Area-Efficient OLED Sensing Apparatus Using Overlap Sampling
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Solution Overview
Problem
Existing OLED driving circuits face challenges in uniformly sensing mobility and threshold voltage due to non-uniform processing and stress voltage, leading to deviations in luminance across pixels, which requires a more efficient sensing method to reduce area and time while minimizing sample-and-hold portions.
Innovation Solution
An area-efficient sensing apparatus using overlap sampling time, dividing N sensing lines into M groups, with switching portions connecting any one of N/M lines to sample-and-hold portions, and an analog-to-digital converter to convert signals stored in sharing capacitors, allowing for reduced sample-and-hold portions and faster sensing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If N sensing lines are connected to N sample-and-hold portions to sense mobility or threshold voltage for each pixel, then sensing precision is improved, but device area increases significantly
Solution Approach 1:
The patent merges multiple sensing lines into groups where M switching portions connect N sensing lines divided into M groups to M sample-and-hold portions. This consolidation reduces the number of sample-and-hold portions from N to M (where N>M), thereby reducing device area while maintaining sensing capability through sequential multiplexed operation.
Solution Approach 2:
The patent segments N sensing lines into M groups, with each group managed by a switching portion. This segmentation allows systematic multiplexing where switching portions alternatively connect different sensing lines to sample-and-hold portions, enabling area reduction through structured resource sharing while preserving measurement precision.
2Measurement precision
If sequential sensing of mobility and threshold voltage is performed using conventional methods, then measurement completeness is improved, but sensing time increases
Solution Approach 1:
The patent implements overlap sampling time where the sampling capacitor begins storing signals from subsequent sensing lines before the current sensing operation is fully complete. This preliminary action creates overlapping time windows for different sensing operations, allowing mobility and threshold voltage sensing to be performed more quickly without sacrificing measurement completeness.
Solution Approach 2:
The patent maintains continuous useful action by enabling the sampling capacitor to continuously acquire signals from different sensing lines through overlap sampling. Instead of waiting for one sensing operation to complete before starting the next, the system continuously performs sensing operations in an overlapping manner, reducing total sensing time while maintaining measurement accuracy.
3Productivity
If multiple sample-and-hold portions are used to sense signals from multiple sensing lines simultaneously, then sensing speed is improved, but device complexity increases
Solution Approach 1:
The patent makes the sampling capacitor universal by enabling it to service multiple sensing lines through the switching portions. Instead of dedicating a separate sample-and-hold portion to each sensing line, the same sampling capacitor is shared across M groups of sensing lines, reducing device complexity while maintaining sensing speed through time-multiplexed operation.
Solution Approach 2:
The patent introduces dynamic switching through switching portions that alternatively connect different sensing lines to the sample-and-hold portions. This dynamic reconfiguration allows the system to achieve parallel sensing capability without the static complexity of having N separate sample-and-hold portions, as the connection topology changes dynamically based on which sensing line is being processed.
Data Source
AI summary
The present invention relates to an area-efficient apparatus and method for sensing a signal using overlap sampling time. In a preferred embodiment of the present invention, the sensing apparatus sensing a signal which detects degradation of a light-emitting device and transferring the signal to a compensating circuit comprises: M switching portions connected to sensing lines included in each group of M groups into which N sensing lines are divided, where N>M and N and M are natural numbers. The switching portion is characterized by alternatively connecting any one of N/M sensing lines to a sample-and-hold portion.