PARTICULATE MATTER DETECTION ELEMENT AND METHOD OF MANUFACTURING SAME

• US 20130283886A1
• Filed: 03/18/2013
• Published: 10/31/2013
• Est. Priority Date: 04/27/2012
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: TERANISHI, Shinya, Kihara, Noriaki, Kimata, Tekehito
• Granted Patent: US 9,528,971 B2
• Time in Patent Office: Days
• US Class Current: 73/23.31
• CPC Class Codes: G01N 15/0606 by collecting particles on a support
• CPC Class Codes: G01N 15/0656 using electric, e.g. electrostatic methods or magnetic methods by investigating individual particles G01N15/1031, G01N15/12
• CPC Class Codes: G01N 2015/0046 in gas, e.g. smoke
• CPC Class Codes: G01N 33/0047 for organic compounds

Abstract

The particulate matter detection element is constituted of a laminated body including first and second electrode layers each having a plate-like shape and a thickness between 50 μm and 500 μm laminated on each other through an intermediate insulating layer having a plate-like shape and a thickness between 3 μm and 20 μm. A cross-sectional surface of the laminated body in the lamination direction is used as a detection surface of the particulate matter detection element.

Claims

1. A particulate matter detection element for detecting particulate matter contained in a measured gas comprising:

at least one pair of detection electrodes disposed opposite to each other on a detection surface of the particulate matter detection element; and

an output means for outputting a signal representing one of a resistance, a capacitance and a impedance between the pair of the detection elements as an electrical characteristic varying depending on an amount of particulate matter present between the pair of the detection electrodes;

wherein

the pair of the detection electrodes is constituted as an electrode layer laminated body in which first and second electrode layers each having a plate-like shape and a thickness in a range between 50 μ

m and 500 μ

m are laminated on each other through an intermediate insulating layer having a plate-like shape and a thickness in a range between 3 μ

m and 20 μ

m, and

a cross-sectional surface in a lamination direction of the electrode layer laminated body exposed to outside is used as the detection surface of the particulate matter detection element.

2. The particulate matter detection element according to claim 1, further comprising a first end-portion insulating layer covering one end of the first electrode layer on a first side of the electrode laminated body, and a second end-portion insulating layer covering one end of the second electrode layer on a second side opposite to the first side of the electrode laminated body, so that the first electrode layer is electrically connected externally and the second electrode layer is insulated from outside on the second side, and the second electrode layer is electrically connected to outside and the first electrode layer is insulated from outside on the first side.

3. The particulate matter detection element according to claim 2, further comprising a first common electrode connected with the first electrode layer on the second side of the electrode laminated body and a second common electrode connected with the second electrode layer on the first side of the electrode laminated body.

4. The particulate matter detection element according to claim 3, further comprising an insulating substrate of a plate-like shape,

the output means including:

first and second land portions formed on the insulating substrate and holding the electrode laminated body, the first land portion being connected to the first electrode layer, the second land portion being connected to the second electrode layer;

first and second lead portions connected to the first land portion and the second land portion, respectively; and

first and second terminal portions connected to the first lead portion and the second lead portion, respectively.

5. The particulate matter detection element according to claim 4, wherein a protection layer having an opening and made of an insulating material is formed on a surface of the insulating substrate so as to cover the detection surface such that only a portion of the detection surface in which the first and second electrode layers and the intermediate insulating layer extend in parallel to one another is exposed from the opening of the protection layer.

6. The particulate matter detection element according to claim 4, wherein an insulative protection layer having first and second openings is formed on a surface of the insulating substrate such that only a portion in which the first electrode layer and the first land portion are connected to each other is exposed from the first opening, and only a portion in which the second electrode layer and the second land portion are connected to each other is exposed from the second opening.

7. The particulate matter detection element according to claim 1, wherein the first and second electrode layers are made of a perovskite-type conductive oxide material having an electrical conductivity of higher than 10⁻

2 S/cm selected from LNF (LaNi_0.6Fe_0.4O₃), LSN (La_1.2Sr_0.8NiO₄), LSM (La_1-XSr_XMnO_3-δ

), LSC (La_1-XSr_XCoO_3-δ

), LCC (La_1-XCa_XCrO_3-δ

), and LSCN (La_0.85Sr_0.15Cr_1-XNiXO_3-δ

) (0.1≦

X≦

0.7).

8. The particulate matter detection element according to claim 1, wherein the intermediate insulating layer is made of an insulating oxide material having an electrical conductivity of lower than 10⁻

5 S/cm selected from a partially stabilized zirconia typified by 8YSZ((ZrO₂)_0.82(Y₂O₃)_0.08), MgO and Al₂O₃.

14. A particulate matter detection sensor comprising:

the particulate material detection element as recited in claim 1; and

an electrical characteristic detection means for determining an amount of particulate matter collected between the pair of the detection electrodes based on the signal outputted from the output means.

9. A method of manufacturing a particulate matter detection element for detecting particulate matter contained in a measured gas, the particulate matter detection element including at least one pair of detection electrodes disposed opposite to each other on a detection surface of the particulate matter detection element, and an output means for outputting a signal representing one of a resistance, a capacitance and a impedance between the pair of the detection elements as an electrical characteristic varying depending on an amount of the particulate matter present between the pair of the detection electrodes, the method comprising:

an electrode layer forming step of forming a first green sheet for a first electrode layer and a second green sheet for a second electrode layer each having a plate-like shape and a thickness in a range between 50 μ

m and 500 μ

m using a perovskite-type conductive oxide metal selected from LNF (LaNi_0.6Fe_0.4O₃), LSN (La_1.2Sr_0.8NiO₄), LSM (La_1-XSr_XMnO_3-δ

), LSC (La_1-XSr_XCoO_3-δ

), LCC (La_1-XCa_XCrO_3-δ

), and LSCN (La_0.85Sr_0.15Cr_1-XNiXO_3-δ

) (0.1≦

X≦

0.7);

an insulating layer forming step of forming a third green sheet for an intermediate insulating layer having a plate-like shape and a thickness in a range between 3 μ

m and 20 μ

m using an insulating oxide material selected from a partially stabilized zirconia typified by 8YSZ((ZrO₂)_0.82(Y₂O₃)_0.08), MgO and Al₂O₃; and

a laminated body forming step of forming the electrode layer laminated body by laminating the first to third green sheets.

10. The method of manufacturing a particulate matter detection element according to claim 9, wherein

the particulate matter detection element further includes a first end-portion insulating layer covering one end of the first electrode layer on a first side of the electrode laminated body, and a second end-portion insulating layer covering one end of the second electrode layer on a second side opposite to the first side of the electrode laminated body, so that the first electrode layer is electrically connected to outside and the second electrode layer is insulated from outside on the second side, and the second electrode layer is electrically connected to outside and the first electrode layer is insulated from outside on the first side, and

the method further comprises an end-portion forming step of forming a fourth green sheet for the first and second end-portion insulating layers using the insulating oxide material, the fourth green sheet having a plate-like shape and a thickness substantially the same as the first and second green sheets, and an insulating layer embedding step of cutting the fourth green sheet into a predetermined shape, and embedding the cut fourth green sheet into each of the first and second green sheets.

11. The method of manufacturing a particulate matter detection element according to claim 10, wherein

the particulate matter detection element further includes a first common electrode connected with the first electrode layer on the second side of the electrode laminated body and a second common electrode connected with the second electrode layer on the first side of the electrode laminated body, and

the method further comprises a common electrode layer sheet forming step of forming a fifth green sheet for the first and second common electrodes, the fifth green sheet having a plate-like shape and a thickness substantially the same as the intermediate insulating layer, and a common layer embedding step of cutting the fifth green sheet into a predetermined shape, and embedding the cut fifth green sheet into the third green sheet.

12. A method of manufacturing a particulate matter detection element for detecting particulate matter contained in a measured gas, the particulate matter detection element including at least one pair of detection electrodes disposed opposite to each other, and an output means for outputting a signal representing one of a resistance, a capacitance and a impedance between the pair of the detection elements as an electrical characteristic varying depending on an amount of particulate matter present between the pair of the detection electrodes, the method comprising:

an electrode layer forming step of forming a first green sheet for a first electrode layer and a second green sheet for a second electrode layer each having a plate-like shape and a thickness in a range between 50 μ

m and 500 μ

m using a perovskite-type conductive oxide material selected from LNF (LaNi_0.6Fe_0.4O₃), LSN (La_1.2Sr_0.8NiO₄), LSM (La_1-XSr_XMnO_3-δ

), LSC (La_1-XSr_XCoO_3-δ

), LCC (La_1-XCa_XCrO_3-δ

), and LSCN (La_0.85Sr_0.15Cr_1-XNiXO_3-δ

) (0.1≦

X≦

0.7);

an insulating layer forming step of print-forming an intermediate insulating layer film having a plate-like shape and a thickness in a range between 3 μ

m and 20 μ

m on a surface of each of the first and second green sheets using an insulating oxide material selected from a partially stabilized zirconia typified by 8YSZ((ZrO₂)_0.82(Y₂O₃)_0.08), MgO and Al₂O₃; and

a laminated body forming step of forming the electrode layer laminated body by laminating the first and second green sheets formed with the intermediate insulating layer film.

13. The method of manufacturing a particulate matter detection element according to claim 12, wherein the particulate matter detection element further includes a first common electrode connected with the first electrode layer on the second side of the electrode laminated body and a second common electrode connected with the second electrode layer on the first side of the electrode laminated body, and

the method further comprises a common electrode forming step of forming the first and second common electrodes by a thick film printing method or a green sheet applying method using the conductive oxide material.