Pixel Circuit Testing Architecture Using Sequential Switching
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Solution Overview
Problem
Conventional liquid crystal display panel test architectures face challenges in precisely detecting the functionality of each pixel circuit during manufacturing due to high costs and manufacturing difficulties associated with the high density of test pads, which often leads to shared test pads and reduced precision in fault detection.
Innovation Solution
A test architecture utilizing a selector with main and auxiliary thin-film transistors and IC pads, allowing for sequential control of signal lines and test pads to individually test and measure pixel circuits, reducing the number of test pads required while maintaining precise functionality detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If one test pad is allocated to each data line for precise pixel circuit detection, then measurement precision is improved, but device complexity and manufacturing cost increase due to high density of test pads
Solution Approach 1:
The patent divides the test pad resource into multiple time slots, where each data line is assigned to a specific time slot for testing. The test pad is segmented in the time domain rather than being physically divided, allowing sequential testing of multiple data lines through the single test pad with the help of switching circuits.
Solution Approach 2:
The patent introduces dynamic switching circuits that can dynamically connect different data lines to the test pad at different times. This dynamic reconfiguration allows the system to adapt the connection topology based on testing requirements, enabling precise detection of individual pixel circuits while sharing the test pad resource.
2Device complexity
If multiple data lines share one test pad to reduce manufacturing cost, then device complexity is reduced, but measurement precision deteriorates as individual pixel circuit detection becomes impossible
Solution Approach 1:
The patent implements periodic testing sequences where each data line is systematically tested in turn through the shared test pad. By assigning specific time periods to specific data lines and using switching circuits to establish appropriate connections during each period, the system achieves individual pixel circuit detection capability while sharing the test pad resource.
Solution Approach 2:
The patent introduces switching circuits as intermediary components between the data lines and the test pad. These switching circuits act as mediators that selectively connect different data lines to the test pad at different times, enabling precise individual detection while allowing multiple data lines to share the single test pad resource.
3Manufacturing precision
If high resolution display is implemented, then product quality is improved, but manufacturing difficulty increases due to insufficient space for test pads and probes
Solution Approach 1:
The patent transitions from a spatial distribution of test pads (one per data line) to a temporal distribution approach. By adding the time dimension to the testing architecture, the system can test multiple high-density data lines through a single test pad sequentially, making the manufacturing process feasible for high-resolution displays where physical space is limited.
Data Source
AI summary
A display device has a display panel, which includes a plurality of IC pads, a plurality of data lines, a selector, a plurality of switches and a test pad. The IC pads are connected to the data lines through the selector. The data lines are electrically connected to a corresponding pixel circuit. The IC pads are connected to the test pad via the corresponding switch. The switches are sequentially turned on to sequentially transmit a voltage to the corresponding pixel circuit through the test pad.