JP2009085959A - Sensor element for detecting particle in gas, and manufacturing method for sensor element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sensor for detecting a particle in an exhaust gas capable of protecting a measuring electrode and capable of precluding a function of the measuring electrode from varying. <P>SOLUTION: Protection layers 1a, 1b are formed and arranged to be congruent with upper faces of the measuring electrodes 3,4, in a sensor element having the protection layers 1a, 1b, a measuring system 2 having the first measuring electrode 3 and the second measuring electrode 4 engaged with each other comb-likely, and an insulating layer 5. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a sensor element for detecting particles in a gas, a method for manufacturing such a sensor element, and the use of such a sensor element.

  In the near future, legal regulations will be required to monitor particulate emissions of automobiles, especially during driving, after continuous operation of the engine or diesel particulate filter (DPF). In addition, to ensure high system reliability with a few regeneration cycles with high efficiency and low fuel consumption, and to be able to use inexpensive filter materials such as cordierite, for regeneration control It is necessary to estimate the amount of accumulated diesel particulate filter.

  In order to do this, a particulate sensor resistant to conductive particles can be used. At present, the following resistive particulate sensors are known. That is, a particulate sensor is known in which a measurement electrode system including two or more measurement electrodes (interdigital electrodes) engaged with each other in a comb shape is formed on an insulating layer. When a voltage is applied to these measurement electrodes, the particles adhere and short-circuit the measurement electrodes. As the particle concentration on the sensor surface increases, the resistance detected between the measurement electrodes after reaching the threshold decreases (or if the applied voltage is constant, the current detected between the measurement electrodes is reduced). To rise). Such varying resistance or current is associated with an increase in particles on the sensor surface. In order to regenerate the sensor, the sensor is combusted and cleaned with an integrated heating device. That is, the particles are removed.

  In order to protect the measurement electrode from gas corrosion and mechanical damage, a protective layer is entirely provided on the measurement electrode system or sensor surface. However, the protective layer provided over the entire surface is disadvantageous in that it changes the functionality of the measuring electrode.

  An object of the present invention is to provide a particle detection sensor in which the measurement electrode is protected and the functionality of the measurement electrode does not change.

  The object is solved by a sensor element in which the protective layer is formed and arranged congruently with the upper surface of the measuring electrode.

  The sensor element of the present invention as set forth in claim 1 has a protective layer constructed and / or arranged according to the present invention to protect the measuring electrode from gas corrosion and mechanical damage, impeding the functionality of the measuring electrode. Have the advantage that the operating principle does not change. The reason for this is that the protective layer according to the present invention is formed and arranged congruently with the upper surface of the measuring electrode, so that the upper surface of the measuring electrode is protected from corrosion and mechanical damage, and the function of the measuring electrode is It is guaranteed even if it is deposited. This is because the side surface (edge) of the measurement electrode and the space between the measurement electrodes are covered by the protective layer.

  Furthermore, the provision of a protective layer in this way improves the profile structure in the region of the measuring electrode system, which provides a flow guide that makes it easier for particles to deposit on the measuring electrode system, This realizes further utility of the present invention.

  The method according to the invention for producing a sensor according to the invention is carried out inter alia by laser structuring or physical vapor deposition ("PVD") or chemical vapor deposition ("CVD"), It has proven to be advantageous. This is because not only the manufacture of the sensor element according to the invention is guaranteed, but also the spacing between the measuring electrodes is significantly higher compared to conventional interdigital measuring electrode systems in which the spacing between measuring electrodes exceeds 70 μm. This is because a small measurement electrode system can be manufactured, and a measurement electrode system having an interval between the measurement electrodes of, for example, 20 μm to 40 μm can be manufactured. The smallest possible spacing between the measuring electrodes advantageously increases the sensitivity and measuring accuracy of the sensor element.

  Further advantages and advantageous embodiments of the subject matter of the invention are described in the description, the drawings and the claims.

  The present invention will be described in detail with reference to the drawings shown and described below. It should be noted that the drawings are used for illustration only and are not intended to limit the invention in any way.

  FIG. 1a is a schematic perspective view of a sensor element of the present invention for detecting particles in a gas. FIG. 1 a shows that the sensor element has a protective layer 1 a, 1 b, a measuring electrode system 2 and an insulating layer 5, which measuring electrode system engages one another in a comb shape. An electrode 3 and a second measurement electrode 4 are provided, and the protective layers 1a and 1b are disposed on the surfaces of the measurement electrodes 3 and 4, and the measurement electrodes 3 and 4 are disposed on the insulating layer 5. Has been. The sensor element of the present invention shown in FIG. 1a differs from known sensor elements in the following respects. That is, it has at least a first protective layer 1a and a second protective layer 1b, and the first protective layer 1a is formed and / or arranged congruently with the upper surface 6a of the first measurement electrode 3. The protective layer 1b is different in that it is formed and / or arranged congruently with the upper surface 6b of the second measuring electrode 4.

  In the present invention, the “upper surfaces” 6 a and 6 b of the measurement electrodes 3 and 4 refer to surfaces facing the surfaces 8 a and 8 b of the measurement electrodes 3 and 4 disposed on the insulating layer 5. Within the framework of the present invention, concepts such as “above”, “on the surface” and “below” are used to describe the arrangement of the components relative to one another, and the invention relates to the spatial orientation of the sensor elements or components. The sensor element or method is not limited.

  By means of the protective layers 1a, 1b respectively arranged on the upper surfaces 6a, 6b of the measuring electrodes 3, 4, the measuring electrode system 2 is advantageously operated by the action of the sensor element facing the gas. With the protective layers 1a, 1b according to the invention, the side surfaces (edges) 9a, 9b of the measuring electrodes 3, 4 and the space 10 between the measuring electrodes 3, 4 are not covered by the protective layers 1a, 1b, so that preferably the measuring electrodes The functionality of 3, 4 can be guaranteed.

  In the embodiment shown in FIG. 1 a, the sensor element has an insulating layer 5 and a carrier layer 7. Here, the carrier layer 7 is disposed below the insulating layer 5. Within the framework of the present invention, the carrier layer 7 can be formed from either an insulating material or a conductive material. Within the framework of the present invention, the insulating layer 5 can be formed and / or configured so that the insulating layer 5 functions as both the insulating layer 5 and the carrier layer 7.

  FIG. 1 b is a schematic cross-sectional view of the sensor element shown in FIG. 1 a taken along line AA ′.

  The object of the present invention is a sensor element for detecting particles in a gas, comprising a protective layer and at least one first measurement electrode and a second measurement electrode which are engaged with each other in a comb shape. An electrode system and an insulating layer, the protective layer being disposed on the measuring electrode, wherein the measuring electrode is at least one first protective layer in a sensor element disposed on the insulating layer And the second protective layer, and the first protective layer is formed and / or arranged congruently with the upper surface of the first measurement electrode, and the second protective layer is formed on the first measurement electrode. The present invention relates to a sensor element formed and / or arranged congruently with an upper surface.

  In one embodiment, the sensor element of the present invention has a carrier layer disposed below the insulating layer.

  The sensor element of the present invention can be manufactured by various methods of the present invention.

  One object of the present invention is a method for producing a sensor element of the present invention. In this manufacturing method, by a laser structuring method, a planar protective layer and a planar metal-containing layer or a substrate including a metal layer and a planar insulating layer as follows, that is, the protective layer includes the metal-containing layer. The metal-containing layer or metal layer disposed on the layer or metal layer removes material from the substrate disposed on the insulating layer, and the removal of the material results in the planar protective layer and the planar metal A measurement electrode having at least one first measurement electrode and a second measurement electrode, and at least one first protection layer and a second protection layer that are engaged with each other in a comb shape from the inclusion layer or the metal layer Forming a system, and forming and / or placing the first protective layer congruently with the top surface of the first measurement electrode when forming the measurement electrode system, and the second protective layer being the second measurement layer It is formed and / or arranged congruently with the upper surface of the electrode.

  In order to manufacture a substrate for this purpose, for example, a metal-containing layer or a metal layer is printed on the entire surface of the insulating layer, and a protective layer is printed on the metal-containing layer or the metal layer. The layers printed by lamination are sintered. The insulating layer can be printed over the entire surface in advance, i.e. before printing the metal-containing layer or the metal layer and the protective layer. In other words, when the substrate or the sensor element has a carrier layer, the insulating layer is printed on the entire surface of the carrier layer, and the metal-containing layer or the metal layer is printed on the insulating layer. A substrate can be produced by printing a protective layer on the entire surface of the layer or metal layer and sintering the layers printed on one another.

  Advantageously, the protective layer and the metal layer or metal-containing layer underneath the protective layer can be processed together in one working step by means of a laser structuring technique.

The invention further relates to a production method for producing the sensor element of the invention by means of a screen printing method by the following plurality of screen printing steps:
Printing on the insulating layer a measurement electrode system having at least one first measurement electrode and a second measurement electrode which are interengaged in a comb-like manner;
The first protective layer is formed and / or arranged congruently with the upper surface of the first measurement electrode, and the second protective layer is formed and / or arranged congruent with the upper surface of the second measurement electrode In particular, the first protective layer is printed with a particularly accurate positioning on the first measuring electrode, and the second protective layer is printed with a particularly accurate positioning on the second measuring electrode. Step.

The insulating layer can be printed over the entire surface in advance, i.e. before printing the measuring electrode system and the protective layer. In other words, if the sensor element has a carrier layer, the present invention allows the sensor element to be manufactured by a screen printing method by the following multiple screen printing steps:
Printing the insulating layer on the carrier layer, in particular over the entire surface.
Printing on the insulating layer a measurement electrode system comprising at least one first measurement electrode and a second measurement electrode which are interengaged in a comb-like manner; Here, the first measurement electrode and the second measurement electrode are made of a metal-containing material or a metal material.
The first protective layer is jointly formed and / or disposed on the upper surface of the first measurement electrode, and the second protective layer is jointly formed and / or disposed on the upper surface of the second measurement electrode. The first protective layer is particularly accurately positioned and printed on the first measuring electrode, and the second protective layer is particularly accurately positioned and printed on the second measuring electrode. .

  For example, a solid state laser or excimer laser, such as a neodymium YAG laser or diode laser or fiber laser, is suitable for use in the manufacturing method of the present invention. Suitable for the purpose is that the focal spot diameter of the laser is in the range of 1 μm to 70 μm.

  The present invention further relates to the following method for producing the sensor element of the present invention. In this manufacturing method, in particular, a microstructured mask is provided on the sintered insulating layer, the open area of the mask having at least one first measuring electrode and a second one engaging each other like a comb. In accordance with the structure of the measuring electrode system to be manufactured having a measuring electrode of the first physical vapor deposition ("PVD") or first chemical vapor deposition ("" Chemical vapor deposition ", CVD) is used to coat a metal-containing material or a metal material, while maintaining the position of the mask in a region coated with the metal-containing material or the metal material. The ceramic material is coated by “physical vapor deposition” (PVD) or second chemical vapor deposition (CVD).

  It is suitable for the purpose to coat the open area with a metal-containing material or a metal material so that a homogeneous layer is obtained on the basic surface of the open area. Here, the volume of the open area is advantageously not completely filled with a metal-containing material or a metal material. In this way, the ceramic material and thus the protective layer obtained thereby can be applied to a second physical vapor deposition (“PVD”) or a second chemical vapor deposition (“CVD”). Thus, it can be easily provided while maintaining the position of the mask.

  Even within the framework of this production method of the present invention, the insulating layer is preliminarily, i.e., optionally before sintering and before mask application and the first physical vapor deposition or the second physical vapor deposition or the first. Prior to the chemical vapor deposition or the second chemical vapor deposition, the support layer can be provided over the entire surface and in particular printed.

Within the framework of the present invention, the protective layer can be formed from a porous ceramic material or from a dense ceramic material. The protective layer in the context of the present invention, the layer thickness in the following areas 0.5μm or more ~50μm _{(d S)} can have, for example, the layer thickness that ~25μm following areas than 5 [mu] m _{(d S} And a layer thickness (d _S ) in the region of 10 μm to 20 μm. Within the framework of the invention, the protective layer or ceramic layer preferably comprises aluminum oxide, zirconium oxide and / or silicon oxide, preferably comprises aluminum oxide and / or zirconium oxide, in particular yttrium-doped zirconium oxide. including. In particular, the protective layer can be formed from aluminum oxide and / or zirconium oxide and / or silicon oxide, preferably from aluminum oxide and / or zirconium oxide, in particular from yttrium-doped zirconium oxide. Form. The ceramic material can in particular be formed from aluminum oxide and / or zirconium oxide and / or silicon oxide, preferably from aluminum oxide and / or zirconium oxide, in particular from yttrium-doped zirconium oxide. Form.

Within the framework of the present invention, the distance (d _MM ) between the first measuring electrode and the second measuring electrode can be 100 μm or less, for example 80 μm or less or 70 μm or less, in particular 40 μm or less. . For example, the distance (d _MM ) between the first measurement electrode and the second measurement electrode can be in the region of 15 μm to 50 μm, and particularly in the region of 20 μm to 40 μm. The measurement electrode and / or the metal layer or the metal-containing layer can have a thickness (d _M ) in the region of 1 μm to 30 μm, for example in the region of 5 μm to 20 μm, within the framework of the present invention. It has a thickness (d _M ), and particularly has a thickness (d _M ) in a region of 8 μm to 18 μm.

  Within the framework of the invention, the measuring electrode and / or the metal layer or metal-containing layer or metal material or metal-containing material can be, for example, platinum, copper, silver, gold, iron, cobalt, nickel, palladium, ruthenium, iridium and / or rhodium. Such as platinum or ceramic cermets, such as platinum / ceramic cermets, in particular platinum / aluminum oxide cermets. Can be included. In particular, the measuring electrode and / or the metal layer or the metal-containing layer can be formed from a metal or metal alloy such as platinum, copper, silver, gold, iron, cobalt, nickel, palladium, ruthenium, iridium and / or rhodium, for example. In particular, it can be formed from platinum or it can be formed from noble metal / ceramic cermets, for example it can be formed from platinum / ceramic cermets, in particular from platinum / aluminum oxide cermets. Said metal material or metal-containing material can be formed from metals or metal alloys such as, for example, platinum, copper, silver, gold, iron, cobalt, nickel, palladium, ruthenium, iridium and / or rhodium, especially from platinum It can be formed or can be formed from a noble metal / ceramic cermet, for example it can be formed from a platinum / ceramic cermet, in particular from a platinum / aluminum oxide cermet. Advantageously, said measuring electrode or metal-containing layer or metal layer is formed from a noble metal / ceramic cermet, for example formed from a platinum / ceramic cermet, in particular from a platinum / aluminum oxide cermet, or the metal material or The metal-containing material is formed from a noble metal / ceramic cermet, for example formed from a platinum / ceramic cermet, especially from a platinum / aluminum oxide cermet.

  The insulating layer preferably comprises aluminum oxide within the framework of the invention. For example, the insulating layer can be formed from aluminum oxide.

  Advantageously, the carrier layer comprises zirconium oxide within the framework of the invention, in particular yttrium-doped zirconium oxide and / or aluminum oxide. For example, the support layer can be formed from zirconium oxide, and in particular from yttrium-doped zirconium oxide and / or aluminum oxide.

  The invention also uses the sensor element of the invention for exhaust gas inspection in factory equipment, or for air quality monitoring in a measuring device, or in a soot particle sensor, in particular for “on” of an internal combustion engine. Used in soot particle sensors for “board diagnostics” (OBD) and / or operation monitoring, or used in combustion equipment, for example in oil heaters and / or ovens, and / or in the function of particulate filters It also relates to a method used for monitoring and / or monitoring particulate filter deposition and / or chemical manufacturing processes and / or exhaust equipment and / or exhaust aftertreatment equipment. The internal combustion engine is, for example, a diesel engine, and the particulate filter is, for example, a diesel particulate filter (DPF).

1 is a schematic perspective view of a sensor element according to the present invention. FIG. 1 b is a schematic cross-sectional view of the sensor element shown in FIG. 1 a taken along line AA ′.

Explanation of symbols

1a, 1b Protective layer 2 Measuring electrode system 3, 4 Measuring electrode 5 Insulating layer 7 Carrier layer

Claims (14)

A sensor element for detecting particles in exhaust gas,
A measuring electrode system (2) having a protective layer (1a; 1b), at least one first measuring electrode (3) and a second measuring electrode (4) which are interengaged in a comb-like manner, and an insulating layer ( 5)
In the sensor element of the type in which the protective layer (1a; 1b) is disposed on the measurement electrode (3, 4) and the measurement electrode (3,4) is disposed on the insulating layer (5). ,
Having at least one first protective layer (1a) and second protective layer (1b);
The first protective layer (1a) is jointly formed and / or arranged on the upper surface (6a) of the first measurement electrode (3), and the second protective layer (1b) is the second measurement electrode. Formed and / or arranged jointly on the upper surface (6b) of (4),
The upper surfaces (6a, 6b) of the measurement electrodes (3, 4) are surfaces facing the surfaces (8a, 8b) of the measurement electrodes (3, 4) disposed on the insulating layer (5). A sensor element.   Sensor element according to claim 1, comprising a carrier layer (7), the carrier layer (7) being arranged below the insulating layer (5). In the manufacturing method of the sensor element according to claim 1 or 2,
By laser structuring technique,
A planar protective layer; a planar metal-containing layer or metal layer; and a planar insulating layer comprising: a protective layer disposed on the metal-containing layer or metal layer; The metal-containing layer or metal layer removes material from the substrate disposed on the insulating layer, and by removing the material, the planar protective layer and the planar metal-containing layer or metal layer are removed. , At least one first measurement electrode (3) and second measurement electrode (4), at least one first protective layer (1a) and second protective layer (1b) which engage with each other in a comb shape. And forming the measurement electrode system (2), the first protective layer (1a) is congruent with the upper surface (6a) of the first measurement electrode (3). Formed and / or disposed on the upper surface of the second measuring electrode (4). Manufacturing method characterized by b) to form and / or arranged in congruence. -Print a metal-containing layer or metal layer entirely on the surface of the insulating layer,
-Print the entire surface of the protective layer on the metal-containing layer or metal layer,
4. The manufacturing method according to claim 3, wherein the substrate is manufactured by sintering the insulating layer and the metal-containing layer or the metal layer and the protective layer which are printed to overlap each other. By screen printing method,
A screen for printing on the insulating layer (5) a measuring electrode system (2) having at least one first measuring electrode (3) and a second measuring electrode (4) which are interengaged in a comb-like manner; A printing step;
The first protective layer (1a) is formed and / or arranged congruently with the upper surface (6a) of the first measurement electrode (3), and the second protective layer (1b) is the second measurement layer The first protective layer (1a) is positioned particularly precisely on the first measuring electrode (3) so that it is formed and / or arranged congruently with the upper surface (6b) of the electrode (4). 5. The method according to claim 3, wherein printing is performed, and a screen printing step is performed in which the second protective layer (1 b) is particularly accurately positioned and printed on the second measuring electrode (4). In particular, a microstructured mask is provided on the sintered insulating layer (5), the open area of the mask comprising at least one first measuring electrode (3) and a second interdigitated intercombination. Corresponding to the structure of the measuring electrode system (2) to be manufactured with two measuring electrodes (4),
The open area is coated with a metal-containing material or a metal material by a first physical vapor deposition (“PVD”) or a first chemical vapor deposition (“CVD”). ,
A second physical vapor deposition (PVD) or second chemical vapor deposition (PVD) while maintaining the position of the mask in the metal-containing or metal-coated region. 6. The method according to claim 3, wherein the ceramic material is coated by "chemical vapor deposition" (CVD).   The method according to any one of claims 5 to 7, wherein the insulating layer (5) is printed in advance on the carrier layer (7) in advance.   The sensor element according to claim 1 or 2, or the manufacturing method according to any one of claims 3 to 7, wherein the protective layer (1a, 1b) is formed of a porous or high-density ceramic material. The protective layer (1a, 1b) may have a layer thickness (d _S ) in a region of 0.5 μm to 50 μm, for example, a layer thickness (d _S in a region of 5 μm to 25 μm). The sensor element according to claim 1, 2 or 8, or any one of claims 3 to 8, in particular having a layer thickness (d _S ) in the region from 10 μm to 20 μm. Production method.   Said protective layer (1a, 1b) or said ceramic material comprises aluminum oxide and / or zirconium oxide and / or silicon oxide, preferably comprising aluminum oxide and / or zirconium oxide, in particular yttrium-doped zirconium oxide. 10. The sensor element according to claim 1 or 2 or 8 or 9, or the production method according to any one of claims 3 to 9. 3. The distance (d _MM ) between the first measuring electrode (3) and the second measuring electrode (4) is not more than 100 μm, for example not more than 80 μm, in particular not more than 40 μm. Or the sensor element of any one of 8-10, or the manufacturing method of any one of Claim 3-10.   The measurement electrode (3, 4) or the metal layer or the metal-containing layer or the metal material or the metal-containing material is, for example, platinum, copper, silver, gold, iron, cobalt, nickel, palladium, ruthenium, iridium and / or Or a metal or metal alloy such as rhodium, in particular platinum, or a noble metal / ceramic cermet, for example a platinum / ceramic cermet, in particular platinum / aluminum oxide. The sensor element according to any one of claims 1 or 2, or 8 to 11, or a production method according to any one of claims 3 to 11, comprising cermet.   The sensor element according to claim 1, 2 or 8 to 12, or the manufacturing method according to any one of claims 3 to 12, wherein the insulating layer (5) contains aluminum oxide.   Sensor element or claim 3 according to claim 1 or 2 or 8 to 13, wherein the carrier layer (7) comprises zirconium oxide and / or aluminum oxide, in particular comprising yttrium-doped zirconium oxide. 14. The manufacturing method according to any one of up to 13.

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