JP2007322152A - Object sensor control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent malsensing caused by disturbance light and stabilize the sensing condition of a sensor when an object exists in the vicinity of the border of the sensing range of the sensor without increasing the number of the sensor in an object sensor control apparatus. <P>SOLUTION: The object sensor control apparatus comprises: a mode control section 11 which has a waiting mode for emitting light with a first light emission interval from a light emitting section 2 and a sensing mode for emitting light with a shorter second light emission interval and switches to the sensing mode when sensed to be "object exists" during a waiting mode; a count section 12 for counting the continuous number of sensing cycles and the continuous number of non-sensing cycles; and a judgment section 14 which determines the confirmation of sensing upon the reach of a counted value of the continuous number of the sensing cycles at a first threshold when a waiting mode is switched to a sensing mode and determines non-sensing when the continuation of the sensing cycles breaks before it reaches the first threshold. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a control device for an object detection sensor such as an automatic hand washing device or a finger sensor provided in a fluid dispenser.

Conventionally, as a hand-washing device for washing hands, fingertips, etc., it has a hand-washing water nozzle that discharges hand-washing water and discharges hand-washing water according to the user's intention to use. Is generally well known. Further, in addition to the hand washing water nozzle, a chemical liquid nozzle that discharges and supplies a chemical liquid such as a soap liquid or a disinfecting liquid and supplies the chemical liquid and the hand washing water sequentially is also commonly used.
In particular, in recent years, a sensor that detects a user's use operation such as an operation of inserting a finger under a nozzle by a sensor and can automatically discharge and supply a chemical solution and hand washing water has been widely used ( For example, see Patent Documents 1 and 2).

In addition, even in a so-called fluid dispenser that discharges and supplies a chemical solution such as a soap solution or a disinfectant solution alone, it is possible to automatically discharge and supply the chemical solution from the discharge nozzle by detecting the use operation of the user as described above with a sensor. This is known.
In the fluid dispenser and the hand washing apparatus, the “fluid” includes a foam-like one.

In a sensing sensor that senses a kind of object (sensing target object) such as a user's finger, usually a light projecting unit that constantly projects light such as infrared light, and light from the light projecting unit A light-receiving unit that can receive the reflected light when reflected by the user's finger that is put out within the sensing range, and when the light is received by the light-receiving unit, it is detected that there is an object. ing. The sensing range of the sensor is determined by the position and distance with respect to the light projecting unit and the light receiving unit.
Japanese Patent Laid-Open No. 62-156446 Japanese Patent Laid-Open No. Sho 62-156447

  However, conventionally, when disturbance light such as light from a fluorescent lamp outside the sensor system is reflected on the surface of a hand-washing sink or the like and enters the sensor light receiving unit, the object to be detected (user's In spite of the absence of a finger, there is a problem that it is erroneously detected as “there is an object”, which causes a malfunction of a hand washing device or a dispenser (hereinafter simply referred to as “device” as appropriate).

  Further, when the user's finger is put out near the boundary of the sensing range of the sensing sensor, light and non-incident light entering the sensor light receiving unit (that is, sensing and non-sensing) are repeated when the finger moves slightly. In some cases, the sensing state of the sensor becomes unstable. In such a case, the operation of the apparatus is unstable.

  To solve this problem, for example, it is conceivable to increase the detection accuracy by providing a plurality of detection sensors. In this case, however, the control of the detection sensors is complicated and the cost is high.

  Therefore, the present invention can prevent erroneous detection due to ambient light, and stabilizes the detection state of the sensor when there is an object near the boundary of the detection range of the detection sensor without increasing the number of detection sensors. The object of the present invention is to provide a control device for an object detection sensor capable of performing the above.

  For this reason, in the control device for an object detection sensor according to the first aspect of the present invention (hereinafter referred to as the first invention), the light from the light projecting unit is reflected by an object within a predetermined detection range and is received by the light receiving unit. A control device for an object detection sensor that detects that the object is within the detection range by receiving light, and includes a standby mode in which light is projected from the light projecting unit at a first light projection interval, and the first light projection. Mode control means for projecting at a second projection interval shorter than the light interval, and when the object is sensed within the sensing range during the standby mode, mode control means for switching to the sensing mode; The number of consecutive sensing cycles in which the light receiving unit projects light from the light projecting unit and receives light reflected from the object, and the light receiving unit does not receive the reflected light from the object even if light is projected from the light projecting unit. The number of consecutive sensing cycles And when the count value of the number of continuous cycles of the sensing cycle by the counting means reaches a first threshold value when the mode is switched from the standby mode to the sensing mode, it is determined that the sensing is confirmed, and the first threshold value is determined. And determining means for determining non-sensing when the continuation of the sensing cycle is interrupted before reaching.

  Further, the invention according to claim 2 of the present application (hereinafter referred to as the second invention) is the first invention until the count value of the continuous number of the sensing cycles reaches the first threshold value in the sensing mode. When the determination unit determines that the detection is not performed, the count value of the continuous number of the detection cycles by the counting unit is reset, and the detection mode is switched to the standby mode.

  Furthermore, in the invention according to claim 3 of the present application (hereinafter referred to as the third invention), in the first or second invention, the light projecting unit after the determination unit determines that the detection is confirmed in the detection mode. When a non-sensing state is detected in which the light receiving unit does not receive the reflected light from the object even when light is projected from the object, the count value of the number of consecutive non-sensing cycles by the counting means reaches the second threshold value. The determination means is characterized in that it is determined as non-sensing confirmation.

  Furthermore, an invention according to claim 4 of the present application (hereinafter referred to as a fourth invention) is characterized in that, in the third invention, the second threshold value is equal to the first threshold value.

  Furthermore, the invention according to claim 5 of the present application (hereinafter referred to as the fifth invention) is the light receiving device according to any one of the first to fourth inventions, immediately before each light projection from the light projecting unit. The apparatus further comprises a check mode for checking the presence or absence of light reception by the unit.

  Furthermore, an invention according to claim 6 of the present application (hereinafter referred to as a sixth invention) is the check according to the fifth invention, wherein the number of consecutive non-sensing cycles is counted by the counting means. In the mode, when the light receiving unit receives light immediately before the light projecting from the light projecting unit, the count value of the continuous number of the non-sensing cycles by the counting unit is counted up. It is.

  Furthermore, the invention according to claim 7 of the present application (hereinafter referred to as the seventh invention), in the fifth or sixth invention, in the case where the number of consecutive sensing cycles is counted by the counting means, In the check mode, when the light receiving unit receives light immediately before the light projecting from the light projecting unit, the count value of the continuous number of the sensing cycles by the counting unit is counted down. It is.

  Furthermore, an invention according to claim 8 of the present application (hereinafter referred to as a seventh invention) is the discharge nozzle for discharging a predetermined fluid in any one of the first to seventh inventions. It is a finger sensor that senses a finger that is presented below.

  According to the first invention of the present application, when the standby mode is switched to the sensing mode, the count value of the number of consecutive sensing cycles in which the light receiving unit emits light reflected from the object and receives light reflected from the object is calculated. Until the first threshold value is reached, the determination of sensing is not determined. That is, it is possible to improve the reliability of the sensing determination when sensing that the object is within the sensor sensing range. Further, even when there is an object near the boundary of the sensor detection range, it is possible to effectively suppress the occurrence of false detection of “there is an object” even though the object is not actually within the detection range. It is possible to improve the stability of the sensing state of the sensor when there is an object near the boundary of the sensing range.

  In addition, according to the second invention of the present application, basically, the same operational effects as the first invention can be achieved. In particular, when it is determined that no sensing is performed before the count value of the continuous number of sensing cycles reaches the first threshold in the sensing mode, the count value of the continuous number of sensing cycles by the counting unit is reset, and Since the detection mode is switched to the standby mode, the occurrence of the false detection can be more effectively suppressed.

  Furthermore, according to the third invention of the present application, basically the same operational effects as those of the first or second invention can be obtained. In particular, when it is determined that the sensing is confirmed in the sensing mode, and a non-sensing state is detected in which the light receiving unit does not receive the reflected light from the object even if light is projected from the light projecting unit, the non-sensing by the counting unit is detected. Until the count value of the continuous number of cycles reaches the second threshold value, it is not determined that the non-sense is confirmed. That is, it is possible to improve the reliability of the non-sensing determination when the non-sensing state is detected after the sensing is determined in the sensing mode. Further, even when there is an object near the boundary of the sensor detection range, it is possible to effectively suppress the occurrence of false detection of “no object” even though the object is actually within the detection range. Therefore, it is possible to further improve the stability of the sensing state of the sensor when there is an object near the boundary of the sensor sensing range without increasing the number of sensing sensors.

  Furthermore, according to the fourth invention of the present application, basically the same operational effects as the third invention can be obtained. In particular, since the threshold value is the same between the determination of sensing determination and the determination of non-sensing determination, the reliability of determination of sensing determination and determination of non-sensing determination can be set to be equal.

  Furthermore, according to the fifth invention of the present application, basically, the same effect as any one of the first to fourth inventions can be obtained. In particular, the presence or absence of light reception by the light receiving unit can be checked immediately before each light projection from the light projecting unit, and the presence or absence of misdetection due to the light receiving unit receiving disturbance light can be reliably checked. Can do. That is, it is possible to take a countermeasure against false detection due to disturbance light such as a fluorescent lamp and sunlight with an inexpensive and simple configuration without adding a special structure.

  Still further, according to the sixth invention of the present application, basically, the same effect as that of the fifth invention can be obtained. In particular, when the number of consecutive non-sensing cycles is counted by the counting means, when the light receiving unit receives light immediately before the light projecting from the light projecting unit in the check mode, the counting is performed. Since the count value of the number of consecutive non-sensing cycles by the means is counted up, when a non-sensing state is detected after it is determined that sensing is confirmed in the sensing mode, the object is actually within the sensing range. It is possible to more effectively suppress the false detection of “there is an object” even though there is no.

  Still further, according to the seventh invention of the present application, basically, the same operational effects as those of the fifth or sixth invention can be achieved. In particular, when the number of consecutive sensing cycles is counted by the counting unit, when the light receiving unit receives light immediately before the light projecting from the light projecting unit in the check mode, the counting unit Since the count value of the continuous number of times of the sensing cycle is counted down, when it is determined that the sensing is confirmed in the sensing mode, “there is an object” even though the object is not actually within the sensing range. It is possible to more effectively suppress false detection.

  Still further, according to the eighth invention of the present application, basically any of the first to seventh inventions regarding a finger sensor that senses a finger that has been pushed out below a discharge nozzle that discharges a predetermined fluid. It is possible to achieve the same operational effect as that of Kaichi, and to effectively suppress the occurrence of malfunction of the fluid discharge nozzle due to erroneous detection of the finger sensor.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings, taking as an example a case where the present invention is applied to a finger sensor of a hand washing apparatus.
FIG. 1 is a schematic explanatory diagram for explaining a control device for a hand sensor of the hand washing apparatus according to the present embodiment. As shown in the figure, the finger sensor 1 includes a light projecting unit 2 that projects light such as infrared light, and the light from the light projecting unit 2 is detected by the finger sensor 1 (sensor sensing range). A light receiving unit 3 that can receive the reflected light when reflected by a user's finger M provided within the sensor sensing range, that is, when the light is received by the light receiving unit 3 In addition, it is perceived as “with fingers”. The sensor sensing range is determined by the position and distance with respect to the light projecting unit 2 and the light receiving unit 3.

  The light projecting unit 2 includes an electric circuit including a transistor 2a, a light emitting diode 2b, and a plurality of resistors 2c. In addition, the light receiving unit 3 includes a light receiving module 3a as a main part. The configurations and operations of the light projecting unit 2 and the light receiving unit 3 are the same as those conventionally known. Both the light projecting unit 2 and the light receiving unit 3 are connected to a control unit 10 capable of controlling the finger sensor 1 so as to exchange signals. The control unit 10 is configured with, for example, a microcomputer as a main part.

  Although not specifically illustrated, the control unit 10 can send and receive signals to a water solenoid valve for supplying hand wash water to a hand wash water nozzle of a hand wash device and a chemical solenoid valve for supplying chemical liquid to a chemical nozzle. And outputs a command signal to these solenoid valves according to the sensing result of the finger sensor 1. As a result, the chemical solution and the hand wash water are sequentially discharged and supplied from the chemical solution nozzle and the hand wash water nozzle toward the user's finger M that is provided within the sensor sensing range. By drawing out from the sensor sensing range, it is possible to stop the supply of the chemical solution and the hand washing water. The basic configuration and operation of such a hand-washing apparatus are the same as those conventionally known.

In the present embodiment, the operation mode of the finger sensor 1 includes a standby mode in which light is projected from the light projecting unit 2 at a first light projecting interval (for example, 300 milliseconds [msec]), and a first mode from the light projecting unit 2 to the first. A sensing mode is set in which light is projected at a second light projection interval (for example, 3 msec) shorter than the light projection interval. The light projection time is set to 1 msec, for example.
During normal times when the user's finger M is not sensed within the sensor sensing range, the finger sensor 1 operates in a standby mode with a long light projection interval. When it is sensed that the user's finger M is within the sensor sensing range during the operation in the standby mode, the mode is switched to the sensing mode in which the light projection interval is short.

  In the present embodiment, as the operation mode of the finger sensor 1, a check mode for checking whether or not the light receiving unit 3 receives light immediately before each light projection from the light projecting unit 2 is set. In this check mode, the presence or absence of light reception by the light receiving unit 3 is checked immediately before the light projection from the light projecting unit 2 (for example, 1 msec before light projection). If the light is received by the unit 3, it is determined that it is a false detection due to the reception of disturbance light. This check is performed each time there is a light projection from the light projecting unit 2 in any of the standby mode and the sensing mode.

  In this way, by checking the presence or absence of light reception by the light receiving unit 3 immediately before each light projection from the light projecting unit 2, it is possible to reliably check for the occurrence of false detection due to the light receiving unit 3 receiving disturbance light. can do. That is, countermeasures against erroneous detection due to disturbance light such as a fluorescent lamp and sunlight can be performed with a relatively inexpensive and simple configuration without requiring addition of a special structure.

Next, the schematic configuration of the control unit 10 will be described with reference to the block configuration diagram of FIG.
The control unit 10 transmits a signal between the sensor signal transmitting / receiving unit 10a that transmits and receives signals between the light projecting unit 2 and the light receiving unit 3 of the finger sensor 1 and a control unit (not shown) of the hand-washing device. And a device signal transmission / reception unit 10b for performing transmission / reception. A mode control unit 11 is connected to the sensor signal transmission / reception unit 10a to perform switching control of the operation mode (standby mode, sensing mode, check mode) of the finger sensor 1. For example, when it is detected that an object such as the user's finger M is within the sensor detection range during the standby mode, the mode control unit 11 switches to the detection mode.

  The control unit 10 receives light reflected from the light projected from the light projecting unit 2 by the object M (finger) by the light receiving unit 3, and “there is an object” within the sensor sensing range. There is provided a counting section 12 that counts (counts) the number of consecutive sensing cycles. The counting unit 12 also counts the number of consecutive non-sensing cycles in which the light receiving unit 3 does not receive the reflected light from the object M even if the light projecting unit 2 projects light.

The count unit 12 is electrically connected to a memory unit 13 that can store count values of the number of consecutive sensing cycles and non-sensing cycles. The memory unit 13 may be separately provided outside the control unit 10.
Further, the control unit 10 includes a determination unit 14 electrically connected to the mode control unit 11, the count unit 12, and the memory unit 13, and the determination unit 14 is connected to the device signal transmission / reception unit 10b. .

  In this embodiment, when the count value of the number of consecutive sensing cycles by the counting unit 12 reaches a predetermined first threshold value (for example, 20 times) when switching from the standby mode to the sensing mode, the determination is performed. The unit 14 determines that “sensing is confirmed”. On the other hand, when the continuation of the sensing cycle is interrupted until the first threshold value is reached, the determination unit 14 determines that it is “non-sensing”. The first threshold value is stored in the memory unit 13.

  Accordingly, when the standby mode is switched to the sensing mode, the count value of the continuous number of sensing cycles in which the light projecting unit 2 projects light and the light reflected by the object M is received by the light receiving unit 3 reaches the first threshold value. Until then, it is not determined as “sensed confirmation”. That is, it is possible to improve the reliability of the sensing determination when it is sensed that the object M is within the sensor sensing range. Further, even when there is an object near the boundary of the sensor detection range, it is possible to effectively suppress the occurrence of false detection that “there is an object” even though the object M is not actually within the sensor detection range, It is possible to improve the stability of the sensing state of the sensor when there is an object near the boundary of the sensor sensing range.

When the determination unit 14 determines “non-sensing” in the sensing mode, the count value of the continuous number of sensing cycles by the counting unit 12 is reset, and the sensing mode is set to be switched to the standby mode.
Thereby, although the object M is not actually within the sensor detection range, the occurrence of the false detection that “there is an object” can be more effectively suppressed.

  Further, after the determination unit 14 determines that the detection is confirmed in the detection mode, if a non-detection state is detected in which the light receiving unit 3 does not receive the reflected light from the object M even if light is projected from the light projecting unit 2, When the count value of the number of consecutive non-sensing cycles by the counting unit 12 reaches a second threshold value (for example, 20 times), the determining unit 14 determines “non-sensing confirmed”.

Therefore, after it is determined that the sensing is confirmed in the sensing mode, if a non-sensing state is detected in which the light receiving unit 3 does not receive the reflected light from the object M even if light is projected from the light projecting unit 2, the counting unit 12 Until the count value of the number of consecutive non-sensing cycles reaches the second threshold value, it is not determined that “no sensing is confirmed”. That is, it is possible to increase the reliability of the non-sensing determination when the non-sensing state is detected after the sensing is determined in the sensing mode.
Further, even when there is an object near the boundary of the sensor detection range, it is possible to effectively suppress the occurrence of false detection of “no object” even though the object M is actually within the sensor detection range. Therefore, it is possible to further improve the stability of the sensing state of the sensor when there is an object near the boundary of the sensor sensing range without increasing the number of sensing sensors.

  In the process in which the number of consecutive non-sensing cycles is counted by the counting unit 12, if the “sensing” state is detected before the count value reaches the second threshold value, the number of consecutive non-sensing cycles is counted. The value is reset and counting of the number of consecutive non-sensing cycles will be started again.

  In this case, since the threshold value at the time of determination of sensing (first threshold value) and the threshold value at the time of determination of non-sensing determination (second threshold value) are set equal, the determination of the determination of sensing and the reliability of the determination of non-sensing determination The sex can be made equivalent.

  As described above, when the non-sensing state of “no object” continues and the sensing state of “the object is present” (first sensing) is detected, the determination unit 14 performs “sensing confirmation”. ”, The count value of the continuous number of sensing cycles by the counting unit 12 needs to reach a first threshold value (for example, 20 times). On the other hand, when the “no object” non-sensing state (first non-sensing) is detected when the “object present” sensing state continues, the determination unit 14 performs “non-sensing confirmation”. Until the determination is made, the count value of the number of consecutive non-sensing cycles by the counting unit 12 needs to reach a second threshold value (for example, 20 times).

  FIG. 3 shows a detection confirmation process (indicated by a solid line a) from the non-sensing state to “sensing confirmation”, and a non-sensing confirmation process (indicated by a broken line b) from the sensing state to “non-sensing confirmation”. It is explanatory drawing which represented typically. As shown in this figure, in the sensing confirmation process, the first threshold value (without interruption) is interrupted halfway from the time of detection of the first sensing state (point A1) to the “sensing confirmation” (point A2). Since the sensing cycle needs to be continuously counted for the number of times corresponding to, for example, 20 times, from the time of detection of the first sensing state (A1 point) to the “sense confirmation” (A2 point), Even if there is no interruption on the way, the width Wa (that is, the time width) of the number of cycles corresponding to the number of times of the first threshold (for example, 20 times) is required.

On the other hand, in the non-sensing confirmation process, from the time of detection of the first non-sensing state (point B1) to the "non-sensing confirmation" (point B2), there is no interruption in the middle. Since the non-sensing cycle needs to be continuously counted for the number of times corresponding to the second threshold (for example, 20 times), “non-sensing confirmation” (B2) from the time of detection of the first non-sensing state (point B1). Even if there is no interruption in the middle of the point), a cycle number width Wb (that is, a time width) corresponding to the number of times of the second threshold value (for example, 20 times) is required.
In the present embodiment, since the first and second threshold values are set to the same number of times (for example, 20 times), the widths Wa and Wb are equal to each other.

  Thus, in the sensing confirmation process and the non-sensing confirmation process, there is a kind of hysteresis corresponding to the width (Wa = Wb). When the object M is near the boundary of the sensing range, the stability of the sensing state of the finger sensor 1 is further increased. That is, the wider the width (Wa = Wb) due to the hysteresis, the more sensitive and more reliable the determination of “sensing confirmation” or “non-sensing confirmation” is. Therefore, for example, even when the object M (user's finger) near the boundary of the sensor sensing range moves slightly or when there is a noise input, “sensing confirmation” or “non-sensing confirmation” is immediately switched accordingly. There is nothing, and the reliability of the finger sensor 1 can be improved.

A specific example of the control of the finger sensor 1 as described above will be described with reference to the flowcharts of FIGS. 4 and 5.
For example, when the system is started by turning on the power of the hand-washing apparatus, first, in step # 1, the count state of the count unit 12 is determined. That is, it is determined whether the number of consecutive sensing cycles or the number of consecutive non-sensing cycles has not been counted (that is, whether the number of counts is 0). It is set (step # 2), and in the case of NO, it is set to the sensing mode (step # 3).

Next, in any of the sensing mode and the standby mode, the check mode is activated before light projection (step # 4). Then, in step # 5, based on the count state of the count unit 12 (see step # 1), it is determined whether or not there is a finger presence confirmation state (that is, a “sensing confirmation” state). If the determination result in step # 5 is NO, the number of consecutive sensing cycles is counted. First, in step # 6, it is determined whether or not there is light reception by the light receiving unit 3, and this determination is made. If the result is NO, light projection from the light projecting unit 2 is performed (light projection ON: step # 7).
In step # 8, it is determined whether or not there is no light reception by the light receiving unit 3 with respect to this light projection. If the determination result is NO (that is, light reception is present), the light projection is turned off ( After step # 9), the count value (Nk) of the continuous number of sensing cycles is counted up (Nk = Nk + 1: step # 10).

  On the other hand, if the determination result in the step # 8 is YES, that is, if the light receiving unit 3 does not receive light even though there is light projection from the light projecting unit 2, the light projection is turned off (step # 11). After that, the count of the continuous number of sensing cycles is reset, and the count value Nk of the continuous number of sensing cycles is set to zero (0) (Nk = 0: step # 12). Thereafter, the process returns to step # 1, and the subsequent steps are repeated. In this case, since the count value Nk of the continuous number of sensing cycles is set to zero (0) in step # 12, step The determination in # 1 is YES, and the standby mode is set (step # 2).

  Further, when the determination result in step # 6 is YES, that is, when the light receiving unit 3 receives light before the light projection from the light projecting unit 2 (although there is no light projection yet). Without performing the light projection by the light projecting unit 2, the count value Nk of the continuous number of sensing cycles by the counting unit 12 is counted down (Nk = Nk−1) in step # 13.

  As described above, when the number of consecutive sensing cycles is counted by the counting unit 12, when light is received by the light receiving unit 3 immediately before the light projecting from the light projecting unit 2 in the check mode, that is, disturbance light is generated. When it is considered that there is an erroneous detection, the count value Nk of the number of consecutive detection cycles by the count unit 12 is counted down. Therefore, when determining the detection in the detection mode, the user's finger is actually used. Although M is not within the sensor detection range, it is possible to more effectively suppress the occurrence of false detection of “with fingers”.

When step # 13 or step # 10 is completed, it is determined in step # 14 whether the count value Nk of the continuous number of sensing cycles has reached the first threshold value n1 (n1 = 20 in this embodiment). The When the determination result is YES, it is determined that the finger is present (sensing confirmation) (step # 15), and after the count value Nk is reset (Nk = 0: step # 16), the process proceeds to step # 3. Return and the subsequent steps are repeated.
If the determination result in step # 14 is NO, that is, if the count value Nk of the number of consecutive sensing cycles has not reached the first threshold value n1, the process returns to step # 1, and the subsequent steps Is repeated.

On the other hand, if the determination result in step # 5 is YES, that is, if it is determined that there is a finger (sensing confirmation) after the start of the check mode and before light projection, the number of consecutive non-sensing cycles is counted. First, in step # 17, it is determined whether or not there is light reception by the light receiving unit 3. If the determination result is NO, light projection from the light projecting unit 2 is performed (light projection ON: step #). 18).
In step # 19, it is determined whether or not there is light reception by the light receiving unit 3 with respect to this light projection. If the determination result is NO (that is, no light reception), the light projection is turned off ( After step # 20), the count value (Nj) of the continuous number of non-sensing cycles is counted up (Nj = Nj + 1: step # 21).

  Further, when the determination result in step # 17 is YES, that is, when the light receiving unit 3 receives light before the light projecting from the light projecting unit 2 (although there is no light projection yet). Without performing the light projection by the light projecting unit 2, in step # 21, the count value Nj of the number of consecutive non-sensing cycles by the counting unit 12 is counted up (Nj = Nj + 1).

  As described above, when the number of consecutive non-sensing cycles is counted by the counting unit 12, when light is received by the light receiving unit 3 immediately before the light projecting from the light projecting unit 2 in the check mode, that is, disturbance light. When it is considered that there has been a false detection due to, the count value Nj of the number of consecutive non-sensing cycles by the counting unit 12 is counted up, so that the non-sensing state is determined after the sensing is determined to be confirmed in the sensing mode. When it is detected, it is possible to more effectively suppress the occurrence of false detection that “the finger is present” even though the object M (user's finger) is not actually within the sensor detection range.

When step # 21 is completed, it is determined in step # 22 whether or not the count value Nj of the number of consecutive non-sensing cycles has reached the second threshold value n2 (n2 = 20 in this embodiment). When the determination result is YES, it is determined that there is no finger (non-sensing determination) (step # 23), and after the count value Nj is reset (Nj = 0: step # 24), the step # 1 is performed. Returning to, the subsequent steps are repeated.
Also, if the determination result in step # 22 is NO, that is, if the count value Nj of the number of consecutive non-sensing cycles has not reached the second threshold value n2, the process returns to step # 1 and the subsequent steps The steps are repeated.

On the other hand, when the determination result in step # 19 is NO, that is, when there is light projection from the light projecting unit 2 and the light receiving unit 3 receives light, the light projection is turned off (step # 25). The count of the continuous number of non-sensing cycles is reset, and the count value Nj is set to zero (0) (Nj = 0: step # 26). Thereafter, the process returns to step # 3, and the subsequent steps are repeated.
In addition, this system is complete | finished when the power supply of a hand-washing apparatus is turned off, for example.

  As described above, according to the present embodiment, when the standby mode is switched to the sensing mode, it is determined that the sensing is confirmed until the count value Nk of the continuous number of sensing cycles reaches the first threshold value n1. There is nothing. That is, it is possible to improve the reliability of the sensing determination when it is sensed that the object M is within the sensor sensing range. Further, even when the object M is in the vicinity of the boundary of the sensor detection range, it is possible to effectively suppress the occurrence of erroneous detection that “there is an object” even though the object is not actually within the detection range.

Furthermore, after the determination of sensing is determined in the sensing mode, when a non-sensing state is detected, it is determined that sensing is not confirmed until the count value Nj of the number of consecutive non-sensing cycles reaches the second threshold value n2. There is no. That is, it is possible to improve the reliability of the non-sensing determination when the non-sensing state is detected after the sensing is determined in the sensing mode. Further, even when there is an object near the boundary of the sensor detection range, it is possible to effectively suppress the occurrence of false detection of “no object” even though the object is actually within the sensor detection range.
That is, even when the object M (user's finger) near the boundary of the sensor detection range moves slightly or when there is a noise input, “sensing confirmation” or “non-sensing confirmation” is immediately switched accordingly. Absent. Therefore, without increasing the number of sensing sensors, the stability of the sensing state of the sensors can be further improved and the reliability of the finger sensor 1 can be improved.

Although the above description is about the case of controlling the finger sensor of the automatic hand washing apparatus, the present invention is not limited to such a case. For example, the finger sensor of the automatic fluid dispenser is used. The present invention can be effectively applied to control of various other object detection sensors.
Thus, it goes without saying that the present invention is not limited to the above-described embodiments, and various improvements and design changes can be made without departing from the scope of the invention.

  The present invention provides an object detection sensor that senses that an object is within the sensor sensing range by reflecting light from the light projecting unit from an object within a predetermined sensor sensing range and being received by a light receiving unit. In this control device, it is possible to prevent erroneous detection due to ambient light, and to stabilize the detection state of the sensor when there is an object near the boundary of the detection range of the detection sensor without increasing the number of detection sensors. For example, an automatic hand-washing device or dispenser that can automatically discharge and supply fluid by sensing a user's use operation such as an operation of a user's finger pointing below a discharge nozzle with a sensor. It can be suitably used as a control device for the provided finger sensor.

It is typical explanatory drawing for demonstrating the control apparatus of the finger sensor which concerns on embodiment of this invention. It is a block block diagram for demonstrating schematic structure of the control unit of the said finger sensor. It is explanatory drawing which represented typically the sensing confirmation process of the said finger sensor, and a non-sensing confirmation process. It is a part of flowchart for demonstrating the specific example of control of the said finger sensor. It is a part of flowchart for demonstrating the specific example of control of the said finger sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Finger sensor 2 ... Light projection part 3 ... Light-receiving part 10 ... Control unit 11 ... Mode control part 12 ... Count part 13 ... Memory part 14 ... Determination part M ... User's finger n1 ... 1st threshold value n2 ... 2nd threshold value Nj ... Count value of the number of consecutive non-sense cycles Nk ... Count value of the number of consecutive non-sense cycles

Claims (8)

A control device for an object detection sensor that senses that an object is within the sensing range by reflecting light from a light projecting unit from an object within a predetermined sensing range and being received by a light receiving unit. ,
A standby mode in which light is projected from the light projecting unit at a first light projecting interval; and a sensing mode in which light is projected at a second light projecting interval shorter than the first light projecting interval. Mode control means for switching to a sensing mode when sensed to be within the sensing range;
The number of consecutive sensing cycles in which the light receiving unit projects light from the light projecting unit and receives light reflected from the object, and the light receiving unit does not receive light reflected from the object even if light is projected from the light projecting unit. A counting means for counting the number of consecutive non-sensing cycles,
When the count mode is switched from the standby mode to the sensing mode, if the count value of the continuous number of sensing cycles by the counting means reaches a first threshold value, it is determined that the sensing is confirmed, and the sensing is performed until the first threshold value is reached. Determination means for determining non-sensing when the cycle is interrupted;
An apparatus for controlling an object detection sensor comprising:   In the sensing mode, when the determination unit determines that the sensing cycle is not sensed before the count value of the number of consecutive sensing cycles reaches the first threshold value, the count value of the number of consecutive sensing cycles by the counting unit is reset. 2. The control device for an object detection sensor according to claim 1, wherein the detection mode is switched to the standby mode.   In the detection mode, after the determination means determines that the detection is confirmed, the count means is detected when a non-sensing state is detected in which the light receiving section does not receive the reflected light from the object even if light is projected from the light projecting section. 3. The control device for an object detection sensor according to claim 1, wherein when the count value of the continuous number of the non-sensing cycles by the first threshold value reaches a second threshold, the determination unit determines that the non-sensing is confirmed.   4. The control device for an object detection sensor according to claim 3, wherein the second threshold value is equal to the first threshold value.   5. The object detection sensor according to claim 1, further comprising a check mode for checking whether light is received by the light receiving unit immediately before each light projection from the light projecting unit. Control device.   In the case where the continuous number of the non-sensing cycles is counted by the counting unit, when the light receiving unit receives light immediately before the light projecting from the light projecting unit in the check mode, the counting unit 6. The control device for an object detection sensor according to claim 5, wherein a count value of the continuous number of the non-sensing cycles is counted up.   In the case where the continuous number of the sensing cycles is counted by the counting unit, when light is received by the light receiving unit immediately before the light projecting from the light projecting unit in the check mode, the counting unit performs the The apparatus according to claim 5 or 6, wherein a count value of the number of consecutive sensing cycles is counted down. The object detection sensor according to any one of claims 1 to 7, wherein the object detection sensor is a finger sensor that detects a finger that is provided below a discharge nozzle that discharges a predetermined fluid. Control device.

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