Display Panel Scanning and Driving Circuit Power Reduction
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Solution Overview
Problem
Existing display devices, such as those used in cellular phones, face challenges in reducing power consumption while maintaining picture quality during partial and small gradation displays, as current technologies fail to effectively minimize power usage without compromising image quality.
Innovation Solution
The solution involves a display device and driving method where the display panel is scanned every n lines during a full frame period in multiple gradation mode and every m lines in partial gradation mode, with a shift register and AND circuits time-dividing output data to reduce current flow through the driving circuit, and frame or line reversal is used to reduce charge and discharge power based on display patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the display panel is scanned every line during the whole frame period in non-partial display mode, then the picture quality is maintained, but the power consumption of the driving circuit is high
Solution Approach 1:
The frame period is segmented into multiple scanning periods, where scanning is performed only for the necessary number of lines (m lines) instead of all lines (n lines). This segmentation allows the driving circuit to operate at reduced current during periods when certain lines do not require updating, thereby reducing overall power consumption while maintaining picture quality for the displayed portion.
Solution Approach 2:
The patent implements periodic scanning where the display panel is scanned at full resolution during initial periods and then at reduced resolution during subsequent periods within the same frame period. This periodic variation in scanning intensity allows the system to maintain picture quality when needed while reducing power consumption during stable display states.
2Use of energy by moving object
If the scanning period is reduced in partial display mode, then the power consumption is reduced, but the picture quality may deteriorate
Solution Approach 1:
The patent applies different scanning strategies to different portions of the display. In partial display mode, only the necessary m lines are scanned with full quality parameters, while other lines are either not scanned or scanned with reduced parameters. This local differentiation ensures that picture quality is maintained in the active display region while power consumption is reduced in inactive regions.
3Productivity
If multiple lines are selected simultaneously for writing in partial display, then the writing speed is improved, but the power consumption in the shift register part cannot be reduced
Solution Approach 1:
The patent dynamically adjusts the operation of the shift register based on the display mode. In partial display mode, the shift register operates at reduced speed or is stopped during periods when line selection is not changing, while still maintaining the capability to select multiple lines simultaneously when needed. This dynamic operation allows writing speed to be maintained when necessary while reducing power consumption during stable states.
Data Source
AI summary
A display panel is scanned every two lines during a period of binary writing area in the first half of one frame period in partial display (or in small gradation display) and a steady-state current of an output amplifier for buffering gradation signals supplied to the display panel in a non-scanning period in the second half of one frame period is reduced.