Per-Pixel Gamma Offset for OLED Color Shift Elimination
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Solution Overview
Problem
Display devices, particularly organic light emitting display devices, face challenges in adjusting luminance uniformly across the panel, leading to color shift issues during dimming, as the luminance adjustment methods like impulse driving struggle to compensate for variations in thin film transistor characteristics across pixels.
Innovation Solution
A method is introduced where a gamma reference voltage is set with per-pixel offsets, using a dimming controller to generate corrected gamma reference voltages by determining a second gamma correcting offset based on the characteristics of each pixel, ensuring that the process deviation does not affect dimming and preventing color shift by applying specific offsets to each pixel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a uniform gamma reference voltage is applied to all pixels, then the device complexity is reduced, but color shift occurs due to variations in thin film transistor characteristics across pixels
Solution Approach 1:
The patent applies local quality by setting different gamma correcting offsets for different pixels based on their individual characteristics. Specifically, pixels are divided into a reference pixel and other pixels, with the latter receiving an additional offset value determined by their thin film transistor characteristics. This localized adjustment compensates for manufacturing variations while maintaining overall system functionality.
2Illumination intensity
If impulse driving method is used to dim the display, then luminance adjustment is achieved, but color shift occurs during dimming due to process deviation
Solution Approach 1:
The patent changes the parameter of gamma reference voltage by adding a correcting offset specific to each pixel. This parameter modification compensates for process deviation that occurs during impulse driving dimming, ensuring that color accuracy is maintained across different luminance levels despite variations in thin film transistor characteristics.
3Manufacturing precision
If per-pixel gamma correcting offset is applied, then color shift is eliminated and manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the pixel population into a reference pixel and other pixels, applying different gamma correcting offset strategies to each segment. The reference pixel receives a base offset while other pixels receive an additional offset determined by their specific characteristics. This segmentation approach manages complexity by creating a systematic differentiation rather than fully individualized control for every pixel.
Data Source
AI summary
In accordance with an embodiment, a display device may include a display panel including a plurality of pixels, a dimming controller for setting a first gamma correcting offset of a reference pixel among the plurality of pixels, setting a second gamma correcting offset of at least one pixel other than the reference pixel among the plurality of pixels, and generating a corrected gamma reference voltage per pixel using the first gamma correcting offset and the second gamma correcting offset and a data driver applying the corrected gamma reference voltage to each pixel of the display panel. According to an embodiment, there may be provided a display device capable of eliminating color shift by setting an offset for a gamma reference voltage per pixel and a driving method of the same.