Alternating Column Refresh for Display Power Reduction
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Solution Overview
Problem
Display panels consume significant power, especially during idle periods, and reducing refresh rates to conserve power results in visual artifacts like flickering due to the sawtooth decay of storage capacitance in LCDs, which is undesirable.
Innovation Solution
The solution involves alternating the refresh of even and odd columns of a display panel at different frame rates during idle periods, with only half the columns being refreshed at a slower rate, reducing power consumption without causing visual artifacts by leveraging the storage capacitors to maintain pixel values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the refresh rate is reduced to conserve power during idle periods, then power consumption decreases, but visual artifacts like flickering occur due to storage capacitance decay
Solution Approach 1:
The patent divides the display panel into two separate column groups (even columns and odd columns) that are refreshed alternately at different times. This segmentation allows the system to refresh only half the columns at a given refresh cycle, effectively reducing the power consumption while maintaining acceptable visual quality through the alternating refresh pattern.
Solution Approach 2:
The patent implements a periodic alternating refresh scheme where even columns are refreshed during even frames and odd columns are refreshed during odd frames. This periodic action creates a lower effective refresh rate for each column group, reducing power consumption while the alternating pattern prevents visible flicker by ensuring continuous updates across the entire display.
2Reliability
If larger storage capacitance is used to reduce decay effects, then visual artifacts are reduced, but latency increases and source driver power consumption increases
Solution Approach 1:
By segmenting the column refresh operations into alternating even and odd column groups, the patent reduces the power consumption of source drivers since they only need to drive half the columns at any given time. This segmentation approach maintains visual quality through the alternating refresh pattern without requiring larger storage capacitance or increasing overall power consumption.
Solution Approach 2:
The patent applies partial action by refreshing only a subset of columns (either even or odd) during each refresh cycle rather than refreshing all columns simultaneously. This partial refresh approach reduces the instantaneous power demand on source drivers while the alternating pattern ensures complete coverage over time, avoiding the need for excessive capacitance.
Data Source
AI summary
A method for refreshing a display. The method includes refreshing even and odd columns of a display panel at a first frame refresh rate where for each frame, even and odd columns are refreshed. Upon entering a display idle period, a low power display refresh is performed. The low power display refresh includes: refreshing the even columns of the display during even frames while circuitry driving odd columns are not used, and refreshing the odd columns of the display during odd frames while circuitry driving the even columns are not used. Refreshing the even columns and refreshing the odd columns are performed at a second frame refresh rate that is slower than the first frame refresh rate.