Display Device Scan-Synchronized Sensor Drive for Flicker Control
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Solution Overview
Problem
Display devices experience flickering due to irregular polarity changes in the driving signal of the sensor unit, which can be visually distracting for users.
Innovation Solution
The display device controls the duty cycle of the driving signal by alternating its polarity during each data writing period based on the scan signal, using a time point calculator and signal generator to adjust the final edge of the driving signal to prevent prolonged periods of a single polarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the driving signal maintains a fixed polarity during the data writing period, then the sensor operation is simple and stable, but flickering occurs due to prolonged single polarity
Solution Approach 1:
The patent applies periodic action by alternating the polarity of the driving signal during each data writing period. The signal generator switches between first and second polarities in a periodic manner, ensuring that the polarity alternates with each scan signal cycle. This periodic polarity switching prevents prolonged exposure to a single polarity, thereby eliminating flickering while maintaining stable sensor operation.
Solution Approach 2:
The patent changes the polarity parameter of the driving signal during operation. The signal generator dynamically adjusts the polarity parameter between first and second polarities based on the scan signal timing. This parameter change transforms the signal from a static polarity state to a dynamic alternating state, resolving the flickering issue without compromising operational stability.
2Object-affected harmful factors
If the polarity of the driving signal alternates during each data writing period, then flickering is prevented, but the control complexity increases
Solution Approach 1:
The patent implements feedback by using the scan signal as a timing reference to control the polarity alternation of the driving signal. The signal generator receives the scan signal and generates appropriate driving signals with alternating polarities based on the scan signal's timing information. This feedback mechanism ensures precise polarity switching without requiring complex independent control circuits.
Solution Approach 2:
The signal generator serves multiple functions: it generates the driving signal, controls its polarity alternation, and synchronizes with the scan signal timing. By integrating these functions into a single component, the patent reduces overall system complexity while achieving the polarity switching effect that prevents flickering.
3Object-affected harmful factors
If the final edge of the driving signal is positioned earlier in the data writing period, then polarity alternation is achieved, but the duty cycle decreases
Solution Approach 1:
The patent applies dynamics by making the final edge timing of the driving signal adjustable rather than fixed. The signal generator dynamically positions the final edge at different time points within the data writing period, allowing optimization between duty cycle length and polarity alternation effectiveness. This dynamic adjustment enables the system to achieve flicker prevention while maintaining adequate duty cycle.
Data Source
AI summary
A display device including: a display driver configured to output a scan signal during a frame period, the frame period including at least one data writing period; and a sensor driver configured to control a duty cycle of a driving signal during the data writing period based on the scan signal.62