Display Driving Circuit Flicker Compensation via Initialization Periods

Solution Overview

Problem

Electronic devices with displays experience flicker phenomena when the display driving circuit operates at low frequencies, leading to luminance changes and user-perceived screen flicker due to leakage currents in transistors.

Innovation Solution

The method involves setting specific periods for data voltage supply and emission signal control in the display driving circuit, including an address period and a holding period, with initialization voltage adjustments to maintain consistent luminance and reduce flicker effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by stationary object

If the display driving circuit operates at low frequency to reduce power consumption, then energy efficiency is improved, but leakage current increases causing luminance instability and flicker

Engineering Contradiction:

Improvepower consumptionVSAvoidluminance stability

Core Design Contradiction:

Use of energy by stationary objectVSReliability

Solution Approach 1:

The patent applies preliminary action by performing initialization of pixel transistors before the actual display period at low frequency operation. The initialization transistor is activated in an initialization period prior to the display period to reset the pixel circuit state, compensating for leakage current effects before they manifest as visible luminance instability or flicker during the subsequent display period.

Inventive Principle:

Principle #10Preliminary action

2Use of energy by stationary object

If the display driving circuit operates at low frequency, then power consumption decreases, but flicker phenomenon increases due to leakage current

Engineering Contradiction:

Improvepower consumptionVSAvoidflicker phenomenon

Core Design Contradiction:

Use of energy by stationary objectVSObject-generated harmful factors

Solution Approach 1:

The patent applies preliminary action by performing initialization of pixel transistors before the actual display period at low frequency operation. The initialization transistor is activated in an initialization period prior to the display period to reset the pixel circuit state, compensating for leakage current effects before they manifest as visible luminance instability or flicker during the subsequent display period.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies periodic action by introducing a distinct initialization period that repeats before each display period at low frequency operation. This periodic initialization sequence (initialization period followed by display period) systematically resets pixel circuits at regular intervals, preventing the accumulation of leakage current effects that would otherwise cause flicker.

Inventive Principle:

Principle #19Periodic action

3Illumination intensity

If data voltage is supplied continuously to maintain luminance, then brightness stability is improved, but power consumption increases

Engineering Contradiction:

Improveluminance stabilityVSAvoidpower consumption

Core Design Contradiction:

Illumination intensityVSUse of energy by stationary object

Solution Approach 1:

The patent applies segmentation by dividing the operational cycle into two distinct periods: an initialization period for resetting pixel circuits and a display period for actual image rendering. During the initialization period, initialization voltage is supplied to compensate for leakage; during the display period, data voltage is supplied for normal operation. This segmentation allows targeted voltage application only when needed, maintaining luminance stability while minimizing unnecessary power consumption.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies periodic action by introducing a distinct initialization period that repeats before each display period at low frequency operation. This periodic initialization sequence (initialization period followed by display period) systematically resets pixel circuits at regular intervals, preventing the accumulation of leakage current effects that would otherwise cause flicker.

Inventive Principle:

Principle #19Periodic 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

This approach effectively compensates for luminance differences and decreases flicker phenomena, ensuring stable screen display even at low frequency operations by managing the data voltage and emission signal timing.

Implementation Method 1

When the driving transistor is driven, a light-emitting element such as an organic light-emitting diode (OLED) may emit a light with specified luminance

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentUS11955077B2Electronic device comprising display, and method for driving display

Publication Date: 2024.04.09 SAMSUNG ELECTRONICS CO LTD

AI summary

An electronic device may include: a housing; a display which is viewed through at least a portion of the housing and which displays a screen image by using a plurality of pixels; a display driving circuit for providing, to the display, a data voltage an emission signal for driving each of the plurality of pixels; and a processor operationally connected to the display and the display driving circuit. The processor can be configured to set a first frame driven by the display, and the display driving circuit can be configured to set a first period in which the data voltage is supplied to a first transistor in each of the plurality of pixels and a second period in which the data voltage written in the first period is maintained and to change the initialization voltage to be supplied to the plurality of pixels in the second period. Various other embodiments identified from the specification are also possible.