Method for making soot sensor
View Patent ↗An ablating device is used to form a pattern into a sensing element pad of a soot sensor, with the pattern establishing two finger paths without electrical connection between them. The pattern can be formed through a protective layer on the sensing element pad before the sensing element pad is fired.
1. A method for making a soot sensor comprising:
establishing at least one electrically conductive sensing element pad on a non conductive substrate;
disposing a protective layer on the element pad; and
using an ablating device to cut a pattern into the protective layer and pad so as to establish two separate inter-digitized fingers paths in the pad without electrical connection between the finger paths and so as to leave a portion of the perimeter of the inter-digitized finger paths exposable to soot.
2. The method of claim 1 , wherein a sensing end portion of the pad is continuously solid, and the method comprises:
forming a pattern in the sensing end portion of the pad and no other region of the pad using an ablating device to establish the finger paths.
3. The method of claim 1 , wherein the pad includes a conductive ink and the act of forming is undertaken prior to firing the ink.
4. The method of claim 1 , wherein the pad includes a conductive ink and the act of using an ablating device is undertaken after firing the ink.
5. The method of claim 1 , comprising laminating the substrate to a heater prior to the act of using an ablating device.
6. The method of claim 5 , wherein plural soot sensors are formed as a single assembly and then separated from each other.
7. The method of claim 1 , comprising electrically connecting the pad to a computer and using the pad to generate signals representative of a soot.