Measuring circuit, measuring method and measuring device for TFT (thin film transistor) threshold voltage offset

Abstract

The invention provides a measuring circuit, a measuring method and a measuring device for TFT (thin film transistor) threshold voltage offset. The measuring circuit comprises a first switch, a second switch, a capacitor and a control circuit. The first switch is connected with a grid electrode of a thin film transistor and a power supply of the thin film transistor. The second switch is connected with a source electrode of the thin film transistor and the capacitor of the thin film transistor. One end of the capacitor is connected with a drain electrode of the thin film transistor. The control circuit controls the first switch to stay in a connected state within a first preset period, the second switch to stay in a disconnected state within the first preset period, the first switch to stay in a disconnected state within a second preset period after the first preset period, and the second switch to stay in a connected state within the second preset period, so that the thin film transistor is driven to work to generate first threshold voltage. Operations of the first switch and the second switch performed within the first preset period and the second preset period are repeated to acquire second threshold voltage. The threshold voltage offset is acquired according to the first threshold voltage and the second threshold voltage. By the measuring circuit, the measuring method and the measuring device, timeliness and accuracy of measuring the threshold voltage offset of the thin film transistor are improved.

Description

technical field [0001] The present invention relates to the field of display technology, in particular to a measuring circuit, method and equipment for threshold voltage offset of TFT (Thin Film Transistor). Background technique [0002] The opening and closing of the thin film transistor (TFT) is controlled by the gate signal. When the thin film transistor is in the working state for a long time, the action of the gate bias will cause the electrical characteristics of the field effect transistor to become unstable, such as threshold voltage drift. In the design of thin-film transistors, it is necessary to predict their working life according to the short-term threshold voltage drift characteristics. In addition, in order to improve the manufacturing process of thin-film transistors, it is necessary to study the mechanism of threshold voltage drift of thin-film transistors under the action of gate bias. It is necessary to accurately measure the drift characteristics of the t...

AI Technical Summary

Problems solved by technology

The value of the threshold voltage change is obtained by continuously applying voltage to the test sample. At this time, the TNP equipment is seriously occupied. Using a large-scale test equipment TNP, the time period is long, and the test accuracy is average.

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