Detection sensor and detection device including the detection sensor

Abstract

A detection sensor and a detection device including the detection sensor. The present invention provides a detection sensor that prevents dirt, dust and / or water from entering. The detection sensor S includes a vibrating membrane (100) composed of a piezoelectric film, a housing (200) that accommodates the vibrating membrane (100), and a circuit board (300). The vibrating membrane (100) is configured to be irradiated with infrared rays and thereby generate a first electrical signal through a pyroelectric effect, and is configured to be vibrated by sound waves and thereby generate a second electrical signal through a piezoelectric effect. The circuit board (300) is fixed to the housing (200) and is arranged on the Z' direction side relative to the vibrating membrane (100). The housing (200) includes a transmission portion (220) configured to transmit at least infrared rays. The transmission portion (220) is arranged on the Z direction side relative to the vibrating membrane (100) to face the vibrating membrane. The Z-Z' direction is the thickness direction of the vibrating membrane. The circuit board has a sound hole to input sound waves through the sound hole.

Description

Technical Field

[0001] The invention relates to a detection sensor and a detection device comprising the detection sensor. Background Art

[0002] A conventional detection sensor is described in the unexamined utility model application No. S56-48189 disclosed in Japan. The detection sensor includes a housing having an opening, a pyroelectric film, a piezoelectric film, a first field effect transistor, and a second field effect transistor. The pyroelectric film is arranged in the housing so as to face the opening. The piezoelectric film is arranged at a predetermined interval from the pyroelectric film, and the space between them is airtight. The piezoelectric film has a face facing the pyroelectric film and a light reflecting electrode arranged on the face-to-face relationship. When the pyroelectric film is subjected to infrared rays incident through the opening and infrared rays passing through the pyroelectric film and then reflected by the electrodes of the piezoelectric film, a detection signal is generated and input into the first field effect transistor. The first field effect transistor is configured to perform impedance conversion on the input detection signal and output the converted detection signal as an output signal. The sound wave incident through the opening vibrates the pyroelectric film, and the vibration is transmitted to the piezoelectric film and vibrates the piezoelectric film to generate a detection signal to be input into the second field effect transistor. The second field effect transistor is configured to perform impedance conversion on the input detection signal and output the converted detection signal as an output signal. Therefore, conventional detection sensors are capable of detecting both infrared rays and sound waves. Summary of the invention

[0003] Technical issues

[0004] The conventional detection sensor described above receives infrared rays and sound waves through a common opening, which is wide enough to capture infrared rays. Therefore, the opening easily allows dirt, dust and / or water to enter the conventional detection sensor through it.

[0005] The present invention provides a detection sensor which can prevent dirt, dust and / or water from entering. The present invention also provides a detection device comprising the detection sensor.

[0006] Technical Solution

[0007] A detection sensor according to one aspect of the present invention includes a vibrating membrane composed of a piezoelectric film, a housing for accommodating the vibrating membrane, and a circuit board. The vibrating membrane is configured to be irradiated with infrared rays and thereby generate a first electrical signal through a thermoelectric effect, and is configured to be vibrated by sound waves and thereby generate a second electrical signal through a piezoelectric effect. The housing includes a transmission portion. The transmission portion is configured to transmit at least infrared rays and is arranged on one side of a first direction relative to the vibrating membrane to face the vibrating membrane. The first direction is a thickness direction of the vibrating membrane. The circuit board is fixed to the housing and is arranged on the other side of the first direction relative to the vibrating membrane. The circuit board has a sound hole to input sound waves through the sound hole.

[0008] The transmission part may be provided not in the housing but in the circuit board and on the other side of the first direction relative to the vibratable membrane. In this case, the sound hole may be provided not in the circuit board but in the top plate of the housing.

[0009] The detection sensor of any of the above aspects prevents entry of dirt, dust and / or water for the following reasons. The detection sensor is configured so that the vibrating membrane is irradiated by infrared light passing through the transmission portion. Therefore, the detection sensor does not have an opening for projecting infrared light into the detection sensor. The circuit board or the housing is provided with a sound hole, but the size of the hole is very small. Therefore, it is impossible for dirt, dust and / or water to enter the detection sensor through the sound hole.

[0010] In a cross section along a second direction substantially orthogonal to the first direction, a size of the sound hole may be smaller than a size of the transmission portion.

[0011] The transmission section may be constituted by an optical filter configured to transmit infrared rays in a predetermined wavelength band.

[0012] The vibrating membrane may include a membrane body and a first electrode and a second electrode. The membrane body may have a first surface on one side of a first direction and a second surface on the other side of the first direction. The first electrode may be disposed on the first surface of the membrane body. The second electrode may be disposed on the second surface of the membrane body.

[0013] The detection sensor of any of the above aspects may further include a field effect transistor. The field effect transistor may be configured to perform impedance conversion on the first electrical signal and / or the second electrical signal received from the vibratable membrane and output the converted first electrical signal and / or the converted second electrical signal as an output signal.

[0014] The detection device according to one aspect of the present invention may include a detection sensor, a low-pass filter and a high-pass filter according to one of the above aspects. The low-pass filter may be configured to receive an output signal from a field effect transistor, so as to pass a signal in a frequency band obtained by impedance conversion of a first electrical signal in the received output signal, and attenuate a signal in a frequency band higher than the frequency band of a signal that can pass through the low-pass filter. The high-pass filter may be configured to pass a signal in a frequency band higher than the frequency band of a signal that can pass through the low-pass filter in the output signal, and attenuate a signal in a frequency band lower than the frequency band of a signal that can pass through the high-pass filter.

[0015] The detection device may further include a controller. The controller may be configured to receive the signal that has passed through the low pass filter and the signal that has passed through the high pass filter, and determine whether the controller receives the signal only from the low pass filter.

[0016] The controller may be further configured such that if the controller determines that the controller receives a signal only from a low pass filter, the controller performs signal processing on an output signal from the field effect transistor, or alternatively, performs signal processing on a signal that has passed through the low pass filter and a signal that has passed through a high pass filter. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic cross-sectional view of a detection sensor according to a first embodiment of the present invention.

[0018] Figure 2 is a block diagram of a detection device according to a first embodiment of the present invention.

[0019] Figure 3 It is a schematic cross-sectional view of a modified example of the detection sensor.

[0020] Reference Symbols List

[0021] D: Detection device

[0022] S, S': Detection sensor

[0023] 100: Vibrating membrane

[0024] 110: membrane body; 120: first electrode; 130: second electrode

[0025] 200,200': Shell

[0026] 210: housing body; 211: top plate; 211a: opening; 212: tubular portion; 212a: end portion; 220: transmission portion

[0027] 230: Sound hole

[0028] 300: Circuit board

[0029] 310: Sound hole

[0030] 320: Transmission

[0031] 400: Field Effect Transistor (FET)

[0032] 500: Conductive ring

[0033] 600: Gate ring

[0034] 700: Retainer

[0035] 810: Low pass filter

[0036] 820: High pass filter

[0037] 830: Controller DETAILED DESCRIPTION

[0038] A first embodiment of the present invention and its design modifications will now be described. It should be noted that the embodiments and their modified compositions to be described can be combined in any possible manner. The materials, shapes, sizes, quantities, arrangements, etc. of the various aspects of the embodiments and their modified compositions will be discussed below only as examples and can be modified as long as they achieve similar functions.

[0039] First embodiment

[0040] Described below are detection sensors S according to various embodiments, including the reference Figure 1 The first implementation method. Figure 1 A detection sensor S according to a first embodiment is shown. Figure 1 The Z-Z' direction (first direction) and the XX' direction (second direction) are shown. The Z-Z' direction includes the Z direction (one side of the first direction) and the Z' direction (the other side of the first direction). The XX' direction is substantially orthogonal to the Z-Z' direction and includes the X direction and the X' direction.

[0041] The detection sensor S includes a vibrating membrane 100. The vibrating membrane 100 is composed of a piezoelectric film exhibiting pyroelectricity. The vibrating membrane 100 includes a membrane body 110, a first electrode 120, and a second electrode 130. For example, the membrane body 110 can be a synthetic resin film having a size (thickness dimension) of about 0.015 mm to about 0.030 mm in the Z-Z' direction. The membrane body 110 has a first face on the Z direction side and a second face on the Z' direction side. The first electrode 120 is disposed on the first face of the membrane body 110. The second electrode 130 is disposed on the second face of the membrane body 110. The Z-Z' direction is the thickness direction of the vibrating membrane 100.

[0042] The vibratable membrane 100 is configured to be irradiated with infrared rays and thereby generate a first electrical signal through a pyroelectric effect. Specifically, when not irradiated with infrared rays, the vibratable membrane 100 is spontaneously polarized. When the vibratable membrane 100 is irradiated with infrared rays and the temperature of the vibratable membrane 100 changes, the spontaneous polarization of the vibratable membrane 100 changes accordingly to cause a voltage change of the vibratable membrane 100, that is, to generate a first electrical signal.

[0043] The vibratable membrane 100 is also configured to be vibrated by the sound wave and thereby generate a second electric signal by the piezoelectric effect. Specifically, the vibratable membrane 100 is configured to be deformed by vibration and thereby cause a change in voltage, ie, generate a second electric signal.

[0044] The detection sensor S also includes a housing 200. The housing 200 accommodates the vibrating membrane 100. The housing 200 includes a housing body 210 and a transmission portion 220. The housing body 210 includes a top plate 211 and a tubular portion 212. The top plate 211 is arranged on the Z direction side relative to the vibrating membrane 100. The top plate 211 has an opening 211a passing through the top plate 211 in the Z-Z' direction. The tubular portion 212 extends from the peripheral portion of the top plate 211 in the Z' direction. The tubular portion 212 has an end 212a on the Z' direction side. The end 212a can be bent roughly in an L shape or can extend in the Z-Z' direction.

[0045] The transmission part 220 is assembled in the opening 211a. Therefore, in the cross section along the XX' direction, the transmission part 220 has an outer shape substantially the same as the shape of the opening 211a, and has an outer size that is the same as or slightly larger than the size of the opening 211a. The transmission part 220 is arranged on the Z direction side relative to the vibrating membrane 100 to face the vibrating membrane 100. The transmission part 220 is configured to transmit at least infrared rays. For example, the transmission part 220 can be composed of an optical filter configured to transmit infrared rays of only a predetermined wavelength band (for example, 1.2μm to 1.4μm (1200nm to 1400nm)), an optical filter configured to transmit infrared rays of a wavelength band of 780nm to 1mm, or an optical filter configured to transmit infrared rays and light of one or more wavelength bands near the infrared band (for example, visible light of a wavelength band of about 400nm to 780nm and / or microwaves having a wavelength band from 1mm to 1m). The optical filter may be composed of an optical lens made of silicon, for example, but is not limited thereto. Instead of the optical filter, the transmission portion 220 may be composed of a transparent or translucent material (e.g., synthetic resin or glass) configured to transmit at least infrared rays. The infrared rays transmitted through the transmission portion 220 of any of the above aspects are projected onto the vibrating membrane 100.

[0046] The detection sensor S further includes a circuit board 300. The circuit board 300 is fixed to the housing 200. For example, the circuit board 300 may be fixed to the end portion 212a (see FIG. 21A ) of the tubular portion 212 of the housing 200 that is bent substantially in an L shape. Figure 1 ); the end portion 212a of the tubular portion 212 of the housing 200 extending in the Z-Z' direction may be securely received in an engagement hole (not shown) of the circuit board 300 and thereby fixed to the engagement hole of the circuit board 300; or the end portion 212a of the tubular portion 212 of the housing 200 extending in the Z-Z' direction may be bonded to the circuit board 300 with a conductive adhesive or the like (not shown) and thereby fixed to the circuit board 300. The circuit board 300 is disposed on the Z' direction side relative to the vibratable membrane 100 and is spaced apart from the vibratable membrane 100.

[0047] The circuit board 300 includes a sound hole 310. The sound hole 310 extends through the circuit board 300 in the Z-Z' direction. In the cross section along the XX' direction, the sound hole 310 has a shape that is the same as or different from the outer shape of the transmission portion 220. In the cross section along the XX' direction, the sound hole 310 may have a size that is smaller than the outer size of the transmission portion 220, but is not limited thereto. For example, the sound hole 310 may have a size (diameter) between 0.6 mm and 0.8 mm in the cross section along the XX' direction. The sound hole 310 may face the vibrating membrane 100, or there may be another member between the sound hole 310 and the vibrating membrane 100. The sound waves input through the sound hole 310 will cause the vibrating membrane 100 to vibrate. A waterproof plate and / or a dustproof plate (not shown) may be fixed to the circuit board 300 from the Z' direction side to close the sound hole 310 from the Z' direction side. These plates may be omitted.

[0048] The detection sensor S may further include a field effect transistor 400 (FET 400). The FET 400 is electrically connected to the vibrating membrane 100. The FET 400 may be mounted on the circuit board 300, or may be mounted on another circuit board (not shown) electrically connected to the circuit board 300. The FET 400 is configured to receive the first electrical signal and / or the second electrical signal from the vibrating membrane 100, and perform impedance conversion on the first electrical signal and / or the second electrical signal to output the converted first electrical signal and / or the converted second electrical signal as an output signal.

[0049] The detection sensor S may further include a conductive ring 500 and a tubular gate ring 600. The conductive ring 500 is interposed between the peripheral portion of the vibrating membrane 100 and the top plate 211 of the housing 200, and is in contact with the first electrode 120 of the vibrating membrane 100. In this case, the housing body 210 of the housing 200 is made of a conductive material. The gate ring 600 is conductive, interposed between the peripheral portion of the vibrating membrane 100 and the circuit board 300, and is in contact with the second electrode 130 of the vibrating membrane 100. The first electrode 120 of the vibrating membrane 100 is electrically connected to the FET 400 via the conductive ring 500, the housing body 210, and the circuit board 300, while the second electrode 130 of the vibrating membrane 100 is electrically connected to the FET 400 via the gate ring 600 and the circuit board 300. Therefore, the FET 400 is electrically connected to the vibrating membrane 100.

[0050] The detection sensor S may further include a tubular retainer 700. The retainer 700 is electrically insulated. The retainer 700 is disposed between the gate ring 600 and the tubular portion 212 of the housing body 210. Therefore, in a cross section along the XX' direction, the retainer 700 has an internal shape identical to an external shape of the gate ring 600, and has an internal dimension substantially identical to or slightly larger than an external dimension of the gate ring 600. In addition, in a cross section along the XX' direction, the retainer 700 has an external shape identical to an internal shape of the tubular portion 212 of the housing body 210, and has an external dimension substantially identical to or slightly smaller than an internal dimension of the tubular portion 212 of the housing body 210. The retainer 700 may or may not be in contact with a portion of the vibrating membrane 100 that is outside the portion of the vibrating membrane 100 that is in contact with the gate ring 600. In addition, the holder 700 may or may not be in contact with the circuit board 300 .

[0051] Described below is a detection device D according to a plurality of embodiments, including the reference Figure 2 The first implementation method. Figure 2 A detection device D according to a first embodiment is shown.

[0052] The detection device D may include a detection sensor S according to one of the above aspects, a low pass filter 810 , and a high pass filter 820 .

[0053] The low-pass filter 810 may be provided on a circuit board (not shown) electrically connected to the circuit board 300 or on the circuit board 300. The low-pass filter 810 is electrically connected to the FET 400 via the circuit board 300, and is configured to receive an output signal from the FET 400. The low-pass filter 810 is configured to pass signals in a frequency band (first frequency band) among the received output signals, and the signals in the first frequency band are obtained by impedance conversion of the first electrical signal. The low-pass filter 810 is also configured to attenuate signals in a frequency band higher than the first frequency band (whose frequency band signals can pass through the low-pass filter 810). Specifically, the signal obtained by impedance conversion of the first electrical signal falls within a frequency band between 0.35 Hz and 5.0 Hz, and therefore, the low-pass filter 810 is configured to pass signals in a frequency band of 5.0 Hz and lower among the received output signals, and attenuate signals in a frequency band higher than 5.0 Hz (excluding 5.0 Hz).

[0054] The high-pass filter 820 may be disposed on a circuit board (not shown) electrically connected to the circuit board 300 or on the circuit board 300. The high-pass filter 820 is electrically connected to the FET 400 via the circuit board 300 and is configured to receive an output signal from the FET 400. The high-pass filter 820 is configured to pass signals in a frequency band (second frequency band) higher than the first frequency band (whose frequency band signals can pass through the low-pass filter 810) in the received output signal. The high-pass filter 820 is also configured to attenuate signals in a frequency band lower than the second frequency band (whose frequency band signals can pass through the high-pass filter 820). Specifically, the high-pass filter 820 is configured to pass signals in a frequency band higher than 10.0 Hz (excluding 10.0 Hz) and attenuate signals in a frequency band of 10.0 Hz and lower.

[0055] The detection device D may further include a controller 830. The controller 830 may be disposed on a circuit board (not shown) electrically connected to the circuit board 300 or on the circuit board 300. The controller 830 is electrically connected to the low-pass filter 810 and the high-pass filter 820, and is configured to receive a signal that has passed through the low-pass filter 810 and a signal that has passed through the high-pass filter 820. The controller 830 may be, but is not required to be, electrically connected to the FET 400 to receive an output signal from the FET 400.

[0056] The controller 830 may be configured to determine whether the controller 830 receives a signal only from the low-pass filter 810. Described below is a non-limiting example configuration of the controller 830. The controller 830 determines whether it has received a signal from the low-pass filter 810 (a first determination). If the controller 830 determines that it has received a signal from the low-pass filter 810, the controller 830 counts within a predetermined period using a timer circuit in the controller 830 or a software timer on an internal memory, and determines whether it has received a signal from the high-pass filter 820 within a predetermined period (a second determination). If the controller 830 determines that it has received a signal from the high-pass filter 820 within a predetermined period (i.e., if the controller 830 determines that it has received a signal that is not only from the low-pass filter 810), the controller 830 returns to the processing of the first determination. On the other hand, if the controller 830 determines that it has not received any signal from the high-pass filter 820 within a predetermined period, the controller 830 determines that it has received a signal only from the low-pass filter 810. In this example configuration, the controller 830 is configured to make the second determination within a predetermined period after making the first determination. Conversely, the controller 830 may be configured to make the first determination within a predetermined period after making the second determination.

[0057] If the controller 830 determines that it has received a signal only from the low-pass filter 810, this means that the controller 830 has received a signal obtained by impedance-converting a first electrical signal from the vibrating membrane 100 by irradiating the vibrating membrane 100 with infrared rays. Therefore, the controller 830 determines that the infrared rays have fallen on the vibrating membrane 100, thereby enabling detection of the infrared rays. If the controller 830 determines that it has received a signal not only from the low-pass filter 810, this means that the controller 830 has received a signal obtained by impedance-converting a second electrical signal from the vibrating membrane 100 by vibrating it by a sound wave. Therefore, the controller 830 determines that the vibrating membrane 100 is vibrated by the sound wave, thereby enabling detection of the sound wave.

[0058] The controller 830 may be further configured such that if the controller 830 determines that it has received a signal only from the low-pass filter 810, the controller 830 performs signal processing such as speech recognition processing on the signal received from the FET 400, or alternatively, performs the signal processing on the signal received from the low-pass filter 810 and the signal received from the high-pass filter 820. The controller 830 may be configured to amplify the signal received from the FET 400, or alternatively, amplify the signal received from the low-pass filter 810 and the signal received from the high-pass filter 820, and perform the above-mentioned signal processing on the amplified signals.

[0059] The controller 830 may be configured to return to the first determination based on the instruction information provided externally. Alternatively, the controller 830 may be configured so that if the controller 830 determines that it has received a signal only from the low-pass filter 810, the controller 830 uses a timer circuit in the controller 830 or a software timer on the internal memory to count within a predetermined period of time, and performs signal processing within the predetermined period of time in one of the above-mentioned ways. In this case, the controller 830 may be configured to return to the processing of the first determination after the predetermined period of time has passed. The controller 830 may not include a configuration for performing the above-mentioned signal processing, and may be configured to repeat the processing of the first determination and the processing of the second determination in sequence or in reverse order.

[0060] The above-mentioned detection sensor S and detection device D provide at least the following technical features and effects. Technical features and effects (1): The detection sensor S prevents dirt, dust and / or water from entering through the sound hole for the following reasons. The detection sensor S and the detection device D are configured to allow infrared rays to enter the housing 200 through the transmission portion 220 of the housing 200. In this way, the housing 200 has no opening for projecting infrared rays into the detection sensor S. The circuit board 300 is provided with a sound hole 310, but the hole size is small. Therefore, the detection sensor S prevents dirt, dust and / or water from entering through the sound hole 310. When the sound hole 310 is closed with a waterproof board and / or a dustproof board, the detection sensor S further prevents dirt, dust and / or water from entering through the sound hole 310.

[0061] Technical features and effects (2): The detection sensor S and the detection device D have improved versatility for the following reasons. Since the detection sensor S as described above is dustproof and / or waterproof, the detection sensor S can be installed in a location with a lot of dust and dirt and / or a place where water may adhere. In addition, the human body emits infrared rays with a peak wavelength of about 10 μm (1000 nm). Since the emitted infrared rays are transmitted through the transmission portion 220 of the detection sensor S of the detection device D and are projected onto the vibrating membrane 100, the detection device D can detect the approach of the human body (including placing the human hand on the detection device D) in the manner described above. For example, the detection device D can be incorporated into a vending machine or a ticket machine. The detection device D of this aspect can be configured to perform voice recognition processing after detecting the approach of the human body by detecting the infrared rays irradiated on the vibrating membrane 100 as described above. In this case, after detecting the approach of the person, the vending machine or the ticket machine can allow the person to purchase the product by his or her voice without touching the vending machine or the ticket machine with the human body. For example, the detection device D can be incorporated into a fire detector. The detection device D of this aspect may be configured to perform voice recognition processing after detecting a temperature change caused by a fire or other cause by detecting infrared rays irradiated on the vibratory membrane 100 as described above. In this case, after detecting the temperature change caused by a fire or other cause, the fire detector may send the processed voice data via the Internet or other lines. The detection device D may be incorporated into a security camera or other alarm device. The detection device D of this aspect may be configured to perform voice recognition processing after detecting the approach of a human body by detecting infrared rays irradiated on the vibratory membrane 100 as described above. In this case, after detecting the approach of a person, the alarm device may record the processed voice data (voice, sound, etc.) and / or send the processed voice data via the Internet or other lines.

[0062] Technical Features and Effects (3): The detection sensor S has a reduced number of components for the following reasons. Since the vibrating membrane 100 is formed using a piezoelectric film exhibiting pyroelectricity, the detection sensor S does not require both a piezoelectric film and a pyroelectric film (as in the detection sensor of the conventional example discussed above). In addition, a single FET 400 can perform impedance conversion on both the first electrical signal and the second electrical signal from the vibrating membrane 100, and the detection sensor S does not require two FETs (as in the detection sensor of the conventional example discussed above).

[0063] It should be understood that the detection sensor and the detection device described above are not limited to the embodiments described above, but can be appropriately modified within the scope of the claims. Some example modifications are described below.

[0064] As described above, the detection sensor S is configured such that the transmission portion 220 is provided in the housing 200, and the sound hole 310 is provided in the circuit board 300. However, the detection sensor of the present invention may be configured as follows. Figure 3 . More specifically, the transmission portion 320 is provided in the circuit board 300', and the sound hole 230 is provided in the top plate 211 of the housing 200'. The detection sensor S' has substantially the same configuration as the detection sensor S except for the following points. The transmission portion 320 is provided on the Z' direction side relative to the vibrating membrane 100 and is spaced apart from the vibrating membrane 100 so as to face the vibrating membrane 100. The detection device D may include a detection sensor S' instead of the detection sensor S, and the detection sensors S and S' in any of the above aspects are not limited to the detection sensors provided in the detection device D, but may be provided in other detection devices or electronic devices for use.

Claims

1. A detection sensor, comprising: a vibratable membrane composed of a piezoelectric membrane, the vibratable membrane being configured to be irradiated with infrared rays and thereby generate a first electric signal by a pyroelectric effect, and being configured to be vibrated by an acoustic wave and thereby generate a second electric signal by a piezoelectric effect; a housing accommodating the vibratable membrane and including a transmission portion configured to transmit at least infrared rays and disposed on one side in a first direction with respect to the vibratable membrane so as to face the vibratable membrane, the first direction being a thickness direction of the vibratable membrane; a circuit board fixed to the housing and disposed on the other side of the first direction relative to the vibratable membrane, the circuit board having a sound hole to input a sound wave through the sound hole; as well as A field effect transistor configured to perform impedance conversion on the first electrical signal and / or the second electrical signal received from the vibratable membrane and output the converted first electrical signal and / or the converted second electrical signal as an output signal.

2. The detection sensor according to claim 1, wherein: In a cross section along a second direction orthogonal to the first direction, a size of the acoustic hole is smaller than a size of the transmission portion.

3. The detection sensor according to claim 1 or 2, wherein: The transmission section is constituted by an optical filter configured to transmit infrared rays in a predetermined wavelength band.

4. The detection sensor according to claim 1 or 2, wherein: The vibratable membrane comprises: a film body having a first face on the one side in the first direction and a second face on the other side in the first direction; a first electrode on the first surface of the membrane body; and A second electrode is disposed on the second surface of the membrane body.

5. A detection sensor, comprising: a vibratable membrane composed of a piezoelectric membrane, the vibratable membrane being configured to be irradiated with infrared rays and thereby generate a first electric signal by a pyroelectric effect, and being configured to be vibrated by an acoustic wave and thereby generate a second electric signal by a piezoelectric effect; a housing housing the vibratable membrane and comprising: a top plate disposed on one side of a first direction relative to the vibratable membrane, the first direction being a thickness direction of the vibratable membrane; and a sound hole, the sound hole being in the top plate to input sound waves through the sound hole; a circuit board fixed to the housing, disposed on the other side of the first direction relative to the vibratable membrane and including a transmission portion configured to transmit at least infrared rays and disposed on the other side of the first direction relative to the vibratable membrane so as to face the vibratable membrane; and A field effect transistor configured to perform impedance conversion on the first electrical signal and / or the second electrical signal received from the vibratable membrane and output the converted first electrical signal and / or the converted second electrical signal as an output signal.

6. The detection sensor according to claim 5, wherein: In a cross section along a second direction orthogonal to the first direction, a size of the acoustic hole is smaller than a size of the transmission portion.

7. The detection sensor according to claim 5 or 6, wherein: The transmission section is constituted by an optical filter configured to transmit infrared rays in a predetermined wavelength band.

8. The detection sensor according to claim 5 or 6, wherein: The vibratable membrane comprises: a film body having a first face on the one side in the first direction and a second face on the other side in the first direction; a first electrode on the first surface of the membrane body; and A second electrode is disposed on the second surface of the membrane body.

9. A detection device, comprising: The detection sensor according to claim 1 or 5; a low-pass filter configured to receive the output signal from the field effect transistor, pass a signal in a frequency band obtained by impedance-converting the first electrical signal among the received output signals, and attenuate a signal in a frequency band higher than the frequency band of the signal that can pass through the low-pass filter; a high-pass filter configured to pass signals in a frequency band higher than the frequency band of the signal that can pass through the low-pass filter, and to attenuate signals in a frequency band lower than the frequency band of the signal that can pass through the high-pass filter, among the output signals; as well as A controller is configured to receive the signal that has passed through the low pass filter and the signal that has passed through the high pass filter, and determine whether the controller receives the signal only from the low pass filter.

10. The detection device according to claim 9, wherein: The controller is also configured such that if the controller determines that the controller receives a signal only from the low pass filter, the controller performs signal processing on the output signal from the field effect transistor.

11. The detection device according to claim 9, wherein: The controller is further configured such that if the controller determines that the controller receives a signal only from the low-pass filter, the controller performs signal processing on the signal that has passed through the low-pass filter and the signal that has passed through the high-pass filter.

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