KR20140148167A - Device for measuring carbon dioxide - Google Patents

Abstract

A carbon dioxide sensor device is provided. According to an embodiment of the present invention, the carbon dioxide sensor device comprises: a substrate; heating patterns formed on one surface of the substrate; a solid electrolyte layer formed on the other surface of the substrate; electrode patterns formed on one surface of the solid electrolyte layer; and a passivation layer loaded on the electrode patterns. The electrode patterns includes first and second electrode patterns separated from each other and the passivation layer includes an opening to expose the second electrode patterns to the outside. A sensing material layer is loaded on the top of the opening and the heating patterns heat the substrate by receiving power from the outside.

Description

TECHNICAL FIELD [0001] The present invention relates to a carbon dioxide sensor device,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a carbon dioxide sensor device, and more particularly, to a carbon dioxide sensor device capable of reducing drive power consumption, measuring accuracy and operating speed of a sensor.

BACKGROUND OF THE INVENTION [0002] Carbon dioxide is a very stable gas chemically stable in the atmosphere and is a major cause of global warming. Therefore, the need for carbon dioxide concentration control for indoor air conditioning of buildings and automobiles including the above environmental problems is increasing, Is being studied actively.

In particular, in recent years, automobile HVAC systems will be changed to carbon dioxide refrigerant instead of freon gas, which is a typical pollutant of global warming, in advanced countries including Europe. As a result of evaluation by these automobile companies, it was confirmed that the change in the CO ₂ concentration in the vehicle was caused by the change of the refrigerant, and the necessity of the CO ₂ gas sensor system to be applied to the interior of the vehicle was confirmed.

In addition, the concentration of CO _2, which makes the body feel uncomfortable, is more than 1,000ppm. It causes respiratory and pulsation, blood pressure and pulse pressure to rise due to the effects on the human body when inhaled, and causes symptoms such as headache, boredom, dizziness and discomfort do. Therefore, it may cause drowsiness driving due to the increase of CO ₂ concentration in the long-term driving, and may cause child and pet choking by summer and winter heater.

The optical method (NDIR method) is the most widely used method for measuring the concentration of carbon dioxide gas present in the air, and this method has an advantage of being excellent in selectivity, quantitativeness and reproducibility. However, Space is required and there are restrictions on the application of various systems due to the physical size of the components and filters. In addition, since the driving part and the measuring part are very expensive and the configuration of the processing part for the control is complicated, the overall price of the sensor is inevitably high. In particular, when exposed to harsh environments, the optical system is liable to be contaminated, and thus the use range is limited to a relatively stable indoor space.

In recent years, an electrochemical carbon dioxide sensor using a solid electrolyte has been proposed. However, since it is essential to maintain a high operating temperature for smooth operation, it is a main cause of deterioration in overall durability due to deterioration by a heating means. Also, when using a solid electrolytic sintered body of a pellet type, there is a problem that the initial operation time is slowed due to the relatively high power consumption and the arrival of the thermal equilibrium state due to the electrolyte thickness.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a carbon dioxide sensor device having a low power consumption and capable of improving measurement accuracy.

Another object of the present invention is to provide a carbon dioxide sensor device capable of quickly reaching a thermal equilibrium state, shortening an initial operation time, and further increasing reliability of carbon dioxide concentration measurement.

The technical objects of the present invention are not limited to the above-mentioned technical problems, and other technical subjects not mentioned can be clearly understood by those skilled in the art from the following description.

According to an aspect of the present invention, there is provided a carbon dioxide sensor device including a substrate, a heating pattern formed on one surface of the substrate, a solid electrolyte layer formed on the other surface of the substrate, And a passivation layer laminated on the electrode pattern, wherein the electrode pattern includes a first electrode pattern and a second electrode pattern that are spaced apart from each other, and the passivation layer exposes the second electrode pattern to the outside And a sensing material layer is laminated on the upper portion of the opening, and the heating pattern is supplied with power from the outside to heat the substrate.

And a diffusion preventing layer formed on the first electrode pattern to separate the first electrode pattern from the passivation layer.

And a pad electrode having one end of the electrode pattern extended and exposed to the outside of the passivation layer, wherein one surface of the pad electrode is in contact with the substrate.

The solid electrolyte layer may be formed in a thick film form on the substrate.

The sensing material layer may comprise a noble metal or carbonate.

And a porous protective layer stacked on the sensing material layer.

The porous protective layer may comprise one or more materials selected from Au, Ag, Pt, SiO ₂ , B ₂ O ₃ , P ₂ O ₅ Na ₂ O, Li ₂ O and Al ₂ O ₃ .

According to another aspect of the present invention, there is provided a carbon dioxide sensor device including: a heating pattern formed on one side of a ceramic substrate; a pair of voltage application pads connected to both ends of the heating pattern to apply a voltage; A reference electrode formed on a surface of the solid electrolyte, a reference signal pattern formed on the surface of the solid electrolyte, and a reference signal pad formed on the ceramic substrate, A sensing signal pad formed on the surface of the solid electrolyte, a sensing signal pattern formed on the surface of the solid electrolyte, a sensing signal pad formed on the ceramic substrate, a diffusion prevention layer formed on the reference electrode and the reference signal pattern, The entirety of the diffusion preventing layer, the sealing layer including the sensing signal pattern and applied to the portion excluding the sensing electrode and the reference signal pattern and the sensing signal pattern, And it includes a sensing material layer formed on the sensing electrodes.

And a pair of voltage application pads connected to both ends of the heat generation pattern to apply a voltage, wherein the heat generation pattern protection layer comprises Al ₂ O ₃ , SiO ₂ , Na ₂ O, Li ₂ O, B ₂ O ₃ , V ₂ O ₅ , MgO, ZnO, CaO, BaO, and Si ₃ N ₄ .

The heating means may partially form a solid electrolyte on the other side of the ceramic substrate on which the heating pattern is not formed.

The reference electrode, the reference signal pattern, the reference signal pad, the sensing electrode, the sensing signal pattern, and the sensing signal pad may include at least one material selected from Pt, Au, Ru, and Ag.

The diffusion barrier layer may be composed of the same material or a mixture thereof and a solid _{electrolyte, YSZ, Al 2 O 3,} ZrO 2, Y 2 O 3, SiO 2, B 2 O 3, PbO, BaO, CaO and Si ₃ N < _{4 &} gt ;.

The sealing material may include one or more materials selected from Al ₂ O ₃ , SiO ₂ , B ₂ O ₃ , PbO, BaO, CaO, and Si ₃ N ₄ .

The sensing electrode may further include a mixed layer including a noble metal and a carbonate and a porous protective layer to surround the mixed layer. The porous protective layer may include Au, Ag, Pt, SiO ₂ , B ₂ O ₃ , P ₂ O ₅ Na ₂ O, Li ₂ O, and Al ₂ O ₃ .

According to the present invention, by using the heating means printed on one side of the solid electrolyte with a thick film, it is possible to achieve low power consumption while maintaining the same driving temperature in comparison with the CO ₂ sensor using the conventional pellet type electrolyte sintered body And the temperature gradient of the entire sensor due to the heat released to the heating means at the initial stage of operation can reach the thermal equilibrium state faster than the conventional bulk type CO ₂ sensor, so that the initial operation time can be shortened.

In addition, since the entire manufacturing process is unified by the thick film process, it is easy to manufacture a standardized sensor, thereby ensuring the reproducibility of the sensor, simplifying the process and facilitating the mass production, thereby improving the productivity.

In addition, by using the heating means having the heating pattern protection layer for protecting the heating pattern, it is possible to prevent the shape of the heating pattern from changing due to the high temperature driving, to minimize the influence from the external environment, The concentration of carbon dioxide can be measured.

In addition, since the heater voltage pads and the sensor output signal pads can be applied directly to the slot type package, the durability that can secure the signal stability even in the vibration and harsh environments can be obtained by removing the durable and unreliable wire bonding method package There is an excellent advantage.

1 is a cross-sectional view of a conventional carbon dioxide sensor device.
2 is a cross-sectional view of a carbon dioxide sensor device according to an embodiment of the present invention.
3 is a schematic view showing a power supply and an electromotive force measurement structure of the carbon dioxide sensor device of FIG.
Fig. 4 is a bottom view of the carbon dioxide sensor device of Fig. 2;
Figures 5 and 6 are top views of the carbon dioxide sensor device of Figure 2;
7 is a cross-sectional view of a carbon dioxide sensor device according to another embodiment of the present invention.
FIG. 8 is a graph comparing initial operating times of the carbon dioxide sensor device of FIG. 1 and the carbon dioxide sensor device of FIG. 2;
FIG. 9 is a graph comparing the applied voltage and power consumption of the carbon dioxide sensor device of FIG. 1 and the carbon dioxide sensor device of FIG. 2 according to driving temperature.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

The terminology used herein is for the purpose of illustrating embodiments and is not intended to be limiting of the present invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. The terms " comprises "and / or" comprising "used in the specification do not exclude the presence or addition of one or more other elements in addition to the stated element.

Hereinafter, a configuration of a carbon dioxide sensor device according to an embodiment of the present invention will be described with reference to the drawings.

2, the carbon dioxide sensor device 1 according to the present embodiment includes a substrate 10, a heating pattern 21 formed on one surface of the substrate 10, a solid electrolyte 22 formed on the other surface of the substrate 10, And a passivation layer 37 laminated on the electrode patterns 32 and 34. The electrode patterns 32 and 34 are formed on one surface of the solid high-quality layer 31, 34 includes a first electrode pattern 32 and a second electrode pattern 34 spaced from each other and the passivation layer 37 includes an opening portion through which the second electrode pattern 34 is exposed to the outside, A sensing material layer 38 is stacked on the upper surface of the substrate 10, and the heating pattern 21 receives electric power from the outside to heat the substrate 10. And a diffusion barrier layer 36 formed on the first electrode pattern 32 to separate the first electrode pattern 32 and the passivation layer 37 from each other.

The substrate 10 has a heat generating pattern 21 on one side and a solid electrolyte layer 31 on the other side. There is no limitation to the material of the substrate 10, but the material may be formed of ceramics or the like so that heat generated from the heat generating pattern 21 provided on one side can be quickly and efficiently transferred to the solid electrolyte layer 31 on the other side.

The heating pattern 21 is formed on the substrate 10 so as to heat the entire area. The heating pattern 21 is formed by a method such as screen printing, spraying, doctor blade, spin coating, stencil printing or the like by using a paste containing platinum And the material and the forming method to be used can be further variously used.

The heat generating pattern protection layer 22 may be formed on the heat generating pattern 21 and the heat generating pattern protecting layer 22 may include a heat generating pattern 21 on one side where the heat generating pattern 21 of the substrate 10 is formed, Thus, it is possible to suppress the resistance change or the shape change of the heat generating pattern 21 according to the external environment. In addition, the heating pattern 21 can maintain a constant high temperature drive temperature required for carbon dioxide concentration measurement regardless of the external environment.

The heat generating pattern protective layer 22 is formed of a material selected from Al ₂ O ₃ , SiO ₂ , Na ₂ O, Li ₂ O, B ₂ O ₃ , V ₂ O ₅ , MgO, ZnO, CaO, BaO, and Si ₃ N ₄ And may include one or more.

The heat generating pattern protective layer 22 can be formed in the form of a paste and can be formed by a method such as screen printing, spraying, doctor blade, spin coating, stencil printing, and the like. Lt; / RTI >

The carbon dioxide sensor device 1 according to the present embodiment is configured such that the electromotive force measured by the sensing electrode and the reference electrode provided on one or both surfaces of the solid electrolyte layer 31 in the galvanic cell structure is determined by the Nernst equation, And it is based on the principle that it is changed according to the concentration of.

At this time, the solid electrolyte layer 31 to an alkali ion conductor, such as lithium, sodium, potassium, and more particularly beta alumina (β-alumina: Na ₂ O and χ Al ₂ O _3), tank top cone (NASICON: Na _{1 + y Zr 2 Si y P 3} - y O 12), Na 2 CO 3, Li 2 CO 3, K 2 alkali metal carbonate, such as CO _3, Li ₃ PO ₄ or LIPON (Lithium Phosphorous OxyNitride), LISICON (Li 1 _{+ y} Zr ₂ Si _y P _{3 - y} O ₁₂ ), or a mixture thereof (X and Y are independently constants of 1 to 11 and 1 to 3, respectively). The solid electrolyte layer 31 may be formed in the form of a paste on the other side of the substrate 10 and may be formed as a thick film by a method such as tape casting, screen printing, spraying, doctor blade, spin coating, stencil printing, And the forming method may be further variously used.

The first electrode pattern 32 and the second electrode pattern 34 may be formed on one side or both sides of the solid electrolyte layer 31. The first electrode pattern 32 may correspond to the reference electrode and the second electrode pattern 34 may correspond to the sensing electrode. And electrode pads 33 and 35 having one ends of the electrode patterns 32 and 34 extended to be exposed to the outside of the passivation layer 37. [ One surface of the electrode pads 33 and 35 can be in contact with the substrate 10.

The first electrode pattern 32 is formed on the surface of the solid electrolyte layer 31. The first electrode pad 33 is formed on the substrate 10 and includes at least one material selected from Pt, Au, Ru, and Ag . The first electrode pattern 32 and / or the first electrode pad 33 may be formed in the form of a paste using a method such as screen printing, spraying, doctor blade, spin coating, stencil printing or the like, The material and the forming method can be used in various other ways.

The second electrode pattern 34 is formed on the surface of the solid electrolyte layer 31 like the first electrode pattern 32. The second electrode pad 35 is formed on the substrate 10 and is made of Pt, And Ag. ≪ / RTI > The second electrode pattern 34 and / or the second electrode pad 35 may be formed in the form of a paste using a method such as screen printing, spraying, doctor blade, spin coating, stencil printing or the like. The material and the forming method can be used in various other ways.

The diffusion barrier layer 36 may be formed on the first electrode pattern 32 to separate the first electrode pattern 32 from the passivation layer 37. That is, the diffusion preventing layer 36 is required to suppress the passivation layer 37 from reacting with the first electrode pattern 32 to cause a signal change, and may be formed only on the first electrode pattern 32, The barrier layer 36 is formed of the same material as the solid electrolyte layer 31 or one of YSZ, Al ₂ O ₃ , ZrO ₂ , Y ₂ O ₃ , SiO ₂ , B ₂ O ₃ , PbO, BaO, CaO, and Si ₃ N ₄ Or more. The diffusion preventing layer 36 may be formed in the form of a paste using a method such as screen printing, spraying, doctor blade, spin coating, stencil printing, etc., and the material and the forming method used may be variously used .

A passivation layer 37 is formed on the front surface of the solid electrolyte layer 31 on the substrate 10 to seal the solid electrolyte layer 31 and the first electrode pattern 32, ), The second electrode pattern 34, and the second electrode pad 35 are excluded from the sealing range so as to be exposed to the outside. That is, the passivation layer 37 may form an opening to expose the second electrode pattern 34 to the outside, and the passivation layer 37 may be formed in a region where the first and second electrode pads 33 and 35 are formed .

The passivation layer 37 may comprise one or more materials selected from Al ₂ O ₃ , SiO ₂ , B ₂ O ₃ , PbO, BaO, CaO, and Si ₃ N ₄ . The passivation layer 37 may be formed in the form of a paste using a method such as screen printing, spraying, doctor blade, spin coating, stencil printing, or the like, and the material and the forming method used may be variously used .

The sensing material layer 38 may be formed on top of the second electrode pattern 34 and the sensing material layer 38 may comprise a noble metal or carbonate. The sensing material layer 38 may be a mixture of noble metal and carbonate, and the mixed layer of noble metal and carbonate may be Na ₂ CO ₃ , BaCO ₃ , Li ₂ CO ₃ , SrCO ₃ , CaCO ₃ , Cs ₂ CO ₃ , MnCO _{3 , MgCO 3, K 2 CO 3} , Rb 2 CO 3, may include one or more noble metals selected from one or more carbonates and, Pt, Au, and Ag is selected from CuCO _3.

In some other embodiments, the sensing material layer 38 may contain at least one carbonate selected from BaCO ₃ , Na ₂ CO ₃ , Li ₂ CO ₃ , CaCO ₃ , and at least one noble metal selected from Pt and Au .

The method of manufacturing the sensing material layer 38 may be a thick film formation using a paste printing method such as screen printing, spraying, doctor blade, spin coating, stencil printing, etc., Can be used.

The porous protective layer 39 may be deposited on top of the sensing material layer 38. One or more substances selected porous protective layer (39) comprises a noble metal or an oxide, in the _{Au, Ag, Pt, SiO 2} , B 2 O 3, P 2 O 5 Na 2 O, Li 2 O and Al ₂ O ₃ . ≪ / RTI > The porous protective layer 39 may be formed in the form of a paste by a method such as screen printing, spraying, doctor blade, spin coating, stencil printing, etc., Can be used.

3 and 4, the heating pattern 21 formed on one surface of the substrate 10 may be connected to the power supply unit 40 to receive a predetermined voltage and / or current. The heating pattern 21 may be disposed inside the heating pattern protection layer 22 and the heating pattern pad 21_1 may be partially exposed to the outside of the heating pattern protection layer 22. [ The power supply unit 40 may be connected to the heating pattern pad unit 21_1 to supply power.

5 and 6, the electrode patterns 32 and 34 are electrically connected to the terminal portions 32a and 34a, the connecting portions 32b and 34b extending from the terminal portions 32a and 34a and the electrode pads 32b and 34b formed at the ends of the connecting portions 32b and 34b, 33, and 35 may be formed. The electrode patterns 32 and 34 may be formed on the solid electrolyte layer 31 and the diffusion barrier layer 36 may be formed on the first electrode pattern 32. [

When the passivation layer 37 is laminated, at least a part of the second electrode pattern 34 corresponding to the sensing electrode, only the first and second electrode pads 33 and 35 are exposed and the remaining portion is sealed. A sensing material layer 38 may be deposited on the exposed second electrode pattern 34 and a porous protective layer 39 may be further deposited on the sensing material layer 38.

Referring to FIG. 7, a cross-sectional view of a carbon dioxide sensor device according to another embodiment of the present invention is disclosed. The carbon dioxide sensor device according to the present embodiment is the same as the previous embodiment except that the first electrode pattern 32 is formed under the solid electrolyte layer 31 and the structure of the diffusion prevention layer 36 is omitted Do. That is, since the first electrode pattern 32 is separated from the passivation layer 37 by the solid electrolyte layer 31, the structure of the diffusion preventing layer 36 can be omitted.

FIG. 8 is a graph comparing the initial operating time of the carbon dioxide sensor device of FIG. 1 with the initial operating time of the carbon dioxide sensor device of FIG. 2, Power comparison graph.

Referring to FIG. 8, it can be seen that the initial operation time of the carbon dioxide sensor apparatus according to an embodiment of the present invention is significantly reduced as compared with the conventional carbon dioxide sensor apparatus. The carbon dioxide concentration is lowered to 1000 ppm or less, and the initial operation time is longer than 40 minutes for the conventional product, whereas the carbon dioxide sensor device according to the embodiment of the present invention takes about 5 minutes or more.

Referring to FIG. 9, in the case of a conventional sensor device, a high voltage (4.2 V based on 400 ° C) must be applied in order to reach a specific driving temperature, whereas in the case of the sensor device according to the present embodiment, 3.7V based on 400 ° C), the driving temperature can be reached, so that it can be driven at a low power.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, You will understand. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

10: substrate
21: Heating pattern
22: Heating pattern protective layer
31: solid electrolyte layer
32: first electrode pattern
33: first electrode pad
34: second electrode pattern
35: second electrode pad
36: diffusion prevention layer
37: Passivation layer
38: sensing material layer
39: porous protective layer

Claims (9)

Board;
A heating pattern formed on one surface of the substrate;
A solid electrolyte layer formed on the other surface of the substrate;
An electrode pattern formed on one surface of the solid body overall layer; And
And a passivation layer laminated on the electrode pattern,
Wherein the electrode pattern includes a first electrode pattern and a second electrode pattern which are spaced apart from each other,
Wherein the passivation layer includes an opening portion through which the second electrode pattern is exposed to the outside,
A sensing material layer is laminated on the opening,
Wherein the heating pattern heats the substrate by receiving electric power from the outside. The method according to claim 1,
And a diffusion preventing layer formed on the first electrode pattern to separate the first electrode pattern and the passivation layer. The method according to claim 1,
And an electrode pad having one end of the electrode pattern extended to the outside of the passivation layer,
And one surface of the electrode pad is in contact with the substrate. The method according to claim 1,
Wherein the solid electrolyte layer is formed in a thick film form on the substrate. The method according to claim 1,
Wherein the sensing material layer comprises a noble metal or carbonate. The method according to claim 1,
And a porous protective layer laminated on top of the sensing material layer. The method according to claim 6,
Wherein the porous protective layer comprises at least one material selected from Au, Ag, Pt, SiO ₂ , B ₂ O ₃ , P ₂ O ₅ Na ₂ O, Li ₂ O and Al ₂ O ₃ . The method according to claim 1,
And a heating pattern protection layer formed on the heating pattern and covering the heating pattern. The method according to claim 1,
Wherein the first electrode pattern is formed under the solid electrolyte layer, and the first electrode pattern is spaced apart from the passivation layer.

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