Optical touchless sensor

Abstract

This invention provides a light-touchless sensor that operates normally even in environments where background light changes rapidly at short intervals. [Solution] The control unit measures the non-emitting level, which is the light-receiving level at the photodetector when the light-emitting element is not emitting light, and the emitting level, which is the light-receiving level at the photodetector when the light-emitting element is emitting light. The control unit determines the presence or absence of an object being manipulated within the detection range according to the detection level, which represents the difference between the non-emitting level and the emitting level. The timing difference between the measurement of the non-emitting level and the emitting level is set to a time width such that the position of the moving body in the external environment can be considered to be the same, even if the moving body equipped with the optical touchless sensor is moving at a set speed.

Description

Technical Field

[0001] The present disclosure relates to an optical touchless sensor.

Background Art

[0002] In Patent Document 1 below, in an optical touchless sensor, by using the detection signal of a light receiving element in a first detection state in which a light emitting element emits light and the detection signal of the light receiving element in a second detection state in which the light emitting element does not emit light, and processing these signals, a technique for removing the influence of background light according to the external environment is described.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the prior art, focusing on the characteristics of the movement of a detected object such as a person's hand operating an optical touchless sensor, processing is performed to compare signals with different detection timings in units of several hundred milliseconds. For this reason, for example, in a vehicle traveling at 100 km / h on a road with sunlight, shade of roadside trees, and buildings under direct sunlight, there is a problem that it is difficult to accurately operate the optical touchless sensor. That is, in the environment as described above, since the background light changes rapidly in a short time, in the prior art, signals detected in different external environments are compared, the background light component cannot be removed, and the determination accuracy deteriorates. Also, in the environment as described above, it is necessary to emit light from the light emitting element with an intensity that is not inferior to sunlight, and if it continues to emit light with such an intensity, there is also a problem that the light emitting element fails due to heat loss.

[0005] One aspect of this disclosure is to provide an optical touchless sensor that operates normally even in environments where the background light changes rapidly at short intervals. [Means for solving the problem]

[0006] One aspect of this disclosure is an optical touchless sensor comprising a sensor unit and a control unit. The sensor unit comprises a light-emitting element that emits light in a predetermined irradiation direction and a light-receiving element that receives light arriving from the irradiation direction. The control unit measures a non-emitting level, which is the level of light received by the light-receiving element when the light-emitting element is not emitting light, and an emitting level, which is the level of light received by the light-receiving element when the light-emitting element is emitting light. The control unit is also configured to determine the presence or absence of an object being manipulated within the detection range according to a detection level that represents the difference between the non-emitting level and the emitting level. The timing difference between the measurement of the non-emitting level and the emitting level is set to a time width such that the position of the mobile body in the external environment can be considered to be the same even if the mobile body on which the optical touchless sensor is mounted is moving at a set speed.

[0007] With this configuration, the non-luminescent and luminescent levels are measured under conditions where the position of the moving object in the external environment can be considered the same, i.e., under the same background light. Therefore, the accuracy of the detection level calculation, and consequently the accuracy of detecting whether or not touchless operation is performed by the operating object, can be improved. [Brief explanation of the drawing]

[0008] [Figure 1] This is a block diagram showing the functional configuration of the optical touchless sensor according to the first embodiment. [Figure 2] This is an explanatory diagram showing the external appearance of the sensor unit and a magnified cross-section of a portion of it. [Figure 3] This is an explanatory diagram showing the size and usage of the sensor unit. [Figure 4] This is a flowchart of the measurement process. [Figure 5] This is a timing diagram showing the overall operation of the optical touchless sensor. [Figure 6] This is a flowchart of the output processing. [Figure 7] This is a timing diagram illustrating the output resulting from output processing. [Figure 8] This is an explanatory diagram illustrating the principle of the diagnostic process. [Figure 9] This is a flowchart of the diagnostic process. [Figure 10] This is an explanatory diagram showing the correspondence between measured values ​​and diagnostic results. [Figure 11] This is a block diagram showing the functional configuration of the optical touchless sensor according to the second embodiment. [Figure 12] This is an explanatory diagram showing the external appearance of the sensor group. [Figure 13] This is an explanatory diagram illustrating the usage status of an optical touchless sensor. [Figure 14] This is a flowchart of the output processing. [Figure 15] This graph illustrates the detection levels of each sensor unit that make up the sensor group. [Figure 16] This timing diagram illustrates the output when hysteresis is applied to the threshold used to determine whether or not an operation has been performed on the sensor unit based on the detection level. [Figure 17] This is an explanatory diagram showing other configuration examples of the element section. [Modes for carrying out the invention]

[0009] Embodiments of this disclosure will be described below with reference to the drawings. [1. First Embodiment] [1-1. Structure] The optical touchless sensor 1 shown in Figure 1 detects fingertip operation without touching the control panel by bringing the fingertip close to the control panel and provides a detection signal to the controlled object 100.

[0010] The optical touchless sensor 1 comprises 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 unit 21 and a unit display unit 22.

[0011] As shown in FIG. 2, the element unit 21 includes a light emitting element 211 and a light receiving element 212. For example, an infrared light emitting diode (hereinafter referred to as an IRLED) is used as the light emitting element 211. For example, a photodiode whose light receiving range includes the frequency band of the light irradiated by the light emitting element 211 (hereinafter referred to as irradiation light) 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, etc. may be used. The irradiation light uses, for example, near infrared light with a wavelength of about 800 nm to 1000 nm, but does not necessarily have to be infrared light.

[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 irradiation light. The housing 23 has two storage spaces having openings for passing the irradiation light on one surface of the housing 23 (hereinafter referred to as the upper surface of the housing) 23a that serves as a light emitting surface and a light receiving surface. The light emitting element 211 and the light receiving element 212 are individually stored in the two storage spaces. 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 coming from the irradiation direction.

[0013] The operation panel 24 is a plate-like member formed of a material that transmits the irradiation light. The operation panel 24 covers the upper surface 23a of the housing 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 characters, numbers, figures, etc. indicating functions etc. associated with the sensor unit 2. For printing, ink or paint having the property of transmitting infrared light, which is the irradiation light, may be used. Also, the operation panel 24 may be configured by processing an acrylic plate etc. that is colored, such as black, and has the property of transmitting infrared light, which is the irradiation light.

[0014] As shown in Figure 3, the two storage spaces provided in the housing 23 are formed such that the width W from end to end of the two openings is narrower than the average finger width of an adult. In other words, the two storage spaces are configured so that when the fingertips are in contact with the upper surface 23a of the housing, the fingertips can cover the entirety of the two openings, thereby preventing background light from entering the element section 21.

[0015] The light emission intensity of the light-emitting element 211 is set such that the emission level is greater than the non-emission level when an object such as a fingertip is present within the detection range of the sensor unit 2. The detection range is the range in which the sensor unit 2 can detect that a non-contact switch operation has been performed. Hereinafter, the maximum distance within the detection range will be referred to as the upper detection distance L. The non-emission level is the light-receiving level detected by the light-receiving element 212 when the light-emitting element 211 is not emitting light, and is also called the background light level. The emission level is the light-receiving level detected by the light-receiving element 212 when the light-emitting element 211 is made to emit light. The light-emitting element 211 emits illumination light of an intensity corresponding to the amplitude of the drive signal, according to the drive signal from the control unit 3, for a period of time corresponding to the pulse width of the drive signal.

[0016] The light-receiving element 212 is configured to have a directivity such that when a fingertip is positioned at the upper detection distance L from the top surface 23a of the housing, the entire effective surface of the light-receiving beam is blocked by the finger, that is, background light reaching the light-receiving element 212 is suppressed. The effective surface of the light-receiving beam refers, for example, to the range from the direction with the best light-receiving sensitivity to the point where the light-receiving sensitivity drops by 3 dB. The light-receiving element 212 receives reflected light based on the light emitted 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. Note that the level adjustment of the light-receiving signal may be either amplification or attenuation. Also, the light-receiving signal does not necessarily need to be level-adjusted and may be AD-converted directly.

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

[0018] Background light can range from approximately 500 Lx indoors on a sunny day, to approximately 10,000 Lx in the shade on a sunny day, and can reach as high as 100,000 Lx in direct sunlight on a sunny day. In other words, background light fluctuates greatly depending on the weather, time, and location, and especially when used while moving in a vehicle, the background light will experience repeated large fluctuations in a short period of time. However, as mentioned above, when a fingertip is within the detection range, the relative position of the fingertip and the element 21 prevents direct sunlight from directly entering the element 21. For example, even if the maximum value of direct sunlight entering from the front is 120,000 Lx, and the fingertip blocks up to 30° from the front, the direct sunlight will still enter at approximately 100,000 Lx. The optical touchless sensor 1 is required to operate normally even in environments where such background light enters.

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

[0020] Returning to Figure 1, the output function setting unit 4 instructs the control unit 3 on the format (hereinafter referred to as switch type) in which the detection result from the sensor unit 2 will be output. The output function setting unit 4 may be a physical switch, or it may be a terminal device that has a function to set the output function by operating on a screen or the like. Switch types 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 and lamps, etc. The external display unit 5 may be a display device provided on the device that is the controlled object 100, or a display device provided on the terminal device to which the optical touchless sensor 1 is connected, etc.

[0022] The proximity sensor 6 outputs an activation signal to the control unit 3 while detecting that an object, such as a person, has entered 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 centered around a microcomputer equipped with a CPU 35, ROM 36, RAM 37, etc. The various functions of the microcomputer are realized by the CPU 35 executing a program stored in a non-transitional physical recording medium. In this example, ROM 36 corresponds to the non-transitional physical recording medium that stores 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 hardware-wise by one or more ICs, etc. Also, the number of microcomputers constituting the control unit 3 may be one or more. ROM 36 may include a non-volatile memory such as an EPROM whose stored contents can be rewritten. The EEPROM may be configured so that the settings contents set by the output function setting unit 4 are written to it. In this case, when executing a process, the control unit 3 may refer to the settings contents written to the EEPROM and operate according to the settings contents.

[0024] The control unit 3 comprises, functionally speaking, a measurement unit 31, an operation output unit 32, and a diagnostic unit 33. The measurement unit 31 measures the non-light-emitting level and the light-emitting level using the element unit 21, and detects whether or not an operation was performed on the operation panel 24 of the sensor unit 2 from the measurement results.

[0025] The operation output unit 32 generates a switch output SW in a pattern corresponding to the switch type set in the output function setting unit 4 and outputs it to the controlled object 100. The operation output unit 32 may also have a function to display the operating status and setting status of the optical touchless sensor 1 on the unit display unit 22 or external display unit 5 based on the signals handled by the measurement unit 31 and the operation output unit 32.

[0026] The diagnostic unit 33 has the function of detecting abnormalities in the element unit 21. [1-2. Processing] [1-2-1. Measurement Process] The measurement process performed by the control unit 3 to realize the function of the measurement unit 31 will be explained using the flowchart in Figure 4.

[0027] The measurement process is repeatedly executed while the control unit 3 is running. However, if the optical touchless sensor 1 is equipped with a proximity sensor 6, the measurement process may be repeatedly executed only while an activation signal is input from the proximity sensor 6, that is, only while an object that has entered within a predetermined range from the sensor unit 2 is detected.

[0028] In S110, the measurement unit 31 outputs an instruction to turn off the light-emitting element 211 and resets the status ST, which represents the operation status of the control panel, to its initial value of 0. In S120, the measurement unit 31 determines whether or not it is time to measure. If it is time to measure, it proceeds to S130; otherwise, it waits by repeating the same step. The measurement timing may be a timing at a fixed period, or it may be the timing when a measurement instruction is input from an external source by some method.

[0029] In S130, the measurement unit 31 measures the non-emitting level. That is, the measurement unit 31 measures the light-receiving level of the light-receiving element 212 while keeping the light-emitting element 211 in a non-emitting state. In S140, the measurement unit 31 measures the light emission level. That is, the measurement unit 31 puts the light-emitting element 211 into a light-emitting state and measures the light-receiving level of the light-receiving element 212.

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

[0031] Specifically, the emission time Tp is set so that the heat loss in the light-emitting element 211 due to the irradiated light is below the allowable value of the light-emitting element 211, taking into account the emission interval of the light-emitting element 211 (i.e., the measurement period of the emission level) when the light-emitting element 211 is emitted at a pulse intensity that yields a reference reflection level. The emission time Tp is set to, for example, about 50 μs.

[0032] By measuring the emission level immediately following the non-emission level, the timing difference between the non-emission and emission levels becomes the same length as the measurement period Tw, as shown in the lower part of Figure 5.

[0033] Furthermore, the measurement period (i.e., the timing difference in the measurement) Tw is set to a time that is less than or equal to the time during which the position of the moving object in the external environment can be considered unchanged, assuming that the optical touchless sensor 1 is mounted on a moving object such as a vehicle. Note that since the movement of the moving object is faster than the movement of the 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 remain unchanged.

[0034] Here, if the distance traveled by the moving object during the measurement period Tw is, for example, less than or equal to half the width of a finger, preferably less than or equal to 1 mm, and more preferably less than or equal to 0.1 mm, then it is assumed that there is no change in the relative position. If the set speed of the vehicle is 100 km / h, then 100 km / h is converted to 27.8 μm / μs. In this case, if the measurement period Tw is 36 μs or less, the distance traveled by the moving object during that period will be less than or equal to 1 mm. From this, if Tw < 100 μs, it can be assumed 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-emitting level and the emitting level under conditions where 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-emitting level measured in S130 is within the acceptable range. If it is within the acceptable range, the process moves to S170; otherwise, the process moves to S160. The light received signal from the light receiving element 212 is amplified, then AD converted and input to the control unit 3. Therefore, the measurement unit 31 determines that the amplified signal is outside the acceptable range if it is saturated or below the lower limit level.

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

[0037] In S180, the measurement unit 31 determines whether the detection level LV calculated in S170 is greater than the provisional selection threshold THa. If LV > THa, the process proceeds to S190; if LV ≤ THa, the process proceeds to S200. The provisional selection threshold THa is set to a magnitude that allows for the 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 photodetector 212.

[0038] In S190, the measurement unit 31 displays a provisional selection using the unit display unit 22 and proceeds to S200. The provisional selection display informs the operator that although the detection level LV is not yet at the level required to determine that an operation has been performed on the operation panel 24, if the detection level LV rises by bringing a finger or other object a little closer, an operation will be determined to have occurred.

[0039] In S200, the measurement unit 31 determines whether the detected level LV is greater than the selection threshold THb. If LV > THb, the process proceeds to S210; 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, indicating that an operation has been performed on the operation panel 24. In S220, the measurement unit 31 switches the provisional selection display on the unit display unit 22 to the selected display and returns the process to S120. In the selected display, the display manner on the unit display unit 22 may be different from that of the provisional selection display, such as by using a different display color.

[0041] In S230, the measurement unit 31 sets the status ST to 0, indicating that no operation has been performed on the control panel, and returns the process to S120. Here, the operation of each part according to the measurement process will be explained using the timing diagram in Figure 5.

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

[0043] In other words, when measuring the level in the non-emitting state, the value of the background light is sampled, and when measuring the level in the emitting state, the value of the sum of the background light and reflected light is sampled. The non-emitting level and the emitting level are sampled at timings shifted by the measurement period Tw. Furthermore, the measurement period Tw is set so that the background light conditions (i.e., the position of the sensor unit 2 relative to the external environment) and the reflected light conditions (the position of the fingertip operating the sensor unit 2) are considered 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 reflected light only, with the influence of background light removed. When this detection level LV is equal to or greater than the threshold TH, a determination result is obtained that there has been an operation on the operation panel 24 of the sensor unit 2, and the status ST is set according to that determination result.

[0045] [1-2-2. Output Processing] The output processing performed by the control unit 3 to realize the function of the operation output unit 32 will be explained using the flowchart in Figure 6.

[0046] Output processing is performed each time the status ST is set in S190 or S200 of the measurement process. In S310, the operation output unit 32 determines whether the switch type specified by the output function setting unit 4 is momentary or not. If the operation output unit 32 determines that the switch type is momentary, it proceeds to S320; if it determines that it is not momentary (i.e., alternate), it proceeds to S350.

[0047] In S320, the operation output unit 32 determines whether the value of status ST is 1 or not. If ST=1, the process moves to S330; if ST=0, the process moves to S340. In S330, the operation output unit 32 sets the switch output SW to a value indicating "on" and terminates the process.

[0048] In S340, the operation output unit 32 sets the switch output SW to a value indicating "off" and terminates the process. In S350, the operation output unit 32 determines whether the value of status ST has changed from 0 to 1. If it has changed from 0 to 1, the process proceeds to S360. Otherwise, i.e., if the value of status ST has not changed or has changed from 1 to 0, the process terminates.

[0049] In S360, the operation output unit 32 reverses the on / off state of the switch output SW to terminate the process. As shown in Figure 7, in the momentary case, the status ST is output directly as the switch output SW. In the alternate case, the on / off state of the switch output SW is reversed each time the status ST changes from 0 to 1.

[0050] Here, only momentary and alternate switches have been described as switch types implemented by the operation output unit 32. However, the system is not limited to these, and can be configured to implement any switch type, such as "N / O," "N / C," "multi-pole," or "multi-throw." "N / O" and "N / C" refer to the difference in how the output is displayed when the switch is on or off in the case of a momentary switch. "N / O" represents a type where the switch output SW is off when no switch operation is performed (i.e., ST=0). "N / C" represents a type where the switch output SW is on when no switch operation is performed (ST=0). "Multi-pole" represents a switch that controls multiple circuits simultaneously, and "multi-throw" represents a switch that controls multiple connection paths.

[0051] [1-2-3. Diagnostic Process] The diagnostic process for diagnosing the state of the element unit 21 will now be described. In the diagnostic process, the non-luminescent level and the luminescent level are measured with no operating object such as a fingertip within the detection range.

[0052] As shown in Figure 8, a portion of the light emitted from the light-emitting element 211 is repeatedly reflected at the interface of the operation panel 24, propagates within the operation panel 24, and is received by the light-receiving element 212. In other words, the light-receiving level obtained in the emission measurement is slightly higher than the light-receiving level obtained in the non-emission measurement, even when no reflective material is present. In the diagnostic process, the state of the element unit 21 is diagnosed by using the non-emission level (hereinafter referred to as the non-emission diagnostic level) and the emission level (hereinafter referred to as the emission diagnostic level), which are stored in advance as diagnostic data in the ROM 36 or the like.

[0053] The diagnostic process performed by the control unit 3 to realize the function of the diagnostic unit 33 will be explained using the flowchart in Figure 9. The diagnostic process may be executed as one of the initialization processes immediately after the control unit 3 starts up, or it may be executed in accordance with an external instruction.

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

[0055] In S540, the diagnostic unit 33 compares the non-luminescence level and the luminescence level with the non-luminescence diagnostic level and luminescence diagnostic level shown in the diagnostic data to determine whether there is an abnormality and the cause of the abnormality.

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

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

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

[0059] As shown in Pattern 4, if the ratio of the non-emitting level to the emitting level is about the same as the ratio of the non-emitting reference level to the emitting reference level, but the overall level is lower, it is determined that this is an abnormality due to deterioration of the photodetector 212.

[0060] Returning to Figure 9, in S550, the diagnostic unit 33 notifies the predetermined destination of the diagnostic results and terminates the process. The diagnostic results may also be displayed on the external display unit 5. [1-3. Effects] The first embodiment described in detail above provides the following effects.

[0061] (1a) The optical touchless sensor 1 measures the non-light level and the light-emitting level at short intervals that can be considered as measurements under the same external environment, and determines from the measurement results whether there is an operating object such as a fingertip within the detection range, and consequently whether there is an operation on the operation panel 24. Therefore, with the optical touchless sensor 1, even in environments where the intensity of background light changes rapidly and significantly, measurements can be performed with the influence of background light suppressed, and touchless switch operations can be detected with high accuracy.

[0062] (1b) In the optical touchless sensor 1, the directivity of the light-receiving element 212 is set so that when the fingertip, which is the operating object, is within the detection range, background light is prevented from entering the element part 21 from the front. Furthermore, the level of the illumination light emitted by the light-emitting element 211 is set so that the illumination level (i.e., the illumination reference level) in this case is greater than the non-illumination level (i.e., the non-illumination reference level). Therefore, the optical touchless sensor 1 can detect touchless switch operation even in environments 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 constructed using a relatively inexpensive and low-power light-emitting element 211. In other words, by shortening the light emission time Tp of the light-emitting element 211 to about 50 μs, the light emission is stopped before the temperature of the light-emitting element 211 rises, so the light-emitting element 211 can emit light at 10 to 100 times the normally allowable brightness. For this reason, the optical touchless sensor 1 can operate normally even in environments where the background light changes rapidly in a wide range of 100 to 100,000 Lx, such as a vehicle driving in direct sunlight.

[0064] As described in Patent Document 1, the reflected light from the object being detected accounts for only a few percent of the light emitted from the light-emitting element. Therefore, in situations 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 being detected is buried by the background signal based on the background light, making it difficult to detect the object being detected. In contrast, the optical touchless sensor 1 employs a flash-like emission, enabling emission at 10 to 100 times the normally permissible brightness. In other words, it is possible to realize a technology that obtains a detection signal that is not buried by the background signal without applying complex processing to the received signal as described in Patent Document 1, and consequently, a technology that improves the detection accuracy of objects such as fingers.

[0065] (1d) In the optical touchless sensor 1, the size of the opening that houses the element part 21, which is formed on the upper surface 23a of the housing of the sensor unit 2, is formed to be narrower than the width of the fingertip, which is the operating object. Therefore, even if a situation arises where touchless switch operation does not work properly due to the influence of background light, the incidence of background light on the element part 21 can be prevented by touching the fingertip to the operation panel 24. Furthermore, the infrared light emitted has the property of penetrating into the inside of the finger, diffusing and propagating, and is received by the light receiving element 212 via the finger, so the switch operation of the optical touchless sensor 1 can be operated while the incidence of background light is blocked. In other words, it is possible to suppress the optical touchless sensor 1 from becoming inoperable due to the influence of background light. To put it another way, there is no need to prepare a separate touch switch in case of such an unforeseen 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 provisional selection threshold THa, a provisional selection display is made using the unit display unit 22. When the detection level LV exceeds the selection threshold THb, it is determined that an operation has been made on the operation panel 24, and the provisional selection display is switched to a selected display. Therefore, the operator can prevent situations in which an operation is mistakenly determined to have been made when there is no intention to operate due to the provisional selection display, or where an operation is not determined to have been made when there is an intention to operate due to insufficient proximity of the object to be detected, such as a finger.

[0067] (1f) The optical touchless sensor 1 diagnoses the state of the element unit 21 by comparing the non-emitting level and emitting level, which are measured when there is no object to operate within the detection range, with the non-emitting diagnostic level and emitting diagnostic level. Since the diagnosis utilizes light propagated through the operation panel 24 and received by the photodetector 212, there is no need to install special equipment for diagnosis, and a simple diagnosis can be achieved.

[0068] (1g) In the optical touchless sensor 1, the switch type can be selected via the output function setting unit 4, and an appropriate switch output SW can be provided according to the controlled object 100. Alternatively, the switch type may be written to a non-volatile memory whose contents can be rewritten using the output function setting unit 4. In this case, the switch type can be set or changed at any time, such as during the manufacture or installation of the optical touchless sensor 1, and the set or changed contents can be retained, thereby improving the usability of the optical touchless sensor 1.

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

[0070] [2. Second Embodiment] [2-1. Differences from the First Embodiment] The second embodiment has the same basic configuration as the first embodiment, so the differences will be explained below. Note that the same reference numerals as in the first embodiment indicate the same components, and refer to the preceding description.

[0071] In the first embodiment described above, only one sensor unit 2 is provided. In contrast, the second embodiment differs from the first embodiment in that it is provided with multiple sensor units 2, and it performs processing to determine which of the multiple sensor units 2 has been operated.

[0072] [2-2. Structure] As shown in Figure 11, the optical touchless sensor 1a of the second embodiment includes a group of sensor units 7, which includes multiple 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 target 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 target determination unit 34 performs operation target determination processing based on the output from the measurement unit 31a. The operation target determination unit 34 outputs the measurement results of the sensor units 2 that have been determined to be the target of operation by the operation target determination processing to the operation output unit 32.

[0074] As shown in Figure 12, the multiple sensor units 2 belonging to the sensor unit group 7 are arranged in close proximity and are used, for example, as switches to specify a floor when operating an elevator. As shown in Figure 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 a person is in close proximity to the sensor unit group 7, there is a possibility that multiple sensor units 2 may be mistakenly identified as being operated due to reactions to different 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 temporarily selected switch) is set. If the temporarily selected switch is not set, the process proceeds to S650; if the temporarily selected 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 associated with the maximum level LV1 to the temporarily selected switch, and performs a temporary selection display indicating that it is temporarily selected using the unit display unit 22 of the temporarily selected 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 equal to or greater than a second detection threshold value TH2 that is set to a value greater than the first detection threshold value 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 as the selection switch. Further, the operation target determination unit 34 uses the unit display unit 22 of the selection switch to switch from a display indicating a temporary selection to a 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, such as different display colors.

[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 levels 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 give the operator a sense of security.

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

[0092] (3a) In the above embodiment, an example of the emission intensity (i.e., pulse intensity) and emission time (i.e., pulse width) of the irradiated light was shown, but the emission intensity and emission time can be appropriately optimized depending on the brightness of the measurement location, the type of controlled object 100, etc.

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

[0094] (3c) In the above embodiment, near-infrared light with a wavelength of approximately 800 nm to 1000 nm is used as the irradiating light. The irradiating light is not limited to near-infrared light, and various wavelengths of light can be used as long as they do not have any effect on the human body.

[0095] (3d) In the above embodiment, the presence or absence of operation is determined by a single threshold TH based on the detection level LV. For example, the threshold may have hysteresis. As shown in Figure 16, if the detection level LV is expressed in 10 steps, the threshold for switching from off to on is set to, for example, level 6.5, and the threshold for switching from on to off is set to, for example, level 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 comprises one light-emitting element 211 and one light-receiving element 212. However, as shown in Figure 17, it may also comprise one light-emitting element 211 positioned in the center and a plurality of light-receiving elements 212 positioned around the light-emitting element 211. For example, the light-receiving elements 212 may be positioned at four locations above, below, to the left, and to the right of the light-emitting element 211, or they may be positioned at a total of eight locations, including 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. Alternatively, instead of providing multiple light-receiving elements 212, multiple combinations of light-emitting elements 211 and light-receiving elements 212 may be arranged at multiple locations. In this case, the central set may be omitted.

[0097] (3f) Multiple functions of one component in the above embodiment may be realized by multiple components, or one function of one component may be realized by multiple components. Also, multiple functions of multiple components may be realized by one component, or one function realized by multiple components may be realized by one component. Furthermore, some of the configuration of the above embodiment may be omitted. Also, at least some of the configuration of the above embodiment may be added to or replaced with the configuration of other above embodiments.

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

[0099] [4. The technical concepts disclosed herein] [Item 1] It is an optical touchless sensor, A sensor unit comprising a light-emitting element that emits light in a predetermined irradiation direction, and a light-receiving element that receives light arriving from the said irradiation direction. A control unit is configured to measure the non-emitting level, which is the light-receiving level at the photodetector when the light-emitting element is not emitting light, and the emitting level, which is the light-receiving level at the photodetector when the light-emitting element is emitting light, and to determine the presence or absence of an object to be manipulated within the detection range according to a detection level that represents the difference between the non-emitting level and the emitting level. Equipped with, The timing difference between the measurement of the non-emitting level and the emitting level is set to a time interval such that the position of the mobile body in the external environment can be considered the same, even if the mobile body equipped with the optical touchless sensor is moving at a set speed. Optical touchless sensor.

[0100] [Item 2] The optical touchless sensor described in item 1, The directivity of the light-receiving element is set such that the light-receiving beam is blocked by the operating object within the detection range. The light emission intensity of the light-emitting element is set such that the light emission level and the non-light emission level, measured when the manipulated object is present within the detection range, are greater when the light emission level is greater than when the non-light emission level is greater. Optical touchless sensor.

[0101] [Item 3] A light touchless sensor as described in item 1 or item 2, The light-emitting element is configured such that the pulse width of the emitted light, the emission interval, and the emission intensity are set so that the heat loss due to light emission is below the allowable value of the light-emitting element. Optical touchless sensor.

[0102] [Item 4] A light touchless sensor as described in any one of items 1 to 3, The sensor unit comprises a housing that houses the light-emitting element and the light-receiving element, and has an opening for allowing light emitted and received by the light-emitting element and the light-receiving element to pass through. The opening is formed to be large enough to be completely covered by the operating object. Optical touchless sensor.

[0103] [Item 5] The optical touchless sensor described in item 4, The sensor unit further comprises 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. The system further comprises a diagnostic unit configured to diagnose the state of the sensor unit based on the non-emitting level and the emitting level measured when the operating object is not present within the detection range. Optical touchless sensor.

[0104] [Item 6] An optical touchless sensor as described in any one of items 1 to 5, The manipulated object is the fingertip of the hand. Optical touchless sensor.

[0105] [Item 7] An optical touchless sensor as described in any one of items 1 through 6, A group of sensor units comprising multiple sensor units that are operated individually, The control unit determines that an operation has been performed on the target sensor unit when the following conditions are met: the sensor unit with the highest detection level among the sensor units belonging to the sensor unit group is designated as the target sensor unit, and the sensor unit with the second highest detection level is designated as the comparison sensor unit. The control unit determines that an operation has been performed on the target sensor unit when the following conditions are met: the detection level of the target sensor unit is equal to or greater than the detection threshold, and the difference between the detection level of the target sensor unit and the detection level of the comparison sensor unit is equal to or greater than the effectiveness determination threshold. Optical touchless sensor.

[0106] [Item 8] The optical touchless sensor described in item 7, Each of the aforementioned sensor units is further provided with a unit display unit configured to display in multiple display modes, The control unit is configured to display a provisional selection on the unit display unit of the target sensor unit in a first manner indicating that it is the target sensor unit, and, if the selection condition is met, to display a selection on the unit display unit of the target sensor unit in a second manner different from the first manner. 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 of housing, 24...Operation panel, 31,31a...Measurement unit, 32...Operation output unit, 33...Diagnostic unit, 34...Operation target determination unit, 35...CPU, 36...ROM, 37...RAM, 100...Control target, 211...Light-emitting element, 212...Light-receiving element.

Claims

1. It is an optical touchless sensor, A sensor unit comprising a light-emitting element that emits light in a predetermined irradiation direction, and a light-receiving element that receives light arriving from the said irradiation direction. A control unit is configured to measure the non-emitting level, which is the light-receiving level at the photodetector when the light-emitting element is not emitting light, and the emitting level, which is the light-receiving level at the photodetector when the light-emitting element is emitting light, and to determine the presence or absence of an object to be manipulated within the detection range according to a detection level that represents the difference between the non-emitting level and the emitting level. Equipped with, The timing difference between the measurement of the non-emitting level and the emitting level is set to a time interval such that the position of the mobile body in the external environment can be considered the same, even if the mobile body equipped with the optical touchless sensor is moving at a set speed. Optical touchless sensor.

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

3. The optical touchless sensor according to claim 1, The light-emitting element is configured such that the pulse width of the emitted light, the emission interval, and the emission intensity are set so that the heat loss due to light emission is below the allowable value of the light-emitting element. Optical touchless sensor.

4. The optical touchless sensor according to claim 1, The sensor unit comprises a housing that houses the light-emitting element and the light-receiving element, and has an opening for allowing light emitted and received by the light-emitting element and the light-receiving element to pass through. The opening is formed to be large enough to be completely covered by the operating object. Optical touchless sensor.

5. The optical touchless sensor according to claim 4, The sensor unit further comprises 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. The system further comprises a diagnostic unit configured to diagnose the state of the sensor unit based on the non-emitting level and the emitting level measured when the operating object is not present within the detection range. Optical touchless sensor.

6. The optical touchless sensor according to claim 1, The manipulated object is the fingertip of the hand. Optical touchless sensor.

7. The optical touchless sensor according to claim 1, A group of sensor units comprising multiple sensor units that are operated individually, The control unit determines that an operation has been performed on the target sensor unit when the following conditions are met: the sensor unit with the highest detection level among the sensor units belonging to the sensor unit group is designated as the target sensor unit, and the sensor unit with the second highest detection level is designated as the comparison sensor unit. The control unit determines that an operation has been performed on the target sensor unit when the following conditions are met: the detection level of the target sensor unit is equal to or greater than the detection threshold, and the difference between the detection level of the target sensor unit and the detection level of the comparison sensor unit is equal to or greater than the effectiveness determination threshold. Optical touchless sensor.

8. The optical touchless sensor according to claim 7, Each of the aforementioned sensor units is further provided with a unit display unit configured to display in multiple display modes, The control unit is configured to display a provisional selection on the unit display unit of the target sensor unit in a first manner indicating that it is the target sensor unit, and, if the selection condition is met, to display a selection on the unit display unit of the target sensor unit in a second manner different from the first manner. Optical touchless sensor.

Images