JP7602199B2 - Optical sensor, optical sensor control method, and optical sensor control program - Google Patents

Description

The present invention relates to an optical sensor, a control method for an optical sensor, and a control program for an optical sensor.

Optical sensors that detect the presence or absence of an object to be inspected and the distance to it 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.

JP 2017-53769 A

Optical sensors are installed on production lines and are sometimes used to measure the characteristic shapes of parts traveling along 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 close to the object being inspected. In recent years, wide-range optical sensors with detection ranges of several meters have therefore been developed. However, with wide-range optical sensors, even a slight angle error during installation will cause the detection light to deviate from the target location on the object being 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 are required to perform the cumbersome task of loosening and tightening the mounting fixture while checking the spot of the detection light.

The present invention has been made to solve these problems, and provides an optical sensor that does not require the troublesome task of adjusting the optical axis, even when detecting a relatively distant object.

The optical sensor in 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 is obtained in which the detection light is evaluated as being blocked 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. With the optical sensor configured in this way, the user can specify the projection direction of the detection light to be projected for the inspection of the inspection object simply by blocking the detection light in a specific direction with, for example, a fingertip, thereby eliminating the need to readjust the orientation of the optical sensor and improving operability.

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

In the optical sensor described above, each of the multiple specific directions may be set to the end of a range that can be adjusted by the optical axis adjustment element. By setting the specific directions to the end of the adjustable range in this manner, the user can easily recognize the range within which the detection light projected for inspecting the inspection object can be adjusted.

In the optical sensor described above, if there is a specific direction among a plurality of predetermined specific directions in which the light receiving element cannot detect the reflected detection signal, 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 way, 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 directional instructions.

In the optical sensor described above, the light projection adjustment unit may move the multiple specific directions based on at least one of multiple 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 light in the specific directions can be appropriately maintained regardless of the distance from the optical sensor, making it easier for the user to give directional instructions. In this case, if the multiple 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.

In the optical sensor described above, the light projection adjustment unit may adjust the projection direction of the detection light projected for inspecting the inspection object based on the order in which the two or more specific directions were blocked when a detection result is obtained that indicates that the detection light projected in each of a plurality of specific directions has been 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, it is preferable that the light projection adjustment unit suspends adjustment of the light projection direction for a preset time. Providing such a suspension period can prevent erroneous detection due to the reciprocating movement of the user's hand.

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 multiple specific directions are evaluated as detection results in which the detection light is blocked. In this way, by accepting a confirmation instruction consecutively to a direction instruction, the user does not need to operate the optical sensor to issue a confirmation instruction, which is expected to improve operability.

In the optical sensor described above, the light projection adjustment unit may confirm the light projection direction when a preset combination of detection light among the detection results obtained by sequentially projecting light in multiple specific directions is evaluated as being blocked. The light projection adjustment unit may also project detection light as a confirmation projection for receiving a confirmation instruction, and confirm the light projection direction when the detection result is evaluated as being blocked by the detection light of the confirmation projection. Even in this mode, the user does not need to operate the optical sensor to issue a confirmation instruction, and workability is expected to improve.

In the optical sensor described above, the multiple specific directions are set for multiple discrete points defined to cover at least a portion of the range that can be adjusted by the optical axis adjustment element, and the light projection adjustment unit may recognize the specific direction in which the detection result is evaluated as indicating that the detection light is most closely blocked as the indicated direction, and determine that light projection direction as the indicated direction. This indication method allows the light projection direction to be indicated more directly.

The 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 in which the detection light is sequentially projected in a plurality of predetermined specific directions by driving the optical axis adjustment element, a recognition step in which a specific direction in which a detection result is obtained in which the detection light is evaluated as being blocked is recognized as a pointed direction 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 in which the projection direction of the detection light to be projected for inspection of the inspection object is adjusted based on the pointed direction recognized in the recognition step.

In addition, the control program for the optical sensor in the 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 is evaluated as the detection light being 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 inspection object based on the pointed direction recognized in the recognition step.

In the second and third aspects, as in the first aspect, the direction of the detection light emitted to inspect the object to be inspected can be easily indicated, eliminating the need to readjust the orientation of the optical sensor and improving workability.

The present invention makes it possible to provide an optical sensor that does not require the need for complicated optical axis adjustment work, even when detecting a relatively distant object.

FIG. 2 is a perspective view of the appearance of an optical sensor. FIG. 1 is a system configuration diagram of an optical sensor. 11A and 11B are diagrams illustrating the projection of command light and adjustment light onto a preliminary workpiece. 13A and 13B are diagrams illustrating an adjustment method in which the adjustment light projection is moved to the right. 13A and 13B are diagrams illustrating an adjustment method in which the adjusted light projection is moved downward. 11A and 11B are diagrams illustrating a method for determining the projection direction of the adjusted light as the inspection direction. FIG. 1 is a diagram showing a state in which an inspection object is inspected. 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. 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. FIG. 13 is a diagram showing a state in which boundary light is cast in addition to designated light cast. 13A and 13B are diagrams illustrating another instruction method for moving the adjusted light projection. 13A and 13B are diagrams illustrating another method for determining the projection direction of the adjusted light as the inspection direction. 11A and 11B are diagrams illustrating an adjustment method for directly determining the inspection direction without projecting an adjustment light. FIG. 4 is a flowchart illustrating a processing procedure of a control unit.

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 problem.

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 undetected information indicating that the workpiece is not detected, and when the detection light _L2 can be received, it outputs distance information.

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 includes 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 aligned with any direction ( _xm , _yn ) indicated by dots within the deflectable range _R as shown in the figure.

Furthermore, the optical sensor 100 can detect distances in the range from _Dn to _Df along the projection direction of the detection light _L1 . That is, the range indicated by the dots in the figure is the detectable range V, and the optical sensor 100 outputs undetected information if no workpiece is 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.

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

Figure 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.

The light projecting element 120 is a laser diode that emits laser light in a wavelength band that is visible light (e.g., red light of 635 nm to 680 nm), and emits detection light _L1 modulated to a specific frequency (e.g., 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.

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.

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 electrical 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, it is not necessary 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.

The operation button 150 is an operation member that accepts specifications 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.

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, undetected 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 sending 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 also include a wireless connection unit compatible with a wireless LAN or Bluetooth (registered trademark).

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 instruct the start of inspection of a workpiece, the input/output IF 170 works in cooperation with the control unit 110 as a reception unit that receives the instruction to start inspection.

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, look-up 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 .

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 the specific direction in which the detection result that the detection light L _{1 is interrupted is obtained as the indicated direction among the detection results obtained by sequentially projecting the detection light L 1 in} a plurality of specific directions set in advance by driving the optical axis adjustment element 130, and adjusts the projection direction of the detection light L ₁ to be projected for the inspection of the inspection work based on the recognized indicated direction. In addition, when inspecting the inspection work, the optical axis adjustment element 130 is driven so that the detection light L ₁ 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 L ₁ and the received detection light L ₂ , 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, or, when the light receiving element 140 does not receive the detection light _L2 , can output specified non-detection information.

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.

3 is a diagram for explaining the projection of the instruction light projections _IU , _IR , _ID , and _IL and the adjustment light projection _LT to the preliminary work 210. The optical sensor 100 is fixed to a structure associated with the production line, facing the vicinity of the inspection position on the production line 300. The user places the preliminary work 210, which is a preliminary object of the same type as the object to be inspected, on the production line 300 so that the 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 work 210 on the production line 300 in an approximate location without paying much attention.

It is desirable that the preliminary workpiece 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 workpiece that is conveyed in sequence on the production line 300 is inspected to ensure that the hexagonal screws are properly fastened. In this case, the inspection point 211 is the head of the hexagonal screw, and it is desirable that the hexagonal screws are properly fastened in the preliminary workpiece 210 as well.

With the optical sensor 100 and the preliminary workpiece 210 thus 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, it sequentially and repeatedly executes the instruction light projections _IU , _IR , _ID , and _IL and the adjustment light projection L _T. The adjustment light projection L _T is light to be adjusted that is projected toward a tentative inspection direction to determine the projection direction (inspection direction) of the detection light _L1 that inspects the inspection target. At the start of the adjustment mode, the adjustment light projection L _T is directed toward the center of the deflectable range R, for example.

The instruction light projections _IU , _IR , _ID , and _IL are instruction detection lights projected toward the four directions of the deflectable range R in order to receive an instruction from the user to adjust the projection direction of the adjustment light projection L _T. In this embodiment, as shown in the figure, the instruction light projection _IU is projected toward the midpoint of the upper side of the boundary of the deflectable range R, the instruction light projection _IR is projected toward the midpoint of the right side of the boundary of the deflectable range R, the instruction light projection _ID is projected toward the midpoint of the lower side of the boundary of the deflectable range R, and the instruction light projection _IL is projected toward the midpoint of the left side of the boundary of the deflectable range R. That is, in this embodiment, four directions, namely, 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 the above.

The light projection adjustment unit 111 sequentially deflects the detection light L ₁ emitted from the light projection element 120, and repeats light projection in one cycle of command light projection I _U → command light projection _IR → command light projection _ID → command light projection _IL → adjustment light projection _LT . Specifically, the light projection is switched sequentially so that each light projection lasts, for example, for 0.01 seconds. Since the detection light L ₁ is visible light, the user can visually recognize the spots SP _U , SP _R , SP _D , SP _L , and SP _T formed by these light projections on the preliminary work 210. At the start of the adjustment mode, it is preferable to adjust the projection direction of the adjustment light L _T so that the spot SP _T is located inside the area surrounded by the spots SP _U , SP _R , SP _D , and SP _L , especially at the center of the surrounded area. When adjustments are made in this manner, the user can intuitively grasp the roles of the command light projections _IU , _IR , _ID , and _IL and the adjustment light projection L _T , and can easily grasp the deflection amount and deflection direction of the adjustment light L _T even if the spot SP _T is moved by subsequent adjustments.

Here, the light projection adjustment unit 111 differentiates the light projection _modes of the adjustment light _LT and the command light projections _IU , _IR , _ID , and _IL so that the spot SP _T of the adjustment light LT and the spots SP _U , _SPR , _SPD , and _SPL of the command light projections _IU , _IR , _ID , and _IL can be distinguished. Specifically, the light projection adjustment unit 111 cooperates with the control unit 110 to control the projection of the light projection element 120, and can increase the light emission intensity of the adjustment light _LT or blink it. By differentiating the light projection modes in this way, the user can easily recognize the role of each light projection, even though the detection light _L1 is projected from a single light projection element 120.

When the adjustment mode is started, the light-projection adjustment unit 111 causes the distance calculation unit 112 to calculate the distances for each of the command light projections I _U , _IR , _ID , and _IL executed at the start of the adjustment mode. The light-projection adjustment unit 111 stores these calculation results in the storage unit 180 as initial detection distances D _U , D _R , D _D , and D _L.

4 is a diagram for explaining an adjustment method in the case where the adjustment light L _T is moved to the right. When the adjustment mode is started as described above, the light projection adjustment unit 111 repeats the projection of the instruction light I _U →instruction light I _R →instruction light I _D →instruction light I _L →adjustment light L _T until the adjustment mode is ended. The distance calculation unit 112 calculates the detection distance for each of the instruction light projections I _U , I _R , I _D , and I _L in synchronization with the projection of each light. In this state, if the user sticks out his/her index finger in the optical path of the instruction light I _R as shown in the figure, for example, the spot S P _R is formed on the user's index finger, and the instruction light I _R is blocked by the index finger and does not proceed further back (indicated by a broken line). The distance calculation unit 112 calculates the distance D _R ' to the index finger for the instruction light I _R.

When the calculation result is handed over to the light projection adjustment unit 111, the light projection adjustment unit 111 evaluates that the instruction light projection I _R has been blocked by comparing it with the initial detection distance D _R. Since the instruction light projection I _R is projected to the right of the center of the deflectable range R, the light projection adjustment unit 111 deflects the adjusted light L _T by a preset deflection amount to the right from the light projection direction at that time based on the evaluation result. If the user holds out his/her index finger in the optical path of the instruction light projection I _R for a while, the adjusted light L _T is gradually deflected to the right and eventually reaches above the inspection point 211. The user waits for the right timing to move his/her index finger out of the optical path of the instruction light projection I _R.

Fig. 5 is a diagram for explaining an adjustment method in the case where the adjustment light L _T is moved downward. Following Fig. 4, when the user thrusts out his/her index finger into the optical path of the instruction light I _D as shown in the figure, the spot S P _D is formed on the user's index finger, and the distance calculation unit 112 calculates the distance D _D ' to the index finger for the instruction light I _D.

When the calculation result is handed over to the light projection adjustment unit 111, the light projection adjustment unit 111 evaluates that the instruction light projection I _D has been blocked by comparing it with the initial detection distance D _D. Since the instruction light projection I _D is projected downward with respect to the center of the deflectable range R, the light projection adjustment unit 111 deflects the adjusted light L _T downward from the light projection direction at that time by a preset deflection amount based on the evaluation result. If the user holds out his/her index finger in the optical path of the instruction light projection I _D for a while, the adjusted light L _T is gradually deflected downward and eventually reaches the inspection point 211. The user waits for the right timing to move his/her index finger out of the optical path of the instruction light projection I _D.

FIG. 6 is a diagram for explaining a method for determining the projection direction of the adjusted light L _T as the inspection direction. When the user causes the adjusted light L _T to reach the inspection point 211 as described above, the user determines the projection direction as the inspection direction. Specifically, for example, as shown in the figure, the user presses the determination button of the operation button 150 to determine the projection direction. When the projection direction of the adjusted light L _T at that time is determined as the inspection direction, the light projection adjustment unit 111 stores the direction coordinate (x _T , y _T ) indicating the inspection direction in the storage unit 180. The light projection adjustment unit 111 performs the determined inspection light L _C in a manner different from the projection manner of the adjusted light L _T for a certain period of time. Specifically, the light projection adjustment unit 111 cooperates with the control unit 110 to control the projection of the light projecting element 120, and can increase the emission intensity of the adjusted light L _T or make it blink. As a result, a highly visible spot SP _C is formed at the inspection point 211, and the user can confirm the location where the inspection is performed. Once the inspection direction is determined in this manner, the user can avoid the tedious task of repeatedly loosening and tightening the mounting fixture while checking the detection light spot, even when detecting an object that is relatively far away from the optical sensor 100.

7 is a diagram showing a state in which an inspection workpiece 290, which is an object to be inspected, is inspected. Once the inspection direction is determined as described above, the user removes the preliminary workpiece 210 and operates the production line 300 so that the target inspection workpiece 290 flows in sequence. Upon receiving an instruction to start inspection, the light projection adjustment unit 111 reads out the direction coordinates (x _T , y _T ) stored in the storage unit 180 and fixes the projection direction of the inspection light projection L _C to that direction. Each time the inspection workpiece 290 reaches a specified position on the production line 300, the control unit 110 performs the inspection light projection L _C to execute a detection process and outputs the detection result to an external device.

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, the hexagonal screw is properly fastened in a certain inspection work 290a, and the optical sensor 100 outputs the distance D _a to the external device as the detection distance at the inspection point 291a. The external device confirms that the distance D _a is within the allowable range and judges it as "pass". On the other hand, the hexagonal screw in the next inspection work 290b is insufficiently fastened and floats, and the optical sensor 100 outputs the distance D _b to the external device as the detection distance at the inspection point 291b. The external device confirms that the distance D _b is not within the allowable range and judges it as "fail". In this way, the optical sensor 100 can be used to judge whether the inspection work 290 is good or bad. The optical sensor 100 may also be configured to judge pass/fail and output the result to the external device.

Next, we will explain some modified examples. Figure 8 shows the first modified example, in which the direction of the instruction light is automatically adjusted according to the shape of the target object, the preliminary workpiece 220.

In the embodiment described with reference to Figures 3 to 6, the projection direction of the instruction light _IU , _IR , _ID , and _IL 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, and a spot cannot be formed. 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 the distance not being calculated. 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.

Therefore, the light projection adjustment unit 111 executes an adjustment to gradually move the projection direction of the instruction light that has resulted in the distance not being calculated toward the inside of the deflection possible range R. Specifically, for example, as shown in the figure, when the distance not being calculated is obtained for the initial instruction light projection _IU , the light projection adjustment unit 111 deflects the instruction light _IU downward by a preset deflection amount. In this case, the downward direction for the instruction light _IU is the center direction of the deflection possible range R. If the distance not being calculated is obtained again after the deflection, the instruction light _{IU is further deflected downward by a preset deflection amount. This process is repeated, and when a spot SP U is} formed on the preliminary work 210 and the distance detection is successful, the adjustment of the projection direction of the instruction light _IU is terminated.

When the spot SP _U is formed on the preliminary work 210 in this manner, the distance calculation unit 112 can calculate the initial detection distance D _U , and the user can recognize the optical path of the instruction light projection I _U. Similarly, for the instruction lights I _R , I _D , and I _L , if a result of distance calculation is not obtained, the light projection direction is gradually deflected toward the center of the deflection range R, thereby executing automatic adjustment.

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

Figure 9 shows a second modified example in which the direction of the instruction light is automatically adjusted depending on the distance to the target, the preliminary workpiece 210. As shown in Figure 1, the deflectable range R increases with distance from the optical sensor 100. Therefore, when the production line 300 is far from the optical sensor 100, the deflectable range R for the target increases, and setting the direction of the instruction light to the edge (boundary) of the deflectable range R often results in the distance not being calculated. Even if the distance can be calculated, the spacing between the spots formed by each increases, making it difficult for the user to block each light path.

Therefore, the light projection adjustment unit 111 adjusts the projection direction of each of the command light projections _IU , _IR , _ID , and _IL based on the distance to the preliminary workpiece 210 detected by at least one of the command light projections IU, IR, ID, and IL or the adjusted light projection _LT . For example, when the distance D _P is detected by the spot SP _T formed by the adjusted light projection _LT as shown in the figure, the command light projection frame S is determined according to a size that is predefined for the distance D _P , and the projection directions of each of the command light projections _IU , _IR , _ID , and _IL are adjusted to match the up, down, left, and right directions of this command light projection frame S.

By setting the instruction light projection frame S inside the deflectable range R in accordance with the distance to the preliminary workpiece 210 and adjusting the projection direction of the instruction light in this way, it is expected that the respective spots will be formed at appropriate intervals on the preliminary workpiece 210. This makes it easier for the user to perform the action of blocking each light path. Note that if there is an instruction light that results in an inability to calculate the distance even after adjusting the projection direction of the instruction light in this way, the example of Figure 8 may be applied to that instruction light, and the projection direction may be further adjusted.

Fig. 10 is a diagram showing a state in which boundary light projections _Pa , _Pb , _Pc , and _Pd are performed in addition to instruction light projections _IU , _IR , _ID , and _IL as a third modified example. If the instruction light projection frame S is set inside the deflectable range R according to the distance of the preliminary work 210 as in the example of Fig. 9, it becomes difficult for the user to recognize the range in which the adjustment light L _T can be moved. Therefore, the light projection adjustment unit 111 further executes instruction light boundary _{projections Pa} , _Pb , _Pc , and _Pd for indicating the adjustable range, in addition to the instruction light projections _IU , _IR , _ID , and _IL for receiving a movement instruction for the adjustment light L T.

As shown in the figure, if the preliminary work 230 is relatively large, the boundary projections P _a , P _b , P _c , and P _d projected onto the four corners of the deflection possible range R can form spots SP _a , SP _b , SP _c , and SP _d , respectively, on the surface of the preliminary work 230. By visually checking the spots SP _a , SP _b , SP _c , and SP _d thus formed, the user can recognize the range within which the adjustment projection L _T can be moved.

The light-projection adjustment unit 111 sequentially deflects the detection light _L1 emitted from the light-projecting element 120, and repeats light projection in the following cycle: command light projection _IU → command light projection _IR → command light projection _ID → command light projection _IL → adjustment light projection _LT → boundary light projection P _a → boundary light projection P _b → boundary light projection P _c → boundary light projection P _d . Alternatively, the frequency of the boundary light projection may be reduced, for example, by reducing the frequency of the boundary light projection to half the frequency of the command light projection. Furthermore, the emission intensity of the boundary light projection may be reduced or the lighting time may be shortened, relative to the command light projection.

By performing boundary projection in this manner, the user can easily perform adjustments, particularly when moving the adjustment projection L _T beyond the designated projection frame S. For example, as shown in the figure, this is convenient when moving the adjustment projection L _T to an inspection point 231 that exists outside the designated projection frame S.

Fig. 11 is a diagram for explaining another instruction method for moving the adjustment light projection L _T as a fourth modified example. 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 successively blocked, and the direction instruction is recognized based on the order in which they are blocked. Fig. 11 (A) to Fig. 11 (C) are diagrams showing how one of the instruction lights is blocked in order over time.

Specifically, the user shakes his palm from top to bottom, and Fig. 11(A) shows the state where the command light projection _IU is blocked in the initial stage. After that, as shown in Fig. 11(B), the palm blocks the command light projections I _R and I _L in addition to the command light projection _IU , and eventually, as shown in Fig. 11(C), the palm blocks the command light projection I _D. Fig. 11(C) shows the state where I _R is also blocked at the same time. When the light projection adjustment unit 111 receives a calculation result from the distance calculation unit 112 that can be evaluated as indicating such sequential blocking over time, it recognizes that the palm has been shaken from top to bottom, and deflects the adjusted light projection L _T downward from the light projection direction at that time by a preset deflection amount. Similarly, when it is recognized that the palm of the hand is shaken from bottom to top, the adjustment light L _T is deflected upward, when it is recognized that the palm is shaken from right to left, the adjustment light L _T is deflected to the left, and when it is recognized that the palm is shaken from left to right, the adjustment light L _T is deflected to the right by a preset deflection amount.

For example, if a user tries to wave his/her palm from top to bottom repeatedly, the palm will also be waved from bottom to top repeatedly, so in order to avoid erroneous recognition, the light projection adjustment unit 111 stops recognizing the pointing direction for a preset time period (e.g., one second) once it has recognized the pointing direction. After the user waves their palm once to have the pointing direction recognized, they return their palm to the initial position while recognition of the pointing direction is stopped.

12 is a diagram illustrating another method for determining the projection direction of the adjustment light L _T as the inspection direction as a fifth modified example. This modified example is compatible with the fourth modified example, but is not limited to this and can be combined with any of the previous embodiments.

6, when the adjusted light projection L _T reaches the inspection point 211, the user operates the operation button 150 to confirm the light projection direction as the inspection direction. In this modified example, after the adjusted light projection L _T reaches the inspection point 211, the user simultaneously blocks all of the instruction light projections I _U , _IR , _ID , and _IL as shown in the figure, thereby confirming the light projection direction as the inspection direction.

When the light projection adjustment unit 111 receives from the distance calculation unit 112 a calculation result that indicates that all of the instruction light projections _IU , _IR , _ID , and _IL are blocked, it determines the projection direction of the adjustment light L _T at that time as the inspection direction. That is, the direction coordinates ( _xT , _yT ) indicating the inspection direction are stored in the storage unit 180. If the determination instruction is accepted consecutively to the direction instruction in this way, the user does not need to operate the operation button 150 of the optical sensor 100 to give the determination instruction, and this is expected to improve operability.

The method of detecting the final instruction is not limited to the method of detecting that all of the instruction light projections _IU , _IR , _ID , and _IL are blocked at the same time, and various other methods may be adopted. For example, when it is detected that all of the instruction light projections of a preset combination of the instruction light projections _IU , _IR , _ID , and _IL are blocked, the projection direction of the adjustment light projection L _T at that time may be determined as the inspection direction. For example, in the combination of the instruction light projections _IU and _ID , it is considered that simultaneous blocking rarely occurs accidentally, so that when the instruction light projections of such a combination are blocked at the same time, it may be recognized as a final instruction. In addition to the instruction light projection, a final light projection for receiving a final instruction may be performed. When the final light projection is blocked, the projection direction of the adjustment light projection L _T at that time is determined as the inspection direction. The final light projection may be performed in a direction away from the projection direction of the instruction light.

13 is a diagram explaining an adjustment method for directly determining the inspection direction without projecting the adjustment light L _T as a sixth modified example. In all of the embodiments described so far, the instruction light I _U , I _R , I _D , and I _L are projected in four directions (or more) to receive an instruction to move the adjustment light L _T , and when any of them is blocked, the light is deflected in that direction stepwise. In this modified example, the projection direction of the instruction light I _M is set for each of the lattice points defined in the deflectable range R. Then, the light projection adjustment unit 111 recognizes the projection direction of the instruction light I _M for which a detection result is obtained that is evaluated as being most closely blocked as the instruction direction, and immediately determines the instruction direction as the inspection direction.

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 deflection possible range R. Each light projection onto the lattice point is designated as an instruction light projection I M. For example, when a user wants to direct the head of a hexagonal screw, which is the inspection point 211, in the inspection direction, the user thrusts out his/her index finger so as to block one of the instruction _{lights I M irradiating} the screw head at a location closest to the optical sensor 100 compared to the other instruction lights I _M. Then, the light projection adjustment unit 111 recognizes the instruction light projection I _M as the instruction direction and determines it as the inspection direction for inspecting the inspection object.

13B shows a state in which the confirmed inspection light projection L _C is performed for a certain period of time in a mode different from the mode of projection of the instruction light I _M. Specifically, the light projection of the light-projecting element 120 can be controlled in cooperation with the control unit 110 to increase the emission intensity of the adjusted light L _T or to make it blink. According to such an adjustment method, it is possible to omit the work of correcting the projection direction of the adjusted light L _T through multiple instruction steps, and therefore it is possible to confirm the inspection direction more directly and in a short time.

In the illustrated example, the projection direction of the command light I _M is set for each of the lattice points defined in the deflectable range R, but the setting of the projection direction of the command light I _M is not limited to this. The projection direction of the command light I _M may be set for each of a plurality of discrete points defined so as to cover at least a part of the deflectable range R.

Next, the processing procedure of the control unit 110 will be described using the embodiment described using Figures 3 to 7 as a representative example. Figure 14 is a flow diagram explaining the processing procedure of the control unit 110. The flow starts when the adjustment mode is selected with the optical sensor 100 fixed to a structure associated with the production line 300 and the preliminary workpiece 210 placed on the production line 300.

In step S101, the light projection adjustment unit 111 sequentially projects a command light I _U toward the upper boundary of the deflection range R, a command light I _R toward the right boundary, a command light I _D toward the lower boundary, and a command light I _L toward the left boundary, and causes the distance calculation unit 112 to calculate the distance for each light. The light projection adjustment unit 111 stores the results of these calculations in the storage unit 180 as initial detection distances D _U , D _R , D _D , and D _L.

Next, the process proceeds to step S102, where the light-projection adjustment unit 111 executes command light projection I _U → command light projection _IR → command light projection _ID → command light projection _IL in that order. Then, in step S103, it is determined whether any of the command light projections has been blocked. Specifically, it is determined whether a light projection has been blocked by determining whether the detection distances D _U ', D _R ', D _D ', and D _L ' calculated for each light projection have become shorter than the initial detection distances D _U , D _R , D _D , and D _L by exceeding a threshold value.

If it is determined that none of the light projections are blocked, the process proceeds to step S104, where the light projection adjustment unit 111 projects the adjusted light L _T in the same direction as the previous time, and then proceeds to step S106. If it is determined that any of the light projections is blocked, the light projection adjustment unit 111 updates the direction of the adjusted light L _T to the direction indicated by the blocked instruction light, and then proceeds to step S106.

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 light projection adjustment unit 111 returns to step S102 and continues the adjustment mode. If a confirmation instruction has been received, the projection direction of the adjusted light L _T at that time is confirmed as the inspection direction, the direction coordinates (x _T , y _T ) indicating the inspection direction are stored in the storage unit 180, the adjustment mode is terminated, and the process proceeds to step S107.

When the control unit 110 receives an instruction to start inspection in step S107, it reads out the direction coordinates ( _xT , _yT ) stored in the memory unit 180 and fixes the projection direction of the inspection light L _C to that direction. Then, the process proceeds to step S108, where the inspection light L _C is projected every time the inspected workpiece 290 reaches a specified position on the production line 300, causing a detection process to be executed and the detection results to be output to an external device. When the inspection of the planned number of works flowing on the production line 300 has been completed, the series of processes ends.

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 depending on 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.

[Additional Notes]
A light-projecting element (120) that projects a detection light (L ₁ ) which is visible light;
an optical axis adjustment element (130) for adjusting the optical axis of the detection light (L ₁ ) 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;
The optical sensor (100) is provided with a light projection adjustment unit (111) which recognizes as an indicated direction a specific direction in which a detection result is obtained in which the detection light ( _L1 ) is evaluated as being blocked, among detection results based on the detection signals obtained by driving the optical axis adjustment element (130) to sequentially project the detection light ( _L1 ) in a plurality of predetermined specific directions, and adjusts the projection direction of the detection light ( _L1 ) to be projected for inspection of an inspection object (290) based on the recognized indicated direction.

100...Optical sensor, 101...Housing, 102...Transmission 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...Memory unit, 210, 220, 230...Preliminary work, 211, 231...Inspection location, 290, 290a, 290b...Inspection work, 291a, 291b...Inspection location, 300...Production line

Claims (14)

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;
an optical sensor including: a light projection adjustment unit that recognizes, 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 the detection signals obtained by driving the optical axis adjustment element to sequentially project the detection light in a plurality of predetermined specific directions; and adjusts the projection direction of the detection light to be projected for inspecting an inspection object based on the recognized pointed direction. The optical sensor according to claim 1, wherein the light projection adjustment unit sequentially projects light in the multiple specific directions and the currently set light projection direction as one cycle, and the manner of light projection is different when projecting light in the multiple specific directions and when projecting light in the light projection direction. The optical sensor according to claim 1 or 2, wherein each of the plurality of specific directions is set at the end of a range that can be adjusted by the optical axis adjustment element. The optical sensor according to any one of claims 1 to 3, wherein, if there is a specific direction among the plurality of specific directions set in advance in which the reflected detection signal cannot be detected by the light receiving element, the light projection adjustment unit deflects the detection light projected in that specific direction to a direction in which the detection signal can be detected. The optical sensor according to any one of claims 1 to 4, wherein the light projection adjustment unit deflects the detection light projected in each of the plurality of specific directions based on at least one of the plurality of predetermined specific directions or the distance to the object detected in the light projection direction. The optical sensor according to claim 5, wherein the light projection adjustment unit projects light toward the end to indicate the range when the plurality of specific directions are inside the range that can be adjusted by the optical axis adjustment element. The optical sensor according to any one of claims 1 to 6, wherein, when a detection result is obtained in which the detection light is evaluated to have been successively blocked in two or more specific directions among the detection light projected in each of the plurality of specific directions, the light projection adjustment unit adjusts the light projection direction based on the order in which the two or more specific directions are blocked. 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 is adjusted based on the order of interruptions. The optical sensor according to any one of claims 1 to 8, 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. The optical sensor according to any one of claims 1 to 8, 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 the detection lights of a preset combination are blocked. The optical sensor according to any one of claims 1 to 8, wherein the light projection adjustment unit projects the detection light as a confirmation projection for receiving a confirmation instruction, and when the detection result indicates that the detection light of the confirmation projection is obstructed, the optical sensor confirms the light projection direction. 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. 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;
and an adjustment step of adjusting a projection direction of the detection light projected for inspecting an inspection object based on the pointing direction recognized in the recognition step. 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;
and an adjustment step of adjusting the projection direction of the detection light projected for inspecting the object to be inspected, based on the pointing direction recognized in the recognition step.

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