Differential pixel test for capacitive touch screens
First Claim
1. A process for testing pixels of a capacitive touch panel, the process comprising:
- determining, by a test system coupled to a capacitive touch panel, pixel values representative of mutual capacitances of pixels of the capacitive touch panel, each of the pixels corresponding to a capacitor formed at an intersection between a drive line and a sense line of the capacitive touch panel, wherein the determining involves;
causing an electrical current source to drive a plurality of drive lines to generate a local electric field at each pixel of a plurality of pixels; and
obtaining signals, from sense lines of the capacitive touch panel, corresponding to the mutual capacitances;
generating, by the test system, a pixel value matrix that includes the pixel values arranged in a plurality of rows and a plurality of columns;
for each column of pixel values in the pixel value matrix, determining, by the test system, first difference values between the respective pixel values in the column and respective pixel values in an adjacent column;
generating, by the test system, an intermediate matrix that includes the first difference values arranged in associated rows and columns;
for each row of first difference values in the intermediate value matrix, determining, by the test system, second difference values between the respective first difference values in the row with respective first difference values in an adjacent row;
generating, by the test system, a difference matrix that includes the second difference values arranged in associated rows and columns;
comparing, by the test system, one or more of the second difference values in the difference matrix to one or more threshold values; and
determining, by the test system, whether one or more of the pixels of the capacitive touch panel are defective, based on the comparisons.
4 Assignments
0 Petitions
Accused Products
Abstract
Techniques are described for testing a capacitive touch panel for the presence or absence of discontinuities. A pixel matrix is determined for a capacitive touch panel. The pixel matrix comprises pixel values representative of mutual capacitance of respective pixels of the capacitive touch panel. A difference matrix is generated from the pixel matrix. The difference matrix contains differences in pixel values for respective pixels of the capacitive touch panel with respect to pixel values of adjacent pixels. A determination may then be made from the difference matrix whether respective ones of the pixels of the capacitive touch panel contain a discontinuity.
-
Citations
26 Claims
-
1. A process for testing pixels of a capacitive touch panel, the process comprising:
-
determining, by a test system coupled to a capacitive touch panel, pixel values representative of mutual capacitances of pixels of the capacitive touch panel, each of the pixels corresponding to a capacitor formed at an intersection between a drive line and a sense line of the capacitive touch panel, wherein the determining involves; causing an electrical current source to drive a plurality of drive lines to generate a local electric field at each pixel of a plurality of pixels; and obtaining signals, from sense lines of the capacitive touch panel, corresponding to the mutual capacitances; generating, by the test system, a pixel value matrix that includes the pixel values arranged in a plurality of rows and a plurality of columns; for each column of pixel values in the pixel value matrix, determining, by the test system, first difference values between the respective pixel values in the column and respective pixel values in an adjacent column; generating, by the test system, an intermediate matrix that includes the first difference values arranged in associated rows and columns; for each row of first difference values in the intermediate value matrix, determining, by the test system, second difference values between the respective first difference values in the row with respective first difference values in an adjacent row; generating, by the test system, a difference matrix that includes the second difference values arranged in associated rows and columns; comparing, by the test system, one or more of the second difference values in the difference matrix to one or more threshold values; and determining, by the test system, whether one or more of the pixels of the capacitive touch panel are defective, based on the comparisons. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A test system capable of testing pixels of a capacitive touch panel, the test system comprising:
-
a memory operable to store one or more modules; apparatus for coupling the test system to a capacitive touch panel; and a processor operable to execute the one or more modules to; determine pixel values representative of mutual capacitances of pixels of the capacitive touch panel, each of the pixels corresponding to a capacitor formed at an intersection between a drive line and a sense line of the capacitive touch panel, wherein the determining involves; causing an electrical current source to drive a plurality of drive lines to generate a local electric field at each pixel of a plurality of pixels; and obtaining signals, from sense lines of the capacitive touch panel, corresponding to the mutual capacitances; generate a pixel value matrix that includes the pixel values arranged in a plurality of rows and a plurality of columns; for each column of pixel values in the pixel value matrix, determine first difference values between the respective pixel values in the column and respective pixel values in an adjacent column; generate an intermediate matrix that includes the first difference values arranged in associated rows and columns; for each row of first difference values in the intermediate value matrix, determine second difference values between the respective first difference values in the row with respective first difference values in an adjacent row; generate a difference matrix that includes the second difference values arranged in associated rows and columns; compare one or more of the second difference values in the difference matrix to one or more threshold values; and determine whether one or more of the pixels of the capacitive touch panel are defective based on the comparisons. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
-
-
19. One or more tangible computer-readable storage media storing computer executable instructions for testing pixels of a capacitive touch panel, the computer executable instructions comprising instructions for:
-
determining, by a test system coupled to a capacitive touch panel, pixel values representative of mutual capacitances of pixels of the capacitive touch panel, each of the pixels corresponding to a capacitor formed at an intersection between a drive line and a sense line of the capacitive touch panel, wherein the determining involves; causing an electrical current source to drive a plurality of drive lines to generate a local electric field at each pixel of a plurality of pixels; and obtaining signals, from sense lines of the capacitive touch panel, corresponding to the mutual capacitances; generating, by the test system, a pixel value matrix that includes the pixel values arranged in a plurality of rows and a plurality of columns; for each column of pixel values in the pixel value matrix, determining, by the test system, first difference values between the respective pixel values in the column and respective pixel values in an adjacent column; generating, by the test system, an intermediate matrix that includes the first difference values arranged in associated rows and columns; for each row of first difference values in the intermediate value matrix, determining, by the test system, second difference values between the respective first difference values in the row with respective first difference values in an adjacent row; generating, by the test system, a difference matrix that includes the second difference values arranged in associated rows and columns; comparing, by the test system, one or more of the second difference values in the difference matrix to one or more threshold values; and determining, by the test system, whether one or more of the pixels of the capacitive touch panel are defective based on the comparisons. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26)
-
Specification