OLED Initialization Voltage for Display Defect Prevention
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Solution Overview
Problem
Organic light emitting display apparatuses face display defects such as color blurring and luminance deficits, particularly when displaying low gray scale images or dynamic images due to varying driving durations of pixels, which worsen with increasing display resolution.
Innovation Solution
A method and apparatus that selectively apply an initialization voltage to OLEDs in each pixel based on grayscale checking operations, enabling a black current bypass operation to prevent display defects and improve color and luminance variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If display resolution is increased, then image quality is improved, but driving duration of pixels decreases causing luminance deficit and display defects
Solution Approach 1:
The patent applies an initialization voltage to the OLED before the actual driving period to pre-charge the device and ensure sufficient luminance output during the shortened driving duration caused by high resolution requirements
2Speed
If driving duration is decreased for high resolution, then pixel response time is reduced, but luminance output becomes insufficient causing display defects
Solution Approach 1:
The initialization voltage is applied in advance to prepare the OLED for rapid response while ensuring sufficient luminance output during the shortened driving period
Solution Approach 2:
The patent changes the voltage parameter by applying an initialization voltage different from the normal driving voltage to optimize both response time and luminance output for high resolution displays
3Use of energy by moving object
If low gray scale images are displayed, then power consumption is reduced, but color blurring and luminance deficits occur
Solution Approach 1:
The initialization voltage is applied before displaying low gray scale images to prevent color blurring and luminance deficits while maintaining the low power consumption benefits of displaying low gray scale content
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 method enhances display quality by preventing color blurring and luminance issues, ensuring improved performance even in dynamic or low gray scale image scenarios.
Implementation Method 1
Holes from the anode may be combined with electrons from the cathode in the organic layer between the anode and the cathode to emit light
Data Source
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AI summary
A display apparatus includes a display panel and a panel driver. The display panel includes a first pixel including a first organic light emitting diode (OLED). The panel driver applies a first voltage to an anode electrode of the first OLED while a first frame image is displayed on the display panel if a grayscale of the first frame image is lower than a first reference grayscale and therefore considered as a black or almost black image.