Patent Publication Number: US-2023157641-A1

Title: Absolute isolated light path structure, and seat ring and toilet deat using asbolute isolated light path structure

Description:
TECHNICAL FIELD 
     The present disclosure relates to the field of toilet seat technologies, and specifically to an absolute isolated light path structure, and a seat ring and a toilet seat having the same. 
     BACKGROUND 
     A closestool, also known as a toilet, is a necessary fixture in people&#39;s daily life, and smart toilet seats are popular because of its medical and health effects. At present, a smart toilet seat is able to collect human biometric characteristics, such as electrocardiographic (ECG) signals, to achieve the purpose of monitoring health status of human bodies. 
     Photo-plethysmography (PPG) is a technique for acquiring plethysmogram of organs optically, which is usually implemented by irradiating the skin with a pulse oximeter and measuring the amount of change in light absorption. The PPG signal may be adopted to calculate the body&#39;s oxyhemoglobin saturation, heart rate, blood pressure and other physiological indicators. The PPG signal is generally acquired via optical signals with two wavelengths of 940 nm and 650 nm, and by ways of transmission absorption (e.g., at the fingertips, earlobes) or reflection (e.g., on the forehead). 
     According to the existing optical technology for acquiring the PPG signals by reflection, the light-emitting and light-receiving portions may share the same piece of light-transmitting material for implementing the light-guiding and waterproofing processing no matter in discrete devices or an integrated sensor, as shown in  FIG.  1   . Both the light-emitting light source and the light-receiving photocell contact the human body across the same light-transmitting medium, and no light-transmitting material enables the light energy transmission of 100%, which may inevitably cause total reflection, refraction or other phenomena. Thus, the light-receiving portion may inevitably suffers from partial direct radiation of the light source signal, which appears as spurs parasitic on the signal waveform when the PPG signal is weak and thereby deteriorates the signal quality. 
     SUMMARY 
     In view of this, it is necessary to provide an absolute isolated light path structure to avoid interference from the light emitting portion to the light receiving portion, and also a seat ring and toilet seat having the absolute isolated light path structure. 
     Provided is an absolute isolated light path structure, which includes: a light blocking plate; and a light emitting device and a light receiving device separated by the light blocking plate, wherein the light blocking plate is configured to block light propagation between the light emitting device and the light receiving device. 
     Furthermore, the light emitting device includes a light emitter and an emitter light-transmitting sheet disposed above the light emitter; the light receiving device includes a light receiver and a receiver light-transmitting sheet disposed above the light receiver; and the light blocking plate is disposed between the light emitter and the light receiver and extends between the emitter light-transmitting sheet and the receiver light-transmitting sheet. 
     Furthermore, the emitter light-transmitting sheet and the receiver light-transmitting sheet have respective upper surfaces flush with an upper surface of the light blocking plate. 
     In addition, provided is a seat ring having an absolute isolated light path structure, which includes: a body signal extraction unit, wherein the body signal extraction unit is fitted with the absolute isolated light path structure described above and configured to extract a PPG signal from a human body. 
     Furthermore, the seat ring further includes a seat surface and a bottom surface opposite to the seat surface, wherein the seat surface is provided with a mounting hole penetrating therethrough; and 
     the light emitting device and the light receiving device are mounted in, with a gap around the light emitting device and the light receiving device in the mounting hole being filled with a light blocking material that forms the light blocking plate. 
     Furthermore, the mounting hole is entirely filled with the light blocking material provided with two through holes; and 
     the two through holes include a light emitter mounting hole and a light receiver mounting hole configured to mount the light emitting device and the light receiving device, respectively. 
     Furthermore, the light emitter mounting hole and the light receiver mounting hole are provided in parallel. 
     Furthermore, the emitter light-transmitting sheet, the receiver light-transmitting sheet, and the light blocking plate have respective upper surfaces flush with the seat surface of the seat ring. 
     In addition, provided is a toilet seat, which includes the absolute isolated light path structure described above and a weak electrical signal acquisition circuit for acquiring an ECG signal of a human body. 
     The weak electrical signal acquisition circuit includes two signal acquisition units that include two signal receiving electrode sheets and two operational amplifiers, wherein the two operational amplifiers form a differential circuit; and 
     the differential circuit further includes a first feedback resistor R 3 , a second feedback resistor R 3 ′ and a negative feedback circuit provided between the first feedback resistor R 3  and the second feedback resistor R 3 ′. 
     Furthermore, the two signal receiving electrode sheets are active electrode sheets, and are configured to receive common mode signals and differential mode signals; 
     the negative feedback circuit is formed by a single resistor or a network assembly consisting of a plurality of electronic components and having a frequency characteristic; or, 
     the negative feedback circuit includes a network assembly having a frequency characteristic of all pass, low pass, high pass, band pass or band resistance. 
     The present disclosure has following advantageous technical effects. 
     1. According to the present disclosure, the light blocking plate is provided between the light emitting device and the light receiving device, such that the light emitting device and the light receiving device can emit and receive light independently, thereby preventing the light emitted by the light emitting device from interfering with the light receiving device. 
     2. The light path of the light emitting device is completely isolated from that of the light receiving device, such that the light emitted by the light emitting device is prevented from interfering with the light receiving device before being reflected by the human body, thereby improving the quality of the PPG signal acquired from thick fatty parts. 
     3. By taking the two signal acquisition units as pre-input electrodes of an amplification circuit and adopting the in-phase differential input mode, the amplitude ratio of differential mode signals to common mode signals as sent to a post-operational amplifier is increased, and the purpose of improving the signal-to-noise ratio of the input signal can be achieved, such that the toilet seat can extract ECG signals from the human body effectively. 
     4. When people use the toilet, the toilet seat fitted with the weak signal acquisition circuit can collect ECG signals from legs, and can still effectively extract ECG signals from human body even in dry winters. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic diagram of a light path structure of a toilet seat in the prior art; 
         FIG.  2    is a schematic diagram of a light path structure of an absolute isolated light path structure according to an embodiment of the present disclosure; 
         FIG.  3    is an enlarged schematic structural diagram of a part of a mounting hole of a body signal extraction unit of a seat ring having an absolute isolated optical path structure according to an embodiment of the present disclosure; 
         FIG.  4    is a schematic structural diagram of the seat ring having an absolute isolated optical path structure according to an embodiment of the present disclosure; and 
         FIG.  5    is a schematic structural diagram of a weak signal acquisition circuit of the toilet seat according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure will be further illustrated in detail in combination with the specific embodiments and accompanying drawings. 
     EXAMPLE 1 
     Referring to  FIG.  2   , it illustrates an absolute isolated light path structure, which includes a light blocking plate  123 , and a light emitting device  121  and a light receiving device  122  separated by the light blocking plate  123 . The light blocking plate  123  is configured to block light propagation between the light emitting device  121  and the light receiving device  122 . 
     Furthermore, the light emitting device  121  includes a light emitter  1211  and an emitter light-transmitting sheet  1212  disposed above the light emitter  1211 ; the light receiving device  122  includes a light receiver  1221  and a receiver light-transmitting sheet  1222  disposed above the light receiver  1221 ; and the light blocking plate  123  is disposed between the light emitter  1211  and the light receiver  1221  and extends between the emitter light-transmitting sheet  1212  and the receiver light-transmitting sheet  1222 . 
     Furthermore, the emitter light-transmitting sheet  1212  and the receiver light-transmitting sheet  1222  have respective upper surfaces flush with an upper surface of the light blocking plate  123 . 
     Specifically, the light blocking plate  123  completely isolates the light transmitting device  121  from the light receiving device  122 , such that the light emitted from the light emitter  1211  cannot transmit to the light receiver  1221  via the shared light guiding plate, thereby reducing the light interference signals as received by the light receiver  1221 . 
     Preferably, the light blocking material is made of a metallic material or other light-opaque material. 
     In this embodiment, the light blocking plate  123  completely isolates the light transmitting device  121  from the light receiving device  122 , thereby preventing the light emitted by the light emitting device  121  from interfering the light receiving device  122 . 
     EXAMPLE 2 
     Referring to  FIG.  4   , the present disclosure further discloses a seat ring  10  having an absolute isolated light path structure. As shown in  FIG.  4   , the seat ring  10  includes a body signal extraction unit, and the body signal extraction unit is fitted with the absolute isolated light path structure described above and configured to extract a PPG signal from a human body. 
     Furthermore, referring to  FIG.  3   , the seat ring  10  has a seat surface and a bottom surface opposite to the seat surface, and the seat surface is provided with a mounting hole  12  penetrating therethrough. The light emitting device  121  and the light receiving device  122  are mounted in the mounting hole  12 , with a gap around the light emitting device  121  and the light receiving device  122  in the mounting hole  12  being filled with a light blocking material that forms the light blocking plate  123 . The mounting hole  12  is entirely filled with the light blocking material provided with two through holes. The two through holes include a mounting hole for the light emitter  1211  and a mounting hole for the light receiver  1221 , which are configured to mount the light emitting device  121  and the light receiving device  122  respectively. In addition, the mounting hole for the light emitter  1211  and the mounting hole for the light receiver  1221  are provided in parallel. 
     Furthermore, the emitter light-transmitting sheet  1212 , the receiver light-transmitting sheet  1222 , and the light blocking plate  123  have respective upper surfaces flush with the seat surface of the seat ring  10 . 
     Specifically, the seat ring  10  having the absolute isolated light path structure according to this embodiment may be mounted either on a normal toilet seat without heating and flushing functions or on a smart toilet seat with heating and flushing functions and functions of detecting human physiological parameters (e.g. body fat parameters, weight parameters, ECG signals, etc.). 
     According to this embodiment, in the toilet seat fitted with the absolute isolated light path structure, the light path of the light emitting device  121  is completely isolated from that of the light receiving device  122 , such that the light emitted by the light emitting device  121  is prevented from interfering the light receiving device  122  before being reflected by the human body, thereby improving the quality of the PPG signals as acquired from thick fatty parts. 
     EXAMPLE 3 
     The present disclosure further discloses a toilet seat that includes the absolute isolated light path structure described above and a weak electrical signal acquisition circuit for acquiring an ECG signal of a human body. Referring to  FIG.  5   , the weak electrical signal acquisition circuit includes two signal acquisition units that include two signal receiving electrode sheets  111  and two operational amplifiers. The two operational amplifiers form a differential circuit, and the differential circuit further includes a first feedback resistor R 3 , a second feedback resistor R 3 ′ and a negative feedback circuit provided between the first feedback resistor R 3  and the second feedback resistor R 3 ′. 
     Furthermore, the two signal receiving electrode sheets  111  are active electrode sheets, and are configured to receive common mode signals and differential mode signals. The negative feedback circuit is formed by a single resistor or a network assembly consisting of a plurality of electronic components and having a frequency characteristic; or, the negative feedback circuit includes a network assembly having a frequency characteristic of all pass, low pass, high pass, band pass or band resistance. 
     Specifically, the toilet seat according to this embodiment may include both an ordinary toilet seat without heating and flushing functions and a smart toilet seat with the heating and flushing functions. 
     Specifically, when people use the toilet, the toilet seat fitted with the weak signal acquisition circuit can collect ECG signals from legs, and can still effectively extract ECG signals of human body even in dry winters. 
     According to this embodiment, the weak signal acquisition circuit can reduce the interference of external electrical signals to the signal acquisition unit and improves the accuracy of the system in acquiring ECG signals of the human body. 
     It shall be noted that the above description is only the preferred embodiments of the present disclosure, and is not intended to limit the present disclosure. For those skilled in the art, various modifications and changes can be made to the present disclosure. Any modification, equivalent replacement, improvement, and the like as made according to the spirit and principle of the present disclosure shall be regarded as within the protection scope of the present disclosure.