Optical touchless sensor

Abstract

To provide an optical touchless sensor that operates normally even in an environment where background light changes suddenly at short intervals. [Solution] The control unit measures a non-emission level, which is the light reception level of the light receiving element when the light emitting element is not emitting light, and an emission level, which is the light reception level of the light receiving element when the light emitting element is emitting light. The control unit determines the presence or absence of a manipulation object within the detection range according to a detection level that indicates the difference between the non-emission level and the emission level. The shift in measurement timing between the non-emission level and the emission level is set to a time width that allows the position of the moving object in the external environment of the moving object to be considered to be the same, even if the moving object equipped with the optical touchless sensor is moving at a set speed.

Description

[Technical field]

[0001] The present disclosure relates to optical touchless sensors. [Background technology]

[0002] The following Patent Document 1 describes a technology for removing the effects of background light according to the external environment by processing a detection signal from a light receiving element in a first detection state in which the light emitting element is emitting light and a detection signal from the light receiving element in a second detection state in which the light emitting element is not emitting light in an optical touchless sensor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6659237 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional technology, the optical touchless sensor is processed by comparing signals with different detection timings in units of several hundred milliseconds, focusing on the characteristics of the movement of the detected object, such as the hand of a person operating the optical touchless sensor. For this reason, for example, in a car traveling at 100 km / h under direct sunlight on a road with trees and buildings in the shade, there is a problem that it is difficult to operate the optical touchless sensor accurately. That is, in the above-mentioned environment, the background light changes suddenly in a short time, so in the conventional technology, signals detected in different external environments are compared, and the background light component cannot be removed, resulting in deterioration of the judgment accuracy. In addition, in the above-mentioned environment, the light-emitting element needs to emit light with an intensity that is comparable to that of sunlight, and if it continues to emit light with such an intensity, there is also a problem that the light-emitting element will break down due to heat loss.

[0005] One aspect of the present disclosure provides an optical touchless sensor that operates normally even in an environment where the background light changes rapidly over a short interval. [Means for solving the problem]

[0006] One aspect of the present disclosure is an optical touchless sensor including a sensor unit and a controller. The sensor unit includes a light-emitting element that emits light in a determined irradiation direction, and a light-receiving element that receives light coming from the irradiation direction. The controller measures a non-emission level, which is a light reception level of the light-receiving element when the light-emitting element does not emit light, and an emission level, which is a light reception level of the light-receiving element when the light-emitting element emits light. The controller is also configured to determine the presence or absence of an operating object within the detection range according to a detection level that represents a difference between the non-emission level and the emission level. The measurement timing difference between the non-emission level and the emission level is set to a time width that allows the position of a moving object in the external environment of the moving object to be considered to be the same even if the moving object equipped with the optical touchless sensor moves at a set speed.

[0007] According to this configuration, the non-light-emitting level and the light-emitting level are measured under a condition in which the position of the moving object in the external environment can be considered to be the same, i.e., under the same background light, thereby improving the calculation accuracy of the detection level and, in turn, the detection accuracy of the presence or absence of a touchless operation by the operating object. [Brief description of the drawings]

[0008] [Figure 1] 1 is a block diagram showing a functional configuration of an optical touchless sensor according to a first embodiment; [Diagram 2] 3 is an explanatory diagram showing the appearance of a sensor unit and a partially enlarged cross section thereof; FIG. [Diagram 3] 4 is an explanatory diagram showing the size and usage of the sensor unit. FIG. [Figure 4] 13 is a flowchart of a measurement process. [Diagram 5] FIG. 4 is a timing diagram showing the overall operation of the optical touchless sensor. [Figure 6] 13 is a flowchart of an output process. [Figure 7] FIG. 11 is a timing diagram illustrating an output by the output process. [Figure 8] FIG. 2 is an explanatory diagram showing the principle of a diagnostic process. [Figure 9] 13 is a flowchart of a diagnosis process. [Figure 10] FIG. 11 is an explanatory diagram showing the correspondence between measurement values ​​and diagnosis results. [Figure 11] FIG. 11 is a block diagram showing a functional configuration of an optical touchless sensor according to a second embodiment. [Figure 12] FIG. 2 is an explanatory diagram showing the appearance of a sensor group. [Figure 13] 1A to 1C are explanatory diagrams illustrating an example of a usage state of the optical touchless sensor. [Figure 14] 13 is a flowchart of an output process. [Figure 15] 4 is a graph illustrating the detection levels of each sensor unit constituting a sensor group. [Figure 16] 11 is a timing diagram illustrating an example of an output when hysteresis is provided to a threshold value for determining whether or not an operation is performed on the sensor unit from the detection level. FIG. [Figure 17] 11 is an explanatory diagram showing another configuration example of the element portion. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. [1. First embodiment] [1-1. Configuration] An optical touchless sensor 1 shown in FIG. 1 detects an operation by a fingertip when the fingertip is brought close to an operation panel, without touching the operation panel, and provides a detection signal to a control target 100.

[0010] The optical touchless sensor 1 includes a sensor unit 2 and a control unit 3. The optical touchless sensor 1 may also include an output function setting unit 4, an external display unit 5, and a proximity sensor 6. The sensor unit 2 includes an element section 21 and a unit display section 22 .

[0011] As shown in Fig. 2, the element section 21 includes a light emitting element 211 and a light receiving element 212. For example, an infrared emitting diode (hereinafter, IRLED) is used as the light emitting element 211. For example, a photodiode whose light receiving range includes the frequency band of the light (hereinafter, irradiated light) irradiated by the light emitting element 211 is used as the light receiving element 212. The light receiving element 212 is not limited to a photodiode, and a phototransistor, a CdS cell, or the like may be used. For example, near-infrared light having a wavelength of about 800 nm to 1000 nm is used as the irradiated light, but it is not necessarily infrared.

[0012] The sensor unit 2 includes a housing 23 and an operation panel 24. The housing 23 is formed of a material that does not transmit the irradiated light. The housing 23 includes two storage spaces having openings for passing the irradiated light on one surface (hereinafter, the housing top surface) 23a of the housing 23, which serves as the light-emitting surface and the light-receiving surface. The light-emitting element 211 and the light-receiving element 212 are stored in the two storage spaces individually. That is, the light-emitting element 211 irradiates light with the direction from the bottom of the storage space toward the opening as the irradiation direction. The light-receiving element 212 receives the light arriving from the irradiation direction.

[0013] The operation panel 24 is a plate-like member made of a material that transmits the irradiated light. The operation panel 24 covers the housing top surface 23a, and is attached so that the light-emitting element 211 and the light-receiving element 212 housed in the housing 23 are located near the center of the operation panel 24. The operation panel 24 may be printed with letters, numbers, figures, etc. indicating functions, etc. associated with the sensor unit 2. For printing, ink or paint having a property of transmitting infrared light, which is the irradiated light, may be used. The operation panel 24 may also be formed by processing an acrylic plate or the like that is colored, such as black, and has a property of transmitting infrared light, which is the irradiated light.

[0014] 3, the two storage spaces provided in the housing 23 are formed so that the width W from end to end of the two openings is narrower than the width of an average adult's finger. In other words, the two storage spaces are configured so that when a fingertip is brought into contact with the housing top surface 23a, the fingertip can cover the entire two openings, thereby preventing background light from entering the element unit 21.

[0015] The light emission intensity of the light emitting element 211 is set so that the light emitting level is greater than the non-light emitting level when an operating object such as a fingertip is present within the detection range of the sensor unit 2. The detection range is a range in which a non-contact switch operation is detected on the sensor unit 2. Hereinafter, the maximum distance in the detection range is referred to as the detection upper limit distance L. The non-light emitting level is a light receiving level detected by the light receiving element 212 when the light emitting element 211 is not emitting light, and is also referred to as the background light level. The light emitting level is a light receiving level detected by the light receiving element 212 when the light emitting element 211 is caused to emit light. The light emitting element 211 irradiates irradiation light of an intensity according to the amplitude of the drive signal for a period according to the pulse width of the drive signal in accordance with the drive signal from the control unit 3.

[0016] The light receiving element 212 has a directivity set so that when the fingertip is located at the detection upper limit distance L from the upper surface 23a of the housing, the entire effective surface of the light receiving beam is blocked by the finger, that is, so that background light reaching the light receiving element 212 is suppressed. The effective surface of the light receiving beam means, for example, a range from the direction with the best light receiving sensitivity to the direction where the light receiving sensitivity is 3 dB lower. The light receiving element 212 receives reflected light based on the light irradiated from the light emitting element 211 and background light according to the environment. The light receiving signal from the light receiving element 212 is level-adjusted, then AD-converted and input to the control unit 3. The level adjustment of the light receiving signal may be amplification or attenuation. The light receiving signal does not necessarily need to be level-adjusted, and may be AD-converted as it is.

[0017] Here, the non-emission level detected when the fingertip is positioned at the detection upper limit distance L from the housing top surface 23a is defined as the reference background level. Also, the emission level detected when the fingertip is positioned at the detection upper limit distance L is defined as the reference reflected light level. The light-emitting element 211 is an element having a characteristic capable of emitting light with an intensity such that the reference reflected light level is equal to or greater than the reference background light level.

[0018] The background light is about 500 Lx indoors on a clear day, about 10,000 Lx in the shade on a clear day, and may reach 100,000 Lx in the sunlight on a clear day (i.e., direct sunlight). In other words, the background light varies greatly depending on the weather, time, location, etc., and particularly when used while moving in a vehicle, the background light will repeatedly vary greatly in a short period of time. However, as described above, when a fingertip is located within the detection range, direct sunlight will not be incident on the element unit 21 from the front due to the relative position between the fingertip and the element unit 21. For example, if the maximum value of direct sunlight incident from the front is 120,000 Lx, and even if a range of up to 30° from the front is blocked by the fingertip, the direct sunlight will be incident at about 100,000 Lx. Even in an environment where such background light is incident, the optical touchless sensor 1 is required to operate normally.

[0019] Returning to FIG. 2, the unit display section 22 includes a light-emitting element arranged to irradiate visible light onto the operation panel 24. The light-emitting element is not particularly limited, and for example, a light-emitting diode, an EL element, or the like can be used. The visible light incident on the operation panel 24 from the unit display section 22 is scattered within the operation panel 24, causing all or a part of the operation panel 24 to emit visible light. The unit display section 22 may be configured to be capable of displaying in a plurality of display modes, such as displaying in a plurality of display colors or blinking in a plurality of patterns, according to an instruction from the control section 3.

[0020] Returning to Fig. 1, the output function setting unit 4 instructs the control unit 3 in what format (hereinafter, switch type) the detection result of the sensor unit 2 is to be output. The output function setting unit 4 may be a physical switch, or may be a terminal device having a function for setting the output function by an operation on a screen, etc. The switch type may include, for example, momentary, alternate, etc.

[0021] The external display unit 5 is a display device provided separately from the sensor unit 2, and includes a display, a lamp, etc. The external display unit 5 may be a display device provided in a device to be controlled 100, or a display device provided in a terminal device to which the optical touchless sensor 1 is connected.

[0022] The proximity sensor 6 outputs an activation signal to the control unit 3 while detecting the intrusion of an object such as a person within a predetermined range (for example, a radius of 1 m) from the sensor unit 2. However, the proximity sensor 6 may be omitted.

[0023] The control unit 3 is an electronic control device mainly composed of a microcomputer including a CPU 35, a ROM 36, a RAM 37, etc. Various functions of the microcomputer are realized by the CPU 35 executing a program stored in a non-transitive substantial recording medium. In this example, the ROM 36 corresponds to the non-transitive substantial recording medium storing the program. Furthermore, the execution of this program executes a method corresponding to the program. Note that some or all of the functions executed by the CPU 35 may be configured as hardware using one or more ICs, etc. Also, the number of microcomputers constituting the control unit 3 may be one or more. The ROM 36 may include a non-volatile memory such as an EPROM whose stored contents can be rewritten. The EEPROM may be configured to write the settings made by the output function setting unit 4. In this case, the control unit 3 may refer to the settings written in the EEPROM when executing the process and operate according to the settings.

[0024] The control unit 3 includes, in terms of functions, a measurement unit 31 , an operation output unit 32 , and a diagnosis unit 33 . The measurement section 31 measures the non-emission level and the emission level using the element section 21, and detects the presence or absence of an operation on the operation panel 24 of the sensor unit 2 from the measurement result.

[0025] The operation output unit 32 generates a switch output SW of a pattern corresponding to the switch type according to the switch type set by the output function setting unit 4, and outputs the switch output SW to the control target 100. The operation output unit 32 may have a function of displaying the operating state and setting state of the optical touchless sensor 1 on the unit display unit 22 or the external display unit 5, based on signals handled by the measurement unit 31 and the operation output unit 32.

[0026] The diagnosis section 33 has a function of detecting an abnormality in the element section 21 . [1-2. Processing] [1-2-1. Measurement processing] The measurement process executed by the control unit 3 to realize the function of the measurement unit 31 will be described with reference to the flowchart of FIG.

[0027] The measurement process is repeatedly executed while the control unit 3 is activated. If the optical touchless sensor 1 includes the proximity sensor 6, the measurement process may be repeatedly executed only while an activation signal is being input from the proximity sensor 6, that is, only while the sensor unit 2 detects an object that has entered a predetermined range.

[0028] In S110, the measurement unit 31 outputs an instruction to turn off the light-emitting element 211, and resets the status ST, which indicates the state of the operation on the operation panel, to an initial value of 0. In S120, the measurement unit 31 determines whether it is time to measure, and if it is time to measure, the process proceeds to S130, and if it is not time to measure, the process waits by repeating the same step. The measurement timing may be a fixed cycle or may be a timing when a measurement instruction is input from the outside by some method.

[0029] In S130, the measurement unit 31 measures the non-light emitting level. That is, the measurement unit 31 measures the light receiving level of the light receiving element 212 while the light emitting element 211 is maintained in the non-light emitting state. In S140, the measurement unit 31 measures the light emitting level. That is, the measurement unit 31 measures the light receiving level of the light receiving element 212 with the light emitting element 211 in the light emitting state.

[0030] The measurement period of the non-light emitting level and the measurement period of the light emitting level are both set to the same length Tw, for example, set to about Tw=0.1 to 100 μs. In addition, in measuring the light emitting level, the light emitting element 211 continues to emit light for a light emitting time Tp from the start of the measurement period Tw. In other words, the light emitting element 211 irradiates pulsed light with a pulse width set to Tp.

[0031] Specifically, the light emission time Tp is set so that when the light emitting element 211 is caused to emit light at a pulse intensity that provides a reference reflection level, the light emission interval of the light emitting element 211 (i.e., the measurement period of the light emission level) is also taken into consideration, so that the heat loss in the light emitting element 211 due to the irradiated light is equal to or less than the allowable value of the light emitting element 211. The light emission time Tp is set to, for example, about 50 μs.

[0032] By measuring the light-on level following the non-light-on level, the measurement timing difference between the non-light-on level and the light-on level becomes the same length as the measurement period Tw, as shown in the lower part of FIG.

[0033] Moreover, assuming that the optical touchless sensor 1 is mounted on a moving object such as a vehicle, the measurement period (i.e., the measurement timing deviation) Tw is set to a time or less that can be considered to have no change in the position of the moving object in the external environment even if the moving object moves during the measurement period Tw. Note that since the movement of the moving object is faster than the movement of a finger, by setting the measurement period Tw as described above, the position of the fingertip operating on the operation panel 24 can also be considered to have no change.

[0034] Here, if the moving distance of the moving object during the measurement period Tw is, for example, 1 / 2 the width of the finger or less, preferably 1 mm or less, more preferably 0.1 mm or less, it is considered that there is no change in the relative position. If the set speed of the vehicle is 100 km / h, 100 km / h is converted to 27.8 μm / μs. In this case, if the measurement period Tw is set to 36 μs or less, the moving distance of the moving object during that time will be 1 mm or less. From this, if Tw<100 μS, it can be considered that there is no change in the position of the moving object in the external environment. In other words, it is possible to measure the non-emission level and the emission level under the condition that the position of the optical touchless sensor 1 relative to the external environment and the position of the operating fingertip relative to the sensor unit 2 can be considered to be the same.

[0035] In S150, the measurement unit 31 determines whether the non-emission level measured in S130 is within the allowable range, and if it is within the allowable range, the process proceeds to S170, and if it is outside the allowable range, the process proceeds to S160. The light receiving signal from the light receiving element 212 is amplified, AD converted, and then input to the control unit 3. Therefore, the measurement unit 31 determines that the amplified signal is outside the allowable range when it is saturated or below the lower limit level.

[0036] In S160, the measurement unit 31 adjusts the sensitivity of the amplifier circuit so that the amplified light receiving level falls within an allowable range, and the process returns to S120. In S170, the measurement unit 31 calculates the detection level LV based on the non-flash level measured in S130 and the flash level measured in S140. The detection level LV is calculated, for example, by subtracting the non-flash level from the flash level.

[0037] In S180, the measurement unit 31 determines whether the detection level LV calculated in S170 is greater than a tentative selection threshold THa, and if LV>THa, the process proceeds to S190, and if LV≦THa, the process proceeds to S200. The tentative selection threshold THa is set to a value that allows determination of whether the detection level LV has a significant level greater than the noise level, for example, according to the noise level included in the output from the light receiving element 212.

[0038] In S190, the measurement unit 31 performs a provisional selection display by the unit display unit 22, and the process proceeds to S200. The provisional selection display is a display for informing the operator that the detection level LV does not reach the level at which it is determined that an operation has been performed on the operation panel 24, but that if the operator brings a finger or the like closer and the detection level LV increases, it will be determined that an operation has been performed.

[0039] In S200, the measurement unit 31 determines whether the detection level LV is greater than the selection threshold THb, and if LV>THb, the process proceeds to S210, and if LV≦THb, the process proceeds to S230. The selection threshold THb is set to a value greater than the provisional selection threshold THa (i.e., THb>THa).

[0040] In S210, the measurement unit 31 sets the status ST to 1, which indicates that an operation on the operation panel 24 has been performed. In S220, the measurement section 31 switches the provisional selection display by the unit display section 22 to a selection display, and returns the process to S120. The selection display may be displayed in a different manner on the unit display section 22 from the provisional selection display, for example by using a different display color.

[0041] In S230, the measurement unit 31 sets the status ST to 0, which indicates that no operation has been performed on the operation panel, and returns the process to S120. Here, the operation of each unit according to the measurement process will be described with reference to the timing diagram of FIG.

[0042] As shown in Fig. 5, the light emitting element 211 is driven to emit pulsed light. Although Fig. 5 shows a case where light is emitted periodically, it is not necessarily required that light be emitted periodically. When the optical touchless sensor 1 is mounted on a vehicle and used while the vehicle is moving, the background light repeatedly increases and decreases in a short period of time according to changes in the external environment in which the vehicle is traveling. When the vehicle is traveling in direct sunlight, the level of background light increases. The reflected light shown in Figure 5 is the reflected light from a fingertip within the detection range, excluding the background light.

[0043] That is, when the non-emission level is measured, the value of the background light is sampled, and when the emission level is measured, the value obtained by adding the background light and the reflected light is sampled. The non-emission level and the emission level are sampled at timings that are offset by the measurement period Tw. Moreover, the measurement period Tw is set so that the background light situation (i.e., the position of the sensor unit 2 relative to the external environment) and the reflected light situation (the position of the operating fingertip relative to the sensor unit 2) are considered to be unchanged.

[0044] Therefore, the detection level LV, which is the difference between the background light level and the reflected light level, represents the level of only the reflected light with the influence of the background light removed. This detection level LV is the threshold value TH b If the above is the case, a determination result is obtained that an operation has been performed on the operation panel 24 of the sensor unit 2, and the status ST is set in accordance with the determination result.

[0045] [1-2-2. Output processing] The output process executed by the control unit 3 to realize the function of the operation output unit 32 will be described with reference to the flowchart of FIG.

[0046] The output process is executed every time the status ST is set in S190 or S200 of the measurement process. In S310, the operation output unit 32 determines whether or not the switch type designated by the output function setting unit 4 is momentary. If the operation output unit 32 determines that the switch type designated is momentary, the process proceeds to S320, and if the operation output unit 32 determines that the switch type is not momentary (i.e., alternate), the process proceeds to S350.

[0047] In S320, the operation output unit 32 determines whether the value of the status ST is 1 or not, and if ST=1, the process proceeds to S330, and if ST=0, the process proceeds to S340. In S330, the operation output unit 32 sets the switch output SW to a value representing ON, and ends the process.

[0048] In S340, the operation output unit 32 sets the switch output SW to a value representing OFF, and ends the process. In S350, the operation output unit 32 determines whether the value of status ST has changed from 0 to 1, and if it has changed from 0 to 1, proceeds to S360; otherwise, that is, if the value of status ST has not changed or has changed from 1 to 0, the processing ends.

[0049] In S360, the operation output unit 32 inverts the on / off state of the switch output SW, and ends the process. As shown in Figure 7, in the case of momentary, the status ST is output as is as the switch output SW. In the case of alternate, the on / off state of the switch output SW is inverted every time the status ST changes from 0 to 1.

[0050] Here, only momentary and alternate have been described as switch types realized by the operation output unit 32, but the present invention is not limited to these, and any switch type, such as "N / O", "N / C", "multi-pole", and "multi-throw", may be realized. "N / O" and "N / C" differ in which output is given when the switch is turned on or off in the case of momentary, and "N / O" represents a type in which the switch output SW is off when no switch operation is being performed (i.e., ST=0). "N / C" represents a type in which the switch output SW is on when no switch operation is being performed (ST=0). "Multi-pole" represents a switch that controls multiple circuits at the same time, and "multi-throw" represents a switch that controls multiple connection paths.

[0051] [1-2-3. Diagnostic processing] A diagnosis process for diagnosing the state of the element portion 21 will be described. In the diagnostic process, the non-emission level and the emission level are measured in a state where no operating object such as a fingertip is present within the detection range.

[0052] 8, a part of the light emitted from the light emitting element 211 is repeatedly reflected on the boundary surface of the operation panel 24, propagates inside the operation panel 24, and is received by the light receiving element 212. In other words, the light receiving level obtained by the light emission measurement is a slightly higher value than the light receiving level obtained by the non-light emission measurement, even in a state where no reflecting object is present. In the diagnostic process, the state of the element unit 21 is diagnosed by using the non-light emission level (hereinafter, non-light emission diagnostic level) and the light emission level (hereinafter, light emission diagnostic level) stored in advance in the ROM 36 or the like as diagnostic data.

[0053] The diagnostic process executed by the control unit 3 to realize the function of the diagnostic unit 33 will be described with reference to the flowchart of FIG. The diagnostic process may be executed as part of the initialization process immediately after the controller 3 is started up, or may be executed according to an external instruction.

[0054] In S510, the diagnosis unit 33 outputs an instruction to turn off the light-emitting element 211. In S520, the diagnosis unit 33 measures the non-emission level. In S530, the diagnosis unit 33 measures the light emission level.

[0055] In S540, the diagnostic unit 33 compares the non-light emitting level and the light emitting level with the non-light emitting diagnostic level and the light emitting diagnostic level indicated in the diagnostic data to determine the presence or absence of an abnormality and the cause of the abnormality.

[0056] Specifically, as shown in pattern 1 of FIG. 10, if neither the non-light-emitting level nor the light-emitting level is detected as a significant value, it is determined that there is an abnormality due to a disconnection of the light receiving element 212 or a failure of the AD conversion circuit, etc.

[0057] As shown in pattern 2, the non-light emitting level is detected to be approximately the same as the non-light emitting diagnostic level, and if the light emitting level is not detected as a significant value, it is determined that there is a break in the light emitting element 211 or an abnormality in the command system to the light emitting element 211.

[0058] As shown in pattern 3, when the non-emission level is detected to be approximately the same as the non-emission diagnostic level and the emission level is detected to be lower than the emission diagnostic level, it is determined that the abnormality is due to deterioration of the light emitting element 211.

[0059] As shown in pattern 4, when the ratio of the non-emission level and the emission level is approximately the same as the ratio of the non-emission reference level and the emission reference level, but the level is generally lower, it is determined that the abnormality is due to deterioration of the light receiving element 212.

[0060] 9, in S550, the diagnostic unit 33 notifies a predetermined destination of the diagnostic result, and ends the process. The diagnostic result may be displayed on the external display unit 5. [1-3. Effects] According to the first embodiment described above in detail, the following effects are achieved.

[0061] (1a) Optical touchless sensor 1 measures the non-emission level and the emission level at short intervals that can be regarded as measurements in the same external environment, and determines from the measurement results whether or not there is an operating object such as a fingertip within the detection range, and further whether or not there is an operation on operation panel 24. Therefore, optical touchless sensor 1 can perform measurements with reduced influence of background light even in an environment where the intensity of background light changes significantly at high speed, and can accurately detect touchless switch operations.

[0062] (1b) In the optical touchless sensor 1, the directivity of the light receiving element 212 is set so that background light is prevented from being incident on the element unit 21 from the front when the fingertip, which is the operation object, is within the detection range. Furthermore, the level of the light irradiated by the light emitting element 211 is set so that the light emitting level (i.e., light emitting reference level) in this case is higher than the non-light emitting level (i.e., non-light emitting reference level). Therefore, the optical touchless sensor 1 can detect a touchless switch operation even in an environment such as under direct sunlight.

[0063] (1c) In the optical touchless sensor 1, the pulse width of the irradiated light (i.e., the light emission time Tp of the light emitting element 211) and the irradiation interval are set so that the heat loss of the light emitting element 211 due to the irradiated light does not exceed the allowable value of the light emitting element 211. Therefore, the optical touchless sensor 1 can be configured using the light emitting element 211 that is relatively inexpensive and consumes low power. In other words, by shortening the light emission time Tp of the light emitting element 211 to about 50 μs, the light emission of the light emitting element 211 is stopped before the temperature of the light emitting element 211 rises, so that the light emitting element 211 can emit light at 10 to 100 times the normally allowable luminance. Therefore, the optical touchless sensor 1 can operate normally even in an environment where the background light changes rapidly over a wide range of 100 to 100,000 Lx, such as a vehicle running under direct sunlight.

[0064] First of all, as described in Patent Document 1, the reflected light from the object to be detected is only about several percent of the emitted light from the light emitting element. Therefore, in a situation where very bright background light such as direct sunlight enters the light receiving element, the detection signal based on the reflected light from the object to be detected is buried in the background signal based on the background light, making it difficult to detect the object to be detected. In contrast, the optical touchless sensor 1 employs flash-like emission, which enables emission of light at 10 to 100 times the normally acceptable brightness. In other words, it is possible to realize a technology for obtaining a detection signal that is not buried in the background signal, and thus a technology for improving the detection accuracy of the object to be detected, such as a finger, without performing complex processing on the received light signal as described in Patent Document 1.

[0065] (1d) In the optical touchless sensor 1, the size of the opening for accommodating the element part 21 formed on the housing top surface 23a of the sensor unit 2 is formed to be narrower than the width of the fingertip, which is the operation object. Therefore, even if a situation occurs in which the touchless switch operation does not work well due to the influence of background light, the incidence of the background light on the element part 21 can be blocked by touching the operation panel 24 with the fingertip. The irradiated light, which is infrared light, has the property of penetrating the inside of the finger and diffusing and propagating, and is received by the light receiving element 212 via the finger, so that the switch operation of the optical touchless sensor 1 can be operated in a state in which the incidence of the background light is blocked. In other words, it is possible to prevent the optical touchless sensor 1 from becoming inoperable due to the influence of the background light. In other words, there is no need to prepare a separate touch switch for such an unexpected situation, and the device configuration can be simplified.

[0066] (1e) In the optical touchless sensor 1, when the detection level LV is greater than the temporary selection threshold THa, a temporary selection display is performed using the unit display section 22, and when the detection level LV exceeds the selection threshold THb, it is determined that an operation has been performed on the operation panel 24 and the temporary selection display is switched to a selection display. This prevents the operator from erroneously determining that an operation has been performed despite no intention of performing an operation due to the temporary selection display, or from not determining that an operation has been performed due to insufficient proximity of a detected object such as a finger even if there is an intention to perform an operation.

[0067] (1f) In the optical touchless sensor 1, the non-emission level and the emission level measured when there is no operation object within the detection range are compared with the non-emission diagnostic level and the emission diagnostic level to diagnose the state of the element unit 21. Since the diagnosis utilizes light that is transmitted through the operation panel 24 and received by the light receiving element 212, there is no need to provide special equipment for the diagnosis, and a simple diagnosis can be realized.

[0068] (1g) In the optical touchless sensor 1, a switch type can be selected via the output function setting unit 4, and an appropriate switch output SW can be provided according to the control target 100. Also, the output function setting unit 4 may be used to write the switch type to a non-volatile memory whose stored contents can be rewritten. In this case, the switch type can be set or changed at any time, such as when the optical touchless sensor 1 is manufactured or installed, and the set or changed contents can be retained, thereby improving the usability of the optical touchless sensor 1.

[0069] (1h) When the optical touchless sensor 1 uses the proximity sensor 6, it can be configured to operate only when an object is detected in the vicinity of the sensor unit 2, thereby realizing low power consumption.

[0070] [2. Second embodiment] [2-1. Differences from the first embodiment] The second embodiment has a basic configuration similar to that of the first embodiment, and therefore differences will be described below. Note that the same reference numerals as those in the first embodiment indicate the same configuration, and the preceding description will be referred to.

[0071] The above-described first embodiment includes only one sensor unit 2. In contrast, the second embodiment differs from the first embodiment in that it includes a plurality of sensor units 2 and performs a process of determining which of the plurality of sensor units 2 has been operated.

[0072] [2-2. Configuration] As shown in FIG. 11, an optical touchless sensor 1a of the second embodiment includes a sensor unit group 7 including a plurality of sensor units 2 instead of a single sensor unit 2.

[0073] The control unit 3a includes a measurement unit 31a instead of the measurement unit 31, and further includes an operation object determination unit 34. The measurement unit 31a performs measurement processing individually for all sensor units 2 belonging to the sensor unit group 7. The operation object determination unit 34 executes operation object determination processing based on the output from the measurement unit 31a. The operation object determination unit 34 outputs the measurement result of the sensor unit 2 determined to be the operation object by the operation object determination processing to the operation output unit 32.

[0074] As shown in FIG. 12, a plurality of sensor units 2 belonging to a sensor unit group 7 are arranged in close proximity to each other and are used, for example, as a switch for specifying a floor when operating an elevator. 13, by bringing a finger close to any one of the sensor units 2 belonging to the sensor unit group 7, the sensor unit 2 can be operated individually. However, if the elevator is crowded and there is a person in a position close to the sensor unit group 7, there is a possibility that the sensor units 2 may be mistakenly recognized as being operated due to reactions to various parts of the body. To avoid such a situation, an operation target determination process is executed.

[0075] [2-3. Processing] The control unit 3a will explain the operation target determination process executed to realize the function as the operation target determination unit 34 with reference to the flowchart of FIG. 14. The operation target determination process is executed periodically.

[0076] In S610, the operation target determination unit 34 acquires the latest detection level LV from all the sensor units 2 belonging to the sensor unit group 7. In S620, the operation target determination unit 34 extracts the largest maximum level LV1 and the second largest second level LV2 from the detection levels LV acquired in S610. Hereinafter, the sensor unit 2 with the maximum level LV1 is referred to as the target sensor unit, and the sensor unit 2 with the second level LV2 is referred to as the comparison sensor unit.

[0077] In S630, the operation target determination unit 34 calculates the ratio LV1 / LV2 of the maximum level LV1 to the second level LV2, and determines whether LV1 / LV2 is equal to or greater than the validity determination threshold E (for example, E = 2). If the operation target determination unit 34 determines that LV1 / LV2 ≥ E, the process proceeds to S640. If it determines that LV1 / LV2 < E, the process proceeds to S700.

[0078] In S640, the operation target determination unit 34 determines whether a temporarily selected switch (hereinafter, the temporary selection switch) is set. If the temporary selection switch is not set, the process proceeds to S650. If the temporary selection switch is set, the process proceeds to S670.

[0079] In S650, the operation target determination unit 34 determines whether the maximum level LV1 is equal to or greater than the first detection threshold TH1. If LV1 ≥ TH1, the process proceeds to S660. If LV1 < TH1, the process ends.

[0080] In S660, the operation target determination unit 34 sets the target sensor unit corresponding to the maximum level LV1 to the temporary selection switch, and performs a temporary selection display indicating that it is temporarily selected using the unit display unit 22 of the temporary selection unit, and then ends the process.

[0081] In S670, the operation target determination unit 34 determines whether the temporary selection switch is at the maximum level LV1. If the temporary selection switch is at the maximum level LV1, the process proceeds to S680. If the temporary selection switch is not at the maximum level LV1, the process proceeds to S700.

[0082] In S680, the operation target determination unit 34 determines whether the maximum level LV1 is greater than or equal to a second detection threshold TH2 that is set to a value greater than the first detection threshold TH1. If LV1 ≥ TH2, the process proceeds to S690. If LV1 < TH2, the process ends.

[0083] In S690, the operation target determination unit 34 sets the sensor unit 2 set in the temporary selection switch to the selection switch. Further, the operation target determination unit 34 uses the unit display unit 22 of the selection switch to switch from the display indicating the temporary selection to the selection display indicating that it has been selected, and notifies the operation output unit 32 that the selection switch has been set, and ends the process. Note that the temporary selection display and the selection display may have different display modes, for example, by making the display colors different.

[0084] In S700, the operation target determination unit 34 resets the settings of the temporary selection switch and the selection switch, and ends the process. [2-3. Operation Example] FIG. 15 is a graph illustrating the detection level LV obtained from each sensor unit 2 belonging to the sensor unit group 7. The plurality of sensor units 2 are identified by switch numbers 1 to 8.

[0085] In the upper part of FIG. 15, switch number 3 is the maximum level LV1 (i.e., the target sensor unit), and switch number 1 is the second level LV2 (i.e., the comparison sensor unit). Moreover, since LV1 / LV2 ≥ E, if LV1 ≥ TH1, switch number 3 is set as the temporary selection switch.

[0086] In the lower part of FIG. 15, switch number 3 is at the maximum level LV1 and switch number 2 is at the second level LV2. However, since LV1 / LV2 < E, switch number 3 is not set as the tentative selection switch.

[0087] In the previous processing cycle, if switch number 3 was set as the tentative selection switch, and the state where switch number 3 is at the maximum level LV1 and LV1 / LV2 ≥ E (however, it is not necessary for switch number 1 to be at LV2) continues, the following determination is made according to the level of LV1. That is, if LV1 ≥ TH2, it is considered that the selection condition is satisfied, and switch number 3 is set as the selection switch. If LV1 < TH2, the setting as the tentative selection switch continues. Also, if switch number 3 is not at the maximum level LV1, or if LV1 / LV2 < E, the setting as the tentative selection switch is cancelled.

[0088] [2-4. Effect] According to the second embodiment described in detail above, the effects (1a) to (1d), (1f) to (1h) of the first embodiment described above are achieved, and furthermore, the following effects are achieved.

[0089] (2a) In the optical touchless sensor 1a, when the difference between the maximum level LV1 and the second level LV2 is sufficiently large based on the output of each sensor unit 2 belonging to the sensor unit group 7, and the maximum level LV1 has a sufficient magnitude, it is recognized as a valid operation. Therefore, it is possible to suppress false detection in a situation where a plurality of sensor units 2 react simultaneously due to an approach without an operation intention to the sensor unit group 7.

[0090] (2b) In the optical touchless sensor 1a, the sensor unit 2 in which a valid operation is recognized is set as the tentative selection switch and the fact of tentative selection is displayed. When the state where a valid operation is recognized continues, it is set as the selection switch and the fact that the selection switch has been operated is displayed. Therefore, it is possible to make the operator recognize whether a correct operation is being performed, and it is possible to give the operator a sense of security.

[0091] 3. Other embodiments Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments and can be implemented in various modified forms.

[0092] (3a) In the above embodiment, an example is given of the emission intensity (i.e., pulse intensity) and emission time (i.e., pulse width) of the irradiated light. However, the emission intensity and emission time may be optimized as appropriate depending on the brightness of the measurement location, the type of control object 100, etc.

[0093] (3b) In the above embodiment, a fingertip is used as the operating object for performing switch operations, but a body part larger than a finger, such as a palm, may be used. Furthermore, any object that reflects infrared rays may be used as the operating object, regardless of a body part.

[0094] (3c) In the above embodiment, near-infrared rays having a wavelength of about 800 nm to 1000 nm are used as the irradiating light. The irradiating light is not limited to near-infrared rays, and light of various wavelengths can be used as long as it does not affect the human body.

[0095] (3d) In the above embodiment, the presence or absence of an operation of the detection level LV is determined by a single threshold value TH. For example, the threshold value may have hysteresis. As shown in FIG. 16, when the detection level LV is expressed in 10 stages, the threshold value for switching from OFF to ON is set to, for example, level 6.5, and the threshold value for switching from ON to OFF is set to, for example, 3.5. In this case, even if the detection level is unstable, a stable switch output SW can be generated.

[0096] (3e) In the above embodiment, the element unit 21 includes one light emitting element 211 and one light receiving element 212. However, as shown in FIG. 17, the element unit 21 may include one light emitting element 211 arranged at the center and multiple light receiving elements 212 arranged around the light emitting element 211. For example, the light receiving elements 212 may be arranged at four locations, above, below, left, and right, or may be arranged at a total of eight locations, including the upper right, lower right, lower left, and upper left in addition to the upper right, lower right, lower left, and upper left. In this case, the movement of the fingertip can be determined from the timing at which the fingertip is detected by each light receiving element 212. Also, instead of providing multiple light receiving elements 212, combinations of the light emitting element 211 and the light receiving element 212 may be arranged at multiple locations. In this case, the set in the center may be omitted.

[0097] (3f) Multiple functions possessed by one component in the above embodiments may be realized by multiple components, or one function possessed by one component may be realized by multiple components. Also, multiple functions possessed by multiple components may be realized by one component, or one function realized by multiple components may be realized by one component. Also, part of the configuration of the above embodiments may be omitted. Also, at least part of the configuration of the above embodiments may be added to or substituted for the configuration of another of the above embodiments.

[0098] (3g) In addition to the optical touchless sensor 1, 1a described above, the present disclosure can be realized in various forms, including a system including the optical touchless sensor 1, 1a as a component, a program for causing a computer to function as the control unit 3, 3a of the optical touchless sensor 1, 1a, and a non-transient physical recording medium such as a semiconductor memory on which this program is recorded.

[0099] [4. Technical Concepts Disclosed in This Specification] [Item 1] An optical touchless sensor, a sensor unit including a light-emitting element that emits light in a determined irradiation direction and a light-receiving element that receives light coming from the irradiation direction; a control unit configured to measure a non-emission level, which is a light reception level of the light receiving element when the light emitting element does not emit light, and an emission level, which is a light reception level of the light receiving element when the light emitting element emits light, and to determine the presence or absence of an operating object within a detection range according to a detection level that indicates a difference between the non-emission level and the emission level; Equipped with The difference in the measurement timing between the non-emission level and the emission level is set to a time width that allows the position of the moving body in the external environment of the moving body to be considered to be the same even if the moving body on which the optical touchless sensor is mounted moves at a set speed. Optical touchless sensor.

[0100] [Item 2] Item 1 is an optical touchless sensor according to the present invention, a directivity of the light receiving element is set such that a receiving light beam is blocked by the manipulation object located in the detection range; the light emission intensity of the light emitting element is set such that the light emission level is greater than the non-light emission level when the operation object is present within the detection range, and the light emission level and the non-light emission level are measured in a state where the operation object is present within the detection range. Optical touchless sensor.

[0101] [Item 3] The optical touchless sensor according to item 1 or 2, The light emitting element has a pulse width, a light emission interval, and a light emission intensity of irradiation light set so that a heat loss due to light emission is equal to or less than a tolerance of the light emitting element. Optical touchless sensor.

[0102] [Item 4] An optical touchless sensor according to any one of items 1 to 3, the sensor unit includes a housing that houses the light emitting element and the light receiving element and has an opening for passing light emitted and received by the light emitting element and the light receiving element; The opening is formed to a size such that the entire opening is covered by the operation object. Optical touchless sensor.

[0103] [Item 5] Item 4. The optical touchless sensor according to item 4, the sensor unit further includes an operation panel formed of a material that transmits light emitted and received by the light-emitting element and the light-receiving element and configured to cover the opening, a diagnostic unit configured to diagnose a state of the sensor unit based on the non-emission level and the emission level measured in a state in which the operation object is not present within the detection range. Optical touchless sensor.

[0104] [Item 6] An optical touchless sensor according to any one of items 1 to 5, The manipulation object is a fingertip of a hand. Optical touchless sensor.

[0105] [Item 7] An optical touchless sensor according to any one of items 1 to 6, a sensor unit group having a plurality of the sensor units which are individually operated, The control unit, among the sensor units belonging to the sensor unit group, defines the sensor unit with the highest detection level as a target sensor unit, and the sensor unit with the second highest detection level as a comparison sensor unit, and determines that an operation has been performed on the target sensor unit when a selection condition is met that the detection level of the target sensor unit is equal to or higher than a detection threshold and that the difference between the detection level of the target sensor unit and the detection level of the comparison sensor unit is equal to or higher than a validity determination threshold. Optical touchless sensor.

[0106] [Item 8] Item 7. The optical touchless sensor according to item 7, A unit display unit configured to display in a plurality of display modes for each of the sensor units is further provided, The control unit is configured to perform a provisional selection display, which is a display in a first manner indicating that the target sensor unit is the target sensor unit, on the unit display unit of the target sensor unit, and when the selection condition is satisfied, to perform a selection display, which is a display in a second manner different from the first manner, on the unit display unit of the target sensor unit. Optical touchless sensor. [Explanation of symbols]

[0107] 1,1a...optical touchless sensor, 2...sensor unit, 3,3a...control unit, 4...output function setting unit, 5...external display unit, 6...proximity sensor, 7...sensor unit group, 21...element unit, 22...unit display unit, 23...housing, 23a...top surface of housing, 24...operation panel, 31,31a...measurement unit, 32...operation output unit, 33...diagnosis unit, 34...operation object determination unit, 35...CPU, 36...ROM, 37...RAM, 100...control object, 211...light-emitting element, 212...light-receiving element.

Claims

1. An optical touchless sensor, a sensor unit including a light-emitting element that emits light in a determined irradiation direction and a light-receiving element that receives light coming from the irradiation direction; a control unit configured to measure a non-emission level, which is a light reception level of the light receiving element when the light emitting element does not emit light, and an emission level, which is a light reception level of the light receiving element when the light emitting element emits light, and to determine the presence or absence of an operating object within a detection range according to a detection level that indicates a difference between the non-emission level and the emission level; Equipped with The measurement timing difference between the non-emission level and the emission level was set to 0.1 to 100 μs. Optical touchless sensor.

2. 2. The optical touchless sensor according to claim 1, a directivity of the light receiving element is set such that a receiving light beam is blocked by the manipulation object located in the detection range; the light emission intensity of the light emitting element is set such that the light emission level is greater than the non-light emission level when the operation object is present within the detection range, and the light emission level and the non-light emission level are measured in a state where the operation object is present within the detection range. Optical touchless sensor.

3. 2. The optical touchless sensor according to claim 1, The light emitting element has a pulse width, a light emission interval, and a light emission intensity of irradiation light set so that a heat loss due to light emission is equal to or less than a tolerance of the light emitting element. Optical touchless sensor.

4. 2. The optical touchless sensor according to claim 1, the sensor unit includes a housing that houses the light emitting element and the light receiving element and has an opening for passing light emitted and received by the light emitting element and the light receiving element; The opening is formed to a size such that the entire opening is covered by the operation object. Optical touchless sensor.

5. 5. The optical touchless sensor according to claim 4, the sensor unit further includes an operation panel formed of a material that transmits light emitted and received by the light-emitting element and the light-receiving element and configured to cover the opening, a diagnostic unit configured to diagnose a state of the sensor unit based on the non-emission level and the emission level measured in a state in which the operation object is not present within the detection range. Optical touchless sensor.

6. 2. The optical touchless sensor according to claim 1, The manipulation object is a fingertip of a hand. Optical touchless sensor.

7. 2. The optical touchless sensor according to claim 1, a sensor unit group having a plurality of the sensor units which are individually operated, The control unit, among the sensor units belonging to the sensor unit group, defines the sensor unit with the highest detection level as a target sensor unit, and the sensor unit with the second highest detection level as a comparison sensor unit, and determines that an operation has been performed on the target sensor unit when a selection condition is met that the detection level of the target sensor unit is equal to or higher than a detection threshold and that the difference between the detection level of the target sensor unit and the detection level of the comparison sensor unit is equal to or higher than a validity determination threshold. Optical touchless sensor.

8. 8. The optical touchless sensor according to claim 7, A unit display unit configured to display in a plurality of display modes for each of the sensor units is further provided, The control unit is configured to perform a provisional selection display, which is a display in a first mode indicating that the target sensor unit is the target sensor unit, on the unit display unit of the target sensor unit, and when the selection condition is satisfied, to perform a selection display, which is a display in a second mode different from the first mode, on the unit display unit of the target sensor unit. Optical touchless sensor.

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