Wheatstone bridge circuit gas sensor detection module and gas sensor equipped therewith

Abstract

The present invention provides a gas sensor detection module for a Wheatstone bridge circuit and a gas sensor equipped therewith. [Solution] The present invention relates to a gas sensor bridge detection module and a method for manufacturing the same, wherein the detection module is an integrated gas sensor detection module in which a gas sensor composed of a sensing element and a compensating element, each with its own resistor, is considered as four resistors and detected in a bridge circuit, the resistor of the sensing element (R1) is bonded to the sensing element (R3) to form an integrated unit, and the resistor of the compensating element (R4) is bonded to the compensating element (R2).

Description

Technical Field

[0001] The present invention relates to a gas sensor detection module of a Wheatstone bridge circuit and a gas sensor including the same.

Background Art

[0002] Circuits for detecting signals using gas sensors are classified into voltage division type and Wheatstone bridge circuits. The former has a simple circuit but low accuracy. In particular, it is affected by the external environment, and generally, a temperature compensation element may be used. The latter has relatively high accuracy but has the disadvantage of a small output and is affected by the external environment. Mainly, the resistance used behind the circuit board directly receives the influence of the external environment, and the resistance value fluctuates at any time. In the case of a long time, an aging change also occurs. Depending on the material of the resistance, for example, whether it is a metal resistance or a ceramic type, the error becomes even larger due to the difference in the temperature coefficient of resistance (TCR). In particular, in the case of a catalytic combustion type, while maintaining an operating temperature of 300 to 350 °C, and in the case of a semiconductor type, while maintaining an operating temperature of 50 to 450 °C, during a gas reaction, the resistance change becomes even larger due to the combustion or adsorption effect and operates. However, the temperature coefficients of the resistances operating at room temperature in the Wheatstone bridge circuit are different, lacking consistency in output due to the increase in the initial low-concentration detection and the concentration of the leaked gas, and the linearity may be distorted. In addition, the output signal is excessively weak, making it not only difficult to detect low concentrations but also lacking accuracy due to the influence of the external environment, and there are also many noise damages caused by increasing the amplification on the circuit. In particular, there were problems with long-term performance, reliability, and reproducibility.

Summary of the Invention

Problems to be Solved by the Invention

[0003] The gas sensor bridge detection module and its manufacturing method according to the present invention aim to improve the output sensitivity of the gas sensor, enhance low-concentration detection, and improve the stability of sensitivity.

Means for Solving the Problems

[0004] A gas sensor detection module according to one embodiment of the present invention comprises a gas sensor detection circuit that senses gas using the voltage difference between first and second voltage terminals (Vo1, Vo2), wherein the detection circuit is a gas sensor detection module of a Wheatstone bridge circuit, and may include: a sensing element 210 that constitutes the gas sensor and reacts with gas; a compensating element 260 that constitutes the gas sensor and does not react with gas; and first and second power terminals (Vs1, Vs2) that provide power to the Wheatstone bridge circuit. The sensing element 210 includes a sensing element bead 230; and a sensing element electrode wire 530 (hereinafter referred to as the "third resistance electrode wire") that connects the second voltage terminal (Vo2) and the second power terminal (Vs2) and whose resistance value changes when it reacts with a specific gas; the sensing element electrode wire 530 may include a third resistor (R3) corresponding to the resistance values ​​at both ends thereof. The compensation element 260 may include a bead 280 for the compensation element and a second resistor (R2) having a resistance value corresponding to the third resistor (R3), and may also include an electrode wire 520 for the compensation element (hereinafter referred to as the "second resistance electrode wire") connecting the first power supply terminal (Vs1) and the second voltage terminal (Vo2). The device may further include a first resistor (R1) corresponding to the third resistor (R3), and a first resistive electrode wire 510 connecting the first power supply terminal (Vs1) and the first voltage terminal (Vo1); and a fourth resistor (R4) corresponding to the second resistor (R2), and a fourth resistive electrode wire 540 connecting the first voltage terminal (Vo1) and the second power supply terminal (Vs2). The resistance of the first resistor (R1) can be varied in accordance with the change in the resistance of the third resistor (R3), and the resistance of the fourth resistor (R4) can be varied in accordance with the change in the resistance of the second resistor (R2). The first and third resistance electrode wires 510 and 530 are bonded adjacent to each other to the sensing element bead 230, and the second and fourth resistance electrode wires 520 and 540 are bonded adjacent to each other to the compensation element bead 280. The first and third resistance electrode wires 510 and 530 are preferably arranged at a distance from each other and electrically insulated from each other. The second and fourth resistance electrode wires 520 and 540 are preferably arranged at a distance from each other and electrically insulated from each other. The gas sensor is a catalytic combustion type gas sensor, and the first and third resistors (R1, R3) each comprise a first and third heating coil, wherein the first and third heating coils are arranged and bonded inside the sensing element bead 230, or at least a portion of the first and third heating coils are attached to the outside of the sensing element bead 230, and at least another portion of the first and third heating coils is exposed and bonded to the sensing element bead 230. The second and fourth resistors (R2 and R4) each include a second and fourth heating coil, and the first to fourth heating coils can generate heat when power is applied. The first resistive electrode wire 510 is attached to the outside of the sensing element bead 230, and the first resistive electrode wire 510 includes a wound wire 222 having a portion directly exposed to the outside air, and the wound wire 222 can directly react with the gas of the outside air that comes into contact with the exposed portion in a catalytic combustion reaction. The sensing element beads 230 are arranged inside the winding wire 222 and are partially coupled to the winding wire 222, forming a heat block body 240 that supports the winding wire 222. The winding wire 222 is made of a platinum-based material, and the ratio of the exposed portion of the winding wire 222 is 40-90% of the surface area of ​​the winding wire 222. The heat block body 240 includes a cover block that covers a portion of the winding wire 222, and the cover block may include at least one exposed sensing element, which is a block ring 245 that is a portion of the winding wire 222, and a bar-shaped block bar 246 that is attached to the heat block body 240 in the longitudinal direction of the heat block body 240. The winding wire 222 is one of the platinum-based metals, namely platinum (Pt), palladium (Pd), rhodium (Rh), iridium (Ir), and ruthenium (Ru), or an alloy of two or more of the aforementioned platinum-based metals. The wire diameter of the direct catalytic combustion reaction coil 220 is preferably 5 to 40 μm. The resistance of the direct catalytic combustion reaction coil 220 is preferably 2 to 20 Ω at room temperature. The coil diameter of the direct catalytic combustion reaction coil 220 is preferably 0.1 to 0.5 mm. The number of turns of the direct catalytic combustion reaction coil 220 is preferably 7 to 15 turns. The present invention further includes a direct catalytic combustion reaction coil 220 comprising the winding wire 222, the direct catalytic combustion reaction coil 220 which, when power is applied, releases power source heat to maintain a predetermined reaction operating temperature, generates combustion heat through the direct catalytic combustion reaction of the contact gas, and becomes higher than the reference operating temperature of the compensation element 260, the heat block body 240 which stores the power source heat and the combustion heat to reduce heat loss, has pores inside which it can react with the contact gas in a catalytic combustion reaction to generate additional heat. The heat block body 240 is also a columnar shape, which is one of the following: cylindrical, ellipsoidal, or polygonal prism. The heat block body 240 is divided into a plurality of blocks, and each of the plurality of blocks may include a base block 242 that serves as the internal foundation, and an adhesive block 244 that connects the base block 242 to the direct catalytic combustion reaction coil 220. The base block 242 is one of the following: a metal oxide rod (rod) which is at least one of oxidized Co, Ni, Mn, Cr, Ti, Cu, Sn, Fe, V, Ag, In, La, W, and Zn; a ceramic rod which comprises at least one of alumina and silicon dioxide; and a composite ceramic rod which comprises the metal oxide and the ceramic oxide. The adhesive block 244 may comprise at least the transition metal oxide among the transition metal oxide and precious metal powder. At least one of the first to fourth resistors (R1 to R4) is either platinum (Pt), platinum wire, or a platinum-like metal having a temperature resistance coefficient within a predetermined range. The aforementioned platinum-like metal may be one of Pd, Ir, Ru, Ni, Cr, Mn, W, Co, Ta, and Ti, or an alloy of two or more metals selected from these. The platinum wire can be formed in the center in the form of a coil, wire roll, zigzag, or plate. The gas sensor is a semiconductor gas sensor and may include a heater electrode wire 550 equipped with a heating resistor (R_h) that releases heat when power is applied. The heater electrode wire 550 may include a first heater electrode wire that passes between the first and third resistance electrode wires 510 and 530, and a second heater electrode wire that passes between the second and fourth resistance electrode wires 520 and 540. The first to fourth resistors (R1 to R4) may be formed from a single or composite metal oxide semiconductor material consisting of SnO2, TiO2, ZnO, In2O3, WO3, CuO, NiO, V2O5, Fe2O3, MnO2, Co2O3, Ag2O, ZrO2, and La2O3. The first to fourth resistors (R1 to R4) are made of the same material, and the first and third resistors (R1 and R3) can use at least one of noble metals and transition metals as a catalyst. A gas sensor according to one embodiment of the present invention may include any one of the Wheatstone bridge circuits described above as a gas sensor detection module. [Effects of the Invention]

[0005] The gas sensor detection module of the Wheatstone bridge circuit according to the present invention can improve the output sensitivity by a factor of two overall, and the reference resistance of the compensation element bead module does not fluctuate or decreases with respect to interference such as external temperature, humidity, atmospheric pressure, and electromagnetic waves, enabling ultra-precise measurements. [Brief explanation of the drawing]

[0006] [Figure 1] This is a perspective view of a catalytic combustion gas sensor to which the gas sensor detection module of the Wheatstone bridge circuit according to the present invention is applied. [Figure 2] This is a diagram showing a Wheatstone bridge detection circuit. [Figure 3] This is a plan view comparing the shape of a catalytic combustion type gas sensor, which includes a sensing element placed inside a sensing bead, as shown in Figure 1. [Figure 4] This is a diagram of the beads shown in Figure 3. [Figure 5] This is a plan view of a catalytic combustion type gas sensor that includes a sensing element positioned outside of a sensing bead. [Figure 6] This is a perspective view of an exposed type sensing element according to one embodiment. [Figure 7] Figure 6 is a cross-sectional view of a heat block or a heat block with a wound wire. [Figure 8] This figure shows a pair of sensing elements attached to the outer surface of the beads of an exposed sensing element according to another embodiment. [Figure 9] This is a plan view of a semiconductor gas sensor. [Figure 10] This is a diagram showing the stand. [Figure 11] This figure shows a semiconductor sensing element formed on a substrate. [Modes for carrying out the invention]

[0007] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. When describing with reference to the drawings, the same or corresponding components will be given the same reference numerals, and redundant explanations therein will be omitted. Terms such as "first", "second", etc. are used to describe various components, but the components are not limited by these terms. These terms are only used for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be named the second component, and similarly, the second component may also be named the first component. The term "and / or" includes combinations of multiple related described items or any one of the multiple related described items. The term "or" is interpreted as an exclusive disjunction in the context before and after, but without a direct description such as "otherwise, or, exclusive disjunction", it is interpreted in the same sense as "and / or", that is, an inclusive disjunction. Also, singular expressions include plural expressions unless explicitly stated otherwise in the context. The description that a certain component is "coupled" or "connected" to another component should be understood to mean that it may be directly coupled or connected to the other component, but there may also be other components in between. On the other hand, the description that a certain component is "directly coupled" or "directly connected" to another component should be understood to mean that there are no other components in between. This is the same for the up-down, left-right arrangement relationships. For example, when a certain component is on another component, it includes not only the case where the certain component is directly above another part, but also the case where there are other components intervening in between. The suffixes "module" and "section" for components used in the following description are given only for the convenience of preparing this specification and do not themselves confer any particularly important meaning or role. Therefore, the "module" and "section" may be used interchangeably. When such components are implemented in actual applications, two or more components can be combined into one component or one component can be subdivided into two or more components as needed. For the same or similar components throughout the drawings, the same reference numerals are given, and the detailed description of the components with the same reference numerals is replaced by and omitted from the description of the aforementioned components. In addition, the present invention encompasses all possible combinations of the embodiments presented herein. The various embodiments of the present invention are different from each other but not mutually exclusive. One embodiment of the specific shape, structure, function, and characteristics described herein can be embodied as other embodiments. For example, the components referred to in the first and second embodiments can perform all the functions of the first and second embodiments. When a certain embodiment can be embodied differently, the specific process order may be performed differently from the described order. For example, two processes described consecutively may be performed substantially simultaneously, or may proceed in the reverse order of the described order.

[0008] FIG. 1 is a perspective view of a catalytic combustion type gas sensor to which a gas sensor detection module of a Wheatstone bridge circuit according to the present invention is applied. FIG. 2 illustrates a Wheatstone bridge detection circuit. FIG. 3 illustrates a plan view for comparing the shape of FIG. 1 of a catalytic combustion type gas sensor including a detector disposed inside a bead for a sensing element. FIG. 4 illustrates the bead of FIG. 3. FIG. 5 illustrates a plan view of a catalytic combustion type gas sensor including a detector disposed outside a bead for a sensing element. FIG. 6 is a perspective view of an exposed type sensing element according to an embodiment. FIG. 7 is a cross-sectional view of a heat block body or a heat block body around which a winding wire is wound in FIG. 6. FIG. 8 illustrates a pair of detectors attached to the outer surface of a bead of an exposed type sensing element according to another embodiment. FIG. 9 illustrates a plan view of a semiconductor type gas sensor. FIG. 10 illustrates a mounting base. FIG. 11 illustrates a semiconductor type sensing element formed on a substrate body.

[0009] Referring to FIG. 2, the gas sensor detection module of this Wheatstone bridge circuit includes a detection circuit for a gas sensor that senses gas using the voltage difference between the first and second voltage terminals (Vo1, Vo2), and the detection circuit can constitute a Wheatstone bridge circuit. The gas sensor detection module of the Wheatstone bridge circuit according to the present invention can be used as a detection module for various gas sensors. This is not limited to the catalytic combustion gas sensor shown in Figure 1, but can be used for all gas sensors that use a Wheatstone bridge circuit, including catalytic combustion gas sensors with structures different from those shown in Figure 1 and semiconductor gas sensors. Typical gas sensors include catalytic combustion type gas sensors and semiconductor type gas sensors. When a flammable gas reacts with oxygen, heat is generated. The catalytic combustion gas sensor 10 converts this heat into an electrical signal to detect the gas. The catalytic combustion gas sensor 10 is used for detecting city gas and propane gas, as well as for detecting flammable toxic gases in hydrogen vehicles and factories.

[0010] The semiconductor gas sensor 20 can detect gas by utilizing the change in surface electron density or electrical resistance resulting from the chemical interaction between the gas components and the semiconductor surface. The semiconductor gas sensor 20 can sense gas by utilizing a mechanism in which oxygen ions chemically adsorbed on the semiconductor surface undergo ion exchange and electron transfer through the adsorption and desorption of external gases, thereby reducing the electrical resistance of the oxide semiconductor. The semiconductor surface is a metal oxide, but is not limited to this, and can be formed from CNTs (carbon nanotubes), carbon powder, etc.

[0011] The semiconductor gas sensor 20 is one of the following types depending on the sensor structure: Figaro type, hot wire type, thin film / thick film type, and bulk bead type. Semiconductor gas sensors detect gas using a voltage distribution method, but both catalytic combustion gas sensors and semiconductor gas sensors can detect gas using a Wheatstone bridge circuit. Bridge circuits were developed to measure the precise resistance of electronic components and are used in a variety of applications. Referring to Figure 2 and Equation 1, if the bridge voltage difference (Vout), which is the difference between the first and second voltages (Vo1-Vo2), is 0 and the three resistance values ​​are known, one of the unknown resistance values ​​can be found.

[0012]

number

[0013] This method has been extended and applied to various sensor detection circuits, such as temperature sensors, load sensors, and gas sensors, using the form shown in Equation 2, which generates an output due to unbalanced resistance. This method is more accurate than the voltage distribution method, with less error in the detected quantity.

[0014]

number

[0015] Here, the input voltage (Vs) represents the difference (Vs1-Vs2) between the first and second power supply terminals (Vs1, Vs2). If the second power supply terminal (Vs2) is grounded or 0V, Vs becomes the voltage at the first power supply terminal (Vs1). The following explanation assumes that the second power supply terminal (Vs2) is grounded.

[0016] In detection methods utilizing a Wheatstone bridge circuit, the initial output value, the bridge voltage difference (Vout), is often very small in absolute magnitude. This necessitates a large amplification of the bridge voltage difference (Vout), and this amplification process also increases noise. This is because the method is insensitive to minute changes, has poor linearity, and produces inaccurate output values ​​due to high concentrations. These limitations make it difficult for gas sensors to detect concentrations below several hundred ppm, and linearity issues arise at high concentrations in the percentage range, making them unsuitable for use in measuring instruments. However, they are very useful in industrial fields where the presence or absence of gas needs to be determined.

[0017] Referring to Figure 1, the gas sensor detection module of the Wheatstone bridge circuit may include a sensing element 210 that constitutes a gas sensor and reacts with gas, and a compensating element 260 that constitutes the gas sensor and does not react with gas. The gas sensor detection module of the Wheatstone bridge circuit may further include first and second power supply terminals (Vs1, Vs2) that supply power to the Wheatstone bridge circuit. The sensing element 210 may include sensing element beads 230 and sensing element electrode wires 530. The sensing element electrode wire 530 (hereinafter shared with the "third resistance electrode wire (R3)") connects the second voltage terminal (Vo2) and the second power supply terminal (Vs2), and its resistance changes when it reacts with a specific gas. The sensing element electrode wire 530 may be equipped with a third resistor (R3) corresponding to the resistance values ​​at both ends. The compensation element 260 may include a compensation element bead 280 and a compensation element electrode wire 520 (hereinafter shared with the "second resistance electrode wire (R2)"). The compensation element electrode wire 520 may include a second resistor (R2) having a resistance value corresponding to the third resistor (R3). The electrode wire 520 for the compensation element can connect the first power supply terminal (Vs1) and the second voltage terminal (Vo2).

[0018] The gas sensor detection module of the Wheatstone bridge circuit may further include a first resistive electrode wire 510 and a fourth resistive electrode wire 540. The first resistive electrode wire 510 includes a first resistor (R1) corresponding to the third resistor (R3), and can connect the first power supply terminal (Vs1) and the first voltage terminal (Vo1). The resistance of the first resistor (R1) can be varied in response to the change in the resistance of the third resistor (R3). The fourth resistor electrode wire 540 includes a fourth resistor (R4) corresponding to the second resistor (R2), and can connect the first voltage terminal (Vo1) and the second power supply terminal (Vs2). The resistance of the fourth resistor (R4) can be varied in response to the change in the resistance of the second resistor (R2). Generally, the third resistor (R3) and the second resistor (R2) are located within the sensing element 210 and the compensating element 260, while the first resistor (R1) and the fourth resistor (R4) are inserted as general-purpose resistors on the back of the circuit board. In a Wheatstone bridge detection circuit, if the second resistor (R2) is placed in an environment similar to that of the third resistor (R3) and used as the reference resistor, the influence of external temperature, humidity, atmospheric pressure, electromagnetic waves, etc., can be minimized or eliminated during signal detection. However, the balance condition of the bridge circuit is the product of the remaining two pairs of resistors (R1, R4), as shown in Equation 1.

[0019] In actual sensor circuit configurations, while the catalytic combustion type maintains an operating temperature of 300-350°C and the semiconductor type maintains an operating temperature of 50-450°C, the first resistor (R1) and the fourth resistor (R4) operate in a completely exposed environment as general resistive elements. In this case, significant imbalances arise due to differences in the temperature coefficient of resistance (TCR), differences in resistor materials, and differences in operating temperature ranges. Furthermore, there is often a lack of consistency in output between initial low-concentration detection and the increasing concentration of leaked gas. To minimize these issues, in practice, it is advisable to assume that each resistor has the same resistance (Ro) when calculating, and to do so in the circuit whenever possible.

[0020] Referring to Figures 1 and 3, the first and third resistance electrode wires 510 and 530 are connected to the sensing element bead 230 adjacent to each other. The second and fourth resistance electrode wires 520 and 540 are connected to the compensating element bead 280 adjacent to each other. The first and third resistance electrode wires 510 and 530 are spaced apart from each other, and the second and fourth resistance electrode wires 510 and 530 are spaced apart from each other, and they must be electrically open to each other. For example, if the first to fourth resistors (R1 to R4) are made of the same platinum wire (coil) and their shapes are substantially identical, and the positions of each bead are also made corresponding, then each resistor (R1 to R4) can maintain the same temperature at all times. Under such a configuration, each resistor (R1 to R4) will react similarly when the general external environment changes. If the sensing element reacts to leaked gas, the resistances of the third resistor (R3) and the first resistor (R1) among the multiple resistors (R1 to R4) will change similarly. This means that the magnitude of the output signal will be doubled compared to when only the resistance of the existing third resistor (R3) changes. In this case, the Wheatstone bridge circuit can be considered equivalent to a half-bridge circuit where R1 = Ro + ΔR and R3 = Ro + ΔR, and the output magnitude is expressed as shown in equation 3.

[0021]

number

[0022] If the third resistor (R3) and the first resistor (R1) are made of a material such as platinum, the TCR will behave in the same way even with high-concentration gases (in the case of catalytic combustion gas sensors, high-temperature combustion heat is generated), thus reducing signal distortion and errors and contributing to improved linearity. It is desirable that all resistors (R1 to R4) be made of the same material, and in particular, platinum is preferred. The present invention is applicable to all types of gas sensors. The present invention basically has a half-bridge detection circuit, and in the actual sensor element, the first resistor (R1) and the third resistor (R3), and the second resistor (R2) and the fourth resistor (R4) are electrically insulated but are combined together. As a result, the initial operating temperatures of the first to fourth resistors (R1 to R4) of the sensor are the same for all four.

[0023] The first and third resistors (R1 and R3) can both have the function of a sensing element, but are not limited to this; the first resistor (R1) can also be simply attached and use only temperature without any sensing function. The second and fourth resistors (R2 and R4) do not have a detection function and can only act as compensation elements. It is desirable that the second and fourth resistors (R2 and R4) be constructed with the same temperature, material, and form to improve accuracy and other factors. In the case of a catalytic combustion gas sensor, the first resistor (R1), which is a platinum wire resistor, is bonded in any form to the third resistor (R3), which is a sensing bead of the sensing element, and when they are placed in the same temperature environment as a single unit and have a nearly identical constant resistance, the sensor is complete. Similarly, the relationship between the fourth resistor (R4) and the compensating second resistor (R2) can also be realized as an integrated bead, just like the first and third resistors (R1 and R3).

[0024] When forming an integrated bead, the pair of electrodes and heating coils must not come into contact with each other (electrically insulated). Furthermore, the configuration of the first and third resistors (R1, R3), or the second and fourth resistors (R2, R4), must be symmetrical to prevent uneven temperature and resistance differences. The central portions of the first to fourth resistors (R1 to R4), which are made of platinum wire (the portions located inside the sensing element bead 230 and the compensating element bead 280, or in the central portion of those beads, respectively), can be simple wire-like, coil-like, or have a variety of shapes. The first to fourth resistors (R1 to R4) can be placed at any position on the sensing element bead 230 and the compensating element bead 280, for example, any part of the top, bottom, left, or right of each bead, but it is desirable that the resistors be placed at corresponding positions. At least one of the sensing element bead 230 and the compensating element bead 280 can have a variety of shapes as a whole, such as linear, elliptical, or curved.

[0025] The first to fourth resistors (R1 to R4) are preferably made of materials other than platinum, such as Pd, Ir, Ru, Ni, Cr, Mn, W, Co, Ta, and Ti metals, or an alloy of two or more of these (including platinum), and have a temperature resistance coefficient similar to that of platinum wire. It is desirable that all of the first to fourth resistors (R1 to R4) are made of the same material and have the same shape, and at least each pair of resistors (the first and third resistors (R1, R3), or the second and fourth resistors (R2, R4)) are made of the same material and have the same shape. The wires constituting the first to fourth resistors (R1 to R4), particularly the platinum wires, are preferably formed in one of the following shapes: coil, wire roll, zigzag, or plate, to facilitate heat generation. In the present invention, when manufacturing a catalytic combustion type gas sensor module, the sensing element (sensing element beads 230, first and third resistors (R1, R3)) or the compensating element (compensating element beads 280, second and fourth resistors (R2, R4)) are integrated by either bonding the wires constituting each resistor inside the beads as shown in Figures 3 and 4, or by attaching them to the surface of the beads as shown in Figure 5. Although Figure 5 shows only the sensing element attached to the surface of the beads, it is desirable that the sensing element be embodied as an externally exposed sensing element as shown in Figures 5 to 8, and that the compensating element be arranged inside the beads.

[0026] The sensing beads 230 ("sensing beads," "beads for sensing elements") and compensating beads 280 ("beads for compensating elements") are manufactured in a process that simultaneously dries them at room temperature, heats them at a low temperature of 200-300°C, and then heats them at a secondary high temperature of 700-1100°C. Each bead 230, 280 is a composite ceramic bead formed in a spherical shape, composed of one or more materials such as metal oxide powder or non-metal oxide powder, and may be formed to surround an internal wire, such as a platinum filament. Figure 4(a) illustrates the sensing element bead 230, and Figure 4(b) illustrates the compensating element bead 280. However, the shapes are not limited to those shown in these drawings. The sensing element bead 230 and the compensating element bead 280 can also be different shapes from each other as shown in Figure 4. The sensing element bead 230 and the compensating element bead 280 can be formed into a variety of shapes, such as spherical, elliptical, capsule-shaped, cylindrical, and plate-shaped, and may be the same shape as each other or different shapes. Referring to Figures 3 and 4, the sensing element 210 may be formed such that the surface of its beads undergoes a catalytic combustion reaction with the contact gas, changing its internal electrical resistance. The sensing element 210 may comprise a platinum filament 531 for sensing, beads 230 for sensing, and a nano-dispersed catalyst layer 231 for sensing.

[0027] The nano-dispersed catalyst layer 231 for the sensing element is placed on the surface of the sensing element beads 230. The nano-dispersed catalyst layer for the sensing element is a layer in which catalysts such as platinum and palladium are dispersed and attached to the surface of the sensing element beads 230 as nanometer-sized particles. When the catalyst in the nano-dispersed catalyst layer 231 for the sensing element comes into contact with a flammable gas (methane, propane, hydrogen, isobutane, etc.), a combustion reaction easily occurs, and the temperature of the sensing element beads 230 rises. The rise in temperature of the sensing element beads 230 further increases the temperature of the platinum filament 531 for the sensing element inside, which increases the electrical resistance of the platinum filament for the sensing element. The platinum filament 531 for the sensing element can correspond to the third resistor (R3). The first platinum filament 511 is placed inside the sensing element bead 230 and can function like the platinum filament 531 for the sensing element. That is, if a combustion reaction occurs on the surface of the sensing element bead 230, the temperature of the platinum filament 531 for the sensing element corresponding to the third resistor (R3) and the first platinum filament 511 corresponding to the first resistor (R1) will rise, and their respective electrical resistance values ​​will increase.

[0028] The platinum filament 521 for the compensating element corresponding to the second resistor (R2) and the fourth platinum filament 541 corresponding to the fourth resistor (R4) are arranged inside the compensating element bead 280. When current flows through the platinum filament 521 and the fourth platinum filament 541, each filament can release heat. When power is applied to each platinum filament 511, 521, 531, and 541 in an unreacted state, i.e., in a state where they do not react with the gas, they will each release heat. It is desirable that the temperature of the sensing element bead 230 and the compensation element bead 280 be the same. Each platinum filament 511, 521, 531, and 541 is preferably in a coil shape. Each platinum filament 511, 521, 531, and 541 is referred to as a heating coil.

[0029] The compensating body portion in Figure 5 is identical to that in Figures 3 and 4. Referring to Figure 5 and Figures 6 and 7, which are embodiments of Figure 5, the sensing element 210 can include a direct catalytic combustion reaction coil 220 and a heat block body 240. Referring to Figure 6(a), the direct catalytic combustion reaction coil 220 is in contact with the outside air, at least in part. The direct catalytic combustion reaction coil 220 can undergo a direct catalytic combustion reaction with the contact gas. The thermal block body 240 can support the direct catalytic combustion reaction coil 220. The thermal block body 240 is located inside the direct catalytic combustion reaction coil 220. Specifically, the thermal block body 240 is located inside the winding wire 222. In the direct catalytic combustion reaction coil 220 of the catalytic combustion gas sensor equipped with the coil-exposed sensing element of the present invention, it is desirable that the ratio in which the outer contour of the longitudinal cross-section of the winding wire 222 that winds the heat block body 240 is exposed to the outside is 40 to 90%. The direct catalytic combustion reaction coil 220 may include the winding wire 222 and a connecting wire 224 that connects the power supply and the winding wire 222.

[0030] The winding wire 222 is also coiled. Of the coiled portion of the winding wire 222, the exposed portion that is in direct contact with the outside air can directly react with the contact gas in a catalytic combustion reaction. The heat block body 240 is positioned inside the winding wire 222 of the direct catalytic combustion reaction coil 220, and can be partially coupled to the winding wire 222 to support it. The exposed portion of the winding wire 222 is 40-90% of its surface area. If the exposed portion of the winding wire 222 is less than 40%, the catalytic combustion reaction between the winding wire 222 and the contact gas becomes excessively small, resulting in a minute change in resistance. If the exposed portion of the winding wire 222 is greater than 90%, excessive heat is released into the air when the operating temperature of the winding wire 222 is maintained, leading to increased power consumption. This reduces the bonding force between the winding wire 222 and the heat block body 240, causing the winding wire 222 and the heat block body 240 to easily separate. For these reasons, it is desirable that the exposed portion of the winding wire 222 be between 40-90%.

[0031] The direct catalytic combustion reaction coil 220 is preferably one of the platinum-based metals, platinum (Pt), palladium (Pd), rhodium (Rh), iridium (Ir), and ruthenium (Ru), or an alloy of two or more platinum-based metals. Such a platinum-based metal alone or an alloy can provide a catalytic function that burns a flammable gas (contact gas) with oxygen at high temperatures. That is, since the platinum-based metal itself burns the flammable gas, it is not necessary to form a nano-dispersed catalyst layer for the sensing element of an existing sensing element. Throughout this specification, "direct catalytic combustion reaction" means the combustion reaction of a flammable gas due to the catalytic function of the direct catalytic combustion reaction coil 220. "Direct catalytic combustion reaction" and "direct combustion reaction" are used interchangeably. "Direct catalytic combustion reaction" means the catalytic combustion reaction of the direct catalytic combustion reaction coil 220. "Direct catalytic combustion reaction" is simply referred to as "direct combustion reaction." "Catalytic combustion reaction" is simply referred to as "combustion reaction." The wire diameter of the direct catalytic combustion reaction coil 220 is preferably 5 to 40 μm. The resistance of the direct catalytic combustion reaction coil 220 is preferably 2 to 20 Ω (ohm) at room temperature. The coil diameter of the direct catalytic combustion reaction coil 220 is preferably 0.1 to 0.5 mm. The number of turns of the direct catalytic combustion reaction coil 220 is preferably 7 to 15 turns. These specifications allow for compatibility with existing catalytic combustion gas sensors.

[0032] The direct catalytic combustion reaction coil 220 must perform operations such as catalytic combustion reactions while being maintained at a specific temperature. This specific operating temperature is referred to as the "reaction operating temperature." The compensation element 260 must serve as a reference for the sensing element 210, and therefore must be maintained at a specific reference temperature (hereinafter referred to as the "reference operating temperature"). It is desirable that the reference operating temperature be the same as the reaction operating temperature. The direct catalytic combustion reaction coil 220 releases power-induced heat (resistive heat) when a power source (not shown) is applied, allowing the direct catalytic combustion reaction coil 220 and / or the sensing element 210 (in particular, meaning the heat block body 240) to maintain the reaction operating temperature. Since the direct catalytic combustion reaction coil 220 directly reacts with the contact gas, it is desirable that at least the direct catalytic combustion reaction coil 220 maintains the reaction operating temperature. However, since catalytic combustion also occurs in the heat block body 240, which is in contact with the outside like the direct catalytic combustion reaction coil 220, it is even more desirable that the heat block body 240 also maintains the reaction operating temperature.

[0033] The reaction operating temperature is a specific temperature within the range of 300-350°C. The reaction operating temperature is determined by the type of gas being detected. The heat of combustion of the contact gas due to the direct catalytic combustion reaction in the direct catalytic combustion reaction coil 220 causes the temperature of the direct catalytic combustion reaction coil 220 to rise above the reaction operating temperature. Referring to Figure 6, the thermal block 240 can be positioned inside the direct catalytic combustion reaction coil 220 to support it. The thermal block 240 can be coupled to a portion of the direct catalytic combustion reaction coil 220. The thermal block 240 is cylindrical, but not limited to this, and can also be ellipsoidal or polygonal prism-shaped. The heat block body 240 in this embodiment can reduce heat loss by storing power supply heat and combustion heat. It can also play a significant role in the propagation and diffusion of the direct catalytic combustion reaction in the direct catalytic combustion reaction coil 220.

[0034] Referring to Figure 7(a), it is desirable that the heat block body 240 has multiple pores 248 and / or internal passages 249 inside. The permeability provided by the multiple pores 248 and internal passages 249 can provide an effect of increasing the surface area that allows the combustion reaction of flammable gases to occur inside the heat block body 240. In particular, the flammable gases are diffused into the interior of the heat block body 240 through the internal passages 249. The heat block 240 should preferably be made of a ceramic material with large particles, making it lightweight while maintaining structural strength. The heat block 240 should also preferably be made of a material capable of co-catalyzing function. This co-catalyzing function allows it to assist the catalytic combustion reaction of the direct catalytic combustion reaction coil 220, contributing to the diffusion reaction and heat retention of the catalytic combustion.

[0035] The thermal block body 240 can be formed from a sintered body. The material of the thermal block body 240 can be a composite ceramic composed of one or a combination of most metal oxides (oxides of Co, Ni, Mn, Cr, Ti, Cu, Sn, Fe, V, Ag, In, La, W, Zn, etc.), alumina, and silicon dioxide. These materials have excellent catalytic properties, far-infrared radiation properties, and long-term thermal stability. Metal oxides can undergo catalytic combustion reactions with the contact gas, releasing reaction heat. Such reaction heat can further increase the resistance of the winding wire 222, thereby further increasing the sensitivity of the gas sensing.

[0036] The particle size of the sintered material for the heat block body 240 is suitable to be between 0.1 μm and 0.4 mm. If the particle size is smaller than 0.1 μm, the permeability will be poor, and if it is larger than 0.4 mm, molding may become difficult. To ensure the permeability of the heat block body 240, it is advantageous if the material itself has many pores and a large non-surface area. To ensure permeability, an organic binder or carbon material can be mixed into the sintered body material. This allows for the creation of ventilation channels as carbon dioxide and water vapor escape during the heat treatment process. Referring to Figure 7, the thermal block body 240 is divided into multiple blocks. The thermal block body 240 may include at least a base block 242 and an adhesive block 244.

[0037] The base block 242 can serve as the internal base of the heat block body 240. The adhesive block 244 can directly bond the base block 242 to the catalytic combustion reaction coil 220. The base block 242 is also a cylindrical rod. Depending on the material, the base block 242 may be one of the following: a metal oxide rod, a ceramic rod, or a composite ceramic rod. The metal oxide rod is formed from a material comprising at least one of oxidized Co, Ni, Mn, Cr, Ti, Cu, Sn, Fe, V, Ag, In, La, W, and Zn. The ceramic rod is formed from a material comprising at least one of alumina and silicon dioxide. The composite ceramic rod is formed from a material comprising a metal oxide and a ceramic oxide. The adhesive block 244 is molded from a material comprising a transition metal oxide. The adhesive block 244 is molded from a material comprising a transition metal oxide and / or noble metal powder. Noble metal powder has good reactivity with the contact gas, but its high cost makes it difficult to include a large portion. Non-oxide metal powders are further provided in the adhesive block 244, but these non-oxide metal powders all become oxides during the high-temperature heat treatment process, acquiring both electrical insulation and catalytic properties.

[0038] Figures 7(b) and 7(c) illustrate the winding wire 222 wound around the adhesive block 244. As shown in Figures 7(b) and 7(c), both ends of the heat block 240 are not vertical but also rounded. Figure 7(b) illustrates the adhesive block 244 produced when the viscosity of the paste material is high, and Figure 7(c) illustrates the adhesive block 244 produced when the viscosity of the paste material is low. The exposure ratio of the winding wire 222 can be adjusted by changing the viscosity of the paste.

[0039] Figures 6(a) and 7 above describe a wound wire 222 that can be an embodiment of the third resistor (R3) and the first resistor (R1). The sensing element electrode wires 530 and the first resistance electrode wire 510 in Figures 6(b) and 6(c) can correspond to the direct catalytic combustion reaction coil 220 in Figure 6(a), respectively. Furthermore, the third and first winding wires 531 and 511 in Figures 6(b) and 6(c) can correspond to the winding wire 222 in Figure 6(a), respectively. Also, the heat block body 240 and / or the base block 242 and adhesive block 244 in Figure 6(a) can correspond to the sensing element beads 230. Figure 6(b) shows a configuration in which two heat blocks 240 are provided, namely the first and second heat blocks 240-1 and 240-2. The first heat block 240-1 is positioned inside the sensing element electrode wire 530, and the second heat block 240-2 is positioned inside the first resistance electrode wire 510. It is desirable that the first and second heat blocks 240-1 and 240-2 are positioned adjacent to each other. The first and second heat blocks 240-1 and 240-2 are fixed to each other by connecting legs 249. The connecting legs 249 may be made of the same material as the heat block 240. The connecting legs 249 may be formed integrally with the heat block 240. The number, arrangement, and shape of the connecting legs 249 are flexible, and they may be in contact with or surround parts of the third and first winding wires 531 and 511. Figure 6(c) illustrates how a single heat block body 240 is shared and arranged by the sensing element electrode wire 530 and the first resistance electrode wire 510. The sensing element electrode wire 530 and the first resistance electrode wire 510, which consist of the direct catalytic combustion reaction coil 220, are not limited to those shown in Figures 6(b) and 6(c), but are arranged in a double helix that shares a single heat block 240 but is twisted relative to each other, as shown in Figure 6(c). Of course, the sensing element electrode wire 530 and the first resistance electrode wire 510 must be electrically insulated. The attachment of first and third resistors (R1, R3), which can constitute a sensing element, to the surface of the sensing element bead 230 is achievable in various forms, one of which is illustrated in Figure 8.

[0040] The sensing element bead 230 is a rectangular parallelepiped, as shown in Figure 8, but is not limited to this. The sensing element bead 230 can correspond to the heat block body 240 described above. The first and third resistors (R1, R3) are attached to positions corresponding to the outer surface of the sensing element bead 230. Semiconductor gas sensors are classified into two types: hot-wire semiconductor gas sensors with their own heaters, and non-hot-wire semiconductor gas sensors without their own heaters, such as thin-film, thick-film, or bulk-sintered type sensors. The hot-wire semiconductor gas sensor can have the same structure as the catalytic combustion gas sensor described above. An internal platinum coil acts as a heating element, ensuring that the beads are placed at the operating temperature.

[0041] A non-thermal-wire semiconductor gas sensor may be equipped with a separate heater. Referring to Figure 10, two sensing elements (first and third resistors (R1, R3)) can be formed on a single substrate, and a heater (R_h1, R_h2) can be formed in the center. The heater is located on the back surface of the substrate. The sensor operating temperature is transmitted similarly to the sensing element and the compensating element to ensure they reach the same temperature. The second and fourth resistors (R2, R4) should preferably be made of semiconductor material, similar to the sensing element (first and third resistors (R1, R3)), and have the same specifications. No catalyst should be added during the manufacturing of the second and fourth resistors (R2, R4). They can be integrated into a single unit, similar to a catalytic combustion system.

[0042] The beads of non-hot-wire semiconductor gas sensors can be circular or elliptical, like those in catalytic combustion sensors, or they can come in a variety of shapes and patterns, such as squares. Since non-hot-wire semiconductor gas sensors do not have their own heaters, a heater can be inserted into the center of the sensing or compensating bead. The pair of electrode wires inserted into the beads are preferably arranged symmetrically on the heater. Through the inserted electrode wires 510-540 and the sensing beads and compensating beads, a sensing element (first and third resistors (R1, R3)) or a compensating element (second and fourth resistors (R2, R4)) can be formed. The sensing element must have a catalytic combustion function.

[0043] Specifically, the first and third resistive electrode wires 510 and 530 of the semiconductor sensing element are bonded to and integrated with the sensing element bead 230. In this embodiment, unlike in a catalytic combustion gas sensor, the sensing element bead 230 is preferably made of a semiconductor material, and the same applies to the compensation element bead 280. The second and fourth resistance electrode wires 520 and 540 are also integrally bonded to the compensating element bead 280, and a coil-shaped or zigzag-shaped heater (R_h2) is placed in the central part of the bead so that it has the same operating temperature. The first to fourth resistance electrode wires 510-540 are open in the middle but are manufactured to be connected in series with semiconductor beads. The sensing and compensating elements have a heater electrode wire in the center, and on either side of it are resistor electrode wires (R1-R3, R2-R4) that form a counter-resistor. These are made of materials such as gold (Au) or platinum (Pt) that have strong heat resistance and corrosion resistance, as well as excellent electrical conductivity, and are arranged at equal intervals. In the case of a semiconductor type, the resistor (R4) and compensator (R2) beads of the compensating element are the same as those of the sensing element, but it is desirable to use materials that do not contain precious metal materials such as Pt, Pd, Rh, or Au, which have catalytic functions necessary for adsorption, desorption, and combustion. At least one of the first to fourth resistors (R1 to R4) can be a single or composite metal oxide semiconductor material such as SnO2, TiO2, ZnO, In2O3, WO3, CuO, NiO, V2O5, Fe2O3, MnO2, Co2O3, Ag2O, ZrO2, or La2O3, having the same resistance value and the same temperature coefficient of resistance. In the case of a self-heating hot-wire semiconductor used as a semiconductor gas sensor, it is manufactured in the shape shown in Figure 3. In this case, it is preferable that each bead be flatter than the three-dimensional shape shown in Figure 4. In the method of manufacturing sensing elements and compensating beads using a substrate, the substrate can be an insulator such as alumina or a flammable material. Insulating substrates become part of the element, while flammable substrates such as paper, rubber, or plastic polymers are burned off during high-temperature heat treatment. The beads used for sensing and compensating can be circular, semi-circular, square, or in various other shapes. The manufacturing methods for each type of bead are described below.

[0044] Example 1: Integrated Resistance-Based Catalytic Combustion Gas Sensor Module for Propane Gas with Dispersed Catalyst Beads Electrode resistor wires, in the form of Pt, Pd, Rh, Ir, Os, Ru, either alone or in alloys with other metals, have a diameter of 10-40 μm, a resistance of 3-20 Ω at room temperature, a coil diameter of 0.1-0.5 mm, a length of 0.3-1.2 mm, 4-12 turns, and lead wires of 0.4-0.8 mm at both ends. The sensing element coil (R3) and its resistive coil (R1), and the compensating element coil (R2) and its resistive coil (R4) can be prepared to the same specifications.

[0045] Referring to Figure 10(a), in order to manufacture the sensing element bead module, a pair of W-shaped mounting bases 700 are provided at a distance of 1.5 mm, suspended in the air, and the R1 and R3 coils are positioned in the W-shaped grooves of the mounting bases 700, respectively. At this time, the two coils are placed as close together as possible so that they do not come into contact with each other. Referring to Figure 10(b), the carrier is applied to the sensing paste so that two coils are sufficiently contained inside, as shown in Figure 4. After drying in the air for more than one hour, the sensing paste, which has become a secondary catalyst dispersion, can be further coated and dried. On the other hand, the manufacturing process for the compensation element bead module is similar to that of the sensing element bead module described above, but a compensation paste is applied as a primary coating and dried in the air. Then, a nanopaste is further coated and dried. Next, the two final heat treatments can be performed by simultaneously placing each of the sensing element and compensation element bead modules into an electric furnace at 900°C. The heating time is 1 hour, the holding time is 30 minutes, and each module is completed by natural cooling. By wedding the respective pin electrodes, a platinum coil exposed resistance integrated contact combustion gas sensor module, consisting of the sensing element module and the compensation element module, can be completed.

[0046] Example 2: Manufacturing of a platinum coil exposed, resistance-integrated catalytic combustion gas sensor module for methane gas. In this embodiment, almost all processes are the same as in Embodiment 1, except for the sensing element bead module, which is the only difference. As shown in Figure 5, the outsides of the two coils (R1 and R3) are exposed, and the sensing paste is applied only once so that the common insides are bonded together. They can be dried in the air for more than one hour. The final heat treatment and pin electrode connection can be carried out as in Example 1.

[0047] Example 3: Manufacturing of a resistive-integrated semiconductor carbon monoxide gas sensor module Heater wires, either in the form of Pt, Pd, Rh, Ir, Os, or Ru alone or in alloys with other metals, have a diameter of 10-40 μm, a resistance of 3-20 Ω at room temperature, a coil diameter of 0.1-0.5 mm, a length of 0.3-1.2 mm, 4-12 turns, and lead wires of 0.4-0.8 mm at both ends. All electrode wires are made of the same material as the heater wires, but gold (Au) wire is also possible. In this implementation, gold wire will be used. As shown in Figure 11, the sensing element bead module may have a heater coil in the center and sensing element (R3) electrode wires and their corresponding resistor (R1) electrode wires on both sides. The spacing between the sensing element (R3) electrode wires can be 0.01 to 0.1 mm, and they can be positioned close to the heater coil without making contact. The corresponding resistor (R1) electrode wires can also be positioned on the opposite side, similar to the sensing element (R3) electrode wires. When performing this work, a substrate 600 as shown in Figure 11 can be used to form a hemispherical or thin-thick elliptical columnar detection body on it. The substrate can be a heat-resistant general ceramic plate or a flammable paper or polymer material that burns and disappears when subjected to high-temperature heat treatment. In this case, general paper was used.

[0048] A bead module for an integrated semiconductor carbon monoxide gas sensor containing a resistor can be formed by coating a SnO2 metal oxide semiconductor paste with a 5% by weight Pd catalyst added. The bead module for the compensating element, consisting of the compensating element (R2) electrode wire and its resistor (R4), can also be manufactured using the same heater coil and electrode wire. However, the paste used here can be the same SnO2 paste without the addition of a catalyst. After drying each bead module in air for 1 to 3 hours, the heat treatment can be performed by simultaneously placing each sensing element and compensating element bead module into an electric furnace at 900°C. The heating time is 1 hour, the holding time is 30 minutes, and each module is completed by natural cooling. A resistive integrated semiconductor carbon monoxide gas sensor module, consisting of the sensing element module and the compensating element module, can then be completed by welding to the respective pin electrodes. Referring to Figure 1, a gas sensor equipped with a Wheatstone bridge circuit gas sensor detection module may further include, in addition to the detection module described above, a sensor body 30 and a plurality of electrode poles 110. The sensor body 30 is packaged in a metal shield (not shown). The sensor body 30 may be fitted with a mesh cover (not shown) that allows gas to enter and exit. The side surface of the sensor body 30 is stepped to accommodate the mesh cover.

[0049] Multiple electrode poles (110:111~114, etc.) are arranged to penetrate the sensor body 30. It is preferable that the multiple electrode poles 110 be made of a metallic conductive material. The lower sides of the multiple electrode poles 110 are connected to a sensing circuit as shown in Figure 2. The sensing circuit is a circuit capable of measuring at least one of current, voltage, and resistance, or measuring the on / off state of current, and may include a Wheatstone bridge circuit. Referring to Figures 1 and 2, the semiconductor and catalytic combustion combined gas sensor may further include a shut-off plate 40. When the sensing module 120 undergoes catalytic combustion with the gas, its temperature rises further. The shut-off plate 40 blocks the radiant heat from the sensing module 120, preventing the high heat of the sensing module 120 from affecting the compensation module 140. In a Wheatstone bridge detection circuit type gas sensor, by making the compensation element corresponding to the reference resistor have the same operating temperature, material, and shape as the sensing element, external influences such as temperature, humidity, atmospheric pressure, and other contaminants can be eliminated compared to using a normal general-purpose resistive element. This improves the accuracy and stability of the output value and significantly enhances long-term reliability. Furthermore, by bonding the resistance of the sensing element to the sensing element bead, the resistance of the resistance material can undergo the same reaction as the sensing element, thereby increasing the detection sensitivity by up to two times. This is advantageous for detecting low concentrations of gas and can reduce noise signals caused by amplification of the output signal.

[0050] The present invention can be embodied in hardware or software. The invention can also be embodied as computer-readable code on a computer-readable recording medium; that is, in the form of a recording medium containing computer-executable instructions. Computer-readable media include all kinds of media on which data readable by a computer system is stored. Computer-readable media may include computer recording media and communication recording media. Furthermore, although preferred embodiments of the present invention have been illustrated and described above, it goes without saying that the present invention is not limited to the specific embodiments described above, and that various modifications can be made by those skilled in the art without deviating from the gist of the present invention as claimed in the patent claims. Such modifications should not be understood individually from the technical idea or prospects of the present invention. [Explanation of Symbols]

[0051] 30: Sensor body 40: Barrier plate 210: Sensing properties 230: Beads for sensing elements 260: Compensation element 280: Beads for compensation element

Claims

1. The device includes a gas sensor detection circuit that senses gas using the voltage difference between the first and second voltage terminals, and the detection circuit is a gas sensor detection module of a Wheatstone bridge circuit that constitutes a Wheatstone bridge circuit. The gas sensor comprises a sensing element that reacts with gas, The gas sensor comprises a compensation element that does not react with the gas, Includes first and second power supply terminals that supply power to the Wheatstone bridge circuit, The sensing element includes a bead for the sensing element, The device comprises an electrode wire for a sensing element that connects the second voltage terminal and the second power supply terminal, and whose resistance changes when it reacts with a specific gas, The electrode wire for the sensing element is equipped with a third resistor corresponding to the resistance values ​​at both ends thereof. The aforementioned compensation element includes a bead for the compensation element, The device comprises a second resistor having a resistance value corresponding to the third resistor, and an electrode wire for a compensation element connecting the first power supply terminal and the second voltage terminal, A first resistive electrode wire connecting the first power supply terminal and the first voltage terminal, comprising a first resistor corresponding to the third resistor, The present invention further includes a fourth resistor corresponding to the second resistor, and a fourth resistive electrode wire connecting the first voltage terminal and the second power supply terminal, A gas sensor detection module in a Wheatstone bridge circuit, wherein the resistance of the first resistor is variable in response to the change in the resistance of the third resistor, and the resistance of the fourth resistor is variable in response to the change in the resistance of the second resistor.

2. The gas sensor detection module of a Wheatstone bridge circuit according to claim 1, wherein the first and third resistive electrode wires are bonded adjacent to each other to the sensing element bead, and the second and fourth resistive electrode wires are bonded adjacent to each other to the compensating element bead.

3. The aforementioned gas sensor is a catalytic combustion type gas sensor, The first and third resistors each comprise the first and third heating coils, The first and third heating coils are, The elements that are arranged and bonded inside the aforementioned sensing element beads, and A gas sensor detection module for a Wheatstone bridge circuit according to claim 2, wherein at least a portion of the first and third heating coils is attached to the outside of the sensing element bead, and at least another portion of the first and third heating coils is exposed and bonded to the sensing element bead.

4. The second and fourth resistors each comprise the second and fourth heating coils, The gas sensor detection module of the Wheatstone bridge circuit according to claim 3, wherein the first to fourth heating coils generate heat when power is applied.

5. The first resistive electrode wire is attached to the outside of the sensing element bead. The first resistance electrode wire comprises a wound wire having a portion directly exposed to the outside air, The winding wire undergoes a direct catalytic combustion reaction with the gas in contact with the exposed portion of the external air, as described in claim 3, for the gas sensor detection module of the Wheatstone bridge circuit.

6. A gas sensor detection module for a Wheatstone bridge circuit according to claim 3, wherein at least one of the first to fourth resistors is platinum, platinum wire, and a platinum-like metal having a temperature resistance coefficient within a predetermined range.

7. The aforementioned gas sensor is a semiconductor gas sensor, The heater electrode wire further includes a heating resistor that releases heat when power is applied, The heater electrode wire includes a first heater electrode wire that penetrates between the first and third resistance electrode wires, A second heater electrode wire passing through the second and fourth resistance electrode wires, A gas sensor detection module for a Wheatstone bridge circuit according to claim 2, comprising:

8. The gas sensor detection module for a Wheatstone bridge circuit according to claim 7, wherein the first to fourth resistors are made of a metal oxide semiconductor material consisting of one or a combination of SnO2, TiO2, ZnO, In2O3, WO3, CuO, NiO, V2O5, Fe2O3, MnO2, Co2O3, Ag2O, ZrO2, and La2O3.

9. The first to fourth resistors are made of the same material. The gas sensor detection module for a Wheatstone bridge circuit according to claim 8, wherein the first and third resistors use at least one of a noble metal and a transition metal as a catalyst.

10. A gas sensor comprising a gas sensor detection module of a Wheatstone bridge circuit as described in any one of claims 1 to 9.

Images