JP7619100B2 - 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.

Conventionally, optical sensors that measure the distance to an object are known. Patent Document 1 discloses a technology in which an optical sensor forms a linear light spot and receives reflected light from this linear light spot with a two-dimensional image sensor, thereby detecting the distance to each of multiple points on the object using a triangulation method.

JP 2020-180918 A

In the technology for detecting the distance at multiple points on an object using the above-mentioned triangulation method, if one wishes to increase the distance between the optical sensor and the object (hereinafter also referred to as the "detection distance") while maintaining accuracy, it is necessary to increase the size of the sensor.

In order to solve the above problems, the present invention aims to provide an optical sensor, an optical sensor control method, and an optical sensor control program that can accurately detect detection distances at multiple points on an object while preventing the sensor size from increasing, regardless of the length of the detection distance.

An optical sensor according to one aspect of the present invention includes a light-projecting element that projects detection light, an adjustment unit that adjusts the optical axis of the detection light projected from the light-projecting element so that it forms an angle with respect to a reference axis, a light-receiving element that receives the detection light reflected from an object and outputs a detection signal, and a distance calculation unit that calculates the distance between each of the multiple positions and the optical sensor in the direction of the reference axis by a ToF method based on the detection signal obtained by driving the adjustment unit to project the detection light to each of multiple positions on the object.

According to this aspect, the optical sensor can adjust the optical axis to project light onto multiple positions on the object. Therefore, according to this aspect, the optical sensor can detect the detection distance at multiple points on the object with one sensing mechanism, without using multiple sensing mechanisms or forming a linear light spot and receiving it with a two-dimensional image sensor. By using the ToF method, even if the detection distance becomes long, the size of the sensor can be suppressed from increasing, and the risk of accuracy decreasing compared to the triangulation method can be reduced. Therefore, according to this aspect, the optical sensor can accurately detect the detection distance at multiple points on the object, regardless of the length of the detection distance, while suppressing the size of the sensor from increasing.

In the above aspect, the optical sensor may further include a displacement amount calculation unit that calculates the amount of displacement between a first position and a second position among the multiple positions, the amount of displacement being parallel to the direction of the reference axis, based on the distance between each of the multiple positions.

According to this aspect, the optical sensor can calculate the amount of displacement between two points included in the multiple positions based on the detection distances of each of the multiple positions calculated by the ToF method. Therefore, according to this aspect, the optical sensor can accurately detect the displacement between multiple points while preventing the sensor size from increasing, regardless of the length of the detection distance.

In the above aspect, the optical sensor may further include a tilt calculation unit that calculates the tilt of the object between the first position and the second position based on the amount of displacement.

According to this aspect, the optical sensor can calculate the inclination of the object between multiple points based on the amount of displacement in the reference axis direction between the multiple points. Therefore, according to this aspect, the optical sensor can accurately detect the inclination of the object between multiple points while preventing the sensor size from increasing, regardless of the length of the detection distance.

In the above aspect, the optical sensor further includes a switching unit that switches between operation modes of the optical sensor including a first mode and a second mode, the adjustment unit adjusts the optical axis to project light in a specific direction in the first mode and adjusts the optical axis to project light in multiple directions in the second mode, and the distance calculation unit calculates the distance between a single position on the object and the optical sensor based on a detection signal obtained by projecting the detection light in the first mode, and calculates the distance between each of multiple positions on the object and the optical sensor based on the detection signals obtained by projecting the detection light in the second mode.

According to this aspect, the optical sensor can switch between calculating the distance to a single reflection position and calculating the distance to multiple reflection positions for each different operation mode. Therefore, according to this aspect, the optical sensor can switch to the first mode when it is desired to detect the distance to a single point on an object like a conventional ToF sensor, and can switch to the second mode when it is desired to detect the distance to multiple points on an object and calculate the amount of displacement or tilt between multiple points, depending on the application.

In the above aspect, the adjustment unit may include an optical axis adjustment element that is housed in the housing together with at least the light-emitting element and the light-receiving element and adjusts the optical axis of the detection light emitted from the light-emitting element.

According to this aspect, the optical sensor does not need to have a movable part outside the housing to adjust the optical axis of the detection light L1. Therefore, according to this aspect, the optical sensor can be easily installed because the housing can be directly fixed to, for example, a structure associated with the production line, and it is also less susceptible to the effects of inadvertent contact by workers.

In the above embodiment, the optical axis adjustment element may include a liquid crystal device that adjusts the optical axis of the detection light by deflecting the detection light.

According to this aspect, the optical sensor can adjust the optical axis to project light onto multiple, mutually-distant positions by using the above-mentioned liquid crystal device as an optical axis adjustment element. In addition, forming a linear light spot to detect the distance to multiple positions on the target object as in Patent Document 1 tends to reduce the power density of the detection light, but according to this aspect, the optical sensor can project detection light with higher density onto any multiple positions.

In the above aspect, the optical sensor may further include a memory unit that stores one or more angles with respect to the reference axis, and the adjustment unit may adjust the optical axis of the detection light based on the one or more angles stored in the memory unit.

According to this aspect, the optical sensor adjusts the optical axis by referring to its own memory unit, allowing for faster processing compared to receiving and sending angle information from an external device.

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 adjustment unit that adjusts the optical axis of the detection light projected from the light-projecting element so that it forms an angle with a reference axis, and a light-receiving element that receives the detection light reflected by an object and outputs a detection signal, and includes a distance calculation step of calculating the distance between each of the multiple positions and the optical sensor by a ToF method based on the detection signal obtained by driving the adjustment unit to project the detection light to each of multiple positions on the object.

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 adjustment unit that adjusts the optical axis of the detection light projected from the light-projecting element so that it forms an angle with a reference axis, 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 distance calculation step of calculating the distance between each of the multiple positions and the optical sensor by a ToF method based on the detection signal obtained by projecting the detection light to each of multiple positions on the object by driving the adjustment unit.

In the second and third aspects, as in the first aspect, the detection distance at multiple points on the target object can be detected with high accuracy regardless of the length of the detection distance.

The present invention provides an optical sensor, an optical sensor control method, and an optical sensor control program that can accurately detect detection distances at multiple points on an object while preventing the sensor size from increasing, regardless of the length of the detection distance.

1 is a perspective view of an external appearance of an optical sensor according to an embodiment; FIG. 1 is a system configuration diagram of an embodiment. 10A and 10B are diagrams for explaining an example of calculation of a displacement amount of an object according to an embodiment. 10A and 10B are diagrams for explaining an example of calculation of the inclination of an object according to an embodiment. 5A to 5C are diagrams for explaining an example of distance detection to an object in each of a first mode and a second mode of the optical sensor according to the embodiment. FIG. 4 is a flow chart showing an example of an operation of the optical sensor according to the embodiment.

A preferred embodiment of the present invention (hereinafter referred to as "this embodiment") will be described with reference to the attached drawings. Note that in each drawing, parts with the same reference numerals have the same or similar configurations.

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 an object, the distance to a specific point, etc., and is installed and used, for example, on a production line in a factory. The optical sensor 100 projects a detection light _L1 toward the object and receives a detection light _L2 that is reflected by the object and returns. The optical sensor 100 uses a ToF method that detects distance information by measuring the round-trip time of the detection light. When the optical sensor 100 cannot receive the detection light _L2 , it outputs undetected information indicating that the object is not detected, and when the optical sensor 100 can receive the detection light _L2 , 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 as shown in the figure.

In other words, when the optical axis of the detection light _L1 when not deflected by the optical axis adjustment element is used as a reference, the optical sensor 100 can adjust the optical axis so that it forms an angle with the reference optical axis (hereinafter also referred to as the "reference axis"). As a result of this adjustment, the optical sensor 100 can project the detection light L1 to a plurality of positions that are mutually separated within the deflection possible range. Then, the optical sensor 100 can selectively receive the detection light L2 that is reflected and returned from the specified reflection position by specifying one or more reflection positions (hereinafter also referred to as the "reflection position") from the plurality of positions. In this embodiment, an example will be described in which an adjustment unit provided in the housing 101 adjusts the optical axis of the detection light, but the adjustment unit is not limited to this. Also, in this embodiment, an example will be described in which the optical axis of the detection light _L1 when not deflected is used as the reference axis, but the reference axis is not limited to this.

The optical sensor 100 can detect distances (hereinafter also referred to as "detection 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, and the optical sensor 100 outputs undetected information if no object is present within this range, and outputs distance information to the reflection position of the detection light L1 if an object 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. In addition, a display panel 160 is provided on one side of the housing 101, and the display panel 160 displays one or more angles relative to a set reference axis (hereinafter, the angle relative to the reference axis is also simply referred to as "angle"), or the range in which this angle can take (hereinafter, also referred to as "angle range"). The cable 103 is connected to an external device such as a PLC or PC, and transmits an output signal 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 FIG. 1 are also shown to indicate the orientation of the components represented 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 target object.

The light projecting element 120 is an element that projects the detection light _L1 . The light projecting element 120 is a laser diode that emits laser light (e.g., red light of 635 nm to 680 nm), and emits the detection light _L1 modulated to a specific frequency (e.g., 12 MHz) under the control of the control unit 110. If the wavelength band of the detection light _L1 is in the visible band, the spot irradiated on the object can be visually recognized, which is convenient when adjusting the detection light _L1 to a desired direction or when checking the inspection location where the inspection is being performed. 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. The optical axis adjustment element 130 is an example of an adjustment unit, and adjusts the optical axis of the detection light _L1 projected from the light projecting element 120 so that it forms an angle with respect to the reference axis. With this configuration, it is possible to detect detection distances at multiple points on an object with one sensing mechanism, without using multiple sensing mechanisms or forming a linear light spot and receiving it with a two-dimensional image sensor.

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 described later. With this configuration, the optical axis adjustment element 130 does not need to have a movable part for adjusting the optical axis of the detection light _L1 outside the housing 101. For this reason, with this configuration, the housing 101 can be directly fixed to, for example, a structure associated with the production line, making it easy to install the optical sensor 100 and less susceptible to the effects of inadvertent contact by an operator.

The optical axis adjustment element 130 may include, for example, a liquid crystal device that adjusts the optical axis of the detection light _L1 by deflecting the detection light _L1 . The liquid crystal device achieves deflection by, for example, applying a voltage to a liquid crystal cell to control the on/off state. 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.

According to the above configuration, the optical axis adjustment element 130 can be adjusted to project light onto multiple, mutually-distant positions by using the above-mentioned liquid crystal device. In addition, forming a linear light spot to detect the distance to multiple positions on the target object, as in Patent Document 1, tends to reduce the power density of the detection light, but with the above configuration, it is possible to project detection light of higher density onto any multiple positions. In addition, with the above configuration, the optical axis adjustment element 130 can be realized with a simpler configuration than a MEMS mirror or the like that requires a movable part.

The optical axis adjustment element 130 may, for example, adjust the optical axis to project light in a specific direction in the first mode, and adjust the optical axis to project light in multiple directions in the second mode. Here, the "first mode" and "second mode" are operating modes of the optical sensor 100. Furthermore, this "specific direction" is typically a direction in which the reference axis and the optical axis coincide, but is not limited to this.

The optical axis adjustment element 130 may adjust the optical axis of the detection light _L1 based on, for example, one or more angles stored in a storage unit 180, which will be described later.

With the above configuration, the optical axis adjustment element 130 adjusts the optical axis by referring to the memory unit 180 housed in the housing 101, allowing for faster processing compared to receiving and sending angle information from an external device.

The light receiving element 140 is an element capable of photoelectric conversion, and receives the detection light _L2 reflected by the object and outputs a detection signal. The light receiving element 140 may be, for example, a photodiode (PDA) or a position sensitive detector (PSD). As another example, the light receiving element 140 may be, for example, a CMOS sensor having photoelectric conversion pixels arranged in a two-dimensional shape. The light receiving element 140 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 object and the detection light _L2 received by the light receiving element 140 are shown separately, but in reality, they are the same optical path as shown in FIG. 1, and the detection light L1 and the detection light _L2 are separated using, for example, a dichroic mirror.

The operation button 150 is an operation member that accepts a designation from a user, and may include, for example, an UP button, a DOWN button, a cross button, and the like. The operation button 150, in cooperation with the control unit 110, functions as a reception unit that accepts in advance the designation of a specific angle with respect to the reference axis from the range of angles with respect to the reference axis of the detection light L1 that the optical axis adjustment element 130 can adjust. The operation button 150 may also, for example, cooperate with the control unit 110 and function as a reception unit that accepts the designation of the operation mode of the optical sensor 100. Details of the operation mode will be described later. In addition to these functions as a reception unit, the operation button 150 also functions 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 other devices such as a touch sensor may be used.

The display panel 160 is, for example, a liquid crystal panel, and displays the setting state of the optical sensor 100, detection information as a detection result, non-detection information, etc. Note that 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. Note that the input/output IF 170 is not limited to a wired connection via the cable 103, and may include a connection unit corresponding to a wireless LAN or Bluetooth (registered trademark). Here, the "detection information" is information indicating the detection distance or displacement detected by the optical sensor 100, and includes at least either the distance information described above or the displacement information described below.

The storage unit 180 is a non-volatile storage medium, and is composed of, for example, a flash memory. In addition to programs that control and process the optical sensor 100, the storage unit 180 can store various parameter values, functions, lookup tables, etc. used for control and calculation.

The storage unit 180 may store, for example, one or more angles or angle ranges relative to a reference axis. The storage unit 180 may store, for example, one or more angles or angle ranges received by the reception unit.

The control unit 110 also functions 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, a distance calculation unit 112, and a displacement amount calculation unit 113.

The light projection adjustment unit 111 drives the optical axis adjustment element 130 so as to project the detection light _L1 forming an angle with the reference axis, and causes the light projection element 120 and the light receiving element 140 to execute detection processing. The light projection adjustment unit 111 may, for example, refer to a storage unit 180 that stores one or more angles formed with the reference axis, and drive the optical axis adjustment element 130 so as to form the one or more angles with the reference axis.

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 a detection distance to the object. The distance calculation unit 112 calculates the detection distance between each of the multiple reflection positions on the object and the optical sensor 100 using the ToF method based on a detection signal obtained by driving the optical axis adjustment element 130 to project the detection light _L1 to each of the multiple positions on the object. The control unit 110 puts the calculation result of the distance calculation unit 112 into a data structure and outputs it as distance information. Alternatively, when the light receiving element 140 does not receive the detection light L2, it outputs specified non-detection information.

For example, in the first mode, the distance calculation unit 112 may calculate the distance between a single reflection position on the object and the optical sensor 100 based on a detection signal obtained by projecting the detection light _L1 . Also, in the second mode, the distance calculation unit 112 calculates the distance between each of a plurality of reflection positions on the object and the optical sensor 100 based on a detection signal obtained by projecting the detection light _L1 .

According to the above configuration, the distance calculation unit 112 can switch between calculating the distance to a single reflection position or calculating the distance to multiple reflection positions for each different operation mode. Therefore, according to the above configuration, depending on the application of the optical sensor 100, for example, when it is desired to detect the distance to a single point on an object like a conventional ToF sensor, it can switch to the first mode, and when it is desired to detect the distance to multiple points on an object and calculate the amount of displacement or tilt between multiple points, it can switch to the second mode.

The displacement amount calculation unit 113 compares the detection distances at each of the multiple reflection positions to calculate the amount of displacement (hereinafter also simply referred to as "displacement amount") in a direction parallel to the direction of the reference axis between a first position and a second position among the multiple positions. The second position is a position among the multiple positions that is different from the first position. The displacement amount calculation unit 113 outputs displacement information indicating the calculated amount of displacement.

Here, an example of the calculation of the displacement amount in the displacement amount calculation unit 113 will be described with reference to FIG. 3. As shown in FIG. 3, the optical sensor 100 projects the detection light _L1 and calculates the detection distances to the reflection positions (indicated as "spot type" in FIG. 3) of three points (reference position, point a, and point b). In this example, the optical axis of the detection light _L1 projected to this reference position is the reference axis. In this example, the direction parallel to the reference axis is the Z axis direction, and the direction perpendicular to the reference axis is the X axis direction. When projecting light to points a and b, the optical sensor 100 adjusts the optical axis so as to form an angle with this reference axis. In this example, the first position is point a, and the second position is point b. In this example, the value of the detection distance along the optical axis of the detection light is called the "distance value", and the value of the distance between the optical sensor 100 in the Z axis direction and each of the reflection positions calculated based on the distance value is called the "Z axis distance value (D _Z )". In this example, the angle that light makes with respect to the reference axis when it is projected onto each reflection position other than the reference position is called the "angular displacement amount (θ ₁ )" (in Figs. 3 and 4, this is indicated as the "tilt angle (θ ₁ )").

When the reference position is the reflection position, the displacement amount calculation unit 113 calculates a relative value of 0 for the distance value of 2500 mm calculated by the distance calculation unit 112. When point a is the reflection position, the distance calculation unit 112 calculates a Z-axis distance value of 2468.5 mm based on the calculated distance value of 2470 mm and the angular displacement amount of 2°. Then, the displacement amount calculation unit 113 compares this Z-axis distance value with the distance value of the reference position, and calculates a relative value of -31.5 mm as a result of the comparison. The displacement amount calculation unit 113 calculates a relative value of -30. When point b is the reflection position, the distance calculation unit 112 calculates a Z-axis distance value of 2488.5 mm based on the calculated distance value of 2490 mm and the angular displacement amount of 2°. Then, the displacement amount calculation unit 113 compares this Z-axis distance value with the distance value of the reference position, and calculates a relative value of -11.5 mm as a result of the comparison. The displacement amount calculation unit 113 calculates the amount of displacement in the Z-axis direction between two points on the object based on these calculated relative values. For example, the displacement amount calculation unit 113 may calculate the amount of displacement in the Z-axis direction between points a and b to be 20 mm based on the respective relative values (-31.5 mm and -11.5 mm).

According to the above configuration, the displacement amount calculation unit 113 can calculate the amount of displacement between two points included in the multiple positions based on the detection distances of each of the multiple positions calculated by the ToF method. By using the ToF method, even if the detection distance is long, the size of the sensor is not increased, and the risk of accuracy decreasing compared to the triangulation method can be reduced, and the risk of detection failure can also be reduced. Therefore, according to the above configuration, regardless of the length of the detection distance, the detection distances at multiple points on the target object can be accurately detected while suppressing the increase in size of the sensor, and the displacement between multiple points can be accurately calculated.

The tilt calculation unit 114 calculates the tilt of the object between the first position and the second position among the multiple positions based on the amount of displacement calculated by the displacement calculation unit 113.

Here, an example of the calculation of the inclination in the inclination calculation unit 114 will be described with reference to Fig. 4. In this example, similar to the example in Fig. 3, the optical sensor 100 projects the detection light _L1 and calculates the detection distances from the reflection positions of three points (the reference position, point a, and point b).

As in the example of FIG. 3, when the reference position is the reflection position, the displacement amount calculation unit 113 calculates a relative value of 0 for the distance value of 2500 mm calculated by the distance calculation unit 112. When point a is the reflection position, the distance calculation unit 112 calculates a Z-axis distance value of 2488.5 mm based on the calculated distance value of 2490 mm and the angular displacement amount of 2°. Then, the displacement amount calculation unit 113 compares this Z-axis distance value with the distance value of the reference position, and calculates a relative value of -11.5 mm as a result of the comparison. Also, when point b is the reflection position, the distance calculation unit 112 calculates a Z-axis distance value of 2508.5 mm based on the calculated distance value of 2510 mm and the angular displacement amount of 2°. Then, the displacement amount calculation unit 113 compares this Z-axis distance value with the distance value of the reference position, and calculates a relative value of +8.5 mm as a result of the comparison. The displacement calculation unit 113 calculates the displacement in the Z-axis direction between points a and b to be 20 mm based on their relative values (-11.5 and +8.5).

The tilt calculation unit 114 calculates the angle θ2 as the tilt of the object between points a and b based on the calculated displacement amount and the displacement amount in the X-axis direction between points a and b (in FIG. 4, this is indicated as "spot movement amount"). The tilt calculation unit 114 may calculate the angle _θ2 by, for example, calculating tan _θ2 (the displacement amount in the Z- _axis direction between points a and b/the displacement amount in the X-axis direction between points a and b).

According to the above configuration, the tilt calculation unit 114 can calculate the tilt of the object between points a and b based on the amount of displacement in the Z-axis direction between points a and b. Therefore, according to the above configuration, the tilt calculation unit 114 can accurately detect the tilt of the object between multiple points regardless of the length of the detection distance.

The switching unit 115 switches between the operation modes of the optical sensor, including the first mode and the second mode. For example, the switching unit 115 may switch between the first mode and the second mode based on the designation of the operation mode received by the reception unit. As another example, the switching unit 115 may switch between the first mode and the second mode based on designation information provided from an external device via the input/output IF 170. This designation information is information indicating the designation of the operation mode. In this embodiment, the mode in which the detection light reflected from a single reflection position is detected (hereinafter referred to as the "single-point mode") is the first mode, and the mode in which the detection light _L2 reflected from each of the multiple reflection positions is detected (hereinafter referred to as the "multi-point mode") is the second mode. In the single-point mode, the optical sensor 100 projects light at a specific position on the object and detects the distance between this specific position and the optical sensor 100. On the other hand, in the multi-point mode, the optical sensor 100 moves between multiple positions on the object while projecting light, and detects the distance between the optical sensor 1 and each of the multiple designated reflection positions.

Now, with reference to FIG. 5, an example of distance detection to an object in each of single-point mode and multi-point mode will be described. In this example, the spot aimed at the object is called the target spot, and this target spot is set as the reference position. In this example, the direction of this target spot is set as the direction of the reference axis. Also, in this example, the multiple specified reflection positions are set as points a to d on the object. In this example, the direction parallel to the direction of the reference axis is set as the Z-axis direction, the direction perpendicular to the reference axis is set as the X-axis direction, and the direction perpendicular to the Z-axis and X-axis is set as the Y-axis direction.

As shown in Fig. 5A, for example, in the single-point mode, the optical sensor 100 projects a detection light in the direction of a target spot within the deflection range. The optical sensor 100 calculates the distance between the target spot and the optical sensor based on a detection signal obtained by projecting the detection light _L1 . The detection distance from the target spot, which is the calculated reference position, is set to 2520 mm.

As shown in FIG. 5B, for example, in the multi-point mode, the optical sensor 100 projects the detection light L1 in the direction of two points (points a and c) along the X-axis direction and two points (points b and d) along the Y-axis direction of two orthogonal axial directions (X-axis direction and _Y -axis direction shown in the figure), totaling four points. When projecting the detection light in the direction of points a to d, the optical sensor 100 adjusts the optical axis of the detection light to move the reflection position on the target object. The optical sensor 100 calculates the distance between each of points a to d and the optical sensor based on the detection signal obtained by projecting the detection light. The calculated detection distances of each point are, for example, 2510 mm for point a, 2515 mm for point b, 2520 mm for point c, and 2520 mm for point d. In this case, since the Z-axis distances of points a and b calculated from the detection distances of points a and b are smaller than the distances at the reference position, it is estimated that the periphery of point a and the periphery of point b are concave. On the other hand, since the Z-axis distances of points a and b calculated from the detection distances of points c and d are the same as the distances at the reference position, it is estimated that the areas around points c and d are flat. In this way, the optical sensor 100 can be used to estimate the unevenness of an object by detecting distances at multiple points on the object.

An example of the operation of the optical sensor 100 to detect the distance to an object and the displacement of the object will be described with reference to Fig. 6. Note that the order of the processes shown below is one example and may be changed as appropriate. Note that in this example, N indicates a natural number and has an initial value of "1". Also, in this example, it is assumed that angles from 1 to N _E (N _E is the last number) with respect to the reference axis are specified in advance via the receiving unit and stored in the storage unit 180.

As shown in FIG. 6, the light-emitting element 120 of the optical sensor 100 emits detection light (step S10).

Next, when the operating mode is the first mode ("first mode" in step S11), the light receiving element 140 receives the detection light reflected from the object and outputs a detection signal (step S12). Next, the distance calculation unit 112 calculates the distance between the reflection position on the object and the optical sensor based on the detection signal obtained by projecting the detection light (step S13). The distance calculation unit 112 outputs detection information including distance information indicating the calculated distance (step S14).

Next, when the operating mode is the second mode ("second mode" in step S11), the light projection adjustment unit 111 drives the optical axis adjustment element 130 so that the angle is the Nth specified angle, and the optical axis adjustment element 130 adjusts the optical axis of the detection light projected from the light projection element so that it forms the Nth specified angle with respect to the reference axis (step S15).

Next, the light receiving element 140 receives the detection light reflected at the Nth reflection position on the object and outputs a detection signal (step S16). Next, the distance calculation unit 112 calculates the distance between the Nth reflection position on the object and the optical sensor based on the detection signal obtained by projecting the detection light (step S17).

Next, if the (N+1)th angle is specified (YES in step S18), the control unit 110 increments N (step S19) and returns to the state before step 10.

Next, if the (N+1)th angle is not specified (NO in step S18), the detection distances at each of the multiple reflection positions are compared with each other to calculate the amount of displacement parallel to the direction of the reference axis between the first position and the second position among the multiple positions (step S20). Next, the control unit 110 outputs detection information including the calculated detection distance and amount of displacement (step S21).

The above-described embodiments are intended to facilitate understanding of the present invention, and are not intended to limit the present invention. The elements of the embodiments, as well as their arrangements, materials, conditions, shapes, sizes, etc., are not limited to those exemplified, and may be modified as appropriate. Furthermore, configurations shown in different embodiments may be partially substituted or combined.

[Modification]
Although the present invention has been described based on the above embodiment, the following cases are also included in the present invention.

[Modification 1]
In the above embodiment, an example in which a liquid crystal device is used for the optical axis adjustment element 130 has been described, but the optical axis adjustment element 130 is not limited to this. Other examples of the optical axis adjustment element 130 that can be used include a MEMS mirror, an optical phased array, and an electro-optical crystal. If visible light is not required, a slow light using near-infrared light can also be used for the optical axis adjustment element 130.

[Modification 2]
In the above embodiment, an example has been described in which the optical axis is adjusted to form an angle with respect to a reference axis that is stored in the storage unit 180 in order to calculate the distance at multiple points on the target object, but the method of adjusting the optical axis is not limited to this. As another example, the storage unit 180 may provide a reference point (e.g., the reference position in Figs. 3 to 5) within the deflection range, and store the displacement amount in the X-axis direction and the displacement amount in the Y-axis direction from the reference point for each position on the target object (e.g., points a and b in Figs. 3 and 4). Then, the light projection adjustment unit 111 may drive the optical axis adjustment element 130 so that the detection light _L1 is projected to a position displaced by these displacement amounts in the X-axis direction and the Y-axis direction from the reference point, and cause the light projection element 120 and the light receiving element 140 to perform the detection process.

A part or all of this embodiment can be described as follows, but is not limited to the following:

[Additional Note]
An optical sensor (100),
A light-projecting element (120) for projecting a detection light (L ₁ );
an adjustment unit (130) that adjusts the optical axis of the detection light (L ₁ ) projected from the light projecting element (120) so that the optical axis forms an angle with a reference axis;
a light receiving element (140) that receives the detection light ( _L2 ) reflected by an object and outputs a detection signal;
a distance calculation unit (112) that calculates a distance between each of a plurality of positions on the object and the optical sensor (100) by a ToF method based on a detection signal obtained by projecting the detection light onto each of a plurality of positions on the object by driving the adjustment unit (130);
An optical sensor (100) comprising:

100...Optical sensor, 101...Housing, 102...Transmission window, 103...Cable, 110...Control unit, 111...Light projection adjustment unit, 112...Distance calculation unit, 113...Displacement amount calculation unit, 114...Inclination calculation unit, 115...Switching 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

Claims (8)

An optical sensor comprising:
a light-projecting element that projects detection light;
an adjustment unit that adjusts an optical axis of the detection light projected from the light projecting element so that the optical axis forms an angle with a reference axis;
a light receiving element that receives the detection light reflected by an object and outputs a detection signal;
a distance calculation unit that calculates a distance between each of a plurality of positions on the object and the optical sensor by a ToF method based on a detection signal obtained by projecting the detection light onto each of a plurality of positions on the object by driving the adjustment unit;
a displacement amount calculation unit that calculates a distance between each of the plurality of positions and the optical sensor in a direction parallel to the reference axis based on the distance at each of the plurality of positions and the angle with respect to the reference axis, thereby calculating an amount of displacement between a first position and a second position among the plurality of positions in a direction parallel to the reference axis;
An optical sensor comprising: The optical sensor according to claim 1 , further comprising a tilt calculation unit that calculates a tilt of the object between the first position and the second position based on the amount of displacement. A switching unit that switches an operation mode of the optical sensor between a first mode and a second mode,
The adjustment unit adjusts the optical axis to project light in a specific direction in the first mode, and adjusts the optical axis to project light in a plurality of directions in the second mode;
the distance calculation unit calculates a distance between a single position on the object and the optical sensor based on a detection signal obtained by projecting the detection light in the first mode, and calculates a distance between each of a plurality of positions on the object and the optical sensor based on a detection signal obtained by projecting the detection light in the second mode.
3. The optical sensor according to claim 1 or 2 . the adjustment unit includes an optical axis adjustment element that is accommodated in a housing together with at least the light emitting element and the light receiving element and adjusts an optical axis of the detection light emitted from the light emitting element,
The optical sensor according to claim 1 . The optical axis adjustment element includes a liquid crystal device that adjusts the optical axis of the detection light by deflecting the detection light.
5. The optical sensor according to claim 4 . A storage unit that stores one or more angles with respect to the reference axis,
The adjustment unit adjusts the optical axis of the detection light based on the one or more angles stored in the storage unit.
The optical sensor according to claim 1 . A control method for an optical sensor including a light-projecting element that projects detection light, an adjustment unit that adjusts an optical axis of the detection light projected from the light-projecting element so as to form an angle with a reference axis, and a light-receiving element that receives the detection light reflected by an object and outputs a detection signal, comprising:
a distance calculation step of calculating a distance between each of the plurality of positions and the optical sensor by a ToF method based on a detection signal obtained by projecting the detection light onto each of the plurality of positions on the object by driving the adjustment unit;
a displacement amount calculation step of calculating a distance between each of the plurality of positions and the optical sensor in a direction parallel to the direction of the reference axis based on the distance at each of the plurality of positions and the angle with respect to the reference axis, thereby calculating a displacement amount between a first position and a second position among the plurality of positions in a direction parallel to the direction of the reference axis;
A method for controlling an optical sensor comprising the steps of: A control program for an optical sensor including a light-projecting element that projects detection light, an adjustment unit that adjusts an optical axis of the detection light projected from the light-projecting element so as to form an angle with a reference axis, and a light-receiving element that receives the detection light reflected by an object and outputs a detection signal,
a distance calculation step of calculating a distance between each of the plurality of positions and the optical sensor by a ToF method based on a detection signal obtained by projecting the detection light onto each of the plurality of positions on the object by driving the adjustment unit;
a displacement amount calculation step of calculating a distance between each of the plurality of positions and the optical sensor in a direction parallel to the direction of the reference axis based on the distance at each of the plurality of positions and the angle with respect to the reference axis, thereby calculating a displacement amount between a first position and a second position among the plurality of positions in a direction parallel to the direction of the reference axis;
A control program for an optical sensor that causes a computer to execute the above.

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