Electronic Device Test Elements for Pre-SMT Transistor Defect Detection
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Solution Overview
Problem
Existing active matrix light-emitting diode (AMOLED) manufacturing processes lack a method to test the functionality of thin film transistors before the surface mount technology (SMT) process, leading to wasted LEDs if defects are discovered post-SMT.
Innovation Solution
Incorporating a test element with higher impedance than the electronic unit, connected in parallel, to detect transistor defects by measuring thermal energy generated from leakage currents when the transistor is unable to turn off, allowing pre-SMT defect identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If light-on inspection is performed after SMT process, then LED defects can be detected, but LED waste increases and processing cost rises
Solution Approach 1:
The patent applies preliminary action by performing transistor functionality testing before the SMT process. A test element is coupled to the transistor, and a testing signal is applied to verify transistor operation prior to LED mounting. This early detection prevents defective LEDs from proceeding through subsequent manufacturing steps, thereby reducing LED waste while maintaining reliability through pre-screening.
2Loss of substance
If testing is performed before SMT process, then LED waste is reduced, but manufacturing process complexity increases
Solution Approach 1:
The patent introduces a test element as an intermediary component that simplifies the testing process. This test element is specifically designed to interface with the transistor, allowing functionality verification through a standardized testing mechanism. The intermediary test element acts as a bridge between the transistor and the testing signal, enabling efficient pre-SMT testing without significantly complicating the overall manufacturing process.
3Measurement precision
If test element with higher impedance is used, then leakage current detection is improved, but energy consumption increases
Solution Approach 1:
The patent applies parameter changes by selecting a test element with specifically optimized impedance characteristics. The test element is designed with higher impedance than the transistor to maximize sensitivity for detecting leakage currents. By carefully controlling the impedance parameter of the test element, the system achieves improved measurement precision for leakage current detection while managing energy consumption through proper parameter selection rather than excessive energy input.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables efficient pre-SMT detection of transistor defects, reducing waste and processing costs by identifying and addressing issues before the SMT process, thus ensuring functional LEDs.
Implementation Method 1
detect transistor defects by measuring thermal energy generated from leakage currents
Data Source
Figure 1
Figure 2(a)~2(c)
Figure 3
AI summary
An electronic device includes a first sub-pixel and a test element. The first sub-pixel includes a first transistor, and a first electronic unit. The first electronic unit is electrically connected to the first transistor. The test element is electrically connected to the first transistor. The test element has a first impedance, the first electronic unit has a second impedance, and the first impedance is higher than the second impedance.