EEPROM Baseline Storage for Touch Sensor Uniformity
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Solution Overview
Problem
Existing touch and proximity sensor panels face challenges in maintaining a uniform response due to variations in sensor electrical characteristics, leading to false triggering or non-triggering of virtual buttons, especially when fingers or objects are present during boot-up, which corrupts the baseline output values.
Innovation Solution
Pre-stored no-touch or no-hover sensor output values are used to establish an initial baseline, unaffected by fingers or objects, and then normalized, allowing for consistent detection of touch or hover events across the sensor panel. This involves capturing raw baseline values before assembly and storing them in non-volatile memory, and using them during boot-up to compute offsets for subsequent output values, discarding the pre-stored baseline once a new, accurate one is captured.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If baseline values are captured during boot-up, then the baseline can be used for subsequent touch detection, but fingers or objects present during boot-up will corrupt the baseline values
Solution Approach 1:
The patent applies preliminary action by capturing baseline values during manufacturing before the device is assembled and before it can be contaminated by fingers or objects. These pre-captured baseline values are stored in memory and used during initial boot-up, eliminating the risk of contamination that would occur if baselines were captured after assembly.
2Manufacturing precision
If sensor output values vary due to electrical characteristic differences, then manufacturing variations are reflected in sensor response, but this leads to false triggering or non-triggering of virtual buttons
Solution Approach 1:
The patent applies parameter changes by capturing the actual output values of each sensor element during manufacturing and using these captured parameters to adjust and normalize the response of each sensor. This compensates for manufacturing variations in electrical characteristics, ensuring uniform response across all sensors and accurate virtual button triggering.
Data Source
AI summary
Pre-stored no-touch or no-hover (no-event) sensor output values can initially be used when a sensor panel subsystem is first booted up to establish an initial baseline of sensor output values unaffected by fingers or other objects touching or hovering over the sensor panel during boot-up. This initial baseline can then be normalized so that each sensor generates the same output value for a given amount of touch or hover, providing a uniform response across the sensor panel and enabling subsequent touch or hover events to be more easily detected. After the initial normalization process is complete, the pre-stored baseline can be discarded in favor of a newly captured no-event baseline that may be more accurate than the pre-stored baseline due to temperature or other variations.