JP6314530B2 - Pressure sensor and pressure detection device - Google Patents

Description

  The present invention relates to a pressure sensor.

  Pressure sensors are known that measure pressure by converting the deflection of the thin film caused by the pressure difference between two spaces separated by the thin film into an electrical signal. For example, Patent Document 1 discloses a technique for detecting the amount of bending of a thin film from a change in capacitance formed by a conductive thin film and an electrode provided opposite to the thin film. .

JP-A-6-018345

  In order to detect the amount of deflection of the thin film, the capacitance must be continuously measured. In order to continue operating the pressure sensor, it is necessary to continue to supply power, resulting in an increase in power consumption. The pressure sensor is often used in a sealed space. In this case, it is difficult to receive power supply from outside the sealed space, and it is necessary to use a battery or the like as a power source. In order to replace the battery, it is necessary to take out the sensor from the sealed space. However, if the power consumption is large, the replacement is frequently performed. Therefore, it is necessary to use a battery having a large capacity, leading to an increase in cost.

  On the other hand, it is also considered to solve this problem by using a so-called energy harvesting technique in which neither wiring nor a battery is used. In the energy harvesting technique, an element having a transducer that converts vibration into electric power and a capacitor that stores electric power generated by the transducer is used to obtain electric power necessary for the sensor. However, such a transducer still has low power conversion efficiency, and the element size becomes large. Therefore, an installation space must be ensured, and costs for production are increased.

  Therefore, even if the energy harvesting technique is used, after all, it is desired to suppress the power consumption of the pressure sensor as much as possible and to reduce the size and cost of the element including the transducer and the capacitor.

  One of the objects of the present invention is to suppress power consumption when operating a pressure sensor.

  According to an embodiment of the present invention, a flexible portion having a first surface and a second surface, having a conductive portion on the first surface side, and a fixing portion for fixing at least a part of the periphery of the flexible portion. And a first chamber formed on the first surface side of the flexible portion and having a contact detection surface having conductivity at a position corresponding to the conductive portion, and formed on the second surface side of the flexible portion. A second chamber separated from the first chamber by the flexible portion; and an opening connecting at least one of the first chamber and the second chamber and an external space, the flexible portion The amount of deflection changes due to a change in the pressure difference between the first chamber and the second chamber, and the contact between the conductive portion and the contact detection surface is switched by the deflection of the flexible portion. A pressure sensor is provided. According to this, the power consumption at the time of operating a pressure sensor can be suppressed.

  The first chamber includes: a first substrate having the flexible portion and the fixing portion; and a second substrate having the contact detection surface and bonded to the first substrate and the first surface. , And may be formed between the first substrate and the second substrate. According to this, since a conductive part and a contact detection surface can be made to oppose by joining the 2nd board | substrate which has a contact detection surface with a 1st board | substrate, a pressure sensor can be manufactured easily.

  The apparatus may further include a third substrate bonded to the first substrate on the second surface side, and the second chamber may be formed between the first substrate and the third substrate. According to this, since a 2nd chamber can be formed by joining a 3rd board | substrate to a 1st board | substrate, a pressure sensor can be manufactured easily.

  The opening may be provided in the first substrate and connect the first chamber and the external space. According to this, since an opening part can be formed collectively when forming a 1st chamber, a pressure sensor can be manufactured easily.

  The opening may be provided in the second substrate and connect the first chamber and the external space. According to this, the 2nd board | substrate with which the opening part was formed previously can be joined to a 1st board | substrate, and a pressure sensor can be manufactured easily.

  A through electrode that electrically connects the conductive layer provided outside the first chamber of the second substrate and the contact detection surface may be formed on the inner surface of the opening. According to this, the second substrate can be formed in advance by forming the through electrode having the opening in the second substrate, and the second substrate can be bonded to the first substrate. The pressure sensor can be easily manufactured.

  The conductive portion protrudes from the first surface. According to this, the adjustment of the pressure value to be detected can be adjusted by the conductive portion.

  When there is no pressure difference between the first chamber and the second chamber, the conductive portion and the contact detection surface are in contact with each other, and the pressure in the first chamber is equal to or higher than a predetermined pressure value than the pressure in the second chamber. When it is large, the conductive portion and the contact detection surface may be separated from each other. According to this, power consumption can be greatly reduced when used in a measurement environment in which an abnormal value is obtained if the pressure is reduced too much.

  A plurality of the conductive portions are formed on the first surface side of the flexible portion, and the distance of at least one of the conductive portions from the fixed portion is different from the distance of the other conductive portions from the fixed portion. The contact detection surface may be provided corresponding to each of the conductive portions. According to this, a plurality of pressure values can be detected.

  A plurality of the conductive portions are formed on the first surface side of the flexible portion, and the protruding amount of at least one of the conductive portions from the first surface is different from the first surface of the other conductive portions. Unlike the protrusion amount, the contact detection surface may be provided corresponding to each of the conductive portions. According to this, the pressure value which should be detected can be adjusted with the protrusion amount of an electroconductive part.

  A plurality of the conductive portions are formed on the first surface side of the flexible portion, and the contact detection surface is provided corresponding to each of the conductive portions, and the flexible portion is not bent. The distance from the flexible part to at least one of the contact detection surfaces may be different from the distance to the other contact detection surface. According to this, the pressure value which should be detected can be adjusted with the position of a some electroconductive part.

  The pressure sensor described above formed in a sealed space, and a detection unit that detects contact between the conductive unit and the contact detection surface based on the presence or absence of conduction between the conductive unit and the contact detection surface, The pressure is characterized in that the first chamber and the sealed space are connected via the opening, and when the pressure in the sealed space becomes lower than a predetermined pressure, the conductive portion and the contact detection surface come into contact with each other. A sensing device may be provided. According to this, even if the pressure sensor is used in a sealed space, the abnormal value can be notified to the user.

  According to the present invention, it is possible to suppress power consumption when operating the pressure sensor.

It is sectional drawing in the initial state of the pressure sensor which concerns on 1st Embodiment of this invention. It is sectional drawing in the pressurization state of the pressure sensor which concerns on 1st Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing method of the 1st board | substrate of the pressure sensor which concerns on 1st Embodiment of this invention. It is a figure at the time of seeing the 1st substrate in Drawing 3 (b) from the upper surface side. It is sectional drawing for demonstrating the manufacturing method of the 2nd board | substrate of the pressure sensor which concerns on 1st Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing method of the pressure sensor after the 1st board | substrate and 2nd board | substrate which concern on 1st Embodiment of this invention were joined. It is sectional drawing for demonstrating operation | movement of the pressure sensor which concerns on 2nd Embodiment of this invention. It is sectional drawing for demonstrating the pressure sensor which concerns on 3rd Embodiment of this invention. It is sectional drawing for demonstrating the pressure sensor which concerns on 4th Embodiment of this invention. It is sectional drawing for demonstrating operation | movement of the pressure sensor which concerns on 5th Embodiment of this invention. It is sectional drawing for demonstrating the pressure sensor which concerns on 6th Embodiment of this invention. It is a block diagram which shows the structure of the pressure detection apparatus which concerns on 7th Embodiment of this invention.

<First Embodiment>
Hereinafter, a pressure sensor according to a first embodiment of the present invention will be described in detail with reference to the drawings. In addition, embodiment shown below is an example of embodiment of this invention, This invention is limited to these embodiment, and is not interpreted. Note that in the drawings referred to in the present embodiment, the same portion or a portion having a similar function is denoted by the same reference symbol or a similar reference symbol (a reference symbol simply including A, B, etc. after a number) and repeated. The description of may be omitted. In addition, the dimensional ratio in the drawing may be different from the actual ratio for convenience of explanation, or a part of the configuration may be omitted from the drawing.

[Configuration of Pressure Sensor 1]
FIG. 1 is a cross-sectional view of the pressure sensor 1 according to the first embodiment of the present invention in an initial state. The pressure sensor 1 is formed by combining the first substrate 10, the second substrate 20 and the third substrate 30. In this example, the first substrate 10 is an SOI (Silicon on Insulator) substrate, and the second substrate 20 and the third substrate 30 are glass substrates.

  The first substrate 10 includes a BOX layer 13, an active layer 15, and a support layer 17. The BOX layer 13 is silicon oxide, and the active layer 15 and the support layer 17 are silicon. The active layer 15 has conductivity, and a thin central portion is formed. This thinly formed portion is referred to as a flexible portion 151. The flexible portion 151 has at least a part of the periphery fixed. A portion where the flexible portion 151 is fixed is referred to as a fixed portion 160.

  The flexible part 151 is formed in a film shape. A first chamber 110 is formed on a surface of the flexible portion 151 on the second substrate 20 side (hereinafter referred to as a first surface 1511). The first chamber 110 is connected to the external space 1000 of the pressure sensor 1 via the opening 115 and is designed to be the same as the pressure of the external space 1000. In this example, the opening 115 is formed by removing a part of the active layer 15. Note that the openings 115 may be provided at a plurality of locations.

  A sealed second chamber 120 is formed on the surface of the flexible portion 151 on the third substrate 30 side (hereinafter referred to as the second surface 1512). In this example, the second chamber 120 is set to about atmospheric pressure. When a structure such as a wall surface is present near the measurement object, such as when the pressure sensor 1 is used in a sealed space, the structure may be used as a substitute for the third substrate 30. That is, the structure and the support layer 17 of the first substrate 10 may be bonded so that the second chamber 120 is formed.

  In this way, the first chamber 110 and the second chamber 120 are spaces separated by the flexible portion 151. Therefore, the flexible portion 151 bends due to the pressure difference between the first chamber 110 and the second chamber 120. For example, when the pressure in the first chamber 110 becomes higher than the pressure in the second chamber 120, the flexible portion 151 bends toward the second chamber 120 (see FIG. 2).

  A conductive portion 155 having conductivity is formed on the first surface 1511 side of the flexible portion 151. The conductive portion 155 is electrically connected to the flexible portion 151 and has a shape protruding from the flexible portion 151.

  The second substrate 20 is formed with through electrodes 213 and 215 that penetrate the substrate. Electrodes 253 and 255 are formed on the first chamber 110 side of the second substrate 20, and electrodes 233 and 235 are formed on the external space 1000 side. In some cases, the through electrode may not be formed on the second substrate 20. This case will be described in detail in a sixth embodiment described later.

  The electrode 253 is electrically connected to the active layer 15. The electrode 255 is formed corresponding to the position of the conductive portion 155. In this example, the electrode 255 is in contact with the conductive portion 155 in a state where the flexible portion 151 is not bent or slightly bent toward the second chamber 120. It is formed as follows. When the conductive portion 155 and the electrode 255 are in contact with each other, they are electrically connected to each other. The through electrode 213 electrically connects the electrode 253 and the electrode 233. The through electrode 215 electrically connects the electrode 255 and the electrode 235. Therefore, when the electrode 255 and the conductive portion 155 are in contact, the electrode 233 and the electrode 235 are in a conductive state. Thus, the electrode 255 functions as a contact detection surface for detecting contact of the conductive portion 155.

  FIG. 1 shows an example where the external space 1000 is at atmospheric pressure, that is, when the first chamber 110 and the second chamber 120 have substantially the same pressure. In this case, the flexible portion 151 is hardly bent, and the conductive portion 155 and the electrode 255 are in contact with each other. In the following description, this state may be referred to as an initial state. Next, the case where the external space 1000 is at a pressure (pressurized state) higher than atmospheric pressure will be described with reference to FIG.

  FIG. 2 is a sectional view of the pressure sensor 1 according to the first embodiment of the present invention in a pressurized state. When the pressure in the external space 1000 is higher than the pressure in the second chamber 120, the pressure in the first chamber 110 also becomes higher than the pressure in the second chamber 120 through the opening 115, and the flexible portion 151 moves toward the second chamber 120. Bend. As a result, the conductive portion 155 and the electrode 255 are separated. As a result, the electrode 233 and the electrode 235 are brought out of electrical conduction.

  At this time, when the pressure difference between the first chamber 110 and the second chamber 120 becomes a predetermined value or more, the conductive portion 155 and the electrode 255 may be separated from each other. In this case, it is sufficient that the conductive portion 155 is pressed against the electrode 255 by slightly bending the flexible portion 151 toward the first chamber 110 in the state of FIG. Further, the conductive portion 155 may not be provided, and in this case, the surface of the flexible portion 151 becomes the conductive portion.

  Then, the manufacturing method of the pressure sensor 1 is demonstrated.

[Manufacturing Method of Pressure Sensor 1]
The pressure sensor 1 is formed by bonding a first substrate 10 and a second substrate 20, and a first substrate 10 and a third substrate 30. Each of the first substrate 10, the second substrate 20, and the third substrate 30 is bonded after undergoing a predetermined manufacturing process described below.

[Manufacturing Process for First Substrate 10]
FIG. 3 is a cross-sectional view for explaining the method for manufacturing the first substrate 10 of the pressure sensor 1 according to the first embodiment of the present invention. First, the first substrate 10 shown in FIG. The first substrate 10 is an SOI substrate that includes an active layer 15 of silicon and a support layer 17, and further includes a BOX layer 13 of silicon oxide sandwiched therebetween. At least the active layer 15 has conductivity.

  A part of the active layer 15 is etched to form a first depression 1501 and a second depression 1502 (FIG. 3B). At this time, the active layer 15 is etched so that a film having a predetermined thickness remains so that the BOX layer 13 is not exposed. For example, in a silicon oxide film (thermal oxide film or the like) formed on the surface of the active layer 15, portions corresponding to the first depression 1501 and the second depression 1502 are opened by photolithography, and this silicon oxide film is used as a mask. The active layer 15 may be etched by wet etching using TMAH. The etching time is determined based on the etching amount obtained from the remaining film thickness and the etching rate of the active layer 15.

  FIG. 4 is a view of the first substrate 10 in FIG. 3B when viewed from the upper surface side. Here, viewing from the upper surface side refers to the case where the first substrate 10 is viewed from the side of the first substrate 10 facing the active layer 15. In this example, the first recess 1501 is formed by etching into a circular shape. In this example, the second depression 1502 having a diameter is formed by being etched linearly from a part of the outer periphery of the first depression 1501. At this time, the conductive portion 155 (two-dot chain line) is not formed, but is shown as a position to be formed in the future.

  Returning to FIG. 3B, the description will be continued. The active layer 15 remaining in the first depression 1501 is a portion that becomes the flexible portion 151. Therefore, the remaining film thickness is appropriately set according to the usage environment of the pressure sensor. For example, when the pressure fluctuation in the measurement environment (for example, the external space 1000) is small, the flexible portion 151 needs to bend with a small pressure fluctuation, so that the remaining film is set to be thin. Conversely, when the pressure fluctuation in the measurement environment is large, the remaining film is set to be thick.

  For example, when the diameter of the flexible part 151 is about 7.6 mm, the film thickness of the flexible part 151 is set to about 10 μm to about 200 μm. If the film thickness is about 10 μm, when the pressure difference between the first chamber 110 and the second chamber 120 is about 133 Pa (1 Torr), the displacement of the central portion of the flexible portion 151 is about 6 μm. If the film thickness is about 100 μm, when the pressure difference between the first chamber 110 and the second chamber 120 is about 13300 Pa (100 Torr), the displacement of the central portion of the flexible portion 151 is about 3 μm. If the film thickness is about 200 μm, the displacement of the central portion of the flexible portion 151 is about 3.5 μm when the pressure difference between the first chamber 110 and the second chamber 120 is about 133000 Pa (1000 Torr). Become.

  Next, a conductive layer 1505 is formed on the active layer 15 (FIG. 3C). The conductive layer 1505 is, for example, aluminum. The conductive portion 155 is formed by leaving a part in the first recess 1501 using photolithography (FIG. 3D). Therefore, the film thickness of the conductive layer 1505 defines the protruding amount (height) of the conductive portion 155.

[Manufacturing Process for Second Substrate 20]
FIG. 5 is a cross-sectional view for explaining the method for manufacturing the second substrate 20 of the pressure sensor 1 according to the first embodiment of the present invention. As shown in FIG. 5A, through electrodes 213 and 215 made of a conductive material (for example, tungsten) are formed on the second substrate 20. The through electrodes 213 and 215 are formed by forming a through hole in a glass substrate and embedding a conductive material in the through hole.

  Next, an electrode 253 connected to the through electrode 213 and an electrode 255 connected to the through electrode 215 are formed (FIG. 5B). For example, the electrodes 253 and 255 may be formed using photolithography by forming a laminated structure of chromium and gold formed on the chromium in contact with the through electrode.

[Bonding of the first substrate 10 and the second substrate 20]
The first substrate 10 and the second substrate 20 thus formed are bonded with the conductive portion 155 of the first substrate 10 and the electrode 255 of the second substrate 20 facing each other. For example, anodic bonding is used for this bonding. By this bonding, the conductive portion 155 and the electrode 255 are in contact with each other. However, as described above, the conductive portion 155 and the electrode 255 are formed to be separable.

[Manufacturing Process of Pressure Sensor 1 After Bonding of First Substrate 10 and Second Substrate 20]
FIG. 6 is a cross-sectional view for explaining a method for manufacturing the pressure sensor 1 after the first substrate 10 and the second substrate 20 are bonded according to the first embodiment of the present invention. FIG. 6A shows the pressure sensor 1 after the first substrate 10 and the second substrate 20 are joined. The electrode 253 is in contact with and active with the active layer 15. The electrode 255 is in contact with the conductive portion 155 so as to be separable. The electrode 255 and the conductive portion 155 are conductive when in contact, and nonconductive when not in contact.

  In addition, the first chamber 110 is formed at a position corresponding to the first depression 1501. In addition, an opening 115 is formed at a position corresponding to the second depression 1502. The first chamber 110 is connected to the external space 1000 through the opening 155.

  Next, electrodes 233 and 235 are formed on the outer surface side of the second substrate 20 (on the side opposite to the first chamber 100) (FIG. 6B). The electrodes 233 and 235 serve as electrode pads for solder, and are formed as a laminated structure of copper, titanium, nickel, gold or the like, for example. The electrode 233 is connected to the through electrode 213. The electrode 235 is connected to the through electrode 215. The electrodes 233 and 235 are not limited to being directly connected to the through electrodes 213 and 235, and may be electrically connected via another metal wiring.

  Next, the support layer 17 is etched, and the BOX layer 13 is further etched to form the third depression 1503 (FIG. 6C). For example, the support layer 17 is etched by photolithography using the BOX layer 13 as an etching stopper, and then the BOX layer 13 is etched using the active layer 15 as an etching stopper. This etching may be dry etching or wet etching. Thereby, the flexible part 151 is formed.

  Next, the third substrate 30 is bonded to the first substrate 10 (support layer 17) so as to close the third depression 1503 (FIG. 6D). As a result, the second chamber 120 is formed in a portion corresponding to the third depression 1503. The pressure in the second chamber 120 depends on the atmosphere when the first substrate 10 and the third substrate 30 are bonded. In this example, the pressure in the second chamber 120 is set to atmospheric pressure. Therefore, the first substrate 10 and the third substrate 30 are bonded under atmospheric pressure. A plurality of the pressure sensors 1 described above are formed on one substrate. Therefore, dicing is performed to divide each pressure sensor 1 into individual pieces. In addition, about various conditions, such as the material of each structure in the manufacturing method mentioned above, and the etching method, it is an example, Comprising: It can set to various conditions. The above is the description of the manufacturing method of the pressure sensor 1.

  The pressure sensor 1 manufactured in this way has the following characteristics. As shown in FIG. 1, when the pressure difference between the first chamber 110 and the second chamber 120 is small, or when the pressure in the first chamber 110 is smaller than the pressure in the second chamber 120, the conductive portion 155 and the electrode 255 are It is in contact and conducting. On the other hand, when the pressure in the first chamber 100 becomes larger than the pressure in the second chamber 200, the flexible portion 151 bends toward the second chamber 120 as shown in FIG. 2, and the conductive portion 155 and the electrode 255 are connected. Separated and non-conducting.

  As a result, when the pressure in the external space 1000 is maintained at a level higher than the pressure in the second chamber 120 by a predetermined pressure, and the pressure difference becomes smaller than that, it is desired to detect as an abnormal value. It is effective to use the pressure sensor 1 according to one embodiment. That is, when the pressure in the external space 1000 is a normal value, the conductive portion 155 and the electrode 255 are non-conductive and consume almost no power.

  On the other hand, when the pressure in the external space 1000 decreases and becomes an abnormal value, the conductive portion 155 and the electrode 255 are brought into contact with each other and become conductive. Since the abnormal value is detected by detecting the conductive state, the power consumption at this time becomes large. However, since it is generally used on the premise that it is a normal value during normal use, if this pressure sensor 1 is used, , Can reduce power consumption.

  However, the pressure sensor 1 is not necessarily limited to the case where the initial state shown in FIG. 1 is used as an abnormal value and the pressurized state shown in FIG. 2 is used as a normal value. That is, the pressure sensor 1 may be used when the pressure difference between the first chamber 110 and the second chamber 120 is not detected as an analog value but as a digital value. This shows an example of effectively using. The digital value in this example is represented by a binary value indicating whether the pressure in the external space 1000 (first chamber 110) is equal to or higher than a predetermined pressure value.

Second Embodiment
In the first embodiment, the pressure sensor 1 is used to determine whether the pressure in the external space 1000 (first chamber 110) is equal to or higher than a predetermined pressure value. In the second embodiment, a pressure sensor 1A that can determine the pressure in the external space 1000 with more pressure values will be described.

  FIG. 7 is a cross-sectional view for explaining the operation of the pressure sensor 1A according to the second embodiment of the present invention. First, in the pressure sensor 1A, the flexible portion 151 is provided with a plurality of conductive portions 155. In the example illustrated in FIG. 7, the two conductive portions 155 of the conductive portions 155-1 and 155-2 are provided in the flexible portion 151.

  The conductive portions 155-1 and 155-2 are provided at different positions from the fixing portion 160 (for example, the inner peripheral end of the BOX layer 13 or the outer edge of the flexible portion 151) that fixes the periphery of the flexible portion 151. ing. That is, the conductive portion 155-1 and the conductive portion 155-2 are provided at positions where the amount of displacement of the flexible portion 151 is different when the flexible portion 151 is bent.

  Corresponding to each of the conductive portions 155-1 and 155-2, electrodes 255-1 and 255-2, through electrodes 215-1 and 215-2, and electrodes 235-1 and 235-2 are provided.

  In the example shown in FIG. 7A, the pressure difference between the first chamber 110 and the second chamber 120 connected to the external space 1000 is small, and the conductive portion 155-1 and the electrode 255-1 are in a conductive state. Yes, the conductive portion 155-2 and the electrode 255-2 are in a conductive state. Therefore, the electrode 233 and the electrodes 235-1 and 235-2 are in a conductive state.

  The example shown in FIG. 7B is a case where the pressure in the first chamber 110 is higher than the pressure in the second chamber 120 and is higher than the first threshold pressure value. In such a state, when the flexible portion 151 is bent, the conductive portion 155-1 close to the central portion of the flexible portion 151 having a large amount of displacement is separated from the electrode 255-1, while the fixed portion 160. The conductive portion 155-2 close to is in a conductive state while being in contact with the electrode 255-2. Therefore, the electrode 233 is electrically connected to the electrode 235-2, but is not electrically connected to the electrode 235-1.

  The example shown in FIG. 7C is a case where the pressure in the first chamber 110 becomes higher than the case shown in FIG. 7B, and becomes higher than the second threshold pressure value. In such a state, the flexible portion 151 is further bent, and the conductive portion 155-2 is also separated from the electrode 255-2. Therefore, the electrode 233 is in a non-conductive state with both the electrodes 235-1 and 235-2.

  When this pressure sensor 1A is used, for example, when the pressure of the external space 1000 is equal to or higher than the second threshold pressure value, the normal value is set, and when the pressure is equal to or higher than the first threshold pressure value and lower than the second threshold pressure value A warning value can be detected as an abnormal value when it is less than the first threshold pressure value. That is, by using the pressure sensor 1A, the pressure in the external space 1000 can be detected as a ternary digital value.

  Although the pressure sensor 1A uses the two conductive parts 155-1 and 155-2, the digital value that can be detected may be multi-valued by using more conductive parts 155.

  Further, in the state shown in FIG. 7B, in order to more reliably realize the state where the conductive portion 155-1 is separated from the electrode 235-1 while the conductive portion 155-2 is in contact with the electrode 235-2, The conductive portion 155-2 may be higher than the conductive portion 155-1 or the electrode 255-2 may be higher than the electrode 255-1. In this case, the distance from the fixing portion 160 to the conductive portion 155-1 and the distance from the conductive portion 155-2 are not necessarily different.

<Third Embodiment>
In the first embodiment, the pressure sensor 1 in which the external space 1000 and the first chamber 110 are connected via the opening 115 while the second chamber 120 is not connected to the external space 1000 has been described. In the third embodiment, a pressure sensor 1B in which the second chamber 120B is connected to the external space 1000 will be described.

  FIG. 8 is a cross-sectional view for explaining a pressure sensor 1B according to a third embodiment of the present invention. In the pressure sensor 1B, the first chamber 110B is separated from the external space 1000, and the second chamber 120B is connected to the external space 1000. The first chamber 110B is a space formed by the active layer 15B (and the flexible portion 151) and the second substrate 20, and is set to be atmospheric pressure, for example.

  An opening 325 is formed in the third substrate 30B. The second chamber 120B is connected to the external space 1000 via the opening 325. Therefore, in the pressure sensor 1B, when the pressure difference between the first chamber 110B and the second chamber 120B is small, the conductive portion 155 and the electrode 255 are in contact with each other. It is the same. On the other hand, when the pressure in the external space 1000 (second chamber 120B) becomes lower than the pressure in the first chamber 110B by a predetermined pressure value or more, the flexible portion 151 bends toward the second chamber 120B, and the conductive portion 155 and the electrode 255 is separated and becomes non-conductive.

  Note that an opening that connects the second chamber 120 </ b> B to the external space 1000 may be provided in the support layer 17. Further, when the pressure sensor 1B is used in an environment where it is not necessary to protect the flexible portion 151, the third substrate 30B may not be used. In this case, the second chamber 120 </ b> B is a space surrounded by the third depression 1503, and the opening on the external space 1000 side of the third depression 1503 is defined as an opening connected to the external space 1000. (See FIG. 6 (c)).

<Fourth embodiment>
In the first embodiment, the first chamber 110 and the external space 1000 are connected via the opening 115 formed in the active layer 15. In the fourth embodiment, a pressure sensor 1C provided with an opening at another location will be described.

  FIG. 9 is a cross-sectional view for explaining a pressure sensor 1C according to a fourth embodiment of the present invention. In the pressure sensor 1C, an opening for connecting the first chamber 110C and the external space 1000 is provided in the second substrate 20C. In this example, the through electrodes 213C and 215C are formed on the second substrate 20C. The through electrodes 213C and 215C are not formed so as to close the through holes of the second substrate 20C, but have openings 2135C and 2155C formed therein. The first chamber 110C is connected to the external space 1000 through these openings 2135C and 2155C. In this example as well, the opening 115 described in the first embodiment can be used in combination.

<Fifth Embodiment>
In the first embodiment, when the pressure difference between the first chamber 110 and the second chamber 120 is small, the pressure sensor 1 is formed so that the conductive portion 155 and the electrode 255 are in contact with each other. In the fifth embodiment, a pressure sensor 1D formed so that the conductive portion 155 and the electrode 255 are not in contact when the pressure difference between the first chamber 110 and the second chamber 120 is small will be described.

  FIG. 10 is a cross-sectional view for explaining the operation of the pressure sensor 1D according to the fifth embodiment of the present invention. FIG. 10A shows the state of the pressure sensor 1D when the pressure difference between the first chamber 110 and the second chamber 120 is small. In this example, when the flexible portion 151 is not bent, the conductive portion 155D and the electrode 255D are not in contact with each other. This may be designed such that the height of the conductive portion 155D and the electrode 255D is lower than that in the first embodiment, or the distance between the flexible portion 151 and the second substrate 20 is increased. .

  FIG. 10B shows a case where the pressure in the external space 1000 (first chamber 110) is lower than the pressure in the second chamber 120, the flexible portion 151 is bent, and the conductive portion 155D and the electrode 255D are in contact with each other. ing.

  In this pressure sensor 1D, the first chamber 110 is not connected to the external space 1000, but the second chamber 120 is connected to the external space 1000 as in the pressure sensor 1A of the second embodiment described above. It may be formed as follows.

<Sixth Embodiment>
In the sixth embodiment, a pressure sensor 1E in the case where the through electrodes 213 and 215 are not formed on the second substrate 20 will be described.

  FIG. 11 is a cross-sectional view for explaining a pressure sensor 1E according to a sixth embodiment of the present invention. In the pressure sensor 1E, the second substrate 20E extends to the outside of the first substrate 10. The second substrate 20E is provided with an electrode 255E1 that functions as a contact detection surface, and an electrode 255E2 that extends from the first chamber 110 through the opening 115 to the external space 1000 below the electrode 255E1. In addition, an electrode 235E corresponding to the electrode 235 in the first embodiment is formed on the electrode 255E2 as an electrode pad for soldering. Since the electrode 255E2 passes through the opening 115, the electrode 255E2 can extend from the first chamber 100 to the external space 1000 without being in contact with the active layer 15. By arranging the electrodes in this way, the electrodes can be drawn out to the external space 1000 without using the through electrode 215.

  The second substrate 20E is provided with an electrode 253E extending from the region sandwiched between the active layer 15 and the second substrate 20E to the external space 1000. The electrode 253 is in contact with and electrically connected to the active layer 15. Further, an electrode 233E corresponding to the electrode 233 in the first embodiment is formed on the electrode 253E as an electrode pad for soldering. By arranging the electrodes in this way, the electrodes can be drawn out to the external space 1000 without using the through electrode 213. Note that the electrode 253E may not be disposed between the active layer 15 and the second substrate 20E, but may be disposed in electrical contact with the outer surface of the active layer 15.

  Note that the presence of the electrode 253E between the second substrate 20 and the active layer 15 makes it difficult to connect the active layer 15 and the second substrate 20E, but there is no problem in bonding strength. If bonding is performed using anodic bonding, strong bonding strength can be maintained. In addition, a space may be formed along the electrode 233 and the airtightness may not be maintained. However, when the first chamber 100 is connected to the external space 1000 through the opening 115, a problem particularly occurs. Absent.

  In the sixth embodiment, the case where the through electrodes 233 and 235 are not used has been described. However, only one of the through electrode 233 and the through electrode 235 may not be used.

<Seventh embodiment>
In the seventh embodiment, a pressure detection device 100 that detects a pressure change in the external space using the pressure sensor 1 in the first embodiment described above will be described.

  FIG. 12 is a block diagram showing the configuration of the pressure detection device 100 according to the seventh embodiment of the present invention. For example, the pressure detection device 100 detects the pressure in a sealed space such as the inside of a vehicle tire. The pressure detection device 100 includes a pressure sensor 1, a detection unit 2, a transmission unit 3, and a power source 4. The receiving unit 6 and the notification unit 7 and the pressure detection device 100 constitute a pressure detection system 500.

  The power source 4 is a battery and supplies power to the detection unit 2 and the transmission unit 3. In addition, when the power source 4 is a rechargeable battery, the generator 41 may be provided separately. In the example shown in FIG. 12, the case where the generator 41 exists is shown. The generator 41 may be a transducer that converts, for example, motion and vibration accompanying rotation of a tire into electric power using a piezoelectric element or the like. In this case, the power source 4 is not limited to a rechargeable secondary battery, and may be a capacitor that stores electric power generated by the transducer.

  The detection unit 2 is connected to the electrodes 233 and 235 in the pressure sensor 1 and detects whether these electrodes are in a conductive state or a non-conductive state.

  When the transmission unit 3 detects that the electrode 233 and the electrode 235 are in a conductive state in the detection unit 2, the transmission unit 3 outputs a detection signal wirelessly. This detection signal is received by the receiving unit 6. When receiving the detection signal, the reception unit 6 notifies the notification unit 7 that the detection signal has been received. When the notification unit 7 receives the notification from the reception unit 6, the notification unit 7 notifies the user that the electrode 233 and the electrode 235 are in a conductive state in the pressure detection device 100, that is, that the conductive unit 155 and the electrode 255 are in contact with each other. Notice. The notification of the notification unit 7 may be any notification as long as it notifies the user that the pressure in the tire has become lower than a predetermined pressure. For example, the notification unit 7 may generate an alarm sound, display on a display, or the like. What is necessary is just to notify a user.

  As described above, when the pressure detection device 100 is installed in a tire and the tire pressure is to be measured, it is necessary to notify the user before the pressure in the tire decreases to the atmospheric pressure. When the pressure in the chamber 110 is reduced by 30% of the prescribed pressure of the tire or the like, the conductive portion 155 and the electrode 255 are set in contact with each other. In this setting, when the pressure sensor 1 is manufactured, for example, the pressure in the second chamber 120 may be set to about 30% reduction of the specified pressure. Further, when the pressure in the second chamber 120 is atmospheric pressure, the remaining film thickness of the flexible portion 151 is increased so that the conductive portion 155 is pressed against the electrode 255 even when the first chamber 110 is at atmospheric pressure. The bending portion 151 may be bent toward the second chamber 120 side. At this time, the height (film thickness) of at least one of the conductive part 155 and the electrode 255 may be increased instead of or in combination with the remaining film thickness of the flexible part 151.

<Eighth Embodiment>
In the pressure detection device 100 described above, a plurality of pressure sensors 1 may be used. In this case, each of the plurality of pressure sensors 1 has a different pressure in the external space 1000 (first chamber 110) when the conductive portion 155 and the electrode 255 change from a separated state to a contacted state. .

  In this way, as in the case of using the pressure sensor 1A described in the second embodiment, the pressure in the external space 1000 can be detected as a digital value of three or more values. For example, as the two types of pressure sensors 1, the pressure sensor 1 in which the conductive portion 155 and the electrode 255 are electrically connected when the pressure in the external space 1000 is equal to or lower than the first threshold pressure, and the pressure in the external space 1000 is the second threshold pressure. In the following, the pressure sensor 1 in which the conductive portion 155 and the electrode 255 are conducted is used. In this case, when the pressure in the external space 1000 is equal to or higher than the second threshold pressure value, a normal value is set. When the pressure is equal to or higher than the first threshold pressure value and lower than the second threshold pressure value, the warning value is set. When it is less than one threshold pressure value, it can be detected as an abnormal value.

  In order to change the pressure of the external space 1000 when the conductive portion 155 and the electrode 255 change from the non-conductive state to the conductive state, the thickness and size of the flexible portion 151 ( If it is circular, it is a diameter. If it is not circular, for example, the distance between the fixed portions 160), the height (thickness) of the conductive portion 155, the height (thickness) of the electrode 255, the flexible portion 151 and the first portion. At least one parameter such as the distance to the two substrates 20 and the pressure in the second chamber 120 may be made different for each pressure sensor 1. Note that the thickness of the flexible portion 151 is not limited to the thickness of the flexible portion 151 itself, and another member such as the conductive portion 155 is formed with a large area so that the flexible portion 151 is difficult to bend. May be.

DESCRIPTION OF SYMBOLS 1,1A, 1B, 1C, 1D ... Pressure sensor, 2 ... Detection part, 3 ... Transmission part, 4 ... Power supply, 6 ... Reception part, 7 ... Communication part, 10 ... 1st board | substrate, 13 ... BOX layer, 15, 15B ... Active layer, 17 ... Support layer, 20, 20C ... Second substrate, 30, 30B ... Third substrate, 100 ... Pressure sensing device, 110, 110B ... First chamber, 115, 325, 2135C, 2155C ... Opening , 120, 120B ... second chamber, 151 ... flexible part, 155, 155-1, 155-2, 155D ... conductive part, 160 ... fixed part, 213, 215, 213C, 215C ... penetrating electrode, 233, 235 235-1, 235-2, 253, 255, 255-1, 255-2, 255 D... Electrode, 500, pressure detection system, 1000, external space, 1501, first recess, 1502, second recess, 1503 ... 3rd depression Department, 1505 ... conductive layer, 1511 ... first surface, 1512 ... second surface

Claims (10)

A flexible portion having a first surface and a second surface, and having a conductive portion on the first surface side;
A fixing portion for fixing at least a part of the periphery of the flexible portion;
A first chamber formed on the first surface side of the flexible portion and having a contact detection surface having conductivity at a position corresponding to the conductive portion;
A second chamber formed on the second surface side of the flexible portion and separated from the first chamber by the flexible portion;
An opening for connecting at least one of the first chamber and the second chamber to an external space;
With
The amount of deflection of the flexible portion changes due to a change in pressure difference between the first chamber and the second chamber,
By the deflection of the flexible portion, Ri and the conductive portion and the contact or non-contact with the contact detection surface switches,
A plurality of the conductive portions are formed on the first surface side of the flexible portion,
The distance from the fixed part of at least one of the conductive parts is different from the distance from the fixed part of the other conductive parts,
The pressure sensor , wherein the contact detection surface is provided corresponding to each of the conductive portions . A flexible portion having a first surface and a second surface, and having a conductive portion on the first surface side;
A fixing portion for fixing at least a part of the periphery of the flexible portion;
A first chamber formed on the first surface side of the flexible portion and having a contact detection surface having conductivity at a position corresponding to the conductive portion;
A second chamber formed on the second surface side of the flexible portion and separated from the first chamber by the flexible portion;
An opening for connecting at least one of the first chamber and the second chamber to an external space;
With
The amount of deflection of the flexible portion changes due to a change in pressure difference between the first chamber and the second chamber,
By the bending of the flexible portion, the contact or non-contact between the conductive portion and the contact detection surface is switched,
A plurality of the conductive portions are formed on the first surface side of the flexible portion,
The amount of protrusion of the at least one conductive part from the first surface is different from the amount of protrusion of the other conductive part from the first surface,
The pressure sensor , wherein the contact detection surface is provided corresponding to each of the conductive portions . A first substrate having the flexible portion and the fixing portion;
A second substrate having the contact detection surface and bonded to the first substrate on the first surface side;
With
The first chamber, the pressure sensor according to claim 1 or 2, characterized in that it is formed between the first substrate and the second substrate. A third substrate bonded to the first substrate on the second surface side;
The pressure sensor according to claim 3 , wherein the second chamber is formed between the first substrate and the third substrate. The pressure sensor according to claim 3 or 4 , wherein the opening is provided in the first substrate and connects the first chamber and the external space. The pressure sensor according to claim 3 or 4 , wherein the opening is provided in the second substrate and connects the first chamber and the external space. A through electrode that electrically connects the conductive layer provided outside the first chamber of the second substrate and the contact detection surface is formed on the inner surface of the opening. The pressure sensor according to claim 6 . The conductive portion, the pressure sensor according to any of claims 1 to 7, characterized in that protrudes from the first surface. When there is no pressure difference between the first chamber and the second chamber, the conductive portion and the contact detection surface are in contact with each other,
9. The pressure sensor according to claim 8 , wherein when the pressure in the first chamber is larger than a pressure value in the second chamber by a predetermined pressure value or more, the conductive portion and the contact detection surface are separated from each other. The pressure sensor according to any one of claims 1 to 9 , wherein the pressure sensor is formed in a sealed space;
A detection unit that detects contact between the conductive unit and the contact detection surface based on the presence or absence of conduction between the conductive unit and the contact detection surface;
With
The first chamber and the sealed space are connected via the opening,
When the pressure in the sealed space is lower than a predetermined pressure, the pressure detecting device is characterized in that the conductive portion comes into contact with the contact detection surface.

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