JP2004309173A - Distance measuring instrument for object to be measured, distance measuring sensor, and automatic faucet device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent malfunction due to ranging error caused by reflected light from a specular reflective object with respect to a distance measuring instrument for measuring a distance to an object to be measured by emitting light toward the object and receiving reflected light from the object. <P>SOLUTION: This distance measuring instrument 10 is equipped with a light emitting part 11 for emitting light toward the object to be measured, a plurality of light receiving parts 13a to 13b for receiving reflected light from the object to be measured to perform outputting to show the distance to the object to be measured correspondently to the incident angle of the reflected light, and a detection means 2 for detecting the object to be measured when output values of at least two light receiving parts among these light receiving parts show a prescribed distance or less. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to an automatic faucet device that automatically detects and discharges water by stopping a person or tableware.
[0002]
[Prior art]
2. Description of the Related Art In recent years, a wash basin or a kitchen has been provided with an automatic faucet device that detects a person, tableware, and the like to automatically discharge and stop water (for example, Patent Document 1).
FIG. 12 is a diagram showing an automatic faucet device disclosed in Patent Document 1. The automatic faucet device 152 includes a valve 161, a controller 151, and the like provided in the flush 163 of the kitchen sink 167.
[0003]
A water supply channel 171 through which hot and cold water from a hot and cold water supply device 169 flows is connected to the water washing 163, and a water outlet 165 is provided at a distal end, and a distance from an object such as a human body or an object is provided at a distal end or a base. A distance measuring sensor (hereinafter, referred to as a distance measuring sensor) 150 is provided as measuring means for measuring the distance.
[0004]
FIG. 13A shows a configuration diagram of the distance measuring sensor 150. As shown in the drawing, the distance measuring sensor 150 is a known sensor including an infrared light emitting element 31, a light emitting side lens 21, a light receiving side lens 23, and a position detecting element (PSD sensor) 33. The distance measurement sensor 150 has a measurement area in a substantially horizontal direction, and light emitted from the infrared light emitting element 31 is reflected by the object to be measured 5 through the light emitting side lens 21, and the light is The measurement distance L from the object 5 is captured according to the position X condensed on the position detection element 33 through the light receiving side lens 23.
[0005]
The distance between the light emitting side lens 21 and the light receiving side lens 23 is set to P, and the distance between the light receiving side lens 23 and the position detecting element 33 is set to d. Therefore, geometrically, the measurement distance L is obtained as L = P × d / X.
FIG. 13B is a diagram illustrating the position detecting element 23 used in the distance measuring sensor 150. The position detection element 23 outputs currents i1 and i2 as signals generated according to the displacement y of the spot light condensed by the light receiving side lens from the sensor center position to a controller 151 described later.
[0006]
FIG. 13C is a schematic configuration diagram of the controller 151. The controller 151 activates the distance measuring sensor 150 and controls opening and closing of the valve 161 based on the signal currents i1 and i2.
[0007]
Inside the controller 151, amplifiers 511 and 512, A / D converters (ADCs) 531 and 532, and an operation unit 45 are provided. As described above, the currents i1 and i2 input from the distance measurement sensor 150 are output. Then, distance data corresponding to the measured distance L is calculated.
That is, the arithmetic unit 45 converts the currents i1 and i2 into voltages by the amplifiers 511 and 512 to obtain v1 and v2, respectively, and converts these to digital signals by the A / D converters 531 and 532, respectively. The displacement y of the spot light from the center of 33 is calculated by y = (v2−v1) / (v1 + v2).
Then, based on the calculated displacement y and the displacement between the center of the light receiving side lens 23 and the center of the distance measuring sensor, the light condensing position X is obtained, and the measured distance L = P × d / X is calculated.
The controller 151 determines whether or not the measured distance is within a predetermined working distance, and controls the opening and closing of the valve 161 when the measured distance is within the predetermined working distance.
[0008]
[Patent Document 1]
JP-A-2002-194873 (paragraphs [0019] to [0027])
[0009]
[Problems to be solved by the invention]
As shown in FIG. 14, when the target object 5 (such as a human hand) is not in the detection range of the distance measuring sensor 150, the light emitted from the infrared light emitting element 31 is reflected on the bottom surface or the inner wall of the sink 167. The position is detected by the position detecting element 33. However, since the inner wall of the sink 167 is provided at a position outside the predetermined detection range, the controller 151 does not control the opening and closing of the valve 161 even when the position detection element 33 receives the reflected light from the inner wall of the sink 167. .
[0010]
However, in the conventional automatic faucet device 152, there is a case where the measurement distance to the wall surface of the sink 167 is incorrectly calculated and the valve opening / closing control is performed. The reason is as follows.
[0011]
FIG. 15 is a diagram illustrating the difference in the light collection position due to the reflected light between the diffuse reflector such as a human hand and the specular reflector such as the wall surface of the sink 167.
As shown in FIG. 15A, when the light emitted from the infrared light emitting element 31 is reflected by the object 5 which is a diffuse reflector, the reflected light is received by the entire light receiving side lens 23. Therefore, the reflected light is condensed on the position detecting element 33 at a position corresponding to the angle of incidence on the light receiving side lens 23, and the distance to the object 5 can be accurately measured by the condensing position.
[0012]
However, when the light emitted from the infrared light emitting element 31 is reflected on the specular reflector 167, the reflected light becomes spot-like reflected light. Therefore, as shown in FIGS. 15B and 15C, even when the distance between the light receiving side lens 23 and the specular reflector 167 is kept constant, the light emitting optical axis from the infrared light emitting element 31 and the specular reflector 167 are As a result, the position of light condensed on the position detection element 33 changes.
Due to the change in the light condensing position, the signal currents i1 and i2 change, causing a change in the measurement distance calculated by the calculation unit 45, and erroneously calculating the distance to the sink 167, which is a specular reflection object. FIG. 16 shows the relationship between the change in the angle formed between the light emitting optical axis and the specular reflector 167 and the measurement distance. The graph is a result of the measured distance L obtained when the distance between the distance measuring sensor 150 and the specular reflector 167 is kept constant and the angle between the light emitting optical axis and the specular reflector 167 is changed.
[0013]
Therefore, in the conventional automatic faucet device 152, it is necessary to pay attention to the installation position of the distance measuring sensor 150 and the like so that the distance from the sink 167 or the like is not erroneously measured and malfunctioning. And the inconvenience of restricting the design of the kitchen.
[0014]
An object of the present invention is a distance measuring sensor for emitting light toward an object, receiving reflected light from the object and measuring the distance to the object to be measured, a distance measuring device and an automatic faucet device. An object of the present invention is to prevent a malfunction due to a distance measurement error caused by light reflected from the above-mentioned specular reflection object.
[0015]
[Means for Solving the Problems]
In order to achieve the above object, a distance measuring device according to the present invention is provided with a plurality of light receiving elements for receiving reflected light from an object to be measured, and an output value of at least two of the light receiving elements is a predetermined distance. When the following is shown, the object to be measured is detected.
[0016]
FIG. 1 is a basic configuration diagram of a distance measuring device according to a first embodiment of the present invention.
The distance measuring device 10 includes a control unit 2 serving as a detecting unit and a distance measuring sensor 3 (hereinafter, referred to as a distance measuring sensor 3). The distance measuring sensor 3 emits light toward a target object 5 which is an object to be measured. The control unit 2 includes a light receiving unit 13a and a plurality of light receiving units 13a and 13b that receive reflected light from the object 5 and output the distance to the object according to the incident angle. A distance calculation unit 43 for calculating a distance to the target object 5 based on the output values from the first and the third objects, and a detection possibility determination unit 41 for permitting detection of the target object 5.
[0017]
The light emitting section 11 includes an infrared light emitting element 31 and a light emitting side lens 21. The light receiving sections 13a and 13b include light receiving side lenses 23a and 23b and position detecting elements (PSD sensors) 33a and 33b, respectively. The light receiving units 13a and 13b are provided at different positions.
[0018]
When the output values of the two light receiving units 13a and 13b both indicate a predetermined distance or less, the detection possibility determination unit 41 outputs a permission signal for permitting detection of the target object 5 to the distance calculation unit 43. The distance calculation unit 43 that has received the permission signal calculates the distance to the object 5 based on the output values from the light receiving units 13a and 13b.
[0019]
The operation of the distance measuring device 10 will be described with reference to FIG.
As shown in FIG. 2A, when the light emitted from the light emitting unit 11 is reflected on the object 5 which is a diffuse reflector, the light receiving units 13 a and 13 b provided at different positions are different from each other. Irrespective of the angle between the optical axis and the object 5, reflected light is received by the entire light-receiving-side lenses 23 a and 23 b, and a measurement result signal is output according to the measurement distance L.
[0020]
On the other hand, when the light emitted from the light emitting unit 11 is reflected on the specular reflector 167, the light received at different positions depending on the angle between the optical axis of the emitted light and the object 5 as shown in FIG. The light receiving state is different between the portions 13a and 13b.
For example, in the case shown in FIG. 2B, the light receiving unit 13a that receives the reflected light from the specular reflector 167 measures the measurement distance L to be a relatively short distance, but hardly receives the reflected light. The light receiving unit 13b measures that the measurement distance L is a very long distance. The difference between the two light receiving states provided at different positions increases as the distance between the specular reflector 167 and the distance measurement sensor 3 increases.
Therefore, when the distance measurement sensor 3 receives the reflected light from the specular reflection object such as the inner surface of the sink 167 outside the detection range of the target object detected by the distance measurement device 10, the measurement result signal of one of the light receiving units indicates the measurement distance. While L is indicated as a short distance, the measurement result signal of the other light receiving unit indicates the measured distance L as a long distance.
Therefore, the detection possibility determination unit 41 determines whether or not to detect the target object 5 only when the detection signals of the light receiving units 13a and 13b both indicate a predetermined distance or less. 10 can prevent erroneous detection due to light reflected from the specular reflector 167.
[0021]
However, according to the basic configuration, it is necessary to increase the number of light receiving elements as compared with a conventional distance measuring device. In order for a detecting means constituted by a microcomputer or the like to read a signal from the light receiving element, it is necessary to provide a conversion circuit such as an amplifier element and an A / D converter. The number of conversion circuits also increases, resulting in an increase in circuit size and current consumption.
[0022]
Therefore, the distance measuring device according to the second aspect of the present invention includes switching means for selecting outputs from the plurality of light receiving units and inputting the outputs to the detecting means. This makes it possible to reduce the size, cost, and power consumption of the circuit.
[0023]
Further, the distance measuring sensor according to the third aspect of the present invention is a light emitting unit that emits light toward the measured object, receives light reflected from the measured object, and receives the reflected light from the measured object according to the incident angle. A plurality of light receiving units for outputting an indication of the distance are provided, and at least one light receiving unit is provided at a position opposite to any other light receiving unit with respect to the light emitting unit.
[0024]
Further, an automatic faucet device according to a fourth aspect of the present invention includes the distance measuring device according to the first aspect.
[0025]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 3 is a block diagram of the distance measuring device according to the first embodiment of the present invention.
The distance measuring device 10 includes a control unit 2 and a distance measuring sensor 3 as in the above-described basic configuration. The distance measuring sensor 3 includes a light emitting unit 11 and light receiving units 13a and 13b. It includes a unit 43 and a detection possibility determination unit 41.
[0026]
The light emitting section 11 is composed of an infrared light emitting element 31 and a light emitting side lens 21, and the light receiving sections 13a and 13b are well-known elements including light receiving side lenses 23a and 23b and position detecting elements (PSD sensors) 33a and 33b. Here, for the sake of simplicity, it is assumed that the light receiving units 13a and 13b are arranged at equal distances in opposite directions with respect to the light emitting unit 11. The current output from the terminal close to the light emitting optical axis of the position detecting element 33a is i1, the current output from the far terminal is i2, and the current output from the terminal close to the light emitting optical axis of the position detecting element 33b is i3, far. The current output from the terminal is i4. As a result, the output ratios i2 / i1 and i4 / i3 increase as the object 5 is closer.
[0027]
The control unit 2 includes amplifiers 511 to 514, A / D converters (ADCs) 531 to 534, a detection possibility determination unit 41, and a distance calculation unit 43. The amplifiers 511 to 514 and the A / D converter (ADC) 531 to 534 convert the currents i1 to i4 into voltage signals v1 to v4 by voltage / analog-to-digital conversion, respectively, and output them to the detection possibility determination unit 41 and the distance calculation unit 43.
The distance calculation unit 43 uses the voltage signals v1 to v4 input from the A / D converters (ADC) 531 to 534 to calculate the displacements y1 and y2 of the condensing positions of the position detection elements 33a and 33b from the centers of the elements. To y1 = (v2−v1) / (v1 + v2)
y2 = (v4-v3) / (v3 + v4)
It is calculated by:
Here, when the distance between the light emitting side lens 21 and the light receiving side lens 23 is P, the distance between the light receiving side lens 23 and the position detecting element 33 is d, and the light condensing position is X, the measurement distance L is L as described above. = P × d / X. The light condensing position X can be determined by X = z + y, where z is a displacement between the center of the light receiving side lens and the center position of the position detecting element 33 in the direction orthogonal to the light emitting optical axis. Therefore, the distance calculation unit 43 calculates the measurement distances L1 and L2 for the displacements y1 and y2 calculated for each position detection element 33,
L1 = P × d / (z + y1)
L2 = P × d / (z + y2)
Can be calculated by
[0028]
As described above, when the light from the light emitting unit 11 is reflected by the diffuse reflector, the voltage signals v1 to v4 from the light receiving units 13a and 13b are signals indicating the same measurement distances L1 and L2, respectively. However, when the light is reflected by the specular reflector, the light condensing positions on the position detecting elements 33a and 33b change depending on the angle between the light emitting optical axis and the specular reflector, and the voltage signals v1 to v4 change. FIG. 4 shows a graph of voltage signals v1 to v4 when a mirror-reflected object located at a certain position outside the detection range of the distance measuring sensor 3 is measured at a different angle from the light emission optical axis.
[0029]
Since the reflected light from the specular reflection object is a spot light, as shown in the drawing, the range where the output from the position detection element 33a satisfies v1 ≦ v2 and the range where the output from the position detection element 33b satisfies v3 ≦ v4 ( That is, the measurement distance L ≦ P × d / z is not overlapped with the measurement range.
[0030]
Therefore, the detection possibility determination unit 41 compares the voltage signals v1 to v4 input from the A / D converters (ADC) 531 to 534, and only when v1 ≦ v2 and v3 ≦ v4, that is, Only when the output from the position detection element 33a, which is the output value from the light receiving units 13a and 33b, indicates the predetermined measurement distance L = P × d / z or less, the distance calculation unit 43. Outputs a permission signal indicating detection permission. In this way, the detection possibility determination unit 41 determines whether detection is possible, thereby preventing erroneous detection regardless of the angle of the specular reflection object at a certain position outside the detection range with the light emission optical axis. Becomes possible.
When receiving the permission signal from the detection possibility determination unit 41, the distance calculation unit 43 determines the distance to the object 5 from one of the measured distances L1 and L2 or an average thereof, and determines a predetermined distance. The object 5 is detected when it is within the detection range of.
[0031]
FIG. 5 shows an operation flowchart of the distance measuring device 10. The distance measuring device 10 causes the light emitting element 13 to emit light (S61), reads voltage signals v1 to v4 output from the position detecting elements 33a and 33b that have received the reflected light from the object 5 (S63), and then reads the light emitting element. The light emission of the object 13 is stopped (S65), and the distance from the object 5 is measured and / or the object 5 is detected only when v1 ≦ v2 and v3 ≦ v4 (S67, S69). , S71), otherwise the object 5 is not detected (S73).
[0032]
Instead of comparing the voltages v1 to v4, the detection possible / impossible judging unit 41 calculates the displacement y1 or y2 of the condensing position in the position detecting element, or the measurement distance L1, from the voltages v1 to v4 output from the light receiving units 13a and 13b. L2 may be calculated respectively, and based on this, it may be determined whether the object 5 can be detected. FIG. 6 shows graphs of y1 and y2 when the distance between a specular reflection object located at a certain position outside the detection range of the distance measurement sensor 3 and the light emission optical axis is changed.
[0033]
As shown in the figure, it can be seen that a threshold value yth can be set such that the angle ranges where y1 and y2 are each equal to or larger than a predetermined threshold value do not overlap each other. Therefore, the detection possibility determination section 41 may output a permission signal indicating detection permission to the distance calculation section 43 only when both the calculated y1 and y2 are equal to or larger than the predetermined threshold value yth. By thus determining whether or not detection is possible, it is possible to prevent erroneous detection of a specular reflection object at a fixed position outside the detection range.
Further, as described above, the measurement distances L1 = P × d / (z + y1) and L2 = P × d / (z + y2) are inversely proportional to the increments of y1 and y2, so that both L1 and L2 are equal to or less than the predetermined distance Lth. Even if the permission signal is output only when the mirror reflection object is detected, it is possible to prevent erroneous detection of a specular reflection object located at a certain position outside the detection range.
FIG. 7 shows a flowchart in which S67 and S69, which are the detection possibility determination steps in the flowchart of FIG. 5, are changed to determination steps S75 and S77 based on the displacement y1 or y2 of the focusing position.
[0034]
Various arrangements can be adopted for the light emitting unit 11 and the light receiving units 13a and 13b of the distance measuring sensor 3. FIG. 8 is a diagram illustrating an example of an arrangement of the light emitting unit 11 and the light receiving units 13a and 13b of the distance measuring sensor 3. In order to effectively detect the difference in light reception due to specular reflection light, as shown in FIG. 8A, the light receiving units 13a and 13b are placed on opposite sides of the light emitting unit 11, that is, the light receiving unit 13a and the light emitting unit 11 It is preferable that the line connecting the light emitting unit 11 and the light receiving unit 13b be provided at 180 °, but as long as a difference in light reception by specular reflected light can be detected, as shown in FIG. You may provide so that it may become narrower.
Further, the interval between the light receiving unit 13b and the light emitting unit 11 does not need to be provided at the same interval (a) as that between the light emitting unit 11 and the light receiving unit 13a, and as shown in FIG. When it is not provided at the same interval (a) between the unit 11 and the light receiving unit 13a, it may be provided at an interval (b) different from a.
[0035]
FIG. 9 shows a block diagram of the detecting means 2 of the distance measuring device according to the second embodiment of the present invention.
The detecting means 2 of the distance measuring device according to the second embodiment is provided with a multiplexer 91 which is a switching means for selecting the outputs of the plurality of light receiving sections 13a and 13b and inputting the outputs to the detecting means.
FIG. 10 shows a flowchart of the distance measuring device according to the second embodiment.
When reading the voltage signals v1 to v4 obtained by converting the output currents i1 to i4 from the light receiving unit, the distance calculation unit 43 sequentially turns on the switches 931 to 934 in the multiplexer 91 one by one to output the output currents i1 to i4. Selection is performed one by one (S101, S109, S117, S125). Then, the selected output currents i1 to i4 are input to the amplifier 51 and the A / D converter 53, respectively, converted into the voltage signals v1 to v4, and read (S105, S113, S121, S129).
As a result, the number of amplifier elements 511 to 514 and A / D converters 531 to 534 required in the first embodiment can be reduced, and the circuit can be reduced in size, cost and power consumption can be reduced. I do.
In the second embodiment, the number of times of light emission necessary for detecting an object at one time increases. However, since the light emission time per one time is about several μsec to several tens μsec, the amplifier element 51 and the A / D Reducing the number of converters 53 contributes to lower power consumption.
[0036]
FIG. 11 is a view showing an automatic faucet apparatus according to a third embodiment of the present invention. The automatic faucet device 152 includes the detecting means 2 and the valve 161 according to the present invention, which are provided in the flush 163 of the kitchen sink 167.
A water supply channel 171 through which hot and cold water from a hot and cold water supply device 169 flows is connected to the water washing 163, and a water outlet 165 is provided at a distal end, and a distance from an object such as a human body or an object is provided at a distal end or a base. The distance measuring sensor 3 according to the present invention is provided as measuring means for measuring the distance.
By configuring the automatic faucet device 152 in this manner, when the object is not within the detection range, the light emitted from the distance measurement sensor 3 is reflected by the sink 167 that specularly reflects the light, and the detection means 2 erroneously detects the valve. Can be opened and closed to prevent water spouting.
[Brief description of the drawings]
FIG. 1 is a basic configuration diagram of a distance measuring device according to the present invention.
FIG. 2 is an explanatory diagram of an operation of the distance measuring device according to the present invention.
FIG. 3 is a block configuration diagram of a distance measuring device according to the first embodiment of the present invention.
FIG. 4 is a graph showing a change in a voltage signal when a distance between a specular reflection object at a fixed position and an emission optical axis is measured.
FIG. 5 is an operation flowchart (part 1) of the distance measuring device 10.
FIG. 6 is a graph showing a displacement of a light condensing position when a distance between a specular reflection object at a certain position and an emission optical axis is measured.
FIG. 7 is an operation flowchart (No. 2) of the distance measuring device 10.
FIG. 8 is a diagram illustrating an example of an arrangement of a light emitting unit 11 and light receiving units 13a and 13b of the distance measuring sensor 3.
FIG. 9 is a block diagram of a detecting unit 2 of the distance measuring device according to the second embodiment of the present invention.
FIG. 10 shows a flowchart of a distance measuring device according to a second embodiment of the present invention.
FIG. 11 is a view showing an automatic faucet apparatus according to the present invention.
FIG. 12 is a view showing a conventional automatic faucet apparatus.
13A is a configuration diagram of a conventional distance measuring sensor, FIG. 13B is a diagram illustrating a position detection element 23, and FIG. 13C is a schematic configuration diagram of a controller 151.
FIG. 14 is a diagram (part 2) showing a conventional automatic faucet apparatus.
FIG. 15 is a diagram for explaining a difference in a light condensing position due to reflected light between a diffuse reflector and a specular reflector.
FIG. 16 shows a relationship between a change in an angle formed by a light emitting optical axis and a specular reflector 167 and a measurement distance.
[Explanation of symbols]
2. Detecting means (control unit)
3. Distance measuring sensor (ranging sensor)
5 Target object 10 Distance measuring device 11 Light emitting units 13a and 13b Light receiving unit 21 Light emitting side lenses 23a and 23b Light receiving side lens 31 Light emitting elements 33a and 33b Position detecting element 41 Detection possibility determination unit 43: distance calculation unit 91: switching means

Claims (8)

A light emitting unit that emits light toward the measured object;
A plurality of light receiving units that receive reflected light from the measured object and perform an output indicating a distance to the measured object according to an incident angle of the reflected light,
When the output values of at least two of the light receiving units are equal to or less than a predetermined distance, the distance measuring device for the object to be measured includes: a detection unit that detects the object to be measured. The distance measuring device according to claim 1, wherein at least one of the light receiving units is provided at a position opposite to any of the other light receiving units with respect to the light emitting unit. The distance measuring apparatus according to claim 1, wherein the detecting unit includes a distance calculating unit that calculates a distance to the measured object from an output value of the light receiving unit. The distance measuring device according to claim 1, wherein the light receiving unit includes a PSD sensor. The distance measuring apparatus according to any one of claims 1 to 4, further comprising switching means for selecting outputs of the plurality of light receiving units. A light emitting unit that emits light toward the measured object;
A plurality of light receiving units that receive reflected light from the object to be measured and perform an output indicating a distance to the object to be measured according to an incident angle of the reflected light,
A distance measuring sensor, wherein at least one of the light receiving units is provided at a position opposite to any of the other light receiving units with respect to the light emitting unit. The distance measuring sensor according to claim 6, wherein the light receiving unit includes a PSD sensor. An automatic faucet device comprising a valve control means for opening and closing a water supply channel based on a position detected by the distance measuring device according to claim 1.

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