L Similarly, when the distance cannot be calculated, the light projection direction is gradually deflected toward the center of the deflection range R, thereby executing automatic adjustment.

[0053] The direction of deflection does not have to be the center direction of the deflectable range R. Also, instruction lights other than the instruction light for which the distance calculation result is obtained may be deflected together so that each instruction light forms a spot on the preliminary work 210 while maintaining the relative relationship between up, down, left, and right. By performing automatic adjustment in this manner, all instruction lights can form a spot on the preliminary work 210, so that the user can easily find the optical path of each instruction light and easily give directional instructions.

[0054] Fig. 9 is a diagram showing a second modified example in which the projection direction of the instruction light is automatically adjusted according to the distance of the preliminary workpiece 210, which is the target. As shown in Fig. 1, the deflectable range R increases with increasing distance from the optical sensor 100. Therefore, when the production line 300 is far from the optical sensor 100, the deflectable range R with respect to the target increases, and setting the projection direction of the instruction light to the edge (boundary) of the deflectable range R often results in failure to calculate the distance. Even if the distance can be calculated, the interval between the spots formed by each increases, making it difficult for the user to perform an action to block each light path.

[0055] Therefore, the light projection adjustment unit 111 sets the instruction light projection I U , I R , I D , I L At least one of the above or adjustment light L T The direction of each light projection is adjusted based on the distance to the preliminary workpiece 210 detected by the. T The spot SP formed by T Distance D P If detected, the distance D P The specified projection frame S is determined according to the size specified in advance, and the specified projection I U , I R , I D , I L The projection direction of each of the above is adjusted to match the up, down, left and right directions of this designated projection frame S.

[0056] In this way, by setting the instruction light projection frame S inside the deflectable range R according to the distance to the preliminary workpiece 210 and adjusting the projection direction of the instruction light, it is expected that the respective spots will be formed at appropriate intervals on the preliminary workpiece 210. The user will be able to easily perform an action to block each optical path. Note that, if there is an instruction light that gives a result of distance calculation that cannot be performed even if the projection direction of the instruction light is adjusted in this way, the example of FIG. 8 may be applied to that instruction light, and the projection direction may be further adjusted.

[0057] Figure 10 shows the third modification, the pointing light I U , I R , I D , I L Plus boundary lighting P a , P b , P c , P d 9 is a diagram showing how the adjustment light projection L is performed. T Therefore, the light projection adjustment unit 111 adjusts the adjustment light projection L T I: A light for receiving movement instructions U , I R , I D , I L In addition, a guide light boundary light P is provided to indicate the adjustable range. a , P b , P c , P d Further execute the following.

[0058] As shown in the figure, if the preliminary workpiece 230 is relatively large, the boundary projection P a , P b , P c , P d are spots SP on the surface of the preliminary work 230. a , S.P. b , S.P. c , S.P. d The user can then use the spot SP a , S.P. b , S.P.c , S.P. d By visually checking the T You can recognize the range in which you can move.

[0059] The light projection adjustment unit 111 sequentially deflects the detection light L1 emitted from the light projection element 120 to, for example, direct light projection I U → Pointing light I R → Pointing light I D → Pointing light I L → Adjustment light L T → Boundary Floodlight P a → Boundary Floodlight P b → Boundary Floodlight P c → Boundary Floodlight P d The frequency of the boundary light may be reduced by, for example, setting the frequency of the boundary light to half that of the designated light. Also, the emission intensity of the boundary light may be reduced or the illumination time may be shortened relative to the designated light.

[0060] When performing boundary projection in this way, the user can use the adjustment projection L beyond the designated projection frame S in particular. T For example, as shown in the figure, the adjustment projection L is moved to the inspection point 231 located outside the designated projection frame S. T This is convenient when moving the

[0061] FIG. 11 shows a fourth modified example, in which the adjusted light projection L T 11(A) to 11(C) are diagrams for explaining another instruction method for moving the light source. In each embodiment described so far, the user recognizes the instruction direction by blocking one of the instruction lights, but in the fourth modified example, each instruction light is blocked consecutively, and the direction instruction is recognized based on the order of blocking. Fig. 11(A) to Fig. 11(C) are diagrams showing how one of the instruction lights is blocked in order over time.

[0062] Specifically, the user shakes his / her palm from top to bottom. Fig. 11(A) shows the initial stage of the shaking motion, and the pointing light I U Then, as shown in Fig. 11(B), the palm of the hand blocks the target light I.U Plus Pointing Light I R , I L Then, as shown in Figure 11(C), the palm of the hand blocks the target light I. D In addition, in Fig. 11(C), I R When the light projection adjustment unit 111 receives a calculation result from the distance calculation unit 112 that indicates that the light is successively blocked over time, it recognizes that the palm of the hand is being shook from top to bottom and adjusts the adjusted light projection L. T The light projection direction at that time is deflected downward by a preset deflection amount. Similarly, when it is recognized that the palm is waved from bottom to top, the adjusted light projection L T When it is recognized that the camera is tilted upwards and from right to left, the adjustment light emission L T When it is recognized that the camera is swung to the left, or from left to right, the adjustment light emission L T is deflected to the right by a preset deflection amount.

[0063] For example, if one tries to wave the palm from top to bottom continuously, the palm will also be waved from bottom to top continuously, so in order to avoid erroneous recognition, light projection adjustment unit 111 stops the recognition of the pointing direction for a preset time (for example, one second) after recognizing the pointing direction once. After the user waves the palm once to have the pointing direction recognized, the user returns the palm to the initial position while the recognition of the pointing direction is stopped.

[0064] FIG. 12 shows a fifth modified example, in which the adjusted light projection L T 11 is a diagram for explaining another method for determining the projection direction of the light source 10 as the inspection direction. This modification example is compatible with the fourth modification example, but is not limited thereto and can be combined with any of the previous embodiments.

[0065] In the example of FIG. 6, the adjusted light projection L T When the light projection direction reaches the inspection point 211, the user operates the operation button 150 to fix the light projection direction as the inspection direction. T After the target object reaches the inspection point 211, as shown in the figure, the target object is projected with the indicating light I U , IR , I D , I L By blocking all of the above simultaneously, the direction of light projection is determined as the inspection direction.

[0066] The light projection adjustment unit 111 is configured to project the specified light I U , I R , I D , I L When a calculation result indicating that all of the above is blocked is received from the distance calculation unit 112, the adjusted light projection L at that time is T The direction of the light projection is determined as the inspection direction. That is, the direction coordinate (x T ,y T ) is stored in storage unit 180. By accepting a confirmation instruction immediately after a direction instruction in this manner, the user does not need to operate operation button 150 of optical sensor 100 to issue a confirmation instruction, and this is expected to improve operability.

[0067] The method for detecting the confirmation instruction is the instruction projection I U , I R , I D , I L In addition to the method of detecting that all of the target light beams are blocked at the same time, various other methods can be used. For example, U , I R , I D , I L When it is detected that all of the preset combinations of the specified light projections are blocked, the adjusted light projection L at that time is T The direction of the light projection I may be determined as the inspection direction. U and I D In the combination of the above, it is considered that it is rare for simultaneous blocking to occur by accident, so when the instruction light projections of such a combination are blocked at the same time, it may be recognized as a final instruction. Also, a final light projection may be performed in addition to the instruction light projection to accept the final instruction. When the final light projection is blocked, the adjustment light projection L at that time T The direction of projection of the determining light is determined as the inspection direction. The determining light projection should be performed in a direction away from the projection direction of the command light.

[0068] FIG. 13 shows a sixth modified example, in which the adjusted light projection L T FIG. 1 is a diagram for explaining an adjustment method for directly determining the inspection direction without projecting the adjusted light L. T In order to receive the movement command, the indicator light I U , I R , I D , I L The light is projected in four directions (or more), and when any of the directions is blocked, it is deflected in a stepwise manner. M The light projection direction of the instruction light I is set for each of the lattice points defined in the deflection range R. Then, the light projection adjustment unit 111 selects the instruction light I from among them, which has a detection result that is evaluated as being the closest to the target and being blocked. M The direction of light projection is recognized as the indicated direction, and the indicated direction is immediately determined as the inspection direction.

[0069] Specifically, as shown in FIG. 13A, the light projection adjustment unit 111 drives the optical axis adjustment element 130 to sequentially deflect and project the detection light L1 in a single stroke from the upper left to the lower right of the lattice points set in the deflectable range R. The projection of each light onto the lattice points is designated as an instruction projection I. M For example, when the user wants to direct the head of a hexagonal screw, which is the inspection point 211, in the inspection direction, the user sets the instruction projection I M One of the other indicators I M The index finger is thrust out so as to block the light at a position closest to the optical sensor 100 compared to the position of the light projection adjustment unit 111. M is recognized as the indicated direction and is determined as the inspection direction for inspecting the object to be inspected.

[0070] Figure 13(B) shows the target light I M The determined inspection light projection L is different from the projection mode of C Specifically, the control unit 110 cooperates with the light projecting element 120 to control the light projection L TAccording to this adjustment method, the light emission intensity can be increased or the light can be blinked. T Since this eliminates the need to refine the light projection direction, the inspection direction can be determined more directly and in a shorter time.

[0071] In the example shown in the figure, the pointing light I M The direction of the light projection is set for each of the lattice points defined in the deflection range R, but the specified light projection I M The setting of the light projection direction is not limited to this. M The light projection direction may be set for each of a plurality of discrete points defined so as to cover at least a portion of the deflection range R.

[0072] Next, the processing procedure of the control unit 110 will be described by taking the embodiment described with reference to Fig. 3 to Fig. 7 as a representative example. Fig. 14 is a flow diagram explaining the processing procedure of the control unit 110. The flow starts when the adjustment mode is selected in a state in which the optical sensor 100 is fixed to a structure associated with the production line 300 and the preliminary work 210 is placed on the production line 300.

[0073] In step S101, the light projection adjustment unit 111 projects a command light I toward the upper boundary of the deflection range R. U →Directed light projection toward the right side of the boundary I R →Directed light projection toward the bottom edge of the border I D →Directed light projection toward the left side of the boundary I L The light projection adjustment unit 111 calculates the distance to each of the light projections by the distance calculation unit 112. The light projection adjustment unit 111 calculates the results of these calculations as the initial detection distance D U , D R , D D , D L and stores it in the storage unit 180.

[0074] Next, the process proceeds to step S102, where the light projection adjustment unit 111 adjusts the instructed light projection I U → Pointing light I R → Pointing light I D → Pointing light I LThen, in step S103, it is determined whether any of the instruction light projections has been blocked. Specifically, the detection distance D U ', D R ', D D ', D L ' is the initial detection distance D U , D R , D D , D L Whether or not it has been blocked is determined based on whether or not it has become shorter than the threshold value.

[0075] If it is determined that none of the light beams are blocked, the process proceeds to step S104, and the light projection adjustment unit 111 adjusts the adjusted light projection L T In the same direction as the previous time, the process proceeds to step S106. If it is determined that either of the lights is blocked, the light projection adjustment unit 111 adjusts the adjusted light projection L T The direction of the light is updated and the light is projected in the direction indicated by the blocked instruction light, and the process proceeds to step S106.

[0076] When the light projection adjustment unit 111 proceeds to step S106, it checks whether or not a confirmation instruction has been received via the operation button 150. If a confirmation instruction has not been received, the process returns to step S102 and the adjustment mode continues. If a confirmation instruction has been received, the adjustment light projection L at that time is T The direction of the light projection is determined as the inspection direction, and the directional coordinate (x T ,y T ) is stored in storage unit 180, the adjustment mode is ended, and the process proceeds to step S107.

[0077] When the control unit 110 receives an instruction to start the inspection in step S107, the control unit 110 T ,y T ) and read out the inspection light L C Then, the process proceeds to step S108, and the inspection light projection direction L is fixed in that direction every time the inspection workpiece 290 reaches a specified position on the production line 300. CWhen the inspection of the planned number of works flowing on the production line 300 is completed, the series of processes is completed.

[0078] The optical sensor 100 described above is not limited to a ToF sensor that detects distance information by measuring the round trip time of the detection light, but may be a triangulation sensor that detects distance information by measuring the arrival position of the reflected light that changes according to the distance of the detection object. When the optical axis adjustment element is adopted in the triangulation sensor, for example, if a lookup table that associates the measured distance with the projection direction of the detection light L1 and the receiving position of the detection light L2 is prepared in advance, distance information can be generated as a detection result. In addition, in the above-described embodiment, the detection of distance information for determining the quality of the inspection object is described, but the use of the output distance information is not limited to the quality determination. For example, a use mode in which the type of the inspection object is determined by detecting the distance to a characteristic partial shape as the inspection object may be assumed.

[0079] [Note] a light-projecting element (120) that projects detection light (L1) which is visible light; an optical axis adjustment element (130) for adjusting the optical axis of the detection light (L1) projected from the light projecting element (120); a light receiving element (140) that receives the detection light (L2) reflected by an object and outputs a detection signal; a light projection adjustment unit (111) that recognizes a specific direction in which a detection result that indicates that the detection light (L1) is blocked is obtained as a designated direction among detection results based on the detection signals obtained by sequentially projecting the detection light (L1) in a plurality of predetermined specific directions by driving the optical axis adjustment element (130), and adjusts the projection direction of the detection light (L1) to be projected for inspection of an inspection object (290) based on the recognized designated direction; An optical sensor (100) comprising: [Explanation of symbols]

[0080] 100...optical sensor, 101...housing, 102...transmitting window, 103...cable, 110...control unit, 111...light projection adjustment unit, 112...distance calculation unit, 120...light projection element, 130...optical axis adjustment element, 140...light receiving element, 150...operation button, 160...display panel, 170...input / output IF, 180...storage unit, 210, 220, 230...spare work, 211, 231...inspection point, 290, 290a, 290b...inspection work, 291a, 291b...inspection point, 300...production line

Claims

1. a light-projecting element that projects detection light that is visible light; an optical axis adjustment element for adjusting an optical axis of the detection light projected from the light projecting element; a light receiving element that receives the detection light reflected by an object and outputs a detection signal; a light projection adjustment unit that recognizes a specific direction in which a detection result that indicates that the detection light is blocked is obtained as a designated direction among detection results based on the detection signals obtained by sequentially projecting the detection light in a plurality of predetermined specific directions by driving the optical axis adjustment element, and adjusts the projection direction of the detection light to be projected for inspecting the inspection object based on the recognized designated direction; An optical sensor comprising:

2. 2. The optical sensor according to claim 1, wherein the light projection adjustment unit sequentially projects light in the plurality of specific directions and the light projection direction set at that time as one cycle, and changes the manner of light projection between projecting light in the plurality of specific directions and projecting light in the light projection direction.

3. 3. The optical sensor according to claim 1, wherein each of the plurality of specific directions is set at an end of a range that can be adjusted by the optical axis adjustment element.

4. 4. The optical sensor according to claim 1, wherein, when a specific direction exists among the plurality of predetermined specific directions in which the reflected detection signal cannot be detected by the light receiving element, the light projection adjustment unit deflects the detection light to be projected in that specific direction to a direction in which the detection signal can be detected.

5. 5. The optical sensor according to claim 1, wherein the light projection adjustment unit deflects the detection light to be projected in each of the plurality of specific directions based on at least one of the plurality of predetermined specific directions or a distance to an object detected in the light projection direction.

6. The optical sensor according to claim 5 , wherein when the plurality of specific directions are directions inside a range that can be adjusted by the optical axis adjustment element, the light projection adjustment unit projects light toward an end direction to indicate the range.

7. 7. The optical sensor according to claim 1, wherein when a detection result is obtained in which the detection light for two or more specific directions out of the detection light projected in each of the plurality of specific directions is evaluated to have been successively blocked in succession, the light projection adjustment unit adjusts the light projection direction based on the order in which the two or more specific directions are blocked.

8. The optical sensor according to claim 7 , wherein the light projection adjustment unit stops adjusting the light projection direction for a preset time period when the light projection direction has been adjusted based on the order of interruption.

9. 9. The optical sensor according to claim 1, wherein the light projection adjustment unit determines the light projection direction when all of the detection results obtained by sequentially projecting light in the multiple specific directions are evaluated as indicating that the detection light is blocked.

10. 9. The optical sensor according to claim 1, wherein the light projection adjustment unit determines the light projection direction when a detection result obtained by sequentially projecting light in the multiple specific directions indicates that all of a preset combination of the detection lights are blocked.

11. 9. The optical sensor according to claim 1, wherein the light-projection adjustment unit projects the detection light as a confirmation light for receiving a confirmation instruction, and confirms the light-projection direction when a detection result indicates that the detection light of the confirmation light is obstructed.

12. the plurality of specific directions are set for a plurality of discrete points defined so as to cover at least a portion of a range that can be adjusted by the optical axis adjustment element, 2. The optical sensor according to claim 1, wherein the light projection adjustment unit recognizes a specific direction in which a detection result is obtained in which the detection light is evaluated to be most closely blocked as the indicated direction, and determines the light projection direction as the indicated direction.

13. A control method for an optical sensor including a light-projecting element that projects detection light, an optical axis adjustment element that adjusts an optical axis of the detection light projected from the light-projecting element, and a light-receiving element that receives the detection light reflected by an object and outputs a detection signal, comprising: a light projection step of sequentially projecting the detection light in a plurality of predetermined specific directions by driving the optical axis adjustment element; a recognition step of recognizing, as a pointing direction, a specific direction in which a detection result that indicates that the detection light is blocked has been obtained among detection results based on the detection signals obtained by projecting light in each of the plurality of specific directions in the light projection step; an adjustment step of adjusting a projection direction of the detection light to be projected for inspecting an inspection object based on the pointing direction recognized in the recognition step; A method for controlling an optical sensor comprising the steps of:

14. A control program for an optical sensor including a light-projecting element that projects detection light, an optical axis adjustment element that adjusts an optical axis of the detection light projected from the light-projecting element, and a light-receiving element that receives the detection light reflected by an object and outputs a detection signal, a light projection step of sequentially projecting the detection light in a plurality of predetermined specific directions by driving the optical axis adjustment element; a recognition step of recognizing, as a pointing direction, a specific direction in which a detection result that indicates that the detection light is blocked has been obtained among detection results based on the detection signals obtained by projecting light in each of the plurality of specific directions in the light projection step; an adjustment step of adjusting a projection direction of the detection light to be projected for inspecting an inspection object based on the pointing direction recognized in the recognition step; A control program for an optical sensor that causes a computer to execute the above.

Images