Adaptive Dithering Circuit for Display Driver IC Mura Reduction
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Solution Overview
Problem
Existing display technologies face challenges in reducing display artifacts like Mura, especially in low-grayscale images, due to limitations in adaptively changing threshold grayscale values based on display brightness.
Innovation Solution
A display driver integrated circuit (IC) with a dithering circuit that calculates reference grayscale values based on display brightness, compares these values with input image data grayscale values, and adjusts the output grayscale values by selecting from a group of threshold grayscale values or minimum grayscale values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a fixed threshold grayscale value is used in existing display technologies, then the device complexity is reduced, but display artifacts like Mura appear especially in low-grayscale images
Solution Approach 1:
The patent implements dynamic adjustment of threshold grayscale values based on display brightness conditions. The dithering circuit receives a brightness value of the display, calculates a reference grayscale value corresponding to the brightness value, and adaptively changes the threshold grayscale value depending on the display brightness value. This dynamic adaptation eliminates fixed threshold limitations and reduces Mura artifacts across varying brightness conditions.
Solution Approach 2:
The patent changes the parameter of threshold grayscale value from a fixed constant to a variable that depends on display brightness. By calculating reference grayscale values based on brightness values and using these to dynamically adjust threshold grayscale values, the system optimizes display quality for different brightness conditions while managing circuit complexity through systematic parameter transformation.
2Object-affected harmful factors
If adaptively changing threshold grayscale values based on display brightness is implemented, then Mura artifacts are reduced, but the device complexity increases due to additional dithering circuit components
Solution Approach 1:
The dithering circuit is segmented into functional modules: a brightness value receiver that obtains display brightness, a reference grayscale value calculator that computes threshold values based on brightness, and a comparator that adjusts output grayscale values. This modular segmentation manages complexity by organizing the adaptive dithering function into distinct, manageable components rather than a monolithic circuit.
Solution Approach 2:
The reference grayscale value acts as an intermediary between the brightness value input and the threshold grayscale value output. The calculator circuit generates this intermediate reference value that mediates the relationship between display brightness conditions and the appropriate threshold grayscale value, enabling adaptive adjustment without direct complex interconnections.
3Object-affected harmful factors
If reference grayscale value calculation based on brightness value is performed, then image quality is improved by reducing artifacts, but processing time increases
Solution Approach 1:
The system performs preliminary calculation of reference grayscale values based on brightness values in advance, before actual image data processing. By pre-computing the threshold grayscale values corresponding to different brightness conditions, the system avoids time-consuming calculations during real-time image rendering, thus reducing processing time while maintaining image quality.
Data Source
AI summary
A display driver integrated circuit (IC) includes a data line driver that drives a first data line connected with a first pixel of a display in response to output image data, and a dithering circuit that receives a brightness value of the display, calculates a first reference grayscale value corresponding to the brightness value using a first group of threshold grayscale values, receives input image data with a first grayscale value, which corresponds to the first pixel, compares the first grayscale value and the first reference grayscale value, and generates the output image data having not the first grayscale value but an output grayscale value when the first grayscale value is smaller than the first reference grayscale value.