Display Driver IC Bond Resistance Measurement Circuit
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Solution Overview
Problem
Forming satisfactory low-resistance bonds in chip-on-glass and flex-on-glass arrangements is challenging, leading to potential high or unreliable resistance in display driver integrated circuits, which can affect the reliability and performance of electronic devices.
Innovation Solution
Incorporating bond resistance measurement circuitry within the display driver integrated circuit, using test equipment to apply currents and measure voltages through flexible printed circuits, allowing for the quantification of bond resistances between the display driver integrated circuit and the substrate, and between the flexible printed circuit and the substrate, ensuring low and stable resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If chip-on-glass or flex-on-glass bonding is used to mount display driver integrated circuits, then integration density is improved, but bond resistance becomes high or unreliable
Solution Approach 1:
The patent incorporates bond resistance measurement circuitry and test switches into the display driver integrated circuit before final assembly. During manufacturing, test equipment can activate these switches to measure bond resistances through the flexible printed circuit and anisotropic conductive adhesive bonds, allowing early detection and correction of bonding issues before the product reaches the customer.
Solution Approach 2:
The patent implements a feedback mechanism where bond resistance measurements are taken during manufacturing and compared against acceptable thresholds. The measurement circuitry provides real-time feedback on bond quality, enabling manufacturers to adjust bonding parameters or replace defective components while still under control, thereby improving overall bond reliability.
2Adaptability or versatility
If multiple display driver integrated circuits are used in a display, then display functionality is improved, but coordination overhead increases
Solution Approach 1:
The patent merges the functionality of multiple display driver integrated circuits by having them share common reference voltages through a master-slave architecture. The master circuit generates reference voltages that are distributed to slave circuits, eliminating the need for each circuit to independently generate and coordinate these voltages, thereby reducing coordination overhead while maintaining enhanced display functionality.
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
This approach ensures the formation of satisfactory bonds by monitoring and adjusting bond resistance during manufacturing, enhancing the reliability and performance of electronic devices by maintaining low and stable resistance in chip-on-glass and flex-on-glass configurations.
Implementation Method 1
test equipment may apply currents to pads in the display driver integrated circuit through the flexible printed circuit while controlling the switching circuitry and making voltage measurements
Data Source
AI summary
A display may have a substrate layer to which a display driver integrated circuit and flexible printed circuit are bonded. The display driver integrated circuit may be provided with switches and control circuitry for controlling the operation of the switches during bond resistance measurements. Test equipment may apply currents to pads in the display driver integrated circuit through contacts in the flexible printed circuit while controlling the switching circuitry. Based on these measurements and the measurement of trace resistances in a dummy flexible printed circuit, the test equipment may determine bond resistances for bonds between the display driver integrated circuit and the display substrate and between the flexible printed circuit and the display substrate. Displays may have master and slave display driver integrated circuits that share coarse reference voltages produced by the master from raw power supply voltages.