JP2876387B2 - Seating detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seat detection device,
In particular, the present invention relates to a seating detection device that detects seating by detecting infrared light reflected on a human body.

[0002]

2. Description of the Related Art In general, a toilet seat type automatic sanitary washing device used in a toilet is provided with a seat detection device for detecting whether a user is sitting on a toilet seat or not, and for example, deodorizing in response to the detection of seating. Automatically controls various functions provided in the automatic sanitary washing device, such as starting to drive the device and accepting various operation switches, and stopping receiving water, deodorizing device, and various operation switches in response to non-seating detection It is something to do.

FIGS. 7A and 7B are external views showing a toilet seat type automatic sanitary washing apparatus, wherein FIG. 7A is a plan view, FIG. 7B is a front view, and 71 is an infrared sensor part of a seating detection device. It is. FIGS. 8A and 8B are explanatory diagrams showing an infrared sensor unit. FIG. 8A is a front view, and FIG. 8B is a cross-sectional view showing a state in which the infrared sensor unit is attached. In FIG. A light-receiving sensor 82 for detecting light reception, a holder 83 for covering the LED 81 and the light-receiving sensor 82 for removing internal reflected light, and an infrared sensor portion composed of a substrate 85, a filter 86 for cutting disturbance light, and a case 87 Reference numeral 88 denotes a human body of a user sitting on the automatic sanitary washing device. Now, the infrared light output from the LED 81 passes through the filter 86 and then passes through the human body 8.
8, a part of the light is reflected, passes through the filter 86 again, and is detected by the light receiving sensor 82.

Conventionally, in this type of seating detection device, in order to detect a user's seating, an infrared ray is always output from the LED 81, and the amount of the infrared ray detected by the light receiving sensor 82 is converted into a voltage signal. If the value is equal to or more than the reference value, it is determined that the user is seated. FIG. 9 is a timing chart showing a detection operation performed by the conventional seating detection device, where 91 is a detection signal indicating the amount of infrared light detected by the light receiving sensor 82, 92 is a comparison output signal between the detection signal 91 and a predetermined voltage, 93 is a delay output based on the comparison output signal 92,
Reference numerals 95 to 97 denote noises generated in the comparison output signal 92.

When the user is seated at time T ₀ , the light receiving sensor 82 outputs the light from the LED 81 to the human body 88.
Receives the infrared light reflected by the detector, and outputs a detection signal 91 indicating the light amount. Here, at the time of the seating operation, the LED 8
Since the position of the human body 88 is not constant with respect to
The reflection direction of the infrared light radiated to the light 8 is also uncertain, and cannot be accurately detected by the light receiving sensor 82.
Fluctuates above and below the reference value, and a pulse-like noise 95 is generated in the comparison output signal 92. This also means that when the user changes the sitting position or posture at time T ₁ , or when the user is not seated at time T ₂ , similar pulse noises 96 and 97 are generated in the comparison output signal 92. Thus, it is impossible to use such an unstable comparison output signal 92 as it is as a seating signal indicating seating / non-seat.

As a method for solving such a problem, when the comparison output signal 92 is stably output for a certain period,
A method of determining whether the seat is sitting or not is considered. This means that when a certain period t _d the output level of the comparator output signals 92, for example, by providing a means for detecting continuously a few seconds, which is continuously output is one of the level over a time t _d, the seating -The non-seat is determined and output. If a noise 95 is generated at the time of sitting (time T ₀ ), clocking is started from the time when the noise 95 disappears, and the level indicating the seating of the comparison output signal 92 is continuously detected for the time t _d. is the first time it is assumed that the delayed signal 93 indicating the sitting determination is output if the changes in sitting position and orientation at time T _1, or even when unseated at time T _2, by performing a relatively stable sitting determination Becomes possible.

[0007]

Therefore, in such a conventional seating detection device, the seating determination is performed for another few seconds (time t _d ) after the output level of the comparison output signal 92 is stabilized from the actual seating or non-seating. In an automatic sanitary washing device, the control of various functions, such as the start of reception of various operation switches and driving of the deodorizing device, or the stop of water discharge when not seated, is delayed in an automatic sanitary washing device. There is a problem that this may cause a problem. The present invention is intended to solve such a problem, and it is possible to perform a seating determination in a shorter time, and when a position of a human body is not constant or disturbance light is irradiated on a sensor unit. It is an object of the present invention to provide a seating detection device capable of obtaining a stable output even in a case.

[0008]

In order to achieve the above object, a seating detecting device according to the present invention comprises a transmitting means for outputting pulsed infrared rays based on a transmitting pulse signal having a predetermined period and width; Receiving means for detecting a part of the infrared light reflected by the user's body and outputting it as a received pulse signal; counting period generating means for outputting a reset signal indicating a pulse counting period at predetermined time intervals; and transmitting means And a transmission pulse counting means for initializing the number of transmission pulses based on the reset signal, and counting and outputting the number of reception pulses output from the receiving means, and receiving the number of pulses based on the reset signal. Receiving pulse counting means for initializing the number of pulses, and a pulse indicating a ratio of the number of receiving pulses to the number of transmitting pulses in the pulse counting period And efficiency out, Han seated and unseated
By comparing with two thresholds indicating the fixed condition,
A comparison / determination unit that determines whether the vehicle is seated or not. The receiving means, met those outputted in synchronization with the period and the transmission pulse signal of the detected pulse signal
And the width is within the allowable range of the transmission pulse signal width
And a pulse judging means for outputting the signal as a regular reception pulse signal. Further, the comparison determination means determines that the driver is seated when the pulse detection efficiency is equal to or greater than the first threshold, and the pulse detection efficiency is equal to or less than a second threshold smaller than the first threshold. Is determined to be non-seated.

[0009]

Accordingly, the transmitting means outputs pulsed infrared light based on a transmission pulse signal having a predetermined period and width, and the receiving means detects a part of the reflected light reflected by the user's body among the infrared light. The received pulse signal is output as a received pulse signal, the number of transmitted pulses output from the transmitting means is counted and output by the transmitted pulse counting means, and the number of received pulses output from the receiving means within the pulse counting period is counted and output by the received pulse counting means. Pulse detection efficiency indicating the ratio of the number of received pulses to the number of transmitted pulses in the pulse counting period by the comparison determination means ,
The two threshold values indicating the non-seat determination condition are compared.
Then, a determination of sitting / non-seat is made. Further, the pulse determination means of the receiving means, which is output during a period synchronized with the transmission pulse signal among the detected pulse signals ,
A pulse whose width is within the allowable range of the transmission pulse signal width is output as a normal reception pulse signal. Furthermore, when the pulse detection efficiency is equal to or more than the first threshold value, the seat is determined by the comparison determination means, and the pulse detection efficiency becomes equal to or less than the second threshold value which is smaller than the first threshold value. Is determined to be non-seated.

[0010]

Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a seating detection device according to one embodiment of the present invention. In the figure, reference numeral 11 denotes a transmission pulse signal 2 having a predetermined period and width as a signal for detecting seating.
1 is a pulse generator, 1 is a modulator that modulates the transmission pulse signal 21 to a predetermined frequency, for example, a frequency such as 38 kHz, and 2 is an LED 3 that outputs infrared rays based on the pulse signal modulated by the modulator 1. LED driving unit 4 for driving, a light receiving sensor for receiving and detecting a part of infrared light reflected from the user's body among infrared light output from LED 3, an amplifying unit for amplifying a detection output from light receiving sensor 4, 6 Is a band-pass filter that passes only signals near the modulation frequency in the modulation unit 1, and 7 is a waveform shaping unit that shapes and outputs the output from the filter 6 as a detection pulse signal 23.

Reference numeral 12 denotes a counting period generator for outputting a reset signal 31 serving as a reference for counting transmission / reception pulses, and 13 denotes a transmission pulse signal 21 from the pulse generator 11.
The transmission pulse counting unit 14 counts the detection pulse signal 23 from the waveform shaping unit 7 on the basis of the transmission pulse signal 21 from the pulse generation unit 11 and removes the detection pulse signal 23 due to noise. , A pulse judging unit that outputs a signal as a regular received pulse signal 25,
Is a reception pulse counting unit that counts the reception pulse signal 25 from the pulse determination unit 14, and 16 is a transmission pulse counting unit 13
A comparison / determination unit that determines whether the vehicle is seated or not seated in accordance with the count output from the received pulse counting unit 15 and outputs a seating signal as a determination result, and outputs a determination end signal 36 indicating the end of the determination operation in the determination period. It is.

FIG. 2 is a timing chart showing signals of various parts in the block diagram of FIG. 1. Reference numeral 21 denotes a transmission pulse signal output from the pulse generation unit 11, and reference numeral 22 denotes a modulation pulse signal modulated by the modulation unit 1. , 23 are detection pulse signals output from the waveform shaping section 7, 24 are internal signals of the pulse determination section 14, and 25 is a regular reception pulse signal output from the pulse determination section 14.

Next, the operation of the present invention will be described with reference to FIGS. Now, a transmission pulse signal 21 having a predetermined pulse width of, for example, about several milliseconds is continuously output from the pulse generation unit 11. The transmission pulse signal 21 is modulated by the modulation unit 1 and then transmitted to the LED drive unit 2. The LED 3 which is inputted and outputs infrared rays based on this signal is driven. A part of the infrared light output from the LED 3 is reflected on the human body of the user, and a part of the infrared light is detected by the light receiving sensor 4, amplified by the amplifier 5, and then input to the band-pass filter 6. You.

Since the filter 6 allows only signals near the modulation (carrier) frequency in the modulation section 1 to pass therethrough, of the signals detected by the light receiving sensor 4, the modulation pulse modulated by the modulation section 1 is used. The signal 22 is passed and output, and signals having frequencies outside this band are attenuated and output as noise. The waveform shaping section 7 shapes the waveform of the output including some distortion from the filter 6 as a rectangular detection pulse signal 23, and outputs the rectangular detection pulse signal 23 to the pulse determination section 14.

Here, since the detected pulse signal 23 from the waveform shaping section 7 contains noise (shaded area in FIG. 2) which cannot be removed by the filter 6, the pulse determining section 14 It is determined based on the transmission pulse signal 21 from whether the received pulse is a legitimate reception pulse. That is, when the detection pulse signal 23 is normal, it must be detected in a period synchronized with the transmission pulse signal 21. Therefore, the timing between the detection pulse signal 23 and the transmission pulse signal 21 is compared. You.

In FIG. 2, reference numeral 24 denotes an internal signal of the pulse judging unit 14 which indicates the logical product of the transmission pulse signal 21 and the detection pulse signal 23 as an internal signal of the pulse judging unit 14. Since the signal 23a is not detected within the period synchronized with the transmission pulse signal 21, it does not appear in the internal signal 24 indicating the logical product and is not output as the regular reception pulse signal 25. Also,
As for the detection pulse signals 23b and 23c, in which a sudden noise occurs continuously or overlapping before and after the transmission pulse signal 21, the detection pulse signal 23 is detected in a period synchronized with the transmission pulse signal 21. Therefore, the output appears in the internal signal 24 and the normal reception pulse signal 2
5 is output.

As shown in the detection pulse signals 23d and 23e, if noise is generated in a period synchronized with the transmission pulse signal 21, an output appears in the internal signal 24 indicating a logical product. May be erroneously detected. In such a case, by checking whether or not the width of the output pulse of the internal signal 24 is within an allowable range based on the width of the transmission pulse signal 21, the pulse is determined based on the normal transmission pulse signal 21. Can be determined.

As a result, the detection pulse signals 23d, 23
e, both of which occur within the period synchronized with the transmission pulse signal 21, but the overlap is part of the synchronization period, and the pulses 24 d, 24 d,
Since the width of 24 e is shorter than the width of the transmission pulse signal 21, it is determined that the noise is noise.
5 is not output, and more accurate pulse determination can be performed.

It should be noted that the pulse determination processing of these detection pulse signals 23, that is, the pulse generation timing is a period synchronized with the transmission pulse signal 21, and the pulse width is within an allowable range based on the width of the transmission pulse signal 21. As a method of determining that there is, the rising edge and the falling edge of the detection pulse signal 23 are compared with those of the transmission pulse signal 21 to check whether or not they are within a predetermined allowable range before and after the edge. The determination may be made. For example, the allowable range of the rising edge is earlier than that of the transmission pulse signal 21 and the allowable range of the falling edge is later than that of the transmission pulse signal 21.
It is possible to inspect the generation synchronization with the transmission pulse signal 21 and the pulse width at the same time, and the determination process in the pulse determination unit 14 is further speeded up.

Next, the seating / non-seat determination operation will be described with reference to FIG. FIG. 3 is a timing chart showing the sitting / non-seat determining operation.
Is a transmission pulse signal from the pulse generation unit 11, 25 is a normal reception pulse signal from the pulse determination unit 14, 31 is a reset signal from the counting period generation unit 12, 32 and 33 are the transmission pulse counting unit 13 and the reception pulse, respectively. Counting unit 15
Counter output signal indicating the count output from
Is a comparison / determination unit 1 indicating the difference between the counter output signals 32 and 33
Reference numeral 6 denotes an internal signal, and reference numeral 35 denotes a seating signal output from the comparison / determination unit 16 as a seating / non-seating determination result.

Here, the principle of the method for judging seating / non-seating in the present invention will be described. When the user is seated, the infrared light output from the LED 3 based on the transmission pulse signal 21 reflects on the user's body and is detected by the light receiving sensor 4 with a high probability. In such a case, it is detected with a low probability. Therefore, the number of transmitted pulses and the number of received pulses are counted in a predetermined pulse counting period t, and these are compared based on a predetermined reference, that is, a pulse detection efficiency which is a ratio of the number of transmitted / received pulses. Thus, it is possible to determine whether the seat is seated or not.

Now, the number of pulses transmitted in the period t is N
_s , the number of received pulses is N _r (N _s , N _r are positive integers), and the pulse detection efficiency, which is a condition for determining seating / specific sitting, is R
When the determination condition in period t end is seated: N _r / N _s ≧ _R unseated: it can be represented as N _r / N _{s <R.}

Accordingly, if the total number of pulses transmitted fixedly within the period t is N (N is a positive integer), the number of received pulses N with respect to the total number of pulses N even during the period t _When the ratio _Nr / N of _r increases and becomes equal to or higher than the pulse detection efficiency R, which is a criterion for determining whether a person is seated or not, at the end of the period t, even if pulses cannot be received over the remaining period. Since it is determined that the pulse detection efficiency at R is equal to or higher than R, it is possible to determine that the user is seated at this time. Therefore, the seating determination condition in the middle of the period t is _{seated: N r / N ≧ R ∴} N r ≧ N · R ‥‥ (1) become.

Conversely, even during the period t, the number of pulses N _s -N _r that have been transmitted but not received.
Percentage of total number N of pulses (N _s -N _r) / N is increased, i.e. the ratio of the number of pulses may be received 1-(N _s -
When _Nr ) / N decreases and falls below the pulse detection efficiency R, which is a criterion for determining whether a person is seated or not, the pulse detection efficiency at the end of the period t even if the pulse can be received over the entire remaining period. Is determined to be less than R, it is possible to determine that the vehicle is not seated at this time. Therefore, the non-seating determination condition in the middle of the period t is as follows: non-seated: 1− (N _s −N _r ) / N <R∴N _s −N _r > N · (1−R)） (2) .

In FIG. 1, the counting period generating section 12 supplies a reset signal 31 indicating a predetermined number of periods of the transmission pulse signal 21 as a signal for defining a pulse counting period t to each of the pulse counting sections 13 and 15. Always output. Thus, the transmission pulse counting unit 13 counts the transmission pulse signal 21 output from the pulse generation unit 11 every pulse counting period t, for example, every several hundred ms, and outputs the counter output signal 32. The pulse counting unit 15 also
The normal reception pulse signal 25 output from the pulse determination unit 14 is counted every pulse counting period t, and the counter output signal 33 is output.

Now, when the number N of pulses that can be transmitted during the pulse counting period t is 10 and the pulse detection efficiency R is 50%, the conditions of the above equations (1) and (2) are as follows: Seating: N _r ≧ 10 · 0.5 = 5 Non-seated: N _s −N _r > 10 · (1−0.5) = 5 At time T ₁₁ in FIG. 3, transmission pulse counting section 1
3 and the reception pulse counting unit 15 are reset in their internal counter values by the reset signal 31 from the counting period generation unit 12, respectively, and thereafter count the transmission pulse signal 21 and the reception pulse signal 25, respectively.

The comparing / determining section 16 includes a transmission pulse counting section 13
And the counter output signal 3 from the reception pulse counting unit 15
2, 33 are constantly checked, and the received pulse signal 25
There Since counter output signal 33 of the receiving side at a time T ₁₂ of what is discontinuous becomes "5" or more, it is determined that the seated outputs the seating signal 35 to that effect. The reset signal 3 from the counting period generating section 12 at time T ₁₃
After the internal counter value is reset by the 1, each transmission pulse counting unit 13 and the received pulse counting unit 15 starts counting, the comparison determination unit 16 determines at time T ₁₄ described above and the seating Similarly, in this case Since the seating signal 35 has already indicated the seating, the seating signal 35 is maintained and output.

[0028] In yet a new counting period from the time T _15, because that is already a non-sitting state, the number of transmission pulses received pulse signal 25 at the reception pulse counting unit 15 is inspected in the comparison determination unit 16 are not counted difference or the internal signal 34 is increased with the N _s and the received pulse number N _r, which is to become exceed "5" at time T _16, is output seating signal 35 indicating the unseated from the comparison determination unit 16 Will be.

Therefore, instead of simply outputting infrared rays continuously and detecting the amount of light in an analog manner as in the prior art,
Infrared light is transmitted as a pulse having a predetermined period and width, and the pulse is detected only during a period synchronized with the transmission timing. It is possible to remove noises having different periods from the noise. In addition, instead of determining whether the detection signal is continuous for a predetermined time or more as in the related art, it is not determined whether the vehicle is sitting or not seated. Since the determination is made, even if the pulse cannot be received continuously, it is possible to make the determination within the measurement period, and the time required for determination of sitting / non-seat is reduced.

Next, as another embodiment of the present invention, a judging operation in the case where the hysteresis characteristic is provided will be described with reference to FIG. FIG. 4 is a timing chart in the case where different pulse detection efficiencies are set as the determination criteria for sitting and non-seating, and the determination operation is provided with a hysteresis characteristic. The same signals as those described above (FIG. 3) have the same reference numerals. Is attached. FIG. 3 shows a case where the same pulse detection efficiency R is used for both the sitting and non-seating determination criteria.
FIG. 4 shows a case where the pulse detection efficiency for detecting the seating is R _on and the pulse detecting efficiency for the non-seating detection is R _off , each having different criteria.

FIGS. 5A and 5B are explanatory diagrams showing hysteresis characteristics in the judgment operation. FIG. 5A shows the relationship between the distance L between the LED 3 (light receiving sensor 4) and the human body and the pulse detection efficiency R, and FIG. 3 shows the relationship between detection efficiency R and determination. In general, when the distance L is small to some extent, the pulse detection efficiency R tends to decrease as the distance L increases, and as shown in FIG. Is determined, and Roff is determined as the pulse detection efficiency at the distance Loff determined to be non-seated. Further, as shown in FIG. 5 (b), when the pulse detection efficiency R once becomes Ron or more, it is not determined that the vehicle is not seated until the pulse detection efficiency R becomes less than Roff. Until Ron or more, seating is not determined.

In FIG. 4, the number N of pulses that can be transmitted during the pulse counting period t is 10, and the sitting pulse detection efficiency R _on
Is 60% and the non-seating pulse detection efficiency R _off is 20%, the conditions of the above-described equations (1) and (2) are as follows: Seating: N _r ≧ 10 · 0.6 = 6 Non-seating: N _s − the _{N r ≧ 10 · (1-0.2)} = 8.

The comparison determination unit 16, the counter output signal 33 from the received pulse counter 15 at time T ₂₁ outputs a seating signal 35 indicating the seating detects that it is now "6".
Further, the counting period from the time T _22, shows the case where the number of received pulse infrared reflection direction due user changes posture due is changed is temporarily reduced, the number of received pulses in this case _Nr and the difference _Ns−
Both N _r not a determining condition is satisfied, it is assumed that the output of the previous period is maintained as the seating signal 35. Has a non-seating state by further counting period from the time T _23, it is detected that at time T ₂₄ the difference N _s -N _r number reception pulse is "8" seating signal 35 indicating the unseated Is output.

Accordingly, by setting different pulse detection efficiencies as a criterion for determining whether a person is seated or not, if the received pulse signal 25 cannot be detected stably, for example, if the user changes his or her body position, If a small number of received pulse signals 25 are not detected, for example, even if noise is detected due to disturbance light or erroneous detection due to cleaning of an automatic sanitary washing device, stable sitting / non-seat determination can be performed. Becomes

In the above description, the case where the pulse counting period t is set to a constant period has been described.
A new pulse counting period t may be started in response to the end of the non-seated determination. FIG. 6 is a timing chart in a case where a new pulse counting period t is started in accordance with the end of the determination of sitting / non-seat, and the same reference numerals are used for the same signals as those described above (FIGS. 3 and 4). In particular, the received pulse signal 25 has the same pattern as in FIG.

The comparison determination unit 16 detects that the count output signal 33 from the received pulse counting unit 15 at time T ₃₁ becomes "6" is a seating criterion, outputs a seating signal 35 indicating the seating And counting period generating section 1
2, a determination end signal 36 indicating the end of the determination operation in the current counting period is transmitted, and the counting period generating unit 12
In response to the determination end signal 36, a reset signal 31 for instructing the start of a new pulse counting period is output, whereby the internal counters of the pulse counting units 13 and 15 are reset, and the counting of new pulses is started. . Therefore,
It is possible to shift to the next sitting / non-seating judgment at the same time as the judgment is completed, and the delay time from the actual sitting / non-seating operation to the judgment is shortened as compared with the case where the pulse counting period is fixed (for example, FIG. 4). Therefore, it is possible to further reduce problems caused by various control delays of the automatic sanitary washing device due to the determination delay.

In the above description, the modulating unit 1, the pulse generating unit 11, the counting period generating unit 12, the transmitting pulse counting unit 13, the pulse judging unit 14, the receiving pulse counting unit 15, and the comparing and judging unit 16 The case where the components are constituted by independent circuit units has been described. However, even when all or a part of these units are constituted by an arithmetic processing unit (CPU), the same operation and effect as described above can be obtained.

[0038]

As described above, according to the present invention, there is provided a transmitting means for outputting a pulsed infrared ray based on a transmission pulse signal having a predetermined period and width, and a reflected light reflected from a user's body among infrared rays. Receiving means for detecting a part of the signal as a received pulse signal, and counting period generating means for outputting a reset signal indicating a pulse counting period every predetermined time,
A transmission pulse counting unit that counts and outputs the number of transmission pulses output from the transmission unit and initializes the number of transmission pulses based on the reset signal; and counts and outputs the number of reception pulses output from the reception unit and receives based on the reset signal. A receiving pulse counting unit for initializing the number of pulses, wherein the comparing and judging unit judges sitting / non-seating based on pulse detection efficiency indicating a ratio of the number of received pulses to the number of transmitted pulses in the pulse counting period. It was made.

Therefore, as in the prior art, the infrared ray is simply output continuously, the amount of the infrared ray is detected in an analog manner, and it is determined whether or not the detection signal is continuous for a predetermined time or longer to determine whether the seat is seated or not. Instead of transmitting the infrared rays as a pulse having a predetermined period and width and receiving the same, the pulse is continuously determined by determining based on the pulse detection efficiency indicating the number of received pulses with respect to the number of transmitted pulses in a predetermined period. Is not received, it is possible to determine within the measurement period,
The time required for determination of non-seating is reduced, and stable determination can be performed.

Further, the receiving means is provided with a pulse determining means for discriminating and removing noise, and among the detected pulse signals, those output during a period synchronized with the transmission pulse signal are output as regular reception pulse signals. As a result, it is possible to remove spontaneous noise due to disturbance light and noise with a different period from lighting equipment with an inverter circuit, etc., and realize more accurate judgment of sitting and non-seating. It becomes possible. Further, when the pulse detection efficiency is equal to or greater than the first threshold, the seat is determined by the comparison determination means, and the pulse detection efficiency is equal to or less than the second threshold smaller than the first threshold. When a pulse cannot be detected stably, for example, when the user changes his or her body position, or when a small number of pulses that are not based on seating are detected, Even if the detection is erroneous due to noise caused by the noise or the cleaning of the sanitary washing device, it is possible to perform stable sitting / non-seat determination.

[Brief description of the drawings]

FIG. 1 is a block diagram of a seating detection device according to one embodiment of the present invention.

FIG. 2 is a timing chart showing a pulse determination operation.

FIG. 3 is a timing chart showing a seat determination operation.

FIG. 4 is a timing chart showing a seat determination operation according to another embodiment of the present invention.

FIG. 5 is an explanatory diagram showing a hysteresis characteristic of a determination operation.

FIG. 6 is a timing chart showing a seat determination operation according to another embodiment of the present invention.

FIG. 7 is an external view showing a general sanitary washing device.

FIG. 8 is an explanatory view showing a sensor unit of a general seating detection device.

FIG. 9 is a timing chart showing a seat determination operation performed by a conventional seat detection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Modulation part 2 LED drive part 3 LED 4 Light-receiving sensor 5 Amplification part 6 Filter 7 Waveform shaping part 11 Pulse generation part 12 Count period generation part 13 Transmission pulse counting part 14 Pulse judgment part 15 Reception pulse counting part 16 Comparison judgment part 21 Transmission Pulse signal 22 Modulation pulse signal 23 Detection pulse signal 25 Receive pulse signal 31 Reset signal 32, 33 Counter output signal 35 Seating signal 36 Judgment end signal

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-58-124978 (JP, A) JP-A-3-181878 (JP, A) JP-A-61-75280 (JP, A) JP-A-3- 172789 (JP, A) JP-A-61-135222 (JP, A) JP-A-59-99386 (JP, A) JP-A-7-65260 (JP, A) JP-A-61-124883 (JP, A) Actual Opening Sho 64-87 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01S 7/48-7/51 G01S 17/00-17/95

Claims (3)

(57) [Claims] 1. A transmitting means for outputting a pulsed infrared ray based on a transmission pulse signal having a predetermined cycle and width, and a reception pulse signal which detects a part of the infrared light reflected by a user's body and detects a part of the reflected light. Receiving means for outputting a reset signal indicating a pulse counting period at predetermined time intervals; counting and outputting the number of transmission pulses output from the transmitting means; and transmitting the pulse based on the reset signal. Transmitting pulse counting means for initializing the number of pulses; receiving pulse counting means for counting and outputting the number of receiving pulses output from the receiving means; and initializing the number of receiving pulses based on the reset signal; and A pulse detection efficiency indicating a ratio of the number of reception pulses to the number of transmission pulses within a period, and
Ratio between two thresholds indicating the sitting and non-seating judgment conditions
By compare, seating detection apparatus characterized by comprising a comparing determining means for determining seating-unseated. 2. The seating detection device according to claim 1, wherein the receiving unit outputs the detected pulse signal during a period synchronized with the transmission pulse signal .
The width is within the allowable range of the transmission pulse signal width.
Seating detection apparatus characterized by having a pulse judging means for outputting the as received pulse signal of the normal. 3. The seating detection device according to claim 1, wherein the comparing and judging means judges that the seating is performed when the pulse detection efficiency is equal to or higher than a first threshold value, and the pulse detection efficiency is equal to the first threshold value. A seating detection device characterized in that it is determined that the vehicle is not seated when the value becomes equal to or less than a second threshold value smaller than the threshold value.