LED Pixel Sensing Circuit for Accurate Exponential Current Detection
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Solution Overview
Problem
Conventional sensing methods for display devices assume linear current flow, which is inaccurate as actual transistors and diodes operate with exponential current, leading to low precision in sensing pixel characteristics.
Innovation Solution
A display device design that includes a sensing channel with an amplifier and switches to accurately sense exponential current, using a first switch and a second switch with non-overlapping turn-on periods to isolate sensing phases, and transistors and capacitors to measure diode voltage, threshold voltage, and mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional sensing methods using integrators are used, then the sensing circuit is simple, but the sensing precision is low because they assume linear current flow which does not match actual exponential current behavior
Solution Approach 1:
The patent changes the sensing approach from assuming linear current to accurately measuring exponential current by using an amplifier-based circuit that can handle the non-linear current characteristics of actual transistors and diodes, thereby improving sensing precision without excessive complexity increase
Solution Approach 2:
The patent replaces the conventional integrator-based sensing mechanism with an amplifier-based electrical sensing system that can accurately process exponential current signals, substituting a simpler mechanical integration approach with a more sophisticated but precise electrical measurement system
2Measurement precision
If switches are used to isolate sensing phases, then measurement accuracy is improved, but the device complexity increases due to additional switches and control logic
Solution Approach 1:
The patent employs periodic switching actions where the first and second switches operate in alternating periods to sequentially perform different sensing functions (diode voltage sensing and threshold voltage sensing), improving measurement accuracy through phased isolation while managing complexity through systematic timing control
Solution Approach 2:
The sensing process is segmented into distinct phases using switches, where different sensing operations are performed in separate time periods, allowing accurate measurement of different voltage parameters without interference while organizing complexity through structured phase separation
Data Source
AI summary
A display device includes: a pixel including a light emitting element; and a sensing channel connected to a first electrode of the light emitting element by a first sensing line, and connected to a second electrode of the light emitting element by a second sensing line. The sensing channel includes: an amplifier including a first input terminal connected to the second sensing line; and a first switch which connects an output terminal of the amplifier to the first sensing line.