Display Substrate Dual Test Circuits for Crosstalk-Free Lighting Tests
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Solution Overview
Problem
The issue of crosstalk between test circuits in display substrates during array and lighting tests leads to vertical dark stripes, affecting the accuracy of the lighting test and product yield in OLED display panels.
Innovation Solution
A display substrate design with a first and second test circuit, including a first test control signal bypass, allows for the external application of a control signal to turn off the first test switch circuit in the second test stage, preventing signal crosstalk and eliminating vertical dark stripes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a first test circuit is used to perform array tests on the display substrate, then transistor characteristics can be detected, but signal crosstalk occurs during subsequent lighting tests causing vertical dark stripes
Solution Approach 1:
The patent extracts and removes the first test switch circuit from the signal path during the lighting test stage. By turning off the first test switch circuit after array tests are completed, the source of signal crosstalk is eliminated, allowing lighting tests to proceed without interference and vertical dark stripes to be prevented.
Solution Approach 2:
The patent implements dynamic control of the first test switch circuit by applying a control signal voltage to turn it off during the lighting test stage. This dynamic switching between test modes allows the system to adapt its configuration based on the current testing requirements, preventing crosstalk while maintaining array test functionality when needed.
2Adaptability or versatility
If the first test switch circuit remains on during the second test stage, then array test functionality is maintained, but signal crosstalk causes vertical dark stripes in the display region
Solution Approach 1:
The patent employs periodic action by sequentially switching between array test mode and lighting test mode. During array tests, the first test switch circuit is active; during lighting tests, it is turned off. This periodic activation and deactivation ensures that the circuit functions appropriately for each test type without causing harmful crosstalk effects.
Solution Approach 2:
The patent applies preliminary action by turning off the first test switch circuit before performing lighting tests. This preparatory step prevents signal crosstalk from occurring in the first place, ensuring that the lighting test proceeds without generating vertical dark stripes or other harmful artifacts.
3Reliability
If external signal application circuit is used to turn off the first test switch circuit, then signal crosstalk is prevented, but additional control circuitry is required
Solution Approach 1:
The patent applies universality by designing the external signal application circuit to serve multiple functions: it controls the first test switch circuit during lighting tests, maintains array test functionality when needed, and can be integrated with existing test equipment. This multi-functional approach reduces the need for separate dedicated circuits for each function.
Data Source
Figure 1~2A
Figure 2B~3
Figure 4~5
AI summary
A display substrate and a test method thereof are disclosed. The display substrate includes a base substrate (10), a plurality of data lines (13), a plurality of data leads (14), a first test circuit (50) and a second test circuit (60). The base substrate (10) includes a display region (11) and a peripheral region (12), the display region (11) includes a pixel array (30), and the pixel array (30) includes a plurality of sub-pixels (310); the first test circuit (50) is configured to apply a first test signal to the plurality of sub-pixels (310) to perform a first test in a first test stage; the second test circuit (60) is configured to apply a second test signal to the plurality of sub-pixels (310) to perform a second test in a second test stage. The first test circuit (50) includes a first test switch circuit (510) and a first test control signal application circuit (520), a first test control signal pad (521) of the first test control signal application circuit (520) and the first test control signal bypass (523) are respectively electrically connected to a control terminal of the first test switch circuit (510), and the first test control signal bypass (523) is configured to be electrically connected to an external signal application circuit (70).