Current Detection Circuit Timing for Small OLED Pixel Currents

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Solution Overview

Problem

Existing OLED display technologies face issues with brightness inconsistency due to variations in drive transistor characteristics, particularly at low grayscale levels, leading to inaccurate current detection and uneven display quality.

Innovation Solution

A control method and device for a current detection apparatus that includes a sensing control switch, integration sub-circuit, and multiple samplings to determine the current on a detection line, with specific timing and reset operations to enhance accuracy, especially for small currents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the pixel circuit is reduced to meet brightness requirements, then the luminous efficiency is improved, but the current detection accuracy deteriorates due to small pixel currents

Engineering Contradiction:

Improveluminous efficiencyVSAvoidcurrent detection accuracy

Core Design Contradiction:

Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The sensing control switch is turned on at a first time point before the integration operation starts, allowing the detection line to establish stable balance with the pixel circuit before measurement. This preliminary action ensures that the detection system is ready and stable before the actual small current measurement begins, improving detection accuracy without requiring larger pixel circuits

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The current detection process is divided into multiple sequential stages: a first duration for establishing balance by turning on the sensing control switch before integration, and a second duration for actual integration and sampling. This segmentation allows each stage to optimize for its specific function, ensuring accurate measurement of small pixel currents while maintaining efficient luminous output

Inventive Principle:

Principle #1Segmentation

2Speed

If the integration operation starts immediately, then the detection speed is improved, but the detection accuracy deteriorates due to unstable balance establishment

Engineering Contradiction:

Improvedetection speedVSAvoiddetection accuracy

Core Design Contradiction:

SpeedVSMeasurement precision

Solution Approach 1:

The sensing control switch is activated before the integration operation to pre-establish stable balance between the detection line and pixel circuit. This preliminary preparation ensures that when integration begins, the system is already in a stable state, maintaining both speed and accuracy

Inventive Principle:

Principle #10Preliminary action

3Measurement precision

If multiple samplings are performed, then the detection accuracy is improved, but the detection time increases

Engineering Contradiction:

Improvedetection accuracyVSAvoiddetection time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

Multiple samplings are performed on the integrated voltage signal during the integration process to obtain multiple measurement points. By continuously sampling during the integration duration, the system achieves high detection accuracy through multiple data points without requiring multiple separate integration operations, thus minimizing time loss

Inventive Principle:

Principle #20Continuity of useful action

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

Improves the detection accuracy of small currents, ensuring consistent brightness across pixels and reducing errors in current measurements, thereby enhancing display quality.

Implementation Method 1

controlling the current detection circuit to start the integration operation on a current of the detection line at the integration start time point to obtain an integrated voltage signal corresponding to the detection line

Methodology Applied

Scientific EffectIntegration operation:

Implementation Method 2

controlling the sensing control switch to be in an on state at a first time point before the current detection circuit performs an integration operation on the detection line; a duration between the first time point and an integration start time point at which the current detection circuit starts the integration operation being a first duration

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

turning on the reset control switch to reset a potential of the detection line and a potential of the source electrode of the drive transistor in the pixel circuit to an initial voltage

Methodology Applied

Scientific EffectElectrical potential control:

Data Source

PatentUS12548482B2Control method and control device for current detection apparatus

Publication Date: 2026.02.10 BOE TECHNOLOGY GROUP CO LTD

AI summary

A control method and a control device for a current detection apparatus are provided, which are used to improve the accuracy of current detected by the current detection apparatus. A sensing control switch is controlled to be in an on state at a first time point before an integration operation is performed on the detection line; a current detection circuit is controlled to start the integration operation on a current of a detection line at the integration start time point to obtain an integrated voltage signal corresponding to the detection line; multiple samplings are performed on the integrated voltage signal, and an output voltage difference between different sampling points is determined; and the current of the detection line is determined based on the output voltage difference.