Segmented Display Driving for Power Reduction
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Solution Overview
Problem
High-resolution liquid crystal displays with high refresh rates suffer from substantial power losses due to switching inefficiencies, leading to reduced battery life and increased battery size in handheld devices, and lack versatility in providing different viewing modes simultaneously.
Innovation Solution
The active area of the display is categorized into regions, allowing for differential electrical driving to minimize power consumption, with dynamic high-refresh rates applied to color or video regions and reduced rates to monochrome or static regions, optimizing power usage based on content displayed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high refresh rates are applied to the entire display to provide dynamic video content, then visual quality for video regions is improved, but power consumption increases substantially due to switching losses
Solution Approach 1:
The display screen is divided into multiple regions with different refresh rates. The controller identifies video regions requiring high refresh rates (e.g., 2500 Hz) and monochrome regions that can use lower refresh rates (e.g., 250 Hz or 55 Hz). This segmentation allows each region to operate at the minimum necessary refresh rate, reducing overall switching losses while maintaining visual quality in video regions.
Solution Approach 2:
Different portions of the display are assigned different operational characteristics. Video regions receive high-refresh-rate driving waveforms optimized for dynamic content, while monochrome regions receive low-refresh-rate waveforms optimized for static text. This local differentiation ensures that power consumption is minimized in regions where high refresh rates are not necessary, while maintaining visual quality where required.
2Illumination intensity
If the display operates in full colour mode at high refresh rates, then colour video quality is improved, but switching power losses increase by a factor of 5 to 10 times compared to conventional displays
Solution Approach 1:
The display operates in multiple dynamic modes rather than a single static mode. The controller can dynamically switch between full colour mode, partial colour mode, and monochrome mode depending on the content being displayed. This dynamic adaptation allows the system to use full colour high-refresh operation only when necessary, while defaulting to lower-power modes for static or monochrome content, reducing switching power losses by up to 90% in monochrome regions.
Solution Approach 2:
The system changes operational parameters (refresh rate, colour depth, driving waveform) based on content requirements. For video regions, parameters are set to provide full colour at high refresh rates. For monochrome regions, parameters are adjusted to use lower refresh rates and simplified waveforms. This parameter optimization reduces switching losses while maintaining appropriate visual quality for each region's content type.
3Use of energy by moving object
If the refresh rate is reduced in monochrome regions to save power, then power consumption decreases, but visual quality may be compromised
Solution Approach 1:
The system uses feedback from content analysis to determine appropriate refresh rates for different regions. The controller analyzes the displayed content to identify monochrome versus video regions and adjusts refresh rates accordingly. For monochrome regions displaying static text, the system reduces refresh rates to 250 Hz or 55 Hz with optimized waveforms that maintain visual quality. This feedback-driven approach ensures power savings are achieved without compromising visual quality in regions where low refresh rates are sufficient.
Data Source
AI summary
A display screen is capable of having regions having different switching speeds as well as regions that are not switched. One region having a first switching speed may be for colour mode display and the other region having a second switching speed different from the first may be for monochrome mode display. Other regions may be off and not switched. In alternative versions, three or more switched regions may be established on a display screen. For example, a monochrome region may be nested inside a colour region, in which the colour region may be nested between off regions.