Display Touch Sensor Noise Mitigation via Blanking Period Timing
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Solution Overview
Problem
Audible noise is generated in display devices with integrated touch sensors due to the alternating sequence of blanking and display periods, which affects the user experience and system efficiency.
Innovation Solution
Implementing a method where display frames have alternating sequences of display and blanking periods, with varying numbers and durations of blanking periods across different frame types, and adjusting the phase of these periods to spread the noise spectrum, thereby reducing audible noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If blanking periods are used for touch sensing in display frames, then touch sensing capability is improved, but audible noise is generated due to the alternating sequence of blanking and display periods
Solution Approach 1:
The patent applies periodic action by using alternating sequences of blanking and display periods within display frames. The blanking periods are timed to occur at specific intervals to enable touch sensing operations while maintaining display functionality. This periodic structure allows the system to alternate between displaying content and performing touch sensing, resolving the contradiction between maintaining display output and enabling touch input capability.
Solution Approach 2:
The patent employs dynamics by varying the timing and number of blanking periods across different types of display frames. Instead of using a fixed, uniform blanking period structure, the system dynamically adjusts the blanking period configuration to optimize both display performance and touch sensing accuracy while minimizing audible noise generation.
2Measurement precision
If the number of blanking periods is increased for better touch sensing, then touch sensing accuracy is improved, but the complexity of timing and controlling display frames increases
Solution Approach 1:
The patent applies segmentation by dividing display frames into multiple types with different configurations of blanking periods. Instead of using a single uniform blanking structure, the system segments the frame timing into various patterns, allowing touch sensing operations to be distributed across different time intervals. This segmentation enables accurate touch sensing while simplifying the overall timing control by breaking it into manageable segments.
3Object-affected harmful factors
If blanking periods are timed to reduce audible noise, then user experience is improved, but the flexibility in adjusting display and sensing parameters is reduced
Solution Approach 1:
The patent applies parameter changes by adjusting the timing parameters of blanking periods within display frames to optimize the balance between noise reduction and operational flexibility. The system modifies parameters such as the duration, frequency, and positioning of blanking periods to minimize audible noise while preserving sufficient flexibility for display and sensing operations.
Data Source
AI summary
An example method of driving a display having a touch sensor includes: generating a plurality of display frames having an alternating sequence of display and blanking periods; supplying pixel line data to the display during the display periods and sensing signals to the touch sensor during the blanking periods; and timing the blanking periods so that display frames of a first type each have a first number of the blanking periods and that display frames of a second type each have a second number of the blanking periods, the second number less than the first number.