JP2011080921A - Sanitary cleansing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sanitary cleansing apparatus with a pyroelectric sensor, capable of detecting entering of a person inside a bathroom, with high accuracy, even when the temperature inside the room is high. <P>SOLUTION: The sanitary cleansing apparatus 10 includes a pyroelectric sensor 52, which detects infrared ray radiated from a human body and outputs the detected result as a sensor output signal; an amplifying circuit 54, which amplifies the sensor output signal and outputs as an amplified output signal; an evaluation circuit 56, which evaluates the change in the presence/absence of a human body by determining whether the amplified output signal varies from a stationary value Vref of the amplified output signal, with a width which is larger than a fluctuation threshold Vth1 or a fluctuation threshold Vth2, and which outputs an evaluation result as an evaluation result signal; and a controller 42, which makes the sanitary cleansing apparatus 10 perform predetermined operations, when it is inferred that absence of human body is been changed into presence of a human body, based on the evaluation result signal. The evaluation circuit 56 further reduces the fluctuation thresholds Vth1, Vth2, as ambient temperature becomes higher. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a sanitary washing apparatus, and more particularly, to a sanitary washing apparatus having a pyroelectric sensor that can stably detect a person entering a room regardless of the temperature in a toilet room.

  Various automatic functions are installed in a sanitary washing device used by being attached to a toilet. One of the auto functions is a toilet lid automatic opening / closing function that automatically opens the toilet lid when a person enters the toilet room. As another automatic function, there is a power-saving toilet seat heating function that raises the temperature of the heated toilet seat to an appropriate temperature when a person enters the toilet room. When the person is not in the toilet room, this toilet seat heating function keeps the temperature of the toilet seat low to some extent, and when the person enters the room, the temperature of the toilet seat is rapidly increased to an appropriate temperature. It is intended to reduce energy consumption while maintaining the comfort of the user who uses. In order to realize such an automatic function, a sensor that detects with high accuracy that a person has entered the toilet room is essential.

  As such a sensor, a pyroelectric sensor is used in Japanese Patent Laid-Open No. 2007-32440 (Patent Document 1). This pyroelectric sensor is a sensor that detects the presence or absence of a human body that is a detection target by detecting infrared rays emitted from the human body. A pyroelectric sensor is suitable as a sensor for detecting a person entering a toilet room because the pyroelectric sensor has a wide direction of detection as a sensor and can detect the presence or absence of a human body over a wide area range.

  However, the pyroelectric sensor has a characteristic that it becomes difficult to detect a human body when the ambient temperature increases. This is because the pyroelectric sensor uses a temperature difference between the human body and its surroundings to detect the presence or absence of the human body, so the ambient temperature, that is, the temperature in the toilet room, is the human body temperature. As it approaches (typically 36 degrees), the temperature difference between the human body and the surroundings becomes smaller, making it difficult to detect the person entering the room.

  For this reason, when the interior of a toilet becomes hot, such as in summer, it is not possible to accurately detect a person's entry using a pyroelectric sensor, and the various auto functions described above may not operate normally. There was a problem. For this reason, in Japanese Patent Application Laid-Open No. 2009-58463 (Patent Document 2), the amplification factor of the amplifier circuit to which the sensor output signal that is the detection result of the pyroelectric sensor is input is increased as the ambient temperature increases. Even when the ambient temperature rises, an amplification output signal having a large amplitude is input to the determination circuit provided at the subsequent stage of the amplification circuit so that a person entering the room can be detected with high accuracy.

JP 2007-32440 A JP 2009-58463 A

  However, when the amplification factor of the amplifier circuit is increased as disclosed in Japanese Patent Application Laid-Open No. 2009-58463 (Patent Document 2), the characteristic also changes as can be seen from the amplification characteristic of the amplifier circuit shown in FIG. This change in the amplification characteristic occurs because the time constant of the amplifier circuit changes. In the example of FIG. 1, if the original amplification characteristic is represented by CHR1, the amplification characteristic after increasing the amplification factor is represented by CHR2. As can be seen by comparing the amplification characteristic CHR1 and the amplification characteristic CHR2, if the amplification factor is increased, the frequency band to be amplified is widened, and the sensor output signal in the frequency band that should not be amplified is large. It will be amplified by the amplification factor.

  For example, when a sensor output signal having a frequency lower than the frequency corresponding to 0.1 m / s is amplified and output to the determination circuit, the determination circuit automatically shifts the toilet lid from the open state to the closed state. The possibility of detecting a toilet lid at the time or detecting a curtain swaying in the wind increases. It is necessary to avoid such a disturbance from being erroneously detected that a person has entered the room as much as possible.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a sanitary washing device having a pyroelectric sensor that can accurately detect a person entering a room even when the temperature in the toilet room becomes high. And

  In order to solve the above problems, a sanitary washing device according to the present invention detects infrared rays radiated from a human body and outputs the detection result as a sensor output signal from the pyroelectric sensor and the pyroelectric sensor. The output sensor output signal is input, the sensor output signal is amplified and output as an amplified output signal, and the amplified output signal output from the amplifier circuit is input, and the amplified output signal However, it is determined whether or not there is a change in the presence or absence of a human body depending on whether or not the fluctuation value is larger than a fluctuation threshold from the steady value of the amplified output signal, and the determination result is output as a determination result signal. Circuit and the determination result signal output from the determination circuit are input, and based on the determination result signal, when it can be estimated that the human body has changed from no human body, To execute a predetermined operation sanitary washing apparatus, and a control unit, and wherein the decision circuit in accordance with the ambient temperature of the determination circuit is higher, to reduce the variation threshold, it is characterized.

  As a result, even when the ambient temperature of the judgment circuit, that is, the temperature in the toilet room where the sanitary washing device is installed, becomes high, the pyroelectric sensor is used to detect changes in the presence or absence of the human body more reliably. become able to. For this reason, even in a hot summer where the toilet room becomes hot, the sanitary washing apparatus can be caused to perform a predetermined operation that should be performed when the user enters the toilet room.

  In this case, a determination circuit may be configured that uses a temperature-sensitive resistance element whose resistance changes in accordance with the ambient temperature of the determination circuit, so that the variation threshold decreases as the ambient temperature increases. As described above, by using the temperature-sensitive resistance element, it is possible to easily configure a determination circuit in which the variation threshold value decreases as the ambient temperature of the determination circuit increases.

  In this case, the determination circuit uses two temperature-sensitive resistance elements having different resistance value change characteristics with respect to a change in ambient temperature, and a positive direction fluctuation threshold value that is a threshold value from the steady value to the positive direction in the fluctuation threshold value. And a minus direction variation threshold value that is a threshold value in the minus direction from the steady value in the variation threshold value. Thus, by using two temperature sensitive resistance elements having different characteristics, the variation threshold value can be determined with high accuracy.

  In these cases, for example, a thermistor resistance can be used for the temperature-sensitive resistance element. Since the thermistor resistance is a general-purpose component, it is easily available and inexpensive.

  The determination circuit includes a first resistance element connected between the first power source of the first voltage and the first node, the first node, and a second voltage lower than the first voltage. A first temperature sensitive resistance element connected between two power sources; a second temperature sensitive resistance element connected between the first power source and a second node; the second node; A first differential amplifier connected between the second power source and a second differential element; a non-inverting input terminal connected to the first node; and the amplified output signal input to the inverting input terminal; A second differential amplifier, wherein the amplified output signal is input to a non-inverting input terminal, and the inverting input terminal is connected to the second node; and from the first differential amplifier and the second differential amplifier The determination result signal may be output.

  With such a specific circuit configuration, the determination circuit can be configured. The fluctuation threshold value on the plus side from the steady value of the amplified output signal can be determined using the first temperature sensing resistor element, and the fluctuation threshold value on the minus side from the steady value of the amplified output signal can be determined by using the second temperature sensing resistor element. Since it can be determined using, the fluctuation threshold values on the plus side and the minus side can be defined so as to accurately change following the temperature change. For this reason, even if the temperature around the sanitary washing device increases, the presence or absence of a human body can be detected more reliably.

  According to the sanitary washing device of the present invention, it becomes possible to stably detect a person's entrance using a pyroelectric sensor regardless of the temperature in the toilet room in which the sanitary washing device is installed.

It is a figure which shows in graph an example of the change of the amplification characteristic of an amplifier circuit when the amplification factor of an amplifier circuit is changed. It is a side view (state before a person enters a toilet room) which shows the sanitary washing apparatus which concerns on one Embodiment of this invention, and the toilet bowl to which this sanitary washing apparatus was attached. It is a figure for demonstrating an example of a structure of the sanitary washing apparatus of FIG. 2 as a functional block. It is a side view (state after a person enters a toilet room) which shows a sanitary washing device concerning one embodiment of the present invention, and a toilet bowl in which this sanitary washing device was attached. It is a figure for demonstrating an example of the internal structure of the human body detection unit in the sanitary washing apparatus shown in FIG. 3 as a functional block. FIG. 6 is a circuit diagram illustrating an example of a specific circuit configuration of a determination circuit in the human body detection unit illustrated in FIG. 5. FIG. 7 is a graph showing an example of changes in thermistor resistances Rth1 and Rth2 and voltage V1 with respect to temperature changes in the determination circuit of FIG. FIG. 7 is a graph showing an example of changes in thermistor resistances Rth1, Rth2 and voltage V2 with respect to temperature changes in the determination circuit of FIG. FIG. 5 is a graph showing an example of changes in an upper threshold voltage V1, a lower threshold voltage V2, and an amplified output signal when the ambient temperature is 20 ° C. FIG. 7 is a graph showing an example of changes in the upper threshold voltage V1, the lower threshold voltage V2, and the voltage of the amplified output signal when the ambient temperature is 35 ° C. A plan view of a person entering the toilet room with a sanitary washing device incorporating a pyroelectric sensor in a direction in which a minus area is formed on the front side and a plus area is formed on the back side. It is. FIG. 12 is a graph showing an example of voltage variation of an amplified output signal corresponding to FIG. 11. A plan view of a person entering the toilet room with a sanitary washing device incorporating a pyroelectric sensor in a direction in which a plus area is formed on the front side and a minus area is formed on the back side. It is. It is a figure which shows an example of the fluctuation | variation of the voltage of the amplified output signal corresponding to FIG. 13 as a graph.

  One embodiment of the present invention is provided with a determination circuit that determines whether or not there is a change in the presence or absence of a human body depending on whether or not the amplified output signal output from the amplifier circuit has changed more than a fluctuation threshold from a steady value. In the sanitary washing device, the fluctuation threshold is reduced as the ambient temperature of the judgment circuit increases, so that a change in the presence or absence of a human body can be accurately detected even at a high temperature, and a person enters the toilet room. This can be detected with high accuracy. More details will be described below.

  FIG. 2 is a side view showing a sanitary washing device 10 according to an embodiment of the present invention and a toilet 20 to which the sanitary washing device 10 is attached. As shown in FIG. 2, the sanitary washing device 10 according to this embodiment includes a sanitary washing device body 12, a toilet lid 14, and a toilet seat 16. The sanitary washing apparatus body 12 has a built-in control function for controlling the operation of the sanitary washing apparatus 10. The toilet lid 14 and the toilet seat 16 are rotatably connected to the sanitary washing device body 12. The sanitary washing device 10 and the toilet bowl 20 are provided in a toilet room.

  FIG. 3 is a diagram illustrating an example of the configuration of the sanitary washing device 10 as a functional block. As shown in FIG. 3, the sanitary washing device 10 according to this embodiment includes a washing function unit 30, a toilet lid opening / closing unit 32, a toilet seat opening / closing unit 34, a toilet seat heating unit 36, an indoor heating unit 38, A human body detection unit 40 and a control unit 42 are provided. The control unit 42 includes, for example, a CPU (Central Processing Unit), and various types of functions for the cleaning function unit 30, the toilet lid opening / closing unit 32, the toilet seat opening / closing unit 34, the toilet seat heating unit 36, and the indoor heating unit 38 are provided. Execute the control.

  The cleaning function unit 30 has a function of discharging the cleaning water from the discharge nozzle toward the local part of the user sitting on the toilet seat 16 and cleaning the local part of the user. In addition, the cleaning function unit 30 has a function of heating the tap water supplied to the sanitary cleaning device 10 to make it warm water, and discharges the cleaning water that has become hot water according to the setting of the user. It is also possible to discharge from the nozzle. Therefore, the term “water” in the present embodiment should be interpreted as including not only cold water but also heated hot water.

  The toilet lid opening / closing unit 32 is a functional unit that automatically opens and closes the toilet lid 14 provided in the sanitary washing device 10. In particular, in this embodiment, when the human body detection unit 40 detects that a person has entered the toilet room, the toilet lid opening / closing unit 32 automatically shifts the toilet lid 14 from the closed state to the open state. That is, when the human body detection unit 40 detects a person entering the toilet room, the toilet lid opening / closing unit 32 opens the toilet lid 14 in the closed state as shown in FIG. 2, and opens as shown in FIG. The state is shifted to a state where the user can use the sanitary washing device 10. The toilet seat opening / closing unit 34 is a functional unit that automatically opens and closes the toilet seat 16 provided in the sanitary washing device 10.

  The toilet seat heating unit 36 is a functional unit that warms the toilet seat 16 according to the setting made by the user. In particular, in the present embodiment, when there is no person in the toilet room, the toilet seat 16 is held at a temperature lower than the setting, and when the human body detection unit 40 detects that a person has entered the toilet room, The toilet seat heating unit 36 raises the temperature of the toilet seat 16 to bring the temperature of the toilet seat 16 to a set temperature. By doing so, power consumption is reduced while maintaining the comfort of the user who uses the toilet seat 16. The indoor heating unit 38 is a functional unit that heats the toilet room in which the sanitary washing device 10 is installed.

  FIG. 5 is a block diagram illustrating an example of the internal configuration of the human body detection unit 40 according to the present embodiment. As shown in FIG. 5, the human body detection unit 40 according to this embodiment includes a lens 50, a pyroelectric sensor 52, an amplification circuit 54, and a determination circuit 56.

  The pyroelectric sensor 52 detects infrared rays emitted from the human body via the lens 50 and outputs the detection result to the amplifier circuit 54 as a sensor output signal. That is, the pyroelectric sensor 52 detects a temperature change in the detection target range by using infrared rays, converts it into an electric signal based on the pyroelectric action, and outputs it as a sensor output signal. In the present embodiment, the sensor output signal is a voltage signal, and when there is no person entering or leaving the toilet room, the sensor output signal is configured to have a steady value that is a predetermined voltage, but changes to the presence or absence of a human body. If there is, the voltage of the sensor output signal fluctuates from the steady value to the plus direction and the minus direction.

  A sensor output signal output from the pyroelectric sensor 52 is input to the amplifier circuit 54. The amplifier circuit 54 amplifies the amplitude of the sensor output signal, which is a voltage signal, and outputs the amplified signal to the determination circuit 56 as an amplified output signal.

  The amplified output signal is input to the determination circuit 56, and it is determined whether or not there is a change in the presence or absence of a human body in the toilet room, depending on whether or not the amplified output signal has changed from a steady value to a value larger than the fluctuation threshold. Then, the determination circuit 56 outputs the determination result to the control unit 42 as a determination result signal.

  The control unit 42 determines whether a person has entered the toilet room based on the determination result signal input from the determination circuit 56, and if it can be estimated that the person has entered the sanitary washing apparatus 10. On the other hand, a predetermined operation is executed. Specifically, as described above, the control unit 42 issues an activation command for opening the toilet lid 14 to the toilet lid opening / closing unit 32. Further, the control unit 42 issues an activation command for raising the temperature of the toilet seat 16 to the toilet seat heating unit 36.

  FIG. 6 is a diagram illustrating an example of a specific circuit configuration of the determination circuit 56 according to the present embodiment. As shown in FIG. 6, the determination circuit 56 according to the present embodiment includes resistors R1 and R2, thermistor resistors Rth1 and Rth2, and differential amplifiers OP1 and OP2. The resistors R1 and R2 have a predetermined fixed resistance value. The thermistor resistances Rth1 and Rth2 are an example of a temperature-sensitive resistance element whose resistance value changes as the ambient temperature changes.

  The resistor R1 is connected between the power supply of the voltage V0 and the node ND1, and the thermistor resistor Rth1 is connected between the node ND1 and the ground. That is, the resistor R1 and the thermistor resistor Rth1 are connected in series between the power supply of the voltage V0 and the ground. In the present embodiment, for example, a power supply of 5V is used, so the voltage V0 is 5V.

  The thermistor resistor Rth2 is connected between the power supply of the voltage V0 and the node ND2, and the resistor R2 is connected between the node ND2 and the ground. That is, the thermistor resistance Rth2 and the resistance R2 are connected in series between the power supply of the voltage V0 and the ground. In other words, a path including the resistor R1 and the thermistor resistor Rth1 and a path including the thermistor resistor Rth2 and the resistor R2 are formed in parallel between the power supply of the voltage V0 and the ground.

  When the voltage at the node ND1 is V1, the voltage V1 is input to the non-inverting input terminal of the differential amplifier OP1. The amplified output signal output from the amplifier circuit 54 is input to the inverting input terminal of the differential amplifier OP1. The differential amplifier OP1 outputs a determination result signal of 0V or 5V according to the difference between the voltage V1 and the voltage of the amplified output signal. That is, when the voltage of the amplified output signal is lower than the voltage V1, a determination result signal of 5V is output, and when the voltage of the amplified output signal is higher than the voltage V1, a determination result signal of 0V is output. .

  On the other hand, when the voltage of the node ND2 is V2, this voltage V2 is input to the inverting input terminal of the differential amplifier OP2. The amplified output signal output from the amplifier circuit 54 is input to the non-inverting input terminal of the differential amplifier OP2. The differential amplifier OP2 outputs a determination result signal of 0V or 5V according to the difference between the voltage V2 and the voltage of the amplified output signal. That is, when the voltage of the amplified output signal is higher than the voltage V2, a determination result signal of 5V is output, and when the voltage of the amplified output signal is lower than the voltage V2, a determination result signal of 0V is output. .

  As will be described in detail later, in the present embodiment, the voltage V2 is set to be lower than the voltage V1. For this reason, the voltage V1 constitutes an upper threshold value, and the voltage V2 constitutes a lower threshold value. The determination circuit 56 outputs a 5V determination result signal when the voltage of the input amplified output signal is between the upper threshold voltage V1 and the lower threshold voltage V2. When the voltage of the amplified output signal is larger than the upper threshold voltage V1 or smaller than the lower threshold voltage V2, a low-level determination result signal is output. That is, in the present embodiment, the determination result signal is a digital signal composed of a low level (0 V) or a high level (5 V).

  According to the circuit configuration of FIG. 6, the voltage V1 can be expressed by V1 = (V0 × Rth1) / (R1 + Rth1), and the voltage V2 can be expressed by V2 = (V0 × R2) / (R2 + Rth2). it can. Since the thermistor resistances Rth1 and Rth2 are temperature-sensitive resistance elements whose resistance values change depending on the temperature, the voltage values of the voltages V1 and V2 also change depending on the ambient temperature of the determination circuit 56.

  Here, the temperature around the determination circuit 56 is directly the temperature inside the determination circuit 56 provided with the thermistor resistances Rth1 and Rth2, but substantially the temperature around the determination circuit 56 is substantially the same. This means that the temperature is detected, that is, the temperature (air temperature) in the toilet room that the pyroelectric sensor 52 is trying to detect.

  According to the circuit configuration of the determination circuit 56 shown in FIG. 6, an example of the first power source of the first voltage of the present invention is a power source of the voltage V0, and an example of the second power source of the second voltage of the present invention is It is a ground, an example of the first resistance element of the present invention is the resistor R1, an example of the first temperature sensitive resistance element of the present invention is the thermistor resistance Rth1, and an example of the second resistance element of the present invention is The resistor R2 is an example of the second temperature sensitive resistor element of the present invention, the thermistor resistor Rth2, the example of the first differential amplifier of the present invention is the differential amplifier OP1, and the second differential element of the present invention. An example of the amplifier is a differential amplifier OP2.

  FIG. 7 is a graph showing the relationship between the ambient temperature and the voltage V1 and the relationship between the ambient temperature and the resistance values of the thermistor resistors Rth1 and Rth2 in the present embodiment. FIG. 8 is a graph showing a relationship between the ambient temperature and the voltage V2 and a relationship between the ambient temperature and the resistance values of the thermistor resistors Rth1 and Rth2 in the present embodiment.

  As can be seen from FIGS. 7 and 8, in the present embodiment, the thermistor resistances Rth1 and Rth2 have a characteristic that the resistance value decreases as the ambient temperature increases. For this reason, as the ambient temperature increases, the voltage V1 decreases and the voltage V2 increases.

  Furthermore, in the present embodiment, the ratio at which the voltage V1 decreases and the ratio at which the voltage V2 increases are set to be equal. That is, the magnitude at which the voltage V1 decreases as the temperature rises is set to be equal to the magnitude at which the voltage V2 increases. This means that the slope a1 of the voltage V1 in the negative direction and the slope a2 of the voltage V2 in the positive direction are equal when viewed in the graphs of FIGS.

  In order to realize such temperature characteristics of the voltages V1 and V2, in this embodiment, the thermistor resistances Rth1 and Rth2 satisfy the condition that Rth1 = (ab−Rth2) / (cd−Rth2). It is selected to satisfy. However, a = (V0-2 × Vref) × R1 × R2, b = 2 × Vref × R1, c = 2 × (Vref−V0) × R2, d = V0-2 × Vref, and Vref is amplified. The steady value of the voltage of the output signal is shown.

  The change of the voltages V1 and V2 with respect to the temperature causes a change in the determination criterion in the determination circuit 56 as illustrated in FIGS. FIG. 9 is a diagram illustrating an example of the values of the voltages V1 and V2 when the ambient temperature is 20 ° C. and the waveform of the amplified output signal input to the determination circuit 56. FIG. 10 is a diagram illustrating an example of the values of the voltages V1 and V2 when the ambient temperature is 35 ° C. and the waveform of the amplified output signal input to the determination circuit 56. 9 and 10 show an example of the waveform of the amplified output signal when the pyroelectric sensor 52 detects a change from the absence of a human body to the presence of a human body.

  As shown in FIG. 9, when the ambient temperature is 20 ° C., the amplitude of the amplified output signal input to the determination circuit 56 when the human body changes from no human body is relatively large. In other words, the amplified output signal largely fluctuates from the steady value with the change from the absence of the human body to the presence of the human body. This variation includes a variation from the steady value to the plus direction and a variation from the steady value to the minus direction.

  Then, the determination circuit 56 determines that the determination result signal indicating that the human body has changed from the absence of the human body to the presence of the human body while the voltage of the amplified output signal is larger than the upper threshold voltage V1 due to the fluctuation in the plus direction, A level judgment result signal is output.

  Here, if the variation threshold value Vth1 in the plus direction in FIG. 9 is Vth1 = (voltage V1) − (steady value Vref of the amplified output signal), the determination circuit 56 determines that the voltage of the input amplified output signal is It is determined whether the voltage of the amplified output signal fluctuates in the plus direction with a width larger than the fluctuation threshold Vth1, and when the voltage of the amplified output signal fluctuates in the plus direction with a width larger than the fluctuation threshold Vth1, This means that the presence or absence has changed.

  Similarly, when the voltage of the amplified output signal becomes smaller than the lower threshold voltage V2 due to fluctuation in the negative direction, the determination circuit 56 determines that the determination result signal indicates that the human body has changed from the absence of the human body, that is, the presence of the human body. Outputs a low level judgment result signal.

  Here, if the fluctuation threshold value Vth2 in the negative direction in FIG. 9 is Vth2 = (steady value Vref of the amplified output signal) − (voltage V2), the determination circuit 56 determines that the voltage of the input amplified output signal is It is determined whether or not the voltage of the amplified output signal fluctuates in the negative direction with a width larger than the fluctuation threshold Vth2, and when the voltage of the amplified output signal fluctuates in the negative direction with a width larger than the fluctuation threshold Vth2, This means that the presence or absence has changed.

  On the other hand, as shown in FIG. 10, when the ambient temperature is 35 ° C., the amplitude of the amplified output signal input to the determination circuit 56 when the human body is changed from the absence is relatively small. That is, the amplitude of the amplified output signal accompanying the change from the absence of the human body to the presence of the human body is smaller than that in the case where the ambient temperature is 20 ° C. For this reason, the voltage of the amplified output signal varies slightly from the steady value. As for this fluctuation. As in the case of 20 ° C., there is a fluctuation from the steady value to the plus direction and a fluctuation from the steady value to the minus direction.

  Then, the determination circuit 56 determines that a determination result signal indicating that the human body has changed from the absence of the human body to the presence of the human body when the voltage of the amplified output signal becomes larger than the voltage V1 due to the fluctuation in the plus direction, that is, the determination result of the low level. Output a signal. However, as shown in FIG. 7, the upper threshold voltage V1 at 35 ° C. is lower than the voltage V1 at 20 ° C. Therefore, the fluctuation threshold value Vth1 in the positive direction in FIG. 10 is smaller than the fluctuation threshold value Vth1 in FIG.

  The determination circuit 56 determines whether or not the voltage of the input amplified output signal has fluctuated in the positive direction with a width larger than the fluctuation threshold Vth1, and the voltage of the amplified output signal is changed from the steady value to the fluctuation threshold Vth1. When the signal fluctuates in the plus direction with a large width, a low-level determination result signal indicating that there is a change in the presence or absence of the human body is output. For this reason, when the ambient temperature is 35 ° C., it can be detected even if the fluctuation of the voltage of the amplified output signal in the positive direction is small compared to the case of 20 ° C.

  Similarly, when the voltage of the amplified output signal becomes lower than the voltage V2 due to a change in the minus direction, the determination circuit 56 determines the determination result signal indicating that the human body has changed from the absence of the human body, that is, the low-level determination. Output the result signal. However, as shown in FIG. 8, the lower threshold voltage V2 at 35 ° C. is higher than the voltage V2 at 20 ° C. Therefore, the fluctuation threshold value Vth2 in the negative direction in FIG. 10 is smaller than the fluctuation threshold value Vth2 in FIG.

  The determination circuit 56 determines whether or not the voltage of the input amplified output signal has fluctuated in the negative direction with a width larger than the fluctuation threshold Vth2, and the voltage of the amplified output signal is changed from the steady value to the fluctuation threshold Vth2. When a fluctuation occurs in the minus direction with a large width, a low-level determination result signal is output, which means that it is determined that the presence or absence of the human body has changed. For this reason, when the ambient temperature is 35 ° C., it can be detected even if the fluctuation of the voltage of the amplified output signal in the minus direction is small compared to the case of 20 ° C.

  Further, as can be seen from these facts, in the determination circuit 56 of the present embodiment, even when the voltage of the amplified output signal does not fluctuate greatly in the minus direction but fluctuates only in the plus direction, the fluctuation threshold Vth1 When it fluctuates with a larger range, a low-level determination result signal is output. Even if the voltage of the amplified output signal does not fluctuate greatly in the positive direction but fluctuates only in the negative direction, a low-level determination result signal is output when it fluctuates with a width greater than the fluctuation threshold Vth2. To do. That is, according to the determination circuit 56 according to the present embodiment, even when the voltage of the amplified output signal greatly fluctuates only in one of the plus direction and the minus direction, this can be detected. In this embodiment, as described above, even when the voltage of the amplified output signal greatly fluctuates only in one of the plus direction and the minus direction, the determination circuit 56 detects this and there is a change in the presence or absence of a person. This is because the voltage of the amplified output signal often oscillates only in one of the plus direction and the minus direction due to the characteristics of a general pyroelectric sensor 52.

  The reason for this will be described below with reference to FIGS. FIG. 11 is a plan view for explaining how the pyroelectric sensor 52 is used to detect a change in the presence or absence of a human body in the toilet room 60, and a negative floating charge in the pyroelectric sensor 52 on the front side of the person entering the room. A layout is shown in which a minus area 62 for performing detection is provided, and a plus area 64 for performing detection with positive floating charges in the pyroelectric sensor 52 is provided on the back side of the person entering the room. FIG. 12 is a graph showing an example of a change in voltage of the amplified output signal when a person enters the toilet room 60 of FIG.

  FIG. 13 is a plan view for explaining a state in which the presence or absence of a human body in the toilet room 60 is detected using the pyroelectric sensor 52. Detection is performed by positive floating charges in the pyroelectric sensor 52 on the front side of the person entering the room. A layout is shown in which a plus area 64 is provided, and a minus area 62 is provided on the far side of the person's entrance direction in which the pyroelectric sensor 52 detects negative floating charges. FIG. 14 is a graph showing an example of a change in the voltage of the amplified output signal when a person enters the toilet room 60 of FIG.

  In the case of the layout shown in FIG. 11, when a person enters the toilet room 60, first, the user enters the minus area 62. Therefore, a large amount of negative floating charge is generated by the pyroelectric sensor 52, and the sensor output signal from the pyroelectric sensor 52 fluctuates greatly in the negative direction. Therefore, as shown in FIG. 12, the voltage of the amplified output signal is Also fluctuates significantly in the negative direction. Thereafter, the person enters the center of the toilet room 60 and enters the plus area 64. At this time, a large amount of positive floating charge is generated in the pyroelectric sensor 52, but it is canceled out by the negative floating charge that has been generated so far, and the sensor output signal from the pyroelectric sensor 52 is positive. Therefore, the voltage of the amplified output signal does not fluctuate significantly in the positive direction as shown in FIG.

  On the other hand, in the layout shown in FIG. 13, when a person enters the toilet room 60, first, the user enters the plus area 64. Therefore, a large amount of positive floating charge is generated by the pyroelectric sensor 52, and the sensor output signal from the pyroelectric sensor 52 fluctuates greatly in the positive direction. Therefore, as shown in FIG. 14, the voltage of the amplified output signal Also fluctuates significantly in the positive direction. Thereafter, the person enters the center of the toilet room 60 and enters the minus area 62. At this time, in the pyroelectric sensor 52, a large amount of negative floating charge is generated, but it is canceled by the positive floating charge generated so far, and the sensor output signal from the pyroelectric sensor 52 is negative. Therefore, the voltage of the amplified output signal does not fluctuate so much in the negative direction as shown in FIG.

  Due to the characteristics of the pyroelectric sensor 52, in the present embodiment, the determination circuit 56 is configured by making the difference between the fluctuation thresholds Vth1 and Vth2 that fluctuate due to changes in ambient temperature and the steady value Vref the same. Even if the voltage of the amplified output signal fluctuates in the plus direction from the steady value with a width greater than the fluctuation threshold Vth1, the presence or absence of the human body in the toilet room 60 changes regardless of whether it fluctuates in the minus direction with a width greater than the fluctuation threshold Vth2. It is possible to judge that there was.

  As described above, the determination circuit 56 detects both the positive direction fluctuation and the negative direction fluctuation of the voltage of the amplified output signal, after all, in the negative area 62 of the pyroelectric sensor 52. This is because it cannot be specified in advance whether the positional relationship between the positive area 64 and the positive area 64 is the positional relationship in FIG. 11 or the positional relationship in FIG. That is, when the pyroelectric sensor 52 is incorporated into the sanitary washing device 10, there are two orientations of the pyroelectric sensor 52: the orientation of FIG. 11 and the orientation of FIG. However, the pyroelectric sensor 52 has a configuration in which it is impossible to identify which is the minus area 62 and which is the plus area 64 as the component orientation. For this reason, even when the pyroelectric sensor 52 is attached to the sanitary washing device 10 in the orientation of FIG. 11, or even when the pyroelectric sensor 52 is attached to the sanitary washing device 10 in the orientation of FIG. Thus, it is possible to appropriately determine the person entering the toilet room 60.

  In addition, due to the characteristics of the pyroelectric sensor 52, when a person leaves the toilet room 60, the presence or absence of a person also varies, so this is usually detected and the voltage of the amplified output signal is also corresponding. It will show the amplitude. However, in this case, only a short time has elapsed since some operation was performed on the sanitary washing device 10, and the toilet lid 14 that has been closed by the toilet lid opening / closing unit 32 is opened. Since there is some precondition that only a short time has passed since the transition, the pyroelectric sensor 52 detects that the person has left the room, and the determination circuit 56 has changed the presence or absence of the human body. Even if the low-level determination result signal shown is output to the control unit 42, the sanitary washing device 10 can be designed so as not to operate erroneously. Therefore, even when the determination result signal output from the determination circuit 56 indicates that there is a change in the presence or absence of the human body, the control unit 42 takes this determination result signal into consideration that there is no human body. The opening operation of the toilet lid 14 and the temperature raising operation of the toilet seat 16 described above may be executed only when it can be estimated that this means that the human body has changed.

  As described above, according to the sanitary washing device 10 according to the present embodiment, the fluctuation thresholds Vth1 and Vth2 are decreased as the temperature around the determination circuit 56 increases, so that the temperature in the toilet room 60 increases. Even if it becomes, it will become possible to detect that the user entered the toilet room 60 with higher accuracy. For this reason, the control part 42 can make the sanitary washing apparatus 10 perform the operation | movement which should be performed with a user's entrance into a room with higher precision.

  In addition, since the thermistor resistors Rth1 and Rth2 having high versatility are used as the temperature-sensitive resistance elements constituting the determination circuit 56, the determination circuit 56 can be realized at low cost.

  Furthermore, since the fluctuation threshold value Vth1 in the positive direction from the steady value Vref is defined by the resistor R1 and the thermistor resistance Rth1, the fluctuation threshold value Vth2 in the negative direction from the steady value Vref is defined by the resistance R2 and the thermistor resistance Rth2. The fluctuation threshold value Vth1 and the fluctuation threshold value Vth2 can be changed with high accuracy with respect to changes in the ambient temperature. In particular, in the present embodiment, since it is necessary to make the magnitude of the change of the fluctuation threshold Vth1 with respect to the temperature change equal to the magnitude of the fluctuation threshold Vth2, the fluctuation thresholds Vth1 and Vth2 can be individually defined. High accuracy and ease of design can be ensured.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation is possible. For example, in the above-described embodiment, the determination circuit 56 detects both a change in the positive direction and a change in the negative direction of the voltage of the amplified output signal. It is. That is, if the orientation when attaching the pyroelectric sensor 52 to the sanitary washing device 10 can be limited to the orientation shown in FIG. 11 or the orientation shown in FIG. It is also possible to determine that there is a change in the presence or absence of the human body in the toilet room 60 based only on the minus direction fluctuation.

  Specifically, first, some information is added to the components of the pyroelectric sensor 52 in order to specify the directions of the minus area 62 and the plus area 64 of the pyroelectric sensor 52. This information may be a so-called mark for specifying the direction in which the minus area 62 and the plus area 64 are formed.

  If the pyroelectric sensor 52 is attached to the sanitary washing device 10 so that the minus area 62 and the plus area 64 are formed in the direction of FIG. Only when the voltage of the amplified output signal fluctuates more than the fluctuation threshold Vth2 in the minus direction from the steady value Vref, it can be determined that there is a change in the presence or absence of the human body in the toilet room 60. There is no need to do.

  On the contrary, in the manufacturing process of the sanitary washing device 10, if the pyroelectric sensor 52 is attached to the sanitary washing device 10 so that the minus area 62 and the plus area 64 are formed in the direction of FIG. Can be determined that there is a change in the presence or absence of the human body in the toilet room 60 only when the voltage of the amplified output signal fluctuates more than the fluctuation threshold Vth1 in the plus direction from the steady value Vref. There is no need to make a decision.

DESCRIPTION OF SYMBOLS 10 Sanitary washing apparatus 12 Sanitary washing apparatus main body 14 Toilet lid 16 Toilet seat 20 Toilet bowl 30 Cleaning function part 32 Toilet lid opening / closing unit 34 Toilet seat opening / closing unit 36 Toilet seat heating unit 38 Indoor heating unit 40 Human body detection unit 42 Control part 50 Lens 52 Pyroelectric Sensor 54 Amplifying circuit 56 Judging circuit R1, R2 Resistance Rth1, Rth2 Thermistor resistance OP1, OP2 Differential amplifier

Claims (5)

A pyroelectric sensor that detects infrared rays emitted from the human body and outputs the detection result as a sensor output signal;
The sensor output signal output from the pyroelectric sensor is input, the sensor output signal is amplified and output as an amplified output signal, and an amplification circuit;
Whether the presence or absence of a human body has changed depending on whether the amplified output signal output from the amplifier circuit is input and the amplified output signal has fluctuated from a steady value of the amplified output signal by a width larger than a fluctuation threshold. A determination circuit that determines whether or not and outputs the determination result as a determination result signal;
The determination result signal output from the determination circuit is input, and based on the determination result signal, when it can be estimated that the human body has changed from no human body, the sanitary washing device is caused to execute a predetermined operation. A control unit;
With
The sanitary washing apparatus, wherein the determination circuit decreases the fluctuation threshold as the temperature around the determination circuit increases.   By using a temperature-sensitive resistance element whose resistance changes according to the ambient temperature of the determination circuit, the determination circuit is configured such that the variation threshold decreases as the ambient temperature of the determination circuit increases. The sanitary washing device according to claim 1, wherein   The determination circuit uses two temperature-sensitive resistance elements having different resistance value change characteristics with respect to a change in ambient temperature, and uses a positive direction variation threshold value that is a threshold value in the plus direction from the steady value. The sanitary washing device according to claim 2, wherein a negative direction fluctuation threshold value that is a threshold value in the negative direction from the steady value in the fluctuation threshold value is defined.   The sanitary washing device according to claim 2 or 3, wherein the temperature-sensitive resistance element is a thermistor resistance. The determination circuit includes:
A first resistance element connected between a first power supply of a first voltage and a first node;
A first temperature-sensitive resistance element connected between the first node and a second power source having a second voltage lower than the first voltage;
A second temperature-sensitive resistance element connected between the first power source and a second node;
A second resistance element connected between the second node and the second power source;
A first differential amplifier having a non-inverting input terminal connected to the first node and the amplified output signal being input to the inverting input terminal;
A second differential amplifier, wherein the amplified output signal is input to a non-inverting input terminal, and the inverting input terminal is connected to the second node;
With
The sanitary washing device according to any one of claims 1 to 4, wherein the determination result signal is output from the first differential amplifier and the second differential amplifier.

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