OLED Power Supply Merging for Luminance Consistency
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Solution Overview
Problem
Conventional organic light emitting displays face issues with voltage ripples in separate power sources for reference and first power, leading to inconsistent pixel luminance and image quality degradation due to external noise.
Innovation Solution
An organic light emitting display system with a data driver, scan driver, power source unit, first and second voltage dividers, and switches to generate and select reference powers, ensuring stable voltage and noise resistance by controlling the switches to transmit appropriate reference powers to the data driver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate power sources are used for reference power (Vref) and first power (ELVDD), then power supply flexibility is improved, but voltage ripples cause inconsistent pixel luminance and image quality degradation
Solution Approach 1:
The patent merges the reference power and first power into a single power source (ELVDD) to ensure that both signals experience the same voltage ripples simultaneously. This synchronization prevents differential ripple effects that cause luminance inconsistency, while voltage divider circuits and switching mechanisms maintain the necessary signal differentiation. The merging resolves the contradiction by eliminating the harmful phase difference between ripples while preserving power supply flexibility through controlled signal derivation.
2Device complexity
If separate power sources are used for reference power (Vref) and first power (ELVDD), then power supply configuration is simplified, but external noise affects luminance differently in each channel
Solution Approach 1:
The patent combines both power channels into a single ELVDD power source, ensuring that external noise affects both the reference power and first power equally and simultaneously. This common-mode noise approach eliminates differential noise effects that would otherwise cause luminance inconsistency. The unified power supply configuration simplifies the system while immune to common external interference.
3Power
If voltage ripples are present in separate power sources, then power delivery is maintained, but storage capacitor charging timing becomes inconsistent across pixels
Solution Approach 1:
The patent merges the power delivery into a single ELVDD source that simultaneously provides power to both the reference signal and the first power channel. This ensures that voltage ripples occur at identical timing in both channels, making the charging/discharging cycles of storage capacitors synchronized across all pixels. The unified timing reference eliminates inconsistencies in capacitor charging while maintaining adequate power delivery to all components.
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
The system achieves consistent pixel luminance and improved image quality by stabilizing voltage ripples and reducing noise effects, ensuring desired luminance and preventing image quality deterioration.
Implementation Method 1
a first voltage divider for dividing the first power to generate a first reference power
Implementation Method 2
a second voltage divider for dividing a power from an external power source to generate a second reference power
Implementation Method 3
a switch for transmitting one of the first reference power or the second reference power to the data driver
Data Source
AI summary
An organic light emitting display having an improved image quality. The organic light emitting display includes a data driver for supplying a data signal to data lines; a scan driver for supplying a scan signal to scan lines; pixels at crossing regions between the data lines and the scan lines; a power source unit for generating a first power; a first voltage divider for dividing the first power to generate a first reference power; a second voltage divider for dividing a power from an external power source to generate a second reference power; and a switch to transmit one of the first reference power or the second reference power to the data driver. Each of the pixels includes an organic light emitting diode that emits light when a current flows from the first power to the second power.