Patent Application
20240295514
This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2023-032013, filed on Mar. 2, 2023; the entire contents of which are incorporated herein by reference.
Embodiments described herein relate generally to a sensor and a sensor system.
For example, there are sensors that detect gases. It is desired to improve the characteristics of the sensor.
According to one embodiment, a sensor includes an element section including a first base and a first element. The first element includes a first fixed member fixed to the first base, a first connecting member supported by the first fixed member, and a first film portion supported by the first connecting member. A second direction from the first fixed member to the first film portion crosses a first direction from the first base to the first fixed member. A first gap is provided between the first base and the first film portion. The first film portion includes a first resistance layer, a first conductive layer, and a first conductive member provided between the first resistance layer and the first conductive layer. A potential of the first conductive member is fixed. A first electrical resistance of the first resistance layer is configured to change according to a state of a detection target around the first element.
Various embodiments are described below with reference to the accompanying drawings.
The drawings are schematic and conceptual; and the relationships between the thickness and width of portions, the proportions of sizes among portions, etc., are not necessarily the same as the actual values. The dimensions and proportions may be illustrated differently among drawings, even for identical portions.
In the specification and drawings, components similar to those described previously or illustrated in an antecedent drawing are marked with like reference numerals, and a detailed description is omitted as appropriate.
As shown in
The first element 10A includes a first fixed member 21F fixed to the first base 51s, a first connecting member 21C supported by the first fixed member, and a first film portion 11F supported by the first connecting member 21C.
A first direction D1 from the first base 51s to the first fixed member 21F is defined as a Z-axis direction. One direction perpendicular to the Z-axis direction is defined as an X-axis direction. A direction perpendicular to the Z-axis direction and the X-axis direction is defined as a Y-axis direction.
For example, the first base 51s includes a first face 51F. The first face 51F extends along the X-Y plane. The first fixed member 21F is fixed to the first face 51F.
A second direction D2 from the first fixed member 21F to the first film portion 11F crosses the first direction D1. The second direction D2 is, for example, the X-axis direction.
As shown in
As shown in
The potential of the first conductive member 11c is fixed. The first conductive member 11c is set to, for example, a ground potential (GND potential).
A first electrical resistance R1 of the first resistance layer 11a changes depending on the state of the detection target around the first element 10A.
As shown in
For example, heat propagation (heat dissipation) changes depending on the state of the detection target around the first element 10A. The detection target is, for example, gas. For example, the thermal conductivity of the gas around the first element 10A depends on the elements (and/or molecules) included in the gas and their concentrations. The heat dissipation property changes depending on the state of the detection target (type and concentration of the gas), and as a result, the first electrical resistance R1 of the first resistance layer 11a changes. By detecting the first electrical resistance R1, it is possible to detect the state of the detection target (gas and change in gas concentration).
As described above, in the embodiment, the first electrical resistance R1 changes depending on the state of the detection target when the temperature of the first film portion 11F is increased by the first electric power supplied to the first conductive layer 11b.
The detection target exists in the first gap g1. The first electrical resistance R1 changes depending on the state of the detection target between the first base 51s and the first film portion 11F.
It has been found that in such a sensor 110, the signal obtained from the first resistance layer 11a (the signal corresponding to the first electrical resistance R1) tends to include noise. For example, for rising the temperature, a large current is supplied to the first conductive layer 11b. It is considered that noise included in the large current causes noise in the signal obtained from the first resistance layer 11a.
In the embodiment, the first conductive member 11c is provided between the first resistance layer 11a and the first conductive layer 11b. The first conductive member 11c whose potential is fixed functions as a shield. Thereby, the noise in the signal obtained from the first resistance layer 11a is suppressed. As a result, the detection target can be detected with high accuracy. According to the embodiment, it is possible to provide a sensor capable of improving characteristics.
In the embodiment, for example, the first conductive layer current flowing through the first conductive layer 11b in the supply of the first electric power is large. Thereby, the first film portion 11F can be effectively heated. On the other hand, the first resistance layer current flowing through the first resistance layer 11a in detecting the first electrical resistance R1 is relatively small. For example, the first conductive layer current is greater than the first resistance layer current.
Noise is likely to occur when the first conductive layer current is greater than the first resistance layer current. In the embodiment, even in such a state where noise is likely to occur, noise can be effectively suppressed by providing the first conductive member 11c.
For example, the first conductive layer current is not less than 2 times the first resistance layer current. For example, the first conductive layer current may be not less than 5 times the first resistance layer current.
The first conductive member 11c may be electrically connected to the first base 51s. The first base potential of the first base 51s may be substantially the same as the potential of the first conductive member 11c.
For example, as shown in
In the embodiment, it is preferable that the electrical resistance of the first conductive layer 11b is low and the electrical resistance of the first resistance layer 11a is high. By the resistance of the conductive layer being low, for example, the heater voltage can be lowered. The high resistance of the resistance layer can enhance the sensitivity of the gas sensor, for example.
For example, the first conductive layer 11b preferably includes at least one selected from the group consisting of Au, Al, Ti, TiN and Pt. The temperature can be effectively raised.
The first resistance layer 11a preferably includes at least one selected from the group consisting of Au, Al, Ti, TiN and Pt. Stable characteristics are easily obtained.
As shown in
For example, at least a part of the outer edge 11r of the first conductive member 11c is outside the first conductive layer 11b and the first resistance layer 11a in a plane (e.g., X-Y plane) crossing the first direction D1. For example, in the first film portion 11F, the area of the first conductive member 11c is preferably larger than the area of the first conductive layer 11b and larger than the area of the first resistance layer 11a. Stable shielding effect is obtained.
By the area of the first conductive member 11c being large, for example, non-uniformity of temperature in the first film portion 11F is suppressed. High uniformity of temperature is easily obtained.
As shown in
As shown in
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As shown in
The controller 70 is configured to detect the first electrical resistance R1 by supplying the first electric power to the first conductive layer 11b via the first connecting member 21C and the first other connecting member 21CA, for example.
The first conductive member 11c, for example, passes through the first connecting member 21C. The first conductive member 11c may not pass through the first other connecting member 21CA.
As shown in
The second element 10B includes a second fixed member 22F fixed to the second base 52s, a second connecting member 22C supported by the second fixed member 22F, and a second film portion 12F supported by the second connecting member 22C. The second base 52s may be continuous with the first base 51s. The boundary between the second base 52s and the first base 51s may be clear or unclear. The second fixed member 22F is fixed to a second face 52F of the second base 52s.
A second gap g2 is provided between the second base 52s and the second film portion 12F. The second film portion 12F includes a second resistance layer 12a. The controller 70 is configured to output a value corresponding to the difference between the second electrical resistance R2 of the second resistance layer 12a and the first electrical resistance R1 (see
The second element 10B is, for example, a reference element. For example, influences such as fluctuations in ambient temperature are suppressed. High accuracy detection is possible.
In this example, the second film portion 12F includes a second conductive layer 12b. Power need not be supplied to the second conductive layer 12b. The second conductive layer 12b may not be used for detection. The second conductive layer 12b functions, for example, as a dummy conductive layer.
In this example, the second film portion 12F includes a second conductive member 12c. The second conductive member 12c is provided, for example, between the second resistance layer 12a and the second conductive layer 12b. By the shielding effect of the second conductive member 12c, noise can be further suppressed in the signal obtained from the second resistance layer 12a.
In the embodiment, the second conductive layer 12b and the second conductive member 12c may be omitted. Alternatively, the configuration of the second element 10B may be substantially the same as the configuration of the first element 10A. The first element 10A and the second element 10B have substantially the same heat capacity and the like, which enables detection with higher accuracy.
In the sensor 111, the second element 10B may further include a second other fixed member 22FA fixed to the second base 52s and a second other connecting member 22CA supported by the second other fixed member 22FA. The second other connecting member 22CA supports the second film portion 12F. For example, the second film portion 12F is provided between the second connecting member 22C and the second other connecting member 22CA. The second film portion 12F is supported more stably. The second film portion 12F may include a second insulating member 12i.
The second embodiment relates to a sensor system. As shown in
The communicator 75 is configured to supply a signal to the outside by, for example, at least one of wired and wireless methods. The communicator 75 may acquire a control signal from the outside. The controller 70 may be controlled by an external control signal.
The embodiments may include the following configurations (e.g., technical proposals).
A sensor, comprising:
The sensor according to Configuration 1, wherein
The sensor according to Configuration 1 or 2, wherein
The sensor according to any one of Configurations 1-3, wherein
The sensor according to Configuration 4, wherein
The sensor according to Configuration 4, wherein
The sensor according to any one of Configurations 1-6, wherein
The sensor according to any one of Configurations 1-7, wherein
The sensor according to any one of Configurations 1-8, wherein
The sensor according to any one of Configurations 1-8, wherein
The sensor according to any one of Configurations 1-10, wherein
The sensor according to any one of Configurations 1-11, wherein
The sensor according to Configuration 12, further comprising:
The sensor according to Configuration 13, wherein
The sensor according to any one of Configurations 1-11, further comprising:
The sensor according to Configuration 1, further comprising:
The sensor according to Configuration 16, wherein
The sensor according to Configuration 17, wherein
The sensor according to any one of Configurations 16-18, wherein
A sensor system, comprising:
According to the embodiments, a sensor and a sensor system capable of improving characteristics can be provided.
In the specification of the application, “perpendicular” and “parallel” refer to not only strictly perpendicular and strictly parallel but also include, for example, the fluctuation due to manufacturing processes, etc. It is sufficient to be substantially perpendicular and substantially parallel.
Hereinabove, exemplary embodiments of the invention are described with reference to specific examples. However, the embodiments of the invention are not limited to these specific examples. For example, one skilled in the art may similarly practice the invention by appropriately selecting specific configurations of components included in sensors and sensor systems such as, bases, element sections, fixed members, connecting members, film portions, controllers, etc., from known art. Such practice is included in the scope of the invention to the extent that similar effects thereto are obtained.
Further, any two or more components of the specific examples may be combined within the extent of technical feasibility and are included in the scope of the invention to the extent that the purport of the invention is included.
Moreover, all sensors and all sensor systems practicable by an appropriate design modification by one skilled in the art based on the sensors and the sensor systems described above as embodiments of the invention also are within the scope of the invention to the extent that the purport of the invention is included.
Various other variations and modifications can be conceived by those skilled in the art within the spirit of the invention, and it is understood that such variations and modifications are also encompassed within the scope of the invention.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2023-032013 | Mar 2023 | JP | national |
