ELECTRODE TESTING APPARATUS

• US 20130320994A1
• Filed: 05/30/2012
• Published: 12/05/2013
• Est. Priority Date: 05/30/2012
• Status: Abandoned Application

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: BRITTAIN, Kenneth G., Herbert, Sammuel D., Diamond, Neil F.
• Application Number:
  US13/483,746
• Publication Number:
  US 20130320994A1
• Time in Patent Office: Days
• US Class Current: 324/537
• CPC Class Codes: G01R 27/14 Measuring resistance by measuring current or voltage obtained from a reference source G01R27/16, G01R27/20, G01R27/22 take precedence
• CPC Class Codes: G01R 31/2813 Checking the presence, location, orientation or value, e.g. resistance, of components or conductors orientation of the DUT with respect to the test fixture G01R1/06705, G01R31/281
• CPC Class Codes: G01R 31/2829 Testing of circuits in sensor or actuator systems testing of apparatus for measuring electric or magnetic variables G01R35/00; testing of indicating or recording apparatus G01D; in airbag systems B60R21/0173; checking gas analysers G01N33/007; monitoring or fail-safe circuits for electromagnets H01F7/1844
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes

Abstract

An apparatus to infer the resistivity of an electrode by stimulating the electrode with a capacitively coupled signal, and processing the resultant signal with circuitry that produces a signal having an amplitude that is a function of the resistivity of the electrode.

Claims

1. An apparatus for inferring the resistivity of an electrode between a stimulation point and a measurement point, wherein a drive signal is introduced into the electrode at the stimulation point by capacitive coupling, and the measurement point is physically electrically coupled to a measurement circuitry comprising an amplifier circuit configured to produce a resultant signal that is a function of the resistivity of the electrode.

2. The apparatus of claim 1, wherein the amplifier circuit comprises a virtual ground amplifier having a virtual ground node, and wherein the measured trace is directly physically electrically coupled to the virtual ground node.

3. The apparatus of claim 2, wherein directly physically electrically coupled comprises the absence of a resistor between the measurement point of the electrode and the virtual ground node.

4. The apparatus of claim 2, wherein directly physically electrically coupled comprises a significantly small resistor is between the measurement point of the electrode and the virtual ground node.

5. The apparatus of claim 2, wherein the resultant signal'"'"'s amplitude is a function of the resistivity of the electrode.

6. The apparatus of claim 5, wherein the resultant signal'"'"'s amplitude is a linear function of the resistivity of the electrode.

7. The apparatus of claim 2, further comprising an analog-to-digital converter coupled to the amplifier circuit to process the resultant signal.

8. The apparatus of claim 2, further comprising a peak detector for detecting the peak voltage of the resultant signal.

9. The apparatus of claim 7, further comprising a low-pass amplifier circuit between the analog-to-digital converter and the amplifier circuit.

10. A touch panel testing device that determines a resistivity for at least some of the electrodes in a mutual capacitive touch panel having a first and second array of electrodes separated by a dielectric and configured such that electrical signals applied an electrode of either array capacitively couple to the electrodes of the other array, comprising:

a drive signal generator electrically coupled to an electrode of the first array;

a measurement circuit physically electrically coupled to at lease one electrode of the second array, the measurement circuit comprising;

a virtual ground amplifier having a virtual ground node, wherein the virtual groud node is physically electrically coupled to the at least one electrode.

11. The touch panel testing device of claim 10, wherein physically electrically coupled comprises the absence of a resistor between the at least one electrode and the virtual ground node.

12. The touch panel testing device of claim 10, wherein directly physical electrical coupled comprises analog circuitry consisting only of one or more significantly small resistors between the virtual ground node and the at least one electrode.