Substrate testing device and method thereof
View Patent ↗Exemplary embodiments relate to a substrate testing device having a comparator adapted to compare a power supply voltage supplied by a power supply voltage line with a dropped power supply voltage detected by a power supply voltage detection line and to output a voltage difference, and a level shifter circuit adapted to compensate a data voltage with a voltage up to an amount equal to the voltage difference output from the comparator and to supply the data voltage to a display panel.
1. A substrate testing device detecting a defect in image quality of a display panel being tested for the defect in image quality, the substrate testing device, comprising:
a comparator comparing a power supply voltage supplied by a power supply voltage line to the display panel being tested for the defect in image quality with a dropped power supply voltage detected by a power supply voltage detection line from the display panel being tested for the defect in image quality, and the comparator outputting a voltage difference; and
a level shifter circuit compensating a data voltage with a voltage up to an amount equal to the voltage difference output from the comparator, and supplying the data voltage to the display panel being tested for the defect in image quality.
2. The substrate testing device as claimed in claim 1 , further comprising:
an initialization level shifter circuit compensating an initialization voltage with a second voltage up to an amount equal to the voltage difference output from the comparator, and supplying the initialization voltage to the display panel being tested for the defect in image quality.
3. The substrate testing device as claimed in claim 2 , wherein:
the initialization level shifter circuit receives the voltage difference from the comparator, and
the initialization voltage is a voltage is transferred to a pixel circuit of the display panel being tested for the defect in image quality.
4. The substrate testing device as claimed in claim 2 , wherein the display panel being tested for the defect in image quality is electrically connected with the power supply voltage, the initialization voltage, and the data voltage.
5. The substrate testing device as claimed in claim 4 , wherein the power supply voltage detection line is electrically connected with the power supply voltage line of the display panel being tested for the defect in image quality.
6. The substrate testing device as claimed in claim 1 , wherein:
the level shifter circuit receives the data voltage from the comparator, and
the data voltage is a voltage transferred to a pixel circuit of the display panel being tested for the defect in image quality.
7. The substrate testing device as claimed in claim 1 , further comprising:
a substrate on which a plurality of display panels are arranged in a matrix,
wherein the substrate testing device detects the defect in image quality in at least one of the plurality of display panels on the substrate.
8. The substrate testing device as claimed in claim 7 , wherein the comparator, the level shifter circuit and the initialization level shifter circuit are integrated into the substrate.
9. The substrate testing device as claimed in claim 4 , wherein the data voltage is at least one of a red data voltage, a green data voltage, and a blue data voltage.
10. The substrate testing device as claimed in claim 1 , further comprising a comparator switch for switching the comparator.
11. The substrate testing device as claimed in claim 1 , further comprising a voltage switch for switching the level shifter circuit.
12. The substrate testing device as claimed in claim 2 , further comprising an initialization switch for switching the initialization level shifter circuit.
13. The substrate testing device as claimed in claim 1 , further comprising a voltage difference holder for holding a voltage output from the comparator.
14. A substrate testing method for detecting a defect in image quality of a display panel being tested for the defect in image quality, the substrate testing method comprising:
detecting a power supply voltage being supplied to the display panel from a power supply source during testing for the defect in image quality;
detecting a dropped power supply voltage from the display panel during testing for the defect in image quality;
comparing the power supply voltage with the dropped power supply voltage;
outputting an output voltage based on the comparison between the power supply voltage and the dropped power supply voltage during testing for the defect in image quality;
compensating a data voltage to be supplied to the display panel with a voltage up to an amount equal to the output voltage; and
supplying a compensated data voltage that includes the data voltage and the voltage up to the amount equal to the output voltage to the display panel during testing for the defect in image quality.
15. The method as claimed in claim 14 , wherein outputting the output voltage includes outputting a voltage difference between the power supply voltage with the dropped power supply voltage.
16. The method as claimed in claim 14 , further comprising compensating an initialization voltage to be supplied to the display panel during testing for the defect in image quality with a second voltage up to an amount equal to the output voltage.
17. The method as claimed in claim 14 , wherein compensating the data voltage compensates all of a red data voltage, a green data voltage and a blue data voltage.
18. The method as claimed in claim 14 , wherein compensating the data voltage with a voltage up to an amount equal to the outputted voltage outputs the compensated data voltage which is produced by downshifting a voltage difference between the power supply voltage and the dropped power supply voltage in a level shifter.
19. The method as claimed in claim 14 , further comprising switching the comparator after compensating the data voltage with a voltage up to an amount equal to the output voltage.
20. The method as claimed in claim 14 , further comprising switching the level shifter circuit after compensating the data voltage with a voltage up to an amount equal to the output voltage.
21. The method as claimed in claim 16 , further comprising switching the initialization level shifter after compensating the data voltage with a voltage up to an amount equal to the output voltage.
22. The method as claimed in claim 16 , wherein compensating the initialization voltage with a voltage up to an amount equal to the output voltage outputs a compensated initialization voltage which is produced by downshifting a voltage difference between the power supply voltage and the dropped power supply voltage in an initialization level shifter.
23. The method as claimed in claim 14 , further comprising comparing the power supply voltage with the dropped power supply voltage, and holding a voltage difference, so as to output a constant voltage after compensating the data voltage with a voltage up to an amount equal to the output voltage.
24. The method as claimed in claim 14 , further comprising applying the compensated data voltage to the display panel during testing for the defect in image quality, after compensating the data voltage with a voltage up to an amount equal to the output voltage.