Digital Analog Converter Grayscale Segmentation Gamma Correction
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Solution Overview
Problem
Conventional digital/analog converters in OLED displays output linear grayscale currents, failing to satisfy the non-linear gamma characteristics of display panels, which results in degraded image quality due to inability to accurately express high-level grayscales.
Innovation Solution
A digital/analog converter that divides grayscale data into multiple ranges and generates corresponding non-linear grayscale currents using both high-order and low-order bit data, applying these currents to pixel circuits to accurately represent image data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional D/A converter outputs linear grayscale currents, then the conversion process is simple, but the non-linear gamma characteristics of the display panel cannot be satisfied and image quality is degraded
Solution Approach 1:
The D/A converter is divided into multiple current output units, each responsible for a specific grayscale range. The converter segments the full grayscale range into multiple sub-ranges, with each segment handled by a dedicated current output unit that generates appropriate non-linear currents for that specific range, thereby achieving gamma correction without requiring a completely complex redesign of the entire converter.
Solution Approach 2:
The D/A converter dynamically selects which current output unit to activate based on the input grayscale data. By using a selector circuit that changes its output based on the grayscale range, the system adapts its behavior dynamically rather than using a fixed linear conversion approach, enabling non-linear gamma characteristics to be satisfied while maintaining manageable converter complexity.
2Manufacturing precision
If a D/A converter is designed to output non-linear grayscale currents for gamma correction, then image quality is improved, but the device complexity increases
Solution Approach 1:
Rather than designing a single complex non-linear D/A converter, the system segments the conversion task into multiple simpler current output units, each handling a specific grayscale range. This segmentation allows each unit to be relatively simple while collectively achieving the required non-linear gamma correction, thus managing overall device complexity.
Solution Approach 2:
Multiple current output units share common components such as the selector circuit and reference current generation mechanisms. This multi-functionality approach allows the system to achieve non-linear gamma correction across different grayscale ranges while avoiding the need for completely separate converter circuits for each range, thereby limiting the increase in device complexity.
Data Source
AI summary
A display device including a display unit including a plurality of data lines for transmitting data currents, a plurality of scan lines for transmitting scan signals, and a plurality of pixel areas defined by the data lines and the scan lines; a data driver for converting a plurality of grayscale data that include first data and second data into at least one of the data currents, and applying the at least one of the data currents to at least one of the data lines; and a scan driver for sequentially applying the scan signals to the plurality of scan lines, and wherein the data driver divides the plurality of grayscale data into at least two grayscale ranges including a first grayscale range, outputs a first current of the first grayscale range including at least one of the plurality of grayscale data by using the first data, and outputs a second current that corresponds to the second data in the first grayscale range.