Touch display panel and test method for testing short circuit or open circuit

1. A touch display panel, comprising:

a lower substrate where a common electrode layer, a first test pad, and a second test pad are formed,

an upper substrate disposed above the common electrode layer,

a liquid crystal layer sandwiched between the upper substrate and the lower substrate,

wherein the common electrode layer is divided into a plurality of common electrode blocks, every two of the plurality of common electrode blocks which are adjacent in a row direction are coupled to the first test pad and the second test pad, respectively, and every two of the plurality of common electrode blocks which are adjacent in a column direction are coupled to the first test pad and the second test pad, respectively.

2. The touch display panel as claimed in claim 1 , wherein the plurality of common electrode blocks are arranged in a matrix.

3. The touch display panel as claimed in claim 1 , wherein a first control pad and a plurality of first switch elements are formed on the lower substrate,

wherein at least one of the plurality of first switch elements is coupled between one of the common electrode blocks and one of the first test pad and the second test pad, and

the first control pad is connected to control terminals of the plurality of first switch elements.

4. The touch display panel as claimed in claim 3 , wherein a plurality of data lines, a second control pad and a plurality of second switch elements are formed on the lower substrate,

wherein at least one of the plurality of data lines is connected to one of the first test pad and the second test pad via one of the plurality of the second switch elements, and

the second control pad is connected to control terminals of the plurality of second switch elements.

5. The touch display panel as claimed in claim 3 , wherein an area of the lower substrate protrudes with respect to an edge of the upper substrate, and

the first test pad, the second test pad, and the first control pad are formed on the area of the lower substrate.

6. The touch display panel as claimed in claim 1 , wherein the common electrode block is a quadrilateral and the length of each side of the quadrilateral is 1 mm˜5 mm.

7. The touch display panel as claimed in claim 1 , wherein the upper substrate is a color filter substrate and the lower substrate is a thin film transistor substrate.

8. A touch display panel, comprising:

a lower substrate where a common electrode layer is formed,

an upper substrate disposed above the common electrode layer,

a liquid crystal layer sandwiched between the upper substrate and the lower substrate,

wherein the common electrode layer is divided into a plurality of common electrode blocks in a matrix, and each of the plurality of common electrode blocks is separately coupled to a metal wire extending to an edge of the lower substrate,

the metal wires coupled to every two of the plurality of common electrode blocks adjacent in a row direction are different wires, and the metal wires coupled to every two of the plurality of common electrode blocks adjacent in a column direction are different wires.

9. A test method of a touch display panel, the touch display panel comprising: a plurality of pixel electrodes, a plurality of common electrode blocks, a first test pad, and a second test pad, wherein any two adjacent common electrode blocks of the plurality of common electrode blocks are separately coupled to the first test pad and the second test pad,

wherein the test method is a common electrode short circuit test method comprising:

charging the plurality of pixel electrodes to the same voltage level,

providing a first voltage level to the first test pad and a second voltage level not equal to the first voltage level to the second test pad so as to make the touch display panel show checkerboard pattern, and

checking whether there are any two adjacent checks showing the same gray level in the checkerboard pattern.

10. The test method as claimed in claim 9 , wherein the touch display panel comprises: a first control pad and a plurality of first switch elements, wherein anyone of the plurality of first switch elements is coupled between one of the common electrode blocks and one of the first test pad and the second test pad, and the first control pad is connected to control terminals of the plurality of first switch elements, and

wherein the common electrode short circuit test method comprises:

providing a predetermined voltage level to the first control pad to turn on the plurality of first switch elements.

11. The test method as claimed in claim 9 , wherein the touch display panel comprises: a plurality of data lines, a second control pad, and a plurality of second switch elements, wherein anyone of the plurality of data lines is connected to one of the first test pad and the second test pad via one of the plurality of the second switch elements, and the second control pad is connected to control terminals of the plurality of second switch elements,

wherein the test method is a discharge method comprising:

conducting the plurality of pixel electrodes with the plurality of data lines,

providing a third voltage level to the first test pad and the test pad, and

providing a predetermined voltage level to the first control pad and the second control pad to turn on the plurality of first switch elements and the plurality of second switch elements to discharge the plurality of pixel electrodes.

12. The test method as claimed in claim 9 , wherein the test method is a common electrode open circuit test method comprising:

charging the plurality of pixel electrodes to the same voltage level,

providing a fourth voltage level to the first test pad and the second test pad so as to make the touch display panel show an image with the same gray level, and

checking whether there is any area with an abnormal gray level on the image.