Optical sensor system

Abstract

To easily install a photoelectric switch.SOLUTION: An optical sensor system 100 comprises a light projection section 110, a lens 120, a light receiving section 130, a light receiving sensitivity adjustment section 140, and a light receiving sensitivity control section 150. The light projection section 110 projects light to a detection region. The lens 120 condenses the light projected by the light projection section 110 and reflected in the detection region. The light receiving section 130 has a plurality of light receiving elements and receives the light condensed by the lens 120 for each light receiving element. The light receiving sensitivity adjustment section 140 adjusts light receiving sensitivity for each light receiving element of the light receiving section. The light receiving sensitivity control section 150 compares a first amount of light received by each light receiving element in a state where a detection target is present in the detection region in advance with a second amount of light received by each light receiving element in a state where the detection target is not present in the detection region, and gives a light receiving sensitivity setting signal to the light receiving sensitivity adjustment section 140 on the basis of a difference between the first and second amounts of light received for each light receiving element.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an optical sensor system. [Background technology]

[0002] Conventionally, photoelectric switches (photoelectric sensors) that detect objects and people are installed at baggage transport sites in factories and at platform doors installed on train platforms. Photoelectric switches are composed of a light-emitting part that emits light and a light-receiving part that receives the light, and convert the change in the amount of light that enters the light-receiving part into an electrical signal. Therefore, photoelectric switches can determine the presence or absence of the object or person to be detected (hereinafter also referred to as the target) by outputting the change in the amount of light at the light-receiving part caused by the projected light being blocked or reflected by an object. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-226997 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the conventional technology has room for improvement in the installation work of the photoelectric switch. For example, the conventional technology requires a lot of man-hours to install the photoelectric switch because fine adjustment of the optical axis and installation of slits are required to prevent erroneous detection due to reflected light from surrounding objects or objects other than the target. [Means for solving the problem]

[0005] In order to solve the above-mentioned problems, the optical sensor system of the present invention is characterized by comprising a light-projecting unit that projects light onto a detection area, a lens that collects the light projected by the light-projecting unit and reflected at the detection area, a light-receiving unit having a plurality of light-receiving elements that receive the light collected by the lens for each of the light-receiving elements, a light-receiving sensitivity adjustment unit that adjusts the light-receiving sensitivity of each of the light-receiving elements of the light-receiving unit, and a light-receiving sensitivity control unit that compares a first amount of light received by each light-receiving element when a detection target is previously present in the detection area with a second amount of light received by each light-receiving element when a detection target is not present in the detection area, and provides a light-receiving sensitivity setting signal to the light-receiving sensitivity adjustment unit based on the difference between the first and second amounts of light received for each light-receiving element. Effect of the Invention

[0006] According to the present invention, an effect is achieved in that the photoelectric switch can be easily installed. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing an example of a conventional photoelectric switch and an optical sensor system according to this embodiment. [Diagram 2] FIG. 2 is a diagram illustrating an optical sensor system according to the embodiment. [Diagram 3] FIG. 3 is a diagram illustrating an example of the configuration of an optical sensor system according to the embodiment. [Figure 4] FIG. 4 is a diagram showing data stored in the storage unit according to the embodiment. [Diagram 5] FIG. 5 is a diagram showing a specific example of processing by the optical sensor system according to the embodiment. [Figure 6] FIG. 6 is a diagram showing the relationship between the position of the light receiving element and the detection of a target according to the embodiment. [Figure 7] FIG. 7 is a flowchart illustrating an example of a processing procedure of the optical sensor system according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of an optical sensor system according to the present application will be described in detail with reference to the drawings. Note that the optical sensor system according to the present application is not limited to the embodiment.

[0009] 1. Introduction Today, photoelectric switches are installed in various work sites to detect the presence or absence of a target without contact. As mentioned above, photoelectric switches detect the presence of a target based on the amount of light that enters the light receiving section, so they require careful adjustments when installed so as not to detect reflected light from anything other than the target.

[0010] For example, when a transmission type photoelectric switch is installed at a site where luggage is transported, targeting luggage moving on a conveyor or suspended luggage, the optical axis is finely adjusted so as not to detect light reflected from the wall of the device. Also, when a photoelectric switch is installed at a site where luggage is transported, targeting only the tool of a tool changer of a machine tool, the beam is narrowed using a slit or the like so as not to erroneously detect areas surrounding the target.

[0011] Furthermore, for example, when a photoelectric switch is installed on a platform door at a train platform to target people entering the platform, the optical axis is finely adjusted to prevent erroneous detection due to reflected light from the vehicle.Also, for example, when a reflective photoelectric switch is installed on a circuit board during device assembly to target a circuit board, the optical axis is finely adjusted to prevent erroneous detection of surrounding rollers, etc.

[0012] In other words, when installing a photoelectric switch, it is necessary to make fine adjustments to the optical axis or to narrow the beam by using slits depending on the type of target and the installation environment. Therefore, with the conventional technology, there is a problem that a large amount of man-hours are required when installing a photoelectric switch.

[0013] In view of the problems of the conventional technology described above, the optical sensor system (photoelectric switch) of this embodiment does not require fine adjustment of the optical axis or installation of a slit, and the photoelectric switch can be easily installed.

[0014] Here, a difference in configuration between a photoelectric switch in the prior art and the optical sensor system 100 according to this embodiment will be described. Fig. 1 is a diagram showing an example of a conventional photoelectric switch and an optical sensor system according to this embodiment.

[0015] First, the elements common to the conventional photoelectric switch and the optical sensor system 100 will be described. In the example shown in (1) and (2) of FIG. 1, a "photodiode" which is a light receiving element receives light and converts the received light into an electric current. The converted electric current is then converted from a current to a voltage and the signal is amplified by an "I / V conversion circuit" and an "amplification circuit". After that, when the magnitude of the voltage becomes equal to or greater than a threshold value by a "judgment circuit" and a "threshold circuit", the detection of the target is output by an "output circuit". Then, the light receiving sensitivity of the light receiving element is adjusted by a "sensitivity control circuit", a "button adjustment", and a "sensitivity setting circuit" so that the target can be detected with high accuracy.

[0016] Next, we will explain the differences between conventional photoelectric switches and optical sensor systems. As shown in Figure 1 (1), conventional photoelectric switches have a single photodiode, so target detection depends on whether light is properly irradiated onto the photodiode. This requires fine adjustment of the optical axis and the installation of slits so that light is properly irradiated onto the photodiode.

[0017] In contrast, the optical sensor system 100 shown in the example of Fig. 1 (2) has a plurality of photodiodes in the light receiving section 130, combines the currents from the respective photodiodes, converts the combined current into a voltage signal, and compares the value with a threshold to determine the presence or absence of a target. As a result, by adjusting the signal sensitivity from each photodiode, even if light reflected from a wall or the like other than the target enters the light receiving section, the optical sensor system 100 can prevent erroneous detection and detect only the target as long as the light receiving sensitivity of the photodiode into which the reflected light enters is set low, thereby making it possible to detect the target without fine adjustment of the optical axis or installation of a slit.

[0018] 2. Overall Structure Next, the overall configuration of the optical sensor system according to this embodiment will be described. Fig. 2 is a diagram showing the optical sensor system according to the embodiment. The optical sensor system 100 shown in Fig. 2 projects light from a light projecting unit 110 to a target 200, and receives the light reflected from the target 200 by a light receiving unit 130 via a lens 120.

[0019] In the optical sensor system 100, the light receiving unit 130, the light sensitivity adjustment unit 140, and the light sensitivity control unit 150 are connected to each other, and the light sensitivity of each of the multiple light receiving elements that make up the light receiving unit 130 is individually set by processing of the light sensitivity adjustment unit 140 and the light sensitivity control unit 150.

[0020] Note that the optical sensor system 100 in FIG. 2 shows an example of a reflective photoelectric switch that receives light reflected from a target and determines the presence or absence of a target, but is not limited to this and may be applied to a transmissive photoelectric switch or a retroreflective photoelectric switch.

[0021] The optical sensor system 100 projects light onto a detection area, collects the light reflected by the detection area, and receives the collected light for each of the multiple light receiving elements. The optical sensor system 100 then compares a first amount of light received by each light receiving element when a detection target is present in the detection area with a second amount of light received by each light receiving element when a detection target is not present in the detection area, and adjusts the light receiving sensitivity of each light receiving element based on the difference between the first and second amounts of light received for each light receiving element.

[0022] For example, the optical sensor system 100 projects light onto a detection area of ​​the target 200 using the light projecting unit 110, collects the light reflected by the target 200 using the lens 120, and then receives the collected light using each photodiode constituting the light receiving unit 130. Then, the optical sensor system 100 calculates, for example, a difference between a first amount of light received by each light receiving element when the target 200 is present and a second amount of light received by each light receiving element when the target 200 is not present.

[0023] Thereafter, the optical sensor system 100 transmits a light sensitivity setting signal from the light sensitivity control unit 150 to the light sensitivity adjustment unit 140 so as to set the light sensitivity of the light receiving elements whose difference is equal to or greater than a preset threshold value relatively high, and adjusts the light sensitivity of each light receiving element using the light sensitivity setting signal.

[0024] The target 200 is an object to be detected by the optical sensor system 100. For example, the target 200 is a baggage carried by a conveyor, a part of a machine tool, a person, etc., and is not particularly limited as long as it is an object that blocks or reflects irradiated light.

[0025] 3. Configuration of the optical sensor system 100 Next, a configuration of the optical sensor system 100 shown in Fig. 2 will be described. Fig. 3 is a diagram showing a configuration example of the optical sensor system according to the embodiment. As shown in Fig. 3, the optical sensor system 100 according to the embodiment has a light projecting unit 110, a lens 120, a light receiving unit 130, a light receiving sensitivity adjusting unit 140, a light receiving sensitivity control unit 150, and a storage unit 160.

[0026] The light projecting unit 110 projects light onto a detection area. For example, the light projecting unit 110 projects light from a light source onto a detection area in which a target 200 to be detected is present. Here, the light source may be, for example, a device that irradiates visible light such as a red light emitting diode or a red laser, or may be a device that irradiates invisible light such as an infrared light emitting diode.

[0027] The lens 120 collects the light projected by the light projecting unit 110 and reflected in the detection area. For example, the lens 120 collects the light projected by the light projecting unit 110 and reflected by the target 200 or a reflector in the detection area.

[0028] The storage unit 160 is realized by a storage device such as a RAM (Random Access Memory) or a hard disk. The storage unit 160 stores data and programs necessary for various processes by the light sensitivity adjustment unit 140 and the light sensitivity control unit 150, and has a light amount data storage unit 161 and a light sensitivity setting data storage unit 162 as units closely related to the present invention.

[0029] The received light amount data storage unit 161 stores a first amount of received light and a second amount of received light received by the light receiving unit 130 described later, and the difference between them. Here, the data stored in the received light amount data storage unit 161 will be described. Fig. 4 is a diagram showing data stored in the storage unit according to the embodiment.

[0030] As shown in FIG. 4(1), the received light amount data storage unit 161 is composed of items such as a "light receiving element number," a "first amount of received light," a "second amount of received light," and a "difference." The "light receiving element number" stores a number assigned to each light receiving element configured in the light receiving unit 130. The "first amount of received light" stores the amount of received light when the corresponding light receiving element has a target, and the "second amount of received light" stores the amount of received light when the corresponding light receiving element does not have a target. The "difference" stores the difference between the first amount of received light and the second amount of received light.

[0031] The light sensitivity setting data storage unit 162 stores the light sensitivity set for each light receiving element by the light sensitivity adjustment unit 140. Here, the data stored in the light sensitivity setting data storage unit 162 will be described.

[0032] As shown in FIG. 4(2), the light sensitivity setting data storage unit 162 is configured with, for example, items of "light receiving element number" and "light sensitivity." The "light sensitivity" stores the light sensitivity set for the corresponding light receiving element. Here, the light sensitivity of a light receiving element set for detection by the light sensitivity control unit 150 described later is set to be about 10 times higher than that of a light receiving element not for detection. Specifically, "light sensitivity: 30" is set for "light receiving element: 1" for detection, and "light sensitivity: 3" is set for "light receiving element: 2" for non-detection.

[0033] Returning to the description of Fig. 3, the light receiving unit 130 has a plurality of light receiving elements, and receives the light collected by the lens 120 for each of the light receiving elements. For example, the light receiving unit 130 has a plurality of photodiodes arranged two-dimensionally, and receives the reflected light from the target 200 collected by the above-mentioned lens 120 for each of the photodiodes.

[0034] The light sensitivity adjustment unit 140 adjusts the light sensitivity of each light receiving element of the light receiving unit 130. For example, the light sensitivity adjustment unit 140 sets the light sensitivity of each photodiode constituting the light receiving unit 130 individually based on a light sensitivity setting signal from a light sensitivity control unit 150 (described later), and stores the set light sensitivity in the light sensitivity setting data storage unit 162.

[0035] The light sensitivity control unit 150 compares a first amount of light received by each light receiving element when the detection target is present in the detection area with a second amount of light received by each light receiving element when the detection target is not present in the detection area, and provides a light sensitivity setting signal to the light sensitivity adjustment unit 140 based on the difference between the first and second amounts of light received for each light receiving element.

[0036] For example, the light sensitivity control unit 150 compares a first amount of light received by each light receiving element when the detection target is present in the detection area with a second amount of light received by each light receiving element when the detection target is not present in the detection area, calculates the difference between the first and second amounts of light received for each light receiving element, and if the difference in the amount of light received falls below a predetermined threshold, provides a light sensitivity setting signal to the light sensitivity adjustment unit 140 to lower the light sensitivity of the corresponding light receiving element.

[0037] For example, first, in a state where the target 200 is present, the light sensitivity control unit 150 stores the amount of light received by each photodiode constituting the light receiving unit 130 in the light receiving amount data storage unit 161. Next, in a state where the target 200 is not present, the light sensitivity control unit 150 stores the amount of light received by each photodiode constituting the light receiving unit 130 in the light receiving amount data storage unit 161.

[0038] Then, the light sensitivity control unit 150 sets the photodiode for which the difference between the first amount of received light and the second amount of received light is equal to or greater than a preset threshold as a detection photodiode. After that, the light sensitivity control unit 150 transmits a signal to the light sensitivity adjustment unit 140 to relatively lower the light sensitivity of the other photodiodes not for detection so as to relatively increase the light sensitivity of the detection photodiode.

[0039] Here, for example, in the process of measuring the amount of received light, the light sensitivity control unit 150 transmits a signal for setting the sensitivity of the photodiodes other than the measurement target to "0" and a signal for setting the sensitivity of the measurement target photodiode to a "reference value," and measures the amount of received light of the measurement target photodiode by making the combined current equal to the current flowing through the measurement target photodiode. Then, the light sensitivity control unit 150 performs the above-mentioned process in order for each photodiode constituting the light receiving unit 130.

[0040] As a result, even if the light sensitivity control unit 150 has a configuration in which the currents from the respective photodiodes are combined, it can measure the amount of light received by each photodiode individually. Note that the light sensitivity control unit 150 can store, for example, the value of the current flowing through each photodiode in the light reception amount data storage unit 161 as the amount of light received by each photodiode.

[0041] Furthermore, the light sensitivity control unit 150 provides an initial light sensitivity setting signal for the light receiving element to the light sensitivity adjustment unit 140 based on the second amount of received light. For example, before measuring the first amount of received light and the second amount of received light of each photodiode described above, the light sensitivity control unit 150 measures the second amount of received light (amount of light in the detection environment) in a state in which the target 200 is not present, and transmits an initial light sensitivity setting signal to the light sensitivity adjustment unit 140 so as to set the light sensitivity low when the amount of light in the detection environment is large (the detection environment is bright) and set the light sensitivity high when the amount of light in the detection environment is small (the detection environment is dark).

[0042] Here, the initial light sensitivity is a "reference value" light sensitivity set as the sensitivity of the photodiode to be measured in the above-mentioned process of measuring the amount of received light, and is set by the light sensitivity adjustment unit 140 based on an initial light sensitivity setting signal transmitted from the light sensitivity control unit 150. Note that, when the above-mentioned process of setting the other light receiving elements not for detection to a relatively low value is performed, the initial light sensitivity may be set for the light receiving element for detection.

[0043] Furthermore, the light sensitivity control unit 150 provides an initial light sensitivity setting signal for the light receiving element to the light sensitivity adjustment unit 140 in correspondence with the type of detection target. For example, the light sensitivity control unit 150 transmits to the light sensitivity adjustment unit 140 an initial light sensitivity setting signal in correspondence with the amount of light reflection that changes depending on the material and shape of the surface of the target 200.

[0044] Here, the light sensitivity control unit 150 may transmit an initial light sensitivity setting signal based on information regarding the type of the target 200 that is preset from the outside, or the optical sensor system 100 may automatically recognize the type of the target 200 and transmit an initial light sensitivity setting signal.

[0045] The process of setting the light sensitivity of each light receiving element by the light sensitivity adjustment unit 140, the process of measuring the amount of light received by each light receiving element by the light sensitivity control unit 150, and the process of setting the detection light receiving elements may be performed automatically or partly manually.

[0046] 4. Examples Next, a specific example of processing performed by the optical sensor system 100 according to this embodiment will be described. The optical sensor system 100 can appropriately determine the presence or absence of the target 200 by switching between an "adjustment mode" in which a light receiving element for detection is set based on the first amount of received light and the second amount of received light of each light receiving element, and a "detection mode" in which the target 200 present in the detection area is detected. The "adjustment mode" and "detection mode" will be described in order below.

[0047] (4-1. Adjustment mode) First, the process performed in the adjustment mode will be described. Fig. 5 is a diagram showing a specific example of the process performed by the optical sensor system according to the embodiment. Fig. 5 shows the processes (1) to (3) performed in the adjustment mode in order. Note that in the optical sensor system 100, the sensitivity of the "reference value" set in the light receiving element to be measured is preset as "30".

[0048] First, the light sensitivity adjustment unit 140 sets the light sensitivity of "light receiving element number: 1" to a reference value of "30", and sets the light sensitivity of the other light receiving elements to "0". After that, the light sensitivity control unit 150 measures the amount of light received by "light receiving element number: 1" (the value of the current flowing through the circuit) with the target 200 present in the detection area, and stores it as the first amount of light received in the light receiving amount data storage unit 161. Then, the light sensitivity adjustment unit 140 and the light sensitivity control unit 150 perform the above-mentioned series of processes for each of the light receiving elements from "light receiving element number: 2" onwards, and measure the first amount of light received by each light receiving element.

[0049] Next, when the target 200 is not present in the detection area, the light sensitivity control unit 150 performs the above-mentioned series of processes on each light receiving element to measure the amount of light received by each light receiving element and stores the amount of light received by each light receiving element in the light receiving amount data memory unit 161 as a second amount of light received.

[0050] Thereafter, the light sensitivity control unit 150 calculates the difference between the first amount of received light and the second amount of received light for each light receiving element, and determines that the light receiving element for which the difference is greater than a preset threshold value is the light receiving element for which the amount of received light has changed depending on the presence or absence of the target 200, and sets it as the light receiving element for detection.

[0051] (4-2. Detection mode) Next, the process performed in the detection mode will be described. For example, the light sensitivity control unit 150 transmits a light sensitivity setting signal to the light sensitivity adjustment unit 140 so as to set the light sensitivity of the light receiving element for detection to "30" and the light sensitivity of the other light receiving elements to "3" based on the information of the light receiving element for detection set in the adjustment mode. Then, the light sensitivity adjustment unit 140 sets the light sensitivity of each light receiving element according to the light sensitivity setting signal, and stores the set light sensitivity in the light sensitivity setting data storage unit 162.

[0052] As a result, when light is received by the detection light receiving element, a large current flows in the optical sensor system 100, and the target 200 can be detected because a current exceeding a threshold value flows in the judgment circuit.

[0053] Here, the relationship between the sensitivity setting of the light receiving element and the detection of the target 200 will be described. Fig. 6 is a diagram showing the relationship between the position of the light receiving element and the detection of the target according to the embodiment. Fig. 6 shows the photodiodes constituting the light receiving unit 130, the lens 120, and objects (1) to (3), and indicates that the object (2) is the target 200.

[0054] Also, in the example of FIG. 6, the light receiving unit 130 has the sensitivity of the photodiodes in “area B” set to be relatively high through a series of processes in the adjustment mode and detection mode described above, and the sensitivity of the photodiodes in other areas set to be relatively low.

[0055] 6, the light reflected by objects (1) to (3) is received by parts (area A to area C) of the photodiodes of the light receiving unit 130 via the lens 120. Specifically, the light reflected by object (1) is received by the photodiode in "area C," the light reflected by object (2) is received by the photodiode in "area B," and the light reflected by object (3) is received by the photodiode in "area A."

[0056] Here, the light reflected by object (2), which is the target 200, is received by the photodiode in "area B," which has a high light receiving sensitivity, so the current flowing through the circuit is equal to or exceeds the threshold, and the target 200 is appropriately detected. On the other hand, the light reflected by object (1) or (3) is received by the photodiode in "area C" or "area A," which has a low light receiving sensitivity, so the current flowing through the circuit is small and the target 200 is not detected.

[0057] In other words, by setting the sensitivity of the detection light receiving element set in the adjustment mode to be relatively high, the optical sensor system 100 allows a current equal to or greater than the threshold value to flow through the circuit only when the detection light receiving element receives light reflected by the target 200 present in the detection area, thereby enabling the presence or absence of a target in the detection area to be appropriately determined.

[0058] 5. Processing Procedure of the Optical Sensor System Next, an example of a processing procedure for setting the light receiving sensitivity of each light receiving element by the optical sensor system 100 according to the embodiment will be described with reference to Fig. 7. Fig. 7 is a flowchart showing an example of a processing procedure of the optical sensor system according to the embodiment. Note that the following steps may be performed in a different order, and some steps may be omitted.

[0059] The light sensitivity control unit 150 of the optical sensor system 100 measures the amount of light received by each light receiving element in the presence of the target 200 (first amount of light received) (S101). Next, the light sensitivity control unit 150 measures the amount of light received by each light receiving element in the absence of the target 200 (second amount of light received) (S102).

[0060] Next, the light sensitivity control unit 150 calculates the difference between the first amount of received light and the second amount of received light for each light receiving element (S103).Then, the light sensitivity control unit 150 sets the light receiving element for which the difference is greater than a threshold value as the light receiving element for detection (S104).

[0061] Thereafter, the light sensitivity adjusting unit 140 sets the light sensitivity of each light receiving element by a light sensitivity setting signal that sets the light sensitivity of the detection light receiving element to high and the light sensitivity of the other light receiving elements to low (S105). Then, the optical sensor system 100 ends the light sensitivity setting process.

[0062] 6. Effects of the embodiment As described above, the optical sensor system 100 according to this embodiment includes the light projecting unit 110, the lens 120, the light receiving unit 130, the light sensitivity adjusting unit 140, and the light sensitivity control unit 150.

[0063] The light-projecting unit 110 projects light onto the detection area. The lens 120 collects the light projected by the light-projecting unit 110 and reflected by the detection area. The light-receiving unit 130 has a plurality of light-receiving elements, and receives the light collected by the lens 120 for each of the light-receiving elements. The light-receiving sensitivity adjusting unit 140 adjusts the light-receiving sensitivity of each of the light-receiving elements of the light-receiving unit 130.

[0064] The light sensitivity control unit 150 compares a first amount of light received by each light receiving element when the detection target is present in the detection area with a second amount of light received by each light receiving element when the detection target is not present in the detection area, and provides a light sensitivity setting signal to the light sensitivity adjustment unit 140 based on the difference between the first and second amounts of light received for each light receiving element.

[0065] As a result, the optical sensor system 100 detects the target 200 by setting the light receiving sensitivity of the light receiving element, among the multiple light receiving elements, whose received light amount changes between the state where the target 200 is present and the state where the target 200 is not present, relatively high, so that if reflected light is received by any of the multiple installed light receiving elements, the target 200 can be detected. Therefore, the optical sensor system 100 allows the photoelectric switch to be easily installed without fine adjustment of the optical axis, installation of slits, or other adjustments.

[0066] In addition, the light sensitivity control unit 150 of the optical sensor system 100 compares a first amount of light received by each light receiving element when the detection target is present in the detection area with a second amount of light received by each light receiving element when the detection target is not present in the detection area, calculates the difference between the first and second amounts of light received for each light receiving element, and when the difference in the amount of light received falls below a predetermined threshold, provides a light sensitivity setting signal to the light sensitivity adjustment unit 140 to lower the light sensitivity of the corresponding light receiving element.

[0067] As a result, the optical sensor system 100 can set the light receiving sensitivity of the light receiving elements whose amount of received light does not change much between the presence and absence of the target 200 to a relatively low level, thereby preventing a large current from flowing through a light receiving element that receives a high amount of light regardless of the presence or absence of the target 200, and thereby enabling the target to be detected appropriately.

[0068] Furthermore, the light sensitivity control unit 150 of the optical sensor system 100 provides an initial light sensitivity setting signal for the light receiving element based on the second amount of received light to the light sensitivity adjustment unit 140. This allows the optical sensor system 100 to set the initial light sensitivity to be set in the light receiving element to be measured and the light receiving element for detection according to the amount of light in the detection environment (the second amount of received light).

[0069] Furthermore, the light sensitivity control unit 150 of the optical sensor system 100 provides an initial light sensitivity setting signal for the light receiving element to the light sensitivity adjustment unit 140 in accordance with the type of detection target. This allows the optical sensor system 100 to set the initial light sensitivity to be set for the light receiving element to be measured and the light receiving element for detection in accordance with the type of detection target.

[0070] [7. Other] Of the processes described in the above embodiments, all or part of the processes described as being performed automatically can be performed manually, or all or part of the processes described as being performed manually can be performed automatically by a known method. In addition, the information including the processing procedures, specific names, various data and parameters shown in the above documents and drawings can be changed arbitrarily unless otherwise specified. For example, the various information shown in each drawing is not limited to the illustrated information.

[0071] In addition, each component of each device shown in the figure is a functional concept, and does not necessarily have to be physically configured as shown in the figure. In other words, the specific form of distribution and integration of each device is not limited to that shown in the figure, and all or part of them can be functionally or physically distributed and integrated in any unit according to various loads, usage conditions, etc.

[0072] The above-mentioned components include those that can be easily imagined by a person skilled in the art, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the above-mentioned embodiments can be appropriately combined within a range that does not cause contradictions in the processing contents.

[0073] Moreover, the above-mentioned "section, module, unit" can be read as "means" or "circuit", etc. For example, a control section can be read as control means or a control circuit.

[0074] Although some of the embodiments of the present invention have been described in detail above with reference to the drawings, these are merely examples, and the present invention can be embodied in other forms that incorporate various modifications and improvements based on the knowledge of those skilled in the art, including the forms described in the Disclosure of the Invention section. [Explanation of symbols]

[0075] 100 Optical Sensor System 110 Light projector 120 Lens 130 Light receiving part 140 Light receiving sensitivity adjustment unit 150 Light receiving sensitivity control section 160 Storage section 161 Light receiving amount data storage unit 162 Light receiving sensitivity setting data storage section 200 Target

Claims

1. a light projection unit that projects light onto a detection area; a lens that collects light projected by the light projecting unit and reflected by the detection area; a light receiving section including a plurality of light receiving elements, each of which receives the light collected by the lens; a light-receiving sensitivity adjustment unit that adjusts the light-receiving sensitivity of each light-receiving element of the light-receiving unit; a light-receiving sensitivity control section that compares a first amount of light received by each of the light-receiving elements in a state in which a detection target is present in the detection area with a second amount of light received by each of the light-receiving elements in a state in which the detection target is not present in the detection area, and provides a light-receiving sensitivity setting signal to the light-receiving sensitivity adjustment section based on a difference between the first and second amounts of light received for each of the light-receiving elements; An optical sensor system comprising:

2. 2. The optical sensor system of claim 1, The light receiving sensitivity control unit is A first amount of light received by each of the light receiving elements when the detection target is present in the detection area is compared with a second amount of light received by each of the light receiving elements when the detection target is not present in the detection area, and a difference between the first and second amounts of light received is calculated for each of the light receiving elements. When the difference between the amounts of light received falls below a predetermined threshold, a light receiving sensitivity setting signal is provided to the light receiving sensitivity adjustment unit so as to lower the light receiving sensitivity of the corresponding light receiving element. An optical sensor system comprising:

3. 3. The optical sensor system according to claim 1, The light receiving sensitivity control unit is providing an initial light-receiving sensitivity setting signal for the light-receiving element to the light-receiving sensitivity adjustment unit based on the second amount of received light; An optical sensor system comprising:

4. 3. The optical sensor system according to claim 1, The light receiving sensitivity control unit is providing an initial light-receiving sensitivity setting signal of the light-receiving element to the light-receiving sensitivity adjustment unit in correspondence with the type of the detection target; An optical sensor system comprising:

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