Scan Driver Multi-Frequency Masking for Display Power Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Display devices in portable devices, such as smartphones and tablets, face challenges in reducing power consumption when displaying still images, as low frequency driving techniques are not effectively applied across the entire display panel, leading to increased power usage.
Innovation Solution
A scan driver capable of providing multiple scan signals at different driving frequencies to various pixel rows, utilizing a masking control unit to selectively output scan signals based on the driving frequency of each panel region, allowing for multi-frequency driving (MFD) and reducing power consumption by adjusting the scan signal levels according to the image type (still or moving) in different active periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If low frequency driving technique is applied to the entire display panel, then power consumption is reduced, but display quality deteriorates when moving images are displayed
Solution Approach 1:
The display panel is divided into multiple regions (first region and second region) that can be driven at different frequencies independently. The scan driver is segmented into multiple stages, each capable of operating at different frequencies, allowing region-specific frequency control to maintain display quality in moving image areas while reducing power consumption in still image areas.
Solution Approach 2:
Different driving frequencies are applied to different regions based on their content requirements. The first region displays moving images at normal driving frequency while the second region displays still images at low driving frequency, optimizing both display quality and power consumption locally for each region.
2Reliability
If normal driving frequency is applied to the entire display panel, then display quality is maintained, but power consumption increases
Solution Approach 1:
The display panel is divided into multiple regions that can be driven at different frequencies independently. The scan driver is segmented into multiple stages, each capable of operating at different frequencies, allowing region-specific frequency control to maintain display quality in moving image areas while reducing power consumption in still image areas.
Solution Approach 2:
The driving frequency parameter is dynamically changed based on the content type (still image or moving image) in each region. The scan driver receives control signals that adjust the operating frequency of each stage, enabling the system to switch between normal and low driving frequencies to optimize power consumption while maintaining display quality.
3Use of energy by moving object
If multi-frequency driving is implemented, then power consumption is optimized, but device complexity increases
Solution Approach 1:
The scan driver is divided into multiple stages, with each stage corresponding to a specific region of the display panel. Each stage includes frequency control circuitry that can independently adjust its operating frequency based on content type, enabling distributed frequency management that optimizes power consumption without requiring a completely complex centralized control system.
Solution Approach 2:
The driving frequency parameter is dynamically changed based on the content type (still image or moving image) in each region. The scan driver receives control signals that adjust the operating frequency of each stage, enabling the system to switch between normal and low driving frequencies to optimize power consumption while maintaining display quality.
Data Source
AI summary
A scan driver includes: a plurality of stages, each stage including: a logic circuit configured to transfer an input signal to a first node in response to a first clock signal, and to bootstrap the first node in response to a second clock signal; a carry output circuit configured to output the second clock signal as a carry signal that is provided as the input signal for a next stage in response to a voltage of the bootstrapped first node; and a masking controller configured to receive a masking signal and the carry signal, and to output the masking signal as a scan signal provided to a pixel row corresponding to the each stage in response to the carry signal.