Sensor for detecting electrically conductive and/or polarizable particles, sensor system, method for operating a sensor, method for producing a sensor of this type and use of a sensor of this type

Abstract

A sensor for detecting electrically conductive and/or polarizable particles, in particular for detecting soot particles, includes a substrate and at least two electrode layers, a first electrode layer and at least one second electrode layer, which is arranged between the substrate and the first electrode layer. At least one insulation layer is formed between the first electrode layer and the at least one second electrode layer and at least one opening is formed in both the first electrode layer and the at least one insulation layer. At least some sections of the opening in the first electrode layer and of the opening in the insulation layer are arranged one above the other, such that at least one passage is formed to the second electrode layer.

What is claimed is: 
     
         1 .- 43 . (canceled) 
     
     
         44 . A sensor for detecting soot particles, the soot particles being electrically conductive or polarizable, the sensor comprising:
 a substrate,   a first electrode layer and a second electrode layer, the second electrode layer arranged between the substrate and the first electrode layer;   a first insulation layer disposed between the first electrode layer and the second electrode layer; and   a first opening disposed in the first electrode layer and a second opening disposed in the first insulation layer;   wherein the first opening and the second opening are aligned to form a first passage to the second electrode layer.   
     
     
         45 . The sensor as claimed in  claim 44 , wherein the first passage is in a form of an elongate depression. 
     
     
         46 . The sensor as claimed in  claim 44 , wherein the first opening is formed at a distance from a peripheral region of the first electrode layer and the second opening is formed at a distance from a peripheral region of the first insulation layer. 
     
     
         47 . The sensor as claimed in  claim 44 , wherein the first electrode layer or the second electrode layer comprises a metal, a metal alloy, a high-temperature-resistant metal, a high-temperature-resistant alloy, a platinum metal, or an alloy of a metal of the platinum metals. 
     
     
         48 . The sensor as claimed in  claim 44 ,
 wherein the first electrode layer comprises a first material selected from the group of a metal, a metal alloy, a high-temperature-resistant metal, a high-temperature-resistant alloy, a platinum metal, or an alloy of platinum metals,   wherein the second electrode comprises a second material selected from the group of a metal, a metal alloy, a high-temperature-resistant metal, a high-temperature-resistant alloy, a platinum metal, or an alloy of platinum metals, and   wherein the second material has a higher etching resistance than the first material.   
     
     
         49 . The sensor as claimed in  claim 44 , further comprising a covering layer disposed on a side of the first electrode layer, the side of the first electrode layer facing away from the first insulation layer, the covering layer comprising ceramic, a glass, a metal oxide, or a combination thereof. 
     
     
         50 . The sensor as claimed in  claim 44 ,
 further comprising a second insulation layer and a third electrode layer, the second insulation layer disposed between the first electrode layer and the third electrode layer.   
     
     
         51 . The sensor as claimed in  claim 44 ,
 further comprising a plurality of holes in each of the first electrode layer and the first insulation layer being aligned to form a plurality of passages, each passage of the plurality of passages comprising an elongate depression, the plurality of passages being arranged in a grid.   
     
     
         52 . The sensor as claimed in  claim 44 , wherein the first passage comprises a meandering shape or a spiral shape. 
     
     
         53 . The sensor as claimed in  claim 44 , wherein the elongate depression comprises a V-shape, a U-shape, or a half-round cross sectional shape. 
     
     
         54 . The sensor as claimed in  claim 44 , wherein the second hole forms an undercut or a clearance in the first passage. 
     
     
         55 . The sensor as claimed in  claim 44 ,
 further comprising a third opening disposed in the first electrode layer and a fourth opening disposed in the insulation layer,   wherein the third opening and the fourth opening are arranged at least in certain portions one over the other to form a second passage to the second electrode layer,   wherein the first passage is a first blind hole having a first cross-sectional area,   wherein the second passage is a second blind hole having a second cross-sectional area, and   wherein the first cross-sectional area is larger than the second cross-sectional area.   
     
     
         56 . The sensor as claimed in  claim 44 ,
 wherein the first electrode layer comprises a first electrical contact area,   wherein the second electrode layer comprises a second electrical contact area,   wherein the first electrical contact area is connected to the first electrode layer, the second electrical contact area is connected to the second electrode layer,   wherein the second electrical contact area is not overlayed by the insulation layer and the first electrode layer,   wherein the first electrical contact area is not overlayed by a covering layer, and   wherein each electrical contact area is connected to a terminal pad.   
     
     
         57 . The sensor as claimed in  claim 56 ,
 wherein the first electrode layer or the second electrode layer comprises a strip conductor loop, strip conductor loop being a heating coil, a temperature-sensitive layer, a shielding electrode, or a combination thereof,   wherein the first electrode layer or the second electrode layer comprising the strip conductor loop comprises further a third electrical contact area not overlayed by the insulation layer or an electrode layer, and   wherein the third electrical contact area is connected with the terminal pad.   
     
     
         58 . The sensor as claimed in  claim 57 , wherein the first passage does not lie over a gap between portions of the strip conductor loop and a second strip conductor loop of the second electrode layer. 
     
     
         59 . The sensor as claimed in  claim 44 , wherein the first electrode layer or the second electrode layer is at a different electrical potential than an ambient environment. 
     
     
         60 . A sensor system comprising:
 the sensor of  claim 44 , and   a controller or a control circuit, the controller or the control circuit for operating the sensor in a measuring mode, in a cleaning mode, in a monitoring mode, or a combination thereof.   
     
     
         61 . A method for controlling the sensor as claimed in  claim 44 , the method comprising the step of:
 operating the sensor in a measuring mode, in a cleaning mode, in a monitoring mode, or a combination thereof.   
     
     
         62 . A method of making a sensor for detecting soot particles, the soot particles being electrically conductive or polarizable, the sensor comprising
 a substrate;   a first electrode layer and a second electrode layer, the second electrode layer arranged between the substrate and the first electrode layer;   an insulation layer disposed between the first electrode layer and the second electrode layer;   the method comprising the steps of:   laminating the first electrode layer, the second electrode layer, and the insulation layer to form a laminate, the insulation layer being disposed between the first electrode layer and the second electrode layer,   subsequently forming a passage through the first electrode layer and the insulation layer, the passage comprising an elongate depression, and   ending the passage to have a bottom formed by a portion of the second electrode layer.   
     
     
         63 . The method as claimed in  claim 62 ,
 wherein the elongate depression is formed by etching, in plasma-ion etching, or successive etching adapted to each layer being etched,   wherein the insulation layer is etching-resistant layer, and   wherein a portion of the elongate depression in the insulation layer is formed by a conditioning process with phase conversion of the insulation layer.   
     
     
         64 . The method as claimed in  claim 62 ,
 wherein the elongate depression is formed by etching, in plasma-ion etching, or successive etching adapted to each layer being etched, and   wherein the insulation layer is etching-resistant layer, the elongate depression being formed in the insulation layer by a conditioning process with phase conversion of the insulation layer.   
     
     
         65 . The method as claimed in  claim 62 ,
 wherein the elongate depression is partially formed by laser machining, and   wherein laser machining is performed by a laser source, wavelength, a laser pulse frequency adapted individually to each of the first electrode layer, the second electrode layer, and the insulation layer.   
     
     
         66 . A method of making a sensor for detecting soot particles, the soot particles being electrically conductive or polarizable, the sensor comprising
 a substrate;   a first electrode layer and a second electrode layer, the second electrode layer arranged between the substrate and the first electrode layer;   an insulation layer disposed between the first electrode layer and the second electrode layer;   the method comprising the steps of:   laminating the first electrode layer, the second electrode layer, and the insulation layer to form a laminate, the insulation layer being disposed between the first electrode layer and the second electrode layer,   wherein the insulation layer and the first electrode layer are structured by a lift-off process, an ink-jet process, a stamping process one over the other forming a passage to the second electrode layer, the passage being in a form of an elongate depression.   
     
     
         67 . A method of using the sensor of  claim 44 , the method comprising the step of:
 directing a flow (a) of the soot particles to not impinge perpendicularly on a plane (x, y) of the first electrode layer or the second electrode layer.   
     
     
         68 . A method of using the sensor of  claim 44 , the method comprising the step of:
 detecting electrically conductive or polarizable particles, and   adjusting an angle α between a normal (z) to a plane (x, y) of the first electrode layer and a direction of a flow (a) of the particles to 1 degree or more, 10 degrees or more, or 30 degrees or more.   
     
     
         69 . A method of using the sensor of  claim 44 , the method comprising the step of:
 detecting electrically conductive or polarizable particles, and   adjusting an angle β between a direction of flow (a) of the particles and a longitudinal axis (x) of the elongate depression to between 20 and 90 degrees.